bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of a microfurnace dedicated to in situ scanning electron microscope observation up to 1300 °C. II. Study of the thermal response of samples
Authors: Mendonça Jérôme , Brau Henri-Pierre , Nogues Dorian , Candeias Antoine , Podor Renaud
Published: May 2024

When conducting in situ experiments at high temperatures in a scanning electron microscope using microfurnaces, controlling the temperature of a sample of a few mm3 placed in the hot zone of the furnace can be a complex task. In most cases, the temperature of the sample is estimated by means of a thermocouple placed in the hot body of the furnace, and the assumption made is that the temperature of the furnace is the temperature of the sample. In this work, a detailed understanding of the thermal response of the sample placed in the hot zone of the furnace is proposed. Temperature differences due to contact resistance between the furnace surface and the sample, the nature of the sample, and the sample geometry are calculated with a numerical model and measured experimentally on a dedicated test bench. Three technical solutions (bonding, sandwiching, and mini-crucible) for limiting temperature differences between the furnace surface and sample are proposed and validated by numerical calculations and experimental measurements.
Sufficient and necessary criteria for backward asymptotic autonomy of pullback attractors with applications to retarded sine-Gordon lattice systems
Authors: Yang Shuang , Caraballo Tomás , Zhang Qiangheng
Published: May 2024

In this paper, we investigate the backward asymptotic autonomy of pullback attractors for asymptotically autonomous processes. Namely, time-components of the pullback attractors semi-converge to the global attractors of the corresponding limiting semigroups as the time-parameter goes to negative infinity. The present article is divided into two parts: theories and applications. In the theoretical part, we establish a sufficient and necessary criterion with respect to the backward asymptotic autonomy via backward compactness of pullback attractors. Moreover, this backward asymptotic autonomy is considered by the periodicity of pullback attractors. As for the applications part, we apply the abstract results to non-autonomous retarded sine-Gordon lattice systems. By backward uniform tail-estimates of solutions, we prove the existence of a pullback and global attractor for such lattice systems such that the backward asymptotic autonomy is satisfied. Furthermore, it is also fulfilled under the assumptions of the periodicity for the non-delay forcing and the convergence for processes.
Deterioration evolution mechanism and damage constitutive model improvement of sandstone–coal composite samples under the effect of repeated immersion
Authors: Jiang Tianqi , Zhu Chun , Qiao Yang , Sasaoka Takashi , Shimada Hideki , Hamanaka Akihiro , Li Wei , Chen Bingbing
Published: May 2024

Underground reservoirs in coal mines, consisting of goafs (By goaf, we mean the space that remains underground after the extraction of valuable minerals), are commonly utilized for mine water storage and drainage, with their primary load-bearing structures being the “roof–coal pillar” systems. Consequently, this structure must endure the repeated immersion behavior resulting from fluctuations in the mine water level, resulting in the risk of geological disasters. This paper analyzes the variation in mechanical properties of sandstone–coal composite samples after repeated immersion cycles through axial loading tests. The results indicate that the water content of the sample exhibits a notable and rapid increase with each successive immersion cycle. This corresponds to a decrease in the stress threshold and modulus parameters of the samples. Moreover, the acoustic emission signals serve as indicators of the softening characteristics of the samples. With the increase in immersion cycles, there is an augmentation in both the frequency and extent of shear cracks. The non-linear failure characteristics of the samples become more pronounced. Consequently, water significantly weakens the cementing material between rock grains. Both sandstone and coal display a decrease in deformation resistance capabilities at a macroscopic level. The constitutive model of the composite sample was improved based on the degradation characteristics of mechanical strength and strain energy parameters, which offers enhanced accuracy in analyzing the degradation process caused by water immersion. This paper offers a crucial theoretical foundation for comprehending the deterioration evolution characteristics of the “roof–coal pillar” bearing structure affected by repeated immersion.
Experimental study on impact icing of the superhydrophobic surfaces with cruciferous bionic structure
Authors: Zhou Jiahui , Zheng Haikun , Chen Xiaosong , Han Xu , Zhao Zhengqiang , Sheng Wei , Zhang Xinmin
Published: May 2024

Superhydrophobic surfaces have been extensively utilized due to their high hydrophobicity and anti-icing properties. Inspired by the shape of a cross flower, research has utilized circular arc curves and Bessel curves to design a cross flower structure model. Using 3D modeling software for modeling and 3D printing technology to prepare biomimetic microstructures in structural design. The structural shape of the microstructure before and after spray coating was detected using ultra depth of field and laser confocal microscopy. Using Ultra-Ever Dry as a low surface energy substance to alter the wettability of microstructure surfaces. Through surface wettability tests, droplet freezing, and droplet impact tests, the cross shaped biomimetic structure designed by the Bessel curve has a maximum droplet freezing time of 4193 s and a minimum droplet impact time of 9.81 ms. The experimental results indicate that the cross shaped biomimetic structure has good hydrophobicity and broad application prospects.
Symmetry breaking charge transfer and control of the transition dipole moment in excited octupolar molecules
Authors: Siplivy Nikolay B. , Ivanov Anatoly I.
Published: May 2024

