bluuebunny/crossref_metadata_2025 huggingface dataset:
Decentralised demand response market model based on reinforcement learning
Authors: Shafie‐Khah Miadreza , Talari Saber , Wang Fei , Catalão João P.S.
Published: September 2020

A new decentralised demand response (DR) model relying on bi‐directional communications is developed in this study. In this model, each user is considered as an agent that submits its bids according to the consumption urgency and a set of parameters defined by a reinforcement learning algorithm called Q‐learning. The bids are sent to a local DR market, which is responsible for communicating all bids to the wholesale market and the system operator (SO), reporting to the customers after determining the local DR market clearing price. From local markets’ viewpoint, the goal is to maximise social welfare. Four DR levels are considered to evaluate the effect of different DR portions in the cost of the electricity purchase. The outcomes are compared with the ones achieved from a centralised approach (aggregation‐based model) as well as an uncontrolled method. Numerical studies prove that the proposed decentralised model remarkably drops the electricity cost compare to the uncontrolled method, being nearly as optimal as a centralised approach.
Formal reasoning about synthetic biology using higher‐order‐logic theorem proving
Authors: Abed Sa'ed , Rashid Adnan , Hasan Osman
Published: September 2020

Synthetic biology is an interdisciplinary field that uses well‐established engineering principles for performing the analysis of the biological systems, such as biological circuits, pathways, controllers and enzymes. Conventionally, the analysis of these biological systems is performed using paper‐and‐pencil proofs and computer simulation methods. However, these methods cannot ensure accurate results due to their inherent limitations. Higher‐order‐logic (HOL) theorem proving is proposed and used as a complementary approach for analysing linear biological systems, which is based on developing a mathematical model of the genetic circuits and the bio‐controllers used in synthetic biology based on HOL and analysing it using deductive reasoning in an interactive theorem prover. The involvement of the logic, mathematics and the deductive reasoning in this method ensures the accuracy of the analysis. It is proposed to model the continuous dynamics of the genetic circuits and their associated controllers using differential equations and perform their transfer function‐based analysis using the Laplace transform in a theorem prover. For illustration, the genetic circuits of activated and repressed expressions and autoactivation of protein, and phase lag and lead controllers, which are widely used in cancer‐cell identifiers and multi‐input receptors for precise disease detection, are formally analyzed.
Comparison of Dexmedetomidine Infusion versus Scalp Block with 0.5% Ropivacaine to Attenuate Hemodynamic Response to Skull Pin Insertion in Craniotomy: A Prospective, Randomized Controlled Trial
Authors: Singh Georgene , Arimanikam Ganesamoorthi , Lionel Karen R. , Smita V. , Yadav Bijesh , Arulvelan Appavoo , Sethuraman Manikandan
Published: September 2020

Background The insertion of the skull pin head holder to stabilize the head during neurosurgery causes significant periosteal stimulation, resulting in hemodynamic responses, which may lead to brain edema, intracranial hypertension, and hemorrhage in patients with intracranial space-occupying lesions and intracranial aneurysms. We compared the efficacy of dexmedetomidine infusion and 0.5% ropivacaine scalp block in attenuating the hemodynamic response to the skull pin application.

Methods A total of 65 American Society of Anesthesiologists (ASA) class I and II patients aged between 18 and 65 years with a preoperative Glasgow Coma Scale score of 15 undergoing elective craniotomy were randomized to receive either a bolus of 1mcg/kg of dexmedetomidine followed by an infusion of 1 mcg/kg/hour (group D) or a scalp block with 0.5% ropivacaine (group S) in a single-blinded comparator study. Patients were monitored for the following hemodynamic changes following skull pin insertion: heart rate (HR), mean arterial pressure (MAP), the requirement of additional analgesia/anesthesia, and adverse events.

Results HR and MAP were comparable between the groups at baseline, before induction, and before pin insertion. HR and MAP at 1, 2, and 3 minutes after skull pin insertion were significantly higher in group D as compared with group S (p < 0.05) and were comparable between the groups at 5 minutes. The groups were comparable with respect to the requirement of additional analgesia, anesthesia, and incidence of adverse events.

Conclusion Scalp block with 0.5% ropivacaine is effective and superior to dexmedetomidine in attenuating the hemodynamic response to skull pin insertion in ASA I and II neurosurgical patients undergoing craniotomy. However, the hemodynamic effects achieved with dexmedetomidine were within the permissible limits.
Are the Wear and Osteolysis Outcomes Different between Annealed and Remelted First-Generation Highly Crosslinked Polyethylene after Long-Term Implantation?
Authors: Schachtner Jaclyn T. , MacDonald Daniel W. , Klein Gregg R. , Malkani Arthur L. , Kraay Matthew , Rimnac Clare M. , Mont Michael A. , Lee Gwo-Chin , Kurtz Steven Michael
Published: September 2020

