bluuebunny/crossref_metadata_2025 huggingface dataset:
Lumbar Discal Cyst: Is it a Rare Consequence in Lumbar Disc Disease Spectrum? Short Case Series with Review of Literature and Hypothesis Regarding Etiopathogenesis
Authors: Pai Usha Kota Narayana , Sathyanarayanan Devaprasad , Haridas Harsha Manjarambath
Published: June 2023

Background Lumbar discal cysts are rare intraspinal extradural lesions presenting as lumbar radiculopathy. The rarity of the lesion is sufficient to evoke interest in its diagnosis. The hitherto unsolved etiopathogenesis prompted us to look into these areas in this study.

Objectives 1) To review the literature and summarize the clinicoradiological and histopathological features of the discal cyst. 2) To investigate possible mechanisms in the etiopathogenesis of discal cysts.

Materials and Methods Three patients presented with features suggestive of lumbar disc prolapse and were diagnosed with discal cyst over 1.5 years and were included in this study. All patients underwent lumbar spine magnetic resonance imaging (MRI) and were subsequently treated by cyst excision. The final diagnosis of the discal cyst was based on histopathological features.

Results Out of three patients, two had a discal cyst with disc prolapse, and one had a discal cyst alone. Discal cyst patient underwent excision of cyst alone. Discal cyst patients with disc prolapse underwent discectomy in addition to excision of the discal cyst. One patient had an L2–L3 level discal cyst with disc prolapse, which is uncommon.

Conclusions Lumbar discal cysts, although rare, form an important differential diagnosis in patients with lumbar radiculopathy. They have a distinctive MRI appearance, and because discal cyst and disc prolapse shared similar etiopathological features, we hypothesize that discal cyst is a part of the degenerative disc disease spectrum. We also conclude that discal cyst excision should be coupled with discectomy when LDC is associated with disc prolapse.
Application of Magnesium Oxide Nanoparticles in Dentistry: A Literature Review
Authors: Sharifian Seyedarsham , Loghmani Alireza , Nayyerain Shiva , Javanbakht Sanaz , Daneii Pouria
Published: June 2023

Magnesium oxide (MgO) nanoparticles' biocompatibility and degraded by-products are the two most important factors that make this material preferable in dental care. Their specific characteristics, such as antibacterial action against cariogenic microbes, are potential antibacterial agents for dental applications. This paper investigates the properties of MgO in dentistry and sets the groundwork for future research. Electronic databases, including PubMed/Medline, Scopus, Google Scholar, and scientific-research journals of domestic universities were reviewed from 1972 to 2022, and all the relevant papers were surveyed. After a search in electronic databases, 60 articles were involved, and the needed details were extracted. The biochemical features and application of magnesium oxide nanoparticles (MgONPs) in dentistry and new fields have been discussed in detail. Nanoparticles (NPs) may provide a unique method for treating and preventing dental infections. MgO nanoparticles are a good choice in several fields because their unique properties, such as antibacterial activity against cariogenic microorganisms, make them ideal antibacterial agents for dental applications.
Step Ladder Expansive Cranioplasty: A Novel Perspective in Cranial Volume Augmentation Surgery
Authors: Sengupta Sudip Kumar , Sundervadhanan Shashivadhanan , Rappai Tony J. , Sudumbrekar S.M. , Gorthi Sankar Prasad , Verma Saurabh K.
Published: June 2023

Background In face of a refractory raised intracranial pressure (ICP), surgeons most commonly resort to decompressive craniectomy (DC). Procedure leaves an unprotected brain underlying the craniectomy defect and Monro-Kellie doctrine: disrupted. Different variants of hinge craniotomies (HC) have been used with clinical outcomes comparable to DC as single stage alternatives. However, both DC and every variant of HC have a limit to the achievable volume augmentation and all invariably cause a compression of the cerebral cortex and its vasculature at the craniotomy site. We believe both these limitations adversely affect the outcome.

Methods A team of neuroscientists in Indian Armed Forces Medical Services has been working for the last 9 years toward developing a novel surgical technique that can mitigate both these drawbacks. Desired procedure should take the centripetal pressure exerted by the combination of the tensile strength of the scalp (with or, without an underlying bone flap) and atmospheric pressure off the brain surface while achieving an assured augmentation of intracranial volume that can be optimized on a case-to-case basis. We call it a “step ladder expansive cranioplasty.”

Results The distance of the parietal eminence was found to have increased by 10.2 mm on the operated side after expansive cranioplasty.

