bluuebunny/crossref_metadata_2025 huggingface dataset:
Basic thermodynamic characteristics of toluene adsorption in Cu2+ZSM-5 Zeolite
Authors: Bakhronov Khayot , Ergashev Oybek , Esonkulova Nazirahon , Absalyamova Ilmira , Ahkmadov Majidjon
Published: August 2023

This paper presents the results of isotherms and basic (ΔH, ΔF and ΔS) thermodynamic characteristics of toluene adsorption in CuZSM-5 zeolite. For measurements of isotherms and differential heat of adsorption, a system consisting of a universal high-vacuum adsorption unit and an attached differential modified Tian-Calve microcalorimeter DAC-1-1A was used to provide direct quantitative and qualitative characteristics of the nature and forces of adsorption interaction. The correlation between the adsorption-energy characteristics wasfound and the molecular mechanismof toluene adsorption in CuZSM-5 zeolite in the whole filling region was revealed. Toluene adsorbed in CuZSM-5 zeolite is located in the first coordination sphere with Cu2+cation, forming two-dimensional complexes. It was found that the charge density significantly affects the mechanism, the energy of adsorption and the number of adsorbed molecules. It was determined that the average molar entropy of toluene adsorption in CuZSM5 zeolite indicates that the mobility of toluene molecules in zeolite is below the liquid phase and close to that of the solid phase, indicating that the mobility of toluene molecules on cations is strongly inhibited. This work shows how calorimetric data can be used to complement crystal structure results and detect subtle adsorbent/adsorbate interactions at the molecular level.
Available methods for the conversion of dichloropropane to allene and methylacetylene
Authors: Guseinova Elvira , Yusubova Sabina , Medetova Farida
Published: August 2023

. The nature of the formation of allene and methylacetylene during the dehydrochlorination of 1,2-dichloropropane and intermediate products (1-chloropropene-1, 2-chloropropene-1, 2-chloropropane, and 3-chloropropene-1) on γ-Al2O3, CaX and expanded clay made it possible to establish that the main source of allene formation on CaX and expanded clay is 2-chloropropene-1, and methylacetylene - 1-chloropropene-1, and on γ -Al2O3, allene formation appears mainly from 2-chloropropane, methylacetylene - from 2-chloroprene. The highest value of the allene: methylacetylene ratio was obtained during the dehydrochlorination of 1,2-dichloro propane and 2-chloroprene on CaX and expanded clay (6.90 and 7.30; 7.70 and 8.19, respectively), while on alumina this indicator is much lower and does not exceed 0.2, and the total the content of the allene-methylacetylene fraction in the presence of the latter is also the lowest. It is also noteworthy that, regardless of the feedstock under study, the course of the dehydrochlorination reaction in the presence of aluminum oxide is characterized mainly by the formation of methylacetylene and an insignificant formation of allene, which is probably a consequence of all methylacetylene isomerization occurring on the catalyst surface. The totality of these data made it enable to establish that the DCP conversion mechanism is carried out in different ways regarding the acid-base nature of the active sites of the catalytic systems: in the presence of γ-Al2O3 - with the participation of Lewis acid sites, and CaX and expanded clay - with the participation of Brønsted acid sites.
Improving the energy condition of the cocoon floor by modificating living and dry cocoons with surface activating substances
Authors: Sulaymonov Sh. A. , Parpiyev S. F.
Published: August 2023

In order to improve the technology of cocoon processing, to create waste-free technologies, a surface activator was synthesized on the basis of bardo residue fraction and lubricating oils formed during the production of ethyl alcohol. Based on IR-spectral analysis, the presence of hydroxyl and carboxyl groups in the synthesized surfactants was determined to be a suitable raw material for the production of surfactants, and the substance synthesized from it can be used in staining. IR-spectrum analysis shows that the valence oscillations of the hydroxyl groups belonging to the alcohols are manifested in the frequency range 3100 - 3500 cm-1. It was found out that it is possible to turn the surface into a surface activator by direct or hydrolysis in the process of cocooning from the waste of the plant “Biochemistry”. The application of the newly synthesized surface activators in the cocoon changed the surface tension that occurs in the cocoon shell. Absorbed surface activators changed the surface structure of the cocoon shell, reduced surface tension, and improved the absorption of the solution by the shell to obtain quality raw silk.
Ionic wind velocity and energy efficiency improvement in needle-net ionic wind generator by electrical field optimization
Authors: Zhang Dongxuan , Bu Fan , Zhao Yulei , Fang Zhi , Liu Feng
Published: August 2023

Ionic wind produced by high voltage discharge has been proved as a promising technique in heat dissipation, food drying, electrostatic precipitation and air propulsion. On the other hand, the low wind velocity and the low energy efficiency of the ionic wind generators limit their performance in practical industrial applications. To improve this, a single needle-net electrode structure ionic wind generator driven by positive DC voltage is constructed and the effects of the applied voltage and electrode structure on the discharge characteristics and the converting efficiency from electric energy to kinetic energy have been investigated. The results show that with the increase of the applied voltage from 4 kV to 11 kV, the discharge shows four stages, burst pulse, streamer corona, glow corona and spark discharge, and the wind velocity increases monotonously and reach 1.90 m/s at 11 kV. At the same applied voltage, the shorter needle-net distance leads to the larger wind velocity. At 15 mm needle-net distance, the needle-net electrode structure ionic wind generator shows a maximum energy efficiency value of 2.19%. A metal circular plate is attached on the needle electrode to change the spatial electric field distribution, increase the field intensity of the discharge gap, and promote the particle collision. It is found that the wind velocity and energy efficiency can be improved from 1.90 m/s to 2.35 m/s, and 1.87% to 3.14%, at same applied voltage and needle-net distance. The cooling experiment shows that the ionic wind generator with metal circular plate needle-net electrode has better heat dissipation effect.
TGF-β1 Overexpression: A Mechanism of Diastolic Filling Dysfunction in the Aged Population
Authors: Larson Douglas F. , Ingham Rene , Alwardt Cory M. , Yang Bo
Published: August 2023