First-generation highly crosslinked polyethylene (HXLPE) was developed to reduce polyethylene wear debris and subsequent osteolysis. Two thermal stabilization strategies were developed, annealing and remelting, to remove free radicals remaining in the polymer. Both types of HXLPEs have demonstrated better wear resistance to conventional polyethylene in hip arthroplasty. However, few studies have directly compared the mid- to long-term clinical outcomes of first-generation HXLPEs. We sought to address the following research questions: (1) is there a difference between the revision reasons for HXLPE formulations (annealed and remelted), (2) is there a difference in oxidation between annealed and remelted HXLPEs, (3) is there a difference in the linear penetration rate of annealed and remelted HXLPEs, and (4) does the formulation of first-generation HXLPEs affect the prevalence of osteolysis? A total of 129 first-generation HXLPE acetabular liners were collected in a multicenter retrieval program. These components were implanted for 5 or more years and were fabricated from annealed or remelted HXLPE. Reasons for revision, body mass index, age, sex, and activity levels were collected from medical records. Oxidation was measured at four regions of interest: bearing surface, backside surface, locking mechanism, and rim. Liner penetration was directly measured from retrievals using a micrometer. Osteolysis was reported in the operative notes by the revising surgeon and a thorough review of the operative notes and radiographs. Revision reasons included infection, instability, pain, and loosening. The annealed liners had higher oxidation indices than remelted liners. There was no difference in linear penetration rates between cohorts. There was no difference in osteolysis prevalence between cohorts. We found remelted HXLPE to be more oxidatively stable than annealed HXLPE but did not find a significant difference in the linear penetration rates or the prevalence of osteolysis. Our findings demonstrate sustained long-term wear resistance of both cohorts of HXLPE. We did not find evidence to support a long-term clinical difference between the formulations of HXLPE.
Noncanonical Effects of Oral Thrombin and Factor Xa Inhibitors in Platelet Activation and Arterial Thrombosis
Authors: Polzin Amin , Dannenberg Lisa , Thienel Manuela , Orban Martin , Wolff Georg , Hohlfeld Thomas , Zeus Tobias , Kelm Malte , Petzold Tobias
Published: September 2020

Nonvitamin K oral anticoagulants (NOACs) or direct oral anticoagulants comprise inhibitors of factor Xa (rivaroxaban, apixaban, edoxaban) or factor IIa (dabigatran). Both classes efficiently interfere with the final or penultimate step of the coagulation cascade and showed superior net clinical benefit compared with vitamin K antagonists for prevention of thromboembolic events in patients with AF and for prevention and therapy of deep vein thrombosis and pulmonary embolism. None the less, accumulating data suggested, that there may be differences regarding the frequency of atherothrombotic cardiovascular events between NOACs. Thus, the optimal individualized NOAC for each patient remains a matter of debate. Against this background, some basic and translational analyses emphasized NOAC effects that impact on platelet activity and arterial thrombus formation beyond inhibition of plasmatic coagulation. In this review, we will provide an overview of the available clinical and translational evidence for so-called noncanonical NOAC effects on platelet activation and arterial thrombosis.
Adverse Events Associated with Implantable Dopplers during Microvascular Surgery
Authors: Pier Matthew M. , Pasick Luke J. , Benito Daniel A. , Saini Prashant , Patel Sahil , Joshi Arjun S. , Goodman Joseph F. , Thakkar Punam
Published: September 2020

Background Implantable Dopplers (IDs) are widely used for postoperative free flap vascular monitoring. However, IDs may contribute to free flap complications or failure and better understanding of device malfunctions is needed.

Methods The U.S. Food and Drug Administration's Manufacturer and User Facility Device Experience database was queried for all reports of ID adverse events from two leading manufacturers (Cook Vascular and Synovis Life Technologies) in free flap surgery from January 2010 to March 2020. Reports were reviewed and categorized. A comparison of reoperations within select categories was performed using Chi-square analysis.

Results Of 209 included reports, the most common device malfunctions were venous anastomotic coupler misalignment (35.4%) and coupler ring detachment (24.4%). Synovis devices were used in 100% of reports of vessel compression and Cook Vascular devices were used in 77.7% of reports of probe detachment. Of 74 patient-related adverse events, the most common were reoperation (47.3%) and vessel occlusion (28.4%). Of five reported events of flap failure, two were associated with loss of ID signal. The proportion of Doppler signal loss events leading to reoperation was significantly greater than the proportion of any other Doppler-related event leading to reoperation. Intraoperative coupler replacement was the most commonly reported intervention (n = 86), and venous anastomosis with hand-suturing occurred in 30 device malfunctions.

Conclusion This study demonstrates a variety of ID-related malfunctions. One-third of device malfunctions were associated with patient complications, and false-positive Doppler signal loss contributed substantially to the requirement of surgical re-exploration. These are important considerations for surgical teams utilizing IDs in free tissue transfer procedures.
Effects of Sucrose and Nonnutritive Sucking on Pain Behavior in Neonates and Infants undergoing Wound Dressing after Surgery: A Randomized Controlled Trial
Authors: Mandee Sahatsa , Buachai Kusuma , Aroonpruksakul Naiyana , Tantemsapya Niramol , Buasuk Tarinee
Published: September 2020

Introduction Wound dressing, a procedure that pediatric patients are commonly exposed to postoperatively, can cause strong physiological and pain behavioral responses despite being brief. This study evaluated the effects of using 24% sucrose plus a pacifier versus a pacifier alone to reduce the pain response from dressing wounds in neonates and infants.

