bluuebunny/crossref_metadata_2025 huggingface dataset:
Point-of-care ultrasound for tuberculosis diagnosis in children: a Médecins Sans Frontières cross-sectional study in Guinea-Bissau
Authors: Moretó-Planas Laura , Sagrado María José , Mahajan Raman , Gallo Jonathan , Biague Evelize , Gonçalves Ramiro , Nuozzi Pablo , Rocaspana Merce , Fonseca Jamila Vieira , Medina Candida , Camará Miguel , Nadimpalli Adi , Alonso Beatriz , Llosa Augusto E , Heuvelings Lotje , Burza Sakib , Molina Israel , Ruby Lisa C , Stratta Erin , Bélard Sabine
Published: May 2023

Objective

Description of tuberculosis (TB)-focused point-of-care ultrasound (POCUS) findings for children with presumptive TB.

Design

Cross-sectional study (July 2019 to April 2020).

Setting

Simão Mendes hospital in Bissau, a setting with high TB, HIV, and malnutrition burdens.

Participants

Patients aged between 6 months and 15 years with presumptive TB.

Interventions

Participants underwent clinical, laboratory and unblinded clinician-performed POCUS assessments, to assess subpleural nodules (SUNs), lung consolidation, pleural and pericardial effusion, abdominal lymphadenopathy, focal splenic and hepatic lesions and ascites. Presence of any sign prompted a POCUS positive result. Ultrasound images and clips were evaluated by expert reviewers and, in case of discordance, by a second reviewer. Children were categorised as confirmed TB (microbiological diagnosis), unconfirmed TB (clinical diagnosis) or unlikely TB. Ultrasound findings were analysed per TB category and risk factor: HIV co-infection, malnutrition and age.

Results

A total of 139 children were enrolled, with 62 (45%) women and 55 (40%) aged <5 years; 83 (60%) and 59 (42%) were severely malnourished (SAM) and HIV-infected, respectively. TB confirmation occurred in 27 (19%); 62 (45%) had unconfirmed TB and 50 (36%) had unlikely TB. Children with TB were more likely to have POCUS-positive results (93%) compared with children with unlikely TB (34%). Common POCUS signs in patients with TB were: lung consolidation (57%), SUNs (55%) and pleural effusion (30%), and focal splenic lesions (28%). In children with confirmed TB, POCUS sensitivity was 85% (95% CI) (67.5% to 94.1%). In those with unlikely TB, specificity was 66% (95% CI 52.2% to 77.6%). Unlike HIV infection and age, SAM was associated with a higher POCUS-positivity. Cohen’s kappa coefficient for concordance between field and expert reviewers ranged from 0.6 to 0.9.

Conclusions

We found a high prevalence of POCUS signs in children with TB compared with children with unlikely TB. POCUS-positivity was dependent on nutritional status but not on HIV status or age. TB-focused POCUS could potentially play a supportive role in the diagnosis of TB in children.

Trial registration number

NCT05364593.
Study protocol for the use of time series forecasting and risk analyses to investigate the effect of the COVID-19 pandemic on hospital admissions associated with new-onset disability and frailty in a national, linked electronic health data setting
Authors: Thomas Seth , Machuel Perrine , Foubert Josephine , Nafilyan Vahe , Bannister Neil , Colvin Helen , Routen Ash , Morriss Richard , Khunti Kamlesh , Farooqi Azhar , Armstrong Natalie , Gray Laura , Gordon Adam
Published: May 2023

Introduction

Older people were at particular risk of morbidity and mortality during COVID-19. Consequently, they experienced formal (externally imposed) and informal (self-imposed) periods of social isolation and quarantine. This is hypothesised to have led to physical deconditioning, new-onset disability and frailty. Disability and frailty are not routinely collated at population level but are associated with increased risk of falls and fractures, which result in hospital admissions. First, we will examine incidence of falls and fractures during COVID-19 (January 2020–March 2022), focusing on differences between incidence over time against expected rates based on historical data, to determine whether there is evidence of new-onset disability and frailty. Second, we will examine whether those with reported SARS-CoV-2 were at higher risk of falls and fractures.

Methods and analysis

This study uses the Office for National Statistics (ONS) Public Health Data Asset, a linked population-level dataset combining administrative health records with sociodemographic data of the 2011 Census and National Immunisation Management System COVID-19 vaccination data for England. Administrative hospital records will be extracted based on specific fracture-centric International Classification of Diseases-10 codes in years preceding COVID-19 (2011–2020). Historical episode frequency will be used to predict expected admissions during pandemic years using time series modelling, if COVID-19 had not occurred. Those predicted admission figures will be compared with actual admissions to assess changes in hospital admissions due to public health measures comprising the pandemic response. Hospital admissions in prepandemic years will be stratified by age and geographical characteristics and averaged, then compared with pandemic year admissions to assess more granular changes. Risk modelling will assess risk of experiencing a fall, fracture or frail fall and fracture, if they have reported a positive case of COVID-19. The combination of these techniques will provide insight into changes in hospital admissions from the COVID-19 pandemic.

