bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical Investigation of Photovoltaics Cooling Using Wicking Channels
Authors: Poudel Sajag , Ranjan Durgesh , Zou An , Maroo Shalabh C.
Published: July 2021

The performance of a photovoltaics (PV) panel is dependent on its surface temperature. Cooling the PV panel can substantially enhance its efficiency and thus the output power. Thermal management with spray cooling in porous nanochannels device offers a high heat flux removal capability due to thin-film evaporation occurring at micro/nano scale menisci. By integrating the nanochannels device on the back face of the PV panel, it is possible to dissipate heat from the PV panel so that it operates within a desired range of temperature values. In the present work, we utilize the results of spray cooling on such nanochannels device and perform the numerical investigation of PV panel cooling and enhancement in power output. A range of solar irradiation 500–900 W/cm2 is considered and the transient state transport equation for energy balance is solved numerically for 6 cases. With the applied thermal management using nanochannels device, the power output of PV panel is enhanced by ∼27% for the maximum solar irradiation of 900 W/cm2.
A Study of Wall Temperature Jump Using UGKS Simulation With Diffuse-Specular Maxwell-Type Boundary
Authors: Dai Lianfu , Wu Huiying
Published: July 2021

As the Maxwell-type boundary treatment can automatically capture temperature jump on boundary, it is widely used in gas flow simulation like Lattice Boltzmann method and Direct simulation Monte Carlo method. In present study, diffuse-specular Maxwell-type boundary with a diffusive fraction (a), which decides the mechanism of interaction between gas molecules and boundary, is realized in UGKS simulation. This diffuse-specular boundary can recover diffuse Maxwell boundary when a = 1.0, which proves the reliability of present boundary treatment. The influence of diffusive fraction on wall temperature jump under Knudsen number ranging from 0.001 to 1.0 is tested. The test cases are steady and unsteady state conditions of heat conduction and Couette flow between two infinite plates setting at specified temperatures. It is found that: 1) for cases of Knudsen number ranging from 0.01 to 1.0, owing to the loss of influence from equilibrium part on evolution of boundary gas distribution, the relative temperature jump increases when diffusive fraction varies from 1.0 to 0.25, this phenomenon is especially obvious on extreme point part in unsteady state cases; 2) for cases of Knudsen number equaling to 0.001, diffusive fraction has no significance influence on temperature jump as the temperature jump is less noticeable for such condition. Present study will help the further researches of heat transfer in rarefied gas.
A Simplified Numerical Approach to Characterize the Thermal Response of a Moving Bed Solar Reactor
Authors: Al Sahlani Assaad , Randhir Kelvin , Ozalp Nesrin , Klausner James
Published: July 2021

Concentrated solar thermochemical storage in the form of a zero-emission fuel is a promising option to produce long-duration energy storage. The production of solar fuel can occur within a cylindrical cavity chemical reactor that captures concentrated solar radiation from a solar field. A heat transfer model of a tubular plug-flow reactor is presented. Experimental data from a fixed bed tubular reactor are used for model comparison. The system consists of an externally heated tube with counter-current flowing gas and moving solid particles as the heated media. The proposed model simulates the dynamic behavior of temperature profiles of the tube wall, gas, and particles under various gas flow rates and residence times. The heat transfer between gas-wall, solid particle-wall, gas-solid particle, are numerically studied. The model is compared with experiments using a 4 kW furnace with a 150 mm heating zone surrounding a horizontal alumina tube (reactor) with 50.8 mm OD and a thickness of 3.175 mm. Solid fixed particles of magnesium manganese oxide (MgMn2O4) with the size of 1 mm are packed within the length of 250 mm at the center of the tube length. Simulation results are assessed with respect to fixed bed experimental data for four different gas flow rates, namely 5, 10, 15, 20 standard liters per minute of air, and furnace temperatures in the range of 200 to 1200 °C. The simulation results showed good agreement with maximum steady state error that is less than 6% of those obtained from the experiments among all runs. The proposed model can be implemented as a low-order physical model for the control of temperature inside plug-flow reactors for thermochemical energy storage (TCES) applications.
Effect of Variation of Pin-fin Height on Jet Impingement Heat Transfer on a Rotating Surface
Authors: Bhansali Pratik S. , Ekkad Srinath V.
Published: July 2021

Heat transfer over rotating surfaces is of particular interest in rotating machinery such as gas turbine engines. The rotation of the gas turbine disc creates a radially outward flow on the disc surface, which may lead to ingress of hot gases into the narrow cavity between the disc and the stator. Impingement of cooling jet is an effective way of cooling the disc and countering the ingress of the hot gases. Present study focusses on investigating the effect of introducing pin-fins over the rotating disc on the heat transfer. The jet Reynolds number has been varied from 5000 to 18000, and the rotating Reynolds number has been varied from 5487 to 12803 for an aluminum disc of thickness 6.35mm and diameter 10.16 cm, over which square pins have been arranged in an inline fashion. Steady state temperature measurements have been taken using thermocouples embedded in the disc close to the target surface, and area average Nusselt number has been calculated. The effects of varying the height of the pin-fins, distance between nozzle and the disc surface and the inclination of the impinging jet with the axis of rotation have also been studied. The results have been compared with those for a smooth aluminum disc of equal dimensions and without any pin-fins. The average Nusselt number is significantly enhanced by the presence of pin fins. In the impingement dominant regime, where the effect of disc rotation is minimal for a smooth disc, the heat transfer increases with rotational speed in case of pin fins. The effect of inclination angle of the impinging jet is insignificant in the range explored in this paper (0° to 20°).
Effect of Protuberances in the Heat Transfer Enhancement in Mini-Channels
Authors: Cruz Diaz Ariel , Carbajal Gerardo
Published: July 2021