Materials and Methods Thirty-two neonates and infants who underwent surgery and required postoperative wound dressing were randomized to a pacifier group (n = 16) and a 24% sucrose plus pacifier group (“sucrose group”; n = 16). Demographic data, crying time, and pain behaviors were recorded using a video recorder. The pain behaviors were assessed independently using the neonatal infant pain scale (NIPS) by three assessors, who were expert in pediatric pain assessment and blinded to the subject allocations.

Results Participants in the sucrose group were older than those in the pacifier group (6.19 ± 2.95 vs. 3.88 ± 3.2 months). While there were no differences in the NIPS scores of the two groups at 30, 120, and 240 seconds, the incidence of moderate-to-severe pain was lower in the sucrose group than the pacifier group at 120 seconds (37.5 vs. 50%). The crying time was lower in the sucrose group, but without statistical significance.

Conclusion The 24% sucrose plus pacifier was not superior to the pacifier alone in decreasing pain behavioral responses. Dressing wound pain produced a high-intensity pain behavioral response. A pain management strategy should be developed to lessen the postoperative procedural pain in pediatric patients.
Nasal Analysis of Classic Animated Movie Villains versus Hero Counterparts
Authors: Allen Meredith A. , Lucas Jordyn P. , Chung Michael , Rayess Hani M. , Zuliani Giancarlo
Published: September 2020

Opposing facial features between animated villains and heroes have historically been used to demonstrate contrasting morality between characters, and this could have an impact on how humans view someone as good or evil in everyday life. Studies have been done investigating classic dermatologic features of villainous characters. This principle can be applied to nasal features as well. A search for “top animated characters” was performed. Characters were chosen from American Film Institute's “The Top Tens,” Rolling Stone's “25 Best Pixar Movie Characters,” and Screenrant's “The 30 Best Animated Movie Characters of All Time.” Twenty villains and twenty hero counterparts from respective films were chosen. Classic nasal features were analyzed. Twenty villains (14 male, 6 female) and 20 heroes (12 male, 8 female) were analyzed. Sixteen villains (80%) had greater than normal nasal frontal angle versus 18 heroes (90%). Thirteen villains (65%) had an acute nasolabial angle versus two heroes (10%). Two villains (10%) had excess columellar show versus seven heroes (35%). Seven villains (35%) and one hero (5%) had a dorsal hump. Twelve villains (60%) had an overprojected chin versus three heroes (15%). Villains in pre-2000s films more frequently had a dorsal hump, overprojected chin, ptotic tip, pollybeak deformity, and bulbous tip. Heroes in pre-2000s films more frequently had an overrotated tip. Villains and heroes commonly have a greater than normal nasofrontal angle. Villains more commonly have an acute nasolabial angle, underrotated tip, overprojected chin, dorsal hump, and pollybeak deformity. Heroes more commonly have a large nasolabial angle and overrotated tip. Further research in conjunction with psychologists is required to obtain concrete data on how this affects whether an individual in real life is seen as good or evil, and the impact this has on interactions in society, including in the medical field.
Comparative Study of Sealing Ability of Different Filling Materials for Root End: An In Vitro Evaluation
Authors: Bhatia Shagun , Jain Ankush , Sood Himanshu , Jain Kanu
Published: September 2020

Introduction Failure in surgical endodontic techniques can occur most commonly due to improper seal in the apical region. The root-end filling material used should not allow the contamination of the periapical tissue. The aim of the present study was to compare the ability of white mineral trioxide aggregate (MTA), white Portland cement (PC) and intermediate restorative material (IRM) for sealing root-end by dye leakage test.

Materials and Methods 120 teeth with single root were prepared through instruments. Following obturation, the apex was cut, and a cavity was made. Then, the teeth were divided into four groups (Group I: MTA, Group II: white PC, Group III: IRM, Group IV: control). Cavities made at apex in the first three groups were then filled with the respective materials. Exposure to the dye, India Ink, was then done for a time period of 72 hours. The depth of penetration of dye inside the whole root was then evaluated with a magnification of 16X under stereomicroscope in vitro.

Result MTA showed statistically significant difference in sealing ability (p < 0.05) as compared with other materials.

Conclusion MTA cement showed better sealing ability. It is an ideal retrograde filling material, because it is a biocompatible material and has a good marginal adaptation as compared with PC which, in turn, showed better sealing ability than IRM.
Simultaneous Eulerian–Lagrangian velocity measurements of particulate pipe flow in transitional regime
Authors: Singh S. , Pothérat A. , Pringle C. C. T. , Bates I. R. J. , Holdsworth Martin
Published: September 2020

We present a unique pipe flow rig capable of simultaneous particle tracking and flow velocity measurements in a dilute, neutrally buoyant particulate pipe flow in regimes of transition to turbulence. The flow consists of solid glass spheres for the disperse phase and a density-matching fluid for the carrier phase. The measurements are conducted using a bespoke, combined two-dimensional particle image velocimetry and particle tracking velocimetry technique. The technique takes advantage of a phase discrimination approach that involves separating the disperse and carrier phases based on their respective image characteristics. Our results show that the rig and the technique it implements can effectively be employed to study transitional particulate pipe flows at dilute concentrations.
Fabrication of high-breakdown GaN Schottky barrier diodes over deeply-etched crystal surfaces
Authors: Mo Chen , Wang Li , Galgano Xavier , Zhang Yu , Xu Jian
Published: September 2020