Ethics and dissemination

This study has approval from the National Statistician’s Data Ethics Advisory Committee (NSDEC(20)12). Results will be made available to other researchers via academic publication and shared via the ONS website.
Protocol of a multicentre randomised controlled trial assessing transperineal prostate biopsy to reduce infectiouscomplications
Authors: Hu Jim , Zhu Alec , Vickers Andrew , Allaf Mohamad Ezzeddine , Ehdaie Behfar , Schaeffer Anthony , Pavlovich Christian , Ross Ashley E , Green David A , Wang Gerald , Ginzburg Serge , Montgomery Jeffrey S , George Arvin , Graham John N , Ristau Benjamin T , Correa Andres , Shoag Jonathan E , Kowalczyk Keith J , Zhang Tenny R , Schaeffer EM
Published: May 2023

Introduction

Approximately one million prostate biopsies are performed annually in the USA, and most are performed using a transrectal approach under local anaesthesia. The risk of postbiopsy infection is increasing due to increasing antibiotic resistance of rectal flora. Single-centre studies suggest that a clean, percutaneous transperineal approach to prostate biopsy may have a lower risk of infection. To date, there is no high-level evidence comparing transperineal versus transrectal prostate biopsy. We hypothesise that transperineal versus transrectal prostate biopsy under local anaesthesia has a significantly lower risk of infection, similar pain/discomfort levels and comparable detection of non-low-grade prostate cancer.

Methods and analysis

We will perform a multicentre, prospective randomised clinical trial to compare transperineal versus transrectal prostate biopsy for elevated prostate-specific antigen in the first biopsy, prior negative biopsy and active surveillance biopsy setting. Prostate MRI will be performed prior to biopsy, and targeted biopsy will be conducted for suspicious MRI lesions in addition to systematic biopsy (12 cores). Approximately 1700 men will be recruited and randomised in a 1:1 ratio to transperineal versus transrectal biopsy. A streamlined design to collect data and to determine trial eligibility along with the two-stage consent process will be used to facilitate subject recruitment and retention. The primary outcome is postbiopsy infection, and secondary outcomes include other adverse events (bleeding, urinary retention), pain/discomfort/anxiety and critically, detection of non-low-grade (grade group ≥2) prostate cancer.

Ethics and dissemination

The Institutional Review Board of the Biomedical Research Alliance of New York approved the research protocol (protocol number #18-02-365, approved 20 April 2020). The results of the trial will be presented at scientific conferences and published in peer-reviewed medical journals.

Trial registration number

NCT04815876.
Assessing discrepancies in estimates of road traffic deaths in Brazil
Authors: Bhalla Kavi , Job Soames , Mitra Sudeshna , Harrison James E , Mbugua Leah Watetu , Neki Kazuyuki , Gutierrez Hialy , Balasubramaniyan Ramshankar , Winer Mercer , Vos Theo , Hamilton Erin
Published: May 2023

Introduction

The First UN Decade of Action for Road Safety (2011–2020) ended with most low/middle-income countries (LMICs) failing to reduce road traffic deaths. In contrast, Brazil reported a strong decline starting in 2012. However, comparisons with global health statistical estimates suggest that official statistics from Brazil under-report traffic deaths and overestimate declines. Therefore, we sought to assess the quality of official reporting in Brazil and explain discrepancies.

Methods

We obtained national death registration data and classified deaths to road traffic deaths and partially specified causes that could include traffic deaths. We adjusted data for completeness and reattributed partially specified causes proportionately over specified causes. We compared our estimates with reported statistics and estimates from the Global Burden of Disease (GBD)-2019 study and other sources.

Results

We estimate that road traffic deaths in 2019 exceeded the official figure by 31%, similar to traffic insurance claims (27.5%) but less than GBD-2019 estimates (46%). We estimate that traffic deaths have declined by 25% since 2012, close to the decline estimated by official statistics (27%) but much more than estimated by GBD-2019 (10%). We show that GBD-2019 underestimates the extent of recent improvements because GBD models do not track the trends evident in the underlying data.

Conclusion

Brazil has made remarkable progress in reducing road traffic deaths in the last decade. A high-level evaluation of what has worked in Brazil could provide important guidance to other LMICs.
Narrative-based learning for person-centred healthcare: the Caring Stories learning framework
Authors: Mazzoli Smith Laura , Villar Feliciano , Wendel Sonja
Published: May 2023

This paper describes the learning framework for an innovative narrative-based training platform for healthcare professionals based on older patients’ narratives. The aim of Caring Stories is to place patients’ desires and needs at the heart of healthcare and by doing so to promote person-centred care (PCC). It is argued that this narrative-based approach to training in healthcare education will provide professionals from different fields with competencies to better understand how to interpret the lifeworlds of older people, as well as facilitate better communication and navigation through increasingly complex care trajectories. The spiral learning framework supports narrative-based training to be accessible to a broad range of healthcare practitioners. We suggest this is a theoretically sophisticated methodology for training diverse healthcare professionals in PCC, alongside core tenets of narrative medicine, with applicability beyond the patient group it was designed for. The learning framework takes into account professionals’ mindsets and draws on the epistemic tenets of pragmatism to support interprofessional education. Being informed by narrative pedagogy, narrative inquiry, and expansive learning and transformative learning theories, ensures that a robust pedagogical foundation underpins the learning framework. The paper sets out the conceptual ideas about narrative that we argue should be more widely understood in the broad body of work that draws on patient narratives in healthcare education, alongside the learning theories that best support this framing of narrative. We suggest that this conceptual framework has value with respect to helping to disseminate the ways in which narrative is most usefully conceptualised in healthcare education when we seek to foster routes to bring practitioners closer to the lifeworlds of their patients. This conceptual framework is therefore generic with respect to being a synthesis of the critical orientations to narrative that are important in healthcare education, then adaptable to different contexts with different patient narratives.
GA-LQR for vehicle semi-active suspension with BiLSTM inverse model of magnetic rheological damper
Authors: Chen Chong , Ma Ran , Ma Wan
Published: May 2023