The structure of the energy levels of excited symmetric donor–acceptor octupolar molecules suggests a completely symmetric state and a degenerate doublet. For most molecules, the doublet is the first excited state, which is called the normal level order, but there are molecules with the reverse level order. Symmetry breaking charge transfer (SBCT) and its effect on the transient dipole moment in these structures are studied. It has been established that for reverse level order, SBCT is possible only if the reorganization energy exceeds a certain threshold, whereas for the normal level order, there is no such threshold. The lowest completely symmetric excited state is shown to become bright after SBCT. The dependence of the fluorescence transition dipole moment on the SBCT extent is calculated. It was established that the direction and magnitude of the transition dipole moment change similarly to the change in the dipole moment for the reverse level order, whereas for the normal level order, the changes are opposite. The effect of solvent thermal fluctuations on the transition dipole moment is simulated and discussed. A way for controlling the direction of the transition dipole moment by an external electric field is suggested.
Unveiling the pressure-induced scheelite to M′-fergusonite phase transition in NaCe(MoO4)2
Authors: Ferreira W. C. , Alabarse F. G. , Luz-Lima C. , Silva R. S. , Olivier L. S. A. , Freire P. T. C. , Lima J. A. , Moura J. V. B.
Published: May 2024

Sodium-cerium molybdate, NaCe(MoO4)2, belongs to the family of double alkaline rare-earth molybdate, and it holds significant importance across various technological domains, such as environmental remediation and energy conversion. Despite its importance, the behavior of NaCe(MoO4)2 under high-pressure conditions remains unexplored. This study uses synchrotron x-ray diffraction and Raman spectroscopy to investigate NaCe(MoO4)2in situ under high-pressure conditions. We observed a pressure-induced phase transition from the scheelite to the M′-fergusonite structure type on a double molybdate at approximately 10 GPa. These findings contribute to a deeper understanding of the structural stability of NaCe(MoO4)2 and shed light on the broader field of high-pressure studies of double molybdates.
Exploring innovation in operations – the Multi-user Remote Operations Centre (MROC) concept
Authors: Beales Jonathan
Published: May 2024

For new energy products to compete with hydrocarbons, the cost to the consumer must be equivalent or lower. To achieve this, producers require operational excellence at lowest possible cost. Innovation and improvements in data processing through the deployment of ‘intelligent’ software is just one of many solutions that can deliver this. Petrofac is constantly developing and applying innovative approaches in the energy landscape, the concept of a Multi-user Remote Operations Centre (MROC) is an extension of this innovation stream. It has been envisioned to lower capital expenditure (CapEx) and operational expenditure (OpEx) for both new market entrants and facilities and to improve safety and reduce emissions. The MROC is a purpose-built operating centre cluster that co-locates facilities such as the central control room, emergency response (ER), and engineering support. It would be owned and financed by a third party, the service provider would lease control facilities to separate clients and provide support services as necessary. This would allow multiple operators to unlock the financial, operational, safety and environmental benefits of remote operation without incurring the significant CapEx outlay normally associated with it. The number of personnel travelling to and from remote facilities would reduce, in turn reducing exposure to safety risks and lowering Scope III emissions. The MROC concept is particularly suited to Australia due to our geography and number of remote assets but could be adapted for other locations. The co-location of operation support engineering, procurement and ER would lead to increased business efficiencies, which would be reflected in a lower production cost.
Leadership and talent attraction and retention – an existential risk to our industry
Authors: Hastie Scott
Published: May 2024

Political, social, shareholder – and increasingly talent – pressure is driving a seismic shift as oil and gas operators are required to transform into diversified energy companies. Attracting and retaining the required leadership and talent to drive this transformation is an existential risk to our industry. 10.5% of the total workforce left the industry during the 2019/2020 oil price crash. Since 2020 the experienced oil and gas industry workforce has aged and will take critical skills and experience with them into retirement. 40% of Australian oil and gas recruiters believe retaining this knowledge and replacing these skills are the industry’s biggest challenges. In parallel, events in August 2023 in Western Australia have demonstrated the immediate market impact workforce unrest can have. Concurrently, it is becoming harder to attract talent to the industry. The competition for adaptive leaders and high-skilled workers has been accentuated as the oil and gas sector continues to evolve and now competes for these skills sets with other industries. Environmental, Social and Governance (ESG) performance is increasingly becoming an important factor in the industry’s ability to attract and retain talent. In a recent global talent index report, 85% of respondents stated ESG is a factor in whether they will stay or leave an oil and gas organisation. Interestingly, 55% of those open to switching sectors would be interested in switching to renewables. In this paper, I provide oil and gas companies with pragmatic guidance on how to quantify the impact of these challenges, adapt the industry narrative, and re-position as an employer of choice.
Ramsay 1 and Ramsay 2, learnings from the first natural hydrogen exploration wells in Australia
Authors: Whitcombe Josh , McDonald Neil , Cressey Roger , Hadi Subrata Billy , Falloon Steve , Carr Neil , Glass Frank
Published: May 2024