We report in this paper an effective method to recover the defects on GaN surfaces following inductively coupled-plasma (ICP) deep-etching using KOH treatment with optimized concentration. GaN Schottky barrier diodes are fabricated over the unintentionally doped GaN buffer region of LED epi-wafers with this method, which achieves a high breakdown over 200 V as revealed in our measurement. This was accompanied with a dramatically reduced leakage current by four orders of magnitude. Temperature-variable current–voltage characterization of the fabricated Schottky junctions and the subsequent carrier transport analysis indicate that the surface concentration of the n-type dopants reduces by more than 20-folds, confirming the effectiveness of the KOH treatment in removing the ICP-induced surface defects.
Detection and control of single proton spins in a thin layer of diamond grown by chemical vapor deposition
Authors: Sasaki Kento , Watanabe Hideyuki , Sumiya Hitoshi , Itoh Kohei M. , Abe Eisuke
Published: September 2020

We report detection and coherent control of a single proton nuclear spin using an electronic spin of the nitrogen-vacancy (NV) center in diamond as a quantum sensor. In addition to determining the NV–proton hyperfine parameters by employing multipulse sequences, we polarize and coherently rotate the single proton spin and detect an induced free precession. Observation of free induction decays is an essential ingredient for high resolution proton nuclear magnetic resonance, and the present work extends it to the atomic scale. We also discuss the origin of the proton as incorporation during chemical vapor deposition growth, which provides an opportunity to use protons in diamond as built-in quantum memories coupled with the NV center.
Relativistic correction scheme for core-level binding energies from GW
Authors: Keller Levi , Blum Volker , Rinke Patrick , Golze Dorothea
Published: September 2020

We present a relativistic correction scheme to improve the accuracy of 1s core-level binding energies calculated from Green’s function theory in the GW approximation, which does not add computational overhead. An element-specific corrective term is derived as the difference between the 1s eigenvalues obtained from the self-consistent solutions to the non- or scalar-relativistic Kohn–Sham equations and the four-component Dirac–Kohn–Sham equations for a free neutral atom. We examine the dependence of this corrective term on the molecular environment and the amount of exact exchange in hybrid exchange–correlation functionals. This corrective term is then added as a perturbation to the quasiparticle energies from partially self-consistent and single-shot GW calculations. We show that this element-specific relativistic correction, when applied to a previously reported benchmark set of 65 core-state excitations [D. Golze et al., J. Phys. Chem. Lett. 11, 1840–1847 (2020)], reduces the mean absolute error (MAE) with respect to the experiment from 0.55 eV to 0.30 eV and eliminates the species dependence of the MAE, which otherwise increases with the atomic number. The relativistic corrections also reduce the species dependence for the optimal amount of exact exchange in the hybrid functional used as a starting point for the single-shot G0W0 calculations. Our correction scheme can be transferred to other methods, which we demonstrate for the delta self-consistent field (ΔSCF) approach based on density functional theory.
An accurate semiempirical potential energy curve for the a3Σ+-state of KRb
Authors: Schwarzer Michael , Toennies J. Peter
Published: September 2020

A semiempirical potential energy curve for the a3Σ+-state of the KRb molecule with only five parameters is reported. The potential is continuous over the entire range of internuclear distances and has the correct long-range attractive dispersion potential from established theory. The potential provides an equally good fit of the laser induced fluorescence Fourier transform spectroscopic data of Pashov et al. [Phys. Rev. A 76, 022511 (2007)] as their multi-parameter potential. The new potential is supported by the good agreement of the well parameters De, Re and the harmonic vibrational constant ωe with combining-rule estimates. The scattering lengths for all six isotopologues are also in excellent agreement with experiment with a 0.2% adjustment within theoretical uncertainty of the leading dispersion coefficient C6. An analysis of the harmonic vibrational constant ωe and the constant ωexe of the potential of Pashov et al. reveals a significant difference to the present potential which turned out to be due to an oscillatory deviation in their potential in the vicinity of the potential minimum. The new potential is, thus, the best available because its simplicity is ideal for further applications.
Spin–orbit torque-induced multiple magnetization switching behaviors in synthetic antiferromagnets
Authors: Zhu Libai , Xu Xiaoguang , Wang Mengxi , Meng Kangkang , Wu Yong , Chen Jikun , Miao Jun , Jiang Yong
Published: September 2020

This paper studies spin–orbit torque (SOT) switching behaviors in synthetic antiferromagnet (SyAF) structures of Ta/[Pt/Co]m/Ru/[Co/Pt]n, which are asymmetric between the upper multilayer (UML) and the bottom multilayer (BML). The SOT-induced magnetization switching loops show multiple transitions of switching orientations between clockwise and anticlockwise with an increasing in-plane magnetic field, determined by the effects of the Dzyaloshinskii–Moriya interaction from both the BML and UML in the different stacking structures. Moreover, the field-free SOT switching was observed in the structure of Ta/[Pt/Co]3/Ru (0.5)/[Co/Pt]4. It can be attributed to the horizontal component of magnetic moments in its UML acting as an equivalent field. Therefore, the SyAF structures could be potential candidates for the future SOT-based spintronic devices.
Phononic bandgap and phonon anomalies in HfN and HfN/ScN metal/semiconductor superlattices measured with inelastic x-ray scattering
Authors: Chakraborty Sourjyadeep , Uchiyama Hiroshi , Garbrecht Magnus , Bhatia Vijay , Pillai Ashalatha Indiradevi Kamalasanan , Feser Joseph Patrick , Adroja Devashibhai T. , Langridge Sean , Saha Bivas
Published: September 2020

