bluuebunny/crossref_metadata_2025 huggingface dataset:
Detecting Strain Effects Due to Nanobubbles in Graphene Mach–Zehnder Interferometers
Authors: Myoung Nojoon , Song Taegeun , Park Hee Chul
Published: January 2024

Herein, the effect of elastic strain on a Mach–Zehnder (MZ) interferometer created by graphene p–n junction in quantum Hall regime is investigated. It is demonstrated that a Gaussian‐shaped nanobubble causes detuning of the quantum Hall conductance oscillations across the p–n junction, due to the strain‐induced local pseudo‐magnetic fields (PMFs). By performing a machine‐learning‐based Fourier analysis, the nanobubble‐induced Fourier component from the conductance oscillations originating from the external magnetic fields is differentiated. It is shown that the detuning of the conductance oscillations is due to the altered pathway of quantum Hall interface channels caused by the strain‐induced PMFs. In the presence of the nanobubble, a new Fourier component for a magnetic flux appears, and the corresponding MZ interferometry indicates that the enclosed area is reduced by half due to the strain‐mediated pathway between two quantum Hall interface channels. In the findings, the potential of using graphene as a strain sensor is suggested for developments in graphene‐based device fabrications and measurements technologies.
Impact of body position on hemodynamic measurements during exercise: A tale of two bikes
Authors: Kirupaharan Pradhab , Lane James , Melillo Celia , Paul Deborah , Amoushref Alla , Abdi Sami Al , Tonelli Adriano R.
Published: January 2024

The addition of exercise testing during right heart catheterization (RHC) is often required to accurately diagnose causes of exercise intolerance like early pulmonary vascular disease, occult left heart disease, and preload insufficiency. We tested the influence of body position (supine vs. seated) on hemodynamic classification both at rest and during exercise. We enrolled patients with exercise intolerance due to dyspnea who were referred for exercise RHC at the Cleveland Clinic. Patients were randomized (1:1) to exercise in seated or supine position to a goal of 60 W followed by maximal exercise in the alternate position. We analyzed 17 patients aged 60.3 ± 10.9 years, including 13 females. At rest in the sitting position, patients had significantly lower right atrial pressure (RAP), mean pulmonary artery pressure (mPAP), pulmonary artery wedge pressure (PAWP) and cardiac index (CI). In every stage of exercise (20, 40, and 60 W), the RAP, mPAP, and PAWP were lower in the sitting position. Exercise in the sitting position allowed the identification of preload insufficiency in nine patients. Exercise in either position increased the identification of postcapillary pulmonary hypertension (PH). Body position significantly influences hemodynamics at rest and with exercise; however, mPAP/CO and PAWP/CO were not positionally affected. Hemodynamic measurements in the seated position allowed the detection of preload insufficiency, a condition that was predominantly identified as no PH during supine exercise.
Green synthesis of Dextrin‐graft‐poly(allyl amine‐co‐methacrylic acid)/reduced graphene oxide composite and its application for dye and pesticide removal from the aqueous medium
Authors: Ray Jagabandhu , Sasmal Dinabandhu , Jana Subinoy , Tripathy Tridib
Published: January 2024

A Dextrin‐graft‐poly(allyl amine‐co‐methacrylic acid)/reduced graphene oxide (DEXTGP/RGO) is synthesized through the grafting of a combination of allyl amine (AAM) and methacrylic acid (MAA) monomers onto the dextrin polysaccharide backbone by using the free radical copolymerization technique in an aqueous medium, with potassium peroxydisulfate serving as the initiator followed by the partial reduction of graphene oxide (GO). Various characterization techniques including FTIR, 1H/13C NMR, XRD, FESEM, EDAX, and BET analysis are utilized to characterize both the synthesized DEXTGP/RGO composite and graft copolymer. Investigations are conducted on multiple operational variables, including adsorption kinetics, isotherms, and thermodynamic parameters, for the adsorption of both MB and PL. Both intra‐particle diffusion kinetic model and pseudo‐second‐order kinetics are observed to follow for the adsorption of MB, while the Langmuir isotherm model provided a good fit for the equilibrium data. In contrast, the adsorption of PL displayed solely pseudo‐second‐order kinetics, while the equilibrium data shows good agreement with both the Langmuir and Dubinin‐Radushkevich isotherm models. Maximum adsorption capacity (
) of the RGO composite is found to be 932.56 mg/g for MB and 311.63 mg/g for PL. The thermodynamic analysis revealed that the adsorption of dye and pesticide onto the RGO composite is a spontaneous process.
Recent Advances on the Development of Early Transition Metal Complexes for Photo‐Assisted Cytotoxicity Applications
Authors: Wahengbam Sharmila , Musib Dulal , Roy Mithun
Published: January 2024

