bluuebunny/crossref_metadata_2025 huggingface dataset:
Cobalt Formate, a Functional MOF: Electrocatalytic Water Oxidation
Authors: Ravi Athira , Nasani Rajendar , Das Samar K.
Published: May 2022

Cobalt formate dihydrate, Co(HCOO)[Formula: see text]H2O (Co-MOF), a known crystalline substance, is a three-dimensional coordination polymer. The compound crystallizes in a monoclinic space group [Formula: see text]. In this work, we are reporting a unique synthesis method to prepare this MOF without using any formate salt or formic acid. The source of formate in compound Co-MOF is dimethylformamide (DMF) solvent used in the relevant synthesis. This metal–organic framework (MOF) containing compound, which can be described as a functional MOF, has recently been exploited for hydrogen isotope separation. This functional material has never been used as an electrocatalyst. In this work, we have demonstrated that this water insoluble compound Co-MOF can be used as heterogeneous electrocatalyst for oxygen evolution reaction (OER) by water oxidation at neutral pH. An overpotential of 275.5[Formula: see text]mV versus RHE was required to attain a current density of 1[Formula: see text]mAcm[Formula: see text]. The relevant Faradic efficiency (89.93%) and the turn over frequency (TOF) of 0.277[Formula: see text]s[Formula: see text] make the material an efficient electrocatalyst for water oxidation to molecular oxygen at neutral pH.
An Empirical Study of Older Adult’s Voice Assistant Use for Health Information Seeking
Authors: Brewer Robin , Pierce Casey , Upadhyay Pooja , Park Leeseul
Published: May 2022

Although voice assistants are increasingly being adopted by older adults, we lack empirical research on how they interact with these devices for health information seeking. Also, prior work shows how voice assistant responses can provide misleading or inaccurate information and be harmful particularly in health contexts. Because of increased health needs while aging, this paper studies older adult’s (ages 65+) health-related voice assistant interactions. Motivated by a lack of empirical evidence for how older adults approach information seeking with emerging technologies, we first conducted a survey of n = 201 older adults to understand how they engage voice assistants compared to a range of offline and digital sources for health information seeking. Findings show how voice assistants were used for confirmatory health queries, with users showing signs of distrust. As much prior work focuses on perceptions of voice assistant use, we conducted scenario-based interviews with n = 35 older adults to study health-related voice assistant behavior. In interviews, participants engaged with different health topics (flu, migraine, high blood pressure) and scenario types (symptom-driven, behavior-driven) using a voice assistant. Findings show how conversational and human-like expectations with voice assistants lead to information breakdowns between the older adult and voice assistant. This paper contributes a nuanced query-level analysis of older adults’ voice-based health information seeking behaviors. Further, data provide evidence for how query reformulation happens with complex topics in voice-based information seeking. We use our findings to discuss how voice interfaces can better support older adults’ health information seeking behaviors and expectations.
Relational Agents for the Homeless with Tuberculosis Experience: Providing Social Support Through Human–agent Relationships
Authors: Jang Yi Hyun , Im Soo Han , Kang Younah , Baek Joon Sang
Published: May 2022

In
human–computer interaction (HCI)
research,
relational agents (RAs)
are increasingly used to improve social support for vulnerable groups including people exposed to stigmas, alienation, and isolation. However, technical support for
tuberculosis (TB)
patients, one such vulnerable group, remains insufficient due to the nature of the infectious disease and difficulties in accessing the homeless community. To derive design considerations for developing RAs targeting homeless TB patients, we conducted an empirical study on the patients. Data were collected through participatory observations and interviews and were processed using deductive thematic analysis. The patients’ environmental and behavioral characteristics were classified, which showed that understanding these factors in the design of an RA is important because the patients’ perception, attitudes, and expectations towards the agent are shaped by (and also shape) their environmental and behavioral characteristics, which consequently affect the nature of relationships formed between them. Therefore, we drew the following design considerations: (1) protection of privacy is a prerequisite to the use of an RA for homeless TB patients and can be addressed from both short-term (technical) and long-term (sociotechnical) perspectives; (2) the homeless group emphasized affective support from the agent, suggesting that relationships per se are already valuable to people who have been socially isolated and stigmatized; (3) consideration of the past memories in selecting social cues can facilitate the exchange of affective expressions in user–agent interaction; and (4) an RA should clarify to its interlocuters its identity as a machine to avoid confusing people with low technological literacy.
Monitoring Constraints and Metaconstraints with Temporal Logics on Finite Traces
Authors: De Giacomo Giuseppe , De Masellis Riccardo , Maggi Fabrizio Maria , Montali Marco
Published: May 2022

Runtime monitoring is a central operational decision support task in business process management. It helps process executors to check on-the-fly whether a running process instance satisfies business constraints of interest, providing an immediate feedback when deviations occur. We study runtime monitoring of properties expressed in
ltl

f

, a variant of the classical
ltl
(Linear-time Temporal Logic) that is interpreted over finite traces, and in its extension
ldl

f

, a powerful logic obtained by combining
ltl

f

with regular expressions. We show that
ldl

f

is able to declaratively express, in the logic itself, not only the constraints to be monitored, but also the de facto standard
rv
-LTL monitors. On the one hand, this enables us to directly employ the standard characterization of
ldl

f

based on finite-state automata to monitor constraints in a fine-grained way. On the other hand, it provides the basis for declaratively expressing sophisticated metaconstraints that predicate on the monitoring state of other constraints, and to check them by relying on standard logical services instead of ad hoc algorithms. We then report on how this approach has been effectively implemented using Java to manipulate
ldl

f

formulae and their corresponding monitors, and the
RuM
rule mining suite as underlying infrastructure.
Challenges, experiments, and computational solutions in peer review
Authors: Shah Nihar B.
Published: May 2022