Conclusion From drawing board to bedside, we have made some progress toward our goal, but it is still far away from completion. More studies are required to fill in the gaps in our knowledge necessary to optimize the various parameters of the surgery. Procedure has promise to be of special role in in war and disaster scenarios.
Anemia Prevalence, Characteristics, and Hematological Profile among Stunted Children Under 2 Years Old in Bandung Regency, Indonesia
Authors: Purnami Grace Mediana , Praba Kania Dyatika , Fauziah Iif Latifah , Dewi Mia Milanti , Judistiani Raden Tina Dewi , Setiabudiawan Budi
Published: June 2023

Anemia and stunted growth are major health problems with adverse consequences for children. This study aimed to determine the prevalence, characteristics, and hematological profile of anemia among stunted children under 2 years old. A nested cross-sectional study from a child cohort was conducted in Bandung Regency, West Java, Indonesia. Two hundred twenty-two children aged 6 to 24 months were randomly selected. These children were reexamined from November 2019 to March 2020 for anthropometric measurements and hematological assessment and interviewed for relevant risk factors of stunted growth and anemia. Ninety-eight stunted children were identified and distributed into stunted and severely stunted groups (47.96 vs. 52.04%). Around 85.4% of the children came from low-income families and 31.7% were severely underweight for age. Surprisingly most of these stunted children had normal birth weight and length and were born at term (68.3, 53.7, and 85.4%). The prevalence rate of anemia among stunted children was 41.8%, they had decreased mean corpuscular volume (56%), decreased mean corpuscular hemoglobin (73%), and normochromic mean corpuscular hemoglobin concentrations (51.2%). Leucocytosis was higher than leucopenia (10 vs. 3.7%) and thrombocytosis (n = 15, 36%) as compared to thrombocytopenia (n = 5, 12%). The prevalence of anemia was high among stunted children. The characteristics of stunted children with and without anemia were similar. The fact that these stunted children had few risk factors for stunting emphasizes the need to focus on improved postnatal care to prevent faltering. Based on the hematology profile, iron deficiency anemia was suspected to be the most etiology in these cases warranting further follow-up and management.
Effect of Determinants of Health on the Hearing Care Framework: An Economic Perspective
Authors: Amlani Amyn M.
Published: June 2023

Hearing care is expanding accessibility to consumers through new service delivery channels and methods of technology distribution (see Brice et al, this issue). This diversification has the potential to overcome longstanding consumer disparities (e.g., health, socioeconomic, psychological, environmental) in receiving care and provider constraints (e.g., accessibility, geography, direct access) to delivering care that adversely impacts quality of life (e.g., social isolation, depression, anxiety, self-esteem). In this article, the reader is provided with an overview of health outcomes factors (i.e., determinants of health)—in the context of an economic framework (i.e., supply, demand)—and their effect on consumer behavior and provider preferences toward hearing healthcare services. This overview also affords readers with strategic business insights to assess and integrate future hearing care services and technology to consumers in their local markets.
Barriers to Adoption of Digital Therapeutics (DTx) into Audiology Clinical Practice: Acknowledging the Challenges, Adapting to the Future
Authors: Roberts Melissa J. , Wilson Wayne J. , Recugnat Matthieu , Bardy Fabrice
Published: June 2023

The continuous advancements in technologies supporting digital health and digital therapeutics (DTx) bring new possibilities to the field of audiology. This study considers a new DTx for tinnitus called Tinnibot and the willingness of a group of Australian university audiology students to consider this new DTx in their future careers as practicing audiologists. A single-group case-series design (pretest/posttest) was used to examine the opinions of 10 university audiology students before and after participating in a 2-hour information workshop on the topics of tinnitus, DTx, cognitive behavioral therapy, and a new digital therapy tool for tinnitus called Tinnibot. Student knowledge levels of the main topic areas increased from poor (before the workshop) to moderate to high after the workshop, with 40% of participants reporting they would very likely use digital therapies for future patients. A common barrier to improving this rating was the need for direct hands-on training on the DTx before the students would be confident to recommend the DTx to patients. Incorporating direct training on DTx into university audiology programs would allow greater uptake of DTx by students as they begin their careers as practicing audiologists.
Exploring Hearing Care Technology from Clinic to Capability
Authors: Penno Kathryn A. , Zakis Justin A.
Published: June 2023

Healthcare systems are traditionally a clinician-led and reactive structure that does not promote clients managing their health issues or concerns from an early stage. However, when clients are proactive in starting their healthcare earlier than later, they can achieve better outcomes and quality of life. Hearing healthcare and the rehabilitation journey currently fit into this reactive and traditional model of care. With the development of service delivery models evolving to offer services to the consumer online and where they are predominately getting their healthcare information from the internet and the advancement of digital applications and hearing devices beyond traditional hearing aid structures, we are seeing a change in how consumers engage in hearing care. Similarly, as the range of hearing devices evolves with increasingly blended and standard levels of technology across consumer earbuds/headphones and medical grade hearing aids, we are seeing a convergence of consumers engaging earlier and becoming increasingly aware of hearing health needs. This article will discuss how the channels, service, and technology are coming together to reform traditionally clinician-led healthcare models to an earlier consumer-led model and the benefits and limitations associated with it. Additionally, we look to explore advances in hearing technologies and services, and if these will or can contribute to a behavioral change in the hearing healthcare journey of consumers.
Analysis of Factors Contributing to Antenatal Corticosteroid Administration in Patients Presenting with Threatened Preterm Labor
Authors: Bode Leah , McKinzie Alexandra H. , Gidia Nadia M. , Ibrahim Sherrine A. , Haas David M.
Published: June 2023

Objective This study aimed to analyze characteristics of those seen for threatened preterm labor (tPTL) who receive antenatal corticosteroids (ACS) to better understand clinical decision-making.