For targeted therapy, the strategic use of an inactive precursor or “prodrug” could be an attractive strategy. Photo‐assisted chemotherapy offers a smart opportunity for developing new inorganic prodrugs for selective and temporal regulation on the chemotherapeutic activity of the prodrugs with light. The 3d transition metal complexes with versatile coordination number and geometry, redox, thermodynamic and kinetic properties, the presence of low‐energy metal‐centered electronic transitions, and the ability to exhibit light‐assisted chemical reactions have emerged as strategic tools for photo‐chemotherapeutic applications. Transition metal complexes are typically characterized by metal‐centered, ligand to metal, metal to ligand or intra‐ligand electronic transitions, and photo‐activated electronic states of the transition metal complexes potentially exhibit a wide range of chemical reactions viz. intramolecular oxido‐reduction reactions, intramolecular rearrangements, ligand exchange reactions or energy transfer those cascades into the generation of ROS (⋅OH, O2−⋅, O22−, 1O2), small molecules like H2, N2, CO or NO, and alkyl or aryl radicals. Applications of photo‐activable transition metal complexes for generating cytotoxic ions or radicals in the presence of light have emerged as an attractive strategy for photo‐activated chemotherapy (PACT). Here in, we reviewed the photophysical and photochemical aspects of the early transition metal complexes exhibiting photo‐ activated chemotherapy.
An Experimental and Computational Approach to The Microwave‐Assisted Synthesis of 2’‐Hydoxychalcone Derivatives in 1‐Dodecyl‐3‐Methylimidazolium Bromide ([DDMIm]Br) Ionic Liquids
Authors: Wahyuningrum Deana , Nur Pasya Nadya , Eduardus Eduardus , Handayani Nurrahmi , Damayanti Sophi
Published: January 2024

Four derivatives of 2’‐hydoxychalcone were synthesized through Claisen‐Schmidt condensation by combining 2’‐hydroxyacetophenone and four different benzaldehyde derivatives (o‐vanillin, salicylaldehyde, p‐anisaldehyde, and benzaldehyde) in the presence of a base. The reactions took place in an ionic liquid, 1‐dodecyl‐3‐methylimidazolium bromide ([DDMIm]Br), and were facilitated by microwave irradiation. The reactions were completed within 10 to 15 minutes, yielding products with chemical yields ranging from 52.64 % to 83.42 %. The structures of the synthesized products were confirmed using 1H NMR and 13C NMR spectroscopy. Additionally, antimicrobial activity tests demonstrated the effectiveness of specific derivatives against Staphylococcus aureus and Escherichia coli, underscoring the importance of hydroxy and methoxy groups on the aromatic ring in inhibiting microbial growth. These findings provide valuable knowledge for developing chalcone derivatives with improved properties and potential applications in drug discovery. Furthermore, the synthesized products′ reactivity was analyzed using Frontier Molecular Orbital (FMO) and their reactivity site was mapped using Molecular Electrostatic Potential (MEP). Lastly, molecular docking analysis was attempted to explain antibacterial activities from all products. Nonetheless, the molecular docking simulations conducted in this study were inadequate to fully account for the antimicrobial activity observed in all the products.
Design of New Second‐Generation TRK Inhibitors Targeting Tropomyosin Receptor Kinases by Using Molecular Docking, Molecular Dynamics Simulations and ADMET Properties
Authors: Zhao Kaihui , Cui Yang , Tang Wenhao , Shi Kang , Pan Haiyu , Zhong Qidi
Published: January 2024

TRK, as a type of cell surface protein, plays a critical role in various biological processes, particularly as a key target for cancer treatment. We explored the correlation between the structure and activity of indole‐2‐one derivatives through investigations involving 3D‐QSAR molecular modelling, molecular docking, molecular dynamics, and ADMET property research. The statistical data from the CoMFA and CoMSIA models exhibit excellent internal stability (CoMFA: q2=0.622, r2=0.992; CoMSIA: q2=0.740, r2=0.972). Further molecular docking unveiled the interaction mechanism between small molecules and receptor proteins, demonstrating that the hydrogen bonding between amino acids Met590 and Glu592 and small molecules could enhance the ligand‐receptor binding affinity. Based on the 3D‐QSAR model and molecular docking, we designed and predicted the activity of eight new molecules, which displayed high expected activity. Subsequently, through 100 ns MD simulations and binding free energy calculations, we affirmed the stability of the molecular docking results. Finally, we employed ADMET to predict the pharmacokinetic properties of the newly designed molecules, validating their commendable drug‐like characteristics. These research findings provide valuable references for the design and development of novel TRK inhibitors, offering fresh perspectives for subsequent drug design.
Superparamagnetic Nanoparticles with Phosphorescent Complexes as Hybrid Contrast Agents: Integration of MRI and PLIM
Authors: Rivas Aiello Maria Belen , Kirse Thomas M. , Lavorato Gabriel C. , Maus Bastian , Maisuls Iván , Kuberasivakumaran Shivadharshini , Ostendorp Stefan , Hepp Alexander , Holtkamp Michael , Winkler Elin L. , Karst Uwe , Wilde Gerhard , Faber Cornelius , Vericat Carolina , Strassert Cristian A.
Published: January 2024