Improving the peer review process in a scientific manner shows promise.
Government as a Brain: How Can Governments Better Understand, Think, Create, and Remember, and Avoid the Traps of Collective Stupidity Both in Emergencies and Normal Times
Authors: Mulgan Geoff
Published: May 2022

Governments are evolving new ways to think, combining observation, memory, analysis, models, and creativity. This article describes how they think, how the COVID crisis has accelerated innovation in new ways of thinking, the use of metaphors to understand these processes, the role of democracy and civil society, and the new skills needed.
A Survey on Temporal Sentence Grounding in Videos
Authors: Lan Xiaohan , Yuan Yitian , Wang Xin , Wang Zhi , Zhu Wenwu
Published: May 2022

Temporal sentence grounding in videos (TSGV), which aims at localizing one target segment from an untrimmed video with respect to a given sentence query, has drawn increasing attentions in the research community over the past few years. Different from the task of temporal action localization, TSGV is more flexible since it can locate complicated activities via natural languages, without restrictions from predefined action categories. Meanwhile, TSGV is more challenging since it requires both textual and visual understanding for semantic alignment between two modalities (i.e., text and video). In this survey, we give a comprehensive overview for TSGV, which (i) summarizes the taxonomy of existing methods, (ii) provides a detailed description of the evaluation protocols (i.e., datasets and metrics) to be used in TSGV, and (iii) in-depth discusses potential problems of current benchmarking designs and research directions for further investigations. To the best of our knowledge, this is the first systematic survey on temporal sentence grounding. More specifically, we first discuss existing TSGV approaches by grouping them into four categories, i.e., two-stage methods, single-stage methods, reinforcement learning-based methods, and weakly supervised methods. Then we present the benchmark datasets and evaluation metrics to assess current research progress. Finally, we discuss some limitations in TSGV through pointing out potential problems improperly resolved in the current evaluation protocols, which may push forwards more cutting-edge research in TSGV. Besides, we also share our insights on several promising directions, including four typical tasks with new and practical settings based on TSGV.
Dynamic Transfer Exemplar based Facial Emotion Recognition Model Toward Online Video
Authors: Bi An-Qi , Tian Xiao-Yang , Wang Shui-Hua , Zhang Yu-Dong
Published: May 2022

In this article, we focus on the dynamic facial emotion recognition from online video. We combine deep neural networks with transfer learning theory and propose a novel model named DT-EFER. In detail, DT-EFER uses GoogLeNet to extract the deep features of key images from video clips. Then to solve the dynamic facial emotion recognition scenario, the framework introduces transfer learning theory. Thus, to improve the recognition performance, model DT-EFER focuses on the differences between key images instead of those images themselves. Moreover, the time complexity of this model is not high, even if previous exemplars are introduced here. In contrast to other exemplar-based models, experiments based on two datasets, namely, BAUM-1s and Extended Cohn–Kanade, have shown the efficiency of the proposed DT-EFER model.
(Digital Presentation) Calculation of the Energy Band Diagram and Estimation of Electronic Transport Parameters of Metastable Amorphous Ge2Sb2Te5
Authors: Kashem Md Tashfiq Bin , Muneer Sadid , Adnane Lhacene , Dirisaglik Faruk , Gokirmak Ali , Silva Helena
Published: May 2022

We calculate critical electronic conduction parameters of the amorphous phase of Ge2Sb2Te5 (GST), a common material used in phase change memory. We estimate the room temperature bandgap of metastable amorphous GST to be Eg (300K) = 1.84 eV based on a temperature dependent energy band model. We estimate the free carrier concentration at the melting temperature utilizing the latent heat of fusion to be 1.47 x 1022 cm-3. Using the thin film melt resistivity, we calculate the carrier mobility at melting point as 0.187 cm2/V-s. Assuming that metastable amorphous GST is a supercooled liquid with bipolar conduction, we compute the total carrier concentration as a function of temperature and estimate the room temperature free carrier concentration as p(300K) ≈ n(300K) = 1.69×1017 cm-3. Free electrons and holes are expected to recombine over time and the stable (drifted) amorphous GST is estimated to have p-type conduction with p(300K) ≈ 6×1016 cm-3.
Low-Temperature Rough-Surface Wafer Bonding with AlN/AlN Via Oxygen Plasma Activation
Authors: Huang Wei-Chi , Nien Shao-Ming , Ruan Jian-Long , Kuo Yang-Kuao , Lee Benjamin T.-H.
Published: May 2022

