bluuebunny/crossref_metadata_2025 huggingface dataset:
Unlocking a reductive hydroalkoxylation cascade for the stereoselective synthesis of cyclic ethers: total synthesis of (±)-isolaurepan and (±)-cis-lauthisan
Authors: Gharpure Santosh J. , Patel Raj Kumar
Published: September 2024

A Lewis acid-mediated, 5/6/7/8-endo-dig reductive hydroalkoxylation cascade on enynols gives expeditious, diastereoselective access to small and medium ring cyclic ethers with a long aliphatic side chain.
Photoinduced fluoroalkylation-peroxidation of alkenes enabled by ligand-to-iron charge transfer mediated decarboxylation
Authors: Huang Qiuwei , Lou Chenhao , Lv Leiyang , Li Zhiping
Published: September 2024

A photoinduced iron-catalyzed fluoroalkylation-peroxidation of activated and/or unactivated alkenes with fluoroalkyl carboxylic acids and hydroperoxide has been realized.
Hollow titanium nitride nanoshells for enhanced plasmon-driven hot electron generation and improved photocatalytic and photovoltaic applications
Authors: Moustafa Samar , Zayed Mohamed K. , Daffallah K. O. , Shaalan Nagih M. , Rashad Mohamed , Fares Hesham
Published: September 2024

We investigated spherical TiN nanoshells with a dielectric core. Geometrical optimized hollow TiN nanoshells exhibit the highest solar energy absorption among all TiN nanoshells and TiN and noble metal nanospheres for enhanced energy harvesting.
A microfluidic system for the cultivation of cyanobacteria with precise light intensity and CO2 control: enabling growth data acquisition at single-cell resolution
Authors: Witting Lennart , Seiffarth Johannes , Stute Birgit , Schulze Tim , Hofer Jan Matthis , Nöh Katharina , Eisenhut Marion , Weber Andreas P. M. , von Lieres Eric , Kohlheyer Dietrich
Published: September 2024

A versatile microfluidic platform with precise multi-parameter control for high-throughput cyanobacterial growth analysis at single-cell resolution.
Microfluidic antisolvent crystallization for chiral symmetry breaking
Authors: Jang Jiye , Coquerel Gerard , Seo Tae Seok , Kim Woo-Sik , Park Bum Jun
Published: September 2024

Microfluidic antisolvent crystallization was used to study the effect of solution volume on chiral symmetry breaking (CSB) in NaClO3 crystals. 100% CSB occurs below a critical emulsion volume due to rapid molecule depletion and suppressed nucleation.
High-selectivity turn-on fluorescence-based fluoride ion detection using histidine-functionalized UiO-66-NH2
Authors: Rizal B Muh , Mudasir  , Pambudi Fajar Inggit
Published: September 2024

The study elucidates UiO-66-NH2 functionalized with histidine for its capability in turn-on fluoride ion detection using various parameters such as synthesis condition, the effect of solvent media, pH, selectivity, and reusability.
Effect of temperature on the structure, catalyst and magnetic properties of un-doped zinc oxide nanoparticles: experimental and DFT calculation
Authors: Sharbatdaran Masoomeh , Janbazi Mehdi
Published: September 2024

Zinc oxide nanoparticles were synthesized using sol–gel and hydrothermal techniques and characterized at different calcination temperatures (400, 500, and 600 °C).
Structural insights and electronic state analysis of PtNi nanowire catalysts by operando high-energy resolution fluorescence detection X-ray absorption spectroscopy
Authors: Cao Weijie , Thakur Neha , Kumar Mukesh , Uchiyama Tomoki , Gao Yunfei , Tominaka Satoshi , Machida Akihiko , Watanabe Toshiki , Sato Ryota , Teranishi Toshiharu , Matsumoto Masashi , Imai Hideto , Sakurai Yoshiharu , Uchimoto Yoshiharu
Published: September 2024

Operando conventional and high-energy resolution fluorescence detection X-ray absorption spectroscopy were used to study the oxidation states and Pt–Pt bond length changes in PtNi nanowire catalysts under oxygen reduction reaction conditions.
Crystal structure, magnetotransport properties, and electronic band structure of V1−xTixSe2 single crystals
Authors: Sang Lina , Yuan Meng , Zhao Jinshi , Yang Guangsai , Yun Frank Fei , Li Zhi , Wang Xiaolin
Published: September 2024

The electrical properties of V1−xTixSe2 are highly tunable, suggesting a promising application in future electronic devices. This work reports the weak localization in VSe2 and TiSe2 single crystals, which can be modulated by the defect density.
High depolarization temperature and large piezoelectricity in BiScO3–PbTiO3–Bi(Zn1/2Ti1/2)O3 piezoelectric energy harvesting ceramics
Authors: Wang Huizhong , Yu Xiaole , Zheng Mupeng , Zhu Mankang , Hou Yudong
Published: September 2024

Achieving high values of both Td and HT-d33 in the BS–PT–BZT piezoelectric energy harvesting ceramics via the linear expansion of MPB and lattice tetragonality c/a modulation.
Biochar as sustained-release carbon source and carrier for microbial denitrification
Authors: Li Qiao , Liu Jie , Zhang Cunkuan , Wang Hui , Ding Wenchuan
Published: September 2024

