bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular Screening for Urothelial Cancer: How Close We Are?
Authors: Michas Athanasios , Michas Basileios , Tsitsibis Anastasios , Tsoukalas Nikolaos
Published: May 2023

Early detection of urothelial cancer offers the potential for effective and successful treatment. Despite previous efforts, currently, there is not a well-validated, recommended screening program in any country. This integrative, literature-based review provides details on how recent molecular advances may further advance early tumor detection. The minimally invasive liquid biopsy is capable of identifying tumor material in human fluid samples from asymptomatic individuals. Circulating tumor biomarkers (cfDNA, exosomes, etc.) are very promising and are attracting the interest of numerous studies for the diagnosis of early-stage cancer. However, this approach definitely needs to be refined before clinical implementation. Nevertheless, despite the variety of current obstacles that require further research, the prospect of identifying urothelial carcinoma by a single urine or blood test seems truly intriguing.
Improving cathode designs for solid-state lithium batteries with high energy density
Authors: Thompson Avery
Published: May 2023

3D current collectors and in situ solidification of polymer electrolytes enable high cathode mass loading without sacrificing charge transfer kinetics.
Quantum diamond magnetometer approach paves way for imaging neurons with microscopic precision
Authors: Liebendorfer Adam
Published: May 2023

Combining double resonance with hyperfine driving yields the ability to detect nanotesla-scale magnetic fields on the micron level in less than a millisecond.
Understanding model uncertainty key to fabricating future materials
Authors: Shapiro Maura
Published: May 2023

For machine learning models predicting new material properties, reducing uncertainty minimizes cost.
The effect of chronic kidney disease on tissue formation of in situ tissue-engineered vascular grafts
Authors: Besseling Paul J. , Krebber Merle M. , Fledderus Joost O. , Teraa Martin , den Ouden Krista , van de Kaa Melanie , de Bree Petra M. , Serrero Aurelie , Bouten Carlijn V. C. , Dankers Patricia Y. W. , Cox Martijn A. J. , Verhaar Marianne C.
Published: May 2023

Vascular in situ tissue engineering encompasses a single-step approach with a wide adaptive potential and true off-the-shelf availability for vascular grafts. However, a synchronized balance between breakdown of the scaffold material and neo-tissue formation is essential. Chronic kidney disease (CKD) may influence this balance, lowering the usability of these grafts for vascular access in end-stage CKD patients on dialysis. We aimed to investigate the effects of CKD on in vivo scaffold breakdown and tissue formation in grafts made of electrospun, modular, supramolecular polycarbonate with ureido-pyrimidinone moieties (PC-UPy). We implanted PC-UPy aortic interposition grafts (n = 40) in a rat 5/6th nephrectomy model that mimics systemic conditions in human CKD patients. We studied patency, mechanical stability, extracellular matrix (ECM) components, total cellularity, vascular tissue formation, and vascular calcification in CKD and healthy rats at 2, 4, 8, and 12 weeks post-implantation. Our study shows successful in vivo application of a slow-degrading small-diameter vascular graft that supports adequate in situ vascular tissue formation. Despite systemic inflammation associated with CKD, no influence of CKD on patency (Sham: 95% vs CKD: 100%), mechanical stability, ECM formation (Sirius red+, Sham 16.5% vs CKD 25.0%–p:0.83), tissue composition, and immune cell infiltration was found. We did find a limited increase in vascular calcification at 12 weeks (Sham 0.08% vs CKD 0.80%—p:0.02) in grafts implanted in CKD animals. However, this was not associated with increased stiffness in the explants. Our findings suggest that disease-specific graft design may not be necessary for use in CKD patients on dialysis.
Theoretical investigation of Rayleigh surface acoustic wave propagation characteristics in c-axis-zigzag ScAlN film/silicon substrate structure
Authors: Tominaga Takumi , Takayanagi Shinji , Yanagitani Takahiko
Published: May 2023

Surface acoustic wave (SAW) resonators are key components of mobile communication systems, and the development of wideband SAW resonators is especially required because next-generation mobile communication systems require high-speed data transmission using wide frequency bands. In this study, two layered structures—(i) a c-axis-tilted ScAlN bilayer film/silicon substrate and (ii) a c-axis-zigzag ScAlN film/silicon substrate—are proposed for highly coupled SAW resonators, and the electromechanical coupling coefficient K2 of the non-leaky Rayleigh-mode SAW propagating in these structures is investigated theoretically. With a proper c-axis tilt angle and thickness selection of the ScAlN film, the first-mode Rayleigh SAW in the c-axis-tilted ScAlN bilayer film/silicon substrate and c-axis-zigzag ScAlN film/silicon substrate offers high K2. The maximum K2 was 9.56%, obtained in the c-axis-zigzag ScAlN film/silicon substrate structure, which was 2.5 times the maximum K2 in the c-axis-tilted ScAlN monolayer film/silicon substrate structure; this is because the c-axis-zigzag ScAlN films increase the shear vertical component of the SAW particle displacement, most of which is concentrated in the c-axis-zigzag ScAlN film on the silicon substrate. It is also important that the second-mode SAW (Sezawa wave) in the c-axis-zigzag ScAlN film/silicon substrate structure is not excited when the K2 value of the first-mode SAW is maximized. The techniques for fabricating a c-axis-tilted ScAlN film and a c-axis-zigzag ScAlN film have been reported, and well-established micromachining technology related to silicon semiconductors offers significant advantages in the manufacturing and processing of SAW resonators. Therefore, the c-axis-zigzag ScAlN film/silicon substrate structure has significant potential for SAW device applications.
Phase-space tomography in magnetically confined plasmas
Authors: Kobayashi T. , Yoshinuma M. , Hu W. , Ida K.
Published: May 2023