This paper proposes a magnetic rheological (MR) semi-active control method based on bidirectional long short-term memory (BiLSTM) neural network, linear quadratic regulator (LQR) control algorithm, and genetic algorithm (GA). The LQR algorithm with GA optimizing the weight coefficients generates the expected damping force. Due to the nonlinear hysteresis characteristics of the magnetic rheological damper (MRD) and the fact that its input and output have certain time dependence, an inverse model of MRD is established by BiLSTM. The control current is predicted by BiLSTM and then the current is input to the MRD to obtain the damping force that is infinitely close to the expected damping force. The damping force is then applied to the suspension system to form a complete closed-loop feedback control, which realizes the damping effect and generates a real-time control. The simulation results show that the MRD inverse model can accurately predict the required control current, and the GA-optimized LQR control algorithm has a good suppression effect on the vertical vehicle acceleration, dynamic tire load, and suspension dynamic stroke.
First-principles investigation of phase stability and effects on ductility for MoSi2 alloyed by Al and Nb
Authors: Hu Hai , Wang Xu , Wang Yanbiao , Shao Qijun , Li Shaorong
Published: May 2023

In this paper, site preference, phase stability and elastic parameters of MoSi2 for Al and Nb addition are studied using first-principles calculation. The results show that alloying elements can cause MoSi2 to change from C11b to C40 phase and the phase transition is due to the activated 1/2[[Formula: see text]11](110) slip system for C11b. [Formula: see text] ratio reveals that the ductility is enhanced after phase transition. Ductile factor [Formula: see text] based on competitive processes between micro-crack opening and dislocations emission is defined to assess the ductility of MoSi2. Interestingly, the increased ductility is due to the activated dislocation emission but suppressed crack propagation. Finally, charge density and DOS indicate that the improved ductility is due to the weakened Mo-4d and Si-3p covalent interactions.
Impact of nanoparticles on speed of discharging considering homogeneous model for thermophysical features
Authors: Almohsen Bandar
Published: May 2023

Numerical unsteady approach based on Galerkin method with the inclusion of adaptive mesh was executed in this paper to simulate the freezing of water within a container. The domain has two triangular and trapezoidal cold surfaces and two adiabatic walls. The governing equations show the domination of conduction and transient source term has been involved. Galerkin method for modeling was applied and good accommodation has been reported based on comparison with previous data. Adding nano-powders makes the amount of heat to be released with stronger conduction and freezing time decreases about 26.76% when [Formula: see text]. Augmenting the fraction of powders can make the rate of process increase. For the greatest fraction of powders, an augmenting shape factor can enhance the speed of process about 6.95%.
THE ECONOMY IS NOT FLAT: THE TECHNOLOGY GRADIENT IN THE MASS MARKET ECONOMY
Authors: MAYER-FOULKES DAVID , HAFNER KURT A.
Published: May 2023

In an industrial market economy, the interaction between monopolistic and competitive sectors results in within-country productivity differences, inequality and inefficiency. We demonstrate this using a two-sector mass market economy model. The monopolistic sector represents large-scale, mass production and is associated with innovation and market power, while the competitive sector represents small-scale production and engages instead in technological absorption. The endogenous dynamics of technological change between the two sectors generate a steady state technology gradient, with the competitive sector lagging behind. This technology gradient is a key endogenous feature of the industrial market economy, associated with economic growth, that generates inequality and inefficiency. Inequality is generated in two ways: innovation profits are concentrated among a few owners of large-scale innovation, while economy-wide wage levels reflect the lagging small-scale technological level. The model shows there are innovative-distributive policies that can increase efficiency in production, innovation, and absorption, and restore income equality, increasing wages and reducing profits. A cointegration and weak exogeneity panel study of the US states between 1997 and 2011 corroborates that the large-scale sector drives aggregate employment, wages and inequality, while top income inequality makes the technology gradient steeper.
An introduction to the chalk aquifers of northern Europe
Authors: West L. J. , Farrell R. P. , Foley A. E. , Howlett P. R. , Massei N.
Published: May 2023

We briefly outline the progressive development of approaches to both the characterization and simulation of the hydrogeology of northern European chalk aquifers, which were some of the first in the world to be studied. The volume's scope includes work on water resources and quality, chalk streams and wetland ecosystems, chalks as heat reservoirs for building temperature regulation, sources of groundwater flood risk and impacts of engineering on the subsurface, and diffuse and point-source pollution affecting these aquifers. It excludes hydrocarbon-related studies and those focused on offshore chalk sequences. We briefly outline the current state of knowledge of hydrogeological processes, characterization, assessment and modelling, and the increasingly recognized importance of karst features. The latter were little discussed 20 years ago and are still often neglected. There follows a brief quantitative analysis of publication topics relating to chalk hydrogeology in the scientific literature over the past three decades, which highlights key trends including both the purposes of studies and the methods employed. We present a summary of the topics and contributions within this volume, and conclude by identifying the key issues that need to be addressed in order to ensure the sustainability of our chalk aquifers for the future.
Experimental insight into basaltic andesite lava dome oxidation textures at La Soufrière, St Vincent
Authors: Morrison-Evans Beitris , Melekhova Elena , Blundy Jonathan
Published: May 2023