Epitaxial metal/semiconductor superlattice heterostructures with lattice-matched abrupt interfaces and suitable Schottky barrier heights are attractive for thermionic energy conversion, hot electron-based solar energy conversion, and optical hyperbolic metamaterials. HfN/ScN is one of the earliest demonstrations of epitaxial single-crystalline metal/semiconductor heterostructures and has attracted significant interest in recent years to harness its excellent properties in device applications. Although the understanding of the mechanism of thermal transport in HfN/ScN superlattices is extremely important for their practical applications, not much attention has been devoted to measuring their phonon dispersion and related properties. In this Letter, we employ non-resonant meV-resolution inelastic x-ray scattering to determine the momentum-dependent phonon modes in epitaxial metallic HfN and lattice-matched HfN/ScN metal/semiconductor superlattices. HfN exhibits a large phononic bandgap (∼40 meV) and Kohn anomaly in the longitudinal and transverse acoustic phonon modes at q ∼ 0.73 along the [100] and [110] directions of the Brillouin zone due to the nesting of the Fermi surface by the wave vector (q). The in-plane [100] acoustic phonon dispersion of the HfN/ScN superlattices is found to be dominated by the HfN phonons, while the optical phonons exhibit both ScN and HfN characteristics. First-principles density functional perturbation theory modeling is performed to explain the experimental phonon spectra, and temperature-dependent thermal conductivity is measured using a pump-probe spectroscopic technique. These results will help understand the phonons in HfN and HfN/ScN metal/semiconductor superlattices for thermionic energy conversion.
Theoretical modeling of triboelectric nanogenerators (TENGs)
Authors: Shao Jiajia , Willatzen Morten , Wang Zhong Lin
Published: September 2020

Triboelectric nanogenerators (TENGs), using Maxwell's displacement current as the driving force, can effectively convert mechanical energy into electricity. In this work, an extensive review of theoretical models of TENGs is presented. Based on Maxwell's equations, a formal physical model is established referred to as the quasi-electrostatic model of a TENG. Since a TENG is electrically neutral at any time owing to the low operation frequency, it is conveniently regarded as a lumped circuit element. Then, using the lumped parameter equivalent circuit theory, the conventional capacitive model and Norton's equivalent circuit model are derived. Optimal conditions for power, voltage, and total energy conversion efficiency can be calculated. The presented TENG models provide an effective theoretical foundation for understanding and predicting the performance of TENGs for practical applications.
Nuclear magnetization distribution effect in molecules: Ra+ and RaF hyperfine structure
Authors: Skripnikov Leonid V.
Published: September 2020

Recently, the first laser spectroscopy measurement of the radioactive RaF molecule has been reported by Ruiz et al. [Nature 581, 396 (2020)]. This and similar molecules are considered to search for the new physics effects. The radium nucleus is of interest as it is octupole-deformed and has close levels of opposite parity. The preparation of such experiments can be simplified if there are reliable theoretical predictions. It is shown that the accurate prediction of the hyperfine structure of the RaF molecule requires to take into account the finite magnetization distribution inside the radium nucleus. For atoms, this effect is known as the Bohr–Weisskopf (BW) effect. Its magnitude depends on the model of the nuclear magnetization distribution which is usually not well known. We show that it is possible to express the nuclear magnetization distribution contribution to the hyperfine structure constant in terms of one magnetization distribution dependent parameter: BW matrix element for 1s-state of the corresponding hydrogen-like ion. This parameter can be extracted from the accurate experimental and theoretical electronic structure data for an ion, atom, or molecule without the explicit treatment of any nuclear magnetization distribution model. This approach can be applied to predict the hyperfine structure of atoms and molecules and allows one to separate the nuclear and electronic correlation problems. It is employed to calculate the finite nuclear magnetization distribution contribution to the hyperfine structure of the 225Ra+ cation and 225RaF molecule. For the ground state of the 225RaF molecule, this contribution achieves 4%.
A Weyl entropy of pure spacetime regions
Authors: Belgiorno Francesco , Catino Giovanni
Published: September 2020

We focus on the Penrose’s Weyl curvature hypothesis in a general framework encompassing many specific models discussed in literature. We introduce a candidate density for the Weyl entropy in pure spacetime perfect fluid regions and show that it is monotonically increasing in time under very general assumptions. Then we consider the behavior of the Weyl entropy of compact regions, which is shown to be monotone in time as well under suitable hypotheses, and also maximal in correspondence with vacuum static metrics. The minimal entropy case is discussed too.
Ultrasensitive detection of antigen–antibody interaction and triglycerides in liquid ambient using polysilicon cantilevers
Authors: Chinnamani M V , Bhadra Priyanka , Fidal V T , Gayathri S , Chadha Anju , Bhattacharya Enakshi
Published: September 2020

Measurement in liquid media is a major challenge in real-time detection using resonant cantilevers. This is addressed in the present study by fabricating sub-micron thick cantilevers followed by functionalization for biomolecule detection.

