bluuebunny/crossref_metadata_2025 huggingface dataset:
Everyday Race: Millennials, Generation Z, and the Census
Authors: Cox Jonathan M. , Headley Vernon T. , Johnson Kristal S.
Published: April 2023

The census is a central feature of U.S. governance, providing important information regarding the U.S. population used to determine legislative representation and the allocation of federal funding. The count also involves a measure of race and ethnicity, however the sociopolitical construction of race means census categories have shifted throughout history. Existing data highlight how current classifications do not fully capture the identities of different groups; however, less is known about the views of young adults. Utilizing interview and journal data wherein 84 college students from the Millennial and Generation Z cohorts were asked to reflect on the 2010 and 2020 census race questions, our findings reveal a major gap between census classification and everyday experiences with racial categorization. Our study provides meaningful insights into how young adults think about the census race and ethnicity categories, with implications for future research and census collection.
OsWRKY10 extensively activates multiple rice diterpenoid phytoalexin biosynthesis genes to enhance rice blast resistance
Authors: Wang Liping , Fu Jingye , Shen Qinqin , Wang Qiang
Published: April 2023

Phytoalexin is the main chemical weapon against pathogens in plants. Rice (Oryza sativa L.) produces a number of phytoalexins to defend against pathogens, most of which belong to the class of diterpenoid phytoalexins. Three biosynthetic gene clusters (BGCs) and a few non‐BGC genes are responsible for rice diterpenoid phytoalexin biosynthesis. The corresponding regulatory mechanism of these phytoalexins in response to pathogen challenges still remains unclear. Here we identified a transcription factor, OsWRKY10, which positively regulates rice diterpenoid phytoalexin biosynthesis. Knockout mutants of OsWRKY10 obtained by CRISPR/Cas9 technology are more susceptible to Magnaporthe oryzae infection, while overexpression of OsWRKY10 enhances resistance to rice blast. Further analysis revealed that overexpression of OsWRKY10 increases accumulation of multiple rice diterpenoid phytoalexins and expression of genes in three BGCs and non‐BGC genes in response to M. oryzae infection. Knockout of OsWRKY10 impairs upregulation of rice diterpenoid phytoalexin biosynthesis gene expression by blast pathogen and CuCl2 treatment. OsWRKY10 directly binds to the W‐boxes or W‐box‐like elements (WLEs) of rice diterpenoid phytoalexin biosynthesis gene promoters to regulate gene expression. This study identified an extensive regulator (OsWRKY10) with broad transcriptional regulatory effects on rice diterpenoid phytoalexin biosynthesis genes, providing insight into the regulation of chemical defense to improve disease resistance in rice.
Cold storage of whole blood in an additive solution containing apoptotic and necrotic inhibitors
Authors: Reddoch‐Cardenas Kristin M. , McIntosh Colby , Barrera Gema , Bynum James A.
Published: April 2023

Background

Whole blood (WB) reigns superior to component therapy for the treatment of hemorrhagic shock on the battlefield. Though cold storage of WB offers a shelf life of 21 to 35 days, storage lesions and the potential for blood wastage remain. Storing WB in an additive solution (AS) containing apoptotic inhibitors may help preserve blood cell viability and improve blood quality over extended cold storage.

Study Design and Methods

Non‐leukoreduced WB was obtained from healthy individuals and dosed with: AS, AS+Necrostatin‐1 (AS+N1), AS+Boc‐D‐fmk (AS+B; apoptosis inhibitor), AS+Q‐VD‐OPh (AS+Q; apoptosis inhibitor), and Control (0.9% saline). Blood bags were kept refrigerated (1°–6°C) for 21 days. Bags were tested on days 0, 7, 14, and 21 for complete blood count, metabolism, clot formation, aggregation function, platelet activation, and red blood cell quality.

Results

Platelet count was better preserved in all AS‐containing samples. All groups displayed increased glucose consumption and lactate production with storage. Furthermore, all groups displayed a similar decline in clot strength (max amplitude) over the 21‐day storage period. Bags that received AS displayed greater preservation of GPIIb expression and lower phosphatidylserine exposure. P‐selectin expression was increased in all AS groups.

Discussion

Treatment of hemorrhagic shock with WB transfusion is logistically simpler than component therapy. Results from our study suggest that refrigerated WB stored with an AS containing apoptotic and necrotic inhibitors helps better preserve platelet count but does not improve platelet function. The future development of WB ASs is warranted to optimize both platelet quality and hemostatic function.
A Python Implementation of a Robust Multi-Harmonic Balance With Numerical Continuation and Automatic Differentiation for Structural Dynamics
Authors: S. Martins Tiago , Trainotti Francesco , Zwölfer Andreas , Afonso Frederico
Published: April 2023

This work presents a tool that performs simulations in nonlinear vibration analysis. It can be used to appraise the structure's functionality and to determine the loading effects. Oscillations are fundamental in nature, appearing in practical engineering applications. General nonlinear problems hardly have analytical solutions, requiring sophisticated techniques to reach approximate solutions. This toolbox is an open-source Python implementation of a robust multiharmonic balance with predictor–corrector numerical continuation, Newton–Raphson root-solver, and forward automatic differentiation with dual numbers, which is a novelty. It shows promising converging robustness, especially in the construction of frequency response curves, when dealing with polynomial as well as sharp nonlinearities, such as dry-friction.
Numerical Investigation of Conjugate Natural Convection From a Vertical Cylindrical Open Cavity
Authors: Mohamad Shafiq , Rout Sachindra Kumar , Senapati Jnana Ranjan , Sarangi Sunil Kumar
Published: April 2023