The biochar used to improve the soil also affects the nitrogen cycle in the water after flowing into the waterbody. In this paper, the function of biochar prepared at different pyrolysis temperatures in the denitrification process in water is studied. Some substances on the surface of biochar can be used as a carbon source for microorganisms, but the carbon source provided by biochar is limited. With the increase of pyrolysis temperature, the effectiveness of biomass on the surface of biochar shows a downward trend. When the pyrolysis temperature is 300°C, the C element content on the surface of biochar is the highest, which is 1.76 mg·g−1, and the oxidizable part increases. Scanning electron microscopy (SEM) analysis confirmed that the surface of biochar was enriched with denitrifying bacteria and provided a usable carbon source.
Study on culture of stable aerobic granular sludge
Authors: Xu Yujie , Chen Shuo , Wu Chuanqi , Zhang Zhiming
Published: September 2024

In this study, three reactors were established with anaerobic plug-flow times of 1.5 hours, 1 hour, and 0.5 hours. The results indicated that the anaerobic plug-flow time of 1 hour constructed favorable "feast- famine" period ratio, promoting the enrichment of microorganisms that stored and utilized the internal carbon source, such as Phosphate and Glycogen Accumulating Organisms (PAO and GAO). This resulted in the formation of granular sludge with both short granulation time and structural stability. In contrast, shortening the anaerobic feed time to 0.5 hours was detrimental to the growth of GAO, leading to slow granularization of aerobic sludge. The anaerobic influent time of 1.5 h leads to the shortening of starvation period and poor stability of particle structure.
Influence of carbide tooth grinding parameters on shaping efficiency of high steel grade tubing
Authors: Tang Geng , Liu Qiang , Li Xue , Ding Liangliang , Zhang Lin , Yang Xing , Gong Hao
Published: September 2024

Complex oil and gas well service conditions very easily trigger downhole casing deformation and failure, resulting in most of the oil and gas field casing shaping and repairing the difficulty of rising, casing micro-plasticity and micro-expansion technology can effectively solve the problem of casing local shrinkage and bending and deformation, in order to study the grinding shoe alloy teeth cloth angle, grinding speed and grinding depth on the grinding force change rule, according to the grinding theory to establish a single tooth and casing microelement section plane numerical model Model, the use of Johnson-Cook damage isomorphism model to characterize the material dynamic cutting failure, through the numerical simulation results fitted to the grinding force as the dependent variable, alloy tooth angle, speed, depth of grinding for the independent variables of the evaluation formula. The analysis results show that the grinding force decreases with the change of alloy tooth front angle from 0° to 60°; the grinding force does not change significantly in the range of milling speed from 40r/min to 80r/min; and the grinding force increases gradually when the milling depth increases. It is concluded that the angle and depth of the alloy tooth front are the main controlling factors for controlling the grinding and milling capacity, and this understanding provides technical references for the design and optimization of casing repair and is of great significance for accurately predicting the shaping capacity of the deformed casing and ensuring the integrity of the wellbore.
Research on Vehicle Emission Factors in Wuhan Based on MOVES
Authors: Wang Xinyue , You Lianqing , Zheng Qi , Liang Jiaqi , Jiang Fayin , Yang Guiyong , Xie Gang
Published: September 2024

The emission factors of trucks are influenced by many factors, such as temperature, humidity, year, vehicle age and road type. In order to determine the emission factors of trucks under each influence, this paper analyzes MOVES in terms of scale, time, span, geographical boundary, vehicle type, road type, pollutant type and emission process, vehicle ownership, vehicle age distribution, fuel information, road type distribution, average speed distribution, mileage distribution, meteorological information and fuel information. The relative error between the results of this study and the emission factor of energy consumption method is compared, and the error between them is within 5%. The relevant results provide support for the calculation of pollutant emission inventory.
Resource-Dependent Sex Ratios in Lampreys: Implications for Ecological Stability and Economic Impact
Authors: Tan Ningxin
Published: September 2024

The sex ratio of the lamprey, a fish that is both bottom and active in the middle of the food chain, varies according to the state of environmental resources. Over the long term, due to its population explosion, the lamprey has taken a significant toll on economic fish stocks and has become a species considered a disaster by humans. This study aimed to assess the specific adaptive strategies of the lamprey and its impact on the ecosystem. In this paper, a detailed assessment of the impacts on the ecosystem and its stability was carried out by constructing an accurate model. The results of the study revealed key indicators such as economic losses, resource utilization, and impact factors of the lamprey on other organisms, thus effectively evaluating the resource utilization capacity of the lamprey within its habitat. This paper provides insight into the complexity of sex ratios to accommodate varying resource availability. By analyzing the pros and cons of such adaptations, thereby providing a comprehensive understanding of the subtle ecological interactions in the ecosystems inhabited by the lamprey.
Energy saving and safe operation of Tidal Pumping Stations
Authors: Zhao Fangling , Qiu Baoyun , Wang Huijie , Yan Tianxu
Published: September 2024