In this paper, a tomography approach aiming at reconstructing a phase-space structure is proposed. For the phase-space resolved diagnostic system, a signal must be decomposed in real-space, velocity-space, and time; therefore, it is challenging to obtain a sufficiently high signal intensity in a single detector bin. To overcome this difficulty, three different sets of data having different integration directions in real-space, velocity-space, and time are simultaneously used, and a reconstruction of the original structure in the phase-space is attempted by a tomographic manner. The proposed method is demonstrated using a synthetic dataset in the actual diagnostic setup in the Large Helical Device. Time evolution of a phase-space perturbation induced by the Landau damping, which is caused by energetic particle-driven magnetohydrodynamic bursts, is successfully reconstructed by this method. Robustness against realistic diagnostic noise is also presented.
Regulatory elements coordinating initiation of chromosome replication to the
Escherichia coli
cell cycle
Authors: Knöppel Anna , Broström Oscar , Gras Konrad , Elf Johan , Fange David
Published: May 2023

Escherichia coli
coordinates replication and division cycles by initiating replication at a narrow range of cell sizes. By tracking replisomes in individual cells through thousands of division cycles in wild-type and mutant strains, we were able to compare the relative importance of previously described control systems. We found that accurate triggering of initiation does not require synthesis of new DnaA. The initiation size increased only marginally as DnaA was diluted by growth after
dnaA
expression had been turned off. This suggests that the conversion of DnaA between its active ATP- and inactive ADP-bound states is more important for initiation size control than the total free concentration of DnaA. In addition, we found that the known ATP/ADP converters
DARS
and
datA
compensate for each other, although the removal of them makes the initiation size more sensitive to the concentration of DnaA. Only disruption of the regulatory inactivation of DnaA mechanism had a radical impact on replication initiation. This result was corroborated by the finding that termination of one round of replication correlates with the next initiation at intermediate growth rates, as would be the case if RIDA-mediated conversion from DnaA-ATP to DnaA-ADP abruptly stops at termination and DnaA-ATP starts accumulating.
Manipulating plasma turbulence in cross-field plasma sources using unsteady electrostatic forcing
Authors: Rose Benedict I , Knoll Aaron
Published: May 2023

Unsteady electrostatic forcing is investigated as a method for manipulating turbulent plasma behaviour within Hall-effect thrusters and similar cross-field plasma devices using a simplified one-dimensional three-velocity azimuthal electrostatic particle-in-cell simulation. A wide range of axial electric field forcing frequencies from 1 MHz up to 10 GHz at amplitudes of 10 V cm−1, 50 V cm−1 and 100 V cm−1 are applied to the plasma and the response is evaluated against a baseline case defined by the community benchmark LANDMARK Test Case 1. ‘Tailoring’ of plasma parameters, such as the electron cross-field mobility, is demonstrated via manipulation of the electron drift instability using unsteady forcing. Excitation of the unstable electron cyclotron modes by the electron drift instability is shown to be able to produce a reduction of the resultant electron cross-field mobility of the plasma by up to 50% compared to the baseline value. Additionally, forcing at the electron cyclotron frequency appears to be capable of increasing cross-field mobility by up to 2000%. Implications of the results for direct drive electric propulsion systems and improved current utilization efficiencies for Hall-effect thrusters are discussed.
Electrokinetic ion enrichment in asymmetric charged nanochannels
Authors: Gao Chunfang , Zhong Shile , Liu Zheng , Li Changzheng
Published: May 2023

Artificial bionic nanochannels have attracted wide attention and successfully used in various fields. In this work, a novel nanochannel with asymmetric surface charge is proposed to investigate the ion enrichment effect. The results show that the proposed nanochannel has excellent ion enrichment performance and the obtained ion enrichment ratio is up to 1500 when the ion concentration is 0.01 mM, which is much higher than precedent researches typically ranging from tens to hundreds. Besides, we found that the forward voltage bias will produce ions enrichment and the reverse voltage bias will produce ions depletion. The ion enrichment ratio is higher at the larger voltage bias, absolute surface charge density and smaller nanochannel height. In addition, the ion enrichment performance is more sensitive to the change of charged wall length and not sensitive to the change of uncharged wall length. The research report offers important information and instructions for the design and optimum on ion enrichment performance.
Determining the centres of mass of a circular arc and a circular sector using the principle of virtual work
Authors: Manukyan Vardan , Nikoghosyan Gagik
Published: May 2023

