bluuebunny/crossref_metadata_2025 huggingface dataset:
Higher energy state approximations in the “Many interacting worlds” model
Authors: Loomis Alex , Sethuraman Sunder
Published: May 2024

In the “Many Interacting Worlds” (MIW) discrete Hamiltonian system approximation of Schrödinger’s wave equation, introduced in Ref. 11, convergence of ground states to the Normal ground state of the quantum harmonic oscillator, via Stein’s method, in Wasserstein-[Formula: see text] distance with rate [Formula: see text] has been shown Refs. 5, 13, and 15. In this context, we construct approximate higher energy states of the MIW system, and show their convergence with the same rate in Wasserstein-1 distance to higher energy states of the quantum harmonic oscillator. In terms of techniques, we apply the “differential equation” approach to Stein’s method, which allows to handle behavior near zeros of the higher energy states.
Dynamic Analysis of Functionally Graded Sandwich Doubly Curved Nanoshells Using Variable Nonlocal Elasticity Theory
Authors: Dadashi Mahdi , Mahdiabadi Morteza Karamooz
Published: May 2024

Sandwich nanoshells consisting of functionally graded materials (FGMs) offer promise in aerospace, energy and biomedical applications due to their tunable properties. However, a comprehensive understanding of the vibration behavior of such shells is lacking. This work develops an efficient analytical model to study free vibration of sandwich nanoshells with three FGM configurations: FGM face-sheets and metal core (Type A), FGM face-sheets and ceramic core (Type B), and FGM core and face-sheets (Type C). A doubly curved shell geometry representing spherical, hyperbolic–parabolic and cylindrical shells in addition to flat plates is considered. Effective material properties of nanolaminates are computed using a volume fraction-based model. First-order shear deformation theory and modified nonlocal elasticity theory with variable nonlocal parameters are employed to derive the governing equations. Hamilton’s principle is used to obtain the equations of motion. Navier’s solution technique analytically solves the equations for simply supported boundary conditions. Accuracy is validated through comparisons with literature results. Parametric studies analyze the influence of thickness ratio, material gradation, nonlocal parameter, and shell type on frequencies. Results show that Type A configuration yields the highest frequencies. Dimensionless frequency decreases with increasing nonlocal parameter and side-to-thickness ratio. The model provides design insights into vibration behavior of such nanosandwich structures with potential applications in nanodevices and energy harvesting.
Multi-Response Bridge Regularization Parameter Selection via Multivariate Generalized Information Criterion
Authors: Ghatari Amir Hossein , Aminghafari Mina
Published: May 2024

This paper proposes a multivariate form of generalized information criterion (MGIC) for the multivariate response bridge regression (multi-bridge) model. Also, we prove the identifiability of the multi-bridge as a prerequisite for model selection. We introduce the general form of MGIC for regularization parameter selection in the multi-bridge model. We assess the performance of MGIC variants from three viewpoints: consistency of the obtained models, analysis of high-dimensional data, and comparison to other criteria. Based on the numerical study, we reach better performance for MGIC in comparison to other common criteria (cross-validation and GCV) using simulated and real datasets.
Relative Frobenius formula
Authors: Aizenbud Avraham , Avni Nir , Krauz Yoav
Published: May 2024

For a finite group [Formula: see text], Frobenius found a formula for the values of the function [Formula: see text] for even integers [Formula: see text], where [Formula: see text] is the set of irreducible representations of [Formula: see text]. We generalize this formula to the relative case: for a subgroup [Formula: see text], we find a formula for the values of the function [Formula: see text]. We apply our results to compute the E-polynomials of Fock–Goncharov spaces and to relate the Gelfand property to the geometry of generalized Fock–Goncharov spaces.
Sample complexity bounds for the local convergence of least squares approximation
Authors: Trunschke Philipp
Published: May 2024

We consider the problem of approximating a function in a general nonlinear subset of [Formula: see text], when only a weighted Monte Carlo estimate of the [Formula: see text]-norm is accessible. The concept of sample complexity, i.e. the number of sample points necessary to achieve a prescribed error with high probability, is of particular interest in this setting. Reasonable worst-case bounds for this quantity exist only for particular model classes, like linear spaces or sets of sparse vectors. However, the existing bounds are very pessimistic for more general sets, like tensor networks or neural networks. Restricting the model class to a neighborhood of the best approximation allows us to derive improved worst-case bounds for the sample complexity. When the considered neighborhood is a manifold with positive local reach, its sample complexity can be estimated through the sample complexities of the tangent and normal spaces and the manifold’s curvature.
TIHN: Tensor Improved Huber Norm for low-rank tensor recovery
Authors: Liu Youheng , Wang Yulong , Chen Longlong , Wang Libin , Hu Yutao
Published: May 2024

