bluuebunny/crossref_metadata_2025 huggingface dataset:
Challenges in ensuring stability whilst providing environmental compliance for existing TSFs
Authors: Zannoni Edoardo , Govender Vernita , Germishuys Morne
Published: September 2024

The stringent requirements for tailings storage facilities (TSF) following the publishing of the Global Industry Standards for Tailings Management (GISTM) have required in depth stability supported by advance testing and modelling, where in the presence of a hazardous tailings facility would require knowledge of the barrier system. Often a buttress is required to increase the factor of safety from the one originally designed, complying with stability as well as environmental requirements, and most importantly without triggering any failure during construction. The paper aim to present a project where the facility requires a buttress as the original design in the early 2000’s was not acceptable in today’s requirements. The stability pivot over a multi-layered barrier system (which does not allow Mohr-Coulomb failure criterion) and the different waste classification between the tailings and the buttress material, requiring different barrier requirements, yet to all be tailored in a constructible solution, without affecting the stability of the TSF.
Geomembrane displacement monitoring system installed in a multilayered cover at the Aldermac mine site
Authors: Rarison R. Faneva M. , Hanson James L. , Bussière Bruno , Mbonimpa Mamert , Yesiller Nazli , Aubertin Michel
Published: September 2024

The abandoned Aldermac mine site, located in the Abitibi- Témiscamingue region of Québec, Canada, is a former polymetallic mine that operated in the 1930s. Over the decades, the sulfidic mine wastes produced by the mine have been exposed to atmospheric conditions, leading to the generation of acid mine drainage (AMD) and contamination of the surrounding environment. In 2008–2009, reclamation works were initiated by the Québec government with the implementation of different techniques based on the characteristics of the different sectors of the mine site. In the southern sector, the production of AMD from the mine wastes pile is controlled by a multilayered cover system, including a 1.5 mm-thick textured high-density polyethylene geomembrane, aimed at limiting ingress of water and oxygen. In 2021, work was carried out to instrument the cover system with an innovative displacement measurement system that was developed and applied to the geomembrane along a sloping transect. The system allows continuous measurements of geomembrane displacement at three locations. This article discusses the installation of these instruments and presents preliminary results. Displacements over a 1-year monitoring period ranged from approximately 4 mm downslope to 32 mm upslope. This corresponded to strains ranged from approximately 0.01% contraction to 0.05% tension.
Shear fatigue behavior of geosynthetic-reinforced asphalt layers
Authors: Silva Matheus P. S. , Correia Natália S.
Published: September 2024

The factors influencing bonding between geosynthetics, and asphalt layers have been extensively investigated through monotonic interface shear tests. However, little is known about how the geosynthetic pavement interlayers behaves under cyclic shear loading. Dynamic shear testing is recognized as more appropriate to understand the performance of pavements under traffic loads. This paper presents the characterization of bond stiffness and shear fatigue life using dynamic interface shear tests on three different geosynthetic-reinforced asphalt interlayers, including a geogrid and two reinforcement geocomposites. Double-layered samples of 150 mm diameter were compacted in the laboratory using Marshall adapted method. The dynamic interlayer shear behavior was evaluated using cyclic Leutner device at a frequency of 5 Hz. The bitumen coating content and thickness of the fabric backing showed to most influence the shear fatigue life of geosynthetic interlayers. This research shows that distinct shear fatigue behaviors were obtained for the different types of geosynthetics.
Geosynthetic solutions for road stabilization and railway ballast optimization over frost susceptible and expansive clays: A case study of the Cargill Canola processing facility
Authors: Laprade René , Nesbit Brock
Published: September 2024

The Cargill Canola processing facility, a $350 million project, began construction in July 2022 and is set to be operational in 2025. The site's geology primarily consists of fine-grained glaciolacustrine sediments, mainly silts and clays. A significant geotechnical challenge was the presence of a weak upper silty clay soil layer, approximately 10 metres thick, which was susceptible to frost heave during freezing temperatures and volumetric changes due to water exposure. Spring melt also raised concerns about excess water accumulation weakening the subgrade, leading to structural damage. The high plasticity index of the subgrade increased the potential for swelling in warmer conditions, complicating the design challenges during seasonal transitions. To address these issues, geosynthetics were employed. Three types were used: a moisture management woven geotextile to provide hydraulic and mechanical stabilization in the rail and road structures, an integrated high-modulus woven geotextile to provide ballast reinforcement, and a biaxial geogrid for base reinforcement in the access roads. The integrated high-modulus woven geotextile was also used in staging areas and gravel pavements to reduce the amount of granular base material required. This case study offers valuable insights for geosynthetic solutions in stabilizing roads and optimizing railway ballast over frost-susceptible and expansive clays. It demonstrates the effectiveness of geosynthetics in mitigating challenges posed by weak soils, frost susceptibility, and expansive clays, contributing to more resilient infrastructure designs.
Base reinforcement on the railway platform at the Buenos Aires Retiro Station
Authors: Mendiz Augusto , de Loyola Felipe , dal Farra Federico
Published: September 2024