In October and November 2023, Gold Hydrogen, an ASX listed natural hydrogen explorer, drilled Ramsay 1 and Ramsay 2, the first natural hydrogen exploration wells in Australia. Twinning an historic well, the Ramsay Oil Bore 1 well in PEL687 in South Australia, the objective of the Ramsay 1 and Ramsay 2 wells was to find movable naturally generated hydrogen in the subsurface and establish the presence of a commercially attractive natural hydrogen resource base. This paper highlights some of the learnings from the process of designing and executing these natural hydrogen exploration wells and how the initial hurdles of demonstrating the presence of a hydrogen resource were overcome during the drilling phase. Using modified standard drilling technology and dedicated hydrogen detection tools (calibrated real time mud gas analysis), Gold Hydrogen has shown that exploration for natural hydrogen resources can be done safely and cost effectively. The main learnings included the application of a calibrated hydrogen detection methodology to derive a pseudo hydrogen saturation log and the successful selection of drilling mud and casing compliant with long term hydrogen exposure. As global drilling for natural hydrogen is still in its infancy, these modifications to the exploration well design and execution could have a significant impact on future drilling for this highly attractive carbon free energy source. With a program of seismic data acquisition and follow-up wells planned for 2024, Gold Hydrogen is leading a group of Australian natural hydrogen explorers, who are trying to unlock commercial natural hydrogen resources in the world.
The impact of exploration/appraisal activities on the recovery per well in North Perth Basin
Authors: Wu Hongfeng , Glass Frank , Storey Martin , Molyneux Simon , Walton William
Published: May 2024

The North Perth Basin (NPB) in Western Australia has experienced significant petroleum industry activity over the past 3 years (2021–2023), marked by the drilling of exploration and appraisal wells by various operators, along with notable merger and acquisition transactions. This flurry of drilling activity, coupled with the acquisition of new seismic data, have enhanced our understanding of the variability within the primary petroleum play levels – namely, the Permian ‘Kingia’ and High Cliff reservoirs. This understanding is crucial for assessing the future potential of domestic gas supply in Western Australia. This paper aims to elucidate how recent drilling efforts have narrowed the basin-wide portfolio of available gas prospects relative to the situation in early 2021, and how the landscape of undiscovered gas resources has evolved. This shift is attributed to both unsuccessful exploration attempts and revised estimates of well deliverability. Furthermore, an updated long-term production forecast for the NPB – considering existing gas pools and the newly assessed undiscovered resources – emphasises the urgent need to re-evaluate the narrative concerning gas availability for the domestic market. The Permian gas plays within the NPB have proven to be more intricate and unpredictable than previously believed. Nonetheless, their significance to the Western Australian economy is anticipated to be substantial for many years ahead.
Don’t forget your keys when trying to unlock the productivity of low-permeability coals
Authors: Johnson Raymond L.
Published: May 2024

Low-permeability coal seam gas (CSG) wells have been the subject of laboratory research and modelling studies over the past decade, particularly focusing on the pressure-dependent permeability (PDP) behaviour of coals. These research efforts have progressed diagnostic methods to identify and quantify PDP and provide practical technologies to counter these effects. Firstly, machine learning methods based on drilling and historical well-test data can provide insight into the range of coal permeability during drilling. Next, the process of history-matching the after-closure pressures from a diagnostic fracture injection test (DFIT), using reservoir simulators, can determine best-fit values for fracture compressibility, a key parameter for reservoir models. Finally, these data, along with DFIT reservoir pressure and permeability data, can inform the decision-making process regarding the most applicable completion strategy and aid developmental planning. For areas where vertical or surface-to-inseam (SIS) wells have been unsuccessful, new hydraulic fracturing technologies have been developed to enhance the stimulated reservoir volume (SRV) in coals, using horizontal wells with multi-stage hydraulic fracturing in excess of 20 stages. Recent laboratory and modelling of micro-proppants has extended prior laboratory and modelling studies and provided insight into proppant transport, embedment, and screen-out behaviour. These well stimulation technologies can be co-applied in new or existing CSG fields and are suitable for areas where overlapping tenements limit conventional, steel-based completion strategies. In conclusion, this paper will bring the key findings of these studies together in a cohesive framework and provide the workflows to implement these technologies for better productivity in low-permeability coals.
Chemostratigraphy of the Sherbrook Supersequence – 13 wells from the offshore Otway Basin
Authors: Gunning Merrie-Ellen , Nguyen Duy , Riley David , Tansell Clare , Bufarale Giada
Published: May 2024

