bluuebunny/crossref_metadata_2025 huggingface dataset:
Ultrasound as a Sole Modality for Prenatal Diagnosis of Placenta Accreta Spectrum: Potentialities and Pitfalls
Authors: Gulati Anshika , Anand Rama , Aggarwal Kiran , Agarwal Shilpi , Tomer Shaili
Published: October 2021

Background Placenta accreta spectrum (PAS) is a significant cause of maternal and neonatal mortality and morbidity. Its prevalence has been rising considerably, primarily due to the increasing rate of primary and repeat cesarean sections. Accurate prenatal identification of PAS allows optimal management because the timing of delivery, availability of blood products, and recruitment of skilled anesthesia, and surgical team can be arranged in advance.

Aims and Objectives This study aimed to (1) study the ultrasound and color Doppler features of PAS, (2) correlate imaging findings with clinical and per-operative/histopathological findings, and (3) evaluate the accuracy of ultrasound for the diagnosis of PAS in patients with previous cesarean section.

Materials and Methods This prospective study was conducted in radiology department of a tertiary care hospital. After screening 1,200 pregnant patients, 50 patients of placenta previa with period of gestation ≥ 24 weeks and history of at least one prior cesarean section were included in the study. Following imaging features were evaluated: (1) gray scale covering intraplacental lacunae, disruption of uterovesical interface, myometrial thinning, loss of retroplacental clear space, and focal exophytic masses; and (2) color Doppler covering intraplacental lacunar flow, hypervascularity of uterine serosa–bladder wall interface, and perpendicular bridging vessels between placenta and myometrium.

Study Design Present study is a prospective one in a tertiary care hospital.

Results Of the 19 PAS cases, 18 were correctly diagnosed on ultrasonography (USG) and confirmed either by histopathological analysis of hysterectomy specimen or per-operatively due to difficulty in placental removal. PAS was correctly ruled out in 27 of 31 patients. The diagnostic accuracy of USG was 90%. The sensitivity, specificity, positive, and negative predictive values were 94.7, 87.1, 81.8, and 96.4%, respectively.

Conclusion Ultrasound is indispensable for the evaluation of pregnant patients. It is an important tool for diagnosing PAS, thereby making the operating team more cautious and better equipped for difficult surgery and critical postoperative care. It can be relied upon as the sole modality to accurately rule out PAS in negative patients, thereby obviating unnecessary psychological stress among patients due to possible hysterectomy.
Comparison of PLANE Technique versus Standard Echocardiography Guidance for Pediatric Pericardiocentesis
Authors: Clark Stephen T. , Alten Jeffrey A. , Borasino Santiago , Hock Kristal M. , Law Mark A.
Published: October 2021

Percutaneous pericardiocentesis remains a challenging and potentially dangerous procedure, particularly in small, critically ill patients. We present outcomes of the PLANE (pericardiocentesis using long-axis in-plane real-time echocardiography) technique for pediatric pericardiocentesis compared with a standard echocardiography (ECHO) guidance cohort. This was a retrospective chart review of all children undergoing percutaneous pericardiocentesis from March 2013 to February 2021 at a single center. A total of 78 procedures were performed, 52 utilizing PLANE technique and 26 utilizing standard ECHO-guidance technique. There was 100% technical success rate with only one minor complication for the entire cohort. Procedures were evenly split between the bedside intensive care unit and cardiac catheterization laboratory. PLANE technique was utilized in significantly younger (1.4 vs. 8.4 years, p = 0.008) and smaller (11.1 vs. 31.8 kg, p = 0.007) patients, as well as in most patients deemed high risk (postoperative < 7 days, extracorporeal membrane oxygenation (ECMO) support, and/or weight less than 5 kg; 19/22, p = 0.021). Other patient characteristics were similar between the two groups. There was a trend toward PLANE technique utilization by noncardiology trained operators. The PLANE technique for pediatric pericardiocentesis is safe and effective and can be effectively utilized in small and high-risk patient populations. The technical similarity to other long-axis ultrasound-guided procedures may facilitate adoption and mastery by critical care trained operators.
Before-Visit Questionnaire: A Tool to Augment Communication and Decrease Provider Documentation Burden in Pediatric Diabetes
Authors: Kumah-Crystal Yaa A. , Stein Preston M. , Chen Qingxia , Lehmann Christoph U. , Novak Laurie L. , Roth Sydney , Rosenbloom S. Trent
Published: October 2021

Objective To develop and evaluate an electronic tool that collects interval history and incorporates it into a provider summary note.

Methods A parent-facing online before-visit questionnaire (BVQ) collected information from parents and caregivers of pediatric diabetes patients prior to a clinic encounter. This information was related to interval history and perceived self-management barriers. The BVQ generated a summary note that providers could paste in their own documentation. Parents also completed postvisit experience questionnaires. We assessed the BVQs perceived usefulness to parents and providers and compared provider documentation content and length pre- and post-BVQ rollout. We interviewed providers regarding their experiences with the system-generated note.