Within the framework of the renovation of the Retiro train station located in the city of Buenos Aires, this work describes the main technical aspects of the design and implementation of the improvement of the railway yards’ base using reinforcement geosynthetics, particularly on the Mitre and San Martin lines. In replacement of traditional methods involving lime treatment, this project employed biaxial polypropylene geogrids at the formation level, allowing the achievement of the necessary support condition for the track superstructure. This took into consideration the short working windows and the environmental benefit of reusing recycled ballast, resulting in a significant reduction in the duration of the tasks. In addition to reinforcement, the inclusion of a non-woven geotextile with filtering and separation functions just below the ballast enhances surface water drainage and prevents the migration of fine soils into the gravel, maintaining its properties and improving the load-bearing capacity of the ballast.
What Is Culture Made of? An Exploratory Study of Ethical Cultures and Provider Perspectives on the Care of Periviable Neonates
Authors: Adams Shannon Y. , Fry Jessica T. , Henner Natalia
Published: September 2024

Objective Studies examining intercenter variation in neonatal intensive care unit practices at the limits of fetal viability have hypothesized that institutional “culture” can be one of many factors that impact patient care. This study aimed to describe institutional culture at a single, large academic center with regard to the antenatal consultation, resuscitation, and postnatal management of periviable neonates.

Study Design Members of six clinical groups—attending and fellow maternal–fetal medicine physicians, attending and fellow neonatal–perinatal medicine physicians, neonatal nurses, advanced practiced neonatal nurses, pediatric hospitalist physicians, and neonatal respiratory therapists—were invited to complete qualitative, semi-structured interviews. All audio recordings were transcribed. Dedoose software was used to complete team-based coding and thematic analysis.

Results Twenty-two interviews were completed. Thematic analysis revealed three central themes described by participants as contributory to institutional culture: Perception, referring to factors based on individual attitudes and insights, Statements of Information, referring to factors anchored in more objective concepts such as outcomes data and institutional policy, and Dynamic Factors, referring to the relatively fluid factors of institutional culture that interact with both Perception and Statements of Information. Participants were more likely to mention factors in the Perception category (n = 430) compared with factors in the Information category (n = 225), and although the latter were described as critical components of antenatal counseling and perinatal management, the philosophy of our unit appeared to be more heavily rooted in institutional memory and individual belief systems.

Conclusion Our data demonstrate a personal undertone to institutional culture at the limits of viability, with an emphasis on individual attitudes and subjective interpretations of fact rather than empirical data. As the landscape of neonatology continues to change, understanding those factors that contribute to culture remains a necessary step toward deconstructing institutional belief systems and optimizing clinical care.

Key Points
Polymorphism in the Drug Transporter Gene ABCB1 as a Potential
Disease Modifier in Cortisol-Producing Adrenal Adenomas
Authors: Vogel Frederick , Braun Leah , Vetrivel Sharmilee , Zhang Ru , Zopp Stephanie , Oßwald Andrea , Nowak Elisabeth , Schilbach Katharina , Bidlingmaier Martin , Zimmermann Petra , Beuschlein Felix , Hartmann Michaela , Wudy Stefan , Riester Anna , Reincke Martin
Published: September 2024

Introduction Endogenous hypercortisolism presents with variable
phenotypes. Etiological factors accounting for the level of hypercortisolism or
varying severity of associated comorbidities are lacking. Recently, the adrenal
ATP-binding cassette B1 (ABCB1) gene was identified as a modulator of
glucocorticoid secretion.

Objective To evaluate the effect of ABCB1
polymorphism rs2032582 on steroid metabolome and clinical phenotypes in patients
with endogenous hypercortisolism.

Methods In this cross-sectional cohort study, 137 patients prospectively
enrolled in the German Cushing’s registry were included (41 with ACTH-producing
pituitary adenoma, 21 with cortisol-producing adrenal adenoma, and 75 with
excluded hypercortisolism). In all patients, ABCB1 polymorphism was analyzed
using a TaqMan genotyping assay, glucocorticoid metabolite excretion in 24-hour
urine samples was analyzed by gas chromatography-mass spectrometry, and the
clinical phenotype was assessed systematically.

Results In patients with cortisol-producing adrenal adenomas, but not in
patients with ACTH-producing pituitary adenomas, homozygous major allele GG of
ABCB1 polymorphism rs2032582 was associated with higher overall cortisol
metabolite secretion (median 13515 [IQR 10347; 25669] µg/24h vs. 9645 [6146;
10732] µg/24h in minor homo- and heterozygotes, p=0.036) and elevated major
cortisol metabolites αTHF, THF and THE (9339 [6929; 17789] µg/24h vs. 6288
[4184; 7455] µg/24h, p=0.045). Moreover, these patients showed higher mean
arterial pressure (116 [111; 131] mmHg in major homozygotes vs. 105 [96; 112]
mmHg in minor homo- and heterozygotes, p=0.036).

Conclusion The genotype of drug transporter gene ABCB1 rs2032582
polymorphism is associated with the degree of cortisol metabolite secretion in
cortisol-producing adrenal adenomas and could, therefore, represent a modifier
of disease severity in this context.
Risk of Recurrent Venous Thromboembolism in Patients with Cancer: An Individual Patient Data Meta-analysis and Development of a Prediction Model
Authors: Lanting Vincent R. , Takada Toshihiko , Bosch Floris T. M. , Marshall Andrea , Grosso Michael A. , Young Annie M. , Lee Agnes Y. Y. , Di Nisio Marcello , Raskob Gary E. , Kamphuisen Pieter W. , Büller Harry R. , van Es Nick
Published: September 2024

Background About 7% of patients with cancer-associated venous thromboembolism (CAT) develop a recurrence during anticoagulant treatment. Identification of high-risk patients may help guide treatment decisions.