Tidal pumping station pumps would consume lots of energy for pumping massive water. This paper provides an effective method to optimize operating schedules of the tidal pumping stations. A multi-objective model was proposed to minimize the total switching times and energy power. In the model, sub-periods are divided according to heads. A classical tidal pumping station, which mainly serves for the China's South to North Water Transfer Project, is performed as a case. As the energy consumption per unit pumped decreases, the switching times increases, and the operational reliability of the T-PS decreases. The optimal operation scheme reduces the switching times by about 58.824% and saves the energy consumption per unit pumped by about 3.803%, respectively. Therefore, the optimal operation scheme not only has excellent safety but also effectively reduces the operation energy consumption. Thus, this paper could provide effective optimized operation schedules for tidal-pumping stations.
Optimization of frac imbibition process system in Lamadian oilfield
Authors: Jin Xiaoyi
Published: September 2024

The most effective way to develop oil fields is hydraulic fracturing. During the development process, it is found that the shut-in time after fracturing has a great impact on crude oil production, and the analysis believes that imbibition is the main reason. Therefore, it is necessary to study the influence of hydraulic fracturing on the imbibition law of oil reservoir, give full play to the imbibition function, and improve the development effect of oil field. In this paper, the relationship between imbibition and post- fracturing shut-in time and imbibition rate and post-fracturing shut-in time is studied, and on this basis, the production system is optimized and the limit shut-in time is determined.
Study on delamination exploitation limit of high water cut injection well in late period
Authors: Zhou Yuhui
Published: September 2024

During the later phase of reservoir development, the efficiency of water injection in wells declines, necessitating careful consideration of water injection methods and parameters. This study focuses on the Daqing Lamadian oilfield and investigates the strategy for dividing the stratified water injection layer section. The research takes into account several characterisation characteristics related to the physical attributes of the formation. Additionally, it establishes the methodology for calculating the boundaries of fluid volume in stratified water injection, taking into account various factors such as well distances, layer thicknesses, oil saturation, and others. The findings indicate that the extent of recovery diminishes as the coefficient of variation of seepage resistance within the water injection layer section increases. The most effective approach for segmenting the layers is by utilizing the coefficient of variation of seepage resistance. This method allows for the determination of the boundaries of the injection volume for various layers. The injection water volumes for different layer groups in the Lamadian oilfield are as follows: 1000 m3/d for S I, 9100 m3/d for S II, 4600 m3/d for S III, 1100 m3/d for P I, 4100 m3/d for P II, 2500 m3/d for G I, and 100 m3/d for G II. The results offer technical validation for the selection of injection parameters for well groups during the later stages of high water cut.
Adiabatic thermal runaway and safety relief design for hexamethylene diisocyanate reaction system
Authors: Liu Xin , Yang Xia , Tan Xinshun
Published: September 2024

Runaway reaction may occur for hexamethylene-diisocyanate (HDI) with two active NCO groups during the reactions or storage and transportation when run into device failure, operation error and other unexpected environments, which would damage equipment or even cause explosions. Adiabatic experiments for HDI using Vent Sizing Package 2 (VSP2) is conducted and temperature and pressure changes over time, as well as the maximum temperature rise rate and maximum pressure rise rate, are obtained. The results show that the initial exothermic temperature of the system is 50°C, and the maximum temperature is 232°C and the heat of reaction is 414.7 kJ/kg, so the severity level of HDI is classified as "medium" according to the assessment criteria for the severity of a runaway reaction. The relief type of the reaction system is determined to be a gas system by analysis of the pressure change curve during heating and cooling processes, along with the temperature at the point of loss of control, and calculated by the DIERS method and Leung's correction method through Python programming, which is applied to determine the required safety relief device for an industrial scenarios, and the minimum relief area is calculated to be 0.0028m2 and 0.0019m2, respectively. The study verifies the higher reliability of the safety relief design for runaway reactions based on VSP2 experimental data.
Research on the linkage technology of electric power operation field video and Beidou high-precision positioning terminal
Authors: Liu Ying , Huang Jeihui , Yan Chengbo , Wei Yihao , Miao Hao , Lian Weibing , Zheng Linsheng
Published: September 2024

In order to adapt to the trend of intelligent development in power operation sites and solve practical problems such as inadequate supervision of traditional power operation sites, this article mainly studies the linkage technology between power operation site videos and Beidou high-precision positioning terminals. Based on the application scenarios of the BeiDou positioning system in power operations, this paper summarizes the linkage technology between on-site video and BeiDou high-precision positioning terminals in power operations, and concludes that this technology is suitable for safety control of personnel in power operation sites, inspection and supervision of power lines, monitoring and early warning of inclined and collapsed transmission line towers. Research has found that the linkage technology between on-site video of power operations and Beidou high-precision positioning terminals can promote the intelligent development of power operations and achieve higher precision on-site control of power operations.
The Path Towards Green Transformation in Hainan's Manufacturing Sector
Authors: Zhang Meixuan , Tong Yun , Zeng Zhiren , Wang Jiayu
Published: September 2024

Under the inevitable choice of China's "dual carbon" strategy and ecological civilization construction, Hainan Province's free trade port adheres to green development. The green transformation of manufactory in Hainan Province is also active. Green transformation is influenced by multiple factors and involves the entire manufacturing cycle. Thus, this article first sorted out the 31 major categories of manufacturing in Hainan, calculated the average energy consumption of manufacturing enterprises above a certain scale, and obtained the basic situation of manufacturing enterprises in Hainan Province. This article also uses literature review to analyze the specific path of green transformation in Hainan Province's manufacturing industry from three aspects: government policies, industrial structure, and energy consumption. The research results found that there is a clear trend of green transformation in the manufacturing industry in Hainan Province. This article suggests that Hainan Province should expand the positive impact of policies such as free trade ports, promote digital and intelligent development, and continuously adjust industrial institutions.
The impact of energy on the development of human societies and the global economy
Authors: Bonhomme Gérard , Treiner Jacques
Published: September 2024

