bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multi-phase equation of state of ultrapure hafnium to 120 GPa
Authors: Huston L Q , Velisavljevic N , Smith J S , Gray G T , Sturtevant B T 
Published: October 2021

Abstract
Hafnium (Hf) is an industrially important material due to its large neutron absorption cross-section and its high corrosion resistance. When subjected to high pressure, Hf phase transforms from its hexagonal close packed α-Hf phase to the hexagonal ω-Hf phase. Upon further compression, ω-Hf phase transforms to the body centered cubic β-Hf phase. In this study, the high pressure phase transformations of Hf are studied by compressing and decompressing a well-characterized Hf sample in diamond anvil cells up to 120 GPa while collecting x-ray diffraction data. The phase transformations of Hf were compared in both a He pressure transmitting medium (PTM) and no PTM over several experiments. It was found that the α-Hf to ω-Hf phase transition occurs at a higher pressure during compression and lower pressure during decompression with a helium (He) PTM compared to using no PTM. There was little difference in the ω-Hf to β-Hf phase transition pressure between the He PTM and no PTM. The equation of state was fit for all three phases of Hf and under both PTM and no-PTM.
Temperature tunable flexible photo absorbers based on near-infrared 1D photonic crystal hybridized W-doped VO2 nanostructures
Authors: Singh Dipti Umed , Narayanan Remya 
Published: October 2021

Abstract
Vanadium dioxide is a potential candidate for energy efficient smart windows and have crystalline phase transition temperature (T
c) at 68 °C. So far, literatures mainly emphasis on different synthetic strategies of tungsten doped VO2 which is a most effective dopant to reduce T
c of VO2 to near room temperatures. Until now, there is no report shows the incorporation of flexible 1D photonic crystals as spectrally selective, temperature tunable device to control the changes in optical transmission modulations of W-VO2 nanostrtcures, especially in the near IR region for smart window application. W-doped VO2 with various tungsten contents were synthesized with a facile hydrothermal route. We found that, with 1.1 at% of tungsten doping in intrinsic VO2, the metal to insulator transition temperature is brought down to 37 °C from 68 °C. IR transmission of VO2 thin film can be reduced from 70% to 40% around room temperature, after doping. Significant absorption enhancement has been observed for both VO2 and W-doped VO2 films, deposited over tunable SiO2/Ta2O5 based distributed Bragg reflector (DBR) fabricated over flexible PET (poly-ethylene terephthalate) substrates. On depositing VO2 over ∼70% reflecting DBR, optical transmission is reduced to ∼15% from 35% while the temperature varies to 380 K from 300 K in IR regime. Number of stacks plays a crucial role for effective IR extinctions. A high quality DBR is fabricated by increasing no. of stacks from 4 to 7, with optical transmission of DBR reduced to nearly 5% in stop band. However, with 1.1 at% of W-VO2 over such 95% reflecting flexible DBR, optical transmission vanishes nearly, around room temperature itself in the stop bands of that DBR, which clearly indicates the significant absorption enhancement. W-VO2/DBR hybrid can substantially modulate the solar heat flux and also imbuing DBR over flexible PET substrates offers retrofitting of the existing windows for energy economy. Thus these structures have promising potential applications for optical devices and practical design for smart windows.
Geant4-DNA modeling of nanodosimetric quantities in the Jet Counter for alpha particles
Authors: Pietrzak Marcin , Mietelska Monika , Bancer Aleksandr , Rucinski Antoni , Brzozowska Beata 
Published: October 2021