Aim To identify clinical predictors and develop a prediction model for on-treatment recurrent CAT.

Methods For this individual patient data meta-analysis, we used data from four randomized controlled trials evaluating low-molecular-weight heparin or direct oral anticoagulants (DOACs) for CAT (Hokusai VTE Cancer, SELECT-D, CLOT, and CATCH). The primary outcome was adjudicated on-treatment recurrent CAT during a 6-month follow-up. A clinical prediction model was developed using multivariable logistic regression analysis with backward selection. This model was validated using internal–external cross-validation. Performance was assessed by the c-statistic and a calibration plot.

Results After excluding patients using vitamin K antagonists, the combined dataset comprised 2,245 patients with cancer and acute CAT who were treated with edoxaban (23%), rivaroxaban (9%), dalteparin (47%), or tinzaparin (20%). Recurrent on-treatment CAT during the 6-month follow-up occurred in 150 (6.7%) patients. Predictors included in the final model were age (restricted cubic spline), breast cancer (odds ratio [OR]: 0.42; 95% confidence interval [CI]: 0.20–0.87), metastatic disease (OR: 1.44; 95% CI: 1.01–2.05), treatment with DOAC (OR: 0.66; 95% CI: 0.44–0.98), and deep vein thrombosis only as an index event (OR: 1.72; 95% CI: 1.31–2.27). The c-statistic of the model was 0.63 (95% CI: 0.54–0.72) after internal–external cross-validation. Calibration varied across studies.

Conclusion The prediction model for recurrent CAT included five clinical predictors and has only modest discrimination. Prediction of recurrent CAT at the initiation of anticoagulation remains challenging.
Merging the Reactivity of (Pseudo)cyclic Hypervalent Iodine Reagents and Carbenes or Carbenoids
Authors: Ramirez Nieves P. , Waser Jerome
Published: September 2024

In this short review, we present applications merging the reactivity of cyclic hypervalent iodine reagents with carbenes and carbenoids developed in the period 2014–2024. The use of more stable cyclic hypervalent iodine reagents has led to major advances in this area. The combination of iodine(III) chemistry with carbenes or carbenoids enables new disconnections that are not possible using classical reactivity. Both the use of hypervalent iodine compounds as partners in reactions with metal carbenes and as reagents combining the reactivity of iodine(III) and carbenes in a single molecule to give carbyne equivalents are discussed in this review.

1 Introduction

2 Transfer of Fluorinated Groups (F, CF3)

3 Oxy- and Aminoalkyn(en)ylation

3.1 Oxy- and Aminoalkynylation with Acceptor-Substituted Diazo Compounds

3.2 Oxyalkenylation with Acceptor-Substituted Diazo Compounds

3.3 Oxyalkynylation with Acceptor-Acceptor-Substituted Diazo Compounds

4 Carbyne Equivalents

4.1 Diazo-Based Reagents

4.2 Sulfur Ylide Based Reagents

5 Conclusion
Chemical Profiling, In Silico Pharmacokinetics Analysis and Molecular Docking Study of Phytocompounds of Homeopathy Medicine Echinacea angustifolia Q against Suppurative Bacterial Proteins
Authors: V. Kumaravel , Singh Supriya , Paul Subhrajit , Shaw Niharika , T. Austin Jose
Published: September 2024

Background Computer-aided drug design is the emerging field for identification of drug action on its target organs. The pharmacokinetic study helps find out drug ADMET (absorption, distribution, metabolism, excretion, and toxicity) and drug likeness properties. PyRx software helps with molecular docking of the bioactive compounds on their target organ within a short period of time. In homeopathy, Echinacea angustifolia is one of the most commonly used drugs for microbial infective skin lesions used in internal administration as well as an external application.

Objectives This study was aimed at identifying the compounds present in Echinacea angustifolia Q through liquid chromatography mass spectrometry (LC-MS), ADMET, and drug likeness properties, followed by molecular docking by PyRx software to recognize the interaction between drug compounds against 12 target microbial proteins of commonly infective suppurative bacteria.

Materials and Methods An analysis of the phytoconstituents of Echinacea angustifolia Q was performed using the Agilent 1290 Infinity LC system coupled to the Agilent 6545 Accurate Mass Quadrupole Time-of-Flight (QTOF) with Agilent Jet Stream Thermal Gradient Technology. In silico ADMET and drug likeness properties were assessed by free online tools, followed by a detailed docking study by PyRx software. The drug compounds with the lower glide docking score are considered to have the best binding affinity.

Result The five compounds of Echinacea angustifolia Q satisfy all properties of ADMET and drug likeness. The three compounds of Echinacea angustifolia Q have low glide score of >-7.0 kcal/mol against the three microbial target proteins of Salmonella enterica, Proteus mirabilis, and Staphylococcus aureus.