Two different hybrid nanosystems are prepared by loading highly crystalline, monodisperse magnetite nanocubes (MNCs) with phosphorescent Pt(II) complexes (PtCxs). One involves the encapsulation of the hydrophobic PtCx1 within an amphiphilic comb polymer (MNC@poly(maleic anhydride‐alt‐1‐octadecene) [PMAO]–PtCx1), whereas the other involves the direct binding of the hydrophilic PtCx2 to the surface of the MNC mediated by a ligand‐exchange procedure (MNC@OH–PtCx2). Both systems are evaluated as potential candidates for multimodal imaging in magnetic resonance imaging (MRI) and photoluminescence lifetime imaging micro(spectro)scopy (PLIM). PLIM measurements on agarose phantoms demonstrate significantly longer excited‐state lifetimes compared to the short‐lived autofluorescence of biological background. Additionally, both nanosystems perform as effective MRI contrast agents (CAs): the r2* values are 3–4 times higher than for the commercial CA ferucarbotran. MNC@PMAO–PtCx1 particles also cause significant increases in r2. While the ligand exchange procedure efficiently anchors PtCxs to the MNC surface, the polymeric encapsulation ensures higher colloidal stability, contributing to differences in PLIM and MRI outcomes. In these results, the successful integration of two complementary noninvasive imaging modalities within a single nanosystem is confirmed, serving as the impetus for further investigation of such systems as advanced multimodal–multiscale imaging agents with dual orthogonal readouts.
Top‐down Surfactant‐Free Synthesis of Supported Palladium‐Nanostructured Catalysts
Authors: Schott Christian M. , Schneider Peter M. , Sadraoui Kais , Song Kun‐Ting , Garlyyev Batyr , Watzele Sebastian A. , Michalička Jan , Macak Jan M. , Viola Arnaud , Maillard Frédéric , Senyshyn Anatoliy , Fischer Johannes A. , Bandarenka Aliaksandr S. , Gubanova Elena L.
Published: January 2024

Nanostructured palladium (Pd) is a universal catalyst that is widely used in applications ranging from catalytic converters of combustion engine cars to hydrogenation catalysts in industrial processes. Standard protocols for synthesizing such nanoparticles (NPs) typically use bottom‐up approaches. They utilize special and often expensive physical techniques or wet‐chemical methods requiring organic surfactants. These surfactants should often be removed before catalytic applications. In this article, the synthesis of Pd NPs immobilized on carbon support by electrochemical erosion without using any surfactants or toxic materials is reported. The Pd NPs synthesis essentially relies on a Pd bulk pretreatment, which causes material embrittlement and allows the erosion process to evolve more efficiently, producing homogeneously distributed NPs on the support. Moreover, the synthesized catalyst is tested for hydrogen evolution reaction. The activity evaluations identify optimal synthesis parameters related to the erosion procedure. The electrocatalytic properties of the Pd NPs produced with sizes down to 6.4 ± 2.9 nm are compared with a commercially available Pd/C catalyst. The synthesized catalyst outperforms the commercial catalyst within all properties, like specific surface area, geometric activity, mass activity, specific activity, and durability.
Autonomous vehicle security: Current survey and future research challenges
Authors: Pali Isha , Amin Ruhul , Abdussami Mohammad
Published: January 2024

The advancement in technology and the adoption of innovative developments have made our lives easier. Every industry, from agriculture to transport, has experienced this advancement. The entire transportation system is in the process of becoming intelligent. Smart mobility of autonomous vehicles is an important part of the upcoming smart cities. The autonomous vehicle provides functionalities for safety and convenience. It has been an emerging field with a lot of attention and still under advancement and requires a thorough study and solutions for potential challenges and opportunities. Despite impressive advantages, it has some security vulnerabilities which could lead to life‐threatening consequences. Though they could prevent road accidents by eliminating human errors from the driving process, they also create the possibility of cyber‐physical attacks on the vehicular controlling system. For this, many researchers have focused on the security attacks and defenses in autonomous vehicular systems. A 360‐degree research has been undertaken to understand the concept of autonomous vehicles entirely, such as history, social impacts, difficulties and challenges, current product developments, and security aspects. Also, a vehicular architecture is proposed by integrating various technologies such as 5G, SDN, cloud, and so forth, its possible security attacks are mentioned.
Influence of modeling choices and prior information on the Bayesian assessment of a reinforced concrete bridge
Authors: Vereecken Eline , Botte Wouter , Lombaert Geert , Caspeele Robby
Published: January 2024

A lot of bridges are aging and reaching the anticipated service life. To gain insight in their remaining resistance, inspections and measurements can be performed. The resulting information and data can be used to update variables in the degradation models of these bridges. To account for spatial variation, degradation variables can be modeled with random fields. The random fields of the degradation variables are updated based on a Bayesian inference procedure, where different types of heterogenous and indirect data are accounted for. Nevertheless, in this procedure, various assumptions need to be made, such as the quantification of measurement uncertainty, the structural and degradation model to be used, the prior distributions of the variables of interest, and so forth. These assumptions can influence the results of the Bayesian inference. Hence, in this work, it will be investigated what the influence is of different assumptions and how they affect the localization and quantification of damage. This will be done by application to a reinforced concrete girder bridge. The main conclusions are that the model used in the Bayesian inference procedure should resemble the actual structure as good as possible and that simplifications that are allowed in the design can lead to posterior distributions deviating a lot from the actual situation. Moreover, it is illustrated how information from visual observations can be included in the definition of the prior distributions and how this has a beneficial effect on the posterior predictions.
Diversifying “English” at the Decolonial Turn
Authors: Canagarajah Suresh
Published: January 2024