Study Design This retrospective cohort study consisted of patients seen in triage at an urban county hospital in 2021 for tPTL during pregnancy. Demographic variables (maternal age, race/ethnicity, and prior preterm delivery) and obstetrical variables (cervical dilation, effacement, membrane rupture, and tocolytic administration) were evaluated against the primary outcome of ACS administration.

Results After exclusions, a cohort of 290 pregnant people with 372 unique encounters for tPTL remained. The mean maternal age was 26.7, and 15.6% of patients had a history of prior preterm birth. A total of 107 patients in 111 encounters received ACS, which were associated with lower body mass index (BMI), greater cervical dilation, greater effacement, membrane rupture, and more frequent contractions (all ps < 0.01). The mean presentation was at 33.5 weeks. Only 44% of those receiving ACS delivered within 7 days, compared with 11% of those who did not receive ACS (p < 0.001). Half (50%) of the patients receiving ACS delivered at >37 weeks. Adjusting for significant factors in the univariable analysis and limited to first encounter in triage, BMI (odds ratio: 0.91, 95% confidence interval: 0.87–0.95), cervical dilation ≥ 2 cm (2.49, 1.12–5.35), and cervical effacement ≥ 50% (4.80, 2.25–10.24) were significantly associated with patients receiving ACS.

Conclusion Greater cervical dilation and effacement and a lower BMI were associated with ACS administration, although most patients receiving ACS still did not deliver within 7 days.

Key Points
Firm value in the airline industry: perspectives on the impact of sustainability and Covid-19
Authors: Abdi Yaghoub , Li Xiaoni , Càmara-Turull Xavier
Published: June 2023

To date, there has been limited research undertaken into firm value determinants in the air transport industry, one of the most essential sectors for global business. In view of this, in this study, we review and synthesise the literature that focuses on the value of firms in this sector and discuss conceptually and empirically the determinants influencing airlines’ stock values. Our main objective is to widen our understanding of the current state of research on the firm value of air transport companies. Using the systematic literature review (SLR) approach, we classify 173 papers published from 1984 to 2021. We find considerable changes in academic interest in the topic over the time period analysed, especially as a consequence of crisis-induced market crashes. In addition, we classify the main research themes relating to airlines’ market value, identify gaps, and introduce potential future research avenues in this area. Among the themes identified, the adjustment in the industry-level factors such as alliances, market structure and competition were the most common source of fluctuations in airlines’ stock value. However, we find shifting to sustainability initiatives and its consequence for stakeholders’ value as one of the most discussed topics in this context. The trend has gained attention since early 2020 due to the emergence of the Covid-19 pandemic as companies are looking for green and sustainable ways to protect the value in crisis time. Our findings assist transportation researchers and executives in addressing major value drivers of airline firms.
Why do adults seek treatment for gaming (disorder)? A qualitative study
Authors: Karhulahti Veli-Matti , Behm Sanni , Lukka Lauri
Published: June 2023

Despite gaming disorder now being diagnosable by the International Classification of Diseases (ICD-11) as a new mental disorder due to addictive behaviors, little is known about the concrete reasons for which people seek treatment for their videogame play. As the current literature is mainly based on children and adolescents, there is a strong need for better understanding adult treatment-seekers in particular. This preregistered study responds to the gap in research by qualitatively investigating the reasons for treatment-seeking with 110 participants who had sought help for their videogame play from a Finnish treatment program. We applied template analysis to the open-ended data, which consist of the participants’ personal accounts regarding their problems. Additionally, we report the game titles that the participants had problems with, as well as Internet Gaming Disorder Test (IGDT-10) scores, which were measured from 89 participants. The template analysis suggested five themes, which cover the main reasons for treatment-seeking: social reasons, existential reasons, practical reasons, self-perceived addiction, and wish for support. Many of these themes overlap with the ICD-11 description of gaming disorder, but several issues, such as loss of meaning and financial harms, are not part of the current diagnosis. The average IGDT-10 score among participants was 3.86 (SD = 2.55) and 37 (42%) individuals met the disorder cutoff (5.00). Numerous videogames with different designs were mentioned as sources of problems, of which 26 were mentioned more than once. The study indicates that adults seek treatment for many kinds of games and gaming-related problems, including but not limited to those, which are described part of the ICD-11 gaming disorder diagnoses. We recommend both researchers and practitioners to implement an expanded perspective on gaming behaviors, acknowledging that adults may seek treatment for diverse gaming-related problems, some of which not necessarily relevant to gaming disorder or mental disorders in general.
Valuation of candidate brand equity dimensions and voting intention: alternative polling data in the Spanish presidential election
Authors: Gutiérrez-Rodríguez Pablo , Villarreal Ricardo , Cuesta-Valiño Pedro , Blozis Shelley A.
Published: June 2023