The fabricated cantilever resonator beams of thickness 165 nm were used for measurements in two systems: (i) human immunoglobulin (HIgG) as the antibody on the cantilever sensing mouse immunoglobulin (MIgG) as corresponding antigen, and (ii) detection of triglyceride (TG) based on the enzymatic hydrolysis with lipase, using tributyrin as a model. In both cases, the beams were functionalized for covalent bonding of the protein receptor. The label-free detection was carried out by measuring the shift in resonance frequency at higher modes, using a laser Doppler vibrometer in liquid and in air.

The calibration showed a linear correlation between the bioanalyte concentration and change in the resonance frequency. Notably, detection of antigen mass as low as 434 ± 59fg and triglyceride concentration in the nM range with limit of detection as 7 nM in liquid interface was achieved, greatly improving the sensitivity of bioanalyte detection in liquid samples.

Although frequency-based methods are highly sensitive, the issues with measurement liquid medium limit their application. In the present report, these issues were addressed by fabricating sub-micron thick cantilever beam, choosing an appropriate functionalization method without affecting the sensitivity, and measurement at higher modes. These have resulted in circumventing issues like damping and hydrodynamic loading thus improving its potential as real-time sensor.
Optimisation of vortex tubes and the potential for use in atmospheric separation
Authors: Agarwal Gautam , McConkey Zack P , Hassard Dr. John
Published: September 2020

Climate change requires us to extract hundreds of gigatonnes of CO2 from the atmosphere over the next few decades. This requires we develop and scale up viable technologies to sequester CO2 from the highly dilute atmospheric concentrations. CO2 gas freezes at −78.5 °C and thus, in principle, can be separated from air, the nitrogen in which begins to freeze at −210 °C. Vortex tubes were investigated as a potential method of carbon capture through a series of geometrical and procedural optimisations. Ambient air is compressed and then separated by temperature due to the action of the Vortex Tube. These optimisations determined an increase in system pressure and length at cold mass fraction of 40% led to increased cooling. The heat profile of pipes suggested radiative cooling as the vortex propagated. An optimised single tube reached a maximum cooling of 39.9±2 °C. Vortex tubes thus present a method of separating and capturing components of the atmosphere. With further work, such as the successful combination of tubes in series, it is hoped that vortex tubes may prove to be a scalable solution capable of contributing to the reduction in atmospheric CO2 using the solar cyclone tower to provide the energy and air flows required for this task.
An ordered-disordered separated graphene nanoribbon: high thermoelectric performance
Authors: Ganguly Sudin , Maiti Santanu K
Published: September 2020

The key requirement for an enhanced thermoelectric (TE) performance is the presence of asymmetry in transmission function. Focussing on this issue, we propose a unique idea to enhance TE performance in a graphene nanoribbon (GNR) that has not been explored so far to the best of our concern. In the present work, one part of the GNR is considered as a disordered region while the rest of the system is clean. Such an ordered-disordered separated structure yields more asymmetric transmission function over the conventional uniform disordered one. Finally, we include the effect of electron–electron (e–e) interaction to check whether it brings any non-trivial signature on TE performance. The e–e interaction is taken in the form of an on-site Hubbard model and we compute our results within a Hartree–Fock mean field approach. The results obtained in the present work exhibit quite remarkable TE performance along with some non-trivial features.
Interaction between impurity elements (C, N and O) and hydrogen in hcp-Zr: a first-principles study
Authors: Feng Menglin , Liu Guangdong , Liu Zhixiao , Hu Wangyu , He Xinfu , Deng Huiqiu
Published: September 2020

Zirconium (Zr) alloys as cladding materials are widely used in fission reactors. The service life of Zr-based materials cladding is seriously affected by the hydrogen (H) behaviors; while the impurities (C, N and O) in Zr alloys have a great influence on the hydrogen behaviors. In this work, we have investigated the impurity–hydrogen interactions in hexagonal-closed packed Zr (hcp-Zr) by a first-principles approach. It was found that H atom tends to occupy tetrahedral interstitial position in perfect Zr and occupy octahedral interstitial position in Zr with vacancy, while the impurities tend to occupy octahedral interstitial positions in Zr both with and without vacancy. The impurities can trap H atoms. Four possible paths were studied for the diffusion of H atom in hcp-Zr, and it is found that the diffusion barriers of H varied with the presence of impurities.
Non-linear nanoscale piezoresponse of single ZnO nanowires affected by piezotronic effect
Authors: Lozano Helena , Catalán Gustau , Esteve Jaume , Domingo Neus , Murillo Gonzalo
Published: September 2020