Petrological analysis of the 2020–21 La Soufrière lava dome reveals ubiquitous oxidation textures. Comparison of the natural dome rock to subsequent explosive scoria phases highlights the lack of any oxidation features in the latter, indicating that oxidation processes affected only the dome-forming magma, either during pre-eruptive storage or upon emplacement. To investigate the causes of oxidation we present a series of one-atmosphere experiments, using fresh natural basaltic andesite scoria as a starting material. Experiments were performed at 900 and 1020°C and at oxygen fugacities between NNO − 2 and air. Experimental results show that iron oxide nanolites nucleate on the rims of pyroxene microlites and phenocrysts under all experimental conditions except at NNO − 2. Orthopyroxene phenocrysts become unstable at 1020°C, at and above NNO + 2. Olivine symplectites form in all experiments at and above NNO. Titanomagnetite co-exsolves titanohematite and an Mg–Fe–Al spinel (pleonaste–magnesioferrite) at and above NNO + 2. Well-developed Mg–Fe–Al spinel trellis exsolution lamellae in titanomagnetite phenocrysts, as seen in the dome, only form in the presence of air at 900°C. The combination of textures and compositions observed in the natural dome indicates that oxidation of the dome magma occurred during emplacement at Earth's surface, with air percolating through the dome at temperatures ≤900°C.
Toward the Generation of Test Vectors for the Detection of Hardware Trojan Targeting Effective Switching Activity
Authors: Mondal Anindan , Kalita Debasish , Ghosh Archisman , Roy Suchismita , Sen Bibhash
Published: May 2023

Hardware Trojans (HTs) are small circuits intentionally designed by an adversary for harmful purposes. These types of circuits are extremely difficult to detect. An HT often requires some specific signals to activate, which are almost impossible to discover. For this reason, test generation for side-channel analysis has gained significant attention in recent times and does not require HT activation. Such test generation techniques aim to generate a large amount of switching activity inside the HT circuit, increasing transient current measurement. However, such methods suffer from either long runtime or reliable results. In this work, a test generation technique is proposed based on the relative switching activity of the circuit to overcome the limitations of the existing works. Initially, the proposed technique measures the impact of each input on rare nets individually using random vector simulation. Potent inputs are selected to obtain a new set of test vectors that provide high relative switching inside a circuit. The proposed method is applied on 11 different ISCAS and 3 ITC 99 benchmark circuits. Experimental results endorse the efficacy of the proposed method outperforming traditional Hamming distance-based re-ordering techniques (up to 20×) while requiring a small runtime.
(Invited, Digital Presentation) Low-Temperature Direct Bonding of Wide-Bandgap Semiconductor Substrates
Authors: Matsumae Takashi , Umezawa Hitoshi , Kurashima Yuichi , Takagi Hideki
Published: May 2023

For the next-generation semiconductor devices, our research group has developed direct bonding techniques of wide-bandgap materials, including SiC, Ga2O3, and diamond. It is known that the semiconductor substrates activated by oxygen plasma can form atomic bonds at low temperatures. In this case, a thick oxide layer, which may become a thermal and electrical barrier, is formed at the bonding interface. Meanwhile, our research group demonstrated that the OH-terminated Ga2O3 and diamond substrates were directly bonded without an oxide intermediate layer. In addition, the SiC substrate dipped into the HF acid can be bonded with the Ga2O3 substrate with an ~1-nm-thick amorphous layer. The dissimilar substrates bonded through the ultra-thin intermediate layer would contribute to efficient heat dissipation and future heterojunction devices.
(Invited) Non-Enzymatic Glucose Sensor Fabricated By Ni-Nanowires Decorated Graphene Gated FETs
Authors: Hung Sheng-Chun , Chen Chia-Chi , Lin Yu-Cheng , Lin Chung-Wei
Published: May 2023

In this study, an innovative non-invasive glucose sensor made of nickel nanowire-decorated graphene-gated field-effect transistors is demonstrated. Due to the redox reaction between nickel nanowires and glucose molecules, electron exchange occurs when Ni(III) reacts with glucose to form Ni(II) and gluconolactone. Changes in electron concentration are amplified by transistors at the bottom, improving detection sensitivity. In this study, the electrical properties of glucose sensor fabricated from nickel nanowire/graphene/gold surfaces was studied. Since the CVD-grown graphene film has excellent electrical conductivity, the electrons generated by the redox reaction can be quickly and evenly dispersed. The results show that the glucose sensor with graphene film has good current stability, low detection limit and good linear relationship between current and concentration. The demonstrated nickel wire-decorated graphene-gated FET biosensor can be used for the quantification of glucose with a linear range of 10-50 mM and a detection limit of 51nM.
Green Hydrogen via PEM Electrolysis – Avoiding Iridium Supply Limitations
Authors: Clapp Mark , Zalitis Christopher Mark , Ryan Margery
Published: May 2023