Results Seventy-three parents of diabetic children were recruited and completed the BVQ. A total of 79% of parents stated that the BVQ helped with visit preparation and 80% said it improved perceived quality of visits. All 16 participating providers reviewed BVQs prior to patient encounters and 100% considered the summary beneficial. Most providers (81%) desired summaries less than 1 week old. A total of 69% of providers preferred the prose version of the summary; however, 75% also viewed the bulleted version as preferable for provider review. Analysis of provider notes revealed that BVQs increased provider documentation of patients' adherence and barriers. We observed a 50% reduction in typing by providers to document interval histories. Providers not using summaries typed an average of 137 words (standard deviation [SD]: 74) to document interval history compared with 68 words [SD 47] typed with BVQ use.

Discussion Providers and parents of children with diabetes appreciated the use of previsit, parent-completed BVQs that automatically produced provider documentation. Despite the BVQ redistributing work from providers to parents, its use was acceptable to both groups.

Conclusion Parent-completed questionnaires on the patient's behalf that generate provider documentation encourage communication between parents and providers regarding disease management and reduce provider workload.
Gender Differences in South Indians with Premature Coronary Artery Disease (< 40 Years)—Insights from the PCAD Registry
Authors: Shetty Laxmi H. , Patil Rahul S. , Kharge Jayashree , Vijay Kumar J. R. , Ghosh Santu , Manjunath C. N.
Published: October 2021

Introduction Coronary artery disease (CAD) follows a different pattern in women and men, more so in the young (< 40 years). The gender differences in the risk factors, clinical presentation and diagnosis need to be understood, so that appropriate and timely treatment can be given.

Objective The study contemplates to analyze the gender differences in the presence of major coronary risk factors, clinical presentation, diagnosis and immediate outcomes in patients who present with premature CAD (PCAD).

Patients and Methods We evaluated 1,062 consecutive registry patients who presented with diagnosis of PCAD between 2018 to 2019 at our institution after satisfying the inclusion criteria.

Results The study analyses 82 females and 980 males. The mean age of females was 35.4 ± 4.68 years and males was 34.2 ± 4.25 years. Males smoked more often (55.1%,p < 0.001). Females more often had abnormal BMI (84.1%,p < 0.001), increased waist-hip ratios (97.6%,p < 0.001), diabetes (35.4%,p < 0.001), dyslipidemia (17.1% vs. 11%) and hypertension (15.9% vs. 11.5%). STEMI was the most common presentation among males (80.4% vs. 71.9%). Majority of females (74.6%) presented 6 hours after index pain. NSTEMI was more common among females (20.7% vs. 16%). Single-vessel involvement was common in both sexes (84.1% in males and 85.2% in females). Obstructive CAD was less common in both groups.

Conclusions Conventional risk factors play a major role for CAD in Indians. Smoking was common in males and metabolic syndrome in females. Also, females had a higher threshold for seeking treatment and referral. Measures have to be taken for early diagnosis and referral of females. Recanalized and thrombotic coronaries were common, indicating predominant thrombus burden in the young
Correlation between the Clinical Profile and Angiographic Severity of Coronary Artery Disease in ST Elevation Myocardial Infarction and Non-ST Elevation Myocardial Infarction Patients
Authors: Swaminathan C. Rohit , Prasath P. Arun
Published: October 2021

Background and Aim: The correlation between clinical profile and angiographic severity in acute coronary syndrome (ACS) patients has been poorly documented. Hence, the present study aimed to study the clinical profile and correlate that with vessel burden, as witnessed by coronary angiography, in patients presenting to the hospital with ACS (ST-segment elevation myocardial infarction [STEMI]/non-ST-segment elevation [NSTE]-ACS)

Materials and Methods: The study had enrolled 209 patients who had been diagnosed with ACS. All subjects were those who presented to the Emergency Medicine Department in a tertiary care center (south India). Coronary angiogram done for these patients by cardiologists was reviewed with a SYNTAX CALCULATOR (I AND II). Patient's baseline characteristics and clinical examination and interventional diagnosis details were obtained.

Results: The clinical profile gathered from this geographical territory implied an increase in the angiographic severity of the coronary artery disease as measured by the SYNTAX score 1, with an increase in the duration of the said risk factor. Male gender was predominant and the major age group for ACS was 30 to 60 years. The most common presentation in ACS was STEMI. Diabetes and hypertension were the main risk factors for ACS. There was a striking occurrence of ACS among the young.

