bluuebunny/crossref_metadata_2025 huggingface dataset:
Risk factors for poorer respiratory outcomes in adolescents and young adults born preterm
Authors: Smith Elizabeth F , Hemy Naomi R , Hall Graham L , Wilson Andrew C , Murray Conor P , Simpson Shannon J
Published: May 2023

Rationale

The respiratory outcomes for adult survivors of preterm birth in the postsurfactant era are wide-ranging with prognostic factors, especially those encountered after the neonatal period, poorly understood.

Objectives

To obtain comprehensive ‘peak’ lung health data from survivors of very preterm birth and identify neonatal and life-course risk factors for poorer respiratory outcomes in adulthood.

Methods

127 participants born ≤32 weeks gestation (64%, n=81 with bronchopulmonary dysplasia (BPD), initially recruited according to a 2 with-BPD:1 without-BPD strategy), and 41 term-born controls completed a lung health assessment at 16–23 years, including lung function, imaging and symptom review. Risk factors assessed against poor lung health included neonatal treatments, respiratory hospitalisation in childhood, atopy and tobacco smoke exposure.

Measurements and main results

Young adults born prematurely had greater airflow obstruction, gas trapping and ventilation inhomogeneity, in addition to abnormalities in gas transfer and respiratory mechanics, compared with term. Beyond lung function, we observed greater structural abnormalities, respiratory symptoms and inhaled medication use. A previous respiratory admission was associated with airway obstruction; mean forced expiratory volume in 1 s/forced vital capacity z-score was −0.561 lower after neonatal confounders were accounted for (95% CI −0.998 to –0.125; p=0.012). Similarly, respiratory symptom burden was increased in the preterm group with a respiratory admission, as was peribronchial thickening (6% vs 23%, p=0.010) and bronchodilator responsiveness (17% vs 35%, p=0.025). Atopy, maternal asthma and tobacco smoke exposure did not influence lung function or structure at 16–23 years in our preterm cohort.

Conclusions

Even after accounting for the neonatal course, a respiratory admission during childhood remained significantly associated with reduced peak lung function in the preterm-born cohort, with the largest difference seen in those with BPD. A respiratory admission during childhood should, therefore, be considered a risk factor for long-term respiratory morbidity in those born preterm, especially for individuals with BPD.
Dynamical characterization of the wave’s propagation of optical pulses in monomode fibers
Authors: Khater Mostafa M. A.
Published: May 2023

This study investigates some novel solitary wave solutions of the perturbed Chen–Lee–Liu ([Formula: see text]) equation to explain the physical and dynamic behavior of the pulse in optical fiber. The perturbed [Formula: see text] equation is one of the icon models that have been derived from the well-known Schrödinger equation. Two analytical techniques are used to obtain novel solitary wave solutions. Then, using a well-known numerical scheme, these solutions are looked at objectively to figure out why they work. Several graphs in different styles are used to show how the pulse waves in an optical fiber are analyzed and how accurate the analysis is. The scientific novelty of this research is given by explaining the comparison figure out of our results that have been published in some recently published research papers.
Effects of plasma treatments on the surface wettability properties of PTFE polymeric films
Authors: Al-Yousef Haifa A. , Atta A. , Abdeltwab E. , Atta M.R , Abdel-Hamid M. M.
Published: May 2023

A cold cathode plasma source is constructed for modifying PTFE surface characteristics. The source was easily built, had a consistent plasma discharge medium and acceleration system. A cylindrical Langmuir probe is also used to evaluate plasma parameters like density, temperature or even plasma potential. This probe is designed to be moveable so that it may approach any desired position in the plasma volume. The influences of nitrogen pressure and probe-cathode gap on plasma parameters were investigated. The electron temperature [Formula: see text] fluctuated from [Formula: see text] to [Formula: see text][Formula: see text]eV as the pressure rises from 0.2 to 0.4[Formula: see text]mbar. Further, by increasing the cathode-probe gap from 0.4 to 2[Formula: see text]cm, the electron densities increased from [Formula: see text][Formula: see text]cm[Formula: see text] to [Formula: see text][Formula: see text]cm[Formula: see text]. Furthermore, the contact angles, work of adhesion and surface free-energy of pristine as well as irradiated PTFE films, were estimated. The results demonstrated that by extending the plasma exposure duration from 0 to 12[Formula: see text]min, the water contact angle is lowered from 82.2∘ to 30.5∘. At these conditions, the work of adhesion is raised from 81.9 to 134.1[Formula: see text]mJ/m2, as the surface free energy is increased from 29.8 to 71.8[Formula: see text]mJ/m2.
Numerical modeling based on the analytical solution of the steady-state small signal photocarrier grating equations and analysis of field-dependent measurements for noncrystalline Si: H samples
Authors: Badran R. I.
Published: May 2023