This study presents the effects of adding an array of protrusions in a microchannel for heat transfer enhancement. The presence of mini-channels increases the overall heat transfer area and boosts the mixing development near the solid-fluid interaction; therefore, it can remove more heat than conventional mini-channels without protuberances. A numerical study proved that protuberances in a mini-channel increase the heat transfer performance by disturbing the relative fluid motion near the solid wall. The numerical simulation was performed with three different protuberances arrays: aligned, staggered, and angular. Each array consists of a thin flat plate with a hemispherical shape; the working fluid and the solid materials were water and copper. The study also includes the effect of different Reynolds numbers: 1,000, 1,500, and 2,000. Three heat inputs were applied in the numerical simulation; these were 1W, 3W, and 5W. The study was compared with a simple microchannel with non-protuberances to analyze the microchannel performance regarding heat removal and pressure drop. For heat transfer performance, the best array was the staggering array with a maximum heat removal increase of 5.26 percent. In terms of pressure drop performance, the best array was the aligned array, with a maximum increase of 34.73 percent.
Real Time Rainfall Monitoring for Pipeline Geohazards
Authors: Ferris Gerry , Grover Patrick , Zahradka Aron
Published: July 2021

Oil and gas pipelines are subjected to multiple types of geohazards which cause pipeline failures (loss of containment); two of the most common types occur at watercourse crossings and at landslides.

At watercourse crossings, the most common geohazard which causes pipeline failures is flooding during which excessive scour may result in the exposure of the buried pipeline and if the exposure results in a free spanning pipeline, then this may fail due to fatigue caused by cyclic loading from vortex-induced vibration. Fortunately the free span length and water velocity combinations that lead to failure can be defined and can be used to identify the flood discharge that should be monitored for in order to trigger actions to manage the hazard and avoid failure. Most watercourse crossings in a pipeline network are on ungauged watercourses and necessitate the use of a proxy gauged watercourse. The “proxy” gauged watercourse is used to infer whether flooding is occurring on the ungauged crossing, and the owner can take appropriate actions. Often the proxy gauged watercourse is too far away or the watercourse may not be representative of the crossing of concern (e.g. large difference in the drainage areas). Real-time rainfall data can be used in conjunction with streamflow monitoring to determine when extreme precipitation has occurred within the ungauged watercourses catchment which may result in flooding.

Where pipelines cross landslide prone areas, large scale movements can be initiated, or slow on-going movement rates increased when extreme rainfall occurs. The definition of the extreme rainfall event for slope sites is the key component of providing a suitable warning of potentially dangerous conditions; shallow slides can be caused by short term events from sub-hourly to 3 day duration precipitation events whereas large deep seated (creeping) landslides can be driven by annual and intra-annual rainfall amounts. Monitoring of real time rainfall can be used to determine when extreme rainfall occurs at a landslide site.

The density of in-situ weather stations collecting real-time rainfall data prevents the application along remote sections of pipeline routes and within large sections of Canada. Gridded real time rainfall from quantitative precipitation estimations which integrate a multiple data sources including in-situ, numerical weather prediction, satellite and weather radar, can be used to overcome this problem and provide warnings when pre-determined rainfall thresholds are exceeded on a site-specific basis.
Practical Cases: Geohazards on RoW Generated by Third Party Damage
Authors: Oliveros Francisco , Malpartida John , Melo Alberto , Rosario Christian , Mecatti Marcos
Published: July 2021

Camisea Pipeline Transportation System (PTS) in Peru, owned by Transportadora de Gas del Perú (TGP) and operated by Compañía Operadora de Gas (COGA), begins in the Amazon rainforest, crosses the Andes Mountains (4850msnm) and finally descends towards the Pacific coast. The PTS has been operating for more than 10 years and it has Natural Gas (NG) and Natural Gas Liquids (NGL) transportation pipelines. The NG pipeline is 888km long which includes two Loops (105km and 18km in the coast and mountain sectors, respectively). NGL pipeline is 557km long.

From the beginning (0 km) to 210 km, the Right of Way (RoW) is located in the geotechnical context of the Amazon rainforest. Then, between km 210 and km 420, the PTS crosses the mountain chain of the Andes. Finally, between km 420 and Km 730 the RoW is located on the Peruvian Pacific coast.

TGP’s operation of the PTS identifies, analyzes and controls the different types of threats that can affect the integrity of the pipelines. The operation is developed according to international standards defined in the Pipeline Integrity Management (PIM) of the operation. Consequently, hazards such as Third Party Damage (TPD), geohazard, external and internal corrosion, among others, are analyzed.

However, associated to the economic growth and development of Peru, there have been some cases where the intervention of a person, community or industrial activity in the surroundings of the RoW has resulted in the level of geohazards are spontaneously modified and activated. Consequently, the degree of stability of the RoW is necessary to analyze the integrity of the NG and NGL pipelines.

This article describes the occurrence of some practical cases where there was a change in the stability of the RoW of the TGP’s PTS triggered by activities related to TPD. It is highlighted that the identification, analysis, definition and execution of mitigation actions are carried out in a transversal way which involves the participation of different operational areas such as: Integral Maintenance, Geotechnics, Integrity, Social Management, among others. All the activities are done with the approach of keeping the balance between community, environment and infrastructure.