Conclusion Echinacea angustifolia Q has fulfilled the ADMET and drug-likeness properties for internal administration as well as external application for various suppurative bacterial infective disorders, which were confirmed through molecular docking. Therefore, Echinacea angustifolia Q may function as a potential therapeutic agent for the treatment of illnesses associated with antimicrobial resistance.
The Prevalence and Awareness of Congenital External Ear Deformity among the School-Age Group: A Cross-Sectional Study
Authors: Alshehri Ali Abdullah , Al Hadi Asaiel Mubarak , Alyami Lama Hassan Ahmed , Al Sulaiman Ibrahim Nasser , Al Hadi Enas Mubarak , Al Hareth Saleh Yahya
Published: September 2024

Introduction and Purpose Congenital outer ear deformities stem from a sequence of disturbances during fetal auricular cartilage embryonic development. A significant gap exists in understanding their prevalence among the school-age group in Saudi Arabia. This cross-sectional study aims to address this knowledge gap to raise awareness about the impact of such disorders.

Methodology This cross-sectional study targeted parents of children in the school-age group. A multistage cluster sampling technique was employed to ensure the representation of schools. A self-administered Google form survey was used. Data were analyzed using IBM SPSS Statistics for Windows, Version 28.0 (IBM Corp., Armonk, NY).

Results Our study revealed that the majority were males (56.2%), aged 6 to 10 years (49.3%), and attended primary school (69.5%). Chronic illnesses were present in 7.1% of children, with hearing impairment most prevalent (25.9%). Congenital ear deformities affected 2.7% of children, primarily Stahl's ear (35.4%). Limited knowledge about these deformities was observed among respondents (30.3%), yet a significant majority (73.9%) expressed belief in the potential of community awareness to decrease deformity prevalence. The awareness levels were impacted by parental education but showed no significant association with the child's age, gender, or presence of chronic diseases.

Conclusion Our study underscores the noteworthy occurrence of congenital ear deformities among the school-age group, coupled with a notable lack of awareness. Parental education emerges as a key factor influencing awareness levels. It is imperative to prioritize initiatives to bolster awareness and early detection to promote child health.
European Reference Network eUROGEN Guidelines on the Management of Anorectal Malformations, Part II: Treatment
Authors: Aubert Ophelia , Irvine Willemijn F. E. , Aminoff Dalia , de Blaauw Ivo , Cascio Salvatore , Cretolle Célia , Iacobelli Barbara Daniela , Mantzios Konstantinos , Midrio Paola , Miserez Marc , Sarnacki Sabine , Schmiedeke Eberhard , Schwarzer Nicole , Sloots Cornelius , Stenström Pernilla , Lacher Martin , Gosemann Jan-Hendrik
Published: September 2024

Introduction Anorectal malformations (ARMs) are rare birth defects affecting the anorectum and oftentimes the genitourinary region. The management of ARM patients is complex and requires highly specialized surgical and medical care. The European Reference Network eUROGEN for rare and complex urogenital conditions aimed to develop comprehensive guidelines for the management of ARM applicable on a European level.

Methods The Dutch Quality Standard for ARM served as the basis for the development of guidelines. Literature was searched in Medline, Embase, and Cochrane. The ADAPTE method was utilized to incorporate the newest available evidence. A panel of 15 experts from seven European countries assessed currency, acceptability, and applicability of recommendations. Recommendations from the Dutch Quality Standard were adapted, adopted, or rejected and recommendations were formed considering the current evidence, expert opinion, and the European context.

Results Surgical and medical treatment of ARM, postoperative instructions, toilet training, and management of fecal and urinary incontinence were addressed. Seven new studies were identified. The panel adapted 23 recommendations, adopted 3, and developed 8 de novo. The overall level of newly found evidence was considered low.

Conclusion Treatment of ARM patients requires a multidisciplinary team and expertise about anatomical and surgical aspects of the disease, as well as long-term follow-up. This guideline offers recommendations for surgical and medical treatment of ARM and associated complications, according to the best available evidence and applicable on a European level.
Magnetic heating of interacting nanoparticles under different driving field waveforms
Authors: Ortega-Julia J. , Ortega D. , Leliaert J.
Published: September 2024

This study explores the impact of different magnetic driving field waveforms on nanoparticle heating in magnetic hyperthermia. Our research, which shifts the usual focus from individual nanoparticle properties to interacting particle clusters, evidences that square waves induce more uniform and greater heating than sinusoidal waves. The sequential switching observed with sinusoidal waves, which additionally strongly depends on the alignment of the particle cluster with respect to the direction of the field, leads to less uniform heating within and among different clusters. In contrast, a square waveform leads to simultaneous particle switching, thereby homogenizing the heat and potentially mitigating hazardous hot spots. These findings reaffirm the potential advantages for magnetic hyperthermia treatments using non-harmonic field waveforms, offering more uniform heating and the possibility of reducing the applied field exposure.
Compact laser wakefield acceleration toward high energy with micro-plasma parabola
Authors: Geng Xuesong , Xu Tongjun , Zhang Lingang , Kostyukov Igor , Pukhov Alexander , Shen Baifei , Ji Liangliang
Published: September 2024