An extensive numerical analysis is performed on a vertical cylindrical open cavity made of aluminum with varying thicknesses to study conjugate natural convection. The key purpose of this study is to evaluate the effect of cylinder wall thickness on natural convection at the outer wall of the cylinder, which is coupled to the inner cylinder wall that has a constant temperature of 450 K and the ambient air which temperature is 300 K. The Navier–Stokes equations, continuity equation, and energy equations are solved numerically. The finite volume method is applied in the computational domain that includes the vertical cylindrical open cavity by using ansys-fluent 18 to specify the properties of flow and exchange of thermal energy. A couple of pertinent parameters are used for the numerical investigation like Rayleigh number within laminar regime (within range 104–108), aspect ratio (undefined proportion of length to diameter of the cylinder (L/D)) of the vertical cylindrical open cavity (2, 4, 6, 8, 10), and cylinder wall thickness (0, 1, 2, 3, 4 mm). This study presents the velocity vector field and thermal plume contours. An approximate Nusselt number to Rayleigh number equation is developed for the vertical cylindrical cavity within the range of Rayleigh numbers addressed by this work.
Positioning Accuracy Prediction and Tolerance Allocation of Cycloid Reducers Based on a BDTCA Model
Authors: Wang Xincheng , Li Luyang , Ye Jianfeng , Yang Xuefeng , Wang Huaming , He Xigang
Published: April 2023

The reliability of the prediction model and test scheme for the positioning accuracy of the cycloid reducer is very important. This paper proposes an efficient bidirectional drive tooth contact analysis (BDTCA) model that can simultaneously analyze the forward transmission error (TE), the reverse TE, and the global lost motion (GLM) of a cycloid drive, considering a variety of manufacturing and assembly errors (including pin assembly error). The results of the BDTCA case studies show that the sensitivity of the pin radius error to the GLM considering pin assembly error is twice that of the sensitivity without considering pin assembly error. Therefore, the influence of pin assembly error on the GLM cannot be ignored. The equivalent error model for BDTCA is established based on Latin hypercube sampling and template measurement, and the positioning accuracy of 50,000 reducer virtual prototypes is predicted. According to the positioning accuracy requirements, the tolerance allocation is optimized by using the discrete particle swarm optimization algorithm, and the qualified rate after optimization is significantly improved. A bidirectional drive test (BDT) scheme is proposed according to the BDTCA model. By comparing with the traditional hysteresis curve test, the superiority of the BDT scheme and the rationality of the tolerance allocation optimization are proved. The sensitivity of the pin radius error to the GLM is obtained through a comparison BDT, which verifies the correctness of the BDTCA model considering pin assembly error. This BDTCA model provides more reliable theoretical guidance for the design and manufacture of cycloid reducers.
Heat Transfer Enhancement in Laminar Pipe Flow Using Al2O3–Water Nanofluid and Twisted Tape Inserts
Authors: Bairagi Santinath , Roy Ranendra , Mandal Bijan Kumar
Published: April 2023

In this study, an attempt has been made to carry out a numerical investigation using water-based Al2O3 nanofluid, flowing through a circular tube under constant inlet temperature and constant heat flux conditions in the laminar flow regime. The water-based Al2O3 nanofluid is used in a circular plain tube first, and then, this process is repeated for the same tube fitted with twisted tape inserts of twist ratio 1.85 at Reynolds numbers ranging from 680 to 2030. For the numerical analysis, ANSYS FLUENT is used to solve three-dimensional conservation equations of mass, momentum, and energy. The simulated results indicate that when twisted tape is used, heat transfer rates increase significantly with the use of nanofluid. In the case of nanofluid with the plain tube, only 10–24% enhancement in heat transfer rate is noted. On the other hand, almost 27–45% increase in heat transfer is observed compared to that with only water when twisted tape is inserted into it. Also, the friction factor increases as the nanoparticle volume fraction increases. However, the effect on the heat transfer rate is more significant than that on the friction factor. The best thermohydraulic performance factor achieved is 2.1 using nanofluids with a 5% volume fraction of the nanoparticles at a high Reynolds number when twisted tape is also inserted.
Thermo-Economic Comparative Study and Multi-Objective Optimization of Supercritical CO2-Based Mixtures Brayton Cycle Combined With Absorption Refrigeration Cycle
Authors: Ma Ya-Nan , Hu Peng
Published: April 2023