The prevalence of cardiovascular disease in the United States dramatically increases with age. A hallmark feature of the aged myocardium is increased fibrosis resulting in diastolic dysfunction. Moreover, the survival of patients subsequent to a myocardial infarction is inversely related to age because of a certain extent to maladaptive remodeling mediated by cardiac fibroblasts. Our hypothesis is that cardiac fibroblast (CF) dysfunction results in overexpressed TGF-β1 leading to increased cardiac collagen content in the aged population. TGF-β1 stimulates the synthesis of the extracellular matrix proteins, including collagen in the cardiac tissues. The RT–PCR analysis of mRNA expression of TGF-β1 of the CF was increased by 43% in the aged mice as compared to the younger. The stiffness of the left ventricle is expressed with the slope of the end-diastolic pressure-volume relationship parameter, (mmHg/L). In a mouse model, we demonstrated that was 0.30 ± 0.05 in the young as compared to 0.52 ± 0.10 in the aged (p < .05). The ventricular stiffness was associated with the myocardial collagen content; namely, young versus the aged was 9.5 ± 4.0 as compared to 16.4 ± 2.3% of total protein, respectively (p < .05). In conclusion, the gene structure–function relationships support our hypothesis that cardiac fibroblast disregulation contributes to diastolic filling dysfunction in elderly persons. These data provide a potential contributory mechanism for diastolic dysfunction that may be vital in caring for the aged open-heart surgical patient.
Removal of Glucose from the Cardiopulmonary Bypass Prime: A Prospective Clinical Audit
Authors: Newland R.F. , Baker R.A. , Mazzone A.L. , Ottens J. , Sanderson A.J. , Moubarak J.R.
Published: August 2023

To quantify our decision for the removal of glucose and the use of mannitol as a substitute osmotic agent in the cardiopulmonary bypass prime, we conducted a prospective clinical audit to evaluate the effects of this change on patient outcomes. Data were prospectively collected for 172 consecutive routine cardiac surgery patients. The first 85 patients (Surgeon A, 42 patients [Group 1], Surgeon B, 43 patients [Group 2]) received 1000 mL Plasmalyte 148 + 5% glucose as per institutional protocol. The remaining priming volume for each group consisted of 500 mL hemaccel or 4% albumin, 50 mL 8.4% sodium bicarbonate, 100 mL Hartmann’s solution. The change to a glucose-free prime was then initiated, substituting Plasmalyte 148 (without 5% glucose) for the Plasmalyte 148 + 5% glucose, in addition 12.5 g mannitol was administered following delivery of cardioplegia to the patients operated on by Surgeon B. Surgeon A would not include mannitol at this time. Forty-one patients operated by Surgeon A (Group 3) subsequently received Plasmalyte 148, and 46 patients operated on by Surgeon B (Group 4) received Plasmalyte 148 plus mannitol. Analysis was performed stratified by surgeon to quantify the effects of removing glucose from the prime. Comparisons were made between groups 1 and 3, and 2 and 4. Net fluid changes were recorded from pre-CPB, up to 24-h postoperatively. Intraoperative data collection included serum glucose, hematocrit, osmolality, return to rhythm, arrhythmias, and blood transfusions. Post-operative variables, including cardiac enzymes, arrhythmias, intubation time, length of stay, and mortality were also collected. Removal of glucose from the CPB prime resulted in a lower serum glucose concentration (mmol/L) during CPB (Gp 1 [13.6] vs. Gp 3 [5.4]; Gp 2 [14.7] vs. Gp 4 [5.4], p < .05). The addition of 12.5 g of mannitol to the CPB prime resulted in a significantly lower net fluid gain (mL) 24 h postoperatively (Gp 2[2792] vs. Gp 4 [1970], p < .05) and greater CPB hematocrit (%) (Gp 2 [24.3] vs. Gp 4 [26], p < .05). No other results were found to be significant (except CPB plasma osmolality (Groups 2 and 4) and sodium concentration [Groups 1 and 3]). The results of our audit provide an evidence base to support our change in practice to utilize nonglucose primes.
The Hemochron® Response RxDx® Heparin and Protamine Dosing System
Authors: Jaryno Stacy A. , Zucker Marcia L. , LaDuca Frank M.
Published: August 2023