The reliance of proton exchange membrane water electrolysis (PEMWE) on iridium as an oxygen evolution catalyst has led to uncertainty over whether a large-scale PEMWE industry can be realised. The future PEMWE capacity growth that is sustainable in terms of iridium supply is investigated. It is found that, if optimistic improvements in iridium utilisation and high recycling rates are achieved, a global capacity of 1.3 TW could be reached by 2050, which is above the Net-Zero Emissions 2050 target, using only 20% of annual primary iridium supply. The different catalyst strategies that can improve iridium utilisation are compared using membrane electrode assembly (MEA) testing data from the literature, with the order found to be supported nanoparticles ≈ extended surface structures > mixed oxides > nanoparticles. As a main result, it is found that a terrawatt-scale PEMWE industry can avoid being constrained by iridium supply if technological development of a similar level to that seen in PEM fuel cells is realised.
Fe and Zn Addition Effects of Ti Oxide-Based Electrocatalyst on Catalytic Activity for Oxygen Reduction Reaction
Authors: Matsuzawa Koichi , Obata Momo , Takeuchi Yuu , Ohgi Yoshiro , Nagai Takaaki , Monden Ryuji , Ishihara Akimitsu
Published: May 2023

In order to enhance the catalytic activity of non-precious oxide-based electrocatalyst for the oxygen evolution reaction (ORR), we have investigated the addition effects of Zn and Fe for Ti oxide-based electrocatalyst (TiOx) on the catalytic activity for the ORR. The Fe and Zn added TiOx (Fe,Zn-TiOx) was obviously the highest activity for the ORR, and it was higher ORR activity than Fe added TiOx (Fe-TiOx), Zn added TiOx (Zn-TiOx), and TiOx without addition. It reveals that the addition of Fe and Zn was found to be effective for enhancing the ORR activity, and Fe addition was more effective than Zn addition for enhancing the ORR activity on TiOx. As a result, it is suggested that Zn addition affected to increased electrochemical surface area of TiOx, and Fe addition affected to form active site in TiOx as similar case as Zr oxide-based electrocatalyst.
Development of Carbon-Based Integrated Electrode (GDL + Catalyst Layer) Using the Electrospinning Deposition Method
Authors: Asif Raad , Okuma Satoshi , Nagayama Mayumi , Sasaki Kazunari , Hayashi Akari
Published: May 2023

For further progress in the decarbonization of the automobile industry, accommodating the PEFC to heavy-duty vehicles is essential. This requires improved performance under high current density. One of the approaches for this is reducing the thickness of the GDL. However, simply reducing the thickness sacrifices mechanical durability. Therefore, in this study, a novel approach of combining the catalyst layer and GDL into one integrated electrode is considered. Two models of integrated electrodes, with the commercial GDL and electrospun GDL, are developed. The integrated electrode with the commercial GDL showed primitive IV performance when it was assembled to a MEA, even though only limited utilization of Pt nanoparticles was recognized. For the integrated electrode with the electrospun GDL, Pt nanoparticles were not successfully deposited, but the resulting MEA demonstrated reduced concentration overvoltage owing to the thinner electrospun GDL.
(Digital Presentation) The Utilization of Platinum Catalysts Deposited on Carbon Support Synthesized from Coffee Grounds in a Polymer Electrolyte Membrane Fuel Cell
Authors: Simson Sander , Nerut Jaak , Härmas Meelis , Valk Peeter , Teppor Patrick , Palm Rasmus , Koppel Miriam , Aruväli Jaan , Korjus Ove , Volobujeva Olga , Månsson Martin , Lust Enn
Published: May 2023

In this study, carbon support material, derived from coffee grounds was used in the preparation of Pt catalysts for polymer electrolyte membrane fuel cell (PEMFC) application. The carbon material was synthesized using ZnCl2 activated pyrolysis method and the Pt nanoparticles were deposited onto carbon support by two methods: using ethylene glycol or hydrogen as a reducing agent. Synthesis of the catalyst materials on coffee ground derived carbon was successful and produced materials with desirable physical and electrochemical properties. Synthesis through the ethylene glycol reduction method, with catalyst material deposited on the gas diffusion layers and additional Nafion layers, produced the most catalytically active material with an electrochemically active surface area value of 63 mPt
2 gPt
−1 and catalytic performance of: current density was 0.56 A cm−2 at 700 mV and maximum power density was 0.56 W cm−2. Methods of boosting PEMFC performance through deposition of catalyst material and adding additional Nafion layers were effective and assisted in increasing the overall PEMFC performance.
Electrical Conductivity and Electrochemical Performance of Pr Doped Ceria
Authors: Dubey Pawan Kumar Kumar , Hong Junsung , Lee Kevin X , Belko Seraphim , Aphale Ashish , Rahman Muhammad Anisur , Reisert Michael , Singh Prabhakar
Published: May 2023

PCO (Praseodymium Cerium Oxide) solid solution (0-50% PrOx) has been prepared by the conventional solid-state ceramic processing route using CeO2 and PrOx powders in the desired stoichiometry and sintering at 1500°C in air. Synthesized powder has been characterized for phase chemistry and lattice structure. Electrochemical characteristics of the synthesized powder has been examined using electrochemical impedance spectroscopy. The observed increase in the electrical conductivity of PCO are associated with increased concentration of oxygen vacancies created by the replacement of Ce4+ ions with Pr+3 ions. The addition of PrOx also lowered the polarization and ohmic losses.
Carbon Deposition Mechanisms on Ni-Based Anode for SOFC: A Comparison Between Non-Discharge and Discharge Modes
Authors: Muto Seina , Uno Ryuji , Watanabe Hirotatsu
Published: May 2023

