bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of olive leaf on physicochemical parameters, antioxidant potential and phenolics of Ayvalik olive oils at two maturity stages
Authors: Kıralan Mustafa , Çengel Halil , Toptancı İsra , Ramadan Mohamed Fawzy
Published: July 2024

Ayvalik is an important and widely grown olive cultivar in Turkey. Olive fruits were harvested at two different harvesting periods, early and middle. Olive oils were extracted in an industrial two-phase continuous system with/without olive leaves at 2%, 4%, and 6% (w/w) concentrations. Oils were stored at room temperature and 12 °C in darkness. Basic quality parameters such as free fatty acids (FFA), peroxide value and absorbance values (K232 and K270) conformed to the European extra virgin olive oil standards. Besides, the fatty acid composition of samples was consistent with the values for extra virgin olive oil reported by the European Commission. Leaf addition enriched phenolic compounds, antiradical activity, oxidative stability, color parameters, and sensory characteristics of Ayvalik olive oils. During storage, the losses in phenolic compounds, color and sensory properties of the oils enriched by adding leaves were less than in the control sample. The sensory properties and phenolic composition of the cold-stored olive oils differed from those stored in the dark and at room conditions. Regarding positive sensory properties, the oils stored in the cold have less loss in their desired properties than those stored under room conditions. In addition, the breakdown of complex phenolic substances into simple phenolic substances such as tyrosol and hydroxytyrosol was found to be less in the samples stored at cold conditions. It has been shown that hydrolytic and oxidative changes occur less in cold storage.
Alimenter le parc demain
Authors: Terminet François
Published: July 2024

Si l’approvisionnement du parc nucléaire français ne pose pas d’enjeu à court terme, la question de son alimentation à plus long terme doit être anticipée. Les différents acteurs du nucléaire s’y emploient.
Green endoscopy, one step toward a sustainable future: Literature review
Authors: Maida Marcello , Vitello Alessandro , Shahini Endrit , Vassallo Roberto , Sinagra Emanuele , Pallio Socrate , Melita Giuseppinella , Ramai Daryl , Spadaccini Marco , Hassan Cesare , Facciorusso Antonio
Published: July 2024

Rapid climate change or climate crisis is one of the most serious emergencies of the 21st century, accounting for highly impactful and irreversible changes worldwide. Climate crisis can also affect the epidemiology and disease burden of gastrointestinal diseases because they have a connection with environmental factors and nutrition.

Gastrointestinal endoscopy is a highly intensive procedure with a significant contribution to greenhouse gas (GHG) emissions. Moreover, endoscopy is the third highest generator of waste in healthcare facilities with significant contributions to carbon footprint. The main sources of direct carbon emission in endoscopy are use of high-powered consumption devices (e.g. computers, anesthesia machines, wash machines for reprocessing, scope processors, and lighting) and waste production derived mainly from use of disposable devices. Indirect sources of emissions are those derived from heating and cooling of facilities, processing of histological samples, and transportation of patients and materials.

Consequently, sustainable endoscopy and climate change have been the focus of discussions between endoscopy providers and professional societies with the aim of taking action to reduce environmental impact. The term "green endoscopy" refers to the practice of gastroenterology that aims to raise awareness, assess, and reduce endoscopy´s environmental impact.

Nevertheless, while awareness has been growing, guidance about practical interventions to reduce the carbon footprint of gastrointestinal endoscopy are lacking. This review aims to summarize current data regarding the impact of endoscopy on GHG emissions and possible strategies to mitigate this phenomenon. Further, we aim to promote the evolution of a more sustainable "green endoscopy".
Visually navigated, ultrasound-guided, freehand percutaneous calyceal
puncture – preclinical evaluation of a novel device to simplify a complex
surgical task
Authors: Wakileh Gamal Anton , Hohmann Manuel , Rassweiler-Seyfried Marie Claire , Klein Jan Thorsten
Published: July 2024

Purpose Freehand sonographic percutaneous puncture techniques for the
renal calyceal system are on the rise. Much time and practice are required to
master this technique. Navigation-supported puncture aids could help make
percutaneous access easier and faster. The aim of this study was to determine
whether navigated puncture is feasible, and whether it is easier and faster
compared to the conventional sonographic procedure.

Materials & Methods We performed prospective free-hand percutaneous
puncture on a porcine kidney model embedded in gelatin using the Xperius
ultrasound system in combination with needle tracking with a Stimuplex Onvision
hollow needle, compared to the conventional freehand ultrasound puncture
technique. Punctures were performed by 25 participants using the ultrasound
machine with or without needle tracking mode.

Results Compared to the conventional approach, the navigated approach
reduced the number of puncture procedures by 0.2 attempts(8%) in the experienced
group. The time to calyx access was reduced by 15 seconds (26%). In the novice
group, navigated puncture required 1.2 fewer attempts (36%) and the time to
access was 70 seconds faster (61%).