The use of dosing assays to calculate heparin and protamine dose requirements during cardiac surgery has been shown to significantly improve overall postoperative patient outcome. When patients are managed with an individualized dosing system, intraoperative and postoperative transfusion requirements and bleeding are reduced. The Hemochron® RxDx® system is widely used as a complement to traditional activated clotting time testing to optimize anticoagulation management. The system consists of the heparin response test, the protamine response test, and the protamine dose assay. All are modifications of the activated clotting time using either Celite® (Celite Corporation, Santa Barbara, CA) or kaolin as the activator. Dosing is calculated manually using earlier version Hemochron instruments (model 801) or automatically with the Hemochron 8000 or with the early versions of the Hemochron® Response and the personal digital assistant (PDA) RxDx calculator. Missing from available user options is an automated RxDx system for the Response. A study was conducted at four clinical sites to compare recently developed Response RxDx software, which eliminates the need for the PDA RxDx calculator, to the existing Hemochron 8000 RxDx and to the Response-PDA RxDx systems. Similar to the current system, the operator inputs the patient’s height, weight, and gender, and the software automatically calculates the blood volume. Using the clotting times determined on the Response, bolus heparin and protamine doses and any additional heparin and protamine requirements are calculated automatically. Data were collected from 76 patients, of which, 64 patients were on pump, 11 patients were off pump, and 1 patient was converted from off to on pump. The Response estimated blood volume calculations showed a correlation coefficient of 0.989 when compared with available systems. A good correlation was also observed for the bolus heparin (r = 0.925) and protamine doses (r = 0.900) with equivalence confirmed by a paired student’s t test. These data confirm that the Response RxDx system yields results that are identical (P > 0.05) to those obtained using the Hemochron 8000 RxDx or Response-PDA RxDx calculator. The Response RxDx also offers expanded user options related to blood volume limits, expanded clotting time ranges for presetting default values, and flexibility in test sequence. Case records can be printed or downloaded to a PC via the HRDM data management program. The Hemochron Response RxDx represents a complete anticoagulation management system for the cardiac surgical patient.
Cardiopulmonary Bypass: It’s Not the Size, It’s How You Use It! Review of a Comprehensive Blood-Conservation Strategy
Authors: Lilly Kevin J. , O’Gara Paul J. , Treanor Patrick R. , Reardon Deborah , Crowley Richard , Hunter Curtis , Shapira Oz M. , Aldea Gabriel S. , Lazar Harold L. , Shemin Richard J.
Published: August 2023

Several of the manufacturers of cardiopulmonary bypass equipment have recently introduced new miniature cardiopulmonary bypass systems. New advancements in cardiopulmonary bypass technology are almost always of interest to the perfusion community. However, the question arises, what advantages do these systems offer over our present technology? The manufacturers claim that these new systems will add to our perfusion armamentarium by offering us an opportunity to further reduce priming volume and the surface area to which the blood is exposed. Our group, in the Department of Cardiac Surgery at Boston Medical Center has been involved in the development of a comprehensive blood conservation strategy since 1994. Our published data clearly demonstrates improved clinical outcomes using coated circuit technology as part of a comprehensive blood conservation strategy. In an effort to clearly evaluate this new technology, in this article we review our current technique at Boston Medical Center.
Dossier « Recherches sur la question animale : entre mobilisations sociétales et innovations technologiques » – Contributions des technologies de précision pour améliorer les conditions de travail dans les élevages agroécologiques : questionnements et perspectives
Authors: Hostiou Nathalie , Jeanneaux Philippe , Duval Julie , Lebrun Manon , Nowak Benjamin
Published: August 2023

Cet article analyse la contribution potentielle de l’élevage de précision à l’amélioration des conditions de travail des éleveurs engagés dans une démarche de transition agroécologique. L’agroécologie ne conduit pas forcément à de meilleures conditions de travail (temps de travaux, complexité et charge mentale, savoirs). Les technologies de précision pourraient aider à la transition agroécologique des élevages en réduisant les charges de travail, en donnant plus de souplesse dans les horaires ou encore en aidant à la gestion de situations complexes. Cependant, pour d’autres dimensions du travail à enjeux pour la transition agroécologique – l’autonomie décisionnelle, le rapport aux animaux et à la nature –, des réserves et des questionnements subsistent. Nous concluons que plus que les fondements de l’agroécologie et de l’élevage de précision, parfois antagonistes, parfois complémentaires, c’est bien la façon dont les éleveurs vivent leur travail qui sera important à prendre en compte pour que les technologies du numérique soit un réel support à la transition agroécologique.
Progresses of the international community to understand sunflower–pollinator interactions through multiscale approaches
Authors: Catrice Olivier , Holalu Srinidhi , Terzić Sreten , Todesco Marco , Creux Nicole , Langlade Nicolas B.
Published: August 2023

The first web conference on sunflower–pollinator interactions gathered the international community around a major topic for sunflower productivity and ecosystemic biodiversity. Insect-mediated pollination is important for increasing sunflower seed yield, but is dependent on environmental factors. Climate change can impact sunflower-pollinator interactions by influencing both plant and pollinator behavior. Natural or artificially elevated ambient temperatures appear to accelerate floret development and advance the timing of pollen presentation to coincide with pollinator activities. Drought showed no major effect on morphological traits such anther or corolla length, but dramatically reduced nectar and pollen productions. Flavonol-glycoside conjugates lower head transpiration thereby mitigating deleterious effects of abiotic stresses. Wild pollinators show fine scale preferences among sunflower varieties, likely due to the different resource focus of wild and managed honeybees. Agricultural practices such as planting flower strips to provide nesting sites for wild pollinators, or supplementing crop plots with hives, can have a positive effect on insect-mediated pollination efficiency and ensure optimal yields. All together, recent results on sunflower–pollinator interactions pave the way to develop varieties and corresponding cropping systems more favorable to pollinator biodiversity while maintaining high yields in the context of climate change.
Analgesic Efficacy of Foot and Hand Massage for Laparoscopic
Cholecystectomy: A Meta-Analysis
Authors: Chen Jia , Zhang Piyun , Wei Yuanxiu , Zhou Li , Xiao Xiao , Wan Xiaoqiang
Published: August 2023

Background Foot and hand massage may benefit to alleviate pain for
laparoscopic cholecystectomy, and this meta-analysis is intended to study the
influence of foot and hand massage on pain intensity after laparoscopic
cholecystectomy.