Tensor Robust Principal Component Analysis (TRPCA) has received much attention in many real-world applications which aims to recover a low-rank tensor corrupted by sparse noise. Most existing TRPCA methods usually regularize the low-rank component by minimizing its Tensor Nuclear Norm (TNN). However, the original TNN shrinks all of the singular values with the same penalty which generally leads to suboptimal results. The reason is that the large singular values should be less penalized since they usually correspond to salient information of the real-world tensor. In this work, we develop a Tensor Improved Huber Norm (TIHN) which considers the difference between the singular values of tensor. The TIHN can achieve better performance by recovering the large and significant singular values exactly. We also establish the Huber TRPCA (HTRPCA) method by utilizing the proposed TIHN. In addition, an efficient optimization algorithm based on the half-quadratic theory and Alternating Direction Method of Multipliers (ADMM) framework is designed to implement the HTRPCA. Finally, experiments on color image recovery and video recovery validate the effectiveness of the proposed method.
Projection hypothesis in the setting for the quantum Jarzynski equality
Authors: Konishi Eiji
Published: May 2024

Projective quantum measurement is a theoretically accepted process in modern quantum mechanics. However, its projection hypothesis is widely regarded as an experimentally established empirical law. In this paper, we combine a previous result regarding the realization of a Hamiltonian process of the projection hypothesis in projective quantum measurement, where the complete set of the orbital observables of the center of mass of a macroscopic quantum mechanical system is restricted to a set of mutually commuting classical observables, and a previous result regarding the work required for an event reading (i.e. the informatical process in projective quantum measurement). Then, a quantum thermodynamic scheme is proposed for experimentally testing these two mutually independent theoretical results of projective quantum measurement simultaneously.
Traversable wormholes in 4D EGB gravity
Authors: Godani Nisha
Published: May 2024

In this work, the spherically symmetric wormhole solutions have been obtained in the four-dimensional Einstein–Gauss–Bonnet (4D EGB) gravity with isotropic and anisotropic matter sources. With each type of source, the traversable wormholes satisfying asymptotic flatness and flare-out conditions are developed. Further, the energy conditions explaining the nature of the matter in the interior of the wormhole are tested and the stability of wormhole solutions has been analyzed.
On a fully coupled nonlocal multipoint boundary value problem for a dual hybrid system of nonlinear q-fractional differential equations
Authors: Alsaedi Ahmed , Bohner Martin , Ahmad Bashir , Alharbi Boshra
Published: May 2024

A new class of nonlocal multipoint boundary value problems involving a dual hybrid system of nonlinear Riemann–Liouville-type [Formula: see text]-fractional differential equations is studied in this paper. Existence and uniqueness results for the given problem are derived by applying the Leray–Schauder nonlinear alternative and the Banach contraction mapping principle. Examples are presented for illustrating the obtained results. The work established in this paper is a useful contribution to the existing literature on [Formula: see text]-fractional differential equations. Some interesting special cases are also discussed.
Influence of dispersal on the dynamics of an eco-epidemiological two-patch predator–prey model in deterministic and stochastic environment with ratio-dependent functional responses
Authors: Dutta Protyusha , Sahoo Debgopal , Samanta Guruprasad
Published: May 2024

An eco-epidemiological predator–prey system containing two separate prey patches has been assessed in this paper with disease in prey population involving ratio-dependent functional responses and incidence rates. The model dynamics is studied by employing environmental perturbations to develop more genuine as well as realistic dynamics. This comprehensive study offers analytical insights into the positivity and uniform boundedness of the model system. Through numerical investigations, the study reveals the occurrence of local bifurcations, bistable regions, hysteresis phenomena, and parametric regions where saddle-node and transcritical bifurcation curves exist. Utilizing appropriate Lyapunov functions, it is demonstrated that a unique globally positive solution emerges from positive initial values. It has also been proved that the suggested model is stochastically ultimate bounded. Afterward, certain sufficient criteria illustrate the extermination of disease and persistence in mean. Notably, stochastic perturbations are shown to potentially impede disease propagation, suggesting strategies for dynamically controlling the spread of the illness. Additionally, the study derives a set of requirements for the existence of an ergodic stationary distribution. Numerous numerical simulations, conducted using MATLAB and MATCONT, effectively illustrate the theoretical findings.
Surfaces with a common asymptotic curve in the 3D Galilean space 𝔾3
Authors: Nazra Sahar H. , Abdel-Baky Rashad A.
Published: May 2024

In this study, we consider the problem of how to characterize a surface family from a given common asymptotic curve in a three-dimensional Galilean space [Formula: see text]. We obtain a parametrization of the surface such that the surface tangent plane is coincident with the curve osculating plane. The extension to ruled surfaces is also outlined. We illustrate this method by presenting some examples.
Modeling and analysis of a novel 6-DOF magnetic levitation system with experimental verification
Authors: Cao Shinan , Niu Pingjuan , Sheng Sha , Wang Bin , Liu Qiang , Han Bangchen
Published: May 2024