The current research examines the options available for political candidates to leverage their brand in order to influence voting intentions. Candidates, owing to the strong psychological connections they establish with their voters, are well-positioned to construct brand equity. Emotions are part of any brand–consumer relationship, but in the case of politics, the importance of this dimension may be more significant given that the brand, in this case, is a living person. This is expressed in the degree of consumer–voter commitment and emotional involvement. A multidimensional construct of brand equity is used to explore the relationships between its dimensions and voter intentions. The findings suggest a robust correlation between candidates’ brand equity and respondents’ future voting intentions. In addition, it is feasible to ascertain the characteristics of the brand equity of the different candidates and to identify the dimensions on which to focus efforts to improve brand equity. The current study enhances the utilization of candidate brand equity assessment as a viable alternative to polling data in practice. Its contribution lies in the potential to effectively manage the various dimensions of brand equity for the benefit of a candidate.
Understanding the mediating effect of switching costs on service value, quality, satisfaction, and loyalty
Authors: Ha Minh-Tri , Nguyen Giang-Do , Doan Bao-Son
Published: June 2023

This work examines the connections between service quality (SQ), service value (SV), customer satisfaction (CS), and customer loyalty (CL) within the healthcare industry. In addition, we seek to provide empirical evidence regarding the impact of different types of switching barriers, including procedural, financial, and relational costs, on these relationships. This is because switching costs are the key factors for maintaining and developing the relationship with the customer. The paper uses the Partial Least Squares Structural Equation Modeling (PLS-SEM) method for assessing the structure of - and examining - the valid data sample of 300 people, who have all experienced service from private healthcare in Ho Chi Minh City (HCMC), Vietnam. This paper is the first to study the three-dimensional switching costs (SC) (procedural, financial, and relational) as mediators of the CS-CL, and SV-CL relationships together in the private healthcare sector. The significant contributions of this paper include: (1) procedural, financial, and relational switching costs which have a determinant impact on customer loyalty (CL). Moreover, loyalty is also achieved through value given, and the pleasure of clients in the healthcare sector, (2) while customer satisfaction (CS) is a mediator of service value (SV) and CL, SV intervenes between the SQ and CS, (3) procedural/financial switching costs partially mediate the effects of the SV, CS, and CL relationships. Both academic contributions and managerial recommendations are provided by the results of this research in order to enrich the literature, and also to suggest that companies build stronger relationships with their customers and thus retain them.
The worldview and interculturality in the training of entrepreneurs: a model of participatory edu-communication in Ecuador
Authors: Ruiz Chagna Claudia A. , Iglesias Rodríguez Ana
Published: June 2023

The education system in Ecuador has historically been structured in a way that excludes women, especially those living in the urban-marginal and rural sectors, where access and permanence are hindered by socio-economic and cultural factors. The objective of the study is the design of an Intercultural Edu-communication Model for the Training of Women Entrepreneurs (MEIFE), which recognizes and legitimizes intersectionality, Interculturality and the gender approach, as a sustainable path towards Good Living or “sumak kawsay”. The methodology used is based on participatory research that includes a qualitative-quantitative method, in which direct observation, interviews and surveys were used as techniques. The design was elaborated considering sources of indigenous, Afro-Ecuadorian and mestizo thought. The study shows that the education system for women in Imbabura widens the gap in the rural sector: only 33% of the women surveyed have completed six years of basic education, and 15%, although they passed one or more courses, did not finish. Regarding secondary education, 14% of women have completed all years of secondary education, and 17.85% have attended one year of study. Seven per cent of the women surveyed had not attended formal education. In response, MEIFE is a non-formal education tool aimed at women entrepreneurs, developed taking into account the indigenous worldview, who form part of a community where it is necessary to create opportunities and encourage initiatives that allow them to generate income and guarantee their autonomy in coherence with their ancestral culture.
Transferring graph neural network models for predicting bond dissociation energy between datasets
Authors: Huo Yao-Yuan , Jiang Jun
Published: June 2023

Machine learning (ML) approaches like neural networks have been widely used in chemical researches for fast estimating chemical properties. Generating ML models of good precision requires datasets of high quality, which can be difficult to obtain. In this work, we trained graph neural network (GNN) models from different datasets and verified transferring of the models to other datasets. Our result shows that crossdataset evaluation can give less accurate but still correlative prediction results on different datasets. Errors are mainly due to systematic errors. The value range of prediction result is highly related to the range of training set. The precisions of different bonds show different distributions. C–H bond constantly gets the highest precision in the tested bonds.
Development and characterization of a narrow-pulsed molecular beam system
Authors: Xie Yurun , Liu Heyang , Xiao Yue , Han Jie , Li Zhichao , Wang Yuzhao , Wang Tao , Yang Xueming , Yang Tiangang
Published: June 2023