Abstract
The purpose of this work was to validate the calculation accuracy of nanodosimetric quantities in Geant4-DNA track structure simulation code. We implemented the Jet Counter (JC) nanodosimeter geometry in the simulation platform and quantified the impact of the Geant4-DNA physics models and JC detector performance on the ionization cluster size distributions (ICSD). ICSD parameters characterize the quality of radiation field and are supposed to be correlated to the complexity of the initial DNA damage in nanoscale and eventually the response of biological systems to radiation. We compared Monte Carlo simulations of ICSD in JC geometry performed using Geant4-DNA and PTra codes with experimental data collected for alpha particles at 3.8 MeV. We investigated the impact of simulation and experimental settings, i.e., three Geant4-DNA physics models, three sizes of a nanometer sensitive volume, gas to water density scaling procedure, JC ion extraction efficiency and the presence of passive components of the detector on the ICSD and their parameters. We found that ICSD in JC geometry obtained from Geant4-DNA simulations in water correspond well to ICSD measurements in nitrogen gas for all investigated settings, while the best agreement is for Geant4-DNA physics option 4. This work also discusses the accuracy and robustness of ICSD parameters in the context of the application of track structure simulation methods for treatment planning in particle therapy.
Effects of frequency on bubble-cloud behavior and ablation efficiency in intrinsic threshold histotripsy
Authors: Edsall Connor , Ham Emerson , Holmes Hal , Hall Timothy L , Vlaisavljevich Eli 
Published: October 2021

Abstract

Objective. Histotripsy is a non-thermal focused ultrasound ablation method that destroys tissue through the generation of a cavitation bubble cloud. Previous work studying intrinsic threshold histotripsy has shown that dense bubble clouds can be formed by a single-cycle pulse when the negative pressure exceeds an intrinsic threshold of ∼25–30 MPa, with the ablation efficiency dependent upon the size and density of bubbles within the cloud. This work investigates the effects of frequency on bubble-cloud behavior and ablation efficiency in intrinsic threshold histotripsy. Approach. A modular transducer was used to expose agarose tissue phantoms to 500 kHz, 1 MHz, or 3 MHz, histotripsy pulses. Optical imaging was used to measure the bubble-cloud dimensions, bubble density, and bubble size. The effects of frequency on ablation efficiency were also investigated by applying histotripsy to red blood cell (RBC) phantoms. Main results. Results revealed that the bubble-cloud size closely matched theoretical predictions for all frequencies. The bubble density, which is a measure of the number of bubbles per unit area, was shown to increase with increasing frequency while the size of individual bubbles within the cloud decreased at higher frequencies. Finally, RBC phantom experiments showed decreasing ablation efficiency with increasing frequency. Significance. Overall, results demonstrate the effects of frequency on histotripsy bubble-cloud behavior and show that lower frequency generates more efficient tissue ablation, primarily due to enhanced bubble expansion.
Axial momentum gains of ions and electrons in magnetic nozzle acceleration
Authors: Emoto Kazuma , Takahashi Kazunori , Takao Yoshinori 
Published: October 2021

Abstract
Fully kinetic simulations of magnetic nozzle acceleration were conducted to investigate the axial momentum gains of ions and electrons with electrostatic and Lorentz forces. The axial momentum gains per ion and electron are directly calculated from the kinetics of charged particles, indicating that electrons in the magnetic nozzle obtain the net axial momentum by the Lorentz force, even though they are decelerated by the electrostatic force. Whereas ions are also accelerated by the electrostatic force, the axial momentum gain of electrons increases significantly with increasing magnetic field strength and becomes dominant in the magnetic nozzle. In addition, it is clearly shown that the axial momentum gain of electrons is due to the electron momentum conversion from the radial to the axial direction, resulting in a significant increase in the thrust and exhaust velocity.
Fast state detection in F1-ATPase rotation enhanced by theory of mixed states and external torque
Authors: Le Luan Q , Volkán-Kacsó Sándor 
Published: October 2021