Conclusion Puncture using the novel device is feasible. The number of
punctures and the time needed for successful access of the calyceal system was
reduced by use of navigation in both groups, although the trend was significant
only in the novice group. Navigation using needle tracking seems to help
beginners perform sonographic percutaneous puncture at a level similar to
experienced users. For a more precise analysis and validation, further studies
are needed.
Acid Treatment of FVIII-Containing Plasma Samples Unmasks a Broad Spectrum of FVIII-Specific Antibodies in ELISA
Authors: Schmidt Anja , Stichel Diana , Salzmann-Manrique Emilia , Königs Christoph
Published: July 2024

During routine treatment, plasma samples of patients with hemophilia A or acquired hemophilia A are frequently analyzed for the presence of FVIII-specific antibodies. While only inhibitory antibodies can be detected by the Bethesda assay, inhibitory and non-inhibitory antibodies can be detected by ELISA. However, plasma samples of patients frequently contain endogenous or substituted FVIII, hence interfering with both types of analyses. One option for the inactivation of FVIII is heat denaturation, which unfortunately has been shown to lead to high background signals complicating the discrimination of negative and positive plasma samples. In the current study, we developed a method of acid denaturation for FVIII-containing plasma samples that can help identify samples containing FVIII-specific antibodies and compared the effects of heat and acid denaturation on the detection of FVIII–antibody interactions in a monoclonal setting. The aim of our study was to establish an analysis that allows safer treatment decisions in the context of tolerance to FVIII.
Venous Thromboembolism Post-allogeneic Hematopoietic Cell Transplant: Risk Factors, Incidence, and Outcomes
Authors: Granat Lauren M. , Li Hong , Ondeck Mariah , Osantowski Bennet , Peysin Chana , Wilks Mailey , Ferraro Christina , Sobecks Ronald , Angelini Dana , Hamilton Betty K.
Published: July 2024

Background Venous thromboembolism (VTE) is a well-documented complication of both solid and hematologic malignancies, but there are fewer data on allogeneic hematopoietic cell transplant (HCT) recipients. Therefore, we studied the incidence, risk factors, and impact of VTE on post-HCT outcomes in a contemporary cohort.

Methods We retrospectively reviewed patients who underwent allogeneic HCT between January 2014 and August 2019 to identify patients with post-HCT VTE. Patient, disease, and transplant-related risk factors for VTE were investigated using competing risk analysis.

Results A total of 431 patients were included in this study. Median (interquartile range [IQR]) age in years was 59 (46–65) at transplant. The most common indication for transplant was acute myelogenous leukemia (49.4%). Within our cohort, 64 patients (14.8%) developed post-HCT VTE with a median (IQR) follow-up time of 24.6 (8.4–47.1) months. The cumulative incidence of VTE was 4.2% at 6 months, 9.0% at 12 months, 12.6% at 24 months, and 13.8% at 36 months. In multivariable analysis, older age (hazard ratio [HR] per 10-year increase: 1.36, 95% confidence interval [CI]: 1.09–1.70), history of VTE (HR: 1.95, 95% CI: 1.09–3.49), and grade 2–4 acute graft versus host disease (GVHD; HR: 1.75, 95% CI: 1.05–2.94) were independently associated with VTE. VTE was significantly associated with an increased risk of nonrelapse mortality (NRM; HR: 4.09, 95% CI: 2.47–6.74) and decreased overall survival (OS; HR: 2.19, 95% CI: 1.48–3.24).

Conclusion VTE is an important complication after allogeneic HCT and is significantly associated with increased NRM and decreased OS. Older patients, those with prior VTE, and patients with acute GVHD are at increased risk for development of VTE after HCT.
Efficacy and safety of a single-use cholangioscope for percutaneous transhepatic cholangioscopy
Authors: Boskoski Ivo , Beyna Torsten , Lau James YW , Lemmers Arnaud , Fotoohi Mehran , Ramchandani Mohan , Pontecorvi Valerio , Peetermans Joyce , Shlomovitz Eran
Published: July 2024

Background and study aims Percutaneous transhepatic
cholangioscopy (PTCS) is a management option for patients in whom peroral cholangioscopy or
endoscopic retrograde cholangiopancreatography (ERCP) fail. We conducted a case series on the
efficacy and safety of PTCS using a cholangiopancreatoscope cleared by the US Food and Drug
Administration in 2020.

Patients and methods Fifty adult patients scheduled for PTCS or other cholangioscopic procedure were enrolled at seven academic medical centers and followed for 30 days after the index procedure. The primary efficacy endpoint was achievement of clinical intent by 30 days after the index PTCS procedure. Secondary endpoints included technical success, procedure time, endoscopist ratings of device attributes on a scale of 1 to 10 (best), and serious adverse events (SAEs) related to the device or procedure.

Results Patients had a mean age of 64.7±15.9 years, and 60.0% (30/50) were male. Forty-four patients (88.0%) achieved clinical intent by 30 days post-procedure. The most common reasons for the percutaneous approach were past (38.0%) or anticipated (30.0%) failed ERCP. The technical success rate was 96.0% (48/50), with a mean procedure time of 37.6 minutes (SD, 25.1; range 5.0–125.0). The endoscopist rated the overall ability of the cholangioscope to complete the procedure as a mean 9.2 (SD, 1.6; range 1.0–10.0). Two patients (4.0%) experienced related SAEs, one of whom had a fatal periprocedure aspiration.