While the real weight of energy in the economy is still largely under-estimated in many macro-economic models, this article explains the strong interrelationship between energy, human development and the economy. Against a backdrop of growing global demand and the urgent need to decarbonise energy use, the article discusses a number of ways of reducing greenhouse gas emissions, based on technical innovations.
Energy Return On (energy) Invested (EROI) and its importance in assessing the performance of energy systems
Authors: Bonhomme Gérard , Treiner Jacques
Published: September 2024

Meeting the energy needs of our societies, in the context of the fight against global warming and the prospect of depleting stocks of fossil fuels and mineral resources, requires the implementation of low-carbon alternative solutions. The cost per MWh is undoubtedly a useful criterion, but physical criteria are essential for assessing technological solutions and possible energy scenarios.

The main of these criteria based on physical quantities is the “Energy Return on Invested” (EROI), which measures the efficiency of a system in providing society with useful energy for sectors other than the energy sector itself. Other aspects must also be considered, such as the availability of resources, the surface areas mobilised, mineral requirements, industrial risks and environmental and health impacts.
Making the most of nuclear heat
Authors: Leurent Martin , Safa Henri
Published: September 2024

Recovering some of the waste energy from nuclear power stations for industrial use or district heating offers very interesting prospects for reducing greenhouse gases (GHGs).
Molten salts for 4th generation nuclear reactors?
Authors: Merle Elsa , Allibert Michel , Heuer Daniel , Laureau Axel
Published: September 2024

If we are to combat climate change significantly, massive use of nuclear energy is essential. This requires upstream management of the risks associated with nuclear power and its acceptability to society. Nuclear generation will also have to be able to keep up with the load of a fleet that includes a large proportion of renewable energies.

This article presents and discusses a new approach to meeting these challenges: liquid fuel reactors, or molten salt reactors, which are attracting growing interest. It describes the developments made in France with the CNRS MSFR (molten salt reactor with fast neutron spectrum) concept, which offers prospects for the incineration of transuranics and the management of intermittent energy sources.
Digital is an increasingly heavy industry
Authors: Bidan Marc , Ferreboeuf Hugues , Marrauld Laurie , Rodhain Florence
Published: September 2024

Cloud computing and related practices are one of the most energy-intensive activities in the entire digital ecosystem.

On 10 March 2021, a fire completely destroyed one of the four Strasbourg data centres of OVH, the French leader in cloud computing. This unfortunate fire (see photo, p. 153) and its far-reaching consequences should encourage us to rethink the relationship between digital technology, the environment and our own sustainability. The damage and impact of this fire show that the cloud is not as ethereal as it seems. Quite the contrary. When the data centre burns down, it is indeed matter that burns. Our data is hosted and processed in factories, even if its physical reality, virtualised by marketing and media rhetoric, has become less and less perceptible to the end user.
The hidden costs of electricity
Authors: Percebois Jacques , Pommeret Stanislas
Published: September 2024

The price of electricity must take into account all the costs, both direct and induced, which are often hidden. This is true when calculating the average production cost per kWh at the power station. It is also true in the context of the operation of the wholesale electricity market based on the merit order, which leads to power stations being called on the basis of the marginal cost per kWh. Ignoring these hidden costs leads to distortions of competition and sub-optimal choices.
Efficacy and Safety of First-Line Palliative Chemotherapy with Fluorouracil Plus Leucovorin, Oxaliplatin, and Docetaxel (FLOT) in HER2-Negative Metastatic Gastric or Gastroesophageal Junction Adenocarcinoma: A Single-Institutional Real-World Experience from Eastern India
Authors: Chaudhuri Tamojit , Bankira Jaishree , Upadhyay Amitabh Kumar , Panda Rahul , Pandey Vanita , Mitra Sujata , Mukherjee Sopia
Published: September 2024

Background Fluorouracil plus leucovorin, oxaliplatin, and docetaxel (FLOT) is one of the preferred perioperative chemotherapy regimens in locally advanced resectable gastric cancer (GC). Till date, there are very few published data from India, regarding the outcomes of this relatively well-tolerated biweekly triplet regimen as first-line palliative chemotherapy in metastatic gastric or gastroesophageal junction (GEJ) adenocarcinoma.

Materials and Methods In the present retrospective study, we evaluated the efficacy and safety of first-line FLOT regimen in Indian patients with HER2-negative metastatic adenocarcinoma of stomach or GEJ. The primary endpoint was overall survival (OS). Progression-free survival (PFS), overall response rate (ORR), and toxicity profile were taken as secondary endpoints.