The available experimental data of field-dependent steady-state photocarrier grating (SSPG) are numerically modeled employing the derived formula of [Formula: see text] (where [Formula: see text] represents the ratio of coherent to incoherent currents in SSPG technique) obtained from the analytical solution of the small signal steady-state grating problem by applying Galerkin’s method. This numerical analysis shows the extent of validity and success of using the derived formula of [Formula: see text] [R. I. Badran, Results Phys. 17, 103079 (2020)] in reproducing the field-dependent data for noncrystalline Si: H samples. The best quality of fittings is reproduced when [Formula: see text] value is minimum. This analysis provides us with approximate and corrected values for each of transport quantities, namely, the small-signal response lifetime, electron and hole mobilities that are found in agreement with the values obtained from the applications of other methods. For two polymorphous (pm) Si: H samples, the average estimated, corrected values for the carrier density and mobility-lifetime product, namely, [Formula: see text][Formula: see text]cm[Formula: see text] and [Formula: see text][Formula: see text]cm[Formula: see text] and ([Formula: see text][Formula: see text]cm2V[Formula: see text] and [Formula: see text][Formula: see text]cm2V[Formula: see text], respectively, are obtained. The analysis is also extended to analyze the field-dependent data for nanocrystalline (nc) Si: H samples at low temperatures. The extracted values of [Formula: see text] and ([Formula: see text] are [Formula: see text][Formula: see text]cm[Formula: see text] and [Formula: see text][Formula: see text]cm2V[Formula: see text].
Multiparty-controlled remote state preparation of multiple qubit-string information
Authors: Peng Jia-Yin , Xiang Yi
Published: May 2023

In this paper, we first propose a remote state preparation (RSP) scheme in the traditional sense, which accomplishes the remote preparation of a single-qubit controlled by multiple agents in the network. This triggers a new RSP scheme, by which we can remotely prepare tensor product-type quantum states controlled by one agent. After that, we generalize the above approach to the RSP scheme of multi-qubit information controlled by multiple agents in the network. In the extended scheme, as long as all agents operate faithfully, the receiver can recover all qubits of information in the original state; otherwise, the scheme fails. Such a scheme entangles quantum information in the preparation process, thus slashing the cost of such quantum resources as auxiliary qubits and local unitary operations, and, meanwhile, reducing the number of classical bits transferred among participants. Finally, we further investigate the remote preparation scheme for multiple qubit-string information under the control of multiple agents in the network.
The relationship between sleep quality and gait in people with multiple sclerosis: A pilot study
Authors: Abedalaziz Wlla , Al-Sharman Alham , Aburub Aseel , Latrous Mariem Syrine , Esser Patrick , Dawes Helen , El-Salem Khalid , Khalil Hanan
Published: May 2023

Background: Gait deficits are common among people with multiple sclerosis (PwMS). Therefore, investigating factors that may influence walking in PwMS is important. Previous studies in older adults and other neurological populations demonstrated the relationship between sleep quality and gait performance. Despite the fact that the prevalence of poor sleep quality is very high among PwMS, little is known about the effect of sleep quality on gait among PwMS.

Objective: This study aimed to explore the relationship between sleep quality and gait performance in PwMS.

Methods: Forty-one PwMS participated in the study between February 2019 and December 2019. Participants were asked to walk at a self-selected speed over 10[Formula: see text]m with an inertial measurement unit (IMU) attached over the back. Walking speed, step length (left and right), and step time were calculated. Sleep was estimated objectively using a wrist-worn triaxle-accelerometer; the derived parameters were sleep efficiency (SE) and the number of awakening after sleep onset (NASO).

Results: SE significantly correlated with step length ([Formula: see text]). Furthermore, the NASO significantly correlated with gait speed ([Formula: see text]), and step-time ([Formula: see text]). These correlations remained significant even after adjusting for age and disease duration.

Conclusion: We observed that when corrected for disease duration and age there were relationships between NASO and SE to gait parameters; these observations warrant further investigations.
Global geological mapping of Venus and the twenty-first-century legacy of William Smith: identification of challenges and opportunities for future research and exploration
Authors: Head James W. , Ivanov Mikhail A. , Basilevsky Alexander T.
Published: May 2023

Geological mapping principles have been applied across planet Earth since William Smith's initial 1815 map. During the Space Age, these principles were applied to smaller moons and planets, appropriately adjusted for remote conditions and data, and revealing ‘one plate planets’ recording Earth's missing chapters. Yet what of Venus, Earth's ‘twin’, shrouded in opaque clouds? How can these geological mapping principles be applied to address fundamental questions of planetary history? We outline how Venus's geological mapping over the last 35 years has proceeded towards a successively integrated more global picture that has revealed a surface and history unlike Earth or the smaller planetary bodies! The current 1 : 10 M global geological map documents geological units that all formed in the last
c.
20% of Venus's history. The oldest, Fortunian, involved intense deformation and building of thicker crust (tessera). The Guineverian featured near-global emplacement of vast volcanic plains. The Atlian saw prominent rift zones and large shield volcanoes. The three major phases of activity provide a basis for assessing the geological, atmospheric and geodynamical processes operating earlier in Venus's history that led to the preserved record, raising a series of questions to be investigated in the coming decade by an international armada of Venus missions.
Role of Proportion of Surrounding Gate on the Improved Transient Behavior of MIS Tunnel Diode with Ultra-Thin Metal Surrounded Gate (UTMSG)
Authors: Huang Sung-Wei , Hwu Jenn-Gwo
Published: May 2023

Transient behavior of metal-insulator-semiconductor tunnel diode (MISTD) with ultra-thin metal surrounded gate (UTMSG) is discussed in this work. The influence of an important parameter, S, which is the area proportion of surrounding gate to the total gate, on the transient read current and transient capacitance window is demonstrated. Transient current is found to be larger for larger S due to more significant edge late response. By taking advantage of the unusual capacitance-voltage characteristics, improved capacitance window could be achieved. The transient current window and capacitance window of UTMSG device with S = 0.66 have been found to be 17x and 14x larger compared with planar device.
Influence of Outer Oxide Charges on the Electrostatics of Metal-Insulator-Semiconductor Tunnel Diode
Authors: Chen Kung-Chu , Lin Kuan-Wun , Hwu Jenn-Gwo
Published: May 2023