An elemental chemostratigraphic study of the offshore Otway Basin has been undertaken as part of a collaboration between Chemostrat and Geoscience Australia, the main aim of which is to better constrain the sequence boundaries of, and within, the Sherbrook Supersequence. This study includes the elemental analysis of 1185 cuttings samples from the Sherbrook Supersequence (and overlying stratigraphy) in 13 offshore wells. Sampling of cuttings was particularly challenging as many of the targeted wells have a paucity of material available for destructive analysis. Inductively Coupled Plasma-Optical Emission Spectrometry and Mass Spectrometry (ICP-OES and MS) analysis was undertaken to establish a regional elemental chemostratigraphic framework of the Sherbrook Supersequence. The resultant framework comprises two chemostratigraphic sequences, seven chemostratigraphic packages and eighteen chemostratigraphic units. While the analysis could not clearly distinguish the base of the Sherbrook Supersequence it has provided valuable insight into correlations between wells, within the Sherbrook and overlying Wangerrip supersequences. Importantly it has confirmed that in the offshore part of the basin sedimentary processes and inputs remain unchanged from the Shipwreck to the Sherbrook (Turonian–Maastrichtian).
The Australian Hydrogen Centre – feasibility studies for achieving 10 and 100% renewable hydrogen in South Australia and Victoria
Authors: Sharpe Owen , Raman Kristin
Published: May 2024

The Australian Hydrogen Centre (AHC) was established to deliver Australian-first feasibility studies into how existing natural gas distribution networks could be used in a system to produce, store, and transport renewable hydrogen, decarbonising gas supply while still meeting the needs of customers. The AHC Reports show that it is technically and economically feasible to use existing gas infrastructure for scaled hydrogen distribution, delivering: (1) net-zero carbon emissions gas; (2) minimised customer disruption while retaining security and diversity of supply; (3) services to the electricity grid through flexible electricity demand and frequency control; (4) 15 gigawatts (GW) of electrolysis supported by over 30 GW of new renewable electricity generation; (5) 30 petajoules (PJ) of hydrogen storage to harness the ability of gas to store vast amounts of energy, balancing renewable electricity supply and demand swings between colder and warmer months; and (6) over AU$1.5 billion in additional economic value a year including more than 12,500 jobs during construction and 6200 jobs during operation. Supported by a range of independent technical studies, the Reports provide a better understanding of the opportunity to access Australia’s world-class gas distribution infrastructure to unlock hydrogen opportunities while retaining energy security and affordability; identifying a range of low-regret enablers that could trigger coordinated action by government and industry. They also share learnings from Hydrogen Park South Australia (HyP SA), an Australian-first demonstration of hydrogen blending in a gas distribution network.
Reliable local renewable power decarbonising offshore energy
Authors: Silva Ana , Yuill Lorna
Published: May 2024

Reliable local renewable power generation enables more environmentally and economically viable operations, to meet with the challenge of renewable energy intermittency and energy security. The Renewables for Subsea Power (RSP) project support targets towards Net Zero Targets by providing a full solution to generate low carbon, cost-effective, power and communications to remote locations in the offshore energy industry. The development of the RSP system is a collaborative project led by three UK-based companies in partnership with wider industry engagement from operators and the Aberdeen-based Net Zero Technology Centre. Carbon capture, utilisation and storage (CCUS) is set to play a key role in the energy transition. CCUS developments will incorporate all-electric subsea systems that can benefit from the RSP solution. This first of a kind integrated solution will contribute significantly to the generation of clean energy in the petroleum industry using a Wave Energy Converter and seabed battery energy storage for production control applications. The various applications that would benefit from the cost and CO2 savings from deploying the system, compared to traditional methods, include umbilical remediation, brownfield expansion, long offsets, CCUS, and Autonomous Underwater Vehicle residency. For CCUS projects key advantages are a specific design catered towards simplified controls architecture (e.g. electric controls), and the ability to offer an alternative to direct current fibre-optic from shore. A full system demonstrator deployment commenced in Feb-23 and has demonstrated system capability to power subsea equipment and an Autonomous Underwater Vehicle (AUV). Trials continue through 2024.
Adapting to thrive in the new energy market
Authors: Bennett Peter
Published: May 2024

This paper is not published because no presentation was made at the Australian Energy Producers Conference 2024.
Planning for complex decommissioning projects in Australia – Gippsland Basin case study
Authors: Perry Richard
Published: May 2024

Over more than 50 years, safe and successful installation projects have enabled progressive development and expansion of the Gippsland Basin Joint Venture off the coast of Victoria, Australia. This has resulted in a highly integrated network of 19 offshore platforms which are now starting to progressively reach the end of their productive life and detailed planning for the first phase of decommissioning projects has increased in intensity. Decommissioning of these assets is planned to take place in a number of campaigns. The Campaign 1 Decommissioning Project includes the removal of up to 13 platforms and is likely to be the largest single project of its kind in the World. Experience of similar decommissioning projects in Australia is very limited, resulting in unprecedented challenges across many aspects of this project. This requires creative, innovative and adaptable solutions to be developed to enable an efficient execution methodology. This paper will explore the strategies, challenges and successes involved with the early planning and development phase of the Gippsland Basin Joint Venture, Campaign 1 Decommissioning Project. Key insights, from contracting, to execution planning and stakeholder engagement will be discussed, promoting sharing across the industry and improving efficiency for future decommissioning projects in Australia.
2023 Development and production review
Authors: Wilkes Martin
Published: May 2024