Conclusion: STEMI was the major ACS presentation in this study population. The main risk factors noted were diabetes and hypertension. Besides smoking and alcohol abuse (in any study population), dyslipidemia was also a key risk factor observed. Mild left ventricular systolic dysfunction was predominant in this study. The SYNTAX score 1 increased with duration of observed and recorded risk factors.
Novel Variants and Clinical Characteristics of 16 Patients from Southeast Asia with Genetic Variants in Neurofibromin-1
Authors: Lin Grace , Wei Heming , Lai Angeline H. M. , Tan Ee-Shien , Lim Jiin Ying , Cham Breana , Ling Simon , Jamuar Saumya S. , Tan Ene-Choo
Published: October 2021

Neurofibromatosis type 1 (NF1) is one of the most common inherited disorders. It is caused by mutations in the neurofibromin-1 gene (NF1) and affects the formation and growth of nerve tissues. More than 3,600 pathogenic variants in the NF1 gene have been identified from patients with most of the germline variants are from the Western populations. We found 16 patients (15 Chinese and 1 Asian Indian) who had heterozygous variants in NF1 through targeted next-generation sequencing. There were 15 different variants: 4 frameshift, 4 nonsense, 5 missense, and 2 splice variants. One nonsense variant and three frameshift variants had never been reported in any population or patient database. Twelve of the 16 patients met the NF1 diagnostic criteria, and each was found to have a pathogenic or likely pathogenic variant. Three different missense variants of unknown significance were discovered in the other four patients who did not meet NF1 diagnostic criteria. Our findings add four novel variants to the list of genetic mutations linked to NF1's various clinical manifestations.
Big data for whose sake? Governing migration through artificial intelligence
Authors: Bircan Tuba , Korkmaz Emre Eren
Published: October 2021

Although human activity constantly generates massive amounts of data, these data can only be analysed by mainly the private sector and governmental institutes due to data accessibility restrictions. However, neither migrants (as the producers of this data) nor migration scholars (as scientific experts on the topic) are in a position to monitor or control how governments and corporations use such data. Big Data analytics and Artificial Intelligence (AI) technologies are promoted as cutting-edge solutions to ongoing and emerging social, economic and governance challenges. Meanwhile, states increasingly rely on digital and frontier technologies to manage borders and control migratory movements, and the defence industry and military–intelligence sectors provide high-tech tools to support these efforts. Worryingly, during the design and testing of algorithmic tools, migrants are often portrayed as a security threat instead of human beings with fundamental rights and liberties. Thus, privacy, data protection, and confidentiality issues continue to pose risks and challenges to migrant communities and raise important questions for the public and decision-makers alike. This comment seeks to shed light on the lack of effective regulation of AI and Big Data as they are applied in migration ‘management’. Additionally, from the perspective of privacy issues and immigrant rights (seeking asylum as a human right, it aims at advocating improved access to Big Data for scientific research which might act as a social control function for the smart border and existing/ongoing migration governance practices of countries. We argue that the use of Big Data and AI for migration governance requires much better collaboration between migrants (including the civil society and grassroots organisations solidarity that represent them), data scientists, migration scholars and policymakers if the potential of these technologies is to be reached in a way that is reasonable and ethical. Numerous critical privacy questions arise are regarding the legal requirements, confidentiality, and rules of engagement as well as the ethical concerns of (mis)use of new technologies. When the secretive nature of the ongoing exploitation of migrant data by states and corporations is considered raising such questions is essential for progress.
Coherent vibrational dynamics of
[Au25(SR)18]- nanoclusters
Authors: Kong Jie , Wu Yan-zhen , Zhou Meng
Published: October 2021

Coherent vibrational dynamics can be observed in atomically precise gold nanoclusters using femtosecond time-resolved pump-probe spectroscopy. It can not only reveal the coupling between electrons and vibrations, but also reflect the mechanical and electronic properties of metal nanoclusters, which holds potential applications in biological sensing and mass detection. Here, we investigated the coherent vibrational dynamics of [Au25(SR)18]− nanoclusters by ultrafast spectroscopy and revealed the origins of these coherent vibrations by analyzing their frequency, phase and probe wavelength distributions. Strong coherent oscillations with frequency of 40 cm−1 and 80 cm−1 can be reproduced in the excited state dynamics of [Au25(SR)18]−, which should originate from acoustic vibrations of the Au13 metal core. Phase analysis on the oscillations indicates that the 80 cm−1 mode should arise from the frequency modulation of the electronic states while the 40 cm−1 mode should originate from the amplitude modulation of the dynamic spectrum. Moreover, it is found that the vibration frequencies of [Au25(SR)18]− obtained in pump-probe measurements are independent of the surface ligands so that they are intrinsic properties of the metal core. These results are of great value to understand the electron-vibration coupling of metal nanoclusters.
Modelling of fume particle behaviour and coupling glass contamination during vacuum laser beam welding
Authors: Lee Yongki , Cheon Jason , Min Byung-Kwon , Kim Cheolhee
Published: October 2021

Vacuum laser beam welding utilises the advantages of both laser and electron beam welding. In this study, a numerical model was developed to simulate fume particle behaviour and the contamination of coupling glass through which the laser beam irradiates the vacuum chamber. Supplying a proper flow rate of shielding gas suppresses the infiltration of fume particles into the protective system and prevents the rising of fumes inside the system. The high momentum of the supplied gas could discharge fume particles out of the protective system and horizontally deflect fume particles away. The developed numerical model showed a good agreement with the experimental results, and a systematic method for designing and optimising the protective system was established.
Transforming laboratory experiments for digital teaching: remote access laboratories in thermodynamics
Authors: Weiszflog Matthias , Goetz Inga K
Published: October 2021