We demonstrate breaking through the main obstacle to achieve perfect wafer bonding: the requirement of the surface needs to be very flat and smooth. Strictly, the roughness must be less than 0.5 Å. We use sintered aluminum nitride as an example. AlN is a ceramic material with excellent dielectric and thermal properties and is usually used in the fields of microelectronics and energy. Despite CMP polishing, the high roughness (rms> 10 nm) of AlN wafers due to voids formed in sintering cannot meet the surface requirements for direct wafer bonding (rms < 5 Å). We present that bonding an AlN to another AlN with a high roughness surface can be achieved by design bonding processing. First, we used oxygen plasma to activate the hydrophobic rough surface to become a hydrophilic surface to introduce strong capillary action. Then, both surfaces of the bonded AlN/AlN pair were reacted with bonding species (OH-). The reaction was strengthened via electron transfer caused by clamping the bonded AlN/Al pair. Finally, low-temperature annealing (<150°C) was performed on the bonded AlN/AlN pair to synthesize Al2O3 at the bonding interface. After annealing at 150°C for 4 hours, the bonding interface of the AlN bonding pair was observed with scanning electron microscopy (SEM), as shown in Figure 1. There is a transition layer between the bonding surfaces, in which the nitrogen concentration decreases and the oxygen concentration increases significantly. Alumina layer is formed by hydrolysis and dehydration, which acts as a bridge to firmly connect the two AlN wafers.
(Invited) Innovations in Transistor Architecture and Device Connectivity Options for Advanced Logic Scaling
Authors: Veloso Anabela , Eneman Geert , Simoen Eddy , Cretu Bogdan , De Keersgieter An , Jourdain Anne , Horiguchi Naoto
Published: May 2022

We report on vertically stacked nanosheet (NS) FET devices as the most promising candidates to replace finFETs, discussing some of their key features and potential extension and/or alternative options to help preserve the power, performance, area, and cost (PPAC) logic roadmap for advanced sub-5nm technology nodes, being also attractive for cold computing. In addition, given the increased complexity and cost in back-end-of-line processing, to take full advantage of the scaling performance benefits at transistor level it has also become ever more pressing to address signal and power wiring bottlenecks. The concept of moving power delivery to the wafer’s backside has been gaining traction and we will thus also explore it in this work by combining logic and 3D technologies and assess its feasibility by evaluating the impact of 3D processing on device characteristics.
(Invited, Digital Presentation) Improved Reliability of 4H-SiC Metal-Oxide-Semiconductor Devices Utilising Atomic Layer Deposited Layers with Enhanced Interface Quality
Authors: Renz Arne Benjamin Benjamin , Vavasour Oliver J , Gammon Peter Michael , Li Fan , Dai Tianxiang , Baker Guy W C , Grant Nicholas E , Murphy John D , Mawby P. A. , Shah Vishal Ajit , Gott James
Published: May 2022

An investigation into the effect of deposition, growth and conditioning of the SiO2/SiC interface in MOS capacitors is performed, where the enhancement of reliability is characterised. Various methods of oxide formation are compared: ALD, LPCVD and thermally grown. ALD-deposited oxides were post-deposition annealed in nitrous oxide ambient, resulting in average flatband voltages of 0.63 V and low D
IT
levels, down to 7 x 1011 cm-2 eV-1 at EC-ET =0.2 eV. These samples also outperformed their counterparts in terms of high leakage and constant voltage TDDB performance, which was done at 175°C, averaging breakdown electric fields of 9.84 MV/cm and a 63% failure stress time of 11220 s when stressed at 8 MV/cm.
Control Of Particle Adhesion On InGaAs Surface In Basic Solution By The Addition Of Cationic Surfactant
Authors: Lee Junwoo , Lim Sangwoo
Published: May 2022

The adhesion of silica particles on an InGaAs surface in a 1/1/100 NH4OH–H2O2–H2O mixture (APM) solution was investigated. To control the particle adhesion on InGaAs surface, hexadecyltrimethylammonium bromide (CTAB) was added to the APM solution at concentrations of 10-4–10-2 M, and its effect was examined. To understand the adhesion behavior of silica particles on the InGaAs surface in the APM solution with the addition of CTAB, Lifshitz–van der Waals energy, acid–base interaction energy, and electrostatic energy were estimated. In addition, energy barrier was calculated from the changes in those energies. It was found that the behavior of the energy barrier was strongly related to the adhesion behavior of the silica particles on the InGaAs in the APM solution with different concentrations of CTAB. Therefore, the addition of CTAB changes the interaction force and the energy for particle to adhere to the InGaAs surface.
(Invited) Metallic Impurity Control in Silicon Processing
Authors: Polignano Maria , Borionetti Gabriella
Published: May 2022

The performances of a few techniques for the analysis of metal contamination in silicon are reviewed. The chemical dissolution of a polysilicon gettering layer associated to ICP-MS (Inductively Coupled Plasma - Mass Spectroscopy) analysis, TXRF (Total Reflection X-Ray Fliuorescence) Recombination lifetime measurement techniques, DLTS (Deep Level Transient Spectroscopy) and micro-photoluminescence analyses are compared. A few case studies are discussed to test the ability of these techniques in detecting contaminants with different properties as silicon impurities. The results reported in this paper show that it is not possible to define a unique recipe that can be applied in all cases. Different approaches are required depending, on one hand, on the contaminant diffusivity and solubility, and, on the other hand, on the process step to be monitored. Finally, we show that the device itself can be a sensitive monitor of metal contamination.
Ice-VII-like Structure Observed By XRD in Water Confined in Silica Nanoholes
Authors: Vereecke Guy , Kenis Karine , Wostyn Kurt , Sanchez Efrain Altamirano
Published: May 2022