In this work, the impact of outer oxide charges on the electrostatics of metal-insulator-semiconductor tunnel diodes (MISTD) is discussed. The existence of outer oxide charges will significantly affect the critical voltage V
c of MISTD in the strong inversion region. At the bias voltage of V < V
c, the MISTD works like a traditional metal-oxide-semiconductor (MOS) capacitor. However, at the bias voltage of V > V
c, the MISTD goes to deep depletion. V
c is an important boundary for the electrostatics behavior of MISTD. We propose a model, considering the existing outer oxide charges, to calculate V
c and compare the calculated results with V
c extracted from our devices. V
c of our devices is extracted by measuring high-frequency capacitance-voltage (HFCV) at 300 kHz. It is found that the model is able to fit well with the experimental results when the amount of outer oxide charges is in the magnitude of 2.5×1011 cm-2 for our devices. The model is fundamental but helpful for analyzing and designing a MISTD.
Improved RFET Performance Using Dual-Aluminum-Contact (DAC)
Authors: Carvalho Henrique Lanfredi , Rangel Ricardo Cardoso , Sasaki Katia , Yojo Leonardo , Agopian Paula , Martino Joao
Published: May 2023

This work presents for the first time the use of dual aluminum contacts (DAC) to improve the performance of reconfigurable field effect transistors (RFET), integrating two aluminum contact in BESOI MOSFET (with and without annealing process). Using TCAD simulations, the charge density in the channel region below the aluminum source contact depends on the channel thickness and bias in the programming gate. This thickness making possible to create a hole’s channel below the Schottky aluminum contact for silicon thickness below the aluminum contacts higher than 30nm, enabling conduction in the dual aluminum contact transistor. The DAC BESOI MOSFET had a current level increase of 3 times for BESOI pMOSFET and 9 times in BESOI nMOSFET compared to using NiSi contacts
(Invited) ISFET-Based Sensors
Authors: Diniz Jose Alexandre , César Rodrigo REIGOTA , Barros Angelica Denardi , Souza Jair Fernandes , Souto Huziel Ramos , Rufino Fernando cesar , Massaroto Rentao , Swart Jacobus W
Published: May 2023

This review presents the technological evolution of devices based on Ion Sensitive Field Effect Transistors (ISFETs), which try to go along with the Metal Oxide Semiconductor FET (MOSFET) technology. Furthermore, many examples of the applications as chemical or biological sensors with different structures (planar or 3D), conduction channels (Silicon or Graphene), and dielectric gate films (SiNx, TiOx, TaOx, and AlOx) will be discussed.
Back Gate Bias Influence on BESOI ISFET Sensitivity
Authors: Duarte Pedro Henrique , Rangel Ricardo Cardoso , Ramos Daniel Augusto , Yojo Leonardo , Sasaki Katia , Agopian Paula , Martino Joao
Published: May 2023

This paper presents, for the first time, the BESOI MOSFET working as Ion Sensitive Field Effect Transistor (ISFET): the BESOI ISFET. Experimental measurements were performed with standard pH solution replacing the gate electrode. The threshold voltage becomes lower when the pH decreases (changes from basic to acid) as expected. Furthermore, the back (substrate) bias influence was studied, showing an increase in the device sensitivity (mV/pH) as a function of the back voltage. The best sensitivity value was obtained for 30 V applied in the back bias, reaching 33 mV/pH. These results demonstrates that the BESOI ISFET has electrical behavior compatible with other ISFETs.
On the Optimization of Graphene Liquid-Gate Transistors for Sensing Applications
Authors: Marquez Carlos , Fuente-Zapico Elsa , Martinez-Mazon Paula , Galdon Jose Carlos , Navarro Carlos , Gamiz Francisco
Published: May 2023

This work faces the use of graphene liquid-gate transistors as sensors. Before dealing with a functionalized surface and biological targets, achieving a reliable sensing platform within this novel material as an active channel, fabrication, lithography, and reliability have to be extensively evaluated. In this work, we have analyzed the inter-device variability and the reliability of the sensors together with the phenomena which can increase these issues under operative conditions. High quality material corroboration has been evaluated through structural characterization (optical, XPS and Raman). Then photolithography and processing for liquid-gate sensor have been performed. Finally, electrical evaluation of the devices has been carried out demonstrating reliability issues and considerable inter-device variability. We propose in this work the use of integrate-coupling effect (front and back-gate simultaneously) to alleviate the inter-device variability and reliability problems.
Enhanced UV Absorption By 2D MoS2 Nanoparticles
Authors: Almansoori Muntaser Abdelrahman , Rezk Ayman , Abdul Hadi Sabina , Nayfeh Ammar
Published: May 2023

MoS2 is a promising 2D material for solar energy harvesting applications due to its size-dependent tunable bandgap and attractive magnetic, optical, and electrical properties. This study shows an easy way to deposit a 2D layer of MoS2 nanoparticles on top of AZO/Quartz, AZO/Si, and bare Si. We investigate their UV-Vis spectral responses and potential for application in optoelectronic systems. Initial results indicate modification of the absorption spectrum over the UV-Vis range with an evident increase in the higher visible and lower UV range.
(Invited) Fabrication and Device Performance of 2.7 Kv/2.5A NiO/Ga2O3 Heterojunction Power Rectifiers
Authors: Xia Xinyi , Li Jian-Sian , Chiang Chao-Ching , Ren Fan , Pearton Stephen J
Published: May 2023