To improve the uniformity of magnetic flux and increase the stroke of the magnetic levitation system, this paper designs a novel 6-DOF magnetic levitation system and proposes an improved novel Halbach array. First, a repulsive passive magnetic bearing is utilized to provide levitation force, leading to a noticeable reduction in levitation power consumption. Then, a magnetic circuit model for the magnetic levitation system is established, and the improved novel Halbach array is optimized based on this model. Next, the stable levitation model and measurement model for the system are established, and the magnetic field distribution and magnetic bearing stiffness are analyzed. Results indicated an increase of 0.1[Formula: see text]T in the maximum magnetic flux density, accompanied by an improvement in the uniformity of magnetic flux. Additionally, there is an enhancement of 10% in magnetic bearing stiffness. Finally, a prototype of the system is constructed, and the stable levitation simulation and experiment of the actuator are conducted with this system. The maximum levitation absolute displacement error obtained by simulation is about 655[Formula: see text]nm, and the experimental results exhibited a maximum levitation absolute displacement error of approximately 750 nm for the system, confirming the effectiveness of the proposed modeling method.
Robotic Assistance and Haptic Feedback in Arthroscopic Procedures: Design and Preliminary Evaluation of a Two-Arm System
Authors: Li Teng , Badre Armin , Tavakoli Mahdi
Published: May 2024

Robot-assisted arthroscopic surgery has been receiving growing attention in the field of orthopedic surgery. Most of the existing robot-assisted surgical systems in orthopedics place more focus on open surgery than minimally invasive surgery (MIS). In traditional arthroscopic surgery, the surgeon needs to hold an arthroscope with one hand while performing the surgical operations with the other hand, which can restrict the dexterity of the surgical performance and increase the cognitive load. On the other hand, the surgeon heavily relies on the arthroscope view when conducting the surgery, whereas the arthroscope view is a largely localized view and lacks depth information. To assist the surgeon in both scenarios, in this work, we develop a two-arm robotic system. The left-arm robot is used as a robot-assisted arthroscope holder, and it can hold the arthroscope still at a designated pose and reject all other potential disturbances, while also allowing the operator to move it via a pedal switch whenever needed. The left-arm robot is implemented with an impedance controller and a gravity iterative learning (Git) scheme, where the former can provide compliant robot behavior, thus ensuring a safe human–robot interaction, while the latter can accurately learn for gravity compensation. The right-arm robot is used as a robot-assisted surgical tool, providing virtual fixture (VF) assistance and haptic feedback during the surgery. The right-arm robot is implemented with a point-based VF algorithm, which can generate VF directly from point clouds in any shape, render force feedback, and deliver it to the operator. Furthermore, the VF, the bone, and the surgical tool position are visualized in a 3D digital environment as additional visual feedback for the operator. A series of experiments are conducted to evaluate the effectiveness of the prototype. The results demonstrate that both arms can provide satisfactory assistance as designed.
The Digital Pound: A Plan Designed to Fail?
Authors: Milne Alistair
Published: May 2024

The UK authorities have consulted on the issue of the ‘digital pound’, a retail central bank digital currency (CBDC) for general use in payments by UK households and firms. The stated ambition is a new form of central bank money, used alongside Bank of England notes and commercial bank deposits. There are inherent contradictions in these plans. Promoting adoption requires that users should be able to freely and conveniently receive and send digital pound payments and that account services can compete effectively with commercial bank transaction accounts. Containing the risks of retail CBDC to financial stability requires doing the opposite: limiting the use of the digital pound and handicapping account providers in their competition with commercial banks. To resolve this contradiction, ambition should be scaled back, focusing on specific and narrow use cases that cannot be easily addressed using commercial bank transaction accounts.
Deep Domain Adaptation: A Sim2Real Neural Approach for Improving Eye-Tracking Systems
Authors: Nguyen Viet Dung , Bailey Reynold , Diaz Gabriel J. , Ma Chengyi , Fix Alexander , Ororbia Alexander
Published: May 2024

Eye image segmentation is a critical step in eye tracking that has great influence over the final gaze estimate. Segmentation models trained using supervised machine learning can excel at this task, their effectiveness is determined by the degree of overlap between the narrow distributions of image properties defined by the target dataset and highly specific training datasets, of which there are few. Attempts to broaden the distribution of existing eye image datasets through the inclusion of synthetic eye images have found that a model trained on synthetic images will often fail to generalize back to real-world eye images. In remedy, we use dimensionality-reduction techniques to measure the overlap between the target eye images and synthetic training data, and to prune the training dataset in a manner that maximizes distribution overlap. We demonstrate that our methods result in robust, improved performance when tackling the discrepancy between simulation and real-world data samples.
Using Deep Learning to Increase Eye-Tracking Robustness, Accuracy, and Precision in Virtual Reality
Authors: Barkevich Kevin , Bailey Reynold , Diaz Gabriel J.
Published: May 2024

Algorithms for the estimation of gaze direction from mobile and video-based eye trackers typically involve tracking a feature of the eye that moves through the eye camera image in a way that covaries with the shifting gaze direction, such as the center or boundaries of the pupil. Tracking these features using traditional computer vision techniques can be difficult due to partial occlusion and environmental reflections. Although recent efforts to use machine learning (ML) for pupil tracking have demonstrated superior results when evaluated using standard measures of segmentation performance, little is known of how these networks may affect the quality of the final gaze estimate. This work provides an objective assessment of the impact of several contemporary ML-based methods for eye feature tracking when the subsequent gaze estimate is produced using either feature-based or model-based methods. Metrics include the accuracy and precision of the gaze estimate, as well as drop-out rate.
Communication Complexity of the Secret Key Agreement in Algorithmic Information Theory
Authors: Gürpιnar Emirhan , Romashchenko Andrei
Published: May 2024

It is known that the mutual information, in the sense of Kolmogorov complexity, of any pair of strings
x
and
y
is equal to the length of the longest shared secret key that two parties can establish via a probabilistic protocol with interaction on a public channel, assuming that the parties hold as their inputs
x
and
y
, respectively. We determine the worst-case communication complexity of this problem for the setting where the parties can use private sources of random bits.