Conclusions PTCS is an important endoscopic option for selected patients with impossible retrograde access or in whom ERCP fails. Because of the associated risk, this technique should be practiced by highly trained endoscopists at high-volume centers. (ClinicalTrials.gov number, NCT04580940)
Endoscopic ultrasound with tissue acquisition of lymph nodes in patients with potentially resectable intrahepatic cholangiocarcinoma
Authors: de Jong David M. , Van Driel Lydi M.J.W. , Groot Koerkamp Bas , van de Vondervoort Sanne , Dwarkasing Roy S. , Thomeer Maarten G.J. , Doukas Michael , Voermans Rogier P. , Verdonk Robert C. , Polak Wojciech G. , de Jonge Jeroen , Bruno Marco J.
Published: July 2024

Background and study aims Lymph node (LN) involvement is a poor prognostic factor for patients with intrahepatic cholangiocarcinoma (iCCA). The aim of this study was to evaluate the yield and impact on clinical decision making of endoscopic ultrasound with tissue acquisition (EUS-TA) of LNs in patients with potentially resectable iCCA.

Patients and methods In this multicenter cohort study, patients with potentially resectable iCCA and preoperative EUS between 2010 and 2020 were retrospectively included. The impact of EUS-TA was defined as the percentage of patients who did not undergo surgical exploration due to pathologically confirmed positive LNs found with EUS-TA.

Results A total of 56 patients underwent EUS, with 91% of patients to target suspicious LNs on imaging. EUS-TA of LNs confirmed malignancy in 21 LNs among 19 patients (34%). In 17 patients (30%), surgical exploration was withheld due to nodal involvement. Finally, 24 patients (43%) underwent surgical exploration among whom positive regional LNs were identified in six patients (25%).

Conclusions In patients with potentially resectable iCCA and suspicious LNs on cross-sectional imaging, EUS-TA confirmed LN involvement in 30% of patients. Surgical exploration was withheld mostly because of extraregional LN involvement and regional LN involvement in patients with high surgical risk.
Plug-Assisted Retrograde Transvenous Obliteration: A Modified Balloon-Occluded Retrograde Transvenous Obliteration of Gastric Varices
Authors: Gwon Dong Il , Yoon Hyun-Ki
Published: July 2024

Gastric varices (GVs) and hepatic encephalopathy (HE) are major complications of portal hypertension in patients with liver cirrhosis. As most of the GVs drain into the left renal vein via a portosystemic shunt, the concept of retrograde treatment approach such as balloon-occluded retrograde transvenous obliteration using sclerosing agents has been introduced. Recently, plug-assisted retrograde transvenous obliteration (PARTO) has been alternatively performed, which uses vascular plug and gelfoam. PARTO utilizes a permanent vascular plug to reduce postprocedural monitoring time as well as to avoid the risk of balloon rupture–related complications. It also eliminates the sclerosing agents–related complications with the use of gelfoam as an embolics. In this review, we introduce technical aspects of PARTO and outline its potential for use as the treatment of GVs and HE.
Computational experiments with cellular-automata generated images reveal intrinsic limitations of convolutional neural networks on pattern recognition tasks
Authors: Lei Weihua , Zanchettin Cleber , Santos Flávio A. O. , Nunes Amaral Luís A.
Published: July 2024

The extraordinary success of convolutional neural networks (CNNs) in various computer vision tasks has revitalized the field of artificial intelligence. The out-sized expectations created by this extraordinary success have, however, been tempered by a recognition of CNNs’ fragility. Importantly, the magnitude of the problem is unclear due to a lack of rigorous benchmark datasets. Here, we propose a solution to the benchmarking problem that reveals the extent of the vulnerabilities of CNNs and of the methods used to provide interpretability to their predictions. We employ cellular automata (CA) to generate images with rigorously controllable characteristics. CA allow for the definition of both extraordinarily simple and highly complex discrete functions and allow for the generation of boundless datasets of images without repeats. In this work, we systematically investigate the fragility and interpretability of the three popular CNN architectures using CA-generated datasets. We find a sharp transition from a learnable phase to an unlearnable phase as the latent space entropy of the discrete CA functions increases. Furthermore, we demonstrate that shortcut learning is an inherent trait of CNNs. Given a dataset with an easy-to-learn and strongly predictive pattern, CNN will consistently learn the shortcut even if the pattern occurs only on a small fraction of the image. Finally, we show that widely used attribution methods aiming to add interpretability to CNN outputs are strongly CNN-architecture specific and vary widely in their ability to identify input regions of high importance to the model. Our results provide significant insight into the limitations of both CNNs and the approaches developed to add interpretability to their predictions and raise concerns about the types of tasks that should be entrusted to them.
Time-bin entanglement in the deterministic generation of linear photonic cluster states
Authors: Bauch David , Köcher Nikolas , Heinisch Nils , Schumacher Stefan
Published: July 2024