In studying physics, it is important to solve problems with different methods and compare current and final results, which allows more comprehensive and deep analysis of the observed processes. In this paper, at a level of school physics course, the application of the principle of virtual work is presented as an alternative to the standard method for solving problems of statics. Two approaches are used to analyse two problems, as a result of which, without the use of integral calculus, formulas for the centres of mass of a circular arc and a circular sector are obtained.
Investigation of multi-fingers drain field plate in dual-threshold coupling AlGaN/GaN high electron mobility transistors for optimizing linearity at high electrical fields in the Ka band
Authors: Wang Pengfei , Mi Minhan , Chen Yilin , an Sirui , Zhou Yuwei , Zhou Jiuding , Zhao Ziyue , Zhu Qing , Du Xiang , Gong Can , Li Ming , Ma Xiaohua , Hao Yue
Published: May 2023

GaN high electron mobility transistors were fabricated and investigated in detail to improve their linearity at high operating voltage. The scheme of dual-threshold (DT) coupling was adopted to mitigate the transconductance (G
m) nonlinearity and a multi-fingers drain field plate (MF-DFP) was employed to alleviate the high electric field. The proposed GaN HEMT, integrating the DT technique (DT HEMT) and MF-DFP structure (DT HEMT W/ MF-DFP), yielded a G
m plateau of ∼5.5 V and a ∼8 dB improvement in the calculated output third-order intercept point(OIP3) than that of DT HEMT. The load-pull measurements at 30 GHz delivered a peak power-added efficiency (PAE) of 52.5 % at V
ds = 10 V, and saturation output power density (P
out) of 5.5 W mm−1 at V
ds = 20 V. In comparison with the DT HEMT, the DT HEMT W/ MF-DFP obtained a flatter gain profile, with ∼1.5 dB improvement in gain compression at V
ds = 20 V.
Improved characteristics of MoS2 transistors with selective doping using 1,2-dichloroethane
Authors: Jeong Wonchae , Kim Taeyoung , Kim Yoonsok , Jeong Mun Seok , Kim Eun Kyu
Published: May 2023

We demonstrate area-selective doping of MoS2 field-effect transistors using 1,2-dichloroethane (DCE) solution. In the device manufacturing process, area-selective chemical doping was used to implement contact engineering in the source/drain region. X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy measurements were performed to confirm the blocked layer (BL) using a photoresist, which suppressed the doping effect of the DCE treatment. In the XPS results, the main core level of the MoS2 flake with BL did not shift, whereas that of the MoS2 flake without BL changed by approximately 0.24 eV. In the case of the MoS2 flakes with a BL, the vibrational modes of the Raman scattering did not shift. Conversely, the two Raman peaks of the MoS2 flake without BL red-shifted because of increasing electron–phonon scattering. The effect of area-selective doping was confirmed by electrical measurements. The field-effect mobility and the subthreshold swing were enhanced from 4.07 to 31.5 cm2 (V s)−1 and from 1.26 to 0.401 V/decade, respectively.
Exploring the suitability of narrow-bandgap compounds for thermoelectric application
Authors: Popoola A I , Odusote Y A , Ogunjo S T , Distasio R A
Published: May 2023

Different opinion exists regarding the role of bandgap size on thermoelectric variables. Motivated by the observation that the band shape can in a definite way affect thermoelectric properties, two compounds (BaSiSr and IrBiZr) have been evaluated for optimum thermoelectric application. The phonon spectrum, band structure, mechanical and thermoelectric properties of the two compounds were investigated using the density functional theory. The calculated bandgap size of the compounds are comparable (IrBiZr = 0.223 eV; BaSiSr = 0.220 eV). The valence energy edge peaked at the Fermi level for both compounds. The highest valence energy edge occurred at a single high symmetry point (Γ for IrBiZr) but at two symmetry points (X and W for BaSiSr). IrBiZr gave an overall superior performance over BaSiSr in the calculated elastic, thermodynamic and thermoelectric parameters. A lesser role for bandgap size can therefore be indicated in the design and optimization of novel thermoelectric materials in view of better results in favor of IrBiZr than BaSiSr.
Tunability of bandgap from UV to visible region by transition metal ion implantation in CeO2 and their electronic structures
Authors: Singh Anshu , Saini Richa , Kumar Pawan , Gupta Mukul , Kandasami Asokan
Published: May 2023

The present report examines the tunability of optical band gap by 150 keV Fe ion implantation in cerium oxide (CeO2) thin films and their electronic structures. X-ray diffraction (XRD) confirms the stable FCC structure and these films lose their crystalline nature with increasing ion fluences. Atomic force microscopy (AFM) shows the morphology changes. Raman measurement exhibits the presence of defect states. UV–vis spectroscopy reveals that the optical band gap reduces from 3.14 eV to 2.70 eV. These results are well correlated with the electronic structure studies from the x-ray photoelectron spectroscopy (XPS) and x-ray absorption spectroscopy (XAS). The XPS indicates the existence of Ce3+ due to the replacement of Fe3+ which reduces the Ce4+ to Ce3+ ions. XAS at the Ce-M4,5 edge reveals the change in Ce4+→Ce3+ with Fe ion fluence and the O-K edge spectra show that the vacancies are introduced after Fe ion implantation. The edge shifting of the O-K edge confirmed the presence of Ce4+-VO-Ce3+ and Ce3+-VO-Fe3+ networks in Fe-implanted thin films. This reversible ability enables the CeO2-based nanomaterial for energy and environmental-related applications.
Simulation of cathode spots crater formation on electrodes with micro-scale and nano-scale alloy materials in a vacuum arc
Authors: Wang Lijun , Zhang Runming , Gao Hexiao , Li Jiagang , Wang Cong
Published: May 2023