We show that for some
x
,
y
the communication complexity of the secret key agreement does not decrease even if the parties have to agree on a secret key, the size of which is much smaller than the mutual information between
x
and
y
. However, we discuss a natural class of
x
,
y
such that the communication complexity of the protocol declines gradually with the size of the derived secret key.

The proof of the main result uses the spectral properties of appropriate graphs and the expander mixing lemma, as well as information-theoretic techniques, including constraint information inequalities and Muchnik’s conditional descriptions.

A preliminary version of this article was published in the proceedings of MFCS 2020. In the present version, we give full proofs of all theorems and get rid of the assumption that the number of random bits used in the communication protocols is polynomial.
High-Frequency Electrochemical Impedance Spectroscopy for Detecting Li Deposition Toward Assessing Thermal Stability in LiBs
Authors: Ishikawa Keisuke , Komagata Shogo , Morimoto Ryohei , Ishigaki Masanori , Kondo Hiroki , Sasaki Tsuyoshi
Published: May 2024

Li deposition decreases the thermal stability of Li-ion batteries (LiBs), reducing safety. We have developed High-Frequency Electrochemical Impedance Spectroscopy (HF-EIS) to detect Li deposition from the high-frequency real part impedance in the MHz range. The evaluation of the relationship between the onset temperature of thermal runaway and the change in high-frequency impedance demonstrated that HF-EIS is capable of quantitatively evaluating the safety associated with Li deposition. The HF-EIS can be a diagnostic tool for safety quantification and can contribute to the development of battery materials by reducing the cost of destructive testing.
(Invited) CdS/Ti-Si-O Composite Photoanode for Photoelectrochemical Hydrogen Generation
Authors: Feng Weilong , Ding Dongyan , Chen Zhi
Published: May 2024

Advancements in clean energy drive socio-economic development and foster a sustainable future by restructuring energy systems and promoting low-carbon development. In this paper, we presented a comprehensive investigation on the design and performance characterization of CdS/Ti-Si-O composite photoanodes for photoelectrochemical (PEC) hydrogen generation. Silicon-doped TiO2 nanotube arrays were fabricated through anodization of Ti-5Si alloy, followed by the deposition of CdS using the SILAR (successive ionic layer adsorption and reaction) process, resulting in nanostructured Ti-Si-O photoanodes modified with CdS. The composite photoanodes were characterized in terms of their composition, microstructure, optical properties and photoelectrochemical hydrogen production performance. The composite photoanodes revealed a notable enhancement in PEC hydrogen generation properties with a photocurrent density of 7.86 mA/cm2，which was 19.15 times and 9.59 times to those of the undoped TiO2 photoanode and Ti-Si-O photoanode, respectively. The Si-doping mechanism of the photoanodes was elucidated through Density Functional Theory (DFT) calculations. The synergistic combination of Si-doping and CdS modification represents a novel and promising approach for the design of efficient nanostructured photoanodes.
A New Integration Scheme to Prevent Chemical Attack on Floating Polysilicon Gate of Non-Volatile Memory
Authors: Yang Yuming , Kong KIM Foong , Teh Young Way , Zhou Guanyu , Yu Nianhong , Yu Kankan
Published: May 2024

Abstract—Silicon pitting has been observed on floating gate polysilicon layer of embedded non-volatile memory(e-NVM) process due to chemical attack caused by HBr residual interacting with moisture. This paper successfully demonstrates a new integration scheme for a robust floating gate process against silicon attack for embedded stacked/split gate non-volatile memory process. Firstly, CF4 was introduced into floating gate polysilicon etch recipe to replace HBr, which has been CMOS gate polysilicon etch gas in traditional logic process due to the advantage of higher selectivity despite the disadvantage of low vaporability, for better or cleaner process control. Secondly, an additional plasma removal stripping (PRS) clean step was added before chemical removal stripping (CRS) to give better etch by-product cleaning, even though there is no photoresist and lithography involved on the poly blanket etch for the better etch by-product cleaning. This new scheme has been verified using inline optical inspection defect-scan to prove the sufficient process margin for better mass production control that came from improved manufacturing Queue-time margin (longer waiting time) between dry-etch step, CRS step, and subsequent downstream process steps.
(Invited) Preparation of N-Type and P-Type Doped Single Crystal Diamonds with Laser-Induced Doping and Microwave Plasma Chemical Vapor Deposition
Authors: Guo Linhai , Tian Li , Wang Hui , Meng Lingxue , Feng Chujun
Published: May 2024