A narrow-pulsed and velocity-controlled molecular beam system is constructed by using a high-speed chopper and a temperature adjustable pulsed valve. The duration of the hydrogen molecular beam pulse is reduced to approximately 6.3 µs and characterized using resonance-enhanced multiphoton ionization (REMPI) at a distance of ~193 mm downstream from the nozzle. To precisely determine the velocity of the hydrogen molecules, a pump-probe technique combining stimulated Raman pumping and REMPI is employed at a fixed distance (193 mm) with nanosecond lasers. By adjusting the temperature of the pulsed valve, the velocity of the hydrogen beam varies continuously from 1290 m/s to 3550 m/s. The system exhibits potential for multiple applications in the field of chemical reaction dynamics, including its potential to integrate with ion traps and surface scattering experiments.
Simulation of dynamic monitoring for intracerebral hemorrhage based on magnetic induction phase shift technology
Authors: Chen Ruijuan , Li Dandan , Zhao Songsong , Zhang Yuanxin , Wang Huiquan , Wu Yifan
Published: June 2023

Intracerebral hemorrhage (ICH) is a common and severe brain disease associated with high mortality and morbidity. Accurate measurement of the ICH area is an essential indicator for doctors to determine whether a surgical operation is necessary. However, although currently used clinical detection methods, such as computed tomography (CT) and magnetic resonance imaging (MRI), provide high-quality images, they may have limitations such as high costs, large equipment size, and radiation exposure to the human body in the case of CT. It makes long-term bedside monitoring infeasible. This paper presents a dynamic monitoring method for ICH areas based on magnetic induction. This study investigates the influence of the bleeding area and the position of ICH on the phase difference at the detection point near the area to be measured. The study applies a neural network algorithm to predict the bleeding area using the phase difference data received by the detection coil as the network input and the bleeding area as the network output. The relative error between the predicted and actual values of the neural network is calculated, and the error of each group of data is less than 4%, which confirms the feasibility of this method for detecting and even trend monitoring of the ICH area.
Coupling multi-fidelity xRAGE with machine learning for graded inner shell design optimization in double shell capsules
Authors: Vazirani N. N. , Grosskopf M. J. , Stark D. J. , Bradley P. A. , Haines B. M. , Loomis E. N. , England S. L. , Scales W. A.
Published: June 2023

Bayesian optimization has shown promise for the design optimization of inertial confinement fusion targets. Specifically, in Vazirani et al. [Phys. Plasmas 28, 122709 (2021)], optimal designs for double shell capsules with graded inner shells were identified using one-dimensional xRAGE simulation yield calculations. While the machine learning models were able to accurately learn and predict one-dimensional simulation target performance, using simulations with higher fidelity would improve design optimization and better match with the expected experimental performance. However, higher fidelity physics modeling, i.e., two-dimensional xRAGE simulations, requires significantly larger computational time/cost, usually at least an order of magnitude, in comparison with one-dimensional simulations. This study presents a multi-fidelity Bayesian optimization, in which the machine learning model leverages low-fidelity (one-dimensional xRAGE) and high-fidelity (two-dimensional xRAGE) simulations to more accurately predict “pre-shot” target performance with respect to the expected experimental performance. By building a multi-fidelity Bayesian optimization framework coupled with xRAGE, the low-fidelity and high-fidelity simulations are able to inform one another, such that we have: (1) improved physics modeling in comparison with using low-fidelity simulations alone, (2) reduced computational time/cost in comparison with using high-fidelity simulations alone, and (3) more confidence in the expected performance of optimized targets during real-world experiments. In the future, we plan to use this robust multi-fidelity Bayesian optimization methodology to expedite the design of graded inner shells further and eventually full capsules as a part of the current double shell campaign at the National Ignition Facility.
Real-time anomaly data detection method based on mixed kernel function PSO-SVR
Authors: Wang Tong , Cao Xiliang , Li Yuhang , Zhai Yidi , Ye Guoyong
Published: June 2023

To avoid the influence of abnormal data of micro-plant factory sensors on the control system, an abnormal data detection method based on mixed kernel function particle swarm optimization (PSO)-support vector regression (SVR) is proposed. First, the mixed kernel function constructed by the polynomial kernel and radial basis kernel is used as the kernel function of SVR, and PSO is introduced to optimize the hyperparameters of the SVR model and establish a prediction model. Then, the model completes a step-by-step prediction based on the data in the sliding window and calculates confidence intervals. Finally, the data are judged to be abnormal based on whether the measured values exceed the confidence interval, and the abnormal values are replaced with the predicted values. The results show that the mean absolute percentage error of the model is 0.0063, the accuracy is 99.63%, the prediction accuracy and detection accuracy are better than the comparison model, and the abnormal data in the sensor data flow can be effectively detected and processed.
Surface engineering of metallic nanocrystals via atomic structure and composition control for boosting electrocatalysis
Authors: Whang Youngjoo , Kwon Yongmin , Ahn Hojin , Hong Jong Wook , Han Sang Woo
Published: June 2023