In the field of vacuum interrupting, an important research is to improve the erosion resistance properties of contacts. In this paper, a two-dimensional axisymmetric swirl model based on basic parameters has been proposed to describe the formation and development of cathode spots of micro-scale alloy and nano-scale alloy electrode in a vacuum arc. In this model, the peak ion density of the plasma cloud, the mean charge state in near-cathode region, the electron temperature, and the near-cathode voltage drop are adopted as external parameters. Ions and electrons originating from the plasma cloud, thermo-field (T-F) emission, vaporization of metal atoms, backing ions and back-diffused electrons are all taken into consideration. The morphology and temperature of cathode spots crater and the liquid metal velocity of pure copper electrode (Cu), copper-chromium (Cu-Cr) electrode and tungsten-copper (W-Cu) electrode under the conditions of micro-scale grains and nano-scale grains are compared, respectively. Simulation results show that the cathode spot crater of the Cu-Cr electrode is smaller than that of the pure copper electrode. Moreover, it can hold more current and inhibit the formation of new cathode spots nearby. Cathode spots appearing on tungsten grains are smaller in size and have a lower probability of forming liquid metal droplets than Cu-Cr electrodes. Contacts made of nano-scale grain alloys have stronger erosion resistance properties than that of micro-scale alloy contacts and can reduce the maximum temperature of the cathode. The simulation results are in good agreement with other researchers’ results.
Lyman-α polarization from cosmological ionization fronts. Part I. Radiative transfer simulations
Authors: Yang Yuanyuan , Koivu Emily , Zeng Chenxiao , Long Heyang , Hirata Christopher M.
Published: May 2023

In this paper, we present the formalism of simulating Lyman-α emission and polarization around reionization (z = 8) from a plane-parallel ionization front. We accomplish this by using a Monte Carlo method to simulate the production of a Lyman-α photon, its propagation through an ionization front, and the eventual escape of this photon. This paper focuses on the relation of the input parameters of ionization front speed U, blackbody temperature T
bb, and neutral hydrogen density n
HI, on intensity I and polarized intensity P as seen by a distant observer. The resulting values of intensity range from 3.18 × 10-14 erg/cm2/s/sr to 1.96 × 10-9 erg/cm2/s/sr , and the polarized intensity ranges from 5.73 × 10-17 erg/cm2/s/sr to 5.31 × 10-12 erg/cm2/s/sr. We found that higher T
bb, higher U, and higher n
HI contribute to higher intensity, as well as polarized intensity, though the strongest dependence was on the hydrogen density. The dependence of viewing angle of the front is also explored. We present tests to support the validity model, which makes the model suitable for further use in a following paper where we will calculate the intensity and polarized intensity power spectrum on a full reionization simulation.
Thermal buckling behavior of metal/composite wall panels
Authors: Deng Wen-liang , Wang Bin-Wen , Lei Kai , Wu Jing-Tao
Published: May 2023

This paper has carried out the research on the thermal buckling behavior of the metal/composite composite structure wall panel. The thermal buckling behavior of the hybrid structure has been studied from analytical methods, finite element methods and experimental tests. Aiming at the thermal buckling behavior of the hybrid structure from room temperature 20°C to -55°C, non-contact optical testing technology is used to obtain the thermal buckling deformation parameters of the entire temperature history, and the critical heat of the hybrid structure is obtained through theoretical solution, simulation and data judgment methods. The buckling temperature reveals the thermal buckling deformation law of the mixed structure wall panel under the aircraft temperature envelope. Conclusion: The change of structural off-plane displacement is the manifestation of structural buckling instability.Although buckling instability occurs in the wall structure during the cooling process, the structure can still be restored to a normal state without post-buckling. The slope of structural deformation changes dramatically after -15°C, basically showing a linear relationship; the theoretical solution, simulation method and data judgment method determine the critical temperature of structural thermal buckling with a maximum difference of 4.8°C. The test data judgment method can be used for thermal buckling Determination of critical load.
Three-dimensional numerical study on the interaction between RDC and NGV
Authors: Xue Sainan , Yang Bo , Liu Denghang , Xia Zhenjuan , Ma Hu
Published: May 2023