In this study, n-type doped single-crystal diamonds were successfully prepared under normal temperature and pressure conditions using laser-induced doping. 248nm pulsed laser beams with nanosecond duration were irradiated on the single crystal diamond substrate immersing in an 85% phosphoric acid solution and it introduced phosphorus doping to form an n-type doped thin layer. The resistivity of the doped region significantly decreased compared to that of the single-crystal diamond. After depositing a titanium electrode, the resistivity of the doped film obtained by Van der Pauw Technique was determined to be 1.5×10-4 Ω·cm. Furthermore, p-type doped single-crystal diamonds were successfully prepared by introducing boron during the growth process using Microwave Plasma Chemical Vapor Deposition（MPCVD）. It was demonstrated that the proposed technique can introduce impurities into single crystal diamonds to form doped conductive thin layers.
Gallium Nitride Electrodeposition at Indium Tin Oxide and Fluorine Tin Oxide Electrodes in Ammonium Nitrate and Gallium Nitrate Aqueous Solution
Authors: Leyva Aranzabal Mauricio A. , Cabrera Carlos R.
Published: May 2024

Gallium nitride thin films in semiconductor technology have garnered interest. This study aims to develop an effective GaN electrodeposition technique applicable where needed. To determine the optimal conditions, cyclic voltammetry (CV) was done on a boron-doped diamond electrode at 0.01 mV/s potential scan rate and at 0.8 V vs. Ag/AgCl (Saturated KCl) constant applied potential. In the CV study, a well-defined peak formed at -1.75 V vs. Ag/Ag/Cl (Saturated KCl). To start examining thin film features on Indium Tin Oxide (ITO) and Fluorine Tin Oxide (FTO) electrodes, chronoamperometry (CA) measurements were done at time scales ranging from 3600s to 14,000s and at a constant applied potential of -1.7 V vs. Ag/AgCl (Saturated KCl). The characterization methods used to examine the samples included SEM and EDS. The optimal weight electrodeposition percentages of Ga and N on ITO were 10.3% and 27.2% and 47.3% and 12.7% on FTO respectively.
(Invited) III-Nitride Ultraviolet LEDs and Lasers for Applications in Biology and Medicine
Authors: Zhang Jing , Melanson Bryan , Seitz Matthew , Boisvere Jacob
Published: May 2024

Solid-state ultraviolet (UV) light emitters are being developed for emerging biomedical applications such as surface sterilization, air/water purification, and medical treatments as a replacement for mercury vapor lamps. While these UV emitters offer many advantages over mercury lamps, such as more compact form factors, tunable emission wavelengths, and greatly increased lifetimes, they also suffer from a number of issues which hinder their implementation in many potential applications. UV emitters are based on AlGaN heterostructures which usually have very poor external quantum efficiencies (EQEs) of less than 10%, with EQEs decreasing with emission wavelength. This makes it very challenging to realize high efficiency UV emitters whose high energy photons are capable of inactivating viruses, bacteria, and other pathogens. This work discusses recent developments made by the Zhang Research Group at the Rochester Institute of Technology in improving the efficiencies of UV LEDs and lasers.
Selectivity Study of Anodic Seawater Electrolysis Catalysts Using the Rotating Ring-Disc Electrode Method
Authors: Horner Oliver , Gyenge Elod Lajos , Wilkinson David P.
Published: May 2024

Seawater Electrolysis is an exciting alternative to freshwater electrolysis; however, it suffers from a multitude of issues that must be resolved before the technology can be scaled. Corrosive hypochlorite forms at the anode of seawater electrolysis and can damage catalysts and electrolyzer components. Hypochlorite is unstable and can decay, particularly when exposed to heat and metal ions, which can lead to erroneously high oxygen evolution reaction (OER) selectivity conclusions, resulting in poor catalyst and electrolyzer component selection. In this study, we use the rotating ring-disc electrode technique to characterize the selectivity of IrO2, NiO, Co3O4, RuO2, Pt and PtRu electrocatalysts in situ at near-neutral pH (8.4) with linear scan voltammetry (LSV), potentiostatic and galvanostatic experiments. Our findings reveal that elevated temperatures are conducive to higher OER selectivity. Furthermore, when we increased the chloride concentration in the electrolyte with an IrO2 catalyst, we observed that although the overall selectivity towards the OER reaction decreased, the OER current independently increased, indicating a synergistic relationship.
Influence of Oxygen Vacancies in La0.4Sr0.6FeO3-δ
Perovskite Oxide Nanoparticles for the Oxygen Evolution Reaction
Authors: Qing Geletu , Chen Jingyi
Published: May 2024

Oxygen vacancies are important factors to tune the performance of oxide catalysts for the oxygen evolution reaction (OER). However, it remains challenging how to control the concentration of the oxygen vacancies and decouple their effects on OER from other factors. In this work, we use a specific composition/phase La0.4Sr0.6FeO3-

d
perovskite oxide as an example to tailor the oxygen vacancies of their nanoparticulate using a modified molten salt synthesis and ozone treatment. The OER performance of the resulting La0.4Sr0.6FeO3-

d
nanoparticles with different degree of oxygen vacancies ranging from 0 to 25% are compared. The OER reactivity increases with increased oxygen vacancies in the materials, but the change is nonlinear. The OER stability, on the other hand, has a bimodal distribution. The activities of fully oxidized sample and the most oxygen-deficient sample degrade slower than the two samples in the middle. The results suggest that it is feasible to design catalysts with oxygen vacancy to be the most OER active and stable. Further investigation into the oxygen vacancy – active site relation would offer guiding principle to design and synthesize high OER performance oxide catalysts.
In-situ X-ray Fluorescence Analysis of In-plane Cerium-ion Distribution Under Humidity Gradients in Proton Exchange Membrane
Authors: Morita Kaoruko , Takezawa Aika , Kitano Naoki , Kuwaki Akira , Kato Akihiko , Yamaguchi Satoshi , Shinozaki Kazuma , Orikasa Yuki
Published: May 2024