In advanced semiconductor manufacturing, deep hydrophilic nanoholes are found in various applications, which require a wet clean after patterning. However, wetting of high aspect ratio nanoholes was showed to be incomplete for non-settled reasons. In this study, X-ray diffraction (XRD) was used to characterize water confined in deep nanoholes with 20 nm diameter. Long XRD measurements were made possible by the anomalous capillary condensation occurring in these nanoholes, which was proved by Attenuated Total Reflection – Fourier Transformed Infra-Red measurements. Condensation occurred in nanoholes submitted to the clean-room air with a relative humidity (RH) of about 40%, while no condensation was observed under a N2 flow with a RH of about 30%. XRD measurements showed the presence of small peaks varying as a function of the XR incidence angle, which were not present in the Si and oxide references. These peaks gave evidence for structuring of water confined in nanoholes.
(Digital Presentation) Research on Single Wafer RCA Clean in High Aspect Ratio Trenches
Authors: Chen Fuping , Zhang David Wei , Wei Xiongfei , Zhang Xiaoyan , Liu Feng , Henry Sally Ann , Hu Haibo , Yao Liang , Chen Wei , Shou Xiaodong , Cui Yao
Published: May 2022

High aspect ratios trench are commonly used in shallow trench isolation (STI) or Gate Poly-silicon structures by dry etching of a silicon substrate. During the dry etching process, polymerization residues are produced inside the trench. These polymerization residues must be removed before the next deposition process. Watermarks might also form by poor drying after the wet cleaning process of high aspect ratio structures, which can seriously affect the next process. In this paper, we show the performance of single wafer RCA cleaning technology in high aspect ratio structures. Polymer residues can be removed by diluted HF and SC1 with megasonic technology, without the appearance of watermarks after drying. This study focuses on polymerization residues and watermarks using inline defect detection to qualify the performance of single wafer RCA clean. Yield is the final verification for proving the single wafer RCA clean.
(Digital Presentation) Two-Step Wet Clean for HKMG TiAl Protection and Polymer-Free
Authors: Chen Tianrui , Tu Wutao , Zhang Haiyang
Published: May 2022

In this paper, a two-step clean method for TiAl protection is discussed, which could improve TiAl damage and make etch-polymer clean. Using a kind of organic alkaline chemical, marked chemical k, before traditional HF clean, the TiOx passivation layer forms on the surface TiAl, then HF cleans etch-by-product polymer. The TiAl loss by HF is reduced to 14% after chemical k treatment. The risk of TiAl damage is hence much improved.
(Digital Presentation) An Advanced Process Control Scheme for Fin Etching Process in Front-End-of-Line FinFET High Volume Production
Authors: Song Jia , Ke Xing , Zhang En-Ning , Ji Shiliang , Zhao Zhenyang , Zheng Chongchong , Li Zhengning , Zhang Hai-Yang
Published: May 2022

As FinFET scales down to advanced technology nodes, Fin profile and Critical Dimension (CD) control are becoming a huge challenge due to the increased number of processes. For a stable wafer-to-wafer CD performance, Advanced Process Control (APC) system is widely deployed in high volume manufacturing production. In this work, we present a novel implementation of an APC-based fuzzy control system in the Fin etching process within the widely-used Self-aligned Quadruple Patterning (SaQP) scheme. Feed-forward APC is applied to the two processes: 1) Atomic Layer Deposition (ALD) process for fin hard-mask etching and 2) fin etching process with fuzzy control. With the deployment of the APC system, the inline metrology variation performance of Fin CD improved from ±3.5% to ±1.8%. The Cp and Cpk are increased by 29% and 32%, for various key inline parameters. The APC-based fuzzy control scheme shows great potential for the advanced nodes.
Operating Proton Exchange Membrane Fuel Cells at a Constant Relative Humidity
Authors: Bielefeld Nikolaj M. , Sørensen Rasmus D. , Jørgensen Mikkel , Kure Kristoffer S. , Berning Torsten
Published: May 2022

This study investigates the possibility of operating a proton exchange membrane fuel cell at a constant humidity of 100% from cathode inlet to cathode outlet. Employing the Engineering Equation Solver (EES), a model has been developed where the cathode channel flow is calculated via the discretized Hagen-Poiseuille equation. The stoichiometric flow ratio such that the decrease in the RH caused by the pressure drop is balanced by the addition of water due to the electrochemical reaction is calculated. Results show that in many cases the calculated stoichiometry is too low to be viable for a straight channel flow field. However, reducing the temperature yields acceptable stoichiometric flow ratios. The channel geometry plays a critical role, and shorter and deeper channels are preferable. In a refined version of the model, the limiting current density is calculated to avoid concerns about the low stoichiometric flow ratios.
Hybrid Electrocatalysts Composed of PtSn, Ru or PtRu Nanoparticles for Low-Temperature Oxidation of Dimethyl Ether Fuel
Authors: Rytelewska Beata , Rutkowska Iwona A. , Kulesza Pawel J.
Published: May 2022