Results Between January 2021 and June 2024, 88 patients were treated with FLOT. The median age was 52 years (range, 23–68); 69.3% were males and 37.5% of the patients had ≥ 3 metastatic disease sites involvement at baseline. Dose reductions due to toxicity were required in 25% of the patients. The ORR was 68.2%; median PFS and OS were 6.3 months (95% confidence interval [CI]: 5.3–7.4) and 12.5 months (95% CI: 11.3–14.2), respectively. The most frequent grade 3 to 4 adverse events were diarrhea (15.9%), fatigue (13.6%), and neutropenia (12.5%). Younger patients (aged < 55 years) had much less ≥ grade 3 diarrhea (7.5%, n = 4), compared with patients aged ≥ 55 years (28.6%, n = 10). There was one toxicity-related death.

Conclusion In the present study, biweekly FLOT regimen with primary prophylactic granulocyte colony-stimulating factor demonstrated encouraging efficacy with a favorable nongastrointestinal toxicity profile in Indian patients with HER2-negative metastatic gastric or GEJ adenocarcinoma. Clearly, this well-tolerated triplet regimen should be explored further through large prospective randomized trials in Asian patients.
Electric charge-producing device offers new avenue for creating rain
Authors: Johnson-Groh Mara
Published: September 2024

To help address water scarcity issues, an electric charge-based cloud seeding device forecasts a different approach for inducing rainfall.
2D MoS2 plasmonic nanocavity based SERS platform for bilirubin detection
Authors: Maharana Akash Kumar , Tyagi Himanshu , Dash Sushree Tapaswini , Saha Puspita , Raturi Mamta , Saini Jyoti , Kaur Manpreet , Neeshu Km , Khan Rehan , Hazra Kiran Shankar
Published: September 2024

Although various methods can be used to detect bilirubin at the micromolar level, achieving reliable detection in the sub-nanomolar range remains challenging. Sensitivity at these ultralow levels is vital, as new evidence strongly associates bilirubin with chronic heart, lung, and neurological disorders. This accuracy is also essential for creating diagnostic protocols that can efficiently track bilirubin levels, assisting in managing related conditions. Such advancements will lead to enhanced diagnostic tools and methods, enabling more precise bilirubin monitoring in clinical environments. Here, the aforesaid blind-spot is addressed by utilizing surface enhanced Raman spectroscopy (SERS) as fingerprint technique to detect bilirubin concentrations as low as 0.1 nM. A plasmonically active 2D MoS2 based SERS substrate is formulated and optimized for single step SERS sensing of bilirubin. Plasmonic cavity based approach is utilized to circumvent the problem related to fluorescent background overwhelming the SERS signal. The 2D MoS2 based SERS platform shows threefold enhancement of scattering in comparison to the traditional gold nanoparticle on Si/SiO2 approach. The Raman signature of bilirubin is calibrated by taking citrate as a stable reference analyte and is shown to vary linearly with logarithmic concentration across the picomolar to micromolar range.
An advanced double-phase stacking ensemble technique with active learning classifier: Toward reliable disruption prediction in Aditya tokamak
Authors: Muruganandham Priyanka , Jayaraman Sangeetha , Tahiliani Kumudni , Tanna Rakesh , Ghosh Joydeep , Pathak Surya K , Ramaiya Nilam
Published: September 2024

Disruptions in tokamak nuclear reactors, where plasma confinement is suddenly lost, pose a serious threat to the reactor and its components. Classifying discharges as disruptive or non-disruptive is crucial for effective plasma operation and advanced prediction. Traditional disruption identification systems often struggle with noise, variability, and limited adaptability. To address these challenges, we propose an enhanced stacking generalization model called the “Double-Phase Stacking Technique” integrated with Pool-based Active Learning (DPST-PAL) for designing a robust classifier with minimal labor cost. This innovative approach improves classification accuracy and reliability using advanced data analysis techniques. We trained the DPST-PAL model on 162 diagnostic shots from the Aditya dataset, achieving a high accuracy of 98% and an F1-score of 0.99, surpassing conventional methods. Subsequently, the deep 1D convolutional predictor model is implemented and trained using the classified shots obtained from the DPST-PAL model to validate the reliability of the dataset, which is tested on 47 distinct shots. This model accurately predicts the disruptions 7–13 ms in advance with 93.6% accuracy and exhibited no premature alarms or misclassifications for our experimental shots.
Performance of antenna-based and Rydberg quantum RF sensors in the electrically small regime
Authors: Backes K. M. , Elgee P. K. , LeBlanc K.-J. , Fancher C. T. , Meyer D. H. , Kunz P. D. , Malvania N. , Nicolich K. L. , Hill J. C. , Marlow B. L. Schmittberger , Cox K. C.
Published: September 2024

Rydberg atom electric field sensors are tunable quantum sensors that can perform sensitive radio frequency measurements. Their qualities have piqued interest at longer wavelengths where their small size compares favorably to impedance-matched antennas. Here, we compare the signal detection sensitivity of cm-scale Rydberg sensors to similarly sized room-temperature electrically small antennas with active and passive receiver backends. We present and analyze effective circuit models for each sensor type, facilitating a fair sensitivity comparison for cm-scale sensors. We calculate that contemporary Rydberg sensor implementations are less sensitive than unmatched antennas with active amplification. However, we find that idealized Rydberg sensors operating with a maximized atom number and at the standard quantum limit may perform well beyond the capabilities of antenna-based sensors at room temperature, the sensitivities of both lying below typical atmospheric background noise.
Wave excited motion of a body floating on water confined between a semi-infinite ice sheet and a side wall
Authors: Wang Chunhui , Xiao Runshan , Wang Jiaan , Wang Chao , Yu Fajun
Published: September 2024