Laser wakefield acceleration (LWFA) promises compact accelerators toward the high-energy frontier. However, the approach to the 100 GeV milestone faces the obstacle of the long focal length required for optimal acceleration with high-power lasers, which reaches hundreds of meters for 10–100 PW lasers. The long focal length originates from optimal laser intensity required to avoid nonlinear effects and hence large spot size and Rayleigh length. We propose a “telescope” geometry in which a micro-plasma parabola (MPP) is coupled with a short-focal-length off-axis parabola, minimizing the focal length to the meter range for LWFA under optimized conditions driven by lasers beyond 1 PW. Full-dimensional kinetic simulations demonstrate the generation of a 9 GeV electron bunch within only 1 m optical length—only one-tenth of that required with the conventional approach with the same performance. The proposed MPP provides a basis for the construction of compact LWFAs toward single-stage 100 GeV acceleration with 100 PW class lasers.
Influence of different factors on gap breakdown process with hot electrode and high temperature gas medium in low voltage circuit breaker chamber based on particle-in-cell/Monte-Carlo collision simulation
Authors: Wang Lijun , Hu Runze , Chen Zhuo , Wang Zhiwei , Wang Yile
Published: September 2024

Different factors such as gas composition inside the low voltage circuit breaker (LVCB) chamber and the residual plasma in the post-arc stage affect the breakdown process, which in turn affects the breaking capacity of LVCBs. In this paper, the effects of non-parallel electrode structure, gas temperature and pressure, electrode temperature, and gap distance on gap breakdown of hot electrode under high temperature gas conditions were studied, for which a particle-in-cell/Monte-Carlo collision simulation model has been established, which takes into account the effects of high-temperature gas components, cathode electron thermal emission, electron collision ionization and other effects, and simulation studies have been conducted. The simulation results show that the increase in gap gas temperature, the decrease in air pressure, and the increase in electrode temperature will lead to the gap breakdown more easily. With the increase in the gap length, the breakdown voltage increases, but the average electric field intensity required for breakdown decreases. In the non-parallel electrode structure, the breakdown occurs first at the position with the shortest gap distance, then the cathode sheath forms and extends along the electrode surface to other areas, and finally, the entire gap breaks down.
In situ study of microstructure evolution and α → ω phase transition in annealed and pre-deformed Zr under hydrostatic loading
Authors: Pandey K. K. , Levitas Valery I. , Park Changyong , Shen Guoyin
Published: September 2024

The detailed study of the effect of the initial microstructure on its evolution under hydrostatic compression before, during, and after the irreversible α→ω phase transformation and during pressure release in Zr using in situ x-ray diffraction is presented. Two samples were studied: one is plastically pre-deformed Zr with saturated hardness and the other is annealed. Phase transformation α→ω initiates at lower pressure for a pre-deformed sample but for a volume fraction of ω Zr, c>0.7, a larger volume fraction is observed for the annealed sample. This implies that the proportionality between the athermal resistance to the transformation and the yield strength in the continuum phase transformation theory is invalid; an advanced version of the theory is outlined. Phenomenological plasticity theory under hydrostatic loading is outlined in terms of microstructural parameters, and plastic strain is estimated. During transformation, the first rule is suggested, i.e., the average domain size, microstrain, and dislocation density in ω Zr for c<0.8 are functions of the volume fraction, c of ω Zr only, which are independent of the plastic strain tensor prior to transformation and pressure. The microstructure is not inherited during phase transformation. Surprisingly, for the annealed sample, the final dislocation density and the average microstrain after pressure release in the ω phase are larger than for the severely pre-deformed sample. The results suggest that an extended experimental basis is required for the predictive models for the combined pressure-induced phase transformations and microstructure evolutions.
Multifractal dimension spectrum analysis for nuclear density distribution
Authors: Ma Weihu , Ma Yu-Gang , He Wanbing , Zhou Bo
Published: September 2024

We present an integral density method for calculating the multifractal dimension spectrum for nucleon distribution in atomic nuclei. This method is then applied to analyze the non-uniformity of density distribution in several typical types of nuclear matter distributions, including the Woods–Saxon distribution, halo structure, and tetrahedral α clustering. The subsequent discussion provides a comprehensive and detailed exploration of the results obtained. The multifractal dimension spectrum shows a remarkable sensitivity to the density distribution, establishing it as a simple and novel tool for studying the distribution of nucleons in nuclear multibody systems.
Focus control of a concave–convex ultrasonic gel lens in the radial direction
Authors: Tagashira K. , Harada Y. , Nakamura K. , Miki H. , Matsukawa M. , Koyama D.
Published: September 2024

Optical image stabilization (OIS) systems maintain the three-dimensional focal position of a lens through mechanical actuation systems. This paper examines an optical lens for OIS that utilizes ultrasound vibration to alter the focal position, not only in the depth direction but also in the radial direction. The lens has a simple structure with no mechanical moving parts and consists of an ultrasound transducer divided into four pieces, a glass disk, and a transparent viscoelastic gel film that functions as a lens. The acoustic radiation force generated by the resonant flexural vibration of the glass disk can alter the surface profile of the gel film, allowing for a variable-focus function. The concave and convex lenses can be interchanged using two resonant vibration modes: the standing-wave mode, in which the vibration loop appears at the center, and the traveling-wave mode, in which the vibration node appears at the center. The positions of ultrasound vibrations on the lens can be controlled in a two-dimensional plane by adjusting the driving amplitudes of each channel, thereby achieving focus control in the radial direction. The focusing characteristics of the lens are evaluated through ray-tracing simulation.
Selective incorporation of antimony into gallium nitride
Authors: Liu Yujie , Navid Ishtiaque Ahmed , Mi Zetian , Kioupakis Emmanouil
Published: September 2024