In this paper, a novel system based on the combination of a supercritical recompression Brayton cycle (SRBC) and LiBr-H2O absorption refrigeration cycle (ARC) is proposed, in which ARC utilizes the waste heat of SRBC for cooling and further reduces the main compressor inlet temperature. The potential of using xenon and krypton as additives for the supercritical CO2 Brayton cycle is explored via comparative analysis. The results show that CO2/Krypton is more suitable to be the working fluid of the combined system because of its higher thermal efficiency and lower costs. The effects of the operating parameters and mass fraction of krypton on the thermo-economic performance of the combined system are discussed. Multi-objective optimization is applied to simultaneously optimize the thermal efficiency and total product unit cost of the system. Compared with the stand-alone cycle, the combined system can improve the cycle efficiency over a wide temperature range. The exergy efficiency of SRBC/ARC using CO2/Krypton (0.64/0.36) increased from 0.638 to 0.688, from 0.653 to 0.665, and from 0.586 to 0.646 at ambient temperature T0 = 10, 25, 35 °C, respectively, increasing by 7.84%, 1.84%, and 10.24% compared with that of SCO2RBC. The combined system will achieve its full potential when the critical temperature of the working fluid is close to the ambient temperature.
Reduction of Pressure Pulsation for Pump-Turbine by Variable Speed Operation
Authors: Li Yulan , Yang Weijia , Huang Yifan , Ma Weichao , Zhao Zhigao , Yang Jiebin , Cheng Yongguang , Qian Zhongdong , Yang Jiandong
Published: April 2023

Variable speed operation has emerged as a key direction in the development of pumped storage technology. Maintaining pressure pulsation within the control range is particularly critical for ensuring operational safety of variable-speed pumped storage plants (VSPSPs). However, there is limited research on the relationship between pressure pulsation for pump-turbine and variable speed operation. This paper presents amplitude distribution diagrams of pressure pulsation, obtained from processing model test results of a real VSPSP. Different conditions of variable speed operation are simulated by a numerical model to analyze the influence of operating trajectory on pressure pulsation, and the intensity of pressure pulsation is quantitatively evaluated. According to the results, when the initial speed or speed command increases, the trajectory passes through more regions with high-amplitude pressure pulsation and gradually moves toward the S-shaped region, leading to pressure oscillations. When speed command reduces, maximum pressure pulsation at the volute inlet and in the draft tube can be reduced by 82.18% and 63.24% at most, and the evaluation score can be increased by 28.77%. The findings of this study can offer theoretical guidance for operating VSPSPs.
Fatigue Damage Study of Steel–Aluminum Friction Stir Welding Joints Based on Equivalent Damage Model
Authors: Wu Haifeng , Xu Sha , Chen Hao , Yang Yali , Gao Kun , Li Yongfang
Published: April 2023

An equivalent damage model was established to study the fatigue damage behavior of steel–aluminum friction stir welding (FSW) joints. Internal defects of friction stir welding joint under various cyclic loading stages were observed by X-ray microcomputed tomography (X-CT). For the characteristics of defects of the steel–aluminum FSW joints, a simplified method of defects considering key parameters is proposed, and then, the defect model is established. The FSW joint model was established based on the steel–aluminum boundary contour identified by using image processing techniques. Based on the defect model and the FSW joint model, the equivalent damage model was developed. The equivalent damage model was subjected to finite element analysis and compared with the test using strain amplitude as the damage variable. The equivalent damage model can be used to assess fatigue damage in steel–aluminum FSW joints, which provides some theoretical basis for fatigue life prediction.
Quantum routing of information using chiral quantum walks
Authors: Bottarelli Alberto , Frigerio Massimo , Paris Matteo G. A.
Published: April 2023

We address routing of classical and quantum information over quantum network and show how to exploit chirality (directionality) to achieve nearly optimal and robust transport. In particular, we prove how continuous-time chiral quantum walks over a minimal graph are able to model directional transfer of information over a network. At first, we show how classical information, encoded onto an excitation localized at one vertex of a simple graph, may be sent to any other chosen location with nearly unit fidelity by tuning a single phase. Then, we prove that high-fidelity transport is also possible for coherent superpositions of states, i.e., for routing of quantum information. Furthermore, we show that by tuning the phase parameter, one obtains universal quantum routing, i.e., independent on the input state. In our scheme, chirality is governed by a single phase, and the routing probability is robust against fluctuations of this parameter. Finally, we address characterization of quantum routers and show how to exploit the self-energies of the graph to achieve high precision in estimating the phase parameter.
Study of process parameters and characteristics properties of W coatings deposited by rf plasma sputtering
Authors: Vassallo Espedito , Pedroni Matteo , Aloisio Marco , Minelli Daniele , Nardone Antonio , Chen Hao , Pietralunga Silvia Maria , Stinchelli Andrea , Di Fonzo Fabio
Published: April 2023

Tungsten coatings were deposited on silicon substrates by radio frequency (rf) magnetron sputtering from a metallic target in Ar atmosphere. The process parameters during the sputtering process were evaluated by a Langmuir probe, particularly, the electron density and electron temperature were measured by changing the rf power and gas pressure. The morphological and structural properties of the coatings were studied as a function of the pressure. Significant correlations were found between process parameters and characteristics properties of W coatings. The influence of deposition parameters on electrical properties was investigated. The electrical resistivity of the coatings was increased from 1.3 × 10−6 to 3 × 10−5 Ω m as the pressure increased as well.
Design of a large nonevaporable getter pump for the full size ITER beam source prototype
Authors: Sartori E. , Siragusa M. , Berton G. , Cavallini C. , Dal Bello S. , Fadone M. , Grando L. , Marcuzzi D. , Rizzetto D. , Serianni G. , Sonato P. , Zaupa M. , Dinh F. , Ferrara A. , Maccallini E. , Mura M. , Siviero F. , Toigo V.
Published: April 2023