In this paper, the three-dimensional numerical method is used to study the change of the internal flow field distribution characteristics of a RDC with a deflector installed at the outlet, using the premixed gas of kerosene and air as reactants. It is found that the total pressure in the front section of the combustor has been improved. Different configurations of deflectors were designed. It was found that the flow field in the combustion chamber could not be significantly changed by changing the number of blades, but the maximum average total pressure and the total pressure loss in the mixing section could be effectively improved by adjusting the angle of incidence. Because the propagation direction of rotating detonation wave and the deflector blade have directionality, the study found that when the two directions are opposite, the reflected shock wave formed at the inlet of the deflector changes greatly, the working environment of the fixed blade is worse, the uniformity of gas after passing the deflector decreases, the flow field along the axial average total pressure loss increases significantly, and the peak value of the total pressure shifts significantly downstream. The study of the interaction between NGV and RDC provides a basis for the design of the rotaing detonation turbine engine.
Parameter modelling of fleet gas turbine engines using gated recurrent neural networks
Authors: Shuai M , Yafeng W , Hua Z , Linfeng G
Published: May 2023

Oriented by the gas-path fault diagnosis of aircraft engines, this work presents a novel parameter modelling scheme for fleet gas turbine engines based on gated recurrent neural networks. Four dynamic models are constructed based on the long short-term memory (LSTM) network and gated recurrent unit (GRU) network to predict the total temperature at the high-pressure turbine outlet of gas turbine engines. We apply the dynamic networks to model the engine parameters by solving a sequence-to-feature regression problem. The proposed scheme is assessed through a comprehensive comparison study on training performance, validation performance, generalization, robustness against noise, and extrapolation performance. The results showed that the proposed network models performed a promising performance on parameter modelling. For the proposed four network models, the NARX-based models have better one-step-ahead prediction performance, while the state-space-based models have better long-term prediction performance. The discussion of the results also showed that the GRU network was an effective data-driven model for parameter modelling of gas turbine engines.
Numerical study of nozzle erosion in a hybrid rocket motor with wagon wheel fuel grain
Authors: Jiang Xianzhu , Tian Hui , Diao Chengyong , Yu Ruipeng , Zhao Sheng , Zhu Hao
Published: May 2023

Nozzle erosion directly affects the design quality of hybrid rocket motors, and it is a critical issue that restricts the practical application of hybrid rocket motors. In this paper, coupled numerical simulations of combustion flow field and thermochemical erosion of a graphite nozzle in a hybrid rocket motor with multi-port wagon wheel fuel grain are carried out. The results indicate that distributions of temperature, species and erosion rate in the flow field of hybrid rocket motor with wagon wheel grain show symmetrical characteristics related to the grain shape. The erosion rate decreases at first and then increases at the convergent section of throat insert, and it reaches the maximum value at the transition arc between convergent section and straight section of the throat. The maximum erosion rates at the central hole (position A) and outer edge of wheel holes (position B) are 0.0625 mm/s and 0.0902 mm/s, respectively. The erosion rate increases slowly in the straight section of the throat and it decreases gradually in the divergent section. Circumferentially inhomogeneous ablation occurs in the throat, and the erosion rate at the front end of throat straight section varies from 0.0484 mm/s to 0.0809 mm/s. The main oxidizing species causing thermochemical erosion are H2O and OH. At position A in the front end of throat straight section, erosion rates caused by H2O and OH are 66.50% and 30.48%, respectively. With the increase of oxidizer mass flow rate, the combustion chamber pressure increases linearly, and the erosion rate at position A in the front end of throat straight section gradually increases, but the growth rate decreases.
An advanced warning model of airplane hard landing based on Adaboost
Authors: Zhang R , Cai L Y T , Huang D J , Gao C Y
Published: May 2023

This paper breaks through the limitation of establishing early warning logic in the time dimension of the previous hard landing early warning model. In this research, flight altitude has been set as the scale of the corresponding early warning logic. According to the specific characteristics of the original flight parameter data set, the data preprocessing methods have been studied. The application of oversampling and frequency compression methods effectively solved the problems of different sample size and multi-frequency flight parameters in the original data set. On this basis, the method of ensemble learning is used to establish the early warning model of aircraft hard landing based on Adaboost. Further, the model is optimized to ensure the accuracy and generalization ability of the early warning model. Verified by the case study of the actual flight parameter data of Airbus A320 aircraft, the early warning model can realize high-precision prediction of hard landing events, which is of great significance for the improvement of the landing safety level of the aircraft in constructing both.
Double three-phase permanent magnetic motor based on the smallest copper consumption and maximum torque single phase lack of phase compromise and tolerance error control
Authors: Song Bing , Cui Yebing , Zhang Xinbin , Fang Cheng , Wang Kai
Published: May 2023

In multiphase motors, the consumption of stator copper and the output of torque are a pair of constraints affecting motor control performance. According to the constraint relationship between the them, this paper proposes a method to balance the consumption of copper and the output of torque by using the weight coefficient. Through this method, the efficient control of fault-tolerant motors can be realized, and the balance of output torque and efficiency can be realized. Finally, the accuracy of the control strategy is verified by the motor loading platform.
Influence of cavitation state and launch angle on water-exit process of vehicle based on moving domain method
Authors: Li Jiamin , Zheng Jian , Jing Shibo
Published: May 2023