Dilute concentrations of antimony (Sb) incorporation into GaN induce strong bandgap bowing and tunable room-temperature photoluminescence from the UV to the green spectral regions. However, the atomistic details of the incorporation of Sb into the GaN host remain unclear. In this work, we use first-principles calculations to understand the thermodynamics of Sb substitution into GaN and its effect on the optical and Raman spectra. Although it is empirically considered that Sb is preferentially incorporated as an anion (Sb3−) into the N sublattice, we demonstrate that Sb can also be incorporated as a cation (Sb3+, Sb5+) into the metal sublattice. Our thermodynamic analysis demonstrates that SbN0, SbGa2+, and SbGa0 can co-exist under Ga-rich conditions in n-type samples. We further confirm the dual incorporation of Sb by calculating the vibrational frequencies of different anionic and cationic substitutions to explain the origins of experimentally observed additional Raman peaks of Sb-doped GaN. Moreover, the calculated band structures of different Sb substitutions into GaN explain the experimental photoluminescence and optical absorption spectra. Overall, our analysis suggests that the coexistence of Sb3−, Sb3+, and Sb5+ substitutions into GaN explains the totality of experimental measurements. Our results demonstrate that the selective incorporation of Sb into GaN (and potentially other group-V elements such as As, P, or Bi) by tuning the growth conditions can drastically modify the electronic properties, for applications in visible light emitters and photocatalysis.
Cluster intercalation of aluminum tetrachloride in AlN cathode: Exploration and analysis of aluminum ion batteries
Authors: He Shanshan , Li Leilei , Wu Yijin , He Shan , Guo Donghui
Published: September 2024

When chloroaluminate (AlCl4−) serves as the electrolyte, aluminum nitride (AlN) has shown promise as a cathode material in aluminum ion batteries. However, there is currently a lack of research on the mechanisms of charge transfer and cluster intercalation between AlCl4 and AlN cathode materials. Herein, first-principles calculations are employed to investigate the intercalation mechanism of AlCl4 within the AlN cathode. By calculating the formation energies of stage-1–5 AlN–AlCl4 intercalation compounds with the insertion of individual AlCl4 cluster, we found that the structure of the stage-4 intercalation compounds exhibits the highest stability, suggesting that when the clusters begin to intercalate, it is important to start with the formation of the stage-4 intercalation compounds. In the subsequent phases of the charging process (stages 1 and 2), the stabilized structure with four inserted clusters demonstrates two characteristics: the coexistence of standing and lying clusters and the insertion of two standing clusters in an upside-down doubly stacked configuration, which further improve the spatial utilization while maintaining the structural stability. In addition, we infer that a phenomenon of coexisting intercalation compounds with mixed stages will occur in the course of the charging and discharging processes. More importantly, the diffusion barrier of AlCl4 in AlN–AlCl4 intercalation compounds decreases with the reduction of stage number, ensuring the rate performance of batteries. Therefore, we expect that our work will contribute to comprehend the intercalation mechanism of AlCl4 into the AlN cathode materials of aluminum ion batteries, providing guidance for related experimental work.
Influence of carrier localization on photoluminescence emission from sub-monolayer quantum dot layers
Authors: Huang T.-Y. , Borrely T. , Yang Y.-C. , Alzeidan A. , Jacobsen G. M. , Teodoro M. D. , Quivy A. A. , Goldman R. S.
Published: September 2024

We have investigated the origins of photoluminescence from quantum dot (QD) layers prepared by alternating depositions of sub-monolayers and a few monolayers of size-mismatched species, termed as sub-monolayer (SML) epitaxy, in comparison with their Stranski–Krastanov (SK) QD counterparts. Using measured nanostructure sizes and local In-compositions from local-electrode atom probe tomography as input into self-consistent Schrödinger–Poisson simulations, we compute the 3D confinement energies, probability densities, and photoluminescence (PL) spectra for both InAs/GaAs SML- and SK-QD layers. A comparison of the computed and measured PL spectra suggests one-dimensional electron confinement, with significant 3D hole localization in the SML-QD layers that contribute to their enhanced PL efficiency in comparison to their SK-QD counterparts.
Classical and quantum thermodynamics in a non-equilibrium regime: Application to thermostatic Stirling engine
Authors: Koyanagi Shoki , Tanimura Yoshitaka
Published: September 2024

We have developed a thermodynamic theory in the non-equilibrium regime, which we describe as a thermodynamic system–bath model [Koyanagi and Tanimura, J. Chem. Phys. 160, 234112 (2024)]. Based on the dimensionless (DL) minimum work principle, non-equilibrium thermodynamic potentials are expressed in terms of non-equilibrium extensive and intensive variables in time derivative form. This is made possible by incorporating the entropy production rate into the definition of non-equilibrium thermodynamic potentials. These potentials can be evaluated from the DL non-equilibrium-to-equilibrium minimum work principle, which is derived from the principle of DL minimum work and is equivalent to the second law of thermodynamics. We thus obtain the non-equilibrium Massieu–Planck potentials as entropic potentials and the non-equilibrium Helmholtz–Gibbs potentials as free energies. Unlike the fluctuation theorem and stochastic thermodynamics theory, this theory does not require the assumption of a factorized initial condition and is valid in the full quantum regime, where the system and bath are quantum mechanically entangled. Our results are numerically verified by simulating a thermostatic Stirling engine consisting of two isothermal processes and two thermostatic processes using the quantum hierarchical Fokker–Planck equations and the classical Kramers equation derived from the thermodynamic system–bath model. We then show that, from weak to strong system–bath interactions, the thermodynamic process can be analyzed using a non-equilibrium work diagram analogous to the equilibrium one for given time-dependent intensive variables. The results can be used to develop efficient heat machines in non-equilibrium regimes.
Research on the attenuation of internal pressure in the large-span cylindrical roof building with a dominant gable opening
Authors: Ge Yuhang , Sun Ying , Cao Zhenggang , Zhu Qiming
Published: September 2024