We theoretically investigate strategies for the deterministic creation of trains of time-bin entangled photons using an individual quantum emitter described by a Λ-type electronic system. We explicitly demonstrate the theoretical generation of linear cluster states with substantial numbers of entangled photonic qubits in full microscopic numerical simulations. The underlying scheme is based on the manipulation of ground state coherences through precise optical driving. One important finding is that the most easily accessible quality metrics, the achievable rotation fidelities, fall short in assessing the actual quantum correlations of the emitted photons in the face of losses. To address this, we explicitly calculate stabilizer generator expectation values as a superior gauge for the quantum properties of the generated many-photon state. With widespread applicability in other emitter and excitation–emission schemes also, our work lays the conceptual foundations for an in-depth practical analysis of time-bin entanglement based on full numerical simulations with predictive capabilities for realistic systems and setups, including losses and imperfections. The specific results shown in the present work illustrate that with controlled minimization of losses and realistic system parameters for quantum-dot type systems, useful linear cluster states of significant lengths can be generated in the calculations, discussing the possibility of scalability for quantum information processing endeavors.
Ultra-high precision comb-locked terahertz frequency-domain spectroscopy of whispering-gallery modes
Authors: Müller Sebastian , Hill Kane , Vogt Dominik Walter , Puppe Thomas A. , Mayzlin Yuriy , Wilk Rafal
Published: July 2024

We demonstrate the capabilities of a novel frequency-domain terahertz spectrometer based on a comb-locked frequency synthesizer, which provides absolute frequency calibration. The inherent stability and repeatability of the scans allow for the combination of fast data acquisition with an average time-limited signal-to-noise ratio. We demonstrate kilohertz level frequency resolution in terahertz precision spectroscopy of ultra-high quality whispering-gallery-mode resonators. Spectra covering multiple free spectral ranges (>36 GHz) with sub-20 kHz resolution are acquired in 5 s. We analyze the coupling behavior and temperature tuning of single resonances and, for the first time, observe minute red and blue shifts of different mode families. The experimental results are supported with finite element simulations.
Occurrence and trends of historical tropical cyclone rainfall on near-coastal regions of Australia
Authors: Bell Samuel , Dowdy Andrew , Chand Savin , Su Chun-Hsu
Published: July 2024

Extreme rainfall driven by tropical cyclones (TCs) has profound effects on Australian coastlines at both local and regional scales. Here, we develop methods for comparing TC-driven widespread and localised rainfall on three broad coastal regions of tropical Australia (west, north and east). Trends, average recurrence intervals (ARIs) and the fractional contribution of TC rainfall are explored in three historical datasets: Australian Gridded Climate Data (AGCD), ECMWF Reanalysis (ver. 5, ERA5) and the Bureau of Meteorology Atmospheric high resolution Regional Reanalysis for Australia (ver. 1, BARRA1). Results for trends and ARIs between the different datasets are generally inconsistent and also differ between regions, partially owing to the short-term temporal records of some of the data as well as inconsistencies in extreme values between datasets. By contrast, there is a general agreement between all datasets on the fractional contribution of TC rainfall, signalling an increase in recent years. This result is considered together with the trend towards fewer TCs occurring in this region over recent decades, indicating a trend towards increased rainfall intensity per TC on average, assuming steady landfall rates. The methods developed here can be applied easily to other data types such as regional climate model experiments, facilitating a multiple lines of evidence approach that incorporates both observational-based and model-based data. This research is intended to help provide new methods and guidance for identifying trends in TC-driven extreme rainfall, relevant for enhanced planning and adaptation to the impacts of these extreme weather systems.
Actions chains and intention understanding in 3- to 6-year-old children
Authors: Di Dio Cinzia , Miraglia Laura , Peretti Giulia , Marchetti Antonella , Rizzolatti Giacomo
Published: July 2024

In intentional behavior, the final goal of an action is crucial in determining the entire sequence of motor acts. Neurons have been described in the inferior parietal lobule of monkeys, which besides encoding a specific motor act (e.g., grasping), have their discharge modulated by the final goal of the intended action (e.g., grasping-to-eat). Many of these “action-constrained” neurons have mirror properties responding to the observation of the motor act they encode, provided that this is embedded in a specific action. Thanks to this mechanism, the observers have an internal copy of the whole action before its execution and may, in this way, understand the agent’s intention. The chained organization of motor acts has been demonstrated in schoolchildren. Here, we examined whether this organization is already present in very young children. To this purpose, we recorded EMG from the mylohyoid (MH) muscle in the children aged 3 to 6 y. The results showed that preschoolers, like older children, possess the chained organization of motor acts in execution. Interestingly, in comparison to older children, they have a delayed ability to use this mechanism to infer others’ intentions by observation. Finally, we found a significant negative association between the children’s age and the activation of the MH muscle during the grasp-to-eat phase in the observation condition. We, tentatively, interpreted it as a sign of an immature control of motor acts.
Tropism for ciliated cells is the dominant driver of influenza viral burst size in the human airway
Authors: Roach Shanley N. , Shepherd Frances K. , Mickelson Clayton K. , Fiege Jessica K. , Thielen Beth K. , Pross Lauren M. , Sanders Autumn E. , Mitchell Jason S. , Robertson Mason , Fife Brian T. , Langlois Ryan A.
Published: July 2024