In this paper, we investigate the diffraction and radiation coupling problem of a floating body confined between a fixed wall and a semi-infinite ice sheet under the action of incident waves. Based on the linear water wave theory and Kirchhoff Love elastic thin plate assumption, the ice sheet is considered as an elastic beam, and the boundary conditions of fluid boundaries covered by the ice sheet are obtained. Dividing flow domains with different upper surfaces, the eigenfunction expansion method was used to obtain the velocity potential expansion equations for each sub-domain. Then, through the matching conditions at the interface of sub-domains, a system of equations was constructed to solve the unknown coefficients of the expansion equations. The influence of the existence of the ice sheet on the diffraction and radiation motion of the floating body is analyzed. The effects of changes in the draft and open water width of the floating body on the wave excitation force and hydrodynamic coefficient of the floating body are discussed. The influence of the reflection effect of the ice sheet on the added mass and damping coefficient of the floating body has been discovered, especially the changes and oscillation rules of their extreme points. This research achievement provides theoretical support for the safety design of floating structures in frozen harbors.
Thermal convection subjected to perturbations from the bottom of a top open cavity
Authors: Qiao Manman , Jiang Feng , Gao Zhu , Xu Mengfan , Yu Tianchong , Li Shiyang , Zhang Hongsheng , Xu Feng
Published: September 2024

Perturbations are very common in the transition and heat transfer of thermal convection in nature and industry. Accordingly, thermal convection on a top-open cavity subjected to periodic and random perturbations is investigated using three-dimensional numerical simulation. A great number of numerical experiments are performed at various Rayleigh numbers and a fixed Prandtl number of 0.71 by introducing periodic and random numerical perturbations. Numerical results demonstrate that there exists the effect of periodic perturbations on the transition route over 3.5 × 103 ≤ Ra ≤ 8.5 × 104. That is, the transition route to chaos is sensitive to the amplitude of random perturbations for, e.g., 0.01 ≤ Ar ≤ 0.05, which is also characterized. Furthermore, heat transfer enhancement under periodic and random perturbations is quantified with the scaling law. This study sheds new light on the influence of periodic and random perturbations on thermal convection on the top-open cavity below heating. The possibility to control heat transfer is revealed by introducing random perturbations on the bottom of the top-open cavity.
Symbolic extended dynamic mode decomposition
Authors: Kennedy Connor , Kaushagen John , Zhang Hong-Kun
Published: September 2024

In this paper, we present a new method of performing extended dynamic mode decomposition (EDMD) on systems, which admit a symbolic representation. EDMD generates estimates of the Koopman operator, K, for a dynamical system by defining a dictionary of observables on the space and producing an estimate, Km, which is restricted to be invariant on the span of this dictionary. A central question for the EDMD is what should the dictionary be? We consider a class of chaotic dynamical systems with a known or estimable generating partition. For these systems, we construct an effective dictionary from indicators of the “cylinder sets,” which arise in defining the “symbolic system” from the generating partition. We prove strong operator topology convergence for both the projection onto the span of our dictionary and for Km. We also prove practical finite-step estimation bounds for the projection and Km as well. Finally, we demonstrate some numerical results on eigenspectrum estimation and forecasting applied to the dyadic map and the logistic map.
Three-dimensional wake transition of rectangular cylinders and temporal prediction of flow patterns based on a machine learning algorithm
Authors: Mashhadi A. , Sohankar A. , Moradmand M. M.
Published: September 2024

This study investigates the three-dimensional (3D) wake transition in unconfined flows over rectangular cylinders using direct numerical simulation (DNS). Two different cross-sectional aspect ratios (AR) and Reynolds numbers (Re) are scrutinized: AR = 0.5 at Re = 200 and AR = 3 at Re = 600. The investigation focuses on characterizing the flow patterns and forecasting their temporal evolution utilizing the proper orthogonal decomposition (POD) technique coupled with a long short-term memory (LSTM) network. The DNS results reveal the emergence of an ordered mode A for AR = 3, attributed to the stabilizing effect of the elongated AR. On the other hand, the case with a smaller AR (= 0.5) exhibits a mode-swapping regime characterized by modes A and B's distinct and simultaneous manifestation. The spanwise wavelengths of mode A and mode B are approximately 4.7 and 1.2 D for AR = 0.5, while the spanwise wavelength of mode A is 3.5 D for AR = 3. The POD serves as a dimensionality reduction technique, and LSTM facilitates temporal prediction. This algorithm demonstrates satisfactory performance in predicting the flow patterns, including the instabilities of modes A and B, across both transverse and spanwise directions. The employed algorithm adeptly predicts the pressure time series surrounding the cylinders. The duration for training the algorithm is only about 0.5% of the time required for DNS computations. This research, for the first time, demonstrates the effectiveness of the POD–LSTM algorithm in predicting complex 3D instantaneous wake transition patterns for flow past rectangular cylinders.
Residual-based reduced order models for parameterized Navier–Stokes equations with nonhomogeneous boundary condition
Authors: Zhang Tao , Xu Hui , Zhang Yan , Feng Xinlong
Published: September 2024