Geopolitical uncertainty remained high in 2023 with Israeli actions in the Gaza strip, the continuing war in Ukraine and tension between China and several neighbouring countries. However, global inflationary pressures, surprisingly, eased during the year, and the prospect of a global recession faded from where it had been in 2022. In Australia continued activism around climate change issues, has impacted project developments and sentiment in the industry remained subdued. This paper looks back at the oil and gas production and development activities in Australia in 2023 providing historical context and trying to understand future implications for the industry. Liquefied natural gas (LNG) production in Australia remained close to record high levels although, not without problems. Both the Scarborough/Pluto 2 LNG project and the Barossa project continued to have legal and approval hurdles resulting in suspension of some execution activities. Elsewhere other projects continued with their plans, including the Kipper field in the Gippsland Basin, the Crux project in the Browse Basin and the Walyering project in the Perth Basin which was brought online in September 2023. The domestic markets also continued to have unique issues with major concerns about gas supply in the East, stalled developments and failing supply in the Northern Territory, and a renewed ban on any exports (including to other states) of gas from Western Australia.
Extended analysis of solid cancer incidence among nuclear industry workers in the UK 1955–2011: comparison of workers first hired in earlier and later periods
Authors: Hunter Nezahat , Haylock Richard
Published: May 2024

To address points arising from the recent study of nuclear workers in the USA and the International Nuclear Workers Study (INWORKS), concerning the difference in solid cancer risk estimates between those first hired in earlier and later calendar years, subsidiary analyses were conducted on a cohort of 172 452 workers in the National Registry for Radiation Workers (NRRW) from the UK. A total of 18 310 incident first primary solid cancer cases were registered in the period from 1955 until 2011 in the NRRW cohort and workers accrued 5.25 million person-years of follow-up. Incidences rates of all solid cancers combined, lung cancer and solid cancer excluding lung cancer were examined in terms of external radiation doses in the full cohort and in a sub-cohort of workers who had no record of internal exposure monitoring and were defined by the periods of first hire before and after the beginning of the years 1960, 1965 and 1970. All analyses were carried out using Poisson Regression. These analyses demonstrated that only for lung cancer between the pre-1965 and post-1964 periods is there strong evidence for a difference in the risks using the NRRW full cohort. In the other calendar period breakdowns and for the other cancer groups, there is no clear evidence of differences in the risks. The NRRW estimation of risks between recent and early workers is not generally consistent with the US workers cohort or the INWORKS evaluations that later hired workers are at much higher solid cancer risk than earlier hired workers, although INWORKS contains a significant part of the latest updated NRRW cohort as well as the US data. The conclusion that the INWORKS and US study data demonstrate a real difference in excess solid cancer risk from external radiation exposure between earlier and later workers is premature. The results presented here should also be treated with caution because of the limited corroborating evidence from other published studies. Information on internal doses, neutron doses as well as non-radiation factors such as smoking and asbestos exposure would be needed to make definitive inferences.
Joint operational situation assessment and firepower allocation method based on enhanced potential energy model
Authors: Xu Yitai , Yuan Jianbo , Zhou Wen , Yu Miao
Published: May 2024

The assessment of battlefield situations and the allocation of firepower are pivotal prerequisites for conducting joint operational planning. In response to the challenges posed by multi-service joint operations, this paper presents a methodology based on enhanced operational potential energy model for the assessment of battlefield situations and the generation of optimal firepower allocation plan. We focuses on the three-fold factors influencing operational effectiveness: spatial, informational, and environmental factors, and completes the enhanced operational potential energy model by integrating the assessment of joint operational situations and the generation of optimal firepower allocation plans. Finally, the effectiveness of this methodology is demonstrated through operational simulations in a joint anti-ship combat scenario.
Multi-scale quaternion CNN and BiGRU with cross self-attention feature fusion for fault diagnosis of bearing
Authors: Liu Huanbai , Zhang Fanlong , Tan Yin , Huang Lian , Li Yan , Huang Guoheng , Luo Shenghong , Zeng An
Published: May 2024