Influenza viruses pose a significant burden on global human health. Influenza has a broad cellular tropism in the airway, but how infection of different epithelial cell types impacts replication kinetics and burden in the airways is not fully understood. Using primary human airway cultures, which recapitulate the diverse epithelial cell landscape of the human airways, we investigated the impact of cell type composition on virus tropism and replication kinetics. Cultures were highly diverse across multiple donors and 30 independent differentiation conditions and supported a range of influenza replication. Although many cell types were susceptible to influenza, ciliated and secretory cells were predominantly infected. Despite the strong tropism preference for secretory and ciliated cells, which consistently make up 75% or more of infected cells, only ciliated cells were associated with increased virus production. Surprisingly, infected secretory cells were associated with overall reduced virus output. The disparate response and contribution to influenza virus production could be due to different pro- and antiviral interferon-stimulated gene signatures between ciliated and secretory populations, which were interrogated with single-cell RNA sequencing. These data highlight the heterogeneous outcomes of influenza virus infections in the complex cellular environment of the human airway and the disparate impacts of infected cell identity on multiround burst size, even among preferentially infected cell types.
A peak enhancement of frequency response of waveguide integrated silicon-based germanium avalanche photodetector
Authors: Yi Linkai , Liu Daoqun , Cheng Wenzheng , Li Daimo , Zhou Guoqi , Zhang Peng , Tang Bo , Li Bin , Wang Wenwu , Yang Yan , Li Zhihua
Published: July 2024

Avalanche photodetectors (APDs) featuring an avalanche multiplication region are vital for reaching high sensitivity and responsivity in optical transceivers. Waveguide-coupled Ge-on-Si separate absorption, charge, and multiplication (SACM) APDs are popular due to their straightforward fabrication process, low optical propagation loss, and high detection sensitivity in optical communications. This paper introduces a lateral SACM Ge-on-Si APD on a silicon-on-insulator (SOI) wafer, featuring a 10 μm-long, 0.5 μm-wide Ge layer at 1310 nm on a standard 8-inch silicon photonics platform. The dark current measures approximately 38.6 μA at −21 V, indicating a breakdown voltage greater than −21 V for the device. The APDs exhibit a unit-gain responsivity of 0.5 A/W at −10 V. At −15 V, their responsivity reaches 2.98 and 2.91 A/W with input powers of −10 and −25 dBm, respectively. The device's 3-dB bandwidth is 15 GHz with an input power of −15 dBm and a gain is 11.68. Experimental results show a peak in impedance at high bias voltages, attributed to inductor and capacitor (LC) circuit resonance, enhancing frequency response. Furthermore, 20 Gbps eye diagrams at −21 V and −9 dBm input power reveal signal to noise ratio (SNRs) of 5.30. This lateral SACM APD, compatible with the stand complementary metal oxide semiconductor (CMOS) process, shows that utilizing the peaking effect at low optical power increases bandwidth.
High-precision X-ray characterization for basic materials in modern high-end integrated circuit
Authors: Zhao Weiran , Mo Qiuqi , Zheng Li , Li Zhongliang , Zhang Xiaowei , Yu Yuehui
Published: July 2024

Semiconductor materials exemplify humanity's unwavering pursuit of enhanced performance, efficiency, and functionality in electronic devices. From its early iterations to the advanced variants of today, this field has undergone an extraordinary evolution. As the reliability requirements of integrated circuits continue to increase, the industry is placing greater emphasis on the crystal qualities. Consequently, conducting a range of characterization tests on the crystals has become necessary. This paper will examine the correlation between crystal quality, device performance, and production yield, emphasizing the significance of crystal characterization tests and the important role of high-precision synchrotron radiation X-ray topography characterization in semiconductor analysis. Finally, we will cover the specific applications of synchrotron radiation characterization in the development of semiconductor materials.
Analytical solution for optimal protocols of weak drivings
Authors: Nazé Pierre
Published: July 2024

One of the main objectives of science is the recognition of a general pattern in a particular phenomenon in some particular regime. In this work, this is achieved with the analytical expression for the optimal protocol that minimizes the thermodynamic work and its variance for finite-time, isothermal, and weak processes. The method that solves the Euler–Lagrange integral equation is quite general and depends only on the time-reversal symmetry of the optimal protocol, which is proven generically for the regime considered. The solution is composed of a straight line with jumps at the boundaries and impulse-like terms. Already known results are deduced, and many new examples are solved corroborating this pattern. Slowly-varying and sudden cases are deduced in their appropriate asymptotic limits. Comparison with numerical procedures is limited by the nonavailability of the present methods of the literature to produce solutions in the space of distributions.
Study of heat transfer in heated garments based on the JOS-3 model
Authors: Yu Tao , Ou Meilian
Published: July 2024

Body temperature prediction and control are important in cold environments or extreme temperatures. In this paper, a multi-segmented heated garment model based on J0S-3 thermoregulation is proposed, and the effects of multi-layer garments and air interlayers on human heat transfer are explored, as well as the role of heating pads in the heat transfer path. By comparison, the simulation results of the present study were found to align with the temperature change curves observed in available experimental data. Moreover, the root mean square of the overall core temperature and the root mean square of the skin temperature were both below 0.08°C and 0.36°C, respectively, which provided good prediction results. This study helps people to adapt to the environment with variable temperatures and has a great potential for development in body temperature prediction technology and application.
Characterization of gas explosion shock wave propagation in long straight confined space
Authors: Huang Chaoyuan , Liu Fei , Xin Kai , Gao Yonghong , Zhou Liqiang , Wu Hao , Duan Yapeng
Published: July 2024