Some of the cases considered are: Flood and scour of the RoW triggered by the failure of a water tank in an industrial area, scour of channels due the obstructions and an unstable slope process generated by constructions near the RoW.

Today, the operation develops activities in order to mitigate geohazards generated by TPD. Some of these activities are, among others: Social awareness, technical talks, agreements with industrial and local administration entities, geotechnical maintenance and monitoring. In addition, it is highlighted that all the mentioned mitigation actions are carried out in a transversal manner between different operational areas. Afterward, the collected information is properly saved in the Geographic Information System database.
The Contribution of In-Line IMU Inspection to Geohazard and Crack Management Strategies
Authors: Young Andy , Wilde Andrew , Grosmann Ivan
Published: July 2021

Geohazards and external loads are a significant threat to the integrity of pipelines in hilly terrain, at river crossings and where ground subsidence is taking place. Well designed pipelines can tolerate strains that exceed the nominal strain of 0.5% that corresponds specified minimum yield strengths, however the presence of weld defects and stress corrosion cracking can reduce the load capacity dramatically. Welds that are to specification but are under-matched on actual strength to the adjacent parent pipe have also been recognised as potentially vulnerable to low strain failures in high strength pipes.

Modern pipelines in terrain susceptible to geohazards normally include design studies to identify and avoid or mitigate the threats. Surveillance of the right-of-way is also routinely carried out for pipelines with good integrity management practices, and particularly for major strategic lines. In-line inspection using an inertial measurement unit (IMU) is a well-known method to detect ground movement loads and contributes to the integrity management of pipelines.

In this paper we illustrate :

1. How IMU inspection is an important tool in the management of geohazards and how it compliments other methods of geohazard assessment.

2. How locations of elevated pipe strain are identified and evaluated for external loading threats, and can be aligned with other data sets that indicate the pipeline load capacity.

3. How the locations of bending strain can be prioritised for further action.

4. How the loading profile in the pipeline can be incorporated into crack management strategies in order prioritise locations for further investigation or assessment.
Remote Geotechnical Evaluation of Rights of Way of Hydrocarbon Transmission Lines
Authors: Amórtegui Gil José Vicente
Published: July 2021

Due to the health emergency currently affecting the planet, it has been impossible for engineering specialists to carry out direct inspections of the land. During this time, it has been necessary to develop techniques and procedures that allow engineers to obtain information from the land remotely. Here, they are supported by the technology that allows them to record images remotely via drones and communicate so they can perform inspections by auxiliary field personnel, directed at a distance by specialists.

To do this, a preliminary flight plan is defined, based on the experience and knowledge of the terrain by the specialist and the visual of the drone is transmitted via the Internet from a PC in the field. Later, which images to record and the sites that require more detail or a direct inspection by the field assistant are defined. Finally, the field assistant transmits the images of the inspection. In this way, the specialist’s training and experience, the operational ease of the drone, and the skill of the field staff are taken advantage of.

This article details the procedure for remote inspection, and ways in which it can even be extended to corridor recognition tasks to define the layout of rights of way.
Molecular insights on confined water in the nanochannels of self-assembled ionic liquid crystal
Authors: Ishii Yoshiki , Matubayasi Nobuyuki , Watanabe Go , Kato Takashi , Washizu Hitoshi
Published: July 2021

MD simulation reveals the nature of water transport inside the 1D and 3D nanochannels of self-assembled ionic liquid crystal.
Characterizing dedifferentiation of thyroid cancer by integrated analysis
Authors: Luo Han , Xia Xuyang , Kim Gyeong Dae , Liu Yang , Xue Zhinan , Zhang Lingyun , Shu Yang , Yang Tian , Chen Yan , Zhang Shouyue , Chen Haining , Zhang Weihan , Li Ruicen , Tang Huairong , Dong Birong , Fu Xianghui , Cheng Wei , Zhang Wei , Yang Li , Peng Yong , Dai Lunzhi , Hu Hongbo , Jiang Yong , Gong Changyang , Hu Yiguo , Zhu Jingqiang , Li Zhihui , Caulin Carlos , Wei Tao , Park Jihwan , Xu Heng
Published: July 2021

Clinical staining and targeting CREB3L1 facilitates precise stratification and a potential treatment strategy for thyroid cancer.
Size- and composition-controlled intermetallic nanocrystals via amalgamation seeded growth
Authors: Clarysse Jasper , Moser Annina , Yarema Olesya , Wood Vanessa , Yarema Maksym
Published: July 2021

Seed amalgamation reaction unlocks a large family of intermetallic nanocrystals with excellent size and composition control.
Synthetic dysmobility screen unveils an integrated STK40-YAP-MAPK system driving cell migration
Authors: Yu Ling-Yea , Tseng Ting-Jen , Lin Hsuan-Chao , Hsu Chi-Lin , Lu Ting-Xuan , Tsai Chia-Jung , Lin Yu-Chiao , Chu I , Peng Chien-Tzu , Chen Hou-Jen , Tsai Feng-Chiao
Published: July 2021

Blocking collaborative pathways within the integrated signaling network synergistically disrupts the migration of cells.
Biomaterials with structural hierarchy and controlled 3D nanotopography guide endogenous bone regeneration
Authors: Chen Shixuan , Wang Hongjun , Mainardi Valerio Luca , Talò Giuseppe , McCarthy Alec , John Johnson V. , Teusink Matthew J. , Hong Liu , Xie Jingwei
Published: July 2021