The fabrication and switching characteristics of large diameter (1mm) Ga2O3 heterojunction rectifiers with bilayers of NiO as the p-type layer are reported. The band alignment shows this is a staggered-gap system. Selective wet and dry etching was developed to allow fabrication of vertical geometry heterojunction rectifiers. A forward current of 2.5 Amperes was achieved, with a reverse breakdown voltage of 2.7 kilovolts. The on/off ratio was above 108 over a broad range of switching voltages, with a measurement-limited reverse recovery time of 100 nanoseconds.
A Capacitor-Based Synaptic Device with IGZO Access Transistors for Neuromorphic Computing
Authors: Won Jongun , Roh Youngchae , Kang Minseung , Park Yeaji , Kang Jaehyeon , Seo Hyeongjun , Joe Changhoon , Kim SangBum
Published: May 2023

Analog in-memory computing synaptic devices have been widely studied for efficient implementation of deep learning. As a candidate for a synaptic device, Si-CMOS and capacitor-based synaptic devices have been proposed. However, due to Si-CMOS leakage currents, it is difficult to achieve sufficient retention time. In our research, we verified IGZO TFT with low leakage current and capacitor-based synapses can show linear and symmetric weight update characteristics as well as excellent device variation characteristics. We also verified that IGZO TFT has a leakage current per channel width of 1μm of ~10-17A, which is much lower than the Si-CMOS, resulting in higher accuracy in deep neural network training.
Development of Molecularly Imprinted Polymer Nanoparticles with High Affinity and Its Application to Electrochemical Biosensors
Authors: Man Youyuan , Nishitani Shoichi , Sakata Toshiya
Published: May 2023

In this study, redox-labeled molecularly imprinted polymer nanoparticles (nano-MIPs) were synthesized using a solid-phase approach, templated with biomarkers for diabetes such as human serum albumin (HSA). The purpose of this research was to develop enzyme-/antibody-free electrochemical biosensors with the nano-MIP-coated Au electrodes. The synthesized HSA–nano-MIP (HNM) was analyzed for its chemical composition, size, affinity, and electrochemical property, and was tethered on gold via a coupling chemistry. The results of cyclic voltammetry analysis revealed that electron transfer occurred on the HNM-immobilized Au electrode through physical displacement of the redox centers within HNM, which hopped from one redox center to an adjacent redox center, a process known as bounded diffusion. In this paper, we present a promising approach to developing sensitive and selective electrochemical biosensors for diabetes detection.
Acinetobacter Baumannii Detection Using A Bio-FET Device: Towards Healthcare Infection Management
Authors: Cheng John ChauFu
Published: May 2023

This study highlights the need for a fast and sensitive diagnostic technique for detecting Acinetobacter baumannii, a common cause of healthcare infections. The electrical double layer (EDL)-gated field-effect transistor-based biosensor (BioFET) is a promising tool that can detect the bacteria quickly and with high sensitivity. Using a portable BioFET device, we designed a specific DNA probe to detect the complementary DNA of Acinetobacter baumannii, which was conjugated with red fluorescence Cy3 to compare sensitivity between bioFET and fluorescent system. The results showed that the device can detect much lower concentration of cDNA than the fluorescent system, indicating its potential as a tool for detecting healthcare-associated infections caused by Acinetobacter baumannii. Thus, the use of portable BioFET devices could improve patient outcomes and reduce the risk of hospital-acquired infections.
Fabrication of Aptamer-based Field Effect Transistor Sensors for Detecting Mercury Ions
Authors: Wang Yu-Lin , Zeng Guan-Cheng , Lee Chun-Ta , Lin Chia Kai , Kuo Tzu-Han , Paulose Akhil K , Lin Zong-Hong , Hung Sheng-Chun
Published: May 2023

This study presents an extended gate aptamer-based FET sensor for the detection of mercury ions in water. Heavy metal contamination in water can pose a severe threat to human health, and mercury ions are particularly dangerous as they can accumulate in the human body and cause serious health problems. The sensor provides high selectivity and sensitivity, even in the presence of other heavy metals, and achieves a detection limit of 0.2 ppm using a 500 μm x 500 μm gate sensing area. This cost-effective and efficient method can contribute to the mitigation of environmental pollution and the protection of public health.
Oxygen Evolution Activity on Mo Added Zr Oxide Catalyst in Alkaline Solution
Authors: Matsuzawa Koichi , Nozaka Atsushi , Hirose Kazuya , Ishihara Akimitsu
Published: May 2023

In order to development of alternative anode of alkaline water electrolysis, we have focused on Zr oxide-based catalyst and investigated the activity of oxygen evolution reaction (OER) on Mo added Zr oxide-based catalyst in 7 M KOH at 30 oC. Mo added Zr oxide-based catalyst on Ti rod was prepared by the arc plasma deposition (APD) and R.F. sputtering. Compared with Mo-Zr binary oxide-based electrode (Mo-ZrOx) fabricating by the sputtering procedure, the MoO3 by APD on ZrOx by sputtering (MoO3/ZrOx) with TaOx by sputtering as an interlayer showed higher OER activity, and it reached over 1 mA cm-2 of OER geometric current density at 1.8 V vs. RHE. The Tafel slope of OER on MoO3/ZrOx was 81 mV dec-1 while that on Mo-ZrOx was over 200 mV dec-1. According to results from electrochemical impedance spectroscopy, the charge transfer resistance of MoO3/ZrOx was much smaller than that of Mo-ZrOx.
Insights into the Structure - Composition - Activity Relationship of PtCo Alloy Nanoparticles towards Oxygen Reduction Reaction (ORR)
Authors: Janssen Marek , Klein Jochen , Dworzak Alexandra , Blaseio Sonja , Oezaslan Mehtap
Published: May 2023