Since the clean energy industry emerged, developing efficient nanocrystal catalysts has attracted ever-increasing attention. Recently, the utilization of metal nanocrystals as catalysts for electrochemical reactions is entering a new era with the development of theories and techniques that help incorporate surface chemistry into nanoscale materials. Current approaches in the field of nanocrystal catalysts include detailed analyses and modifications of the surface atoms of nanocrystals, with which optimal structures and compositions for target electrochemical reactions could be realized. This review presents two major strategies to engineer the surface structure of nanocrystals: control over the atomic arrangement and composition of nanocrystal surfaces. The first section mainly covers the modification of surface atom arrangements with various methods, including the induction of various facets, strains, and defects. The generation of anomalous crystal structures of nanocrystals is also discussed. The second section encompasses recent advances in controlling the composition of nanocrystal surfaces by bringing high entropy or periodicity to the metal elements in nanocrystals to attain high electrocatalytic activity and stability.
Acoustic plate-valve resonator for low-frequency sound absorption
Authors: Hossain Md Robiul , Ross Eoghan P. , Bennett Gareth J.
Published: June 2023

An acoustic plate-valve resonator is developed and optimized to maximize absorption by enhancing the Helmholtz resonance with coincident structural vibrations of the plate-valve. The current research initially examines the concept experimentally with a 3D printed valve. Then with the use of analytical and numerical modeling, a structural analysis is performed, which allows the eigenmodes and eigenfrequencies of the plate-valve to be determined. When the resonator properties are modified by changing either the depth of the backing cavity or the thickness of the plate-valve, the system can be designed in such a way that the Helmholtz resonance can be coincident with a particular eigenfrequency, leading to absorption higher than that achieved in the absence of such a flexible plate-valve. In addition, absorption also occurs at frequencies other than the Helmholtz frequency due to the vibration of the plate at additional eigenfrequencies. Both of these aspects of the technology advance the state-of-the-art in Helmholtz resonator design. Good agreement has been found between the modeling and experimental results. Near-perfect absorption was achieved experimentally, e.g., up to α = 0.995 below 1 kHz; in addition, given that the thickness of the technology can be a very small percentage of the acoustic wavelength that it is absorbing, deep sub-wavelength ratio absorbers can be designed, e.g., a ratio of up to 58 was achieved in this study with a 5 mm deep technology at 1.18 kHz.
Exploring the water capture efficiency of covalently attached liquid-like surfaces
Authors: Katselas Anthony , Gresham Isaac J. , Nelson Andrew R. J. , Neto Chiara
Published: June 2023

The capture of moisture from the atmosphere through condensation has the potential to provide a sustainable source of water. Here, we investigate the condensation of humid air at low subcooling condition (11 °C), similar to conditions for natural dew capture, and explore how water contact angle and contact angle hysteresis affect the rates of water capture. We compare water collection on three families of surfaces: (i) hydrophilic (polyethylene oxide, MPEO) and hydrophobic (polydimethylsiloxane, PDMS) molecularly thin coatings grafted on smooth silicon wafers, which produce slippery covalently attached liquid surfaces (SCALSs), with low contact angle hysteresis (CAH = 6°); (ii) the same coatings grafted on rougher glass, with high CAH (20°–25°); (iii) hydrophilic polymer surfaces [poly(N-vinylpyrrolidone), PNVP] with high CAH (30°). Upon exposure to water, the MPEO SCALS swell, which likely further increases their droplet shedding ability. MPEO and PDMS coatings collect similar volume of water (around 5 l m−2 day−1), both when they are SCALS and non-slippery. Both MPEO and PDMS layers collect about 20% more water than PNVP surfaces. We present a basic model showing that, under low heat flux conditions, on all MPEO and PDMS layers, the droplets are so small (600–2000 µm) that there is no/low heat conduction resistance across the droplets, irrespective of the exact value of contact angle and CAH. As the time to first droplet departure is much faster on MPEO SCALS (28 min) than on PDMS SCALS (90 min), slippery hydrophilic surfaces are preferable in dew collection applications where the collection time frame is limited.
Evaluating the molecular weight distribution of ultrahigh molecular weight polypropylene through rheology
Authors: Ianniello Vincenzo , Costanzo Salvatore , Pasquino Rossana , Ianniruberto Giovanni , Gupta Virendra K , Stieglitz Lucas , Rieger Bernhard , Tervoort Theo , Grizzuti Nino
Published: June 2023

This work investigates the possibility of obtaining the molecular weight distribution (MWD) of linear ultrahigh molecular weight (UHMW) polypropylene (PP) through rheology. To this end, the linear viscoelastic response of a set of UHMWPP samples is measured over the largest possible frequency range. The terminal relaxation is achieved by running creep experiments and converting the compliance in dynamic moduli. A time–temperature concentration principle, recently validated for UHMW polyethylene, is also applied to obtain the terminal relaxation of the sample with the largest molecular weight. The linear rheological response is correlated with gel permeation chromatography (GPC) results by means of the mixing rule based on the relaxation modulus. The implementation of such a rule requires the knowledge of some material parameters governing the stress relaxation of the polymer. Since they are unknown in literature for PP, they are estimated from the comparison between the viscoelastic spectra and the GPC distributions of three lab-made UHMWPPs with narrow polydispersity. Such parameters are then used as a basis to predict the MWDs of two UHMWPP samples with large polydispersity. The variability of the parameters upon molecular weight and polydispersity is assessed by applying the mixing rule to two different PP samples with lower molecular weights, one with narrow polydyspersity and another one with broad polydispersity. As the GPC curves of the samples are available, first the direct problem of estimating the rheological response from MWD and then the inverse problem of obtaining the MWD from the rheological data are solved. An overall satisfactory agreement is found between the calculated and measured MWD for the two samples, with both the direct and inverse approach.
High-efficiency oxygen electrocatalyst for Zn-air batteries on CoMn alloy encapsulated in N-doped carbon architectures
Authors: Zhou Wenshu , Liu Yanyan , Wu Dichao , Liu Shuling , Zhang Pengxiang , Zhang Gaoyue , Sun Kang , Jiang Jianchun
Published: June 2023