This paper, aiming at the water-exit process of the vehicle with cavitation, based on the moving domain method coupled with the SDOF (six degrees of freedom) solver, using VOF (volume of fluid) multiphase model and the Schnerr-Sauer cavitation model, carrying out numerical simulation research on multi-conditions. Comparing vertical launch vehicles with different water-exit Ca (cavitation number) cases, the sudden decrease in cavitation number is closely related to the cavitation state, and there is a maximum influent cavitation state of the cavitation collapse on the process of the water-exit. Comparing different initial launch angle cases, it is found that there is a most unstable launch angle, which makes the angular deflection of the vehicle the most severe during the water-exit process.
Research on the association algorithm of space-target track segments
Authors: Jia Senhao , Sun Shaoyong , Qu Weizhi , Jin He , Li Libin
Published: May 2023

In order to improve the tracking continuity and stability of space targets, the track segments association algorithms are studied. The extrapolation prediction based on the C-W motion model in the main spacecraft orbital coordinates is carried out. The model of space target is used to forecast and extrapolate the trajectory of the interrupted target. Based on the extrapolation of the terminated track, the track segments are associated by using the extrapolation results and the state update values at the first few moments of each track segment after the interruption. In this way, the association and fusion of the orbit of the space target interruption is completed. The results can improve the tracking accuracy of space targets and the trajectory association.
The effect of reflux schemes in hydrogen peroxide electric pump on anti-cavitation of inducer
Authors: Gu Xiaoming , Tian Hui , Wang Jiangning , Lu Yudong , Jiang Xianzhu , Zhu Hao
Published: May 2023

Hydrogen peroxide electric pump supply system can provide an improvement to hybrid rocket motor performance. Due to the physical and chemical properties of hydrogen peroxide, a canned pump scheme is more suitable to be used in hybrid rocket motor. The high-temperature liquid between the rotor and stator of the electric pump, returning to the inlet of the inducer, has a considerable influence on the anti-cavitation performance. The numerical simulation results show that the optimal reflux scheme is different when the inlet pressure range of the inducer is different. When the inlet pressure of the inducer is 0.4 MPa, the performance of the inducer is less affected by the reflux schemes, and the optimal scheme is the axial scheme in the simulation. When the inlet pressure is 0.12 MPa and there is a large cavitation area in the inducer, the radial reflux scheme is better than the axial and mixed reflux. When the inlet pressure is 0.1 MPa and the cavitation areas almost extend to the whole blade passage, the radial reflux scheme is much better than the axial and mixed reflux.
Fault detection and isolation of electromechanical actuator based on SAE-BiLSTM
Authors: Tao Xinxin , Guo Yingqing , Zhao Wanli , Zhou Qifan , Xu Kejie
Published: May 2023

The control technology of electromechanical actuator(EMA) and its fault diagnosis is one of the key problems of multi-electric aircraft study. The method based on deep learning is used to diagnose and isolate the classic faults of EMA. The simulation model of EMA is modeling according to the working principle and control law. Four typical faults of EMA are studied,including return channel jam, spall, motor fault, and position sensor fault. Sparse Auto Encoder (SAE) algorithm can perform adaptive extraction of sensor data, which preserves dimensionality reduction and compression while preserving important features. Bidirectional Long Short Term Memory (BiLSTM) neural network is used to effectively process the time series data, which considering both past and future data during the fault diagnosis process. The established EMA model is simulated to obtain normal and faulty data sets, which are used to train the network by SAE-BiLSTM algorithm, and then the trained network is used for online fault diagnosis. After the experiment, SAE-BiLSTM algorithm can well complete the EMA fault detection and isolation.
Numerical analysis of separation dynamics for space debris removal payload based on solid thruster
Authors: Tao Xiaoyu , Yang Haibo , Deng Hanyu , Zhou Hao
Published: May 2023

Aiming at the current mainstream flying anchor payload for space debris removal, a solid thruster was proposed as the separation driving force, and a complete dynamic model of the spacecraft platform and payload were established. The effects of the gap between the directional button and the directional tube, thrust eccentricity and the initial attitude of the platform on the target accuracy under the flying anchor payload were studied. The analysis results showed that the initial attitude of the platform was the main factor affecting the target accuracy of the flying anchor payload. The control gap between 0.1mm ~ 0.25mm can effectively reduce the displacement of payload separation and the influence of disturbance on the platform.
A SysML-centric integration framework for helicopter fuel system development
Authors: Zhao H , Wu W K , Hu X M , Guo Y Q , Zhang C , Hao G X
Published: May 2023

Data and model exchange between SysML (Systems Modeling Language) Modeling tools and other system development tools is a critical aspect of Model-Based Systems Engineering (MBSE). This paper introduces an application of the SysML-centric integration framework, which allows integrating multi-disciplinary engineering models into a SysML Modeling environment. A design practice of helicopter fuel system is then presented to illustrate how to combine the external simulation models within the SysML Models to explore the performance and verify corresponding requirements. In this case, FMI (Functional Mock-up Interface) based co-simulation creates a bridge between SysML Modeling tools and simulation tools in the SysML-centric integration framework. According to the practice, we believe it will significantly improve model consistency and traceability to provide early evaluation of concepts during conceptual design phase.
Research on transition state control strategy of propfan engine based on SAC algorithm
Authors: Zhou Jiang-tao , Wang Ya-fan , Yang Zhao-xing , Zhao Dong-zhu
Published: May 2023