Electrocatalytic activity of Vulcan-supported PtSn (PtSn/C) nanostructured alloys toward electrooxidation of dimethyl ether (DME), a potential small-organic-molecule fuel, has been significantly enhanced in acid medium (0.5 mol dm-3 H2SO4) by decorating PtSn/C with bimetallic PtRu nanoparticles modified with phosphododecatungstic acid (PtRu/PW12). The enhancement effect concerns both shifting the onset potential for the DME-oxidation toward less positive values and increase of the DME electrocatalytic current densities recorded under both cyclic voltammetric and chronoamperometric conditions. In that respect, the Ru-oxo species originating from PtRu additives seem to support activity of Sn co-catalytic sites interacting with Pt within the PtSn heterogenous alloy. The polytungstate adsorbates on nanoparticles facilitate their distribution at the electrocatalytic interface, as well as they interact competitively with the CO adsorbates at noble metal catalytic sites. The hybrid materials composed of PtSn/C decorated with PtRu nanoparticles modified with PW12 seem to act as multifunctional nanoreactors during electrooxidation of DME.
Bifunctional Platinum-Free Mixed Metal Oxygen Electrocatalysts Based on Naturally Abundant Peat
Authors: Teppor Patrick , Jäger Rutha , Härmas Meelis , Aruväli Jaan , Volobujeva Olga , Koppel Miriam , Lust Enn
Published: May 2022

Several mixed metal oxygen electrocatalysts based on combinations of Fe, Co, and Ni were synthesized from naturally abundant well-decomposed peat. The desired composition of the materials was confirmed with SEM-EDS and the formed alloys were identified by XRD. The materials were then studied as catalysts for the oxygen reduction and evolution reactions in alkaline media using the rotating disc electrode method. It was observed that the catalysts formed an array of FeCo/PDC > FeNi/PDC > FeCoNi/PDC according to their oxygen reduction onset potential values. High oxygen evolution activity comparable to IrO2 was exhibited by the materials. Consequently, excellent bifunctional activity comparable to data from the literature was reached with all three synthesized catalysts. The best bifunctional activity was achieved with a catalyst based on Fe and Co which was evident in a low ΔE value of 0.75 V.
(Digital Presentation) Temperature-Dependent Study for Electrochemical Surface Area on a Catalyst Layer Used in a PEFC
Authors: Espinoza R. , Munoz Kevin , Santana Jordy , Espinoza Andaluz Mayken , Andersson Martin
Published: May 2022

The total of catalytic particles is often unavailable to participate in the electrochemical reactions in a PEFC, which limits the PEFC performance. The electrochemical surface area (ECSA) becomes an important metric to diagnose the catalyst layer's performance and evaluate the development of new electrode materials to achieve better overall efficiency. This work intends to analyze the effects of a temperature sweep on the ECSA and determine the best model that fits the trend based on obtained results from in-situ cyclic voltammetry (CV) tests. The experiment was carried out using a single PEFC of 25 cm2 with a catalyst layer of 0.5mg Pt/cm2 and Nafion® 112 membrane, using hydrogen and nitrogen as reactant gases at 100% relative humidity (RH). The results show a loss of ECSA about 14% in the temperature range evaluated. Besides, it was found that a linear function is adequate to model the correlation based on the experimental data obtained.
(Digital Presentation) Corrosion Behavior of Aluminum-Carbon Composite Bipolar Plates in Polymer Electrolyte Membrane Fuel Cells
Authors: Jahan Aklima , Alam Md. Ashraful , Yonezawa Sekai , Suzuki Eiichi , Yashiro Hitoshi
Published: May 2022

Bipolar plate, aluminum is one of the most promising alternatives that can capable of uniform distribution of reactive gases over active areas and removal of the heat and exhaust water from the PEMFC. In this work, PEM fuel cell was operated using the bipolar plate constructed of two materials: a channel former made of glassy carbon and a gas isolation plate made of aluminum. Aluminum gas isolation plate at cathode side remained glossy after even1000 h cell operation. In contrast, an oxide layer with a thickness of about 1 μm was formed on the gas isolation plate at anode side. In the simulated corrosion test, a thick oxide layer was formed when aluminum was immersed in water while only a thin oxide layer was formed in the saturated water vapor. The microscopic images, scanning electron microscopy (SEM) images, energy dispersive X-ray (EDX) spectra and transmission electron microscopy (TEM) images were taken to evaluate the surface morphology, elemental composition and other analyses.
Proton Exchange Membrane Fuel Cell Flow Field Configuration: Modelling and Experimental Verification
Authors: Tolj Ivan , Penga Zeljko , Bosnic Petar , Radica Gojmir
Published: May 2022

Improper design of flow field channels may lead to water stagnation and flooding and may therefore lead to a poor fuel cell performance. The main purpose of this work is to investigate liquid water formation inside the flow field of the proton exchange membrane (PEM) fuel cell and to find optimal flow field configuration such as: number of channels, channel width to rib ratio and channel depth. To achieve this goal advanced numerical model of PEM fuel cell was developed. Model was simulated in Fluent, using computational fluid dynamics (CFD). Based on the obtained simulation results, graphite bipolar plate with optimal channel design was machined, integrated into the single PEM fuel cell unit, and experimentally tested.
3D Printed Carbon Aerogels for Polymer-Electrolyte Fuel Cells
Authors: Santamaria Anthony D. , Chandrasekaran Swetha , Philbrick Oliver , Worsley Marcus Andre
Published: May 2022