In this paper, we propose a residual-based reduced-order model (ROM) framework that utilizes available data to increase the ROM accuracy and stability. The available snapshots are utilized to obtain the original ROM systems and their projection coefficients by performing proper orthogonal decomposition. Then a time-parameter varying closure term is added to the original ROM systems to obtain the new ROM systems, and the values of the closure term at discrete time-parameter points with respect to snapshots are evaluated by computing the residual of the original ROM systems with projection coefficients. In an online testing stage, the values of the closure term at unknown time-parameter points are approximated by linear interpolation, and the new ROM systems are utilized to approximate solutions for unseen parameter values. In addition, the closure term in the new ROM systems is instead discarded when we predict systems' evolution outside the time interval with respect to snapshots. Numerical results show that the proposed method not only improves the prediction accuracy of original ROM but also extends the applicability of it.
Thermally induced oscillatory rarefied gas flow inside a rectangular cavity
Authors: Yang Weiqi , Xu Bowen , Niu Yaobin , Zhou Yunfan
Published: September 2024

Thermally induced oscillatory rarefied gas flow inside a two-dimensional rectangular cavity is investigated based on the hybrid macro-/mesoscopic scheme. The effects of the Knudsen (Kn) numbers and the oscillation frequency of lid temperature on the flow parameters are analyzed. The Shakhov model equation is solved numerically based on the mesoscopic approach in the near-wall region, and the macroscopic approach is adopted in the bulk flow region to reduce the computational cost. To close the numerical iteration procedure, the velocity distribution functions serving as the pseudo boundary between macroscopic and mesoscopic methods are reconstructed using the high-order Hermite polynomials. Numerical simulations demonstrate that the temperature profile at the central vertical of the cavity predicted by the hybrid method is in good agreement with results from the mesoscopic method, with a maximum error of 0.23%. In addition, the computational memory cost can be saved up to about 69.91%. The hybrid approach is able to capture the nonlinear phenomenon in the thermally induced oscillatory rarefied gas flow under high Kn numbers, where the horizontal velocity no longer obeys the law of periodic oscillating cosine function, and the rise time of the horizontal velocity is much longer than the fall time. The thickness of the viscous penetration layer and the disturbed region increases as the Kn number increases and decreases as the Strouhal number increases.
A novel framework of the lattice Boltzmann model for multilayer shallow water systems
Authors: Ru Zhiming , Liu Haifei , Yang Wei , Leng Fei
Published: September 2024

This study proposes a novel framework of the lattice Boltzmann model for multilayer shallow water equations, considering the mass and momentum exchanges between layers (LABMSWE+). Compared with the original LABMSWE model consisting of N two-dimensional lattice Boltzmann method for shallow water equation (LABSWE) models, the new model includes 1+N LABSWE models. The singular LABSWE model with unit relaxation time is introduced to update the total water depth, and thus, the layer water depths can be obtained explicitly through the fixed layer ratios. The N-layer LABSWE models with the multiple-relaxation-time operator evolve the layer velocities. These two modules are coupled by the total water depth and depth-averaged velocities. The constructed model avoids the freely variable layer thicknesses, which is considered as the main source of the instability. In addition, the mass exchanges enable this model to simulate vertical circulation flows, which are beyond the application of the LABMSWE model. Several numerical tests are then conducted to validate the proposed model. The results show that it exactly satisfies the C-property. In addition, the central difference scheme is more stable and accurate than the upwind and nonequilibrium schemes in the computing of the mass exchanges. The numerical results have an excellent agreement with analytical solutions and reference data, while some unstable and nonphysical results are obtained by the original LABMSWE model. Moreover, the computational time is about 40%–60% of that for the MIKE3, a finite volume solver for the three-dimensional shallow water equations by the Danish Hydraulic Institute.
A two-cell vortex model
Authors: Aboelkassem Yasser
Published: September 2024

A two-cell vortex solution to the Navier–Stokes equations is derived in this article. The theoretical analysis provides expressions for the velocity components, vorticity, and pressure distributions of the two-cell vortex flow. A key feature of this new modeling approach is the presence of a “vortex eye” region, which is absent in classical single-cell vortex models. The derived tangential velocity profile is kept general, allowing for the recovery of the single-cell profile as a special case. The model parameters are constrained by the boundary conditions inherent to two-cell vortices. The model explicitly demonstrates that the two-cell vortex flow exhibits two regions of recirculating flow structures in the meridional plane. The analysis shows that near the vortex core, fluid descends from above and diverges outward. This downward flow meets the incoming flow from the vortex's outer region at a distance known as the “eye-wall” radius. The merging of these two streams results in an upward deflection, generating the two-cell fluid motion. Unlike in single-cell vortices, where vorticity reaches its maximum at the vortex center, the present results indicate that in two-cell vortices, the vorticity peaks at the eye-wall radius.
Cryogenically cooled periodically poled lithium niobate wafer stacks for multi-cycle terahertz pulses
Authors: Dalton P. J. , Shaw C. T. , Bradbury J. T. , Mosley C. D. W. , Sharma A. , Gupta V. , Bohus J. , Gupta A. , Son J.-G. , Fülöp J. A. , Appleby R. B. , Burt G. , Jamison S. P. , Hibberd M. T. , Graham D. M.
Published: September 2024