The engine performance search control plays a key role in the engine operation. How to find a suitable algorithm to make the control process fast and stable without exceeding various engine constraints is very important. With the continuous development of deep reinforcement learning in recent years, not only many deep reinforcement learning algorithms have emerged, but also deep reinforcement learning has made rapid development in the field of control. Considering the strong perception and decision-making ability of the deep reinforcement learning algorithm, and in order to adapt to the strong nonlinearity of the engine model and avoid falling into the local optimal value, this paper uses the SAC (Soft Actor Critical, SAC) algorithm to optimize the transition state performance. By introducing the strategy information entropy into the objective function, the search stability of the algorithm and the final optimization effect are significantly improved. Finally, the SAC algorithm is compared with the DDPG algorithm to optimize the transition state performance, and the results show that the SAC algorithm has a better optimization effect on the transition state performance.
Can data sharing really provide added value? Practical data sharing recommendations for the wind energy sector
Authors: Barber S , Hammer F , Henderson C
Published: May 2023

The digital era offers many opportunities to the wind energy industry and research community and digitalisation is one of the key drivers for reducing project costs and risks. The WeDoWind framework has been developed in order to address one of the main challenges to a successful exploitation of digitalisation in wind energy - data sharing and collaboration. The main innovation of this framework is the way it creates tangible incentives to motivate different types of people to actually share data and knowledge in practice. In this work, we carry out a detailed analysis of the strengths and weaknesses of the WeDoWind framework based on a survey filled out by participants of two use case studies and observations from the WeDoWind development team. The results show that the framework successfully enhances collaboration and data sharing in the sector. The results allowed a set of practical data sharing recommendations for the wind energy sector to be developed, which are being continuously improved based on our experience with the WeDoWind framework. They can be applied by anyone wishing to share data effectively and efficiently.
Offshore wind in the race for ocean space: A forecast to 2050
Authors: Pettersen S S , Aarnes Ø , Arnesen B , Pretlove B , Ervik A K , Rusten M
Published: May 2023

This paper reports on recent results on the race for space in our ocean, based on DNVs forecasting efforts into the Blue Economy. We find that the world will see a large increase in the usage of ocean area by offshore installations for energy and food production, with the European area for installations growing close to five-fold to 2050. If not carefully managed, the energy transition in the ocean risks triggering a race for space and conflicts with other stakeholders. By introducing the Spatial Competition Index (SCI), we propose a new indicator to measure the level of competition among ocean industries and nature. SCI forecasts to 2050 reveal that shallow waters close to shore will face significant increases in pressure from ocean industries. This indicates that there is a need for co-existence to be considered in new offshore wind development projects, and for developers to increasingly consider floating structures.
Effect of curtailment scenarios on the loads and lifetime of offshore wind turbine generator support structures
Authors: Robbelein Koen , Daems P.J. , Verstraeten T. , Noppe N. , Weijtjens W. , Helsen J. , Devriendt C.
Published: May 2023

Curtailment is a known phenomenon for wind turbine operators of both onshore and offshore wind turbine generators (WTG). Curtailment refers to the situation in which the power output of all WTG’s within a windfarm is forced below the expected power output at the occurring environmental conditions. A direct consequence of curtailment is the loss of power production. In the present contribution further consequences of curtailment of an offshore wind farm (OWF) are studied from the perspective of the support structure, in specific the foundation. In relation to curtailment a couple of potentially critical operational conditions impacting the fatigue consumption of the support structure can be identified. Besides the standstill during operational windspeed conditions, in specific damaging for the +7MW generation WTG’s, curtailment introduces repeated transitions between operational conditions. Since transitions between operational conditions of a WTG are known to be a cause of high fatigue loads in the structural components of the WTG, their increased occurrence due to curtailment might also have an impact on the fatigue consumption of the support structure. With the growing interest of the industry to quantify and potentially optimize the structural lifetime consumption in view of potential lifetime extension of OWF assets, any potential fatigue damaging operational condition is to be investigated. The present work focusses on the investigation of the impact these transitional load cycles may have on the structural lifetime of the WTG foundation. To assess the impact on lifetime, the assessment of the damage equivalent loads (DEL) derived from structural health monitoring (SHM) data are used as a data-driven alternative for model-based load simulations. In the present work such data-driven lifetime assessment studies the impact of curtailment regimes with different frequency of stop and start cycles on the structural lifetime. The study is performed based on 1 year of SHM data collected from two OWF’s. The assessment demonstrates that the impact of additional transitional load cycles on the structural fatigue life consumption is to be considered when defining a long-term curtailment strategy for an OWF.
Wind resource modelling of entire sites using Large Eddy Simulation
Authors: Kantharaju Jahnavi , Storey Rupert , Julian Anatole , Delaunay Francois , Michaud Daniel
Published: May 2023