In this brief forum article, I draw from the disciplinary orientation of linguistic anthropology to discuss how a collection of linguistic and semiotic resources gets enregistered as the “language” for specific communicative activities. Enregisterment is an ongoing social and ideological process whereby a semiotic corpus gets identified as conventional for an activity or identity (see Agha, 2005). At a larger scale of consideration, it can also help explain what is identified as “English” in any given time and place. It is more appropriate to focus on communicative activity as the unit of analysis for the diverse semiotic resources constituting it, rather than assuming a labeled language as the starting point for our teaching or research. In place of relying on formal proficiency in English grammar, which might have variable relevance in communicative practices, we must prepare students for the diverse semiotic repertoires needed for their purposes and develop in them the dispositions to always attune to the mix of entangled resources in any activity.
Post‐combustion capture and other Carbon Capture and Sequestration (CCS) technologies: A review
Authors: Ibigbami Olayinka Abidemi , Onilearo Oluwatimilehin Daniel , Akinyeye Richard Odunayo
Published: January 2024

Technologies for capturing and storing carbon dioxide (CO2) and strategies for sequestering carbon dioxide have received a lot of interest in recent years as potential remedies for the curtailment of the growing concerns of emissions of greenhouse gases and global warming. This article provides a comprehensive analysis on the trends in research and development in the area of CO2 carbon capture and sequestration at the moment. The review explores various technological approaches for capturing CO2 from industrial emissions, such as post‐combustion capture systems, pre‐combustion capture systems, and oxy‐fuel combustion system. It also gives a major insight into the post‐combustion capture of carbon by means of a summary, information obtained via a personal interview with a Combustion Based Unit (CBU) plant manager. Additionally, different methods for storing and sequestering the aforementioned gas, including geological and oceanic archiving, and mineralization, are examined. By synthesizing the findings from a wide range of studies and research papers, this literature review provides valuable insights into the current technologies for CO2 capture, storage, and sequestration, contributing to the ongoing efforts in addressing climate change and achieving sustainable development goals.
Maternal supplementation with docosahexaenoic acid does not cause constriction of fetal ductus arteriosus: randomized controlled trial
Authors: Zielinsky P. , Alves D. R. , Foresti J. D. Á. , Guimarães D. B. , Zucatti K. P. , Vian I.
Published: January 2024

Objective

Docosahexaenoic acid (DHA) is recommended routinely in pregnancy to promote fetal development. DHA has anti‐inflammatory activity, but its effects on the fetal heart and circulation are unknown. This study aimed to investigate whether maternal DHA supplementation in the third trimester affects maternal prostaglandin levels and fetal ductus arteriosus flow dynamics.

Methods

This was a double‐blind randomized controlled trial with parallel groups conducted between 2018 and 2021. Pregnant women aged over 18 years with a normal fetus at 27–28 weeks' gestation showing no cardiac/extracardiac anomalies or ductal constriction were eligible for the trial. Women consuming substances with a known inhibitory effect on prostaglandin metabolism, such as non‐steroidal anti‐inflammatory drugs and polyphenol‐rich foods, were excluded. The intervention group received oral supplementation of omega‐3 with 450 mg/day of DHA for 8 weeks and the placebo group received capsules of soy lecithin for 8 weeks. Anthropometric measurements, assessment of polyphenol and omega‐3 consumption, fetal morphological ultrasound examination, fetal Doppler echocardiographic examination and blood sample collection were performed at the start of the study and the latter two were repeated at follow‐up. Prostaglandin E2 (PGE2) level and echocardiographic parameters were compared between the intervention and placebo groups and between baseline and follow‐up.

Results

A total of 24 participants were included in each group. After 8 weeks, there were no significant differences between the intervention and placebo groups in maternal serum PGE2 level or Doppler echocardiographic parameters of ductal flow. No case of ductus arteriosus constriction was observed. The expected intragroup changes in cardiac morphology, as a result of advancing gestation, were present.

Conclusions

Maternal DHA supplementation in the third trimester at a clinically recommended dose did not result in inhibition of PGE2 or constriction of the ductus arteriosus. These findings should be confirmed in postmarket surveillance studies with larger patient numbers in order to test the full safety profile of DHA and provide robust clinical reassurance. © 2024 International Society of Ultrasound in Obstetrics and Gynecology.
Atypical magnetic resonance imaging findings of a vertebral melanotic melanoma in a dog
Authors: Prodger Alice , Rodriguez Tomas Elvira , Mallol Claudia , Costa Taiana , Benito Miguel
Published: January 2024

An 8‐year‐8‐month‐old whippet was investigated by magnetic resonance imaging for acute thoracolumbar discomfort and pelvic limb stiffness, which had progressed to severe ambulatory paraparesis and proprioceptive ataxia of the pelvic limbs in the 24 hours before presentation. An aggressive, extradural T10 vertebral mass‐like lesion was identified, with resultant marked compression of the spinal cord. The lesion was heterogeneously T2‐weighted hyperintense and moderately T1‐weighted hyperintense relative to the adjacent vertebrae and paravertebral musculature. Cytological analysis of the lesion was consistent with a melanotic melanoma, which was confirmed by histopathological analysis and immunohistochemistry. The vertebral column is an uncommon location for either primary or metastatic melanomas in both humans and veterinary species. This lesion was particularly unusual in that its imaging characteristics were not typical for melanotic melanoma. This case report illustrates the unusual anatomical and imaging features of this tumour and outlines the diagnostic considerations pertinent to this case.
Association between troponin I levels and mortality among patients undergoing acute high‐risk abdominal surgery—A cohort study
Authors: Kanstrup Charlotte Tiffanie Bendtz , Serup Camilla Mattesen , Svarre Kristina Johansen , Rasmussen Maja Christine , Lundstrøm Lars Hyldborg , Kleif Jakob , Bertelsen Claus Anders
Published: January 2024