Abstract
During brief 120° transitions between long catalytic dwells, single F1-ATPase molecules exhibit angular jumps that vary with rotation angles. Using the angular jump profile enables the detection of fast states in the mechano-chemical scheme of the enzyme, states that are difficult to capture from single-molecule trajectories due to the fluctuations of the imaging nanoprobe. In a previous work, a short-lived, three occupancy state was postulated from a multi-state, probabilistic theory to explain the mean angular jump profile. An assumption in the theory was that the ‘mixing’ of chemical states is negligible during jumps. In a mixing event, two subsequent angular positions recorded by the imaging apparatus belong to two different chemical states of the motor enzyme due to fast reactions within a recording frame. In this paper, we provide an enhanced method for the detection of fast states. On one hand, we show using Langevin simulations that state mixing leads to faster mean angular jump, shifting up the profile. Consequently, the improved method provides a correction to the angular position and lifetime of the postulated three-occupancy metastable state. On the other hand, we show that when F1-ATPase is subject to torques opposing rotation in hydrolysis direction, the torques shift down the dwell angles without affecting the angle-dependent reaction rates. The torques improve detection capability for the fast state by increasing dwell times which is made evident by the flattening of the mean angular jump profile within 40°–60° from the catalytic dwell. In the three-occupancy state release of ADP occurs in concert with the binding of ATP to a different site in the F1-ATPase. Similarly, in the full ATP synthase when torques are created by the proton gradient in the FO region, the release of the product ATP is presumably accelerated by the binding of ADP to a different site in the F1 domain.
In situ measurement on nonuniform velocity distribution in external detonation exhaust flow by analysis of spectrum features using TDLAS
Authors: Huang Xiao-Long , Li Ning , Weng Chun-Sheng , Kang Yang 
Published: October 2021

Abstract
Instantaneous and precise velocity sensing is a critical part of research on detonation mechanism and flow evolution. This paper presents a novel multi-projection tunable diode laser absorption spectroscopy solution, to provide a real-time and reliable measurement of velocity distribution in detonation exhaust flow with obvious nonuniformity. Relations are established between overlapped spectrums along probing beams and Gauss velocity distribution phantom according to the frequency shifts and tiny variations in components of light-of-sight absorbance profiles at low frequencies analyzed by the fast Fourier transform. With simulated optical measurement using H2O feature at 7185.6 cm−1 carried out on a phantom generated using a simulation of two-phase detonation by a two-fluid model, this method demonstrates a satisfying performance on recovery of velocity distribution profiles in supersonic flow even with a noise equivalent absorbance up to 2 × 10−3. This method is applied to the analysis of rapidly decreasing velocity during a complete working cycle in the external flow field of an air-gasoline detonation tube operating at 25 Hz, and results show the velocity in the core flow field would be much larger than the arithmetic average from traditional tunable diode laser doppler velocimetry. This proposed velocity distribution sensor would reconstruct nonuniform velocity distribution of high-speed flow in low cost and simple operations, which broadens the possibility for applications in research on the formation and propagation of external flow filed of detonation tube.
Decoding of cortex-wide brain activity from local recordings of neural potentials
Authors: Liu Xin , Ren Chi , Huang Zhisheng , Wilson Madison , Kim Jeong-Hoon , Lu Yichen , Ramezani Mehrdad , Komiyama Takaki , Kuzum Duygu 
Published: October 2021

Abstract

Objective. Electrical recordings of neural activity from brain surface have been widely employed in basic neuroscience research and clinical practice for investigations of neural circuit functions, brain–computer interfaces, and treatments for neurological disorders. Traditionally, these surface potentials have been believed to mainly reflect local neural activity. It is not known how informative the locally recorded surface potentials are for the neural activities across multiple cortical regions. Approach. To investigate that, we perform simultaneous local electrical recording and wide-field calcium imaging in awake head-fixed mice. Using a recurrent neural network model, we try to decode the calcium fluorescence activity of multiple cortical regions from local electrical recordings. Main results. The mean activity of different cortical regions could be decoded from locally recorded surface potentials. Also, each frequency band of surface potentials differentially encodes activities from multiple cortical regions so that including all the frequency bands in the decoding model gives the highest decoding performance. Despite the close spacing between recording channels, surface potentials from different channels provide complementary information about the large-scale cortical activity and the decoding performance continues to improve as more channels are included. Finally, we demonstrate the successful decoding of whole dorsal cortex activity at pixel-level using locally recorded surface potentials. Significance. These results show that the locally recorded surface potentials indeed contain rich information of the large-scale neural activities, which could be further demixed to recover the neural activity across individual cortical regions. In the future, our cross-modality inference approach could be adapted to virtually reconstruct cortex-wide brain activity, greatly expanding the spatial reach of surface electrical recordings without increasing invasiveness. Furthermore, it could be used to facilitate imaging neural activity across the whole cortex in freely moving animals, without requirement of head-fixed microscopy configurations.
Directed stimulation with interfascicular interfaces for peripheral nerve stimulation
Authors: Koppaka Smruta , Hess-Dunning Allison , Tyler Dustin J 
Published: October 2021