Carbon deposition mechanisms were studied in Ni-based electrode in non-discharge and discharge modes. A Ni/XSZ pellet(dopant X=Y, Sc) and an anode support cell were used in a thermobalance experiment showed that operating temperature changed carbon tolerance in electrode. The Ni/ScSZ was superior to the Ni/YSZ in carbon deposition at 1173K. Meanwhile, the trend was opposite at 973K. Especially, notable difference was found at S/C(Steam-to-Carbon) ratio = 0.15. Carbon was feromed in Ni/YSZ, wherease carbon deposition was progressed in Ni/ScSZ at S/C=0.15 at 973K. It was shown that electrolyte dopant was a key to enhance carbon tolerance in the electrode. Anode support cell achieved high I-V performance when using H2, whereas that was decreased in CH4/H2O/Ar. Less carbon was found in the Ni/XSZ cermet after discharge mode.
Development Progress of a 70% Efficient Hybrid SOFC-I.C. Engine Hybrid System for Stationary Applications up to 1 MW
Authors: Braun Rob J , Floerchinger Gus , Sullivan Neal P. , Vincent Tyrone , Danforth Robert , Bandhauer Todd , Garland Shane , Olsen Daniel
Published: May 2023

Flexible and dispatchable, high-efficiency power generation supplied with carbon-neutral renewable fuels is needed to help enable defossilization of the electric grid. Pressurized, hybrid SOFC systems fueled with hydrogen, biogas, or renewable natural gas can generate clean power at ultra-high efficiency. In this summary, we provide an update on the development progress of a full-scale, hybrid system that targets low cost (<1000 $/kW) and ultra-high efficiency (70%-LHV) distributed power generation for applications up to 1 MW. The system features pressurized, metal-supported SOFC technology from Ceres Power which is integrated with a modified diesel engine which converts the residual chemical exergy in the anode tail-gas from the SOFC to drive auxiliaries and produce net additional power. Updates on critical hardware advancements around pressurized multi-stack, 30 kW fuel cell modules, low-speed high efficiency rotating equipment, and ultra-high efficiency power electronics are provided. A techno-economic outlook for such power generation systems in various stationary applications.
Development of Novel 3D Cell Structure and Manufacturing Processes for Highly Efficient, Durable, and Redox Resistant Solid Oxide Electrolysis Cells
Authors: Lee Sanghoon , Lin Haichen , Kahn Bruce E. , Malakhov Arkady , Kovach Bobby , Tran Quang Tuyen , Ghosh Sam , Liu Ping , Cormier Denis , Minh Nguyen Q.
Published: May 2023

A novel cell design and its corresponding manufacturing processes are being evaluated to demonstrate a highly efficient, durable, and reduction-oxidation (redox) resistant solid oxide electrolysis cell (SOEC) technology for hydrogen production. The cell design includes a unique 3D hydrogen electrode configuration composed of two layers ‒ a 3D hydrogen electrode support layer (for improved cell redox resistance) and an exsolved perovskite hydrogen electrode active layer (for enhanced cell performance and increased durability). The hydrogen electrode support layer consists of specifically designed 3D networks of electrode materials; tetragonal zirconia (TZ) and Ni-yttria stabilized zirconia (YSZ). Each phase is topologically connected throughout the electrode with controlled geometry and connectivity. The TZ component plays a role as an outer frame to provide structural support, while the Ni-YSZ component inside the TZ frame imparts electrical conductivity for the hydrogen electrode support layer. The hydrogen electrode active layer, which primarily supports electrochemical reaction, is a nickel-substituted perovskite that will exsolve nickel nanoparticles on the oxide surface when exposed to a reducing environment and is redox-reversible. A fabrication scheme being developed for this cell design incorporates a printing-based additive manufacturing (AM) process for producing the 3D hydrogen electrode. This paper presents the progress to date in developing the printing fabrication process for the 3D hydrogen electrode support and evaluating exsolved nickel-substituted perovskite for the hydrogen electrode active layer.
Modeling of a Single Repeating Unit for Protonic Ceramic Cell Applications
Authors: Ferrero Domenico , Dealberti Gabriele , Anelli Simone , Baggio Andrea , Schmider Daniel , Dailly Julian , Smeacetto Federico , Santarelli Massimo
Published: May 2023

Protonic Ceramic Cells (PCCs) are a promising alternative to oxygen-ion conducting solid oxide cells (SOCs), offering benefits for hydrogen separation, electrolysis and fuel cell applications. The current development stage is focusing on the scale-up of the technology to cross the gap between single cells and stacks. The design of single repeating units (SRU) is the intermediate stage of the development. This work developed a numerical model for the 3D steady-state simulations of an SRU geometry designed for a circular, anode-supported PCC. The model has been applied to the simulation of fuel cell operation and has been calibrated using experimental data from the literature. The model is able to accurately reproduce experimental results obtained at 600 °C. The simulation platform developed can be also adapted to the simulation of electrolysis operation and can be applied to the optimization of the SRU geometry.
Total Energy for the SOFC and SOEC
Authors: Williams Mark , Gemmen Randall
Published: May 2023

The Solid Oxide Fuel Cell (SOFC) Program at the National Energy Technology Laboratory (NETL) managed by the U.S. Department of Energy (DOE) Office of Fossil Energy and Carbon Management (FECM) is currently developing low-cost SOFC and Solid Oxide Electrolysis Cell (SOEC) systems. This paper develops the Total Energy (TE) (kilowatt-hours per kilogram hydrogen, kWh/kgH2 ) for the SOEC and SOFC. The Total Energy includes heat input, exergetic flows, enthalpy of vaporization, pressurization, heat loss, area specific resistance, etc. The SOEC Total Energy developed at NETL, as it would happen, correlates well with the Idaho National Laboratory (INL) proven SOEC performance of forty-five kilowatt-hours per kilogram hydrogen at twenty bars, 1.3 volt and 725oC. Total Energy is necessary for designing, predicting, and planning for SOEC and SOFC performance and cost.
Inhibiting in Situ Phase Transition in Ruddlesdenpopper Perovskite Via Tailoring Bond Hybridization for Oxygen Ion Conduction
Authors: Han Ning , Zhang Xuan , Guo Xiangyu , Liu Shaomin , Fransaer Jan
Published: May 2023