A low-cost efficient electrocatalyst for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is urgently required for the commercialization of Zn-air batteries. Herein, CoMn nanoalloys encapsulated in nitrogen-doped hollow carbon architectures (CoMn@NHC) as dual electrocatalysts for Zn-air batteries were developed successfully. The obtained CoMn@NHC nanohybrid expresses excellent electrocatalytic performances for ORR (E1/2 = 0.87 V) and OER (Ei=10 = 1.51 V). More encouragingly, a homemade aqueous Zn-air battery using CoMn@NHC catalyst delivers a larger peak power density of 92.3 mW cm−2 and excellent stability of nearly 300 h, outperforming the commercial Pt/C + RuO2. The remarkable electrocatalytic performances are owing to the unique microstructure and the synergistic effect between CoMn alloy and N-doped carbon substrate. This study opens a new way for designing high-efficient bifunctional electrocatalysts for application in renewable energy facilities.
A linear stability analysis of instabilities with reactive flows in porous medium
Authors: Sharma Vandita , Chen Ching-Yao , Mishra Manoranjan
Published: June 2023

Convection, diffusion, and reaction dynamics of radial displacement of reactive fluids undergoing second-order chemical reaction in a porous medium are modeled and understood numerically. In the case of iso-viscous reactants and products, reaction dynamics are examined to understand the effect of reaction rate after solving a system of convection–diffusion–reaction equations using a method of lines. Various temporal scalings for reaction characteristics like the total amount of product and width of reaction front are obtained in terms of the Damköhler number (Da) for the first time in this work. The generation of the product having different viscosity than the reactants results in a hydrodynamic instability called viscous fingering. The numerical technique based on hybrids of compact finite difference and pseudo-spectral methods is utilized, for the first time, for the linear stability analysis (LSA) of miscible viscous fingering induced by chemical reaction. The onset time of instability (ton) is found to depend on the reaction rate, and we obtain a stable zone sandwiched between two unstable zones in the Mc,ton plane for a fixed Péclet number and Damköhler number, where Mc is the log-mobility ratio. The results agree with existing numerical studies validating the novel LSA technique utilized.
Materials cartography: A forward-looking perspective on materials representation and devising better maps
Authors: Torrisi Steven B. , Bazant Martin Z. , Cohen Alexander E. , Cho Min Gee , Hummelshøj Jens S. , Hung Linda , Kamat Gaurav , Khajeh Arash , Kolluru Adeesh , Lei Xiangyun , Ling Handong , Montoya Joseph H. , Mueller Tim , Palizhati Aini , Paren Benjamin A. , Phan Brandon , Pietryga Jacob , Sandraz Elodie , Schweigert Daniel , Shao-Horn Yang , Trewartha Amalie , Zhu Ruijie , Zhuang Debbie , Sun Shijing
Published: June 2023

Machine learning (ML) is gaining popularity as a tool for materials scientists to accelerate computation, automate data analysis, and predict materials properties. The representation of input material features is critical to the accuracy, interpretability, and generalizability of data-driven models for scientific research. In this Perspective, we discuss a few central challenges faced by ML practitioners in developing meaningful representations, including handling the complexity of real-world industry-relevant materials, combining theory and experimental data sources, and describing scientific phenomena across timescales and length scales. We present several promising directions for future research: devising representations of varied experimental conditions and observations, the need to find ways to integrate machine learning into laboratory practices, and making multi-scale informatics toolkits to bridge the gaps between atoms, materials, and devices.
Large eddy simulation within the smoothed particle hydrodynamics: Applications to multiphase flows
Authors: Meringolo Domenico Davide , Lauria Agostino , Aristodemo Francesco , Filianoti Pasquale Fabio
Published: June 2023