Abstract

Objective. Computational models have shown that directional electrical contacts placed within the epineurium, between the fascicles, and not penetrating the perineurium, can achieve selectivity levels similar to point source contacts placed within the fascicle. The objective of this study is to test, in a murine model, the hypothesis that directed interfascicular contacts are selective. Approach. Multiple interfascicular electrodes with directional contacts, exposed on a single face, were implanted in the sciatic nerves of 32 rabbits. Fine-wire intramuscular wire electrodes were implanted to measure electromyographic (EMG) activity from medial and lateral gastrocnemius, soleus, and tibialis anterior muscles. Main results. The recruitment data demonstrated that directed interfascicular interfaces, which do not penetrate the perineurium, selectively activate different axon populations. Significance. Interfascicular interfaces that are inside the nerve, but do not penetrate the perineurium are an alternative to intrafascicular interfaces and may offer additional selectivity compared to extraneural approaches.
The role of tungsten chemical state and boron on ammonia formation using N2–H2 radiofrequency discharges
Authors: Antunes R. , Marot L. , Romero-Muñiz C. , Steiner R. , Meyer E. 
Published: October 2021

Abstract
This work aims at investigating the role of tungsten and boron surfaces on ammonia production with N2–H2 radiofrequency plasmas at 3 Pa. The experiments combine the analysis of the reaction products and surface chemical environment using mass spectrometry and x-ray photoelectron spectroscopy (XPS). We show that NH3 is formed upon discharges of N2 or H2 after having exposed a tungsten (W) foil to H2 or N2, respectively. A higher amount of ammonia is formed for the N2-then-H2 case, which we explain by the larger number of Eley–Rideal reaction channels for the formation of NH
x
(s) and the lower surface diffusion barrier for adsorbed hydrogen, calculated using the density functional theory (DFT). As a result, H(s) combines with N(s) or NH
x
(s) through Langmuir–Hinshelwood at a faster rate than N(s) combines with another N(s). The amount of NH3 formed with N2–H2 discharges after conditioning the tungsten foil with H2, N2 or O2 was also investigated. We observed that this pre-conditioning plays no major role on the amount of NH3 detected with the residual gas analyser, albeit a small decrease was observed after H2 contamination. With DFT, the adsorption energies of H on WO3 and W are found to be similar, while the adsorption of N on WO3 is significantly weaker. The similar NH3 concentrations obtained with a clean and oxidized tungsten surface thus suggest that the adsorption of N does not limit the formation rate of ammonia. The production of NH3 on boron was evaluated as well. The boron surface reduced the amount of detected ammonia almost by half. On the one side, a significant amount of H2 was removed from the surface during the Ar cleaning that followed, which suggests a strong retention of hydrogen. On the other side, the XPS data reveals that nitrogen forms strong bonds with boron and impurities on the surface, regardless on whether hydrogen is previously present on the surface or in the plasma volume. The presence of hydrogen in the plasma volume, simultaneously with nitrogen or after nitrogen exposure, is nevertheless necessary for the formation of NH(s) and NH2(s). No NH3(s) was however detected with XPS. The increased retention of both hydrogen and nitrogen on the boron surface may thus hinder the formation of NH3.
Evaluation of tribological, oxidation and corrosion behavior of HVOF sprayed sustainable temperature-dependent carbon coating
Authors: Tyagi Ankit , Chourasia Shubhangi , Murtaza Qasim , Walia R S 
Published: October 2021