Currently, China is engaged in the construction of urban subterranean areas and the deployment of gas pipelines within these spaces. Nonetheless, the entry of gas into subterranean areas poses a definite threat of leaks and explosions. An explosion triggered by a gas pipeline leak will gravely compromise the underground space’s integrity and significantly affect nearby structures. Consequently, examining the spread properties of gas explosion shock waves in urban subterranean areas is essential. This document utilizes FLACS software to develop an extensive straight confined space gas explosion model, examining the load properties of gas explosion shock waves and deriving the propagation law and distribution patterns of blast shock wave loads across various methane volumes. Gas explosion tests confirm the precision of the numerical model. Findings from the study can supply data on load for comparable safety assessments in underground spaces, enhancing their resilience to explosions.
Numerical simulation of structural optimization within a supersonic cyclone separator
Authors: Zhai Zhenhua , Chen Guanghui , Di Chuanjun , Zhang Lehui
Published: July 2024

Supersonic cyclone separation technology, as a new type of natural gas dewatering technology, utilizes the temperature drop generated by ultrahigh velocity fluid flow to condense the water vapor, thus accomplishing the goal of gas-liquid separation. At the input pressure of 8.48×104 Pa (G), the input temperature of 279.6 K, and the input water steam quality score of 5%, the flow fields and condensation characteristics were compared within the steeped, attached, five-curved three separator structures and the control group without the separator structure. The result shows that when the number of mahs of the ultrasonic spin separator of the ladder separator structure reached 1.51, the minimum pressure is −7.49×104 Pa, resulting in a temperature drop of approximately 100 K, and the flow field is most conducive to droplet condensation and growth; the maximum nucleation rate is 2.23×1023 kg−1·s−1, and the droplet diameter is 6.64×10−3μm.
Study on the body type of shaft spillway
Authors: Yang Shaojia , Liu Xiaoyu , Wang Jinfeng , Zhu Hongbo
Published: July 2024

In this paper, the influence of shaft spillway shape on its performance is studied by numerical simulation to improve its design and operation efficiency. The type of pressure slope section, the sensitivity of the radius of the turning section, and the optimal arrangement of the stilling pool are studied and analyzed. It is found that increasing the length of the pressure slope section can stabilize the flow in the pressure section of the tunnel. The deflection phenomenon can be reduced by increasing the radius of the turning section. The symmetrical arrangement of the stilling pool can improve the water flow pattern. Through numerical simulation, the paper provides some suggestions on the optimal design of the shaft spillway to improve its performance and efficiency.
Optimization of deep acid fracturing parameters for Shunbei carbonate dissolved fault reservoirs
Authors: Chao Xunsheng , Guan Chencheng , Xin Shunyuan , Ren Jichuan , Xu Peixuan
Published: July 2024

When encountering favorable reservoirs that have not been drilled along the wellbore trajectory of Shunbei carbonate fracture-cavity reservoirs, deep acid fracturing technology is required to communicate with favorable reservoirs and achieve production. Currently, there is no optimized method for designing deep acid fracturing parameters for Shunbei fracture-cavity reservoirs, which results in problems such as failure to communicate with favorable reservoirs after deep acid fracturing or rapid decline in production after communication. To address these issues, this paper establishes a geological feature model for fracture-cavity reservoirs based on the characteristics of Shunbei fracture-cavity reservoirs and proposes a deep acid fracturing fracture parameter optimization approach with production capacity as the goal. Using a multi-field coupled acid fracturing model that can reflect the large leakage characteristics of fracture-cavity reservoirs, the proposed fracture parameters are used to simulate and optimize the scale of pre-flushing liquid and acid liquid. The simulation results show that the desired increase in production can be achieved when the fracture diversion capacity is 30D·cm and the penetration ratio is between 0.1 and 0.3. Furthermore, this paper recommends injecting 450~900 m3 of pre-flushing liquid to communicate with favorable reservoirs (0.1≤De≤0.2), followed by the injection of 900 m3 of cross-linked acid and 450 m3 of gelled acid to construct the fracture diversion capacity through acid corrosion.
Numerical simulation analysis of the influence of karst cave orientation and surrounding rock properties on tunnel excavation
Authors: Tao Xinhua , Gan Fan , Yu Jiang , Huang Linchong , Chen Yu
Published: July 2024

The underground distribution of complex karst geology in the Zhangjiajie region of China poses a significant threat to the construction safety of tunnels, not only increasing project investments but also severely impacting the stable operation of engineering construction. This paper, based on ABAQUS numerical simulation, explores the influence of karst caves around tunnels in different orientations of surrounding rock environments through the rock strength, stress field, and dimension of surrounding rock mass. The results are as follows: (1) With the decrease in cohesive strength of the cave surrounding rock, the stability of the tunnel is enhanced. (2) The maximum displacement of the lower cave is 0.02011 m, greater than that of the side cave, which is 0.01965 m; the maximum principal stress of the lower cave is 7.457 MPa, greater than that of the side cave, which is 7.423 MPa. The lower cave has a greater impact on tunnel construction and can further reduce the stability of the karst tunnel surrounding rock. This paper has researched the influence of caves on tunneling through surrounding rock and investigated the effects of cave orientation, cohesive strength, and other parameters on tunnel construction. It provides theoretical guidance for tunnel alignment and pre-processing of concealed caves.
Study on the spectrum model of light response of Manglietia yuyuanensis
Authors: Guo Jian , Guo Yong , Wang Hong , Huang Chenying , Lin Huoyang
Published: July 2024