Methods We systematically searched PubMed, EMbase, Web of science, EBSCO,
and Cochrane library databases, and included randomized controlled trials (RCTs)
assessing the effect of foot and hand massage on postoperative pain of
laparoscopic cholecystectomy.

Results Six RCTs and 663 patients were included in the meta-analysis.
Compared with control intervention for laparoscopic cholecystectomy, massage
intervention resulted in significantly decreased pain scores at 60 min
(SMD=–0.73; 95% CI=–1.27 to
–0.19; P=0.008), pain scores at 90 min
(SMD=–0.80; 95% CI=–1.23 to
–0.37; P=0.0003), pain scores at 120–150 min
(SMD=–1.74; 95% CI=–1.96 to
–1.52; P<0.00001) and the need of additional analgesia
(OR=0.04; 95% CI=0.02 to 0.07; P<0.00001), but
demonstrated no influence on pain scores at 10–30 min
(SMD=–0.14; 95% CI=–0.39 to 0.12;
P=0.29).

Conclusions Foot and hand massage may be able to reduce pain intensity
after laparoscopic cholecystectomy.
Effect of Internalized Stigma on Peer Relationships in Adolescents with Attention-Deficit/Hyperactivity Disorder
Authors: Üşenmez Tülay Yildirim , Durmaz Gülbeyaz Baran , Budak Funda Kavak
Published: August 2023

This study aimed to determine the effect of internalized stigma on peer relationships in adolescents with attention-deficit/hyperactivity disorder (ADHD). The study was conducted in a Special Education and Rehabilitation Center between August and September 2022. The correlational and cross-sectional study sample consisted of 70 adolescents with ADHD. The Descriptive Characteristics Form, the Internalized Stigma Scale for Children and Adolescents, and the Peer Relationship Scale were used to collect the data. It was determined that the mean total score of internalized stigma levels of adolescents was 93.24 (16.16), and the mean total score of peer relationships was 53.78 (10.76). It was determined that there was a strong negative correlation between the total score of internalized stigma and peer relationships (r = − 0.748, p = 0.001). In addition, it was determined that internalized stigma predicted peer relationships by 55%. It can be said that internalized stigma and peer relationships of adolescents are moderate, and as adolescents' internalized stigma levels increased, their peer relationships decreased.
The Random Pattern De-Epithelialized Turn Over Flap
Authors: Bhatnagar S. K. , Pandey Arun K. , Kumar Pramod , Sahi R. P. , Singh O. P. , Kalra G. S.
Published: August 2023

Random pattern de-epithelialized flap has been used in 23 cases as resurfacing procedure and its scope has been evaluated in elective as well as in emergency situations.
A New Method for Covering Defects over Forearm with Extern Al Fixator Apparatus in Position
Authors: Pathil D. L. , Kumta S. M. , Thatte R. L.
Published: August 2023

A case of a mutilating injury of the forearm treated with a multiple entry A. O. external fixator was provided with a flap cover from the abdomen. The manoeuvre used to achieve the flap cover, along with a brief discussion is being presented.
Unilateral Hypertrophic Male Nipple
Authors: Khanna A. K. , Mishra M. K.
Published: August 2023

A male patient with unilateral hypertrophy of the right nipple, an extremely rare clinical entity is being described.
Smart epidermal electrophysiological electrodes: Materials, structures, and algorithms
Authors: Ye Yuanming , Wang Haochao , Tian Yanqiu , Gao Kunpeng , Wang Minghao , Wang Xuanqi , Liang Zekai , You Xiaoli , Gao Shan , Shao Dian , Ji Bowen
Published: August 2023

Epidermal electrophysiological monitoring has garnered significant attention for its potential in medical diagnosis and healthcare, particularly in continuous signal recording. However, simultaneously satisfying skin compliance, mechanical properties, environmental adaptation, and biocompatibility to avoid signal attenuation and motion artifacts is challenging, and accurate physiological feature extraction necessitates effective signal-processing algorithms. This review presents the latest advancements in smart electrodes for epidermal electrophysiological monitoring, focusing on materials, structures, and algorithms. First, smart materials incorporating self-adhesion, self-healing, and self-sensing functions offer promising solutions for long-term monitoring. Second, smart meso-structures, together with micro/nanostructures endowed the electrodes with self-adaption and multifunctionality. Third, intelligent algorithms give smart electrodes a “soul,” facilitating faster and more-accurate identification of required information via automatic processing of collected electrical signals. Finally, the existing challenges and future opportunities for developing smart electrodes are discussed. Recognized as a crucial direction for next-generation epidermal electrodes, intelligence holds the potential for extensive, effective, and transformative applications in the future.
Solitonic-like interactions of counter-propagating clusters of active particles
Authors: Escaff Daniel
Published: August 2023