Carbon aerogels (CA) are known for ultra-low density, very high surface area, fine porous structure, and excellent electrical conductivity. Recent advances in high resolution 3D printing at LLNL enable the manufacturing of complex structured CA electrodes which have been demonstrated in electrolysis, flow battery, and supercapacitor applications. Polymer-electrolyte fuel cells (PEFC) may be an excellent candidate for these materials/methods as designers seek to optimize membrane-electrode assemblies to achieve higher efficiencies. A major challenge to PEFC design is two-phase flow due to water production which causes pore flooding and leads to cell instability and degradation. To mitigate these effects, groups have investigated the creation of liquid specific pathways in the porous layers to alleviate liquid buildup and enhance gas diffusion. While some progress has been made, traditionally manufactured GDLs, which consist of randomly distributed carbon fibers, are limiting. 3D printed CAs are a promising solution as complex macroporous electrode structures can be manufactured out of micro and nano porous filaments with a high level of control. Additionally, the process may allow for the consolidation of multiple layers (MPL, GDL, & flow channels) into a single printed architecture. In this work various CA lattice structures were printed using a direct ink write (DIW) method and liquid breakthrough pressures were measured to demonstrate the ability to tune the water pathways to achieve specific pressure thresholds. A discussion of the prospects for printed CA electrodes in PEFC will focus on material properties, synthesis techniques, and current challenges.
(Digital Presentation) Effects of Catalyst Dimension Parameters on Local Oxygen Transport in Cathode Catalyst Layer of Proton Exchange Membrane Fuel Cell
Authors: Li Xiang , Tang Fumin , Li Bing , Dai Haifeng , Chang Guofeng , Ming Pingwen
Published: May 2022

Improving the performance of proton exchange membrane fuel cells (PEMFCs) can help accelerate their large-scale commercial application. In this paper, an agglomerate model is proposed and developed by coupling a one-dimensional local oxygen transport model with a one-dimensional multiphase non-isothermal fuel cell sub-model to study the influences of catalyst dimension parameters (Pt radius, Pt average dispersity, carbon radius) on local oxygen transport and cell performance. And this elaborate model shows that the smaller Pt radius, carbon radius, and the higher Pt average dispersity can reduce the transport distance of oxygen molecules from the pores to the active sites, and then decrease the local resistance. Based on the above understanding, the optimum performance of the optimized cell with a Pt loading of 0.2 mg cm-2 is improved by 22%, slightly higher than the original cell with a Pt loading of 0.4 mg cm-2, which achieves a 50% reduction in Pt loading while maintaining the cell performance. This research will give a guide for improving cell performance.
Core-Shell Enhanced Single Particle Model for lithium iron phosphate Batteries: Model Formulation and Analysis of Numerical Solutions
Authors: Pozzato Gabriele , Takahashi Aki , Li Xueyan , Lee Donghoon , Ko Johan , Onori Simona
Published: May 2022

In this paper, a core–shell enhanced single particle model for lithium iron phosphate (

L

i

F

e

P

O

4

) battery cells is formulated, implemented, and verified. Starting from the description of the positive and negative electrodes charge and mass transport dynamics, the positive electrode intercalation and deintercalation phenomena and associated phase transitions are described with the core–shell modeling paradigm. Assuming two phases are formed in the positive electrode, one rich and one poor in lithium, a core-shrinking problem is formulated and the phase transition is modeled through a shell phase that covers the core one. A careful discretization of the coupled partial differential equations is proposed and used to convert the model into a system of ordinary differential equations. To ensure robust and accurate numerical solutions of the governing equations, a sensitivity analysis of numerical solutions is performed and the best setting, in terms of solver tolerances, solid phase concentration discretization points, and input current sampling time, is determined in a newly developed probabilistic framework. Finally, unknown model parameters are identified at different C-rate scenarios and the model is verified against experimental data.
An Efficient Electrical Network Model for Computing Electrochemical State Distributions in a Spirally Wound Lithium-Ion Cell
Authors: Christensen Jake , Patnaik Somani , Cook David , Albertus Paul
Published: May 2022

The electrical design of a lithium-ion battery, including current collector dimensions and tabbing layout, can have a significant impact on its performance and aging behavior. This work describes a coupled electrochemical + electrical network model to quantify the impact of current collector resistance on performance, current distribution, and internal state heterogeneity in cells with cylindrically wound jellyrolls. We observe that, despite apparently ohmic behavior, the current collector impedance in cells with single- (or few-) tab arrangements tends to drive nonuniformity of current and electrochemical states throughout the jellyroll. This nonuniformity can give rise to enhanced and nonuniform lithium plating and other aging processes, depending on design and operating conditions.
Role of Functional Groups in an Ionic Liquid Decorated Au(111) Surface for CO2 Capture and Activation: A First Principle Approach
Authors: Kamalakannan Shanmugasundaram , Maiyelvaganan K. Rudharachari , Prakash Muthuramalingam
Published: May 2022