Owing to the excellent physical and chemical properties, mixed ionic-electronic conducting oxides, especially Ruddlesden-Popper (RP)perovskite oxides, are interesting materials for environment and energy research. Phase transition is a common phenomenon for these materials, which generally exerts a great influence on the properties and functionalities. Element-doping has been recognized as a facile and efficient strategy to improve the oxygen ionic or electronic conductivity or to stabilize the crystal phase structure. However, in-depth understanding of the mechanism of phase transition is still limited so far. Herein, we try to reveal the mechanism of molybdenum substitution in B-site of RP perovskite (Pr2NiO4) to induce the ex-situ collapse and to inhibit the in-situ phase transition. This work not only provides a thorough explanation of the phase transition process based on element doping but also presents a novel high-performance oxygen permeation membrane.
Direct Ammonia-Fed Liquid Metal Anode Solid Oxide Fuel Cell for Co-Generation of Hydrogen and Electricity
Authors: Zhou Fangzhe , Jiang Yidong , Gu Xin , Shi Yixiang , Cai Ningsheng
Published: May 2023

Ammonia shows great promise as a carbon-free alternative fuel with high hydrogen content, nice energy density and developed supply chain. For solid oxide fuel cells (SOFCs), ammonia decomposition at the anode forms a high temperature gradient, thus exerting a negative effect on the cell durability. In this research, a liquid antimony anode (LAA) SOFC was prepared as an electrochemical partial oxidation reformer. Part of ammonia was electrochemically oxidized at the LAA for producing heat and electricity, while the rest was decomposed to H2 and N2. The single cell exhibited a current density of 128 mA/cm2 at 0.4V and 850℃. Thermodynamic calculations showed that the heat release can be balanced with the heat adsorption. LAAs with high thermal conductivity transferred ammonia oxidation heat and prevented a high temperature gradient. This work showed the potential of LAA-SOFCs for co-generation of hydrogen and electricity from ammonia.
Towards an Impedance-Based Analysis of SOFC-Stacks
Authors: Golani Sadhana , Bausinger Holger , Mai Andreas , Weber Andre
Published: May 2023

This proceeding aims to understand the performance of SOFC stacks using impedance spectroscopy. For the stack analysis, gradients over the active cell area are averaged out, preventing access to local phenomena. Hence, to get better insight into the spatial distribution of losses, single cells with an active electrode area of 1 cm² are characterized at 850 °C based on EIS and DRT-analysis. To ensure an appropriate deconvolution of processes, symmetrical anode and cathode cells are also tested. Next to the ideally contacted cells, metallic interconnecting repeat units are analyzed to study the impact of contacting and gas supply in the stack. The effect of fuel utilization was also investigated by mimicking different locations in the stack. In this contribution, the complex impedance behavior of the stack based on polarization losses will be discussed. The paper also provides disentangled information often lost or averaged out in stacks.
Electrochemical Activity and Stability of Pure Gadolinium Doped Ceria as Fuel Electrode in Solid Oxide Electrolysis Cells
Authors: Uecker Jan , Unachukwu Ifeanyichukwu Daniel , Vibhu Vaibhav , Vinke Izaak , Eichel Rudiger-A , de Haart L.G.J. (Bert)
Published: May 2023

The utilization of novel fuel electrode materials could be a valid solution to improve the durability of solid oxide electrolysis cells and the path way for worldwide commercialization. Especially, Ni-free fuel electrodes are promising to eliminate Ni migration as an important degradation mechanism. Gadolinium doped ceria (GDC) is an interesting material due to its good stability towards carbon deposition and the possibility to host electrocatalysis in electrolysis conditions. The present study aims to investigate the performance, electrochemical processes and long-term stability of pure GDC fuel electrode single cells. The results show a lower degradation rate in comparison to similar produced Ni-GDC single cells in steam electrolysis conditions and around 70 % of its performance. Furthermore, the charge transfer in the GDC fuel electrode is identified as the reaction rate-determining process in the GDC fuel electrode single cells.
Ni / GDC Fuel Electrode for Low Temperature SOFC and its Aging Behavior under Accelerated Stress
Authors: Liu Yanting , Juckel Martin , Menzler Norbert H. , Weber Andre
Published: May 2023

The microstructural integrity of Ni-based fuel electrodes is mandatory for long term SOFC operation. Degradation due to microstructural changes as Ni-agglomeration, sintering and densification has to be prevented by an appropriate microstructure. In this work the performance of 4 types of nickel-ceria based fuel electrodes, which differ with respect to layer sequence and manufacturing processes, is evaluated by electrochemical impedance spectroscopy at the nominal operating temperature of 600 °C. Accelerated degradation tests at increased operating temperatures of 700 °C and 900 °C are performed on the one based on a GDC infiltrated Ni-backbone that performed the best. The polarization resistance at 600 °C recorded at the beginning and the end of life increased by up to 100%. Microstructural analysis of the electrodes at different aging states revealed strong microstructural changes of fine infiltrated GDC structures and Ni agglomeration at higher operating temperature.
Additive Manufacturing of Single-Layer Protonic Ceramic Fuel Cells
Authors: Asghar Muhammad Imran , Lund Peter D.
Published: May 2023