Zinc oxide (ZnO) nanowires (NWs) as semiconductor piezoelectric nanostructures have emerged as material of interest for applications in energy harvesting, photonics, sensing, biomedical science, actuators or spintronics. The expression for the piezoelectric properties in semiconductor materials is concealed by the screening effect of the available carriers and the piezotronic effect, leading to complex nanoscale piezoresponse signals. Here, we have developed a metal–semiconductor–metal model to simulate the piezoresponse of single ZnO NWs, demonstrating that the apparent non-linearity in the piezoelectric coefficient arises from the asymmetry created by the forward and reversed biased Schottky barriers at the semiconductor–metal junctions. By directly measuring the experimental I–V characteristics of ZnO NWs with conductive atomic force microscope together with the piezoelectric vertical coefficient by piezoresponse force microscopy, and comparing them with the numerical calculations for our model, effective piezoelectric coefficients in the range d
33eff ∼ 8.6 pm V−1–12.3 pm V−1 have been extracted for ZnO NWs. We have further demonstrated via simulations the dependence between the effective piezoelectric coefficient d
33eff and the geometry and physical dimensions of the NW (radius to length ratio), revealing that the higher d
33eff is obtained for thin and long NWs due to the tensor nature proportionality between electric fields and deformation in NW geometries. Moreover, the non-linearity of the piezoresponse also leads to multiharmonic electromechanical response observed at the second and higher harmonics that indeed is not restricted to piezoelectric semiconductor materials but can be generalized to any type of asymmetric voltage drops on a piezoelectric structure as well as leaky wide band-gap semiconductor ferroelectrics.
Piezoelectric polymer energy harvesting system fluctuating in a high speed wind-flow around a running electric vehicle
Authors: Kim Cheol , Park Chang-min , Yoon Jin-young , Park Sang-young
Published: September 2020

The battery of electric vehicles (EVs) is the only power source for the operation of an electric motor, heating and cooling devices, and many other auxiliaries. Therefore, the EV may be vulnerable to electricity shortage during running. It may be good if turbulent flow or vortex induced vibrations occurring around a vehicle body can be transformed into electricity by a piezoelectric energy harvester. In this study, an electric energy harvester has been developed in the forms of thin piezoelectric polymer beams and plates in order to supply auxiliary electric power for EV. The piezoelectric thin beam and plate can be installed as a grill structure or on the surface of a car while two edges of the harvesting structures are fixed and they fluctuate due to the various high-speed airflow-induced vibrations during running of the vehicle. The vortex shedding pressures around the piezoelectric systems and a whole car are computed on the basis of computational fluid dynamic transient analyses with FLUENT. The displacements and resulting voltages of energy harvesting structures are computed by using ANSYS piezoelectric finite element analyses which use the input loadings of the transient vortex shedding pressures obtained from CFD. As results of analyses, a reasonable amount of electric power applicable for the charge of an EV battery can be harvested from the passing wind around a vehicle. The 0.12 mm-thin PVDF beam-type (260 mm × 10 mm) and the plate-type (75 mm × 30 mm) generated the maximum 61.43 volt and 21.5 mW power and 4.77 volt and 0.191 mW at the air-speed of 90 km h−1 in the wind tunnel tests, respectively. The two types of harvesting systems installed on a car were also tested while driving the real car. The test results showed the good agreements with numerical predictions and wind tunnel test results.
A novel stick-slip piezoelectric rotary actuator designed by employing a centrosymmetric flexure hinge mechanism
Authors: Wang Yirui , Xu Zhi , Huang Hu
Published: September 2020

Although the stick-slip piezoelectric linear actuators have been widely investigated, the design of stick-slip piezoelectric rotary actuators is rarely reported and the corresponding output performances could be further improved. In this study, by employing a centrosymmetric flexure hinge mechanism, a novel stick-slip piezoelectric rotary actuator was designed. Its structure and working processes were addressed in detail, and the main structural parameters of the centrosymmetric flexure hinge mechanism were designed by the finite-element method. After that, a prototype was fabricated and a series of experiments were performed to test its output performances. The experimental results showed that under various driving voltages, the actuator could output stable angular displacement, and with increase in the driving voltage, the angular speed tended to linearly increase. Under the driving voltage of 100 V and driving frequency of 600 Hz, the actuator reached a maximum angular speed of about 55 000 μrad s−1. The driving resolution of the actuator was 0.34 μrad, and the maximum vertical loading capacity and torque were tested to be 6 kg and 30 N · mm, respectively. In addition, both clockwise and anticlockwise rotations were realized by simply changing the direction of the driving voltage waveform, and furthermore, under the same experimental conditions, very similar output performances were achieved in clockwise and anticlockwise rotations. Compared with some previously reported stick-slip piezoelectric rotary actuators, it was confirmed that the vertical loading capacity and driving resolution of the designed actuator here had been improved, which would be beneficial to its practical application.
Decreased resilience in power grids under dynamically induced vulnerabilities
Authors: Galindo-González C C , Angulo-Garcia D , Osorio G
Published: September 2020

In this paper, a methodology inspired on bond and site percolation methods is applied to the estimation of the resilience against failures in power grids. Our approach includes vulnerability measures with both dynamical and structural foundations as an attempt to find more insights about the relationships between topology and dynamics in the second-order Kuramoto model on complex networks. As test cases for numerical simulations, we use the real-world topology of the Colombian power transmission system, as well as randomly generated networks with spatial embedding. It is observed that, by focusing the attacks on those dynamical vulnerabilities, the power grid becomes, in general, more prone to reach a state of total blackout, which in the case of node removal procedures it is conditioned by the homogeneity of power distribution in the network.
Complementary properties of multiphoton quantum states in linear optics networks
Authors: Wu Jun-Yi , Murao Mio
Published: September 2020