Laboratories in an undergraduate physics course were adapted to remote learning while conserving a high degree of student autonomy regarding the experimental work. The commencement of the COVID-19 pandemic in 2020 and the resulting restrictions for large groups enforced the immediate development and implementation of new teaching concepts. This article describes laboratories, which have been redesigned in order to give the students the possibility to remotely steer and control the experiments by instructing their teachers, who were on site in the laboratory. This interactive approach allowed for a high degree of autonomy and freedom in the experimental design. The assessment of the laboratories, oral presentations by the students, was carried out in a similar format as in previous years, but remotely. The presentations indicated that the students reached a comparable level of understanding of the underlying physics concepts as in years with on-site laboratories. The experiences gathered with this concept can be beneficial beyond the described one-time implementation and allow adaptation for other scenarios of remote courses.
Crossed Andreev reflection in FSF Weyl semimetal junctions
Authors: Azizi Alireza , Abdollahipour Babak
Published: October 2021

We have investigated crossed Andreev reflection in a ferromagnet-superconductor-ferromagnet junction based on the time-reversal invariant Weyl semimetals. We demonstrate that this junction can provide a suitable platform for generating pure crossed Andreev reflection signals. For bipolar junction, n-doped left ferromagnet and p-doped right ferromagnet, pure co-tunneling can happen in the antiparallel configuration of the magnetizations of ferromagnets, while a pure crossed Andreev reflection is possible only in the parallel configuration. However, when both of the ferromagnetic leads have the same polarity, n-doped or p-doped, the situation is reversed. Furthermore, we find that we can tune the chemical potentials and magnetizations of the ferromagnets separately to on or off co-tunneling and crossed Andreev reflection signals. Moreover, we show that the pure crossed Andreev reflection signal can be enhanced by tuning the chemical potentials of two ferromagnetic leads. Our findings may be employed for generating entangled electron pairs in the condensed matter systems.
Models of adsorption-induced deformation: ordered materials and beyond
Authors: Kolesnikov A L , Budkov Yu A , Gor G Y
Published: October 2021

Adsorption-induced deformation is a change in geometrical dimensions of an adsorbent material caused by gas or liquid adsorption on its surface. This phenomenon is universal and sensitive to adsorbent properties, which makes its prediction a challenging task. However, the pure academic interest is complemented by its importance in a number of engineering applications with porous materials characterization among them. Similar to classical adsorption-based characterization methods, the deformation-based ones rely on the quality of the underlying theoretical framework. This fact stimulates the recent development of qualitative and quantitative models toward the more detailed description of a solid material, e.g. account of non-convex and corrugated pores, calculations of adsorption stress in realistic three-dimension solid structures, the extension of the existing models to new geometries, etc. The present review focuses on the theoretical description of adsorption-induced deformation in micro and mesoporous materials. We are aiming to cover recent theoretical works describing the deformation of both ordered and disordered porous bodies.
Structural, electronic, and transport properties of Janus GaInX
2 (X
= S, Se, Te) monolayers: first-principles study
Authors: Vu Tuan V , Linh Tran P T , Phuc Huynh V , Duque C A , Kartamyshev A I , Hieu Nguyen N
Published: October 2021

Two-dimensional Janus monolayers have outstanding electronic and transport properties due to their asymmetric atomic structures. In the present work, we systematically study the structural, electronic, and transport properties of the Janus GaInX
2 (X = S, Se, Te) monolayers by using the first-principles calculations. The stability of the investigated monolayers is confirmed via the analysis of vibrational spectrum and molecular dynamics simulations. Our calculations demonstrate that while GaInS2 and GaInSe2 monolayers are direct semiconductors, GaInTe2 monolayer exhibits the characteristics of an indirect semiconductor. The band gap of GaInX
2 decreases when the chalcogen element X varies from S to Te. Obtained results reveal that small spin–orbit splitting energy in the valence band is found around the Γ point of the Brillouin zone when the spin–orbit coupling is included. Interestingly, GaInS2 and GaInSe2 have high and directional isotropic electron mobility meanwhile the directional anisotropy of the electron mobility is found in the Janus GaInTe2 monolayer. Our findings not only present superior physical properties of GaInX
2 monolayers but also show promising potential applications of these materials in nanoelectronic devices.
Trioctylphosphine accelerated growth of InP quantum dots at low temperature
Authors: Zhang Xinsu , Lv Hao , Xing Weishuo , Li Yanjun , Geng Chong , Xu Shu
Published: October 2021