To study the spectral characteristics of the photosynthetic response of Manglietia yuyuanensis, this paper uses a self-developed monochromatic light generator to generate 22 kinds of monochromatic light, and measures the net photosynthetic rate of Manglietia yuyuanensis under the irradiation of 22 kinds of monochromatic light, then obtains its light response curve under different wavelengths. The right-angle hyperbolic correction model was used to fit the light response curves under each kind of monochromatic light, and the completed spectrum of the light saturation points of Manglietia yuyuanensis was obtained. It makes up for the disadvantage that the self-developed monochromatic light generator cannot detect the light saturation point of the plant under some monochromatic light due to the low radiation intensity. This paper supposes that the coefficients α, β, γ, and Rd in the right-angle hyperbolic correction model are functions related to the wavelength λ, then fits a Gaussian function of α, β, γ, and Rd to wavelength λ. From the fitting results, the fitting degree of α, β, and γ can reach 0.8 or more, which indicates the fitting effect is good. The fitting degree of Rd is about 0.5. According to the fitting function, a new photosynthesis model related to wavelength and light radiation was obtained, and the fitting degree of the data by the new model is good, laying a foundation for future research on photosynthetic response curves of other plants.
Study on applicability of mathematical model of pipe-soil interaction
Authors: Hou Yu , Liu Yuqing , Sun Chao , Zhang Zhenyong , Kong Tianwei , Wu Xiatong , Yang Zhaohan , Huang Wei , Liu Xiaoben
Published: July 2024

The applicability of the soil spring calculation model given in China’s standard SY/T 7403 “Code for strain-based design of oil & gas transmission pipelines” and GB/T 50470 “Seismic technical code for oil and gas transmission pipeline engineering” to large-diameter pipelines is not clear. In this paper, the soil spring calculation formulas recommended in the two standards are analyzed, and the corresponding finite element numerical simulation models are established. The applicability of the lateral and vertical soil spring models in the two standards is discussed. The results show that the calculation accuracy of the two standards needs to be improved, and the applicability is different for different pipe diameters and soil properties.
Study on the influence of selective laser melting temperature on the melting bath
Authors: Luo Wei , Hui Jizhuang , Wang Junjie , Yan Zhiqiang
Published: July 2024

The high-temperature gradient and high-frequency thermal cycling during the selective laser melting process will seriously affect the melting bath morphology and dimensions, which in turn affects the quality of formed parts. In this paper, a numerical model of the SLM process is established to emulate the temperature field and investigate temperature variation of single-layer and multi-channel models, as well as the influence of disparate laser power, hatch spacing, and scanning speed on melting baths. The simulation results show that the temperature gradient at the front end of the melting bath is small due to physical phase transition, and the temperature gradient nearer to the end of the melting bath is bigger. The midpoint of the second melting channel has the highest peak temperature due to heat conduction and accumulation; the impact of each technological parameter on the melting bath is in the following order: laser power > scanning speed > hatch spacing. Therefore, it is clear that the temperature distribution will provide a theoretical foundation for regulating the stress state of molded parts and ensuring the surface quality and mechanical capacity of the processed component.
Establishment and analysis of a unified mathematical model of kinematics and dynamics of flexible parallel mechanisms
Authors: Wang Jin , Jing Zijian , Guo Junli , Qin Tao , Li Han , Li Xin , Li Zhenchuang , Meng Fanhui , Qi Bo
Published: July 2024

The conventional positive solution approach for determining the forward motion of the kinematic mechanism relies primarily on the outcomes of the inverse solution of motion, which is not universally applicable to flexible parallel mechanisms. Furthermore, the process of analyzing the natural frequency of parallel mechanisms is complex, cumbersome, and challenging. More importantly, the two models are independent, and there is no unified mathematical analysis model for flexible parallel mechanisms. Therefore, this paper establishes a unified mathematical model for kinematics and dynamics analysis of flexible parallel mechanisms through an improved multi-body system transfer matrix method. Taking the flexible 3-RPU planar mechanism and the space 2-RPU (2-UPS) space mechanism as examples, respectively, the forward motion solution of the mechanism was analyzed and its working space range and resonance frequency were solved. Finally, the calculation results are compared with the simulation results, and the feasibility and accuracy of the method are proved. Through this method, we can quickly solve the motion characteristics of the mechanism without relying on the results of the inverse solution of the mechanism, which provides suggestions for the precise control of flexible parallel mechanisms and also provides corresponding reference basis for the practical application of flexible parallel mechanisms.
Numerical simulation of the effects of toothed structure on the flow boiling characteristics of micro-fin tubes
Authors: Lu Yongshuai , Cui Yunfang
Published: July 2024

The numerical simulation of R141b flow boiling in micro-fin tubes (MFTs) with a 1 mm equivalent diameter is conducted using the VOF and the Lee models. An analysis of the boiling heat transfer (HT) characteristics has been performed, considering impacts of the four factors. The most suitable correlation of boiling HT has also been evaluated. The summarized findings are as follows: the BHT coefficient within the MFTs consistently rises with increased mass velocity, heat flux, and saturation temperature. However, there is a presence of a partially dry-out region inside the MFTs at high heat flux. Additionally, the enhancement of boiling HT by elevating saturation temperature is not prominent in the low vapor quality range. HT coefficients of the MFTs with various fin structures ranked in magnitude are as follows: tapered MFTs > trapezoidal MFTs > circular MFTs. The model proposed by Wu is identified as the best predictor for flow boiling HT performance in horizontal MFTs, although its prediction accuracy is limited in the low vapor quality range.
Numerical simulation of control rod ejection velocity in a projectile rod accident based on STAR-CCM+
Authors: Kong Fanfu , Cai Ruhua , Luo Qingsong , Li Shujie , Xu Huaijin
Published: July 2024