An improvement for the vacuum system of the multidriver radio frequency (RF) prototype negative ion source SPIDER has been developed, to allow operating at high RF power, while minimizing the breakdown probability on the outside of the plasma source. A first-of-its-kind large nonevaporable getter (NEG) pump, based on a modular design of 384 cartridges totaling about 350 kg of ZAO® alloy (composed by Zr-Ti-V-Al) with an installed pumping speed at a room temperature of 330 m3/s for hydrogen, will complement the existing pumping system, based on eight cryogenic pumps and four turbomolecular pumps totaling about 90 m3/s in hydrogen. The vessel pressure during absorption is expected to be between 20 and 40 mPa, while during the getter regeneration, the peak operating pressure will be around 2 Pa. The NEG pump will use an additional vessel module, with integrated thermal shields to protect the in-vessel components during activation and regeneration of the pump, to be carried out at temperatures in the range of 550–600 °C. Integrated thermal analyses were carried out to verify the low heat load on pre-existing in-vessel components with a low limit of acceptable temperature, and to provide boundary conditions for the mechanical verifications of the pump structure. The scenario of cyclic hydrogen load was calculated considering the SPIDER operation modes, the expected gas throughput, and the cumulated load to the pump, to determine the regeneration temperature and auxiliary pumping necessary to make the regeneration duration compatible with the high availability of the system. The upgrade of the auxiliary pumping system is also described, as well as the mitigation of air or water exposure risk during regeneration of the NEG pump.
Atomic layer deposition of MoOx thin films using Mo(iPrCp)2H2 and O3
Authors: Hendrix Ethan , Garland Ben M. , Vemuri Vamseedhara , Strandwitz Nicholas C.
Published: April 2023

This work studied the growth of molybdenum oxide thin films with thermal atomic layer deposition (ALD) using Mo(iPrCp)2H2 and O3 as precursors. Growth parameters were determined by varying growth temperature and precursor dose times. ALD growth was exhibited in a temperature range of 100–200 °C. The growth per cycle ranged from 1.3 to 1.7 Å/cycle with a standard uniformity parameter of <5%. Attempts to grow films using H2O as an oxygen source showed no significant growth. Film properties were measured using spectroscopic ellipsometry, x-ray reflectivity, x-ray diffraction, x-ray photoelectron spectroscopy, and infrared spectroscopy.
Epitaxial growth of atomically thin Ga2Se2 films on c-plane sapphire substrates
Authors: Yu Mingyu , Murray Lottie , Doty Matthew , Law Stephanie
Published: April 2023

Broadening the variety of two-dimensional (2D) materials and improving the synthesis of ultrathin films are crucial to the development of semiconductor industry. As a state-of-the-art 2D material, Ga2Se2 has attractive optoelectronic properties when it reaches the atomically thin regime. However, its van der Waals epitaxial growth, especially for atomically thin films, has seldom been studied. In this paper, we used molecular beam epitaxy to synthesize Ga2Se2 single-crystal films with a surface roughness down to 1.82 nm on c-plane sapphire substrates by optimizing the substrate temperature, Se:Ga flux ratio, and growth rate. Then, we used a three-step mode to grow Ga2Se2 films with a thickness as low as three tetralayers and a surface roughness as low as 0.61 nm, far exceeding the performance of direct growth. Finally, we found that surface morphology strongly depends on the Se:Ga flux ratio, and higher growth rates widened the suitable flux ratio window for growing Ga2Se2. Overall, this work advances the understanding of the vdW epitaxy growth mechanism for post-transition metal monochalcogenides on sapphire substrates.
Impact of photovoltaic effect on performance enhancement of triboelectric nanogenerator for energy harvesting applications
Authors: Kumar Shailendra , Jha Rajesh Kumar , Chitnis Ujjwal , Singh Shalini , Anand Jay Krishna , Roy Swapan Kumar , Goswami Ankur
Published: April 2023

The photo-induced triboelectric nanogenerator (PTENG) has been explored as new generation energy technology, which is enabled by coupling triboelectric and photo-induced charge carriers. PTENG shows a dual work mechanism that is attributed to the synergetic outcome of the photovoltaic and triboelectric effects. This study aims to provide a new strategy for triboelectric nanogenerator devices to achieve high output performance for various smart electronic device applications. Aluminum and n-type silicon were chosen as two different materials for triboelectric measurements. Different techniques were adopted to obtain triboelectric output parameters through the in-house developed triboelectric setup. AFM and Kelvin probe force microscopy imaging techniques were employed to obtain surface roughness and to measure the change in surface potential under the illumination of red (630 nm) laser light. A significant improvement in surface potential of around 40 mV was observed under laser illumination. Triboelectric characterization has been performed to obtain open circuit voltage (VOC) and short circuit current (ISC) with and without light illumination at different speeds of the motor. VOC and Isc were found to be 0.8 V and 2.2 nA, respectively, at 50 rpm speed without any illumination, which was further enhanced to 1.8 V and 5.5 nA, respectively, under the influence of laser light illumination. An increase in the motor speed to 100 rpm results in higher VOC (2.4 V) and higher ISC (3.4 nA) as compared to 50 rpm at no illuminating condition. However, it enhances to 3.4 V and 6.0 nA in illuminating conditions. This is attributed to the generation of charge carrier due to triboelectrification, which is further enhanced because of the photovoltaic effect wherein the generation of electron-hole pair occurs due to the shining of light on the side of semiconductors. These synergetic effects have tremendous potential in sustainable energy harvesting.
Thermal atomic layer etching of cobalt using sulfuryl chloride for chlorination and tetramethylethylenediamine or trimethylphosphine for ligand addition
Authors: Murdzek Jessica A. , Lii-Rosales Ann , George Steven M.
Published: April 2023