Biomaterials without incorporating therapeutic agents and living cells effectively repair critical-sized rat cranial bone defects.
Virology Laboratory Guidelines
Authors: Kalejta Robert F.
Published: July 2021

Starting work in a virology research laboratory as a new technician, graduate student, or postdoc can be complex, intimidating, confusing, and stressful. From laboratory logistics to elemental expectations to scientific specifics, there is much to learn.
Statins act as transient type I interferon inhibitors to enable the antitumor activity of modified vaccinia Ankara viral vectors
Authors: Tenesaca Shirley , Vasquez Marcos , Alvarez Maite , Otano Itziar , Fernandez-Sendin Myriam , Di Trani Claudia Augusta , Ardaiz Nuria , Gomar Celia , Bella Angela , Aranda Fernando , Medina-Echeverz José , Melero Ignacio , Berraondo Pedro
Published: July 2021

Background

Modified vaccinia virus Ankara (MVA) are genetically engineered non-replicating viral vectors. Intratumoral administration of MVA induces a cyclic GMP-AMP synthase-mediated type I interferon (IFN) response and the production of high levels of the transgenes engineered into the viral genome such as tumor antigens to construct cancer vaccines. Although type I IFNs are essential for establishing CD8-mediated antitumor responses, this cytokine family may also give rise to immunosuppressive mechanisms.

Methods

In vitro assays were performed to evaluate the activity of simvastatin and atorvastatin on type I IFN signaling and on antigen presentation. Surface levels of IFN α/β receptor 1, endocytosis of bovine serum albumin-fluorescein 5 (6)-isothiocyanate, signal transducer and activator of transcription (STAT) phosphorylation, and real-time PCR of IFN-stimulated genes were assessed in the murine fibroblast cell line L929. In vivo experiments were performed to characterize the effect of simvastatin on the MVA-induced innate immune response and on the antitumor effect of MVA-based antitumor vaccines in B16 melanoma expressing ovalbumin (OVA) and Lewis lung carcinoma (LLC)-OVA tumor models. RNAseq analysis, depleting monoclonal antibodies, and flow cytometry were used to evaluate the MVA-mediated immune response.

Results

In this work, we identified commonly prescribed statins as potent IFNα pharmacological inhibitors due to their ability to reduce surface expression levels of IFN-α/β receptor 1 and to reduce clathrin-mediated endocytosis. Simvastatin and atorvastatin efficiently abrogated for 8 hours the transcriptomic response to IFNα and enhanced the number of dendritic cells presenting an OVA-derived peptide bound to major histocompatibility complex (MHC) class I. In vivo, intraperitoneal or intramuscular administration of simvastatin reduced the inflammatory response mediated by peritumoral administration of MVA and enhanced the antitumor activity of MVA encoding tumor-associated antigens. The synergistic antitumor effects critically depend on CD8+cells, whereas they were markedly improved by depletion of CD4+lymphocytes, T regulatory cells, or NK cells. Either MVA-OVA alone or combined with simvastatin augmented B cells, CD4+lymphocytes, CD8+lymphocytes, and tumor-specific CD8+in the tumor-draining lymph nodes. However, only the treatment combination increased the numbers of these lymphocyte populations in the tumor microenvironment and in the spleen.

Conclusion

In conclusion, blockade of IFNα functions by simvastatin markedly enhances lymphocyte infiltration and the antitumor activity of MVA, prompting a feasible drug repurposing.
Direct identification of neoantigen-specific TCRs from tumor specimens by high-throughput single-cell sequencing
Authors: Lu Yong-Chen , Zheng Zhili , Lowery Frank J , Gartner Jared J , Prickett Todd D , Robbins Paul F , Rosenberg Steven A
Published: July 2021

Background

Recognition of neoantigens by T cells plays a major role in cancer immunotherapy. Identification of neoantigen-specific T-cell receptors (TCRs) has become a critical research tool for studying T cell-mediated responses after immunotherapy. In addition, neoantigen-specific TCRs can be used to modify the specificity of T cells for T cell-based therapies targeting tumor-specific mutations. Although several techniques have been developed to identify TCR sequences, these techniques still require a significant amount of labor, making them impractical in the clinical setting.

Methods

Thanks to the availability of high-throughput single-cell sequencing, we developed a new process to isolate neoantigen-specific TCR sequences. This process included the isolation of tumor-infiltrating T cells from a tumor specimen and the stimulation of T cells by neoantigen-loaded dendritic cells, followed by single-cell sequencing for TCR and T-cell activation markers, interferon-γ and interleukin-2.

Results

In this study, potential neoantigen-specific TCRs were isolated from three melanoma and three colorectal tumor specimens. These TCRs were then synthesized and transduced into autologous T cells, followed by testing the recognition of neoantigens. A total of 28 neoantigen-specific TCRs were identified by this process. If identical TCR sequences were detected from two or more single cells, this approach was highly reliable (100%, 19 out of 19 TCRs).