Significant advance was realized on the economic synthesis of InP quantum dots (QDs) by using aminophosphines as phosphorus precursor. However, the low reaction activity and thermal degradation of aminophosphines bring severe difficulty for growth control of InP QDs. Here, we employed trioctylphosphine (TOP) as a surfactant to accelerate the growth of the InP QDs. The reaction mechanism study reveals that the TOP could form a reactive complex with indium halides that effectively accelerates the formation of InP monomer and reduces the demand for reaction temperature. On this basis, the effect of reaction temperature, precursors, and zinc halide additives on the growth of the TOP-InP QDs was explored. This strategy alleviates the difficulty in growth control of InP QDs and also benefits to the synthesis of luminescent InP/ZnS core–shell QDs within visible regime. A white-light emitting diode device was fabricated with the InP/ZnS QDs that demonstrates their application potential in light-emitting devices.
Classical n-body scattering with long-range potentials
Authors: Fejoz Jacques , Knauf Andreas , Montgomery Richard
Published: October 2021

We consider the scattering of n classical particles interacting via pair potentials which are assumed to be ‘long-range’, i.e. of order

O

(

r

−
α

)

as r tends to infinity, for some α > 0. We define and focus on the ‘free region’, the set of states leading to well-defined and well-separated final states at infinity. As a first step, we prove the existence of an explicit, global surface of section for the free region. This surface of section allows us to prove the smoothness of the map sending a point to its final state and to establish a forward conjugacy between the n-body dynamics and free dynamics.
Topological bifurcation structure of one-parameter families of C
1 unimodal maps
Authors: Sannami Atsuro , Yokoyama Tomoo
Published: October 2021

We consider the bifurcation structure of one-parameter families of unimodal maps whose differentiability is only C
1. The structure of its bifurcation diagram can be a very wild one in such case. However we prove that in a certain topological sense, the structure is the same as that of the standard family of quadratic polynomials. In the case of families of polynomials, irreducible component of the bifurcation diagram can be defined naturally by dividing by the polynomials corresponding to lower periods. We show that such an irreducible component can be defined even if the maps and the family satisfy only a very mild differentiability condition. By removing components of lower periods, the structure of the bifurcation diagram becomes a considerably simplified one. We prove that the symbolic condition for the irreducible components is exactly the same as that of the standard family of quadratic polynomials. When we consider families of maps without strict conditions, the bifurcation diagrams may have infinitely many wild components. We show that such a situation does not affect the irreducible component essentially by proving a separation theorem for compact set in the plane which asserts that a given connected component can be cut out from the compact set by a curve.
Investigating spatial fractionation and radiation induced bystander effects: a mathematical modelling approach
Authors: Cahoon Paul , Giacometti Valentina , Casey Francis , Russell Emily , McGarry Conor , Prise Kevin M , McMahon Stephen J
Published: October 2021

Radiation induced bystander effects (RIBEs) have been shown to cause death in cells receiving little or no physical dose. In standard radiotherapy, where uniform fields are delivered and all cells are directly exposed to radiation, this phenomenon can be neglected. However, the role of RIBEs may become more influential when heterogeneous fields are considered. Mathematical modelling can be used to determine how these heterogeneous fields might influence cell survival, but most established techniques account only for the direct effects of radiation. To gain a full appreciation of how non-uniform fields impact cell survival, it is also necessary to consider the indirect effects of radiation. In this work, we utilise a mathematical model that accounts for both the direct effects of radiation on cells and RIBEs. This model is used to investigate how spatially fractionated radiotherapy plans impact cell survival in vitro. These predictions were compared to survival in normal and cancerous cells following exposure to spatially fractionated plans using a clinical linac. The model is also used to explore how spatially fractionated radiotherapy will impact tumour control in vivo. Results suggest that spatially fractionated plans are associated with higher equivalent uniform doses than conventional uniform plans at clinically relevant doses. The model predicted only small changes changes in normal tissue complication probability, compared to the larger protection seen clinically. This contradicts a central paradigm of radiotherapy where uniform fields are assumed to maximise cell kill and may be important for future radiotherapy optimisation.
Disruption thermal load mitigation with shattered pellet injection on the Joint European Torus (JET)
Authors: Sheikh U.A. , Shiraki D. , Sweeney R. , Carvalho P. , Jachmich S. , Joffrin E. , Lehnen M. , Lovell J. , Nardon E. , Silburn S. , JET Contributors
Published: October 2021