In recent years, deep learning has led to significant advances in bearing fault diagnosis (FD). Most techniques aim to achieve greater accuracy. However, they are sensitive to noise and lack robustness, resulting in insufficient domain adaptation and anti-noise ability. The comparison of studies reveals that giving equal attention to all features does not differentiate their significance. In this work, we propose a novel FD model by integrating multi-scale quaternion convolutional neural network (MQCNN), bidirectional gated recurrent unit (BiGRU), and cross self-attention feature fusion (CSAFF). We have developed innovative designs in two modules, namely MQCNN and CSAFF. Firstly, MQCNN applies quaternion convolution to multi-scale architecture for the first time, aiming to extract the rich hidden features of the original signal from multiple scales. Then, the extracted multi-scale information is input into CSAFF for feature fusion, where CSAFF innovatively incorporates cross self-attention mechanism to enhance discriminative interaction representation within features. Finally, BiGRU captures temporal dependencies while a softmax layer is employed for fault classification, achieving accurate FD. To assess the efficacy of our approach, we experiment on three public datasets (CWRU, MFPT, and Ottawa) and compare it with other excellent methods. The results confirm its state-of-the-art, which the average accuracies can achieve up to 99.99%, 100%, and 99.21% on CWRU, MFPT, and Ottawa datasets. Moreover, we perform practical tests and ablation experiments to validate the efficacy and robustness of the proposed approach. Code is available at https://github.com/mubai011/MQCCAF.
Accurate distances measures and machine learning of the texture-property relation for crystallographic textures represented by one-point statistics
Authors: Iraki Tarek , Morand Lukas , Link Norbert , Sandfeld Stefan , Helm Dirk
Published: May 2024

The crystallographic texture of metallic materials is a key microstructural feature that is responsible for the anisotropic behavior, e.g. important in forming operations. In materials science, crystallographic texture is commonly described by the orientation distribution function, which is defined as the probability density function of the orientations of the monocrystal grains conforming a polycrystalline material. For representing the orientation distribution function, there are several approaches such as using generalized spherical harmonics, orientation histograms, and pole figure images. Measuring distances between crystallographic textures is essential for any task that requires assessing texture similarities, e.g. to guide forming processes. Therefore, we introduce novel distance measures based on (i) the Earth Movers Distance that takes into account local distance information encoded in histogram-based texture representations and (ii) a distance measure based on pole figure images. For this purpose, we evaluate and compare existing distance measures for selected use-cases. The present study gives insights into advantages and drawbacks of using certain texture representations and distance measures with emphasis on applications in materials design and optimal process control.
Plant-mediated synthesis of Mn3O4 nanoparticles: challenges and applications
Authors: Zaragosa Gelo P , Ilem Carlo Nonato D , Conde Blessed Isaac C , Garcia Joel
Published: May 2024

This review focuses on the green synthesis methods, challenges, and applications of manganese oxide (Mn3O4) nanoparticles investigated in the past five years. Mn3O4 nanoparticles offer some unique properties that are attributed in part to the presence of mixed oxidation states of manganese (i.e. +2 and +3) in the particle, which can be utilized in a wide range of redox-sensitive applications, such as in developing supercapacitive energy storage materials. In addition, the green synthesis of Mn3O4 nanoparticles through plant extracts has potential uses in sustainable nanotechnology. Various plant extract-mediated synthesis techniques for Mn3O4 nanoparticles have been investigated and presented. By comparing the size and structure of the synthesized Mn3O4 nanoparticles, we have observed a consistent pattern of obtaining spherical particles with a size ranging from 16 to 50 nm. The morphology of the generated Mn3O4 nanoparticles can be influenced by the annealing temperature and the composition of the plant extract used during the nanoparticle synthesis. Additionally, numerous applications for the greenly produced Mn3O4 nanoparticles have been demonstrated. Mn3O4 nanoparticles derived from plant extracts have been found to possess antimicrobial properties, supercapacitive and electrochemical capabilities, and excellent pollutant degradation efficiency. However, the magnetic properties of these nanoparticles synthesized by plant extracts are yet to be explored for potential biomedical applications. Finally, challenges to existing synthetic methods and future perspectives on the potential applications of these green synthesized Mn3O4 nanoparticles are highlighted.
Development of IPMC actuators with high bending uniformity and orientation
Authors: Lin Faming , Xu Haidong , Wang Tao , Wen Yalian , Liu Yifan
Published: May 2024

Ionic polymer-metal composite (IPMC) actuators have attracted considerable scientific interest in the field of robotics and artificial muscles due to their low operating voltage, high strain capacity, and lightweight. However, the non-uniform bending of IPMC actuators affects their control accuracy and limits their potential applications. In this work, the surface voltage of IPMC actuators was measured and the internal electric field distribution was numerically computed. It was concluded that the non-uniform bending is mainly due to the non-uniform distribution of hydrated cations inside the IPMC as a result of the inhomogeneous electric field. The bending uniformity is improved by sputtering a gold layer on the surface of the IPMC actuator, and a support strip is introduced to limit the bending of the IPMC in the width direction, resulting in an improvement of its pointing characteristics. It is found that the bending uniformity of IPMC improved by 35.27% and 119.48% by sputtering at an input voltage of 2.5 V and 5 V respectively. When the input voltage is fixed at 2.5 V and 5 V, the bending in the width direction is reduced by 75.68% and 93.12% with the support structure, respectively.
High performance H2 sensors based on NiO-SnO2 nanosheets in temperature-pulsed operation mode
Authors: Li Mingjie , Luo Wenxin , Yan Wenjun
Published: May 2024