Conclusion

This single-cell approach provides an efficient process to isolate antigen-specific TCRs for research and clinical applications.
Sealing the leaky pipeline: attracting and retaining women in cardiology
Authors: Cader F Aaysha , Alasnag Mirvat , Banerjee Shrilla
Published: July 2021

Multiple publications have addressed the under-representation of women in the cardiology workforce, and indeed in leadership positions and procedural subspecialities, despite gender parity among medical school graduates. The work–life balance does not appear to be the only determining factor since other specialties such as obstetrics have a adequate representation of women. Vlachadis Castleset alreport the results from their online survey of 452 female doctors (both trainees and specialists) from Australia and New Zealand, 13% of whom were women in cardiology. Female cardiologists reported working longer hours and more on-call commitments; significantly fewer women in cardiology reported a balanced life, or that cardiology was family friendly or female friendly, despite a greater earning capacity and an overwhelming majority agreeing that they were professionally challenged whilst intellectually stimulated in their jobs. Our editorial addresses the deterrents to women in cardiology seeking leadership opportunities in all areas including academic, administrative and research positions.
Progressive encephalomyelitis with rigidity and myoclonus (PERM)
Authors: Grech Neil , Caruana Galizia John Paul , Pace Adrian
Published: July 2021

Progressive encephalomyelitis with rigidity and myoclonus (PERM) is a subtype of stiff-person syndrome (formerly stiff-man syndrome). It is rare and disabling, and characterised by brainstem symptoms, muscle stiffness, breathing issues and autonomic dysfunction. We describe a 65-year-old man who presented with odynophagia together with tongue and neck swelling, followed by multiple cranial nerve palsies culminating in bilateral vocal cord paralysis with acute stridor. He subsequently developed progressive generalised hypertonia and painful limb spasms. Serum antiglycine receptor antibody was strongly positive, but antiglutamic acid decarboxylase and other antibodies relating to stiff-person syndrome were negative. We diagnosed PERM and gave intravenous corticosteroids and immunoglobulins without benefit; however, following plasma exchange he has made a sustained improvement.
Cooling–heating phase transition of the Euler–Heisenberg-AdS black hole
Authors: Meng Y. , Chen B. B. , Tang J.
Published: July 2021

We investigate the cooling–heating phase transition of the Euler–Heisenberg-AdS black hole. First, the black hole thermodynamic quantities and the state equation are reviewed. Then, we research cooling–heating phase transition and further plot the inversion and isenthalpic curves in the T–P plane. Meanwhile, we find that the inversion temperature gradually decreases with the increase of Euler–Heisenberg parameter a for the inversion curves, while this parameter has no effect in the cooling region, and the isenthalpic curves gradually move to the positive direction of X-axis with the increase of Euler–Heisenberg parameter a in the heating region. In particular, the inversion temperature and pressure of this black hole are negative, we deem that this case is caused by the vacuum polarization and the quantum electrodynamics corrections, which makes the electromagnetic energy (repulsion force) produced by the black hole shield the gravity produced by the black hole mass. In addition, this explanation has been mentioned in previous studies [M. Daniela and B. Nora, Phys. Rev. D 102, 084011 (2020); R. Ruffini, Y. B. Wu and S. S. Xue, Phys. Rev. D 88, 085004 (2013)].
Biological activity of gum Arabic-coated ferrous oxide nanoparticles
Authors: Huseen Rania Hasan , Taha Ali A. , Ali Ihab Q. , Abdulhusein Oday Mahmmod , Al-Jawad Selma M. H.
Published: July 2021

In this study, iron oxide nanoparticles (NPs) had been prepared by co-precipitation method. In order to reduce their toxicity and increase stability, prepared iron oxide was coated with gum Arabic. Gum Arabic is preferred over synthetic materials due to their non-toxicity, low cost and availability. Characterization of coated and non-coated iron oxide NPs had been performed by spectrophotometer, Fourier transfer infra-red spectrophotometer (FTIR), Zeta potential, X-ray diffraction (XRD) and field emission scanning electron microscopic (FE-SEM). The fabricated nanoparticles appeared purity and crystalline nature by XRD, with diameter average of 27.01 nm and 55.12 nm for iron oxide NPs and iron oxide NPs coated with gum Arabic, respectively. On the other hand, four biological activities of coated and non-coated iron oxide had been investigated. High removal of methylene blue pollutant dye (46%) was observed with iron oxide NPs, while removal percentage was 22.6 performed by iron oxide NPs coated with gum Arabic within 72 h. Iron oxide NPs revealed high inhibition zones of 27.5 nm and 30 mm, at 1000 [Formula: see text]g/ml, against S. aureus and E. coli, respectively, while coated iron oxide NPs with gum Arabic revealed low antibacterial activity against both examined bacteria even when used at 1000 [Formula: see text]g/ml. The hemolytic activity of prepared NPs had been determined. The hemolytic percentage was increased whenever concentrations of nanoparticles increased. Lower hemolytic percentages were 69.76 and 50.98 for iron oxide NPs and iron oxide NPs coated with gum Arabic were observed at a concentration of 250 [Formula: see text]g/ml. Finally, cytotoxic activity was estimated against MCF-7 cell line and normal cell line WRL68 by MTT assay. A decrease in MCF-7 viability to 65.1% was observed when 400 [Formula: see text]g/ml of iron oxide NPs was used, while WRL68 viability was 75.03%. Iron oxide NPs coated with gum Arabic revealed significant reduction in MCF-7 and WRL68 viability to 69.90% and 80.05%, respectively, when 400 [Formula: see text]g/ml of nanoparticles was applied.
The Recent and Predictable Future: The U.S. Posture Toward China During and After the Presidential Election Campaign
Authors: Shi Yinhong
Published: July 2021