Thermal atomic layer etching (ALE) of cobalt was developed using sulfuryl chloride (SO2Cl2) for chlorination and either tetramethylethylenediamine (TMEDA) or trimethylphosphine (PMe3) for ligand addition. In situ quartz crystal microbalance (QCM) measurements were used to monitor the thermal ALE of cobalt using the SO2Cl2/TMEDA and SO2Cl2/PMe3 processes. For every SO2Cl2 exposure, there was a mass gain during chlorination. For every TMEDA or PMe3 exposure, there was a mass loss during ligand addition. The result was a net removal of cobalt during each chlorination/ligand-addition reaction cycle. Average etch rates determined from QCM measurements for the SO2Cl2/TMEDA process at 175, 200, 225, 250, 275, and 300 °C were 0.62 ± 0.41, 1.35 ± 0.64, 2.31 ± 0.91, 6.43 ± 1.31, 10.56 ± 2.94, and 7.62 ± 4.87 Å/cycle, respectively. These etch rates were corroborated using x-ray reflectivity (XRR) studies on cobalt thin films on silicon coupons. Quadrupole mass spectroscopy analysis also revealed that the cobalt etch product from TMEDA exposures on CoCl2 powder was CoCl2(TMEDA). The SO2Cl2/TMEDA process could remove the surface chloride layer formed by each SO2Cl2 exposure with one TMEDA exposure. In contrast, the SO2Cl2/PMe3 process required 20–40 individual PMe3 exposures to remove the surface chloride layer formed from each SO2Cl2 exposure at 130–200 °C. An increasing number of PMe3 exposures were needed as the temperature decreased below 130 °C. The etch rates for the SO2Cl2/PMe3 process with multiple PMe3 exposures were 2–4 Å/cycle as determined by the QCM and XRR studies. For both the SO2Cl2/TMEDA and SO2Cl2/PMe3 processes, the etch rate was determined by the amount of CoCl2 created during the SO2Cl2 exposure. Thicker surface CoCl2 layers from larger SO2Cl2 exposures resulted in higher Co etch rates that could exceed one crystalline unit cell length. Atomic force microscopy measurements determined that the cobalt surface roughness decreased after Co ALE with the SO2Cl2/TMEDA process. In contrast, the cobalt surface roughness increased after Co ALE with the SO2Cl2/PMe3 process. The chlorination and ligand-addition mechanism should be generally applicable for metal ALE for metals that form stable chlorides.
Field electron emission and field ion microscope images of layered material MoS2
Authors: Saito Yahachi
Published: April 2023

Field emission microscopy and field ion microscopy (FEM and FIM) of two-dimensional layered material, MoS2, were carried out. MoS2 field emitters were prepared by mechanical peeling of a single crystal and by deposition of MoS2 suspension. FEM exhibited an array of elongated broad spots, and the corresponding FIM images presented patterns consisting of streaked spots and split spots (double spots), depending on electric voltages applied to the emitter. Since the probability of field ionization of imaging gas atoms (Ne gas was used in the present study) is governed by both field strength near surface atomic sites and accessible vacant electronic states, these patterns reflect the atomic site and/or spatial distribution of unoccupied electronic orbitals at the edges of MoS2 layers.
Improvement of antibacterial activity and mechanical properties of titanium alloy by TiAlN/Ag gradient multilayer coatings
Authors: Fang Xianglin , Tu Rong , Liu Jiawei , Dai Honglian , Zheng Long , Zhu Shaobo , Zhang Song , Goto Takashi
Published: April 2023

Silver coating has an excellent antibacterial activity but low mechanical properties, e.g., microhardness. In order to improve simultaneously the antibacterial activity and surface hardness of titanium alloys, TiAlN/Ag multiple coatings with different gradient distributions in thickness were prepared on titanium alloys by unbalanced magnetron sputtering. The coatings with gradient thickened TiAlN–Ag cosputtered upper layers had a much stronger antibacterial activity, 99.82% in antiseptic Escherichia coli, than those with the gradient thinned upper layers. With increasing gradient cycles of the multiple coatings, the antibacterial activity decreased, whereas the hardness increased. The alternate growth of TiAlN and TiAlN–Ag layers may repeatedly provide an excellent comprehensive antibacterial activity (99.23% for Escherichia coli) and hardness (two times TC4 alloy) for a long term.
Angular distribution of titanium ions and neutrals in high-power
impulse magnetron sputtering discharges
Authors: Renner M. , Fischer J. , Hajihoseini H. , Gudmundsson J. T. , Rudolph M. , Lundin D.
Published: April 2023

The angular dependence of the deposition rates due to ions and neutrals in high-power impulse magnetron sputtering (HiPIMS) discharges with a titanium target were determined experimentally using a magnetically shielded and charge-selective quartz crystal microbalance (or ionmeter). These rates have been established as a function of the argon working gas pressure, the peak discharge current density, and the pulse length. For all explored cases, the total deposition rate exhibits a heart-shaped profile and the ionized flux fraction peaks on the discharge axis normal to the cathode target surface. This heart-shaped pattern is found to be amplified at increasing current densities and reduced at increased working gas pressures. Furthermore, it is confirmed that a low working gas pressure is beneficial for achieving high deposition rates and high ionized flux fractions in HiPIMS operation.
Effect of the kinetic energy on particle ejection process from carbon nanotubes bombarded by kilo-electron-volt C60
Authors: Hrabar Sviatoslav , Kański Michał , Louerdi Soukaina , Postawa Zbigniew
Published: April 2023