PtCo alloy nanoparticles (NPs) are widely used as highly active oxygen reduction reaction (ORR) catalysts for PEMFCs. Despite large efforts, the critical relationships between structure, composition and ORR performance of catalyst materials are not fully understood to date. In this study, we prepared two PtCo alloy NP catalysts with an atomic ratio of 1:1 using wet-impregnation route by varying the annealing parameters under reductive conditions. The as-prepared PtCo alloy catalysts were structurally characterized using ex-situ HR-TEM, EDX, XRD, and EXAFS. We show that the annealing temperature and holding time affect the particle size, composition and homogeneity of the PtCo NPs. With higher annealing temperature and longer holding time, the particle size grows from 3.1 ± 0.7 nm (400 °C, 4 h) to 4.4 ± 0.6 nm (800 °C, 6 h) and simultaneously, the alloy formation within the NPs improves. After electrochemical activation in 0.1 M HClO4, the electrochemically active Pt surface area (ECSA) for activated PtCo T400 (65 ± 8 m2 gPt
-1) is slightly lower than that for pure Pt/C (70 ± 11 m2 gPt
-1), but significantly higher than that for the activated PtCo T800 (50 ± 4 m2 gPt
-1). However, the activated PtCo T800 shows the highest ORR mass activity (0.56 ± 0.14 A mgPt
-1 at 0.9 VRHE, iR-free) than the activated PtCo T400 (0.43 ± 0.03 A mgPt
-1) and Pt/C (0.24 ± 0.04 A mgPt
-1). Altogether, we provide deeper understanding of the structure - composition - ORR activity relationships for two differently annealed PtCo alloy catalyst materials.
Impact of Aluminum Modification on the Dielectric Properties of Graphene Oxide Membrane: Different Al Source
Authors: Stehle Yijing Yin
Published: May 2023

The high dielectric constant and low dielectric loss of Graphene oxide (GO) membranes made them good dielectric separator membranes for developing high performance energy storage and transfer devices. Better understanding and be able to tailor the dielectric properties of the GO membrane is crucial for its dielectric applications. The interaction variation of Al3+ from different source with the functional group on the GO sheets could lead to different modification effects on the dielectric properties of GO membranes. Here, the Al3+-modification, where aluminum metal foil, chloride salt, and alumina serve as different Al3+ source, are applied to tailor the dielectric properties of GO membranes. The dielectric constant and dielectric loss of GO and Al3+ modified GO(AGO) in the frequency range from 0.01 Hz to 105 Hz is studied. The capacitance of a simple dielectric capacitor fabricated by sandwich the GO and AGO membrane in between carbon paper are evaluated to estimate the effect of dielectric separator membrane variation on the electrochemical performance of the capacitor. This study provides a facile and effective strategy to tailor the dielectric property of GO membrane and demonstrate the possibility of designing dielectric GO membrane with controllable dielectric performance.
(Invited) Introduction of National Projects Concerning Fuel-Cells in Japan
Authors: Fujii Yosuke
Published: May 2023

In 2017, the Japanese Government formulated the “Basic Hydrogen Strategy” as a future vision that Japan should aim to achieve by 2050. It also serves as an action plan through to 2030 to realize the vision in order to accomplish the first hydrogen society in the world. With the release of the Basic Hydrogen Strategy, the Government also revised the “Strategic Road Map for Hydrogen and Fuel Cells” in 2019.
Ni- and Ni-Sn Anode Porous Layers for SOFCs Operating with Carbonaceous Fuels
Authors: Rose Christian , Mastropasqua Luca , Brouwer Jack
Published: May 2023

Nickel metal layers with various morphologies have been investigated as electrical contact, electrocatalyst, and catalyst layers for high temperature hydrogen electro-oxidation and heterogeneous reactions, such as steam methane reforming and water gas shift, in high temperature fuel cells supplied by carbonaceous fuels of various nature. Ni metal alloys, with various dopant concentrations, have been studied to increase metal nickel tolerance to carbon deposition, which is thermodynamically favored in SOFC fed with a steam/methane molar ratio <2.0. The goal of this research is to compare the electrochemical performance, the catalytic activity towards steam methane reforming reaction yield, and the resistance towards the Boudouard reaction for solid carbon formation of a Ni-based SOFC: i) without Ni porous layer; ii) with a 200 μm thick Ni porous mesh; iii) with a 200 μm thick NiSn porous mesh.
Solid Oxide Stack Development at Elcogen
Authors: Noponen Matti , Puranen Jouni , Alfano Antonio , Granö-Fabritius Hanna
Published: May 2023

Elcogen solid oxide stacks are key enablers of the transition to a new energy scenario. This work provides an overview of the latest development activities at Elcogen. Throughout this manuscript, advancements on the stack level will be discussed with main focus on the flexibility and robustness of the elcoStack® in different operating modes. Such advancements are contextualized within the scaling up activities of the company, which will prepare Elcogen for the large scale deployment of solid oxide technology.
Performance Analysis Method for PCFC Considering Leak Current and Application to 1000hr Endurance Test
Authors: Yoshikawa Masahiro , Tsuji Kentaro
Published: May 2023