Disruption mitigation remains a critical, unresolved challenge for ITER. To aid in addressing this challenge, a shattered pellet injection (SPI) system was installed on JET and experiments conducted at a range of thermal energy fractions and stored energies in excess of 7 MJ. The primary goals of these experiments were to investigate the efficacy of the SPI on JET and the ability of the plasma to assimilate multiple pellets. Single pellet injections produced a saturation in total radiated energy (W
rad) with increasing injected neon content, suggesting total radiation of stored thermal energy. Further increases in injected neon quantities resulted in reduced cooling times and current quench (CQ) durations, indicating higher impurity assimilation. No significant variation in CQ duration or W
rad was observed when varying the deuterium content at fixed neon quantities. Higher assimilation, inferred by shorter CQ durations, was measured when a mechanical punch was used to launch the pellets and this was attributed to a lower pellet velocity leading to higher solid content in the pellet plume and larger fragments penetrating deeper into the plasma. Radiation asymmetries averaged over the cooling time were inferred from Emis3D and ranged from 1.6 to 1.9. Asymmetries averaged over the entire disruption sequence were found to increase at higher thermal energy fractions. The radiated energy fractions decreased with increasing thermal energy fractions but this trend was eliminated when toroidal asymmetries were accounted for with Emis3D. Pure deuterium pellets were able to produce cooling times of up to 75 ms with a gradual loss in thermal stored energy of up to 80%. Experiments with multiple pellet injection indicated W
rad can be increased through pellet superposition and density can be increased with an additional D2 injection without a reduction in W
rad. KPRAD modelling accurately reproduced the cooling times and the CQ duration at high thermal energies. Assimilation estimates from KPRAD indicated CQ rates scale strongly whilst W
rad scales weakly and saturates with assimilated neon content. Comparable W
rad can be achieved with lower assimilated neon quantities as longer cooling times are attained. Thus reduced neon content can be preferential in a thermal load mitigation scheme as it may reduce radiation asymmetries and prevent flash melting.
Dynamical phase transition in the activity-biased fully-connected random field Ising model: connection with glass-forming systems
Authors: Guioth Jules , Jack Robert L
Published: October 2021

We analyse biased ensembles of trajectories for the random-field Ising model on a fully-connected lattice, which is described exactly by mean-field theory. By coupling the activity of the system to a dynamical biasing field, we find a range of dynamical phase transitions, including spontaneous symmetry breaking into ordered states. For weak bias, the phase behaviour is controlled by extrema of the free energy, which may be local minima or saddle points. For large bias, the system tends to states of extremal activity, which may differ strongly from free energy minima. We discuss connections of these results to random first-order transition theory of glasses, which motivates an extension of the analysis to random-field Ising models where the dynamical activity is not symmetric under magnetisation reversal.
Investigation of interaction of extreme pressure additive, load and sliding speed parameters with silver nano-particles in wear environment
Authors: Ahmaida Yousef Alamin A , Korkmaz Seyma , Kilincarslan Sena Kabave , Sirvan Onur Can , Cetin M Huseyin
Published: October 2021

This study aims to minimize the wear of brass-based sliding bearing materials by using extreme-pressure and nano-silver added lubricants. The nano-fluids used in the experiments were characterized by the Zeta test, size measurement, absorbance graphs, wettability analyses and TEM imaging. The effect of extreme-pressure (5%, 10% and 15%) and nano-silver (1%, 5% and 9%) concentration ratios and the interaction of lubricants with load and speed parameters were analyzed with ball-on-plate wear experiments. The results were analyzed by evaluating the friction coefficient and wear volume values, as well as SEM and 3D topography images. It has been found that 5% extreme pressure lubricant reduces friction coefficient by 32.82% and volume loss by 89.51% compared to base lubricant. According to the results, the lowest friction coefficient (0.0276), volume loss (0.042 mm3) values and the best surface images were obtained at 1% concentration. Furthermore, the tribological performance decreased as the concentration of extreme-pressure and nano-silver increased, and optimum extreme-pressure and nano-silver concentrations were obtained as 5% and 1%, respectively. Using additives, different load (10N, 20N and 30N) and speed (10 rpm, 25 rpm, 40 rpm) parameters, Taguchi’s L9 fractional factorial experimental design was created for interaction analyses. With the Taguchi analysis of the design, 5% extreme pressure added lubricant, 10N load and 40 rpm speed parameter combination was determined as the optimum test condition and base lubricant, 30N load and 25 rpm speed parameters were determined as the worst test condition. According to the variance analyses results, it was determined that the lubricant condition was the most effective parameter on the coefficient of friction (67.79%), volume loss (51.07%) and surface roughness (45.43%).
Energy absorption within elastic range for AZ31 magnesium alloy
Authors: Yang Yongbiao , Zhang TingYan , Guo Jinxuan , Zhang Zhimin , Wang Qiang , Li Guojun
Published: October 2021

Energy absorption for AZ31 magnesium Alloy was investigated with Split Hopkinson Pressure Bar using single stress wave so as to avoid multiple stress wave loading. The stress wave amplitude, which was in elastic stress range and propagated along the AZ31 magnesium bar, was reduced with increasing propagating distance, and with increasing stress wave amplitude, the stress wave amplitude reduction along the magnesium bar was increased losing more energy as compared with that of the stress wave with lower amplitude. The drastically decreased stress wave amplitude could be explained based on dislocations movements, which was similar to the established theory of damping for the explanation of the energy loss during cyclic loading. However, it was not the case for LY12 aluminum alloy: the stress wave amplitude changed slightly without drastic energy loss regardless of the variation of stress wave amplitude.
Adhesion of water-based paint on plasma-treated high-density polyethylene sheets
Authors: De Leon Mark Jeffry D , Vasquez Magdaleno R
Published: October 2021