Single-layer proton conducting ceramic fuel cells (PCFCs) were fabricated through a hybrid of extrusion-based 3D printing utilizing BaZr0.4Ce0.4Y0.1Yb0.1O3-δ (BZCYYb) as an ionic conductor, and BaCo0.4Fe0.4Zr0.1Y0.1O3-δ (BCFZY) as the electrode material. The rheological properties of the printable pastes were investigated in detail. The 3D printed single-layer cell produced a maximum power density of 283 mW/cm2 at 550oC. The performance was mainly limited due to limited surface area on both sides of the cell. The performance improved by 17% (331 mW/cm2) when porous layers were added on both sides of the cell. In addition, cells with traditional 3-layer structure were fabricated using NiO-BZCYYb as anode, BZCYYb as electrolyte, and BCFZY-BZCYYb as cathode. The cell produced a maximum power density of 426 mW/cm2 at 650OC. The performance improved by 120% (938 mW/cm2) when a composite of BZCYYb and a eutectic mixture of Li2CO3, Na2CO3 and K2CO3 was used as electrolyte.
Computational and Experimental Study on the Combined Sulfur and Chromium Poisoning Mechanism of LSM, LSCF and LNO Cathodes
Authors: Wang Rui , Parent Lucas R , Gopalan Srikanth , Zhong Yu
Published: May 2023

Perovskites (La,Sr)MnO3 (LSM) and (La,Sr)(Co,Fe)O3 (LSCF) phases and Ruddlesden-Popper phase La2NiO4 (LNO) as solid oxide fuel cell (SOFC) cathodes, have been used due to its high efficiency and low emissions. To further understand the long-term degradation mechanism of the LSM, LSCF, and LNO phase in SO2 and Cr vapor gas impurities, they were prepared, sintered, and heat-treated at 800, 900, and 1000 ℃ in the sulfur, chromium, and water vapor-containing atmospheres, respectively. Later, XRD, SEM, and TEM techniques were applied to the samples, and corresponding simulations were made by the CALPHAD approach based on the same experimental conditions to verify the formation of the detrimental secondary phases. Results showed good agreement among the predictions and experiments. More importantly, extensive simulations were conducted under different conditions (temperature, the partial pressure of oxygen, and impurities) to understand the long-term degradation mechanism and optimize the operating conditions.
Cardiomyocyte nuclear remodeling after mechanical unloading
Authors: Luo Jun , Farris Stephen D. , Helterline Deri , Stempien-Otero April
Published: May 2023

Our data suggest that increases in DNA content that occur with cardiomyocyte hypertrophy in heart failure may reverse with mechanical unloading.
Altered contractility, Ca2+ transients, and cell morphology seen in a patient-specific iPSC-CM model of Ebstein’s anomaly with left ventricular noncompaction
Authors: Thareja Suma K. , Anfinson Melissa , Cavanaugh Matthew , Kim Min-Su , Lamberton Peter , Radandt Jackson , Brown Ryan , Liang Huan-Ling , Stamm Karl , Afzal Muhammad Zeeshan , Strande Jennifer , Frommelt Michele A. , Lough John W. , Fitts Robert H. , Mitchell Michael E. , Tomita-Mitchell Aoy
Published: May 2023

We demonstrate here that iPSCs derived from patients with Ebstein’s anomaly and left ventricular noncompaction, when differentiated into cardiomyocytes, display significant structural and functional changes that offer insight into disease pathogenesis, including altered ER/SR and mitochondrial morphology, contractility, and calcium signaling.
Connected ϵ‐Chainable Sets and Existence Results
Authors: Bhandari Samir Kumar , Chandok Sumit , Jana Bishnupada , Das Radha Binod
Published: May 2023

In the setting of ϵ‐chainable metric spaces, we introduce (ϵ − ρ − σ) uniformly local weak contraction and obtain some results on the existence of fixed points. To show the veracity of the results, we also constructed some examples.
Numerical Study of the Influence of the Spatial Distribution of Oversized Rock Blocks on the Stability of Soil-Rock Mixture Slopes
Authors: Gao Wenwei , Yang Hairong , Teng JinBiao , Sun Yongshuai
Published: May 2023

Soil-rock mixtures (S-RMs), as special engineering geological materials, are widely distributed in mountainous regions and are important hosts of slope disasters. Stability studies are very important for predicting S-RM slope safety during the construction and operation of engineering projects. To investigate S-RM slope stability considering the spatial distribution of oversized rock blocks in the slope, the distinct element method (DEM) program particle flow code in two dimensions (PFC2D) was used to analyse the stability of slopes composed of S-RMs. First, according to the stochastic approach, different numerical models of an S-RM slope were established with different oversized rock block spatial distributions. Then, the S-RM slope models were simulated, the safety factor and sliding characteristics of the slopes were analysed, and the unbalanced contact force and rotational characteristics of the oversized rock blocks were discussed. Finally, the concept of key rock blocks in S-RM slopes was proposed, and their spatial distribution characteristics and influence characteristics were summarized. The findings of this study suggest that oversized rock blocks have a certain influence on the stability of S-RM slopes.