This report considers a set of interacting self-propelled particles immersed in a viscous and noisy environment. The explored particle interaction does not distinguish between alignments and anti-alignments of the self-propulsion forces. More specifically, we considered a set of self-propelled apolar aligning attractive particles. Consequently, there is no genuine flocking transition because the system has no global velocity polarization. Instead, another self-organized motion emerges, where the system forms two counter-propagating flocks. This tendency leads to the formation of two counter-propagating clusters for short-range interaction. Depending on the parameters, these clusters interact, exhibiting two of the four classical behaviors of counter-propagating dissipative solitons (which does not imply that a single cluster must be recognized as a soliton). They interpenetrate and continue their movement after colliding or forming a bound state where the clusters remain together. This phenomenon is analyzed using two mean-field strategies: an all-to-all interaction that predicts the formation of the two counter-propagating flocks and a noiseless approximation for cluster-to-cluster interaction, which explains the solitonic-like behaviors. Furthermore, the last approach shows that the bound states are metastables. Both approaches agree with direct numerical simulations of the active-particle ensemble.
Synchronization of uncertain general fractional unified chaotic systems via finite-time adaptive sliding mode control
Authors: Fu Hui , Kao Yonggui
Published: August 2023

This paper employs two adaptive sliding mode control (ASMC) strategies to accomplish finite-time synchronization of uncertain general fractional unified chaotic systems (UGFUCSs) when uncertainty and external disturbance exist. First, general fractional unified chaotic system (GFUCS) is developed. GFUCS may be transitioned from general Lorenz system to general Chen system, and the general kernel function could compress and extend the time domain. Furthermore, two ASMC methods are applied to finite-time synchronization of UGFUCSs, where system states arrive at sliding surfaces in finite-time. The first ASMC approach utilizes three sliding mode controllers to achieve synchronization between chaotic systems, while the second ASMC method needs just one sliding mode controller to produce synchronization between chaotic systems. Finally, the effectiveness of the proposed ASMC approaches is verified using numerical simulations.
Recent advances in silicon-based nanostructures for thermoelectric applications
Authors: Sojo Gordillo Jose Manuel , Morata Alex , Sierra Carolina Duque , Salleras Marc , Fonseca Luis , Tarancón Albert
Published: August 2023

In this work, implementations of silicon-based thermoelectric nanomaterials are reviewed. Approaches ranging from nanostructured bulk—i.e., macroscopic materials presenting nanoscale features—to more complex low-dimensional materials are covered. These implementations take advantage of different phonon scattering mechanisms and eventual modifications of the electronic band-structure for the enhancement of the thermoelectric figure of merit. This work is focused on the recent advances in silicon and silicon-based thermoelectric nanomaterials of the last decade—at both the theoretical and experimental level—with the spotlight on the most recent works. Different nanostructures and their fabrication methods are detailed, while the thermoelectric performances and the feasibility of their integration into functional micro-harvester generators are compared and discussed. This Research Update first covers the advances in nanostructured bulk, such as nanometric-sized polycrystals or defect-induced materials. Subsequently, it reviews low-dimensional materials, namely, thin films and nanowires. Later, other complex structures based on nanoporosity, superlattices, or core–shell schemes are detailed. Finally, it is devoted to present examples of the successful implementation of nanostructured silicon into functional thermoelectric devices.
Lévy noise influences basin stability in a delayed vegetation-water dynamical system
Authors: Zhang Hongxia , Song Yi
Published: August 2023

The stochastic stability for the irregular attraction basin in a time-delayed vegetation-water ecosystem disturbed by Lévy noise is explored. We first discuss that average delay time does not change the attractors of the deterministic model but affects the corresponding attraction basins, and we present the generation of Lévy noise. Then, we investigate the influence of stochastic parameters and delay time on the ecosystem by two statistical indicators, the first escape probability (FEP) and the mean first exit time (MFET). The numerical algorithm for calculating the FEP and the MFET in the irregular attraction basin is implemented, which is effectively verified by Monte Carlo simulations. Furthermore, the metastable basin is defined by the FEP and the MFET and confirms the consistency of the two indicators reflecting results. The result shows that the stochastic stability parameter, especially the noise intensity, decreases the basin stability of the vegetation biomass. In this environment, the time delay effect can validly alleviate its instability.
Evolution of tsunami-like isolated waves shoaling over a plane slope
Authors: Knowles Jeffrey , Yeh Harry
Published: August 2023

Numerical experiments are conducted to simulate Gaussian-shaped waves shoaling over a uniformly sloping bed. A higher-order pseudo-spectral method is implemented to solve the fully nonlinear Euler water-wave problem for a variable depth. Unlike a solitary wave, the amplitude and wave breadth of a Gaussian waveform can be assigned independently. Therefore, it is convenient to use a Gaussian as a generic tsunami waveform. Although the rate of shoaling is consistent with Green's law only for small-amplitude waves propagating over intermediate sloping beds, the shoaling processes, in general, are complex and the behaviors cannot be accurately predicted by a single law. Several factors are involved in the complexity. When the slope is sufficiently mild, a Gaussian wave transforms into a series of solitons, hence leading to the adiabatic shoaling process. In some instances, the initial rate of shoaling even surpasses the adiabatic rate. This occurs when a soliton emerges from the initial conditions with an amplitude greater than the original Gaussian wave amplitude. In general, there is a trend of a faster shoaling rate when the nonlinearity effect of the Gaussian is greater than that of the corresponding solitary wave, whereas the rate of shoaling for Gaussian waves is slower when the frequency dispersion is greater than that of the solitary wave. The model is further applied to simulate the 2011 Heisei tsunami event, and the shoaling behavior is analyzed by comparing the numerical results with the recorded data in the field.
Viscosity of finite Yukawa liquids
Authors: Liu Yang , Blosczyk Natascha , Block Dietmar
Published: August 2023