Molecular dynamics computer simulations are employed to investigate processes leading to particle ejection from single-wall carbon nanotubes bombarded by keV C60 projectiles. The effect of the primary kinetic energy, the incidence angle, and the nanotube diameter on the ejection process is studied. Armchair nanotubes with diameters of 3.26, 5.4, and 8.2 nm are tested. C60 projectiles bombard these targets with kinetic energy between 3 and 50 keV and the angle of incidence ranging between 0° and 75°. The particle ejection yield is a result of the interplay between the amount of kinetic energy available for breaking interatomic bonds, the size of the bombarded area, and the size and form of projectiles hitting this area. Much of the initial kinetic energy is dissipated in the nanotubes as waves, especially for low-energy impacts. Computer simulations are used to find the optimal conditions leading to the gentle ejection of unfragmented organic molecules adsorbed on nanotube substrates. This knowledge may be helpful in the potential application of nanotube substrates in secondary ion mass spectrometry or secondary neutral mass spectrometry.
Polyacrylonitrile nanofibrous membrane composited with zeolite imidazole skeleton-8 and silver nanoclusters for efficient antibacterial and emulsion separation
Authors: Chen Huaxiang , Zhou Hao , Chen Mingchao , Quan Yan , Wang Chenglong , Gao Yujie , Wu Jindan
Published: April 2023

Oily wastewater discharged by industrial development is an important factor causing water pollution. Membrane separation technology has the advantages of low cost, simple operation, and high efficiency in the treatment of oily wastewater. However, membrane materials are easily eroded by microorganisms during long-term storage or use, thereby resulting in reduced separation efficiency. Herein, a zeolite imidazole skeleton-8@silver nanocluster composite polyacrylonitrile (ZIF-8@AgNCs/PAN) nanofibrous membrane was fabricated by electrospinning and in situ growth technology. The surface chemistry, morphology, and wettability of the composite membranes were characterized. The carboxyl groups on the surface of hydrolyzed PAN nanofibers, which can be complexed with zinc ions (Zn2+), are utilized as growth sites for porous metal organic frameworks (ZIF-8). Meanwhile, AgNCs are loaded into ZIF-8 to achieve stable hybridization of ZIF-8@AgNCs and nanofibers. The loading quantity of ZIF-8@AgNCs, which can dominantly affect the surface roughness and the porosity of the membranes, is regulated by the feeding amount of AgNCs. The ZIF-8@AgNCs/PAN membrane achieves effective oil-water separation with high separation efficiency toward petroleum ether-in-water emulsion (98.6%) and permeability (62 456 ± 1343 Lm−2 h−1 bar−1). Furthermore, the ZIF-8@AgNCs/PAN membrane possesses high antibacterial activity against Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus), which is beneficial for the long-term storage and use of the membrane.
The efficiency of ultrasonic glymphatic manipulation-based intrathecal drug delivery depends on the physiological states
Authors: Xiao Haijun , Shrestha Binita , Gallegos Gabriel , Kalensky Nuala , Patel Dhruv , Bocchetta Maurizio , Porter Tyrone M. , Aryal Muna
Published: April 2023

Recently, for the first time, we discovered that brain-wide application of low-pressure transcranial focused ultrasound can be used to enhance the parenchymal penetration of intrathecally administered imaging agents to a large portion of the brain through the glymphatic pathway. This proof-of-concept study only investigated the delivery efficiency in fully anesthetized animals (2.5% isoflurane). Here, we aim to determine how different anesthetic conditions affect the delivery efficiency as the glymphatic system is altered by the physiological states. We assigned three rat experimental groups: heavy-3% isoflurane (n = 4), moderate-2.5% isoflurane (n = 4), and light-1.5% isoflurane (n = 5), co-delivered two different-sized imaging tracers intrathecally (IRDye + trypan blue, IRDye labeled IgG antibody + trypan blue), and exposed ultrasound (650 kHz, 0.2 MPa for 10 min). We measured heart rate, respiratory rate, oxygen level, perfusion, and body temperature during the test and imaged the ex vivo brain using an optical imaging system. We observed that the distribution of the delivered agents in the brain parenchyma is higher in light anesthetic groups as compared to moderate and higher ones, and it depends on the molecular size of the agents as well. Future work is to increase the number of animals in each group, perform statistical analysis to confirm the preliminary findings, and determine the delivery efficacy of the technique on metastatic cancer model. M. Aryal et al., J Control Release (2022), PMID:35798095.
Comparative evaluation of omnidirectional and directional micro-electromechanical system microphone performance
Authors: Stalder Carly , Leahy Stephane
Published: April 2023