To simulate and analyze the control rod ejection time in the process of reactor bomb rod accidents, the design input of bomb rod accident safety analysis is made. In this study, STAR-CCM+ simulation software was used to simulate the pressure field and velocity field in the process of high temperature and high-pressure liquid injection after the CRDM pressure casing was broken, and the ejection time of the control rod under different lifting forces was obtained comprehensively. At the same time, the simulation results are compared with the theoretical calculation results. The pop-out time of the control rod is about 0.1 s. Therefore, the results calculated by the simulation model established in this study can be used as the design input for the safety analysis of the projectile rod accident.
Theoretical and simulation study on the vibration modes of shear walls in prefabricated modular construction
Authors: Kong Va , Wang Xiaoguang , Wang Qiong , Li Zhen , Chen Hongbing , Wang Jiang
Published: July 2024

As prefabricated construction advances, the enhanced informatization and the industrialized modular construction method of MIC (Modular integrated construction) shear walls have been widely applied in real projects. MIC shear walls are generally made up of prefabricated wall modules with varying strength grades, using concrete of various ages, and are combined with cast-in-place concrete. Due to the unique construction requirements of these walls, defects such as interfacial delamination and internal voids might occur, arising from factors like concrete shrinkage and creep, complex interfacial structures, inadequate compaction during vibration, and construction process issues. Since these interfacial defects cannot be visually inspected from the exterior, developing non-destructive testing (NDT) methods specifically for detecting such defects in shear walls becomes an urgent necessity. This paper utilizes a combination of theoretical analysis and numerical simulation to explore the vibration modes of MIC shear walls with hidden defects. First, a theoretical model is proposed for the local vibration modes of MIC shear wall shells with consideration of interfacial delamination defects. Then, a numerical simulation model is established based on MIC shear wall construction and defect features to simulate the vibration behavior accurately. Finally, after examining the theoretical and simulated vibration characteristics of MIC shear walls, a significant theoretical foundation is established for identifying interfacial defects in MIC shear walls.
Study on the sound radiation characteristics of polygonal wear wheels of CRH3 high-speed train
Authors: Zhang Yaning , Zhang Xiaoan
Published: July 2024

Due to the increase in train operating speed, the phenomenon of collision vibration between wheels and rails becomes more and more obvious, and the degree of wheel wear increases dramatically. As a result, the wheel-rail noise problem has become more and more complex. The wheel polygonal wear is also widespread on the train. For the wheel in the form of polygonal wear of the wheel-rail vertical force, combined with the principle of wheel-rail noise, we conduct an in-depth study. An aerodynamic mutual coupling model for CRH3 high-speed vehicles is proposed. The role of the amplitude of 0.03 mm, i.e., the twentieth-order polygonal abrasion rate on the wheel-rail force is analyzed at the speed class of 200~350 km/h, and the acoustic radiation characteristics of the wheels are investigated at different speed classes. The results show that under different speed classes, when the wheel polygon order is in the twentieth order, the wheel-rail vertical force rises with the increase of speed, and the wheel sound power is also affected by a great change. There is a significant increase in the sound power from the low frequency of 20 Hz to 100 Hz and a peak in the mid-frequency up to 1, 000 Hz. Secondly, when the wheel radiated sound pressure levels at different speed levels, significant changes also occurred, with the sound pressure reaching a maximum of 110 dB at 350 km/h.
Design and implementation of a collaborative modeling architecture based on MDE (Multi-DDS Edge)
Authors: Zhang Songning , Guan Zheng , Ci Yan , Ding Gangyi
Published: July 2024

Virtual space is an integral part of the Metaverse. Typical virtual spaces are modeled step by step using artificial means. With the development needs of Metaverse modeling and simulation technology and the need for simulation fidelity and content richness in virtual space construction, efficient and correct modeling methods are required. It has become a bottleneck restricting the efficiency of virtual space modeling. This paper designs a multi-person collaborative virtual space modeling method, which improves the modeling efficiency, communication security, and interaction stability of the virtual space collaborative modeling method. Compared with existing collaborative modeling methods, this paper proposes a virtual space collaborative modeling method based on multi-edge DDS technology. By constructing MDE (multi-DDS edges) and MDE on user migration, collaborative construction in multiple virtual spaces is completed. Model data communication extends collaborative modeling technology from the virtual space creation stage to the virtual space simulation and deduction stage, and designs and verifies collaborative content, collaborative architecture, and collaborative communication. Experiments show that the architecture synergy efficiency is 145.6%, the architecture synergy efficiency is 212.5%, and the architecture synergy efficiency is 105.4%. As the number of people in collaborative modeling increases, the operational complexity and demonstration take a logarithmic form, meeting the needs of the future development of the metaverse.