A heterogeneous catalytic environment plays a major role to decide the catalytic activation and conversion of the CO2 molecule at the interface. For this, we have chosen functionalized 1-ethyl-3-methylimidazolium cation (i.e. [EMIm-Z]+[X]−; Where, Z = NH2 and CF3) with two different anions (i.e. [X]− = [DCA]− and [SCN]−). Our results reveal that the electron-donating groups at the interface can effectively activate and converts CO2 to radical anion. But the electron-withdrawing (i.e. –CF3) substituent lowers the binding strength of CO2. Besides, the adsorption and activation mechanism of CO2 at the interface is directly influenced by the involvement of the –NH2 functional groups in the ([EMIm]+) cation. It is identified that the different types of intermolecular interactions between the CO2 and interface. Such as, (i) O = C = O····H(–NH2) (ii) O=C=O····H (–CH3)) (iii) O=C=O····F(–CF3). Our work provides a clear picture of the role of the functional group in the interfacial medium for the activation of CO2.
Review—Recent Advancements in Electrochemical Sensors for 4-Aminoquinoline Drugs Determination in Biological and Environmental Samples
Authors: Matrouf M. , Loudiki A. , Azriouil M. , Laghrib F. , Farahi A. , Bakasse M. , Saqrane S. , Lahrich S. , El Mhammedi M. A.
Published: May 2022

4-Aminoquinoline including Hydroxychloroquine (HCQ), amodiaquine (AQ), Chloroquine (CQ) are a quinoline with an amino group at the 4th position with a basic side chain. They are generally used as antimalarial medications. HCQ and CQ are recommended by the World Health Organization on march 2020 the use as a possible treatment to coronavirus (COVID–19). Long-term of 4-aminoquinoline drugs administration can be associated with toxic side-effects on the outer retina and the retinal pigment epithelium. Therefore, their determination in biological samples is important. Several methods have been used for 4-Aminoquinoline compounds analysis, such as spectrophotometry, immunological, electrophoresis, chromatography and electroanalytical methods. Electrochemical methods are more preferable because they are simple, quick analysis and more sensitive performance. Up to now, numerous electrochemical methods have been used to detect those drugs. Nevertheless, the utilization of later techniques is limited. Therefore, this review describes different electrochemical sensors, which are used for 4-aminoquinoline electroanalysis in complex matrices such as pharmaceuticals and biological fluids. For this, the fundamental analytical performance of the chosen sensors is investigated. The selectivity and oxidation mechanisms for 4-aminoquinoline reported in the literature were discussed. Also, the application of these sensors for 4-aminoquinoline monitoring in biological and environmental samples is reported.
Evaluation of Structural and Optical Properties of Nanocrystalline Cubic Y2O3 Phase Materials via Combustion Method Using Different Fuels
Authors: Marjuka A. Saliha , Balamurugan S. , Ashika S. A. , Fathima T. K. Sana
Published: May 2022

In this work, we have carried out combustion synthesis of nanocrystalline Y2O3 materials using hexamine, polyethylene glycol(200) (PEG(200)), and ethylene glycol (EG) as fuels. In addition, the impact of mechanical stirring of commercial Y2O3 powder with various dilutions of PEG(200) with distilled water as a solvent was also examined. The as-prepared combustion product of the hexamine is significantly different from other fuels (PEG(200) and EG). The annealed combustion products crystallize in the pure cubic Y2O3 phase. The combustion product of PEG(200) reveals a maximum weight loss of ∼46% at 800 °C in the TG curve. The UV–vis-NIR features of different samples show quite interesting results. The Eg values obtained from the Tauc plots are found in the range of 5.48 to 5.71 eV for the different samples. The observed strong FTIR band at 560 ∼ 415 cm−1is owing to the vibrational Y–O bond in the present series samples. The Raman spectra show the highest intensity peak at wavenumber 374 cm−1is owing to the Fg vibrational mode of the Y2O3phase. Agglomerated nature of nanoparticles is seen in the Y2O3 phase samples obtained from EG and hexamine as fuels. The PEG-derived Y2O3 nanomaterials exhibit rather a high reflectance in the NIR region quite comparable to the NIR tendency of the mechanically stirred Y2O3 samples. Thus, the present processed nanocrystalline Y2O3 materials are efficient for solar reflective pigment application in the NIR industry.
Impact of breakthrough COVID-19 cases during the omicron wave on vascular health and cardiac autonomic function in young adults
Authors: Skow Rachel J. , Nandadeva Damsara , Grotle Ann-Katrin , Stephens Brandi Y. , Wright Alexis N. , Fadel Paul J.
Published: May 2022

We show for the first time that breakthrough cases of COVID-19 during the Omicron wave does not impact vascular health and cardiac autonomic function in young adults. These are promising results considering earlier research showing impaired vascular and autonomic function following previous variants of COVID-19. Collectively, these data demonstrate that the recent Omicron variant is not detrimental to cardiovascular health in young, otherwise healthy, vaccinated adults.
Photothermal Effect Based on Bionic Nanomaterials in the Treatment of Football Sports Injuries
Authors: Xing Jiarui , Li Huilin
Published: May 2022

