Number Of Projects Research Articles

Radiation Shielding Features of Glass Fiber Reinforced Cast Polyamide Using Phy-X/PSD and SRIM Software

The utilization of various materials for their nuclear radiation shielding properties has been the subject of a growing number of research and development projects. In this study, the radiation shielding characteristics of E-glass fiber reinforced cast polyamide were evaluated. E-glass is a form of glass fiber frequently utilized as a reinforcement in various composite materials to provide more durability, stiffness, and strength. Samples S1-S7 were defined according to various compositions of E-glass fiber contents (SiO2, Al2O3, B2O3, MgO, CaO, Na2O and K2O) and cast polyamide (C12H22N2O2). Within the energy range 0.015-15 MeV, the shielding parameters: Linear attenuation coefficient (LAC), mass attenuation coefficient (MAC), half and tenth value layers (HVL, TVL), mean free path (mfp), effective atomic number (Zeff), atomic and electronic cross sections (ACS, ECS), fast neutron removal cross-section (FNRCS) and exposure buildup factor (EBF) were analyzed. E-glass fiber reinforced cast polyamide S7 (70% glass fiber content) exhibited higher values of LAC, MAC and Zeff and lower values of HVL, TVL, and mfp proving it to be a better radiation shielding material among the samples. An abrupt reduction in values of Zeff was discerned within the photoelectric absorption-dominant region, contrasted with a stable trend within the Compton scattering-dominant region, and a marginal elevation was noted in the pair production region. The maximum and minimum values of FNRCS were observed for samples S1 (10% glass fiber content) and S5 (50% glass fiber content) respectively. Hence, S1 would be the most effective material in fast neutron shielding. At 35 mfp penetration depth, the minimum EBF values belonged to S7 in lower and intermediate regions (0.015-3 MeV) whereas S1 showed the minimum values at higher energy regions (4-15 MeV). Furthermore, the mass stopping power (MSP) and projected range (PR) of the samples for alpha and proton particles were determined using SRIM-2008 codes. S7 exhibited better shielding features for alpha and proton particles with lower values of mass stopping power and projected range. The reinforcement of glass fiber in the cast polyamide has been noticed to have a significant impact on the shielding performance of polymer composites.

Controlled Surface Functionalization Using Aryldiazonium Salts for the Development of Aptasensing Platforms

It is well known that both the aptamer surface density and surface chemistry can have a strong influence on the analytical performance of aptasensors based on target-induced conformational changes1. In this context, we report here an improved protocol for obtaining aptasensing platforms which allows fine-tuning the DNA aptamer surface coverage. First, glassy carbon substrates were functionalized with ethynylphenyl groups through the electrochemical reduction of silyl-protected ethynylphenyl diazonium tetrafluoroborates followed by deprotection with tetrabutylammonium fluoride2. The successful removal of the protecting groups (triisopropylsilyl-, triphenylsilyl- and tris(biphen-4-yl)silyl-) was confirmed by X-ray photoelectron spectroscopy and cyclic voltammetry in the presence of Fe(CN)6 3-/4- as soluble redox probe. Following “click” post-modification with suitable derivatization reagents, the surface coverage with ethynylphenyl groups was assessed using complementary techniques such as XPS, cyclic voltammetry and chronocoulometry. For example, the F/C surface ratio of substrates derivatized with 1-(2,2,2-trifluoroethoxy)-6-azidohexane provided an indication of the functionalization degree, and the integration of Fc/Fc+ voltammetric peaks for substrates modified with N-(6-azidohexyl)ferrocenecarboxamide allowed a quantitative determination of the surface coverage. Both techniques showed a good correlation between the protective group size and the surface coverage with alkyne groups. Likewise, we observed a similar trend for substrates derivatized with azide-modified oligonucleotides, where the surface packing density was determined based on the chronocoulometric response of Ru(NH3)6 3+, a cationic redox probe which binds with the negatively charged phosphate groups from the oligonucleotide backbone. As proof of concept, we further developed an electrochemical molecular beacon aptasensor employing a ferrocene-labeled quinine aptamer. We demonstrate that the aptamer surface density, and ultimately the analytical performance of molecular beacon aptasensors, can be effectively fine-tuned by employing silyl protecting groups of different sizes.Acknowledgements This work was supported by a grant from the Romanian Ministry of Education and Research, CNCS-UEFISCDI, project number PN-III-P4-ID-PCE-2020-2474, within PNCDI III. References Onaş, A. M., Dascălu, C., Raicopol, M. D. & Pilan, L. Critical Design Factors for Electrochemical Aptasensors Based on Target-Induced Conformational Changes: The Case of Small-Molecule Targets. Biosensors 12, (2022).Leroux, Y. R., Fei, H., Noël, J.-M. M., Roux, C. & Hapiot, P. Efficient covalent modification of a carbon surface: Use of a silyl protecting group to form an active monolayer. J. Am. Chem. Soc. 132, 14039–14041 (2010).