The shear viscosity of a finite two-dimensional (2D) Yukawa liquid is calculated using non-equilibrium Langevin simulations. Two counter-propagating shear forces are used to push the particles and cause shear-induced melting of the cluster. The melting temperature of the 2D cluster system is used to derive the effective coupling parameter Γ * of this finite system and allows us to investigate the relationship between shear viscosity and system properties Γ * and κ. The simulation data shows that the value of the shear viscosity rises for coupling parameters Γ * > 20 and follows a simple universal scaling for appropriate normalization. It is further found that the Green–Kubo relation is applicable to determine viscosity in finite non-equilibrium systems with Γ * < 80.
DC conductivity mechanism in La0.7Sr0.3MnO3 (LSMO)-ZnO nanocomposites
Authors: Chatterjee Sumon , Labar Rini , Nooruddin Mehbub A. K. , Roy Subhasish , Kundu Tapas Kumar
Published: August 2023

La0.7Sr0.3MnO3 (LSMO)-ZnO nanocomposites with varying concentrations of ZnO have been synthesized using the solution combustion method. A bimodal particle size distribution has been formed in all the samples. The crystallite size increases in the composites as compared to LSMO. The study on electrical resistivity reveals that LSMO exhibits a metal-to-insulator transition at 359 K, while the inclusion of ZnO suppresses the metallic behavior in the composites and increases the resistivity. Transport behavior of the samples in metallic and semiconducting regions has been explained with a known polynomial equation and a two-channel conduction model obeying the small polaron hopping mechanism, respectively. A very low activation energy in the range of 10–12 meV is observed due to smaller-sized particles. The presence of ZnO drives the hopping mechanism from adiabatic in LSMO to become non-adiabatic in the composites and enhances the maximum temperature coefficient of resistance. 80% LSMO-20% ZnO (by weight ratio) composite shows a maximum TCR of −29.81%/K at 248 K, which makes it a potential candidate for several applications in sensing devices. The Curie temperature of the material decreases with the increase in ZnO content in the sample. The results of this study also confirm the existence of correlation between the electrical and magnetic properties of LSMO.
Ultrathin copper films grown on SrTiO3 substrates for epitaxy of single-crystalline γ-FeMn
Authors: Li Xiaolin , Liu Xu , Li Hang , Lü Ying-Qi , Gao Cunxu
Published: August 2023

The topological antiferromagnet γ-FeMn is a fascinating material for studying unconventional magnetic properties and topological transport phenomena though high-quality γ-FeMn has been obtained on the Cu substrate for magnetic research. However, the difficulty of growing single-crystalline γ-FeMn films on insulating substrates has prevented experiments from exactly verifying many theoretical predictions on their transport properties. Ultrathin Cu buffer films have been considered for solving this problem but failed because the crystal quality and thickness of Cu films achieved in previous works do not satisfy the growth buffer criteria for γ-FeMn. In this work, the growth of 5-nm-thick Cu films on SrTiO3(001) substrates was studied. It was found that single-crystalline ultrathin Cu films with roughness as low as 1 nm are obtained on the insulating substrate. We subsequently obtained high crystalline quality γ-FeMn films with smooth surface and verified their antiferromagnetism. Finally, two aspects of the influence of Cu films on adjacent films have been analyzed. Our results facilitate the experimental exploration of the fascinating properties of γ-FeMn.
Electron energy dissipation in a magnetotail reconnection region
Authors: Burch J. L. , Genestreti K. J. , Heuer S. V. , Chasapis A. , Torbert R. B. , Gershman D. J. , Bandyopadhyay R. , Pollock C. J. , Matthaeus W. H. , Nakamura T. K. M. , Egedal J.
Published: August 2023

The four Magnetospheric Multiscale spacecraft encountered a reconnection region in the Earth's magnetospheric tail on 11 July 2017. Previous publications have reported characteristics of the electron diffusion region, including its aspect ratio, the reconnection electric field, plasma wave generation from electron beams in its vicinity, and energetic particles in the Earthward exhaust. This paper reports on the investigation of conversion of electromagnetic energy to electron kinetic energy (by J·E) and the ensuing conversion of electron beam energy to electron thermal energy via the pressure–strain interaction. The main result is that omnidirectional, compressive dissipation of electron energy dominates in the positive J·E region, while incompressive parallel dissipation dominates in the inflow region where J·E is small. The existence of parallel electric fields in the inflow region supports previous suggestions that electron trapping by these fields contributes to the parallel dissipation. All of the results are reproduced quantitatively within a factor of two with a 2.5-D particle-in-cell simulation.
Direct differentiation of human pluripotent stem cells into vascular network along with supporting mural cells
Authors: Bertucci Taylor , Kakarla Shravani , Winkelman Max A. , Lane Keith , Stevens Katherine , Lotz Steven , Grath Alexander , James Daylon , Temple Sally , Dai Guohao
Published: August 2023