Due to the serious perverse actions of the Trump administration in the fields of strategic rivalry, political/ideological confrontation, diplomatic exchanges and trade war between China and the United States as well as in that of global governance, Biden’s new administration is bound to make revisions somewhat and somehow. However, the current posture of the United States toward China is not only strong and enduring international structural dynamics in many aspects, but also multilateral strong and enduring domestic political and social ones. Therefore, its revision is to be necessarily quite partial and limited, and the confrontation and competition with China in some other areas will probably intensify. To a large extent, the trend of China–US relations after the US election could be influenced or even shaped by China, so China’s strategy and policy and appropriate adjustment are of great importance. China needs to take the initiative to avoid military conflicts with the United States, treating it as the essential highest common interest and the vital “common denominator” and to strive for a sort of pragmatic, focused and concrete dialogue or negotiation with the Biden administration as soon as possible after it took office.
Electrochemical Characteristics of SOFC Anodes Operated at High Fuel Utilization
Authors: Matsui Toshiaki , Fujinaga Tomoki , Ozeki Takashi , Shimizu Ritsuki , Muroyama Hiroki , Eguchi Koichi
Published: July 2021

High energy conversion efficiency in solid oxide fuel cell (SOFC) systems can be achieved by improving the fuel utilization. However, when the SOFCs are operated under high fuel utilization, the downstream part of the anode is exposed to high steam concentration and hence high P(O2) atmospheres, and this has a negative impact on the stability of Ni-based cermet anodes. At this stage, no reports dealt with the degradation phenomena of the anode under such severe conditions. In this study, we aimed to clarify degradation phenomena at the downstream part of practical cells operated at high fuel utilizations by using bottom cells. Fuel gases that simulated severe conditions were supplied to single cells. The change in electrochemical properties was monitored during discharge operation, and the microstructural evolution of the anode was quantitatively analyzed by the FIB–SEM technique.
Electrochemical Reduction of H2O and CO2 Using Anode Supported SDC Cells
Authors: Zhang Xinge , Fahlman Jason , Robertson Mark , Yao Peter
Published: July 2021

Solid oxide electrolysis cells (SOECs) have emerged as an attractive approach for electrochemical reduction of CO2 and/or H2O to high energy molecules, such as CO and/or H2, and demonstrated high faradic efficiency (good selectivity), high energy efficiency (low cell voltage), and high operating current density (high productivity). Conventionally SOECs based on YSZ as electrolyte material operate approximately 800oC in order to achieve a practical cell performance and to mitigate carbon deposition. However, high operating temperature leads to high cost and fast degradation of the SOEC system. Meanwhile, it becomes impossible to produce chemical fuels, such as methane, from the co-electrolysis of CO2 and H2O through in situ methanation.

In this contribution, we studied electrochemical reduction of H2O and CO2 at reduced temperatures using anode supported SDC cells, with Ni-SDC anode and SSC cathode of effective area of 2 cm2, and the SDC electrolyte about 10-15 um in thickness. We found that the SDC cell performance (Cell#1) under electrochemical reduction of H2O reaches 0.5 A/cm2 at 1.15 V at 500oC with inlet gas composition of 50% H2O + 50% H2, at a flow rate of 100 ml/min/cm2. We repeated electrochemical reduction of H2O test using another SDC cell (Cell#2), and also conducted electrochemical reduction of CO2 at reduced temperatures. It was noticed that the cell performance under electrochemical reduction of H2O showed slightly better than, but quite similar to, that under CO2 reduction. The SDC cell (Cell#2) performance under electrochemical reduction of CO2 showed 0.5 A/cm2 at 1.17 V at 500oC with inlet gas composition of 80% CO2 + 20% H2, at a flow rate of 10 ml/min. This cell also showed no degradation during a short term (72hr) stability test under the CO2 reduction condition.

Interestingly, under the tested conditions, SDC cells showed much better performance under the electrolysis cell (EC) mode than under the fuel cell (FC) mode. For example, at 500 oC, with 100mlpm H2-100mlpm H2O, the cell OCV is about 0.844V, the cell only reached 0.25A/cm2 at 0.4V under the FC mode, while under the EC mode it reached 1.26V at 1 A/cm2, which is approximately 4 times higher with the same polarization value of the cell voltage in comparison to the FC mode. The cause for the difference are investigated.
Redox Stability of Tubular Solid Oxide Cell Using LaGaO3 Electrolyte Film Prepared by Dip-Coating
Authors: Tan Zhe , Ishihara Tatsumi
Published: July 2021

Reversible operation of SOFC is now important subjects from energy storage of renewable electric power from solar or wind power. At present, planer type cell design is widely used for this purpose, however, because of tight gas sealing, tubular type cell design is more suitable. In this study, tubular solid oxide cell using La0.9Sr0.1Ga0.8Mg0.2O3−δ (LSGM) thin electrolyte film was prepared by dip-coating and co-sintering process.

NiO-YSZ porous substrate with 10 mm diameter and 30 mm length was used for preparation of the cell. For preventing reaction between LSGM and NiO, TiO2-Ce0.6La0.4O2/Ce0.6Mn0.3Fe0.1O2 was used for buffer layer. The cyclic operation of fuel cell and electrolysis mode was measured for investigating the stability of the prepared tubular cell at an intermediate temperature of 600℃ under the fuel of 20%steam-30%H2 in Ar. After 100 redox cycles under the applied current density of ±100 mA cm-2 , OCV was almost the same with the initial value before measurement. The terminal potential in SOFC operation became slightly lower and unstable with increasing cycle number, however, degradation in power density is not significantly observed. The cell also presents a relative stable performance in the electrolysis mode and it seems to be more active to SOEC than that to SOFC. From measurement of internal resistance, degradation may be related with the increased overpotential of anode. Therefore, aggregation and reoxidation of Ni in Ni-YSZ substrate is expected.