Abstract
To abate frictional loss, advanced coatings are vital for piston rings, thick low friction environment-friendly carbon coatings have been deposited using HVOF spray (High Velocity Oxy-fuel) technique. The COF (Coefficient of Friction) was found in the range of 0.3 to 0.45 whereas the wearing range was about 45–150 μm during the tested conditions. After wear test at high temperature, the developed coating shows that micro-hardness was increased about 11.5%, 90% reduction in residual stress, COF decreases to about 50%, and wear decreases to about 70% under test conditions. The experimental result of the conducted corrosion test illustrates that the overall measured mass loss per unit area of the as deposited sample was decreased to be about 85.7% at an exposure time of 1 h, 63.6%, at an exposure time of 3 h, and 55% at an exposure time of 5 h.
Plasma activated water prepared by different plasma sources: physicochemical properties and decontamination effect on lentils sprouts
Authors: MEDVECKÁ Veronika , OMASTA Samuel , KLAS Matej , MOŠOVSKÁ Silvia , KYZEK Stanislav , ZAHORANOVÁ Anna 
Published: October 2021

Abstract
The pulsed corona discharge (CD) generated in contact with water and directly in water, and high-power air plasma jet (APJ) were studied for production of plasma activated water (PAW). The changes of physical (pH, redox potential, conductivity, temperature) and chemical (peroxides, nitrites, nitrates concentrations) properties of treated water were investigated. The comparison of CD generated in gas/water interface and underwater configuration in the same system showed that the interaction of reactive oxygen and nitrogen species formed in ambient air in gas/water system induces different chemical processes, leading to lower pH, higher oxidation-reduction potential (ORP) and higher conductivity of PAW than in underwater discharge. High yield of peroxide was observed in both configurations. The PAW prepared by APJ exhibits high concentration of nitrites and nitrates according to supplied energy, and related significant decrease of pH and increase of ORP and conductivity after treatment. The antimicrobial effect of PAW prepared by CD and plasma jet on lentils sprouts was studied in different treatment and washing times. The APJ appears to have great efficacy on water activation resulted in strong decontamination effect. The PAW treated by APJ for 10 min led to bacterial reduction from initial 8.3 to 5.9 and 4.0 log10 CFU g−1 after 10 and 30 min of washing, respectively.
A note on the asymptotics of the Hankel determinant associated with time-dependent Jacobi polynomials
Authors: Min Chao , Chen Yang 
Published: October 2021

In 2010, Basor, Chen and Ehrhardt [J. Phys. A 43 (2010), 015204 (25 pp)] studied the (monic) time-dependent Jacobi polynomials. They proved that the diagonal recurrence coefficientαn(t)\alpha _n(t)satisfies a particular Painlevé V equation and the sub-leading coefficientp(n,t)\mathrm {p}(n,t)satisfies the Jimbo-Miwa-Okamotoσ\sigma-form of Painlevé V under suitable transformations. In the end they made some conjectures about the largennasymptotics of the associated Hankel determinant. In this note we will derive the largennasymptotics of the Hankel determinant, together with the recurrence coefficients, the sub-leading coefficient and the square ofL2L^2-norm of the time-dependent Jacobi polynomials. We will also show the relation between our problem and Heun’s differential equations.
Introduction
Authors: Ratner-Rosenhagen Jennifer 
Published: October 2021

Abstract
‘Introduction’ examines the scope and aims of American intellectual history. It shows how it is an approach to understanding the American past by way of ideas and the people who made or were moved by them. Intellectual history seeks to understand where certain persistent concerns in American thought have come from and why some ideas, which were important in the past, have faded from view. Intellectual history also concerns itself with the myriad institutions that are sites of intellectual production and dissemination. Ultimately, intellectual history invites thinking about thinking, both in the past and today. It seeks to demonstrate that thinking is where so much of the historical action is.
Modernist revolts
Authors: Ratner-Rosenhagen Jennifer 
Published: October 2021

Abstract
‘Modernist revolts’ traces the turn-of-the-twentieth-century rise of what philosopher John Dewey called a “new intellectual temper”: modernism. It was at this time that the idea of the intellectual enters American English as a term to identify a new type of modern professional thinker. To be an intellectual meant accepting responsibility to help other Americans accept a modernizing world of social change and dissonance while finding new grounds to negotiate their differences. The modernist thought they advocated came in a variety of forms: from new religious thought and philosophical pragmatism to progressivism and cultural pluralism.