As more and more people love football and participate in more and more football matches, the physical injuries in the confrontation are getting more and more serious. In recent years, bionic photothermal nanomaterials have shown great application potential in disease treatment. Biomimetic photothermal nanomaterials are functional and intelligent materials with special excellent performance that are designed and synthesized by using natural biomimetic principles. Photothermal therapy (PTT) technology is a new treatment technology in recent years. On the one hand, photothermal therapy technology can convert light energy into heat energy through photothermal conversion factor (PTCA). Molecular water‐soluble drugs penetrate into the skin to replace the existing injection administration methods with higher risk and low patient compliance and oral administration methods that generally cause first‐pass effects, improve the utilization and efficiency of drugs, and can give provide patients with better treatment. The purpose of this article is to explore the application of the photothermal effect of bionic nanomaterials in the treatment of football sports injuries. The method adopted in this paper is to synthesize different bionic photothermal nanomaterials and synthesize bionic photothermal nanomaterials that are fused with cell membranes, thereby promoting the application of photothermal therapy technology in the treatment of sports injuries; further, by synthesizing bionics wrapped by fusion membranes, photothermal nanomaterials introduce collaborative photothermal therapy technology. The experimental results show that the photothermal effect of nanobiomimetic materials is used to treat common injuries caused by football sports. Compared with traditional treatment methods, HA‐CuS gel and near‐infrared treatment are applied to the skin with the injured tissue of the experimental group. It dropped to 85.7% in 2 h then gradually dropped to 84.2%, and the recovery speed was significantly accelerated.
Anti-inflammatory and Tendon-Protective Effects of Adipose Stem Cell-Derived Exosomes with Concomitant Use of Glucocorticoids
Authors: Zhang Xuancheng , Li Ang , Han Kang , Zhang He , Huangfu Xiaoqiao , Huang Jinghuan , Jiang Jia , Zhao Jinzhong
Published: May 2022

Glucocorticoid (GC) injections are commonly used in clinical practice to relieve pain and improve function in patients with multiple shoulder disabilities but cause detrimental effects on rotator cuff tendons. Adipose stem cell-derived exosomes (ASC-Exos) reportedly recover impaired tendon matrix metabolism by maintaining tissue homeostasis. However, it is unclear whether additional treatment with ASC-Exos overrides the detrimental effects of GCs without interfering with their anti-inflammatory effects. Thus, we aimed to investigate the anti-inflammatory effect of ASC-Exos with GCs and protective effect of ASC-Exos against GC-induced detriments. The present study comprised in vitro and in vivo studies. In vitro inflammatory analysis revealed that ASC-Exos exerted a synergic anti-inflammatory effect with GCs by significantly decreasing secretion of proinflammatory cytokines by RAW cells and increasing secretion of anti-inflammatory cytokines. In vitro cytoprotective analysis showed that ASC-Exos overrode GC-induced detrimental effects on tenocytes by significantly improving GC-suppressed cellular proliferation, migration, and transcription of tenocytic matrix molecules and degradative enzyme inhibitors and significantly decreasing GC-induced cell senescence, apoptosis, and transcription of ROS and tenocytic degradative enzymes. In vivo studies revealed that additional ASC-Exo injection restored impairments in histological and biomechanical properties owing to GC administration. Collectively, these results suggest that ASC-Exos exert a stronger anti-inflammatory effect in combination with GCs, overriding their detrimental effects on rotator cuff tendons.
An Ensemble-Based Multiclass Classifier for Intrusion Detection Using Internet of Things
Authors: Rani Deepti , Gill Nasib Singh , Gulia Preeti , Chatterjee Jyotir Moy
Published: May 2022

Internet of Things (IoT) is the fastest growing technology that has applications in various domains such as healthcare, transportation. It interconnects trillions of smart devices through the Internet. A secure network is the basic necessity of the Internet of Things. Due to the increasing rate of interconnected and remotely accessible smart devices, more and more cybersecurity issues are being witnessed among cyber-physical systems. A perfect intrusion detection system (IDS) can probably identify various cybersecurity issues and their sources. In this article, using various telemetry datasets of different Internet of Things scenarios, we exhibit that external users can access the IoT devices and infer the victim user’s activity by sniffing the network traffic. Further, the article presents the performance of various bagging and boosting ensemble decision tree techniques of machine learning in the design of an efficient IDS. Most of the previous IDSs just focused on good accuracy and ignored the execution speed that must be improved to optimize the performance of an ID model. Most of the earlier pieces of research focused on binary classification. This study attempts to evaluate the performance of various ensemble machine learning multiclass classification algorithms by deploying on openly available “TON-IoT” datasets of IoT and Industrial IoT (IIoT) sensors.
Trend and Identification Analysis of Anti-investigation Behavior in Crime by Machine Learning Fusion Algorithm
Authors: Zhang Junshan , Lei Yang
Published: May 2022

In recent years, people’s living standards have gradually improved, and informatization has brought convenience, but it has also led to many criminal cases. Because the criminals’ criminal methods are diverse and constantly renovated, this feature is very prominent, and the illegal activities on the Internet are becoming more and more intense. Therefore, it is necessary to strengthen the research on the trend and identification of anti-investigation behavior in crime. The purpose of this paper is to study how to use machine learning fusion algorithms in the trend and identification of anti-investigation behavior in crime. This paper proposes a machine learning fusion algorithm and the basic conceptual knowledge of anti-investigation behavior in crime. The experimental results of this paper show that with the increasing number of criminal incidents, criminals’ means of committing crimes have also been improved. The anti-investigation capabilities of criminals have also become more sophisticated, which makes the work of law enforcement officers more difficult. The anti-investigation behavior of criminals in crime has many characteristics, among which the concealment reaches 54%-68%, and the virtuality reaches 68%-79%. It can be seen that the characteristics of criminals’ anti-investigation behavior provide a wider space for criminals to commit crimes. The advantage of the machine fusion algorithm is that the classification rules generated are easy to understand and have high accuracy, so it is very suitable for the classification and identification of anti-investigation behaviors in crimes. Therefore, it is urgent to use machine fusion algorithms to identify them.