We have developed a theory for accessing quantum coherences in mutually unbiased bases associated with generalized Pauli operators in multiphoton multimode linear optics networks (LONs). We show a way to construct complementary Pauli measurements in multiphoton LONs and establish a theory for evaluation of their photonic measurement statistics without dealing with the computational complexity of Boson samplings. This theory extends characterization of complementary properties in single-photon LONs to multiphoton LONs employing convex-roof extension. It allows us to detect quantum properties such as entanglement using complementary Pauli measurements, which reveals the physical significance of entanglement between modes in bipartite multiphoton LONs.
Goldstone Apple Valley Radio Telescope Monitoring Flux Density of Jupiter's Synchrotron Radiation during the Juno Mission
Authors: Velusamy T. , Adumitroaie V. , Arballo J. , Levin S. M. , Ries P. A. , Dorcey R. , Kreuser-Jenkins N. , Leflang J. , Jauncey D. , Horiuchi S.
Published: September 2020

Goldstone Apple Valley Radio Telescope (GAVRT) is a science education partnership among NASA, the Jet Propulsion Laboratory (JPL), and the Lewis Center for Educational Research (LCER), offering unique opportunities for K-12 students and their teachers. As part of a long-term Jupiter synchrotron radiation (JSR) flux density monitoring program, LCER has been carrying out Jupiter observations with some student participation. In this paper we present the results of processed data sets observed between 2015 March 6 and 2018 April 6. The data are divided into 5 epochs, grouped by time and by Jupiter’s ephemeris parameters as observed from Earth. We derive JSR beaming curves at different epochs and Earth declinations. We present a comparison of the observed beaming curves with those derived from most recent models for the radiation belts. Our results show an increasing trend of the JSR flux density which seem consistent with the models for the magnetospheric solar wind interactions.
Exocomets from a Solar System Perspective
Authors: Strøm Paul A. , Bodewits Dennis , Knight Matthew M. , Kiefer Flavien , Jones Geraint H. , Kral Quentin , Matrà Luca , Bodman Eva , Capria Maria Teresa , Cleeves Ilsedore , Fitzsimmons Alan , Haghighipour Nader , Harrison John H. D. , Iglesias Daniela , Kama Mihkel , Linnartz Harold , Majumdar Liton , de Mooij Ernst J. W. , Milam Stefanie N. , Opitom Cyrielle , Rebollido Isabel , Rogers Laura K. , Snodgrass Colin , Sousa-Silva Clara , Xu Siyi , Lin Zhong-Yi , Zieba Sebastian
Published: September 2020

Exocomets are small bodies releasing gas and dust which orbit stars other than the Sun. Their existence was first inferred from the detection of variable absorption features in stellar spectra in the late 1980s using spectroscopy. More recently, they have been detected through photometric transits from space, and through far-IR/mm gas emission within debris disks. As (exo)comets are considered to contain the most pristine material accessible in stellar systems, they hold the potential to give us information about early stage formation and evolution conditions of extra solar systems. In the solar system, comets carry the physical and chemical memory of the protoplanetary disk environment where they formed, providing relevant information on processes in the primordial solar nebula. The aim of this paper is to compare essential compositional properties between solar system comets and exocomets to allow for the development of new observational methods and techniques. The paper aims to highlight commonalities and to discuss differences which may aid the communication between the involved research communities and perhaps also avoid misconceptions. The compositional properties of solar system comets and exocomets are summarized before providing an observational comparison between them. Exocomets likely vary in their composition depending on their formation environment like solar system comets do, and since exocomets are not resolved spatially, they pose a challenge when comparing them to high fidelity observations of solar system comets. Observations of gas around main sequence stars, spectroscopic observations of “polluted” white dwarf atmospheres and spectroscopic observations of transiting exocomets suggest that exocomets may show compositional similarities with solar system comets. The recent interstellar visitor 2I/Borisov showed gas, dust and nuclear properties similar to that of solar system comets. This raises the tantalising prospect that observations of interstellar comets may help bridge the fields of exocomet and solar system comets.
Effect of structural complexities in head modeling on the accuracy of EEG source localization in neonates
Authors: Azizollahi Hamed , Aarabi Ardalan , Wallois Fabrice
Published: September 2020

Objective. Neonatal electroencephalography (EEG) source localization is highly prone to errors due to head modeling deficiencies. In this study, we investigated the effect of head model complexities on the accuracy of EEG source localization in full term neonates using a realistic volume conductor head model. Approach. We performed numerical simulations to investigate source localization errors caused by cerebrospinal fluid (CSF) and fontanel exclusion and gray matter (GM)/white matter (WM) distinction using the finite element method. Main results. Our results showed that the exclusion of CSF from the head model could cause significant localization errors mostly for sources closer to the inner surface of the skull. With a less pronounced effect compared to the CSF exclusion, the discrimination between GM and WM also widely affected all sources, especially those located in deeper structures. The exclusion of the fontanels from the head model led to source localization errors for sources located in areas beneath the fontanels. Our finding clearly shows that the CSF inclusion and GM/WM distinction in EEG inverse modeling can substantially reduce EEG source localization errors. Moreover, fontanels should be included in neonatal head models, particularly in source localization applications, in which sources of interest are located beneath or in vicinity of fontanels. Significance. Our ﬁndings have practical implications for a better understanding of the impact of head model complexities on the accuracy of EEG source localization in neonates.