Background

Myocardial injury after noncardiac surgery (MINS) is associated with 30‐day mortality in heterogeneous surgical populations but is barely described after acute high‐risk abdominal surgery. The impact of dynamic changes has not previously been investigated. The objectives were to determine the incidence of MINS in this population, the association between mortality and MINS, and whether plasma troponin I (TnI) dynamics have any impact on mortality.

Methods

A prospective cohort study of 341 patients undergoing acute high‐risk gastrointestinal surgery was conducted. Plasma TnI was measured at the first four postoperative days. MINS was defined as any increased TnI level >59 ng/L. TnI dynamic required either two succeeding measurements of TnI >59 ng/L with a >20% increase/fall or one measurement of TnI >59 ng/L with a succeeding measurement of TnI <59 ng/L with a >50% decrease. Adjusted mortality rates were calculated using inverse probability of treatment weighting and competing risk analyses.

Results

The incidence of MINS was 23.8% and dynamic TnI changes occurred in 15.6% of the patients. The unadjusted 30‐day and 1‐year mortality were 19.8% and 35.9% in patients with MINS, compared with 2.7% and 11.6%, respectively, in patients without MINS (p < 0.001). After adjusting, the differences remained significant. There was no difference in mortality between patients with or without dynamic changes in TnI level.

Conclusion

MINS occurred frequently and was associated with increased mortality. TnI monitoring might help identify patients with increased risk of mortality and improve care. Research on preventive measures and treatments is warranted.

Trial Registration Number and Agency

ClinicalTrials.gov Identifier: NCT05933837, retrospective registered.
Behavior of polar bear (Ursus maritimus) cubs post‐den emergence at the Detroit Zoo
Authors: Gartland Kylen N. , Humbyrd Mary , Brightrall Tami , Meister Betsie , Fuller Grace
Published: January 2024

In the wild, female polar bears (Ursus maritimus) with cubs may spend extended periods of time within the den following initial emergence. As a result, studying behavioral development of cubs at the denning site has been difficult and unreliable. Although care staff at zoological institutions have easier access to animals, every effort is made to minimize intrusions to maternal groups, which presents research limitations. Detroit Zoological Society staff used audio‐equipped cameras installed in behind‐the‐scenes spaces to conduct approximately 9 weeks of monitoring on two female polar bear cubs of the same litter, one of whom (Laerke) was hand‐reared while the other (Astra) was mother‐reared. Monitoring spanned ages 14–24 weeks and consisted of 12, 5‐min focal observations per observation day timed to evenly cover the entire 24‐h day. Using generalized linear mixed models, we examined relationships between behavior and time of day, hour, and age. We also conducted descriptive analyses and used these to draw comparisons between the two cubs where appropriate. Despite different rearing environments, both cubs had highly comparable patterns of inactive, locomotory, and independent play behaviors. Astra generally decreased time spent nursing and in proximity to Suka as she aged. Data presented here represent a continuation of previous neonatal observations conducted on Astra, adding to the minimal body of knowledge currently available on first year polar bear cub development. We also report successful mitigation of stereotypic behavior in Laerke. Further studies of captive maternal groups can provide insight into this critical developmental stage, supporting both captive‐based breeding efforts and in situ conservation efforts.
Optimization of Energy Management Control Strategy for Hydrogen-Electric Hybrid Train
Authors: Sun Shijie , Gao Yang , Wang Jian , Shi Lei , Chen Limei , Xiang Weiran , Li Wenrong
Published: January 2024

In order to enhance the stability of the energy regulation of the hydrogen-electric hybrid train and reduce the impact on the train bus of the hybrid system during the energy regulation process, an improved rule-based instantaneous power control strategy is proposed, in which the bus voltage is introduced into the control link to enhance the system stability. The simulation results prove that the optimized control strategy improves the stability of the high-voltage DC link of the hybrid system, avoids the high-voltage surging to the super-capacitor system and the traction system, and extends the service life of the super-capacitor at the same time.
Safety Technologies and Challenges of Hydrogen-Powered Rail Transport
Authors: Wang Jian , Gao Yang , Sun Shijie , Shi Lei
Published: January 2024

As one of the many energy alternatives, the interest in hydrogen-powered rail transport is gradually increasing worldwide, and some railway vehicles powered by hydrogen are currently in operation or undergoing experimental projects. However, due to the unsafe and unstable nature of hydrogen energy, hydrogen has potential leakage and explosion hazards in all rail transport applications. This paper summarizes the main application technologies of hydrogen safety in light of the research progress and unsafe factors in the process in the field of hydrogen-powered rail transport in various countries, at the same time clarifies the development challenges and difficulties of hydrogen-powered rail transport in the future, and makes suggestions for the development of hydrogen-powered rail transport safety in China.
Design Method of the Hydrogen Liquefaction Process with Catalyst-Filled Heat Exchanger Model
Authors: Lv Cui , Zhou Gang , Wang Jinzhen , He Ming , Wu Jihao , Gong Linghui
Published: January 2024