The internal to external pressure ratio in a large-span cylindrical roof building with a dominant gable opening fluctuates dramatically between 0 and 1, significantly impacted by the attenuation of internal pressure. Current theories usually assume this ratio equal to 1 and overlook the attenuation effect. This study investigates four cylindrical roof models with varying opening areas, scale ratios, and wind speeds by wind tunnel tests. It analyzes ratios of mean (C¯pi/C¯pe), fluctuating (σpi/σpe), and peak (Ĉpi/Ĉpe) internal to external pressure to pinpoint factors affecting the internal pressure attenuation. The results highlight that the most pronounced internal pressure attenuation is at the sideward opening. The vortex shedding around the opening is induced by the wind direction, scale ratio, and wind speed. The attenuation effect decreases with lower frequencies of periodic vortex shedding. This effect generally vanishes when the windward or leeward opening ratio (A1.5/V0) exceeds 0.57%. Empirical design formulas are proposed to predict ratios of internal to external pressure considering the attenuation effect. The inertia (CI) and loss coefficients (CL) affected by the internal pressure attenuation are analyzed to estimate the air slug inertia and damping through the opening. A governing equation, incorporating reduction coefficients (C¯eddy, C̃eddy) from empirical design formulas, is applied to precisely compute the attenuated internal pressure in the large-span cylindrical roof building with a dominant gable opening for engineering risk assessment.
Effects of Mach number on space-time characteristics of wall pressure fluctuations beneath turbulent boundary layers
Authors: Sun Xin-Hao , Zhang Peng-Jun-Yi , Zhao Kun , Wan Zhen-Hua , Sun De-Jun
Published: September 2024

Wall pressure fluctuations beneath turbulent boundary layers are a fundamental source of aerodynamic noise by exciting the wall structure, with their space-time characteristics serving as the basic ingredient for predicting the wall structural response. To this end, direct numerical simulations of fully developed compressible turbulent boundary layers at Mach numbers of 0.5, 1.2, and 2.0 are conducted to investigate wall pressure fluctuations comprehensively. The effects of Mach number on the single-point statistics of wall pressure fluctuations, such as the root mean square, skewness and flatness factors, probability density function, and frequency spectrum, are assessed to be very weak. Regarding the space-time characteristics, the convection velocity Uc determined by the space-time correlation of wall pressure fluctuations increases slightly with the Mach number, which only reflects the convective behavior of turbulent vortices. On the wavenumber–frequency spectrum, characteristic peaks of both the acoustic wave and convective vortices are identified. At Mach 0.5, the peaks of the fast (Uc+c) and slow (Uc−c) acoustic waves are unattached to others with c denoting acoustic speed, while only the peak of the fast acoustic wave is distinguishable from the convective peak at Mach 1.2 and 2.0. Due to the aerodynamic heating at supersonic conditions, the thermal effect on acoustic speed should be taken into account in determining the acoustic wavenumber. By introducing a convective Prandtl–Glauert parameter, a refined relation is proposed to provide a more accurate depiction of the acoustic domain in the wavenumber–frequency spectrum.
Optimal demodulation domain for microwave SQUID multiplexers in presence of readout system noise
Authors: García Redondo M. E. , Müller N. A. , Salum J. M. , Ferreyro L. P. , Bonilla-Neira J. D. , Geria J. M. , Bonaparte J. J. , Muscheid T. , Gartmann R. , Almela A. , Hampel M. R. , Fuster A. E. , Ardila-Perez L. E. , Wegner M. , Platino M. , Sander O. , Kempf S. , Weber M.
Published: September 2024

The Microwave SQUID Multiplexer (μMUX) is the device of choice for the readout of a large number of low-temperature detectors in a wide variety of experiments within the fields of astronomy and particle physics. While it offers large multiplexing factors, the system noise performance is highly dependent on the cold- and warm-readout electronic systems used to read it out, as well as the demodulation domain and parameters chosen. In order to understand the impact of the readout systems in the overall detection system noise performance, first, we extended the available μMUX simulation frameworks, including additive and multiplicative noise sources in the probing tones (i.e., phase and amplitude noise), along with the capability of demodulating the scientific data, either in the resonator’s phase or the scattering amplitude. Then, considering the additive noise as a dominant noise source, the optimum readout parameters to achieve minimum system noise were found for both open-loop and flux-ramp demodulation schemes in the aforementioned domains. Later, we evaluated the system noise sensitivity to multiplicative noise sources under the optimum readout parameters. Finally, as a case study, we evaluated the optimal demodulation domain and the expected system noise level for a typical software-defined radio readout system. This work leads to an improved system performance prediction and noise engineering based on the available readout electronics and the selected demodulation domain.
A first-principles study on structural stability and magnetoelectric coupling of two-dimensional BaTiO3 ultrathin film with Cr and Cu substituting Ti site
Authors: Gao Haigen , Wang Bing
Published: September 2024