In this study, high-density polyethylene (HDPE) surfaces were treated with plasma to enhance the adhesion of a water-based paint. A custom-built cold atmospheric pressure plasma jet (CAPPJ) device using a neon transformer as its power source was developed and used in the surface treatment. The jet nozzle of the device was made from polytetrafluoroethylene with two bare stainless-steel electrodes positioned laterally through the nozzle and opposite each other with a 1 mm gap. Gas was allowed to pass through the nozzle, exiting through a 1 mm diameter hole where a plasma jet is ejected through the arc from the electrodes. The effect of plasma treatment on HDPE surfaces was determined. Air and nitrogen were used as the process gases and exposure times were also varied. Hydrophilicity of the surface increased with longer plasma exposure with a corresponding 50% increase in surface free energy compared to the untreated surface. From Fourier transform infrared and x-ray photoelectron spectroscopy analysis, it was seen that plasma treatment introduced oxygen containing functionalities onto the surface. Increase in adhesion of a water-based paint was observed for plasma-treated HDPE sheets.
Modelling and optimizing surface roughness and MRR in electropolishing of AISI 4340 low alloy steel in eco-friendly NaCl based electrolyte using RSM
Authors: Fallah Mohammad Meghdad , Attar Milad Aghaee , Mohammadpour Amir , Moradi Mahmoud , Barka Noureddine
Published: October 2021

Electropolishing (EP) is a reliable post-processing method of the drilled metals for achieving a high-quality surface finish with an appropriate material removal rate. This process has many applications due to its advantages such as improving the surface quality by removing the surface peaks on a micro-scale. The aim of most attempts on this process is setting up the optimum parameters to obtain maximum Material Removal Rate (MRR) with minimum surface roughness. In the present wo k, electropolishing of AISI 4340 low alloy steel immersed in eco-friendly NaCl solution has been studied numerically and experimentally. So, primarily a simulation model was developed for the EP process on cylinder parts in COMSOL Multiphysics which was validated with experimental approaches. The results revealed that the numerical model would be convenient for EP. The experiments were performed using Response Surface Methodology (RSM) to evaluate the effect of input variables on the responses. The effects of input variables electrolyte temperature, current intensity, and primary gap were investigated on the outputs MRR and surface roughness at five levels. Based on the results, the electrolyte temperature and current intensity were more effective parameters on the outputs. Results of ANOVA and regression analysis approach revealed that by increasing the current and electrolyte temperature, the MRR increases correspondingly and surface roughness declines and the primary gap has a reverse effect on the MRR. Finally, by performing a multi-objective optimization using Derringer’s desirability approach, the EP of AISI 4340 with an eco-friendly NaCl solution was optimized.
Growth kinetics of (CuxNi1-x)6Sn5 intermetallic compound at the interface of mixed Sn63Pb37/SAC305 BGA solder joints during thermal aging test
Authors: Cong Sen , Zhang Weiwei , Zhang He , Liu Peng , Tan Xingwen , Wu Lang , An Rong , Tian Yanhong
Published: October 2021

Sn63Pb37/SAC305 mixed solder joint is inevitably in the electronic device requiring high reliability, such as health care, aerospace etc. However, the usage history of mixed solder joint is relatively short and as such their interfacial behaviour and reliability in service has not been completely figure out. Herein, the evolution of microstructures in fully mixed Sn63Pb37/SAC305 BGA solder joints during high-temperature storage were systematically studied. After reflow soldering process, the Pb-rich phases uniformly distributed in the fully mixed joint. During the thermal aging test, the size of Pb-rich phases gradually coarsened. The intermetallic compound (IMC) layers thickness at the two-side interface (upper interface: between the pad on substrate and solder; lower interface: between the pad on PCB and solder) were also increased. Moreover, the growth kinetics models of two-side IMC layer were successfully established according to the Arrhenius equation. IMC layer grows faster at higher temperature, because of higher diffusion coefficient. With the increasing of aging time, the fracture position partially moved from the interface between Ni layer and IMC layer into IMC internal. These results may provide support for the reliable applications of mixed Sn63Pb37/SAC305 solder joints.
Temperature impact on device characteristics of charge plasma based tunnel FET with Si0.5Ge0.5 source
Authors: Mishra Varun , Verma Yogesh Kumar , Agarwal Lucky , Gupta Santosh Kumar
Published: October 2021

In this work, the impact of temperature is investigated on the electrical characteristics of charge plasma-based doping-less double gate tunnel FET (DL-DG-TFET) with a low bandgap source material i.e., Si0.5Ge0.5. The influence of temperature (from 250 K to 450 K) is analysed on several performance parameters of the device such as bandgap, threshold voltage, SS, switching current ratio, ID-VGS, ID-VDS, gate current. The small change in energy bandgap with temperature reflects that device is minimally dependent on temperature. Temperature impact is significant on the sub-threshold region of transfer characteristics due to SRH recombination and trap-assisted tunnelling current. Insignificant variation of gate current with temperature signifies the better reliability of the device. Further, temperature effect is observed on analog parameters such as cut-off frequency, gate capacitance, trans-conductance, output conductance, power delay product (PDP). The minimal variation of analog parameters with temperature assures application of device in high-temperatures.
Machine learning the derivative discontinuity of density-functional theory
Authors: Gedeon Johannes , Schmidt Jonathan , Hodgson Matthew J P , Wetherell Jack , Benavides-Riveros Carlos L , Marques Miguel A L
Published: October 2021