In order to further increase performance of the cell, effects of Ce infiltration into NiO-YSZ contributes and it was found that the power density and electrolysis performance was much increased by the decreased internal resistance. The redox stability of NiO-YSZ-CeO2 cell was also measured and it also presents a stable redox performance after 100 times cycles by infiltration of CeO2.
Analysis of 3D Printed Ceramic Nanocomposite Fuel Cells
Authors: Asghar Muhammad Imran , Lund Peter D.
Published: July 2021

We have reported our synthesized ceramic nanocomposite materials with remarkably high ionic conductivity (0.5 S/cm at 550oC). The fuel cells utilizing this promising ceramic nanocomposite electrolyte produced a high performance of 1.1 W/cm2 at 550oC. The performance of the cell is limited due to the thickness of the cell (600 µm) and especially the electrolyte layer (300 µm). We envision that our fuel cells utilizing promising nanocomposite materials can reach performances >2 W/cm2 at 550oC if their thickness can be reduced to less than 200 µm. Unfortunately, with the conventional pressing method used for our cells manufacturing, the thickness of the cells cannot be reduced precisely. Moreover, this fabrication method is not suitable for large-scale upscaling of the technology. The printing methods, especially digital printing techniques including 3D and inkjet printing, enable the fabrication of thin ceramic fuel cell with better controllability. In our preliminary experiments, we successfully printed our high-performance nanocomposite electrolyte with a 3D printer. The printed electrolyte shows an excellent performance of 0.32 ± 0.04 S/cm at 550oC. The key challenges related to the 3D printing of ceramic fuel cell is highlighted in the work. Furthermore, in addition to our research on conventional 3-layer cell structure, our research on novel 3D printed single-layer cells will be presented.

Acknowledgement: This work is supported by Academy of Finland (Grant No. 13329016). Dr. Asghar thanks Academy of Finland (Grant No. 13322738) and the Hubei overseas Talent 100 program for their support.

References

[1] M. I. Asghar, M. Heikkilä and P. D. Lund, Materials Today Energy, 5 (2017) 338.

[2] M. I. Asghar, S. Jouttijärvi and P. D. Lund, International Journal of Hydrogen energy, 43 (2018) 12892.

[3] M. I. Asghar, S. Jouttijärvi and P. D. Lund, International Journal of Hydrogen energy, 43 (2018) 12797.

[4] M. I. Asghar, S. Jouttijärvi, R. Jokiranta, A. Valtavirta and P. D. Lund, Nanoenergy, 53 (2018) 391.

[5] M. I. Asghar, S. Jouttijärvi, R. Jokiranta, E. Hochreiner and P. D. Lund, International Journal of Hydrogen Energy, (2019).
Preparation, Evaluation, and Application of SUS430/441 Interconnect with Mn-Co Coating in Solid Oxide Fuel Cells
Authors: Cui Tonghui , Liang Fuyuan , Sun Ruiting , Wu Junwei , Han Minfang , Sun Kaihua , Liu Yang
Published: July 2021

Yttria-stabilized zirconia (YSZ) - gadolinia doped ceria (GDC) is the most commonly used bilayer electrolyte, YSZ can protect GDC from being chemically reduced and GDC can prevent YSZ from reacting with cathode. To promote the performance and stability of large-size anode-supported solid oxide fuel cell (SOFC) based on LSCF-GDC bilayer electrolyte, three types of cells were designed and manufactured with different GDC thickness and sintering temperature. Then electrochemical characterization of the cells was carried out, showed that the cell with GDC thickness of 10μm and sintering temperature of 1330℃ had the best performance. The open current voltage (OCV) was 1.15V and the peak power density reached 0.45W/cm2 when operating at 720 ℃. Furthermore, the electrochemical impedance spectroscopy (EIS) was analyzed by the distribution of relaxation times (DRT) method, indicated that charge-transfer reaction at anode three-phase boundary mainly dominated the performance degradation. The results obtained can provide guidance for the optimization of performance and stability.
Sr Surface Segregation; Implications for Oxygen Electrode Behavior and Routes to Mitigate Impact
Authors: Tripković Đorđije , Küngas Rainer , Mogensen Mogens Bjerg , Yildiz Bilge , Hendriksen Peter Vang
Published: July 2021

The activation energy of the oxygen evolution/oxygen reduction process at perovskite type oxygen electrode materials is slightly higher than that of oxygen transport in the classical electrolyte materials, and also of that of the steam-splitting/hydrogen oxidation process at the fuel electrode. Today at 750 oC – 800 oC state of the art oxygen electrodes do not limit overall SOEC/SOFC performance, but when pushing the operation temperature lower, towards 600 oC the oxygen electrode can become limiting. Hence, there is still a need to develop high performing and importantly, durable, oxygen electrodes.

One mechanism that has been reported to reduce oxygen exchange rates at Sr-containing perovskite type electrode materials is Sr segregation to the surface. This has especially been studied and observed on model systems like thin films [1, 2] and bulk materials [3, 4]. A surface enrichment in Sr will potentially make an electrode more vulnerable to degradation by reaction with gas-phase impurities like CO2 and Sulphur-species, but also to Cr-poisoning. Hence, it is important to study what drives such surface enrichment and how to mitigate its consequences.

We have studied this in some detail on La0.6Sr0.4FeO3 both on thin films [2] and on bulk samples [4]. Interestingly, on the thin film model system, one can to some extent alleviate the consequences of the enrichment by leaching away excess Sr [1,2]. On the bulk samples, we have found that the oxygen exchange kinetics decrease with aging at low temperature (650 oC), but that the samples can be rejuvenated by a short high temperature treatment [4].