We estimate the internal leakage current in PCFC mode, and report the results of a study on a performance analysis method that takes account of the leakage current. As results, the leak current increased with the supplied hydrogen, oxygen, and the steam concentration on the fuel electrode side, and the leak current tended to decrease only with the steam on the air electrode side. Also, the higher the temperature, the more remarkable the change was observed in leakage current. Moreover, it was clarified that the cathode overvoltage greatly increases as the temperature decreases. From the result of 1000hr endurance test, it was revealed that the decrease output voltage was increase in the fuel electrode reaction resistance.
Reversible Solid Oxide Cells: Cycling and Long-Term Durability of Air Electrodes
Authors: Ikegawa Kazutaka , Miyara Kengo , Tachikawa Yuya , Lyth Stephen Matthew , Matsuda Junko , Sasaki Kazunari
Published: May 2023

Durability and diffusion of various elements in the LSCF-based air electrode of reversible solid oxide cells (r-SOC) are studied. The r-SOC cycling durability tests are conducted by continuously switching between SOFC and SOEC operations. The performance and durability of air electrodes are verified especially after ca. 500 r-SOC cycles.
Investigation of La0.65Ca0.35FeO3−δ
as a Co-Free Cathode for Protonic Ceramic Fuel Cells with Yb-Doped BaZrO3 Electrolyte
Authors: Watanabe Konosuke , Shimada Hiroyuki , Yamaguchi Yuki , Nomura Katsuhiro , Sumi Hirofumi , Kagomiya Isao , Mizutani Yasunobu
Published: May 2023

Although cobalt-containing cathode materials are widely used in protonic ceramic fuel cells (PCFCs) because of its high catalytic activity, cobalt diffuses into the proton-conducting electrolyte, thereby decreasing the power generation performance. To achieve a higher power generation performance in PCFCs with a cobalt-free cathode, we fabricate anode-supported PCFCs using BaZr0.8Yb0.2O3–δ
as the electrolyte, and composite cathodes of La0.65Ca0.35FeO3−δ
(LCaF) and BaZr0.1Ce0.7Y0.1Yb0.1O3−δ
(BZCYYb). The mixing weight ratios of LCaF and BZCYYb are varied to 80:20, 70:30, 60:40, 50:50, and 30:70. The PCFC with LCaF–BZCYYb (60:40) composite cathode exhibits the highest power generation performance in the operating temperature range of 500–700 °C with a maximum power density (MPD) of 0.41 W cm−2 at the operating temperature of 600 °C. This MPD value is higher than that obtained in our previous study using a PCFC with a La0.6Sr0.4Co0.2Fe0.8O3−δ
–BZCYYb composite cathode.
Correlation Between Microstructure and Performance of GDC-Based Electrodes
Authors: Sciazko Anna , Komatsu Yosuke , Shimura Takaaki , Sunada Yusuke , Shikazono Naoki
Published: May 2023

Gadolinium doped ceria (GDC) is a promising material for solid oxide cells. GDC is conventionally used as an ionic conductor in composites with electron-conducting metal or perovskite materials. However, recent studies demonstrated that pure GDC fuel electrodes can achieve substantial power density if their microstructure is appropriately designed. Four different types of GDC electrodes are investigated in this study, including conventional Nickel (Ni)-GDC composite, GDC-perovskite composite, GDC deposited with Ni nanoparticles and pure GDC. The test results show a clear correlation between GDC surface area and electrode performance. At the same time, the electrode active thickness depends on the electrode microstructure. It is in the range of 5 µm for the nano-size GDC electrodes. When the GDC electrode is thicker than the active thickness, it results in large ohmic resistance due to the electronic conduction in the outer layer.
Scenario Evaluation of Reversible Solid Oxide Cells Integrated with Local Renewable Energy Sources: Assessment of Different Coupling Applications
Authors: Marino Francesco , Della Pietra Massimiliano , Monforti Ferrario Andrea , Santoni Francesca , Cigolotti Viviana , Jannelli Elio
Published: May 2023

This work is focused on the analysis of the integration of reversible Solid Oxide Cells (rSOCs) for power grid flexibility and renewable sources exploitation purposes. Firstly, the area with the highest mismatch between renewable generation and load in Italy has been identified, making sure that, from a technical point of view, the use of an rSOC system can prove to be advantageous. An experimental campaign on a 0.4 kW SOC short-stack was carried out, with the aim to replicate, by means of dedicated tests, the operating conditions of the larger scale SOC system designed to absorb the abovementioned misalignment.Technology-wise, the high potential of the rSOC for this application has been proven: the results show an efficiency of the system estimated to be over 55% in fuel cell mode, with a water conversion rate of 89%. Moreover, the designed system appears to fit perfectly into the real scenario, with an annual operation of 8700 hours.
Evaluation of SOFC Durability Against Simultaneous Heat/Load Fluctuations
Authors: Joh Dong Woo , Hussain Amjad , Kim Tae-Hun , Shin Ji-Weon , Hong Jong-Eun , Lee Seungbok , Lim Tak-Hyoung , Song Rak-Hyun
Published: May 2023

Variable renewable energy sources (solar, wind, etc.) are difficult to maintain efficient hierarchical operation and stable power quality from the perspective of the power system. In preparation for this increase in the proportion of renewable energy, it is necessary to prepare counterplan for power system intelligence and flexibility, such as power backup systems, power storage devices, smart control, and demand response. It is expected that control the volatility of renewable energy and supply-demand balance can be solved by producing/storing hydrogen using idle power and generating electricity using fuel cells. High-efficiency SOFC technology that can manage with daily cycle load fluctuations is the best alternative. In this work, the goal is to develop basic technologies for energy network systems that can respond to daily cycle power fluctuations of renewable energy and increase system stability through SOFC cell/stack design and durability enhancement. In this study, in order to secure the ability to cope with the variability of the power system, it is intended to present durability evaluation criteria for simultaneous heat and load cycles. Stack evaluation was performed in the current range of 0.25 ~ 0.50 A/cm2 in the case of the load cycle test and 500 ~ 700 °C in the case of the temperature cycle test.
Phase Segmentation of Ni/YSZ Anode for Solid Oxide Fuel Cells by Deep Learning
Authors: Wang Yige , Matsui Yodai , Hosomizo Akihito , Kishimoto Masashi , Han Minfang , Iwai Hiroshi
Published: May 2023