Enhancements in the responses of semiconductor gas sensors for hydrogen (H2) are imperative to ensure the safety for industrial processes and fuel cells applications. Alternative to the conventional method of maintaining an optimum isothermal temperature, this study presents a novel technique that sequentially modulates the physisorption and chemisorption processes of the target gas and oxygen species through a temperature-pulsed strategy. This method substantially amplified the electrical responses of a NiO-doped SnO2 gas sensor to H2 vapor. Under the optimum pulsed-heating condition, the sensor achieved a remarkable response of 252–300 ppm H2, which is comparable to or better than that of many existing H2 sensors. The integration of a pulse-driven microheater with a heterojunction-forming sensing layer has led to improved sensitivity, providing additional opportunities for H2 monitoring.
Dynamic analysis of the three-phase magneto-electro-elastic (MEE) structures with the finite element method enriched by proper enrichment functions
Authors: Chai Yingbin , Huang Kangye , Wang Shangpan , Zhang Qifan
Published: May 2024

In this study, a carefully designed enriched finite element method (EFEM) is presented to improve the solution accuracy of the conventional FEM by analyzing the dynamic behavior of the magnetic-electric-elastic (MEE) composite structures, which are frequently used in designing various smart and intelligent devices. By formulating the proper EFEM with ideal numerical performance, different enrichment functions are considered and the corresponding solution quality of different versions of the EFEM is compared and examined in great detail. When the Lagrange polynomial basis functions together with the harmonic trigonometric functions are used as enrichment functions, the obtained EFEM shows extremely powerful and ideal numerical performance, which is obviously better than the other versions of EFEM and the conventional FEM, in studying the free vibration and harmonic frequency responses of the MEE structures. Nearly exact numerical solutions for three-phase physical fields of MEE structures can be generated by the proposed EFEM even if very coarse mesh patterns are used. Intensive numerical studies are conducted to confirm and verify the excellent properties of the proposed EFEM in performing dynamic analysis of the MEE structures.
Magnetic dipole transition in proton-deuteron radiative capture at BBN energies within potential model
Authors: Le Anh Nguyen , Nhut Anh Dao , Huy Tho Do , Huu Nha Nguyen
Published: May 2024

The pd radiative capture reaction plays a vital role in Big Bang nucleosynthesis and stellar proton-proton chain. The study of the low-energy reaction is challenging in both experiments and theories. Using the framework of potential model, we analyze pd radiative capture below 1 MeV for both electric dipole (E1) and magnetic dipole (M1) transitions. The obtained astrophysical S factors agree well with recent results, especially at energies relevant to sensitive deuterium abundance. The calculated reaction rate shows good agreement, with less than a 5% difference compared to recent works. The extrapolated value for S(0) including both transitions is determined to be 0.211 ± 0.016 eV b. A comparison with experimental data using the χ
2 test reveals the sensitivity of the M1 cross section at low energies to the scattering potential depth.
Ultraviolet-visible spectroscopy with all-dielectric multi-foci dispersive metalens
Authors: Butt Naureen , Mahmood Nasir , Tauqeer Tauseef , Cabera Humberto , Khan Muhammad Faisal , Zubair Muhammad , Massoud Yehia , Mehmood Muhammad Qasim
Published: May 2024

Metasurfaces are a cutting-edge development in optical technology miniaturization, enabling the manipulation of light at a microscopic scale while providing unprecedented control over its intrinsic characteristics, such as amplitude, polarization, and phase. Researchers have been making significant progress in advancing and developing high-efficiency and functionally versatile metasurfaces, aiming to achieve miniaturization and overcoming the technological limitations of conventional components. This article is intended to develop a single-layered, highly transmissive all-dielectric multi-foci metalens that serves as a compact spectrometer for portable investigative measurements within the ultraviolet to the visible spectrum, especially for

290
–
460

nm

band. The proposed metalens can achieve top-notch performance by precisely mapping the wavelength information into subwavelength diffraction-limited focusing spots. This approach helps in accomplishing simultaneous spectral splitting and focusing on the same plane. The proposed metalens consists of an array of intelligently optimized nanoantennas made of a CMOS-compatible silicon nitride material. It exploits a unique phase and wavelength multiplexing strategy to create highly dispersive multi-foci metalens, making it an ideal choice for an ultra-compact, high-resolution, and dual-band meta-spectrometer. We expect our proposed framework to have numerous applications in the industrial and medical fields, enabling diagnosis, detection, and assessment within a compact platform.
Atmospheric Parameters and Abundances of Cool Red Giant Stars
Authors: Dencs Z. , Derekas A. , Mitnyan T. , Andersen M. F. , Cseh B. , Grundahl F. , Hegedűs V. , Kovács J. , Kriskovics L. , Palle P. L. , Pál A. , Szigeti L. , Mészáros Sz.
Published: May 2024