Hydrogen liquefaction is a crucial process in the liquid hydrogen industry, and the use of liquid hydrogen is becoming increasingly important for storing and transporting hydrogen over long distances. Hydrogen has two spin isomers, that is ortho and para hydrogen. One of the challenges in this process is the conversion of ortho to para hydrogen in the heat exchanger. As the conversion process releases heat and is a spontaneous behavior, it is important to ensure that the content of para hydrogen in the final product is at least 95%. Unfortunately, there are currently no known commercial models that contain catalyst-filled heat exchangers for converting ortho hydrogen to para hydrogen. In this paper, Aspen Hysys is used to construct a new design method for hydrogen liquefier with O-P hydrogen conversion heat exchanger. Using this model, one 5 ton per day hydrogen liquefier is designed, and the key parameters of the process are obtained, which will provide a new method for the design of hydrogen liquefaction process in the future.
Hydrogen Leakage Detection in Confined Spaces with Drift Suppression Based on Subspace Alignment
Authors: Se Haifeng , Jiang Jinhai , Sun Chuanyu , Song Kai
Published: January 2024

Gas sensor has been widely used in flammable gas detection. In order to solve the problem that gas sensors are susceptible to drift in hydrogen leakage detection in confined spaces, a drift compensation framework based on subspace alignment is proposed. First, global domains and subdomains are aligned simultaneously in the new subspace, thus reducing the distribution difference between the source domain and the target domain. Then, the proposed method utilizes extreme learning machine (ELM) to iteratively refine the prediction results of the target domain, and continuously optimizes the subspace and classifier. In this way, the proposed method realizes drift compensation at the feature level. Compared with the existing methods, the proposed method achieves the highest accuracy of 79.83% in the long-term drift scenario. Therefore, the experimental results show that the proposed method is competent for hydrogen leakage detection with drift, and can provide a reference for the design of drift compensation method based on gas sensors.
Design of 10 L/s Liquid Hydrogen Pump with Integrated Inducer and Centrifugal Impeller
Authors: Li ZiWei , Lv Cui , Wu Jihao , Gong Linghui , Wang Jinzhen , Shang Jin , He Ming
Published: January 2024

With the global focus on energy and environmental issues, hydrogen energy development has become more and more important. The liquid hydrogen pump is an important equipment for hydrogen transportation, whose performance is significantly decided by the impeller. In this paper, we designed an integrated impeller with an inducer and an centrifugal impeller and optimized the axial length and outlet angle of the centrifugal impeller. Grid independence and cross validation prove that the simulation model and results are reliable. It is worth noting that a high roughness is given to the impeller surfaces in our simulation to obtain results closer to the real situation. By analyzing the pressure and relative liquid flow angle distribution in the fluid domain, the structural design of the impeller is optimized, and then the performance curve is obtained. The simulation results will provide a guidance for the manufacture of our liquid hydrogen pump, and also provide a reference for the design and manufacture of other liquid hydrogen pumps.
Experimental Research on High-Pressure Hydrogen Leakage and Diffusion of Hydrogen Refueling Station
Authors: Jiang Bin , Zhen Tongshen , Fang Fangfang
Published: January 2024

As the infrastructure to provide hydrogen for hydrogen fuel cell vehicles, hydrogen refueling station is a very important part of hydrogen energy utilization. However, due to the characteristics of hydrogen, such as flammability and explosion, low density, wide range of explosive limit concentration, hydrogen refueling station accidents often occur. The existing research on hydrogen refueling stations often uses the method of numerical simulation, and mainly considers the leakage of hydrogen storage tank. There are few relevant experimental studies and little consideration is given to the case of hydrogen pipeline leakage. In order to explore the phenomenon and rule of high-pressure hydrogen leakage and diffusion in the pipeline of hydrogen refueling stations, a full-size high-pressure hydrogen leakage test facility is built based on a real hydrogen refueling station. The vehicle-mounted high-pressure hydrogen storage tank is used as the high-pressure hydrogen gas source to provide constant hydrogen pressure to the test section through the combination of different valves in the pipeline and the instrument control system. By changing different leakage sizes and pressures, the concentration distribution and influence factors after hydrogen leakage are analyzed, which provides an important basis for the optimal layout and operation and maintenance of the safety facilities of the existing hydrogen refueling station.
Deep Neural Network for Prediction of Adsorbent Selectivity on Hydrogen Purification
Authors: Li Chenglong , Xie Chengsi , Zong Yi , Chahine Richard , Yang Tianqi , Ye Feng , Xiao Jinsheng
Published: January 2024