As the need for directionality becomes a key requirement in audio applications, directional microphones have begun to enter the micro-electromechanical system (MEMS) design and market space, and their performance is approaching that of top-of-the-line omnidirectional MEMS microphones. This presentation examines and compares the performance limitations for both types of MEMS microphones and suggests more comprehensive methods of characterization that allow the qualities of directional MEMS microphones to be fully captured. Mechanical thermal noise caused by Brownian motion of air particles, measured with a laser Doppler vibrometer system, are shared and discussed for a variety of microphones and test structures. Parameters such as signal-to-noise ratio, total harmonic distortion, and frequency response are re-examined in order to capture the value of a microphone that exhibits directional behavior. Insights and suggestions are made for improvement and future work.
Effect of hearing protection attenuation on impulse insertion loss and kurtosis
Authors: Murphy William J. , Flamme Gregory
Published: April 2023

Kurtosis (the fourth standardized moment of the sound pressure) has been used to assess the additional risk of hearing loss for complex or impulsive noise exposures. Murphy et al. [2012] reported the impulse peak insertion loss of five hearing protection devices (HPDs) for firearm impulse noise. Fackler et al. [2017] reported a spectral insertion loss for several HPDs assessed with firearm and shock tube impulse noise sources. Murphy [2019] previously reported the effect of five hearing protection devices on the kurtosis and insertion loss assessed with jackhammer noise. Unprotected Jackhammer noise exhibited kurtosis values between about 15 to 17, whereas protected exposures exhibited kurtosis between about 3 to 12. Anderson and Argo [2022] reported that insertion loss was unaffected by kurtosis level for seventeen HPDs measured on an acoustic test fixture under headphones. This paper will apply the complex transfer functions from Murphy et al. [2012] to the jackhammer noises measured by Murphy [2019]. The levels of the unoccluded noises transformed to the ear canal of the fixture will be compared to occluded jackhammer noises levels measured in the fixture.
Combining signal-detection theory and interaural cross-correlation approaches to account for the binaural abilities of normal-hearing listeners and listeners with “slight” hearing loss
Authors: Bernstein Leslie R.
Published: April 2023

Outstanding among the manifold contributions David M. Green made to psychophysics in general and psychoacoustics in particular was his explication and application of Signal Detection Theory (SDT). Several experimental contexts will be discussed in which a SDT approach to modeling has yielded successful and intuitively appealing accounts of measures of binaural processing. The focus will be, primarily, on relatively recently published empirical data and quantitative modeling from our laboratory. Those reports demonstrate that data obtained in binaural detection experiments conducted across the last five decades can be accounted for by combining a signal-detection-based decision variable with a cross-correlation-based model of binaural processing. Key to the development of the unified account of those experimental results was (1) the inclusion of “internal noise” within stages of the model; and (2) the calculation and inclusion of the variability of the interaural correlations of the outputs of the model for both masker-alone and signal-plus-masker conditions. It will be shown how the SDT-inspired approach has also proven useful in determining and explaining why some listeners with slight, but clinically negligible, elevations in audiometric thresholds exhibit reliable and meaningful deficits in both binaural detection and binaural discrimination tasks. [Work supported by Office of Naval Research (N00014-15-1-2140; N00014-18-1-2473)]
Chirality-selective transmission of acoustic orbital angular momentum through lossy metasurfaces
Authors: Ji Jun , Li Junfei , Gerard Nikhil JRK , Peng Xiuyuan , Cummer Steven , Jing Yun
Published: April 2023

Wave fields with acoustic orbital angular momentum have drawn greatattention because of its wide range of applications such as acoustic communication and particle manipulation. We designed, fabricated, and experimentally validated a type of lossy metasurface which enables an extremely selective transmission of acoustic wave filed depending on the chirality of its orbital angular momentum. The metasurface is composed of a phase gradient metagrating (PGM) and microperforated panel (MPP). By harnessing the multiple internal reflection of PGM and the carefully engineered loss of MPP, the left-handed incident vortex has a near-zero power transmission while its right-handed counterpart has a 60% power transmission. Such an extremely selective transmission was experimentally validated by retrieving the full scattering matrix using a generalized twelve-microphone method, which shows a good agreement with numerical simulations.
Adaptative and non-adaptive phonetic variation: Clear speech and second-language speech
Authors: Bradlow Ann
Published: April 2023

Two independent lines of research have revealed a somewhat surprising convergence between clear speech and second-language (L2) speech. Specifically, relative to conversational L1 speech, both clear speech and L2 speech typically exhibit slower speaking rates (fewer syllables per second), longer and more frequent inter-word pauses, and less segment- and syllable-level reduction. These phonetic features result in a general pattern of lower information density (more phonetic material produced for a given linguistic message or text) compounded by longer utterance durations to yield substantially lower information transmission rates for both clear speech and L2 speech relative to conversational L1 speech. However, clear speech and L2 speech diverge in terms of intelligibility. While clear speech is a highly effective strategy for enhancing overall intelligibility, L2 speech is typically characterized by greater likelihood of listener errors in word recognition accuracy. This pattern of convergent phonetics and divergent intelligibility highlights the complicated relationship between phonetic form and communicative efficiency. While clear speech is a listener-oriented talker adaptation to listener limitations, L2 speech reflects talker-oriented talker-listener misalignment. The phonetic similarities between these adaptative (clear speech) and non-adaptive (L2 speech) sources of variation underscore the dynamics of human speech communication with the talker-listener relation as the fulcrum.
Clear speech in the new digital era: Speaking and listening clearly to voice-AI systems
Authors: Zellou Georgia , Cohn Michelle
Published: April 2023