Accurate wind speed, direction, shear and turbulence information are key inputs for wind farm energy yield and turbine suitability assessment. Met-mast measurements offer limited coverage both in horizontal and vertical directions, with few locations on the site and heights typically limited to below turbine hub-height. Simulation becomes an increasingly appealing option to mitigate these shortcomings. Current flow models used in wind resource assessment (WRA) rely heavily on assumptions to simplify complex atmospheric physics and reduce computing expense. As a result, they cannot resolve turbulence, and output average or annualized statistics. A new generation of models utilizing high-performance-computing now allows for high-fidelity simulation of sites with fewer modelling assumptions. In this work, we demonstrate and validate a computationally feasible large eddy simulation (LES) approach to generate high-fidelity time series of relevant quantities for WRA - including resolved turbulence - at sites in the order of 1000 square kilometres. The capability of the LES to produce insights in complex terrain is presented. A validation of the approach is performed by comparison of raw model results against met-mast measurements in a wide range of sites with varied complexities. Results show good agreement with measurements, with further error reduction expected through downstream adjustment of the model results with met-mast data on sites. Overall, the approach enables high-fidelity time-series based modelling for wind resource characterization and value addition to the WRA tool chain.
Weather-dependent passive thermography and thermal simulation of in-service wind turbine blades
Authors: Chaudhuri Somsubhro , Stamm Michael , Krankenhagen Rainer
Published: May 2023

To cope with the increase in the manufacturing and operation of wind turbines, wind farm operators need inspection tools that are able to provide reliable information while keeping the downtime low. Current inspection techniques require the wind turbine to be stopped. This work presents the current progress in the project EvalTherm, in which passive thermography is evaluated as a possible non-destructive inspection tool for operational wind turbine blades (WTBs). A methodology to obtain thermal images of rotating WTBs has been established in this project. However, the quality of the results is heavily dependent on various aspects such as weather conditions, information on the inspected WTB, damage history, etc. In this work, a section of a used WTB is simulated using finite-element modelling (FEM) as well as experimentally tested for evaluating the accuracy of the model. Such a model will provide insight into the potential thermal response of a certain structure (with specific material properties) in given weather (boundary) conditions. The model is able to provide satisfactory predictions of the temporal thermal response of the structure, as well as indicate what thermal contrast(s) transients result from artificial defects introduced in the structure.
Analytical and MonteCarlo approaches to infer the total gamma ray emission from the JET tokamak
Authors: Marcer G. , Zohar A. , Dal Molin A. , Rigamonti D. , Rebai M. , Nocente M. , Panontin E. , Croci G. , Gorini G. , Grosso G. , Muraro A. , Perelli Cippo E. , Putignano O. , de la Luna E. , Ghani Z. , Conroy S. , Garcia J. , Kazakov Y. , Kiptily V. , Maslov M. , Nave M.F.F. , Ongena J. , Tardocchi M.
Published: May 2023

A single gamma-ray spectrometer installed at the end of a collimator can be
used to infer the total emission from a tokamak plasma if the transport of
gamma-rays from the plasma to the detector is known. In such analysis, the
plasma emission profile plays a fundamental role, since it impacts the
fraction of plasma volume intercepted by the detector line of sight.

In this work, the DT 17 MeV fusion gamma-rays emission profile of the
JET discharge #99608 from second 46 to 48 has been estimated
both with the TRANSP code and reconstructed through tomographic inversion
based on the neutron camera data, assuming that fusion gamma-rays
have the same profile as the 14 MeV fusion neutrons. The gamma-ray
transport has been evaluated both by MonteCarlo simulations and analytical
calculations.

By combining MonteCarlo and analytical evaluations of the gamma-ray transport
in different ways with the estimated radiation emission profile, we provide
four different routes to determine the total gamma-ray yield from
measurements whose results agree within better than 10%.
Bioprinted cancer-stromal in-vitro models in a decellularized ECM-based bioink exhibit progressive remodeling and maturation
Authors: Kort-Mascort Jacqueline , Shen Molly L , Martin Emma , Flores-Torres Salvador , Pardo Lucas Antonio , Siegel Peter M , Tran Simon D , Kinsella Joseph
Published: May 2023

Constant matrix remodeling and cellular heterogeneity in cancer are key contributors to its development and can profoundly alter treatment efficacy. Developing in-vitro models containing relevant features that can recapitulate these aspects of the tumor microenvironment and that are well characterized can circumvent the limitations of conventional 2D cultures and animal models. Automated fabrication methods combined with biomimetic biomaterials have provided the opportunity to create platforms that can potentially incorporate a heterogeneous population of cells in a 3D environment that allows cell–cell and cell-ECM interactions with reproducibility. This study used 3D extrusion bioprinting and a composite bioink containing a reinforced decellularized extracellular matrix (ECM) hydrogel to fabricate a head and neck cancer in-vitro model. The constituents of this model included fibroblasts and active ECM proteins to represent the stroma, along with HNSCC cells to represent the tumor component. The topographical characterization of the bioink showed a fibrous network with nanometer-sized pores. After cell encapsulation and model fabrication, we observed spheroid development and growth over time with cancer cells in the core and fibroblasts in the periphery. Our model is compatible with matrix metalloproteinase (MMP) quantification techniques and showed significant differences in the presence of MMP-9 and MMP-10 compared to the control groups. This characterized model is proposed as a tool for further translational and drug discovery applications since it provides a biomimetic scenario that allows the study of the tumor microenvironment in-vitro using nondestructive longitudinal monitoring over time.