With emergence of new materials, more and more materials are available for adsorption and separation processes. The adsorption selectivity of adsorbent to adsorbate is one of the important indicators in choosing materials. Because the adsorption experiment of the mixture is time-consuming and difficult, the selectivity of the adsorbent is generally calculated by the ideal adsorbed solution theory (IAST). Taking the CO2/H2 gas mixture as an example, this paper proposes a new adsorption selectivity calculation method based on a deep neural network (DNN) with 5 hidden layers, which takes the molar fraction of CO2, adsorption pressure and Langmuir adsorption isotherm parameters as the inputs of DNN. Combining the DNN and the NIST/ARPA-E database to quickly and accurately calculate the adsorption selectivity, the hydrogen purification and carbon dioxide storage materials can be quickly screened.
Scheduling of Renewable Energy Hydrogen Production System Based on Two—Stage Distribution Robust Optimization
Authors: Xia Luohui , Wu Bin , Zhou Linwei , Liang Tao , Liu Zicong
Published: January 2024

Hydrogen energy has various advantages such as cleanliness, storage and high energy carrier, which is considered to be one of the key paths to achieve the goal of “double carbon”. Utilization of hydrogen production in renewable energy is an important technical means to achieve new energy amazing and energy cleaning utilization. In response to the uncertainty characteristics of local scenery resources and local electricity load and hydrogen load demand, considering the investment cost of hydrogen storage system and the influence of flexible load of electric load on the optimal operation of the system, a two-stage distributed robust optimization model for hydrogen production system (H2-RES) from renewable energy is established, the capacity of the first stage hydrogen production system is determined by the system economy, and the second stage is designed to optimize the real-time scheduling of the system, aiming at the total operating cost, which is solved by C&CG algorithm, finally, an example is given to verify the validity of the proposed model.
Multivariate Based Alkaline Electrolyzer Digital Twin Model Construction
Authors: Liang Tao , Liu Zicong , Sun Hexu , Tan Jianxin
Published: January 2024

Electrolytic water hydrogen production systems are highly coupled and operate under complex and dangerous conditions, making it difficult to carry out extreme experiments on physical objects. In this paper, the alkaline electrolyzer is studied and mathematical and three-dimensional models are developed for it. The System operation data shows that temperature, pressure and alkaline flow rate all have effects on the hydrogen concentration in oxygen and voltage. Among them, hydrogen concentration in oxygen is one of the important factors affecting the safety of the system, and changing both pressure and alkali flow rate respectively will cause significant changes in hydrogen concentration. Based on the system operation data, a multivariate nonlinear fitting of the empirical equation using Matlab was performed to establish the voltage model, Faraday efficiency model, hydrogen concentration in oxygen model and system pressure model of the alkaline electrolyzer. And the model simulation results were analyzed and verified theoretically, which were consistent with the actual engineering. The mathematical model of the alkaline electrolyzer is combined with the 3D model, and the digital twin model of the alkaline electrolyzer is controlled in real time by PLC. The mapping of the alkaline electrolyzer in the virtual space is realized, which provides an experimental platform for the subsequent study of wide power fluctuation.
Thermal Analysis and Optimization of Cold-Start Process of Alkaline Water Electrolysis System
Authors: Deng Xintao , Yang Fuyuan , Li Yangyang , Dang Jian , Ouyang Minggao
Published: January 2024

In this paper, a thermal model of commercial alkaline water electrolysis system is presented, including energy and mass balance model between system components and a two-stage graybox model of alkaline electrolyzer. The aim of this work is to study and improve the thermal behavior during cold-start process of electrolysis system. The model is used to simulate the cold-start process under various parametric settings such as electrolyte flow rate and electrolyte volume. Then, several optimization schemes are proposed and evaluated to be promising.
Effect of Flow Channel Blockage on the Scale-Up of Proton Exchange Membrane Fuel Cells
Authors: Wang Bin , Pan Weitong , Tang Longfei , Zhang Guoyu , Gao Yunfei , Chen Xueli , Wang Fuchen
Published: January 2024

Optimizing flow field structure can effectively improve the performance of Proton Exchange Membrane Fuel Cell (PEMFC). Adding the block in the flow channel is one of the approaches. In this work, the enhanced transport characteristic of the block is re-examined, and its effect on the performance of the fuel cell scale-up is further revealed. The models of single-channel fuel cells with different lengths L and blockage ratio β are developed. Results show that the best cell performance exhibits when β = 100% due to the combined effect of the block and upstream zone. The convection appears below the block, and higher upstream pressure is induced, both of which increase the oxygen concentration at the catalyst layer. Besides, results indicate that the performance of the scaled-up fuel cell with blockage increases at a slower rate. Combined with the pump power, it is found that the addition of the block with β = 100% is indeed beneficial for the fuel cell scale-up. The findings of different blockage effects on different-sized cells provide guidelines for the flow field design.
Strategic Analysis of Hydrogen Energy Policies and Technology Layout in Major Countries
Authors: Han Xiao , Yan Hua-guang , Kang Jian-dong , Li Yang
Published: January 2024