Cerium ions are incorporated into proton exchange membranes (PEMs) of fuel cells to mitigate its chemical degradation caused by radical species. However, under fuel cell operating conditions, cerium ions move in in-plane direction in the cell by humidity gradient. This cerium ion transport results in cerium ion depletion leading to accelerated chemical degradation. This study developed an in-situ and operando measurement technique utilizing synchrotron high-energy X-ray fluorescence spectroscopy to monitor the cerium ion transport across the membrane under the in-plane humidity gradient. This method effectively tracks the dynamic behavior of cerium ions under fuel cell operating conditions.
Micropatterning MXene/TiO2 Nanocomposite Ink for Gas Sensing
Authors: Liu Jinhong , Chen Chen , 夏 胜辉 , Leatt Kyle , Khosla Ajit , Thundat Thomas
Published: May 2024

This work describes the preparation, characterization, and micropatterning of MXene(Ti3C2)/TiO2 nanocomposite inks. MXene nanopowder was oxidized to form MXene/TiO2 nanocomposite powder using an air-aging method. The MXene/TiO2 inks were prepared using deionized water (H2O) as the solvent/dispersant and polyvinylpyrrolidone (PVP) as the surfactant. Various techniques were utilized to characterize the MXene/TiO2 nanocomposite material, and the BET results showed the preferential adsorption of butane of the MXene/TiO2 coating. Utilizing an ultrasonic dispersion printer in conjunction with a stencil mask, the MXene/TiO2 nanocomposite ink was successfully printed onto a 10mm*10mm gold-plated silicon substrate. This process achieved millimeter-level precision control, enabling the printing of fine lines with a width of 1μm and a spacing of 0.05mm. Furthermore, this technique demonstrated the ability to render various complex patterns, thus exemplifying the potential of MXene/TiO2 nanocomposite ink in the field of micro- and nano-manufacturing.
Micropatternable Ink Composed of MAX Phase ZIF-8 for Gas Sensing Applications
Authors: Chen Chen , 夏 胜辉 , Liu Jinhong , Leatt Kyle , Thundat Thomas , Khosla Ajit
Published: May 2024

This work provides a detailed introduction to the preparation methods, structural characteristics, and various performance tests of the Ti3C2/ZIF-8 composite material. Initially, the composite material is obtained through the synthesis, mixing, and subsequent processing of MXene solution and ZIF-8 nanoparticles. The coating structure and properties were comprehensively characterized using SEM, TEM, and XRD. These analyses revealed the material's layered structure, high crystallinity, and surface activity. BET analysis of Ti3C2/ZIF-8 also shows excellent gas adsorption-desorption performance, having an especially high-efficiency adsorption capacity for VOCs. TGA further demonstrates the thermal stability and chemical stability of Ti3C2/ZIF-8 and its printability was tested indicating widespread application potential in coating preparation through ultrasonic spray technology. Finally, we show methods to regulate and control coating thickness and roughness for precision manufacturing. These analyses together emphasize the application value of Ti3C2/ZIF-8 in fields such as gas-storage, gas-separation, and environmental monitoring.
Design and Characterization of Printed Flexible Humidity Sensor
Authors: Banothu Akhil Naik , Budhraja Vinay , Sundaravadivel Prabha , Fletcher Reginald , Reddy Krishna
Published: May 2024

The development of humidity sensors is essential for applications in the environmental, agriculture, medical and semiconductor industries. This research focused on using advanced printed board circuit (PCB) printing technology to fabricate a humidity moisture sensor. The fabrication of humidity sensor was done using two different polymers: p-HEMA and polyimide, and the performance was compared. Humidity sensors with p-HEMA showed higher capacitance value and more sensitivity than the humidity sensors with polyimide. The variation in sensitivity was higher between the relative humidity from 60% to 90% than between 45% to 60%.
Advancements in Glucose Monitoring: A Thin Film ZnO-Nanoflakes Based Highly Sensitive Wearable Biosensor for Noninvasive Sweat-Based Point-of-Care Monitoring for Diabetes
Authors: Hossain G M Mehedi , Jalal Ahmed Hasnain , Pala Nezih , Alam Fahmida
Published: May 2024