In this contribution, we shall present the relation between the oxygen exchange rates measured on La0.6Sr0.4FeO3 surfaces and the chemistry of the surface. It turns out, that Sr enrichment to the surface occurs very fast and the “rejuvenation” treatment does not affect the Sr content at the surface, but rather in which phase/environment the Sr is found.

We shall further discuss the implications of the learnings on above presented model-type-systems to the technical level, where often the materials are applied in form of composites.

[1] Z. Cai, M. Kubicek, J. Fleig and B. Yildiz, Chem. Mater., 2012, 24, 1116–1127

[2] Tripković, D., Küngas, R., Mogensen, M. B. & Hendriksen, P. V., 2020, Physical Chemistry Chemical Physics. 22, 27, p. 15418-15426

[3] Edith Bucher, Werner Sitte, Solid State Ionics
192 (2011) 480–482.

[4] Đ. Tripković, R. Küngas, M. B. Mogensen and P. V. Hendriksen, J. Mater. Chem. A, 2019, 7, 11782–11791.

Figure 1
Conducting Property and Performance Evaluation of LNF as Cathode Current Contact Layer in Solid Oxide Fuel Cell
Authors: Lyu Qiuqiu , Wang Yu , Zhu Tenglong , Sun Kaihua , Sun Zaihong , Bu Yunfei , Zhong Qin , Han Minfang
Published: July 2021

Electrical performance, durability and degradations are challenging issues for Solid Oxide Fuel Cell (SOFC) commercialization. Ce0.9Gd0.1O2-δ (GDC) and La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) are current gold material system in SOFC, which mainly works as barrier layer and cathode, respectively. However, the porous GDC barrier layer and vulnerable cathode/electrolyte interface often leads to high ohmic resistances and fast degradations. Herein, we develop and report a novel approach for barrier layer and cathode modifications, using cost-competitive and scalable hydrothermal reaction.

Results show that, the as-sintered porous GDC barrier layer is filled up with in-situly grown Ceria based nano particles during hydrothermal reaction, yielding improved density and sintering-active surface, simultaneously. After co-sintered with cathode, the cell obtains optimized cathode/barrier layer interface, exhibiting decreased ohmic and cathode polarization resistances with higher electrical performance and less degradation.

On the other aspect, the Ceria based nano particles are also observed in-situly precipitated on LSCF powder surface during hydrothermal reaction, forming dual-phase LSCF@GDC cathode, which also yields decreased ohmic and polarization resistance than pristine LSCF.

Above results suggest that hydrothermal modifications are effective for barrier layer and cathode/electrolyte interface optimizations. Thus, the improved oxygen ion transfer and interface contact are beneficial for SOFC electrical performance and long-term operation. Furthermore, this hydrothermal modification is applicable in many other surface and interface optimizations.
Electrochemical Performance of New Bilayer Oxygen Electrode for Reversible Solid Oxide Cells
Authors: Huang Kevin , Wen Yeting
Published: July 2021

High-temperature solid oxide cells (HT-SOCs) have innate advantages over their low-temperature counterparts in efficiency and production rate since part of the chemical energy in the products comes directly from the heat and the operating current density (proportional to H2 production rate) is high. However, a major obstacle for HT-SOCs to be commercially viable is the poor long-term stability, particularly at high current densities. The rudimentary cause for the instability is believed to result from the mechanical delamination of oxygen electrode (OE) from the electrolyte due to the mismatch in oxygen evolution reaction (OER) rate and applied current density, which results in high oxygen partial pressure at the interface. Therefore, a way to minimize the delamination is to enhance OE’s OER rate (i.e. reduce OER area-specific-resistance, ASR) to match the high applied current density. In this presentation, we show the employment of three-electrode symmetrical cell method to exclusively characterize the OER’s ASR of bilayer OE under applied current density at high temperatures. The results explicitly show that the bilayer OE with low OER’s ASR outperforms the baseline single layer OE (LSCF-GDC) in long-term stability at high current density of 1 A/cm2 and 700oC; the former can last ~1000 hrs under a constant 1A/cm2 current before observing performance degradation and delamination, whereas the latter shows significant performance degradation and delamination even after 100 hrs. We conclude that the bilayer OE exhibits a better chemical, thermal, mechanical, and more importantly electrochemical stability over the benchmark single layer LSCG-GDC OE.
Sizing Design and Simulation of an SOFC Propulsion System for Unmanned Aerial Vehicles
Authors: Tong Xin , Wang Yuqing , Shi Yixiang
Published: July 2021

The short flight endurance is one of the key obstacles for the application of unmanned aerial vehicles (UAVs). Appling the fuel cells as the propulsion system of UAVs instead of batteries can increase the energy density and further lead to a longer cruise duration. Compared to other kinds of fuel cells, the solid oxide fuel cell (SOFC) is advantageous for its ability to use hydrocarbon fuels with a much higher energy storage density than hydrogen. In this paper, a SOFC propulsion system is sized and designed for UAV applications. A system model was developed, including a SOFC stack, a catalytic partial oxidation (CPOx) reformer, an after burner, heat exchangers, lithium batteries, etc. The design parameters of the SOFC stack and other components were selected to meet the power and energy demand of the UAV. The power allocation between the SOFC and energy storage components was further studied. The model is proved to be a useful tool for the design and simulation of the UAV-SOFC systems.