In the context of the global clean and low-carbon energy transition, hydrogen energy has become an important direction for energy technology innovation in the contemporary world. Many countries around the world have paid great attention to the development of hydrogen energy and leveraged it to the national strategies. This study firstly reviews the development of global hydrogen energy, focusing on the global hydrogen energy supply, hydrogen energy demand, the current situation and development trend of hydrogen energy. Secondly, based on data collected from government websites, key R&D institutions and well-known databases (e.g. CODIS database), a strategic analysis of hydrogen energy policies and technologies of main countries is conducted. In terms of policy, textual analysis is used to analyse the global hydrogen energy layout direction and the strategic positioning, strategic layout and strategic objectives of hydrogen energy in countries such as the United States, European Union, Japan and China. In terms of technology, the keyword search method is used to obtain data on scientific research projects in the field of hydrogen energy, and quantitative analysis is conducted to analyse the characteristics of the technical layout of global hydrogen energy research projects, and to analyse the funding of hydrogen energy projects and the focus of hydrogen energy technology research. Finally, suggestions for the future development of hydrogen energy are discussed.
Internal structure of hairy rotating black holes in three dimensions
Authors: Gao Ling-Long , Liu Yan , Lyu Hong-Da
Published: January 2024

Abstract

We construct hairy rotating black hole solutions in three dimensional Einstein gravity coupled to a complex scalar field. When we turn on a real and uniform source on the dual CFT, the black hole is stationary with two Killing vectors and we show that there is no inner horizon for the black hole and the system evolves smoothly into a Kasner universe. When we turn on a complex and periodic driving source on the dual CFT with a phase velocity equal to the angular velocity of the black hole, we have a time-dependent black hole with only one Killing vector. We show that inside the black hole, after a rapid collapse of the Einstein-Rosen bridge, oscillations of the scalar field follow. Then the system evolves into the Kasner epoch with possible Kasner inversion, which occurs in most of the parameter regimes. In both cases, one of the metric fields obeys a simple relation between its value at the horizon and in the Kasner epoch.
The effect of surface finish and post-processing on mechanical properties of 17-4 PH stainless steel produced by the atomic diffusion additive manufacturing process (ADAM)
Authors: Opoz Tahsin Tecelli , Burgess Andrew , Ahuir-Torres Juan Ignacio , Kotadia Hiren Ramniklal , Tammas-Williams Samuel
Published: January 2024

This study investigates the influence of surface finish and post-processing conditions on the mechanical properties of 17-4 PH stainless steel (SS) produced using the atomic diffusion additive manufacturing process (ADAM). Diverse sample orientations, including horizontal (0°), 30°, 60°, and vertical (90°), were examined, with selected samples undergoing post-processing through machining, polishing, and heat treatment. Tensile strength testing, surface roughness measurement, and hardness measurement were conducted to assess the effect of surface finish conditions and post-processing on mechanical properties. The results reveal significant variations in the tensile strength of the samples based on the build orientation (183.5 to 1034.5 MPa), and subsequent machining. Notably, post-built machining is found to enhance both the absolute ultimate tensile strength (UTS) and the isotropy of the material. Further improvements are attainable through heat treatment. A microstructure analysis, in conjunction with tensile testing outcomes, demonstrates the potential for refining the properties of ADAM-printed samples through suitable machining, heat treatment, and geometry modifications. This study identifies avenues for ongoing process development and outlines possibilities for enhancing mechanical properties of additive manufactured parts, particularly through ADAM process.
The triangulation complexity of elliptic and sol 3-manifolds
Authors: Lackenby Marc , Purcell Jessica S.
Published: January 2024

The triangulation complexity of a compact 3-manifold M is the minimal number of tetrahedra in any triangulation of M. We compute the triangulation complexity of all elliptic 3-manifolds and all sol 3-manifolds, to within a universally bounded multiplicative error.
Expression of glucose (GLUT) and glycerol (GLP) transporters in symbiotic and bleached Cassiopea xamachana (Bigelow, 1892) jellyfish
Authors: Carabantes Natalia , Grosso-Becerra María Victoria , Thomé Patricia E.
Published: January 2024

Cassiopea xamachana is a tropical medusa that lives in symbiosis with dinoflagellate algae, serving as a model organism for symbiotic studies. The symbiosis is necessary for this medusa to complete its life cycle. The symbiotic partners maintain a metabolic exchange of organic molecules that constitute an important source of energy for the animal host, with free organic molecules, like glucose and glycerol, being the primary source. This molecular exchange can be facilitated by cellular internal membrane transport proteins, such as Glucose membrane transporters (GLUTs) and Glycerol transport-like aquaglyceroporins (GLP-like), probably located at the symbiosomal interface. The present study was conducted in October 2021, evaluating the expression of transporter coding genes GLUT3, GLUT8, and GLP9 (two genes) by qPCR under conditions of symbiosis and after the loss of symbionts. Symbiotic medusae donated from Xcaret Park, Mexico (20° 34′ 24.59″ N; -87° 07′ 5.40″ W) were sampled and compared to medusae with an experimental decrease of algal symbionts. In agreement with glucose being an important mobile molecule, our results showed higher transcription levels for glucose transporters GLUT3 and GLUT8 in control compared to bleached medusae. By contrast, bleached medusae showed a higher expression of aquaglyceroporin transporters GLP9-1 and GLP9-2, probably associated with glycerol production after lipid catabolism, to compensate for lower organic carbon levels due to the loss of symbionts. Our results highlight the importance of free carbon molecules transported from symbiont to host and agree with glucose being an energy fuel for this symbiotic association.