A study on Jahn–Teller distortion reveals that the configuration with Ti-substitution is more stable than that in the case of Ba-replacement. However, magnetoelectric coupling is weak as no spontaneous polarization is formed in the doped unit cell. Taking the atomic radius, low price, and electronegativity into account, Cu was selected to replace Ti together with Cr. Formation energy and phonon spectrum show structural stability. The spontaneous polarization was calculated to be 0.110, 0.114, and 0.247 and 8.078, 0.288, and 0.255 μC/cm2, respectively, in the Cr- and Cu-doped unit cell, corresponding to the directions [100], [010], and [001]. With the application of electric fields, the total magnetic moment was generally enhanced, which resulted in a strong magnetoelectric coupling. In addition, the corresponding coefficient is more than 10 V/cmOe, indicating that the modified BaTiO3 may be a good candidate for single-phase multiferroics. Clearly, co-doping with nonferromagnetic and nonmagnetic elements increases the diversity of new multiferroics.
Heterogeneity properties and permeability of shale matrix at nano-scale and micron-scale
Authors: Hu Bowen , Ren Yongjie , Sun Rui , Wang Shengcheng , Su Shanjie
Published: September 2024

Heterogeneity of shale pores at nano-scale and micrometer-scale is of great significance to gas transport properties. In this study, the pore structure of shale samples from lower Silurian Longmaxi Formation in the Sichuan basin is investigated by field emission-scanning electron microscopy (FE-SEM) and x-ray micro-computed tomography (Xμ-CT) technology. Based on fractal theory, the lacunarity is introduced to describe the clustering degree of pores in shale matrix, which can compensate for the limitations of fractal dimension. Combining lacunarity with fractal dimension allows for quantification of subtle differences in pore spatial distribution. For FE-SEM images at nano-scales, the fractal dimension changes in a “U” shape, while lacunarity changes in a “∩” shape. For Xμ-CT images at micrometer-scale, both the fractal dimension and lacunarity change in a logarithmic function. Lacunarity at both nano-scale and micrometer-scale linearly decreases with the increase in fractal dimension. By three-dimensional (3D) pore network modeling analysis, the structure properties of the connected pores, such as the number of pores and throats, pore diameter, pore volume, pore surface, throat length, and coordination number, are quantitatively calculated, and these structure parameters show strong heterogeneity. The average coordination number of the connected pores ranges in 2.92–4.36. This indicates that these pores in shale matrix have poor connectivity. The permeability varies from 0.06 to 0.17 μm2 in two-dimensional (2D) Xμ-CT images but from 3.20 to 34.99 μm2 in a 3D structure. The permeability in the 3D structure is about two order higher in magnitude than that in the 2D Xμ-CT images.
Effects of axisymmetric confinement on vortical structures emanating from round turbulent jets
Authors: Adjetey J. , Fukuda K. , Balachandar R.
Published: September 2024

Confined jets occur in many engineering applications including combustion chambers, jet pumps, and chemical reactors. The effects of axisymmetric confinement on the vortical structures identified in a turbulent jet are investigated using large eddy simulation at a Reynolds number of 30 000 (based on nozzle exit conditions) and expansion ratio (chamber-to-nozzle diameter ratio) of five. The results obtained from the confined jet are compared with those of a free jet under the same nozzle exit flow conditions. A prominent recirculation zone forms between the expanding jet and the confining wall, resulting in early shear layer distortion and a shorter interaction length in the confined jet (0.85 jet diameters) compared to the free jet (1.15 jet diameters). Using the λ2 criterion for vortex identification, two dominant structural modes are identified in the near-exit region of the free jet: ring and helical modes. However, in the confined jet, the helical mode is absent, and the turbulent confined fluid accelerates the breakup of the ring vortices. The interaction of the secondary line vortices with the breaking structures leads to the formation of new hairpin-like vortices, which also contribute to further vortex breakup. These results explain the enhanced mixing performance of confined jets as the mixing is directly tied to the breakup of large vortical structures. Proper orthogonal decomposition modes are also presented to identify the structures/events with the highest contribution to the total turbulent kinetic energy in both flow fields.
Revisiting the strain rate sensitivity of the flow stress of copper: Theory and experiment
Authors: Yao Songlin , Yu Jidong , Pei Xiaoyang , Guo Kai , Tang Enling , Wang Guiji , Wu Qiang
Published: September 2024

One of the most important issues related to the strength of metals is the strain rate sensitivity of the flow stress. In this study, an analytical model of the flow stress as a function of strain rate is derived theoretically. The model can reproduce the strain rate sensitivity of the flow stress of copper over a wide range of strain rates (up to 109 s−1) quantitatively. Our theoretical derivations indicate that the strain rate sensitivity of the flow stress, especially that above 103 s−1, is a result of both the variation of the dislocation mobility mechanism with stress and the particular stress dependence of dislocation density but is not a result of each single mechanism. In particular, the stress dependence of the dislocation density and the initial dislocation density are critical to the quantitative relation of the flow stress–strain rate at high strain rate and the strain rate threshold, under which the upturn of the flow stress occurs, respectively. Moreover, experiments with copper of different initial dislocation densities at moderate and high strain rate are performed. The strain rate threshold of the flow stress upturn observed in the experiments grows considerably as initial dislocation density increases, which is in accordance with theoretical prediction by our model.