A deep learning network is implemented for the phase segmentation of Ni/YSZ anode of solid oxide fuel cells (SOFCs), as manual segmentation of focused ion beam-scanning electron microscopy (FIB-SEM) images is time-consuming. Segmentation is performed on two samples with different volume ratios of Ni to YSZ. The mean intersection over union (mIoU) reaches 0.9363, indicating good agreement between the predicted images and the manually segmented images. Furthermore, the impact of image augmentation on segmentation accuracy is investigated, and it is found that augmentation is necessary when the number of images in the training set is small or the training and testing sets come from different samples. Furthermore, mixing a sixth of manually segmented images from a new sample into the training set can significantly improve the accuracy of automated segmentation for the new sample. This strategy reduces the number of images requiring manual segmentation and improves processing efficiency.
Recent Developments of the International Future Lab of Hydrogen Economy: Using Artificial Intelligence (AI) Based Machine Learning (ML) in r-SOC Development
Authors: Peksen Murat , Steinrücken Benjamin , Spliethoff Hartmut
Published: May 2023

Current r-SOC research places special emphasis on the integrated approach of traditional numerical methods like CFD and accelerated AI methods. Using experimentally validated numerical models, the complex thermochemistry of auxiliary components containing syngas was evaluated. This method is used to generate data for the successful development and training of AI-based machine-learning models. Analyses shed light on the interactions between process variables in order to improve and prepare SOC-ready fuel, which is crucial for operation success. A recently developed ML model is utilised effectively to forecast and optimise reforming processes with various fuel constellations, including syngas compositions containing oxygen. Consequently, the results contribute to a greater understanding and qualitative benefits of preparing high-quality, pure syngas, improved fuel utilisation advancing sustainable research, and safe, consistent r-SOC operation. Consequently, early availability of valuable information is achieved. In addition, the strategy reduced prohibitive experiments, which contributed to the sustainable utilisation of resources.
Novel SOFC Repeating Unit Design for the Uniform Distribution of Temperature and Thermo-Electrochemical Reaction Zone in a Commercial Scale Stack
Authors: Lee Wooseok , Hong Jongsup
Published: May 2023

Solid oxide fuel cells (SOFC) have been spotlighted as eco-friendly energy sources due to their various advantages, but performance degradation occurring in high-temperature operations and hydrocarbon-based fuel conditions have become obstacles to commercialization. In this study, a novel SOFC stack design is proposed to alleviate the nonuniform distribution of temperature and chemical reaction which can accelerate the degradation of the conventional crossflow type stack. We compared the conventional and the novel SOFC stack design through three-dimensional multiphysics simulation analysis. Compared to the conventional design, the standard deviation of temperature, chemical reaction rate, and fuel species concentration in the novel design decreased by 65.07%, 20.28%, and 25.14%, respectively, showing the advantage of the novel design.
From Ideal to Stack-like Contacting of an SOC
Authors: Grosselindemann Cedric , Esau Daniel , Dorn Marvin , Bauer Frank Manuel , Wissmeier Lena , Weber Andre
Published: May 2023

The performance of an SOC depends on the testing environment. Regarding single cell tests with ideal contacting (gold and nickel meshes) and inert flow fields (Al2O3), the performance is limited by the intrinsic losses in the cell as contact losses and any poisoning effects are minimized. In an SOC-stack exhibiting metallic interconnectors, the performance is furthermore affected by contact resistances and limitations in gas supply. In this contribution single cell testing is extended to a stack-like contacting applying three different metallic interconnectors (Crofer 22 APU, ASTM 441 and UNS S44330) with and without a cerium-cobalt PVD-coating. Cell performance and losses are analyzed by IV-characteristics, impedance spectroscopy and DRT analysis. For all uncoated interconnectors, significant performance losses due to increased contact losses and air electrode polarization were observed. With the CeCo-coating losses could be drastically reduced leading to a cell performance close to the ideal case for all three steel grades.
Techno-Economic Optimization of SOC Design and Operating Conditions in a Solid Oxide Fuel Cell-Gas Turbine Hybrid System
Authors: Rosner Fabian , Samuelsen Scott
Published: May 2023

Solid oxide fuel cell-gas turbine (SOFC-GT) hybrid systems can reach exceptionally high fuel-to-electricity conversion efficiencies while emitting virtually zero criteria pollutants. Due to these characteristics and their fuel-flexibility, SOFC-GT hybrid systems are seen as a key technology in sustainable power generation. In this work we explore SOFC cell design parameters that can synergistically reduce thermal stress and cost, as well as system-level design strategies to maximize economic performance. Results show that NG-fueled hybrid systems can reach efficiencies of 75%-LHV at a cost-of-electricity of 77.73 $/MWh. A similar biogas system with integrated anaerobic digester and biogas upgrading resulted in an efficiency of 53%-LHV and a cost-of-electricity of 137.19 $/MWh.
Nanostructured LSC Thin Film Electrodes with Improved Electrochemical Performance and Long-Term Stability
Authors: Bagarinao Katherine Develos , Celikbilek Ozden , Kerherve Gwilherm , Fearn Sarah , Skinner Stephen J , Kishimoto Haruo
Published: May 2023