In the contemporary global landscape, diabetes is a concerning presence that contributes to noteworthy mortality rates. The etiology of this condition involves a subtle interaction between insulin deficiency and elevated blood sugar levels. Against this backdrop, the necessity for prompt, accurate, and continuous noninvasive monitoring of glucose concentrations becomes notably evident. The electrochemical flexible glucose biosensor was fabricated by immobilizing glucose oxidase (GOx) on ZnO nanoflakes, possessing a 20nm thickness, and synthesized on an Au-coated stretchable PET film. The sensitivity of the flexible biosensor was determined by 29.97μA/decade/cm², and the minimum detection limit was 1μM. The coefficient of determination was 97.76%, which is significantly linear.
(Invited) Ferroelectric Nonvolatile Capacitive Synapse for Charge Domain Compute-in-Memory
Authors: Phadke Omkar , Kim Tae-Hyeon , Luo Yuan-Chun , Yu Shimeng
Published: May 2024

The ferroelectric field effect transistor (FeFET) can be configured in nvCAP mode to enable a small-signal capacitive readout. Operating the FeFET in nvCAP mode for Charge-domain Compute-in-Memory provides benefits such as reduced power consumption and suppressed read disturb. In this review article, working of FeFET in nvCAP mode is described. Further, the TCAD study results are summarized to optimize the FeFET structure for maximizing the device performance in nvCAP mode, where the gate area and the overlap region decides the ON and OFF state capacitance. Next, the reliability aspects of nvCAP are discussed. The FeFET in nvCAP demonstrates an initial endurance of 106 P/E cycles, which can be further extended by 100× by performing a recovery operation. The nvCAP device shows a retention of at least 1 day at 850C for the fresh, fatigued and recovered state of the device, making it a suitable candidate for Compute-in-Memory.
First Report of Porcine Parvovirus 2 (PPV2) in Pigs from Colombia Associated with Porcine Reproductive Failure (PRF) and Porcine Respiratory Disease Complex (PRDC)
Authors: Vargas-Bermudez Diana S. , Mainenti Marta , Naranjo-Ortiz María F. , Mogollon José Darío , Piñeyro Pablo , Jaime Jairo
Published: May 2024

Pigs are affected by various parvoviruses (PPVs); eight have been reported to date (PPV1–PPV8). Porcine parvovirus 1 is considered a primary agent of porcine reproductive failure (PRF), while it is unknown whether other PPVs impact porcine health. Recently, the presence of PPV2 has been confirmed in the lung, either as a single agent or in the form of coinfection with other respiratory; therefore, it has been proposed as a potential participant in the porcine respiratory disease complex (PRDC). In the present study, the presence of PPV2 alone and coinfection with other viruses (PCV2, PCV3, and PRRSV) was evaluated in lung samples obtained from pigs with respiratory signs (respiratory group: RG) (n = 146) and stillborn lungs (stillborn group: SG) (n = 19) from 82 farms in the five regions with the highest swine production in Colombia. The overall PPV2 prevalence was 37.6% (62/165), with the highest proportion mainly detected in grow‐finisher pigs (62.5%), while its herd prevalence was 51.2% (42/82). The most prevalent virus was PRRSV in both groups, while PPV2 alone was found only in the RG group. The most common dual coinfection in the RG and SG was PCV2/PRRSV (17.8% and 10.5%), while the most frequent coinfections involving PPV2 in the RG were PPV2/PCV2 (7.5%) and PPV2/PRRSV (4%) and PPV2/PCV2 (5.3%) in the SG. The most common triple coinfection was PPV2/PCV2/PRRSV at 15% in the RG and 21% in the SG, while quadruple coinfection PVV2/PCV2/PCV3/PRRSV was detected only in the RG (5.5%). Histopathological evaluation of 21 PPV2‐positive lungs showed variable degrees of histiocytic or lymphohistiocytic interstitial pneumonia (9%) in the RG, while no significant changes were observed in SG; in addition, neutrophilic bronchopneumonia was observed in 73.7% if cases evaluated. In situ hybridization‐RNAScope® confirmed the presence of PPV2 within pulmonary lesions in 2/19 RG pigs, while no in situ detection was observed in the SG pigs. The phylogenetic evaluation of seven PPV2 sequences detected in Colombia was compared with another 102 reported sequences, indicating that the Colombian strains are located in clade 2. Our results confirm the presence of PPV2 in pigs with PRDC alone and pigs coinfected with PCV2, PCV3, and PRRSV. Likewise, its presence alone or in coinfection in stillbirths suggests that PPV2 is also involved in PRF.
Problematizing Dominant Assumptions about Unpaid Support through Exploring Case Study Profiles of Older Home Care Clients
Authors: Funk L. , Kuryk K. , Spring L. , Keefe J.
Published: May 2024