In this paper, the large eddy simulation (LES) model introduced in the smoothed particle hydrodynamics (SPH) by Di Mascio et al. [Phys. Fluids 29, 035102 (2017)] and called δ-LES-SPH, is extended to treat multiphase flows. This is achieved by modifying the multiphase δ-SPH by Hammani et al. [Comput. Methods Appl. Mech. Eng. 368, 113189 (2020)] by switching the viscous and density diffusion constants to dynamic variables evaluated as turbulence closure terms. The equation for energy conservation is also written for the presented model. The validation is performed for two-dimensional problems, by comparison with other established SPH solvers, with a finite volume method solver based on the turbulence closure corresponding to that adopted for the Lagrangian scheme, and with experimental data. The first test case investigated is a modified Taylor–Green vortex in which the introduction of macro-bubbles of a lighter fluid phase inside the domain is considered. In the second test case, a more violent problem involving wave breaking and splashing dynamics is analyzed. In the final test, the dynamic of a sloshing problem is reproduced. An analysis of turbulence resolution is conducted by considering modeled and resolved turbulent kinetic energies, as well as viscous dissipation and turbulent viscosity dissipation.
Ionization potentials of metal clusters studied with a broad range, tunable vacuum ultraviolet light source
Authors: Macion A. , Schäfer R.
Published: June 2023

In this work, we present an alternative to complex laser setups or synchrotron light sources to accurately measure the ionization potentials of metal clusters. The setup is based on a commercial Xe flash lamp, combined with a vacuum monochromator, and has been applied to determine the ionization potentials of Snn clusters with n = 8–12 atoms. The uncertainty in the determination of the ionization potentials is mainly caused by the bandwidth of the monochromator. The adiabatic ionization potentials (AIPs) are extracted from experimental photoionization efficiency curves. Franck–Condon simulations are additionally used to interpret the shape and onset of the photo-ion yield. The obtained AIPs are (all energies are in eV) Sn8 (6.53 ± 0.05), Sn9 (6.69 ± 0.04), Sn10 (6.93 ± 0.03), Sn11 (6.34 ± 0.05), and Sn12 (IsoI 6.64 ± 0.04 and IsoIII 6.36 ± 0.05). Furthermore, the impact of multiple isomers present in the experiment on the photo-ion yield is addressed and compared with other experimental data in the literature.
A genome dependence of metastable phase selection on atomic structure for undercooled liquid Nb90Si10 hypoeutectic alloy
Authors: Wang Q. , Zheng C. H. , Li M. X. , Hu L. , Wang H. P. , Wei B.
Published: June 2023

The phase selection mechanism within undercooled liquid Nb90Si10 hypoeutectic alloy was investigated by electrostatic levitation technique combined with deep neural network molecular dynamics. A stepwise-solidification procedure was conducted, where the primary phase and eutectic microstructure successively solidified from undercooled liquid alloy and undercooled residual liquid, respectively. The intermetallic phase of the eutectic structure transfers from Nb3Si to βNb5Si3 and finally into αNb5Si3 compound with the increase in liquid undercooling. The deep neural network molecular dynamic simulations have shown that the phase selection between Nb3Si and Nb5Si3 is mainly controlled by the short-range order of residual liquid, considering that the predominant short-range configuration transforms from Nb3Si-like to Nb5Si3-like structures. The αNb5Si3-like medium-range order, which is characterized by vertex-connected ⟨0,2,8,4⟩ clusters, is shown to significantly influence the competitive nucleation of the αNb5Si3 and βNb5Si3 phases. The residual liquid favors the αNb5Si3-like medium-range order rather than βNb5Si3 at large undercoolings, which explains the transformation from βNb5Si3 to αNb5Si3.
Determining the spin wave exchange constant of ferromagnets using canted high-order exchange magnons
Authors: Shin Yooleemi , Yoon Seongsoo , Hong Jung-Il , Kim Ji-Wan
Published: June 2023

We propose an alternative method for obtaining the spin wave exchange constant of a ferromagnetic material. This involves generating and detecting canted high-order magnons in Co films using a time-resolved magneto-optical Kerr effect instrument, which enables the extraction of the spin wave exchange constant in a single film thickness in a reliable manner. To enhance the sensitivity of high-order magnon detection, we perform simultaneous measurements of differential Kerr rotation and ellipticity on both sides of the film. This method will be particularly useful in practical situations where the magnetic properties of a material vary with thickness or where it is not feasible to produce films of the same quality.
Investigation of the significance of excited species in wave-heated dense non-ideal microplasmas using particle-in-cell Monte Carlo-collision modeling
Authors: Solmaz Evrim , Levko Dmitry , Raja Laxminarayan L.
Published: June 2023

A computational model for the interaction of a high-pressure microplasma with an electromagnetic wave is presented. A one-dimensional particle-in-cell Monte Carlo collision model is used to investigate the plasma non-ideality effects in a second-stage laser-heated xenon plasma with a comprehensive chemistry mechanism, including excited species. A xenon microplasma at a temperature of 300 K and pressure of 10 bar becomes non-ideal after the laser heating stage with lower ionization and electronic excitation barriers, which makes the presence of excited species important to the plasma generation process. For these conditions, two-step ionization via excited species becomes a major contributor to plasma ionization. We find that full ionization of the plasma is obtained in ∼2 ps when excited species are included in the chemistry model, as opposed to ∼2.5 ps for a chemistry mechanism that does not consider their effect. With excited species, the ionization mode transitions from direct ionization via electron-neutral collisions to direct and stepwise ionization as the plasma generation progresses.