Nanostructured La0.6Sr0.4CoO3-

δ

(LSC) thin film electrodes exhibit exceptionally high oxygen surface exchange properties, surpassing those of conventional microscale electrode structures, which are desirable for application in solid oxide cells (SOCs). Here, towards the goal of improving the long-term stability of electrochemical performance of nanostructured LSC thin films, a systematic investigation of the effect of processing temperatures on long-term stability was carried out. By varying the deposition temperature (from 500 °C to room temperature), the as-grown characteristic nanostructures of LSC thin films prepared using pulsed laser deposition can be tuned from highly dense nanocolumnar grains to nanofibrous structures with high porosity. From the comparison of the properties of the as-grown films and those annealed at 700 °C for 300 h, it was revealed that LSC thin films prepared at lower deposition temperatures are less prone to the grain sintering effect and cation interdiffusion and exhibit better interfacial stability and improved long-term performance.
Performance Evaluation of an Anode-Supported Solid Oxide Fuel Cell Short-Stack Operating with Different Hydrogen-Natural Gas Blends as Stationary Combined Heat and Power System
Authors: Monforti Ferrario Andrea , Santoni Francesca , Marino Francesco , Alfano Antonio , Stenius Julius , Noponen Matti , Neubauer Raphael , Cigolotti Viviana
Published: May 2023

In the perspective of the transition of gas grids towards hydrogen/natural gas blends or even pure hydrogen, Solid Oxide Fuel Cells “SOFC” could play a crucial role as efficient and clean stationary Combined Heat and Power (CHP) systems, flexibly operating on different feedstocks. A SOFC short stack is analyzed experimentally under different fuel gas compositions which emulate different gas grid transition scenarios. The testing campaign is defined with the aid of a preliminary system-level simulation which assesses system architecture and operating strategy (off-gas recirculation, external reforming, etc.). Experimental tests (polarization curves and performance/efficiency maps) are run in different operating conditions in terms of fuel utilization, current loading and temperature in three gas composition scenarios. Experimental results show that – albeit the highest voltage/power is obtained with the 100%H2 scenario – the efficiency may be higher with 100%NG and blend scenarios, due to the lower energy content of the input fuel.
Characterizing the Performance of kW-Scale Multi-Stack Solid Oxide Fuel Cell Modules through Modeling
Authors: Floerchinger Gus , Cadigan Chris , Sullivan Neal P. , Braun Rob J
Published: May 2023

The development of commercial SOFC systems often utilizes models of a single representative SOFC stack to simulate the system’s prime mover. In practice, however, these representative single-stack SOFC models fail to consider effects due to the reality of multi-stack power modules needed to construct commercial-scale systems. Effects such as flow maldistribution, inter-stack heat transfer, and area-specific resistance (ASR) variation between stack units within a single module will create deviations in performance from a single stack-based system simulation. The following outlines efforts to consider these thermofluidic effects and the associated performance deviations of a novel 30kWe SOFC multi-stack module using models in the gPROMS Modelbuilder® environment. Specifically, the impacts of gas manifolding, heat loss, and stack placement are investigated, and their potential impacts are discussed.
Experimental Study on High-Efficiency Microtubular Solid Oxide Fuel Cell Stacks Using Various Fuels
Authors: Shi Jixin , Yao Yue , Zhang Ruiyu , Wang Yuqing , Fan Junhua , Shi Yixiang , Liang Bo , Cai Ningsheng
Published: May 2023

Microtubular solid oxide fuel cell (mTSOFC) is a clean and low carbon emission power generation technology that has great prospects in the field of portable power generation. Improving the efficiency and broadening the variety of available fuels can significantly improve the performance of portable power generation devices based on mTSOFC. In this study, mTSOFC stack assembled by mounting modular sub-stacks in an array on a designed fuel/air distribution base were tested. By changing the connection of the current collection nodes, the influence of circuit connection modes on the overall output performance of the stack was studied. At a temperature of 700℃ and a fuel feed of hydrogen, the mTSOFC stack composed of 6 sub-stacks can achieve a maximum power of 353W. Fuel cascade utilization was realized by transferring the spent fuel gas from the upstream sub-stacks to the downstream sub-stacks. A maximum power generation efficiency of 45.67% was achieved in the two-cascade stack. The feasibility of using hydrogen, ammonia, propane and diesel as fuel for the mTSOFC stack has also been experimentally verified. A total continuous discharge time of 21h was achieved at an average power ≥ 190W under ammonia feeding conditions.
Design and Fabrication of an Easily Assembled Anode Supported Microtubular SOFC Stack
Authors: Zhang Ruiyu , Wang Yuqing , Shi Jixin , Shi Yixiang
Published: May 2023

Anode-supported micro-tubular solid oxide fuel cell has shown many advantages which make it suitable for portable devices. In this study, we developed a micro-tubular SOFC stack and module using a metallic current collector and interconnector which enabling pluggable modular design pattern. In order to ensure the sealing performance, we adopted the low-temperature sealing method and the temperature at the sealing position is under 130℃ while the stack is operated at 750℃.The stack was made of 8 micro-tubular cells, which were connected in series and parallel, in a 2×4 array. The open circuit voltage (OCV) was above 4.22V, thus the single cell’s OCV value could reach about 1.06V. The stack module can be further connected in series or in parallel to satisfy larger power requirements.