We report on the generation of high-power narrow-bandwidth terahertz (THz) pulses by cryogenic cooling of hand-made periodically poled lithium niobate (PPLN) wafer stacks. As a proof-of-concept, we cool stacks with up to 48 wafers down to 97 K and achieve few-percent bandwidths at a center frequency of 0.39 THz, with pulse energy up to 0.42 mJ and average power of 21 mW. Supported by modeling, we observe effective cooling of PPLN wafer stacks that not only reduces terahertz absorption but critically maintains the micrometer-scale inter-wafer gaps for optimal terahertz transmission. Our results unlock the potential for scaling these large-area sources to greater numbers of wafers to push both the energy and bandwidth beyond current capability, opening up possibilities in areas such as terahertz-driven particle acceleration, terahertz imaging, and control over material properties.
Centerline shock reflection for supersonic internal flows in the non-Rankine-Hugoniot zone: Overexpanded supersonic microjets
Authors: Hew Justin Kin Jun , Ogawa Hideaki , Boswell Rod W.
Published: September 2024

The viscous and rarefaction effects on centerline shock reflection occurring in an overexpanded axisymmetric microjet have been investigated numerically by means of a fully coupled pressure-based shock capturing scheme. Due to the low free-stream Reynolds number, the Navier–Stokes equations were coupled with slip velocity and temperature jump boundary conditions to account for rarefied gas effects in the Knudsen layer. It has been found that pronounced viscosity levels can cause a transition from a three-shock to a two-shock configuration, which is impermissible by inviscid theory. This is the first observation of such phenomena in the case of over-expanded jets. Analysis of the von Neumann and detachment criteria indicates that the transition from Mach reflection to regular reflection is analogous to the dual-solution domain transition for planar shocks. In addition, prediction of the longitudinal curvature of the incident shock has been conducted from a mathematical standpoint.
Change of composition and surface plasmon resonance of Pd/Au core/shell nanoparticles triggered by CO adsorption
Authors: Ouvrard Aimeric , Alyabyeva Natalia , Zakaria Abdoul-Mouize , Yuan Keke , Dablemont Céline , Lazzari Rémi , Charra Fabrice , Bourguignon Bernard
Published: September 2024

Controlling composition and plasmonic response of bimetallic nanoparticles (NPs) is of great relevance to tune their catalytic activity. Herein, we demonstrate reversible composition and plasmonic response transitions from a core/shell to a bimetallic alloyed palladium/gold NP triggered by CO adsorption and sample temperature. The use of self-organized growth on alumina template film allows scrutinizing the impact of core size and shell thickness onto NP geometry and plasmonic response. Topography, molecular adsorption, and plasmonic response are addressed by scanning tunneling microscopy, vibrational sum frequency generation (SFG) spectroscopy, and surface differential reflectance spectroscopy, respectively. Modeling CO dipolar interaction and optical reflectivity corroborate the experimental findings. We demonstrate that probing CO adsorption sites by SFG is a remarkably sensitive and relevant method to investigate shell composition and follow in real-time Pd atom migration between the core and the shell. Pd–Au alloying is limited to the first two monolayers of the shell and no plasmonic response is found, while for a thicker shell, a plasmonic response is observed, concomitant with a lower Pd concentration in the shell. Above 10−4 mbar, at room temperature, CO adsorption triggers the shell restructuration, forming a Pd–Au alloy that weakens the plasmonic response via Pd migration from the core to the shell. NP annealing at 550 K, after pumping CO, leads to the desorption of remaining CO and gives enough mobility for Pd to migrate back inside the core and recover a pure gold shell with its original plasmonic response. This work demonstrates that surface stoichiometry and plasmonic response can be tuned by using CO adsorption and NP annealing.
Nonlinear model reduction from equations and data
Authors: Pagliantini Cecilia , Jain Shobhit
Published: September 2024

Modeling in applied science and engineering targets increasingly ambitious objectives, which typically yield increasingly complex models. Despite major advances in computations, simulating such models with exceedingly high dimensions remains a challenge. Even if technically feasible, numerical simulations on such high-dimensional problems do not necessarily give the simplified insight into these phenomena that motivated their initial models. Reduced-order models hold more promise for a quick assessment of changes under parameters and uncertainties, as well as for effective prediction and control. Such models are also highly desirable for systems that are only known in the form of data sets. This focus issue will survey the latest trends in nonlinear model reduction for equations and data sets across various fields of applications, ranging from computational to theoretical aspects.
Ru/MgO-catalysed selective aerobic oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid
Authors: Lokhande Priya , Dhepe Paresh L. , Wilson Karen , Lee Adam F.
Published: September 2024

Biomass valorisation through the selective oxidation of carbohydrate and lipid derivatives offers access to an array of platform chemicals through energy- and atom-efficient catalytic processes. Supported metal nanoparticles are promising catalysts for the aerobic selective oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA), but typically require strong liquid base to achieve high selectivity. Here, we explore the utility of MgO as a solid base support for the Ru-catalysed aerobic oxidation of HMF, obtaining 68% FDCA yield at 160°C and 1.5 MPa of O2 using <1 mol-% metal.