Understanding the atmospheric parameters of stars on the top of the RGB is essential to reveal the chemical composition of the Milky Way, as they can be used to probe the farthest parts of our Galaxy. Our goal is to determine the chemical composition of 21 RGB stars with T
eff < 4200 K selected from the APOGEE-2 DR17 database using new observations carried out with the spectrograph mounted on the 1 m telescope of the Hungarian Piszkéstető Observatory and the SONG spectrograph (R = 77,000) on the Hertzsprung SONG telescope in the 4500–5800 Å wavelength range. This is the first time the spectrograph (R = 18,000) on the 1 m telescope at Piszkéstető Observatory was used to measure the abundances of stars. We created a new LTE spectral library using MARCS model atmospheres and SYNSPEC by including the line list of 23 molecules to determine atmospheric parameters (T
eff,

log
g

, [Fe/H], [α/Fe]) and abundances of Si, Ca, Ti, V, Cr, Mn, and Ni with FERRE. The resulting parameters were compared to that of APOGEE. We found a good agreement in general, the average difference is −11.2 K in T
eff, 0.11 dex in

log
g

, 0.10 dex in [Fe/H], and −0.01 dex in [α/Fe]. Our analysis successfully demonstrates the ability of the spectrograph at Piszkéstető Observatory to reliably measure the abundance of bright stars.
Development of a neural network model for peeling–ballooning stability analysis in the KSTAR tokamak pedestals
Authors: Heo C. , Kim B. , Kwon O. , Kim S.K. , Na Y.-S.
Published: May 2024

The neural network model, MISHKA-NN is developed to mitigate the computational burden associated with the linear ideal magnetohydrodynamic (MHD) stability analysis of the pedestal based on the peeling–ballooning (P–B) model. By utilizing both 1D plasma profiles (current density, pressure gradient, and safety factor) and 0D parameters (plasma geometry, total current, and toroidal mode number), the model predicts linear growth rate of edge-localized ideal MHD instability in a given equilibrium state. By enabling the prediction of each instability within a second, the model reduces the time required for plotting a pedestal P–B stability diagram (

j
−
α

diagram) from approximately 100 CPU hours to a few CPU minutes. Notably, even with the utilization of parametric pressure and current profiles and plasma boundary shapes for the training dataset, the model shows a satisfactory level of performance in benchmarking the

j
−
α

diagram for the reconstructed equilibrium from a KSTAR tokamak experiment. We anticipate the model to serve as a versatile alternative to 2D linear MHD stability codes, alleviating numerical costs.
Fast ion relaxation in ITER mediated by Alfvén instabilities
Authors: Gorelenkov N.N. , Duarte V.N. , Gorelenkova M.V. , Lin Zh. , Pinches S.D.
Published: May 2024

We address the critical issue for future burning plasmas of whether high-energy fusion products or auxiliary heating-beam ions will be confined for a sufficiently long time to compensate for thermal plasma energy losses. This issue can be mitigated by one of the most deleterious collective phenomena—the instability of low, sub-cyclotron frequency Alfvén eigenmodes (AEs), such as toroidicity-induced AEs and reversed-shear AEs in the ITER steady-state scenario. Using a revised quasi-linear (QL) theory applied to energetic particle (EP) relaxation in the presence of AEs, we find that the AE instabilities can affect both neutral beam ions and alpha particles, although the resulting fast ion transport is expected to be modest if classical particle slowing down is assumed. On the other hand, the QL theory predicts that the AE amplitudes will be enhanced by the background microturbulence, although this topic remains outside our scope due to the significant numerical effort required to evaluate these effects. We report our results for EP relaxation dynamics obtained utilizing several tools: (i) a comprehensive linear stability study of the sub-cyclotron Alfvénic spectrum as computed by ideal magnetohydrodynamic NOVA simulations for the AE eigenproblem, (ii) drift kinetic NOVA-C calculations for wave–particle interaction and AE growth/damping rates, and (iii) predictive QL modeling coupled with the global transport code TRANSP to assess the EP relaxation on the equilibrium timescale.
Interactions between different birds of prey as a random point process
Authors: Akemann Gernot , Chakarov Nayden , Krüger Oliver , Mielke Adam , Ottensmann Meinolf , Pässler Patricia
Published: May 2024

The two-dimensional (2D) Coulomb gas is a one-parameter family of random point processes, depending on the inverse temperature β. Based on previous work, it is proposed as a simple statistical measure to quantify the intra- and interspecies repulsion among three different highly territorial birds of prey. Using data from the area of the Teutoburger Wald over 20 years, we fit the nearest-neighbour and next-to-nearest neighbour spacing distributions between the respective nests of the goshawk, eagle owl and the previously examined common buzzard to β of the Coulomb gas. Within each species, the repulsion measured in this way deviates significantly from the Poisson process of independent points in the plane. In contrast, the repulsion amongst each of two species is found to be considerably lower and closer to Poisson. Methodologically, we investigate the influence of the terrain, of a shorter interaction range given by the 2D Yukawa interaction, and the statistical independence of the time moving average we use for the yearly ensembles of occupied nests. We also check that an artificial random displacement of the original nest positions of the order of the mean level spacing quickly destroys the repulsion measured by β > 0. A simple, approximate analytical expression for the nearest-neighbour spacing distribution derived from non-Hermitian random matrix theory proves to be very useful.