During embryonic development, endothelial cells (ECs) undergo vasculogenesis to form a primitive plexus and assemble into networks comprised of mural cell-stabilized vessels with molecularly distinct artery and vein signatures. This organized vasculature is established prior to the initiation of blood flow and depends on a sequence of complex signaling events elucidated primarily in animal models, but less studied and understood in humans. Here, we have developed a simple vascular differentiation protocol for human pluripotent stem cells that generates ECs, pericytes, and smooth muscle cells simultaneously. When this protocol is applied in a 3D hydrogel, we demonstrate that it recapitulates the dynamic processes of early human vessel formation, including acquisition of distinct arterial and venous fates, resulting in a vasculogenesis angiogenesis model plexus (VAMP). The VAMP captures the major stages of vasculogenesis, angiogenesis, and vascular network formation and is a simple, rapid, scalable model system for studying early human vascular development in vitro.
Fast evaluation of spherical harmonics with sphericart
Authors: Bigi Filippo , Fraux Guillaume , Browning Nicholas J. , Ceriotti Michele
Published: August 2023

Spherical harmonics provide a smooth, orthogonal, and symmetry-adapted basis to expand functions on a sphere, and they are used routinely in physical and theoretical chemistry as well as in different fields of science and technology, from geology and atmospheric sciences to signal processing and computer graphics. More recently, they have become a key component of rotationally equivariant models in geometric machine learning, including applications to atomic-scale modeling of molecules and materials. We present an elegant and efficient algorithm for the evaluation of the real-valued spherical harmonics. Our construction features many of the desirable properties of existing schemes and allows us to compute Cartesian derivatives in a numerically stable and computationally efficient manner. To facilitate usage, we implement this algorithm in sphericart, a fast C++ library that also provides C bindings, a Python API, and a PyTorch implementation that includes a GPU kernel.
Radiation intensity dependence of CdSe photothermal and photocarrier radiometry response evidenced by step-sine modulation method
Authors: Chirtoc M. , Pawlak M. , Horny N.
Published: August 2023

The radiation intensity dependence of photothermal (PT) and photocarrier (PC) signals from n-type CdSe single crystals was investigated by modulated infrared radiometry (MIRR) in the mid-IR range (5–11.3 μm) with superbandgap photoexcitation. The influence of dc temperature increase of the sample was avoided by a new step-sine modulation method that combines the advantages of transient and periodical modulation. With increasing laser intensity I, the amplitude of the PC component shows a sub-linear dependence (|SPC| ∝ I0.5), while the PT one has the expected linear dependence (|SPT| ∝ I). As a result, the transition frequency ft between the two components is shifted to higher frequencies, which is explained in the frame of a simple model. The origin of the observed effects is the decrease of the effective photocarrier lifetime τ ∝ I−0.5 over three laser intensity decades. In contrast, previous studies on nonlinear PC response in semiconductors performed in the near-IR range (0.7–1.8 μm) have found supra-linear |SPC| dependence with exponent between 1 and 2. This difference is attributed to the fact that the near-IR radiometric signal features characteristics of a photoluminescence (PL) signal that are different from those of the mid-IR PC signal, as shown in our previous study [J. Appl. Phys. 119, 125108 (2016)] on the same CdSe samples.
Abrupt Te doping of GaInP grown by molecular beam epitaxy for solar cell applications
Authors: Li Brian , Sun Yukun , Hool Ryan D. , Lee Minjoo Larry
Published: August 2023

We report abrupt Te doping of GaInP solar cells grown by molecular beam epitaxy (MBE) through the use of a low substrate temperature of 420 °C and subsequent elimination of surface segregation. First, a Te surface pre-dose layer and reduced substrate temperature were required to achieve abrupt profiles at doping >1 × 1018 cm−3 in calibration samples, while reduced doping of 5.7 × 1017 cm−3 did not require the surface layer. Next, we demonstrate front-junction n+/p GaInP cells with an improved internal quantum efficiency (IQE) after Te doping of the n-type emitter directly attributable to an ∼2.5× higher carrier diffusion length, with IQE-derived short-circuit current density increasing from 13.2 to 14.1 mA/cm2. Rapid thermal annealing further boosted the performance through improvements in the minority carrier lifetime of the p-GaInP base. The use of low substrate temperature in MBE-grown GaInP enables abrupt Te doping profiles to be attained in a straightforward manner and is promising for both solar cells and tunnel junctions.
A perspective on the pathway to a scalable quantum internet using rare-earth ions
Authors: Pettit Robert M. , Farshi Farhang Hadad , Sullivan Sean E. , Véliz-Osorio Álvaro , Singh Manish Kumar
Published: August 2023

The ultimate realization of a global quantum internet will require advances in scalable technologies capable of generating, storing, and manipulating quantum information. The essential devices that will perform these tasks in a quantum network are quantum repeaters, which will enable the long-range distribution of entanglement between distant network nodes. In this review, we provide an overview of the primary functions of a quantum repeater and discuss progress that has been made toward the development of repeaters with rare-earth ion doped materials while noting challenges that are being faced as the technologies mature. We give particular attention to erbium, which is well suited for networking applications. Finally, we provide a discussion of near-term benchmarks that can further guide rare-earth ion platforms for impact in near-term quantum networks.
Qualitative and quantitative analysis of interaction between cavitation patterns and vortices of a pitching hydrofoil from Lagrangian viewpoint
Authors: Jia Ruidong , Chen Zhizhe , Chai Lianjie , Zhang Jiazhong , Deguchi Yoshihiro , Li Zhihui
Published: August 2023