Machine learning is a powerful tool to design accurate, highly non-local, exchange-correlation functionals for density functional theory. So far, most of those machine learned functionals are trained for systems with an integer number of particles. As such, they are unable to reproduce some crucial and fundamental aspects, such as the explicit dependency of the functionals on the particle number or the infamous derivative discontinuity at integer particle numbers. Here we propose a solution to these problems by training a neural network as the universal functional of density-functional theory that (a) depends explicitly on the number of particles with a piece-wise linearity between the integer numbers and (b) reproduces the derivative discontinuity of the exchange-correlation energy. This is achieved by using an ensemble formalism, a training set containing fractional densities, and an explicitly discontinuous formulation.
Codimension growth of Lie algebras with a generalized action
Authors: Janssens Geoffrey
Published: October 2021

Let

F
F

be a field of characteristic

0
0

and

L
L

a finite dimensional Lie

F
F

-algebra endowed with a generalized action by an associative algebra

H
H

. We investigate the exponential growth rate of the sequence of

H
H

-graded codimensions

c
n
H

(
L
)

c_n^H(L)

of

L
L

which is a measure for the number of non-polynomial

H
H

-identities of

L
L

. More precisely, we construct an

S
S

-graded Lie algebra (with

S
S

a semigroup) which has an irrational exponential growth rate (the exact value is obtained). This is the first example of a graded Lie algebra with non-integer exponential growth rate. In addition, we prove an analogue of Amitsur’s conjecture (i.e.

lim

n
→
∞

c
n

H

(
L
)

n

∈

Z

\lim _{n\rightarrow \infty } \sqrt [n]{c_n^{H}(L)} \in \mathbb {Z}

) for general

H
H

under the assumption that

L
L

is both semisimple as Lie algebra and for the

H
H

-action. Moreover if

H
=
F
S

H=FS

is a semigroup algebra the condition that

L
L

is semisimple for the

H
H

-action can be dropped. This is in strong contrast to the associative setting where an infinite family of graded-simple algebras with irrational graded PI-exponent was constructed.
Tukey reductions of nowhere Ramsey to Silver null sets
Authors: Spinas Otmar
Published: October 2021

We prove that the ideal of nowhere Ramsey sets is Tukey reducible to each of the finite-dimensional Silver null ideals. This is in line with an earlier result of the author [Israel J. Math. 211 (2016), pp. 473–480] that the meager ideal is Tukey reducible to the Silver null ideal, and it answers two questions asked by Spinas and Wohofsky [Fund. Math. 254 (2021), pp. 261–303].

We also show that if the homogeneity number

h
m

\mathfrak {hm}

equals

2

ℵ
0

2^{\aleph _0}

, then the additivity of the Marczewski ideal is below the

σ
\sigma

-splitting number

s
σ

\mathfrak {s_\sigma }

.
Noncommutative Riemann hypothesis
Authors: Tabuada Gonçalo
Published: October 2021

In this note, making use of noncommutative

l
l

-adic cohomology, we extend the generalized Riemann hypothesis from the realm of algebraic geometry to the broad setting of geometric noncommutative schemes in the sense of Orlov. As a first application, we prove that the generalized Riemann hypothesis is invariant under derived equivalences and homological projective duality. As a second application, we prove the noncommutative generalized Riemann hypothesis in some new cases.
Stigma shape shifting in sages (Salvia: Lamiaceae): hummingbirds guided the evolution of New World floral features
Authors: Kriebel Ricardo , Drew Bryan T , González-Gallegos Jesús G , Celep Ferhat , Antar Guilherme M , Pastore José Floriano Barêa , Uría Rolando , Sytsma Kenneth J
Published: October 2021

A fundamental question in evolutionary biology is how clades of organisms exert influence on one another. The evolution of the flower and subsequent plant/pollinator coevolution are major innovations that have operated in flowering plants to promote species radiations at a variety of taxonomic levels in the Neotropics. Here we test the hypothesis that pollination by Neotropical endemic hummingbirds drove the evolution of two unique stigma traits in correlation with other floral traits in New World Salvia (Lamiaceae). We examined morphometric shapes of stigma lobing across 400 Salvia spp., scored presence and absence of a stigma brush across Salvia, and used a suite of phylogenetic comparative methods to detect shape regime shifts, correlation of trait shifts with BayesTraits and phylogenetic generalized least square regressions, and the influence of scored pollinators on trait evolution using OUwie. We found that a major Neotropical clade of Salvia evolved a correlated set of stigma features, with a longer upper stigma lobe and stigmatic brush, following an early shift to hummingbird pollination. Evolutionary constraint is evident as subsequent shifts to bee pollination largely retained these two features. Our results support the hypothesis that hummingbirds guided the correlative shifts in corolla, anther connective, style and stigma shape in Neotropical Salvia, despite repeated shifts back to bee pollination.