Despite efforts to acknowledge diversity among unpaid caregivers, Canadian research, advocacy, practice, and policy tend to be based in and to reproduce dominant social and institutional expectations and assumptions about who provides unpaid support and why, and what this support looks like. The objective of this analysis is to generate unique insights into unpaid care by exploring the situations of older adult home care clients, who had participated in a larger longitudinal, qualitative research study. In that study, qualitative case study interviews were conducted with twelve home care clients, their identified family or friend caregiver, home care aide, case coordinator, and agency supervisor (129 interviews in total). Case study profiles compiled over time generated deeper information about the availability and capacity of informal sources of support for these clients, which prompted abductive analysis in relation to dominant assumptions typically made about caregivers in research, policy, and practice. Specifically, only one case (participant) had a caregiver whose profile closely matched dominant conceptualizations. In the remaining eleven cases, we found situations wherein: (a) caregivers grappled with physical or mental health challenges limiting their participation in care (sometimes meaning the client is themselves a caregiver, or the caregiver is also receiving home care services); (b) caregivers facing burnout sought to delimit their participation in care; (c) caregivers’ participation was limited by older adults’ reluctance to accept their help; (d) caregivers were largely unavailable, unreliable, or peripheral; or (e) client’s unpaid support networks were diffuse without a clearly central or identifiable “caregiver.” Findings are used to nuance and problematize widely held assumptions about caregivers, particularly their availability and capacity. Discussion highlights the need for research, policy, and programs related to unpaid caregiving to better reflect the lived realities of this support for older adults and often overlooked sources of diversity in caregiver circumstances and roles.
An Electromechanical Impedance‐Based Imaging Algorithm for Damage Identification of Chemical Milling Stiffened Panel
Authors: Jiang Xie , Zhou Wensong , Chen Xize , Zhang Xin , Xie Jiefeng , Tang Tao , Zhang Yuxiang , Yang Zhengwei
Published: May 2024

The multiple intersecting stiffeners on the chemical milling stiffened panel (CMSP) limit the application of active health monitoring methods on it. An imaging algorithm based on electromechanical impedance (EMI) and probability‐weighting is proposed to achieve quantitative evaluation and localization of the damage on CMSP. The proposed algorithm compensates for the difference in sensor performance with coefficients and there is no need to determine the key parameters of the algorithm through prior experiments. In the paper, the applicability of ultrasonic guided wave (GW) and EMI on CMSP was first studied through the finite element method. Based on EMI and the mean absolute percentage deviation (MAPD), the selected damage indicator (DI), a probability‐weighted damage imaging algorithm are proposed and experimentally verified. The results indicate that due to the reflection and attenuation effects of stiffeners on GW, the signal characteristics of damage scattering waves are contaminated, making it difficult to quantitatively characterize the damage from GW signals through DIs. MAPD is positively correlated with the damage degree and has consistency in characterizing the signal of different PZTs under the same working condition. The feasibility and accuracy of the proposed algorithm are verified through experiments which show a strong engineering application capability.
Nonlinear Attitude and Altitude Trajectory Tracking Control of a Bicopter UAV in Geometric Framework
Authors: Vundela Vijay Reddy , Muralidharan Vijay
Published: May 2024

In this paper, we deal with a Bicopter drone that has two thrusters and two tilting servos. Both the position and attitude dynamics of Bicopter are globally expressed on the Special Euclidean group SE3. A simple control allocation method is proposed to map between the control wrench and actuator inputs for the Bicopter. A geometric nonlinear attitude and altitude tracking controller is developed for the Bicopter and the asymptotic stability analysis is performed using the Lyapunov method for the closed-loop nonlinear system. The performance of the proposed altitude and attitude stabilization controller is validated through experimental hardware developed in-house. The attitude controller performance is validated through simulations and shown to be comparable against an linear matrix inequality-based control law.
Skeletal Myoblast Cells Enhance the Function of Transplanted Islets in Diabetic Mice
Authors: Kado Takeshi , Tomimaru Yoshito , Kobayashi Shogo , Harada Akima , Sasaki Kazuki , Iwagami Yoshifumi , Yamada Daisaku , Noda Takehiro , Takahashi Hidenori , Kita Shunbun , Shimomura Iichiro , Miyagawa Shigeru , Doki Yuichiro , Eguchi Hidetoshi
Published: May 2024

Islet transplantation (ITx) is an established and safe alternative to pancreas transplantation for type 1 diabetes mellitus (T1DM) patients. However, most ITx recipients lose insulin independence by 3 years after ITx due to early graft loss, such that multiple donors are required to achieve insulin independence. In the present study, we investigated whether skeletal myoblast cells could be beneficial for promoting angiogenesis and maintaining the differentiated phenotypes of islets. In vitro experiments showed that the myoblast cells secreted angiogenesis‐related cytokines (vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), and stromal‐derived factor‐1α (SDF‐1α)), contributed to maintenance of differentiated islet phenotypes, and enhanced islet cell insulin secretion capacity. To verify these findings in vivo, we transplanted islets alone or with myoblast cells under the kidney capsule of streptozotocin‐induced diabetic mice. Compared with islets alone, the group bearing islets with myoblast cells had a significantly lower average blood glucose level. Histological examination revealed that transplants with islets plus myoblast cells were associated with a significantly larger insulin‐positive area and significantly higher number of CD31‐positive microvessels compared to islets alone. Furthermore, islets cotransplanted with myoblast cells showed JAK‐STAT signaling activation. Our results suggest two possible mechanisms underlying enhancement of islet graft function with myoblast cells cotransplantation: “indirect effects” mediated by angiogenesis and “direct effects” of myoblast cells on islets via the JAK‐STAT cascade. Overall, these findings suggest that skeletal myoblast cells enhance the function of transplanted islets, implying clinical potential for a novel ITx procedure involving myoblast cells for patients with diabetes.