It’s a new digital era: many people regularly talk to voice-activated artificially intelligent (AI) personal assistants, such as Siri, Alexa, and Google Assistant, that spontaneously and more naturalistically produce interactive speech. Human speech patterns toward these new voice-AI interlocutors can serve as a “Turing” test for discovering how people adapt their production and perception to improve communication during spoken language interactions. In this research program, we explore how interactions with voice-AI can influence human speech patterns during short-term interactions, and the potential that this has to lead to sound change within speech communities. In this talk I will present two case studies representing the types of studies we are conducting to explore how voice-AI interactions influence human speech patterns. First, we investigate how speakers adapt their speech when talking to devices, particularly to be better understood where the devices display comprehension difficulties. Second, we examine the intelligibility of text-to-speech (TTS) and how listeners can adapt their listening strategies during interactions with devices to better understand. Our work demonstrates that examining people’s speech behavior when interacting with voice-AI can serve as a test to our scientific understanding of speech communication, language use, and even linguistic change.
Selective preconditioning of an active sound control system with virtual sensing
Authors: Elliott Stephen J. , Vered Yoav
Published: April 2023

The convergence speed of multichannel adaptive active noise control algorithms can be improved if the reference signals are preconditioned, so it is advantageous to whiten them and reduce their cross-correlations. However, this preconditioning depends on the properties of the reference signals, which will generally change over time. It may still be possible to approximate the properties of the measured reference signals using a limited number of exemplar cases. By classifying the measured reference signals into the closest of these cases, the most appropriate preconditioning can be selected for the adaptive algorithm at any one particular time. Also, one method of implementing virtual sensors is to use the additional filter method, which provides targets for the measured error signals to follow, generated from the reference signals. The performance of this virtual sensing is known to be degraded if the properties of the reference signals change, so this classification method could also be used to select the most appropriate additional filter.
Universal global compact representation of head-related transfer functions with hemi-spherical harmonics and conformal mapping
Authors: Wang Yuxiang , Bocko Mark
Published: April 2023

The head-related transfer function(HRTF) is an essential part of spatial auditory display systems. In recent years, numerous HRTF databases are established to include human subjects' measurements, which enabled data-driven research projects such as HRTF prediction and personalization. However, in most cases, each HRTF database has its own unique measuring standard and source direction grid set. It's difficult to merge and efficiently represent the global HRTF information across multiple HRTF databases. Current presentation methods, such as principle component analysis (PCA) and spherical harmonics transform (SHT), are constrained by the source grid layout and regularization errors, which lays burdens for common feature extraction from different sets of HRTF measurements. In this work, we propose a novel approach for the global compact representation of HRTFs across different measuring standards, using hemispherical harmonics (HSH) and conformal mapping. The method takes into account the spatial domain covered by the typical HRTF measurements and proves to be less contained by the source direction grids. Both numerical and auditory model experiments are performed, to examine the representation error and consistency when including multiple HRTF databases with different measuring standards and grid layouts. In continuing work, we are using this method as a pre-processing approach for HRTF personalization utilizing multiple HRTF databases.
Binaural externalization processing method for object-based audio rendering
Authors: Landschoot Christopher R. , Jot Jean-Marc
Published: April 2023

In both entertainment and professional applications, conventionally produced stereo or multi-channel audio content is frequently delivered over headphones or earbuds. Use cases involving object-based binaural audio rendering include recently developed immersive multi-channel audio distribution formats, along with the accelerating deployment of virtual or augmented reality applications and head-mounted displays. The appreciation of these listening experiences by end users may be compromised by an unnatural perception of the localization of frontal audio objects: commonly heard near or inside the listener’s head even when their specified position is distant. This artifact may persist despite the provision of perceptual cues that have been known to partially mitigate it, including artificial acoustic reflections or reverberation, head-tracking, individualized HRTF processing, or reinforcing visual information. In this paper, we review previously reported methods for binaural audio externalization processing, and generalize a recently proposed approach to address object-based audio rendering.
Target ranging by echolocation in bats: Performance and mechanisms
Authors: Moss Cynthia F. , Kothari Ninad B. , Wohlgemuth Melville , Luo Jinhong , Krishna Aditya , Yin Xiaoyan
Published: April 2023

James Simmons’s early research on sonar ranging in echolocating bats generated two groundbreaking discoveries: (1) Bats compute object distance from the time delay between sonar calls and echoes, and they discriminate echo-delay differences in the microsecond range [Simmons, https://psycnet.apa.org/doi/10.1121/1.1913559 (1973)] and (2) A population of auditory neurons show facilitated and echo delay-tuned responses, a posited neural substrate of sonar ranging [Feng et al., https://10.1126/science.705350 (1978)]. These findings spawned decades of biosonar research around the world, and this talk will summarize three new findings on the mechanisms of sonar ranging in the big brown bat, Eptesicus fuscus. (1) Echo-delay tuned neurons in the midbrain of the free-flying bat show 3D spatial tuning to echoes from physical objects, and sonar-guided attention evokes sharper delay-dependent response areas and shifts to shorter echo delays. (2) Local field potential recordings from auditory midbrain neurons in the passively listening bat encode the time interval between call-echo pairs in the microsecond range, with accuracy dependent on signal duration and bandwidth. (3) A population of hippocampal CA1 neurons encodes the distance of sonar objects in bats as they track moving targets, and responses of hippocampal neurons depend on the production of sonar calls that yield echo returns.