The evolution of transient flow structures and mass transport in cavitating flow around a pitching hydrofoil is investigated qualitatively and quantitatively, and the interaction between cavitation patterns and vortices is elucidated from Lagrangian viewpoint. First, turbulence effects are estimated by the density-corrected k–ω model to account for the local compressibility of the multiphase flow at Reynolds number Re=6.4×105. Then, the formation and evolution of vorticity structures during the whole pitching cycle are analyzed using Lagrangian averaged vorticity deviation method. By comparing the flow structures and hydrodynamic properties at varying angles of attack, the cavitating flow is divided into two distinct stages, namely multi-scale cloud cavitation phase from α+=10° to α−=8°, and traveling sheet cavitation phase from α−=8° to α+=10°. Specifically in cloud cavitation, the formation of the cavitation pattern is closely related to the development of the main vortex. Furthermore, the quantitative analysis method based on Lagrangian flow network is developed to deeply analyze the transport and mixing processes. Importantly, the coherence ratio and the mixing parameter are proposed as transport indicators to precisely quantify the spatial connectivity behavior. Finally, the correlations between vapor fraction, codelength, global coherence ratio and global mixing parameter are evaluated. As the conclusion, it is shown that Lagrangian methods are powerful tool for both qualitative and quantitative analysis, and the results obtained could provide a key and important understanding of the flow structure and changing mechanism between cavitation and vortices in marine hydro and propulsion systems.
Influence of frequency on the partial discharge characteristics of biaxially oriented polypropylene film under nanosecond pulse voltage
Authors: Mi Yan , Chen Yong , Liu Canhui , Zhu Yakui , Liu Wentao , Peng Yiqin
Published: August 2023

Partial discharge (PD) is one of the key factors leading to premature insulation failure of film capacitors used in pulse power devices. To study the effect of frequency on the PD characteristics of biaxially oriented polypropylene (BOPP) film, a sphere-plate electrode was used to simulate defects of the air gap between the film layers. PD experiments of the BOPP film were carried out under 1, 10, 100, 500 Hz, and 1 kHz with a rising edge of 65 ns and a pulse width of 300 ns. The results show that the repetitive partial discharge inception voltage (RPDIV), the number of discharges, the rising stage discharge (RSD) amplitude, and the falling stage discharge (FSD) time-lag, all show an increase and then decrease with increasing pulse frequencies and reach a maximum value at a pulse frequency of 100 Hz. Moreover, the FSD discharge amplitude and the RSD discharge time-lag increase with an increasing pulse frequency. From the perspective of initial electron generation, the quantitative mathematical relationship between PD characteristics (RPDIV, PD amplitude, PD number, and PD time-lag) and frequency was established based on the Fowler–Nordheim field emission effect for the first time, which can reflect the influence of frequency on the memory effect and the development process of PD. The results can provide an experimental basis and a mechanistic explanation for the evaluation of PD characteristics for film capacitors under nanosecond pulse voltage.
Discharge of liquid and grains from a silo with multiple orifices
Authors: Rodríguez-López D. , Pacheco-Sósol F. C. , Elizondo-Aguilera L. F. , Pacheco-Vázquez F.
Published: August 2023

Using a multi-orifice cylindrical silo, the average flow rates Q1 and QN through one and N orifices, respectively, were first measured for the discharge of water or dry grains and then for the mixture. As expected, QN=NQ1 for monophasic discharges. Nevertheless, for the mixture, QN≪NQ1, and the effect becomes more notorious as N augments and when the grain size is decreased. A simplified continuum model of a flow through a dynamic porous medium, with hydrodynamic resistance that increases with N, is used to reproduce the experimental results. Additional analysis in a two-dimensional cell reveals interacting parabolic flow profiles of the immersed particles close to the orifices, with a reduction in the average velocities when N is increased, which helps to understand the non-additivity of the total flow rate.
Exploring energy landscapes for solid-state systems with variable cells at the extended tight-binding level
Authors: Pracht Philipp , Morgan John W. R. , Wales David J.
Published: August 2023

The design of novel materials requires a theoretical understanding of dynamical processes in the solid state, including polymorphic transitions and associated pathways. The organization of the potential energy landscape plays a crucial role in such processes, which may involve changes in the periodic boundaries. This study reports the implementation of a general framework for periodic condensed matter systems in our energy landscape analysis software, allowing for variation in both the unit cell and atomic positions. This implementation provides access to basin-hopping global optimization, the doubly nudged elastic band procedure for identifying transition state candidates, the missing connection approach for multi-step pathways, and general tools for the construction and analysis of kinetic transition networks. The computational efficacy of the procedures is explored using the state-of-the-art semiempirical method GFN1-xTB for the first time in this solid-state context. We investigate the effectiveness of this level of theory by characterizing the potential energy and enthalpy landscapes of several systems, including silicon, CdSe, ZnS, and NaCl, and discuss further technical challenges, such as translational permutation of the cell. Despite the expected limitations of the semiempirical method, we find that the resulting energy landscapes provide useful insight into solid-state simulations, which will facilitate detailed analysis of processes such as defect and ion migration, including refinement at higher levels of theory.