Dual-Function Sensing Platform for Hg2+ Based on a Redox-Active Thiosemicarbazone Receptor

Recently, our group developed a platform for adsorptive stripping voltammetric analysis of heavy metals based on electrodes modified with “clickable” thiosemicarbazone ligands, achieving detection limits for Hg2+ in the nM range1. Here, we present an extension of our previous results towards obtaining an innovative, dual-function sensing platform suitable for both rapid screening and accurate quantitation of mercury. For this purpose, we designed a novel ferrocene-based redox-active thiosemicarbazone receptor having an intramolecular signalling pathway between the binding site and redox-active center, a prerequisite for obtaining efficient redox-active receptors3. The metalloligand, which also contains an azido functional group, was synthesized by reacting 4-(6-azidohexyl)-3-thiosemicarbazide1 with ferrocenealdehyde. The binding properties of the ligand towards several heavy metal ions (Cd2+, Cu2+, Hg2+, Ni2+, Pb2+, Zn2+) were evaluated by UV-VIS spectroscopy, ESI-MS and cyclic voltammetry. Notably, the voltammograms recorded in the presence of sub-stoechiometric amounts of Hg2+ displayed a “two-wave” behavior4 for the Fc/Fc+ redox couple (ΔEp~100 mV), suggesting a high binding constant for this particular ion. Next, modified electrodes were prepared by grafting glassy carbon substrates with triisopropylsilyl-protected phenylethynyl groups through the electrochemical reduction of the corresponding diazonium salt5, followed by deprotection of the alkyne groups and „click” immobilization of the thiosemicarbazone receptor. The electrode surface functionalization was further assessed using electrochemical techniques and X-ray photoelectron spectroscopy, and the complexation behavior of the modified electrodes in the presence of heavy metal ions was investigated using Osteryoung square-wave voltammetry6. As expected, the Fc/Fc+ couple from the surface-immobilized ligand displayed the same voltammetric behavior as in solution, and the appearance of a new voltammetric wave shifted by ~100 mV allows the rapid qualitative screening of Hg2+. Furthermore, the modified electrodes were employed for the accurate quantitation of Hg2+ ions using the accumulation at open circuit-anodic stripping voltammetry technique, achieving a LOD of 5.0 nM. Finally, we demonstrate that electrodes modified with the thiosemicarbazone metalloligand have a very good reproducibility, reusability and stability. Acknowledgements This work was supported by a grant of the Ministry of Research, Innovation and Digitization, CNCS-UEFISCDI, project number PN-III-P1-1.1-TE-2021-1163, within PNCDI III.

Electrochemistry and Electronic Structure of the Deuterium-Grown Boron-Doped Diamond Interfaces

Integration of the first principles quantum mechanical simulations with electrochemistry represents a difficult research area due to the complexity and large size of real systems and computational limitations. On the one hand it is highly desirable to be able to predict electrochemical properties of materials and systems from simulations to limit the money expenditure for experimental work and accelerate applications [1]. On the other hand, utilization of ab-initio simulations to understand the experimentally observed phenomena is also required to embed them into a solid theoretical framework.To fulfill this task, several multiscale approaches are used with the density functional theory (DFT) being fundamental tool for investigation of electronic structure. DFT results can be further extended to build forcefields used in molecular dynamics (MD) [2] for larger scale simulations and non-equillibrium Green's functions for investigations of electronics and spintronics of nanodevices [3]. Semiconductor electrochemistry is one of the most important areas to explore this experiment-theory interface because of the necessity to develop new materials for photovoltaics, photoelectrochemistry, energy storage and conversion. The purpose of the following talk is to show the power of this paradigm by elucidation of the deuterium-grown boron doped diamond (BDD-D) material [4].A brief introduction to the material synthesis, chemical and physical properties is provided exploiting the synchrotron data of X-Ray absorption spectroscopy and X-Ray photoelectron spectroscopy. Then, a strong emphasis is put into merging the (photo)electrochemical data with the first principle results for better understanding of charge transfer phenomena in the nanoscale. Specifically, DFT calculations of projected local density of states clearly show the presence of highly occupied surface states on the (111) plane of BDD-D in contrast to its standard hydrogen-grown counterpart (BDD-H). The resulting surface states are capable of photocurrent generation in the visible light, which is strongly magnified in BDD-D. Moreover, photoelectrochemical measurements evidenced that photocurrents can be positive or negative depending on the bias - despite BDD being a p-type semiconductor. These confirm a profound role of surface states in the semiconductor electrochemistry and capability of photoinduced charge transfer in the modified materials. The proposed picture shines some new light on the commonly established paradigm of band bending as the key factor driving surface properties of the nanodiamond surfaces [5]. Figure. SEM images of a) BDD@D and b) BDD@H; c) grain size distribution among two samples; d) XRD patterns of the diamond films deposited in the D2/CH4 and H2/CH4 gas mixtures. Reflections at 2θ around 44°, 75°, and 91° correspond to the (111), (220), and (311) diamond lattice planes, respectively. Doubling of the reflections is related to the presence of Kα1 and Kα2 wavelengths in the X-ray radiation [4]. Acknowledgements: M.S., M.B., and M.F. thank Helmholtz-Zentrum Berlin (HZB) for the allocation of synchrotron radiation beamtime at HZB (Germany). M.S. gratefully acknowledges the financial support of these studies fromthe Gdansk University of Technology through the DEC-02/2021/IDUB/ II.1/AMERICIUM grant under the Americium – “Excellence Initiative – Research University” program. R.B. acknowledges the funding from the National Science Centre, Poland under the OPUS call in the Weave programme (Project number: 2021/43/I/ST7/03205).

Deciphering the True FEC Reduction Mechanism and Its Implications to the Understanding of the SEI in Li-Ion Batteries

The main challenges in rechargeable batteries, especially when aiming for high energy density, arise from the limited electrochemical stability window of current state-of-the-art electrolytes. Negative electrode active materials, such as silicon, tin oxide and others, whose capacity is many times higher than that of graphite, often exhibit large volume expansion upon lithiation and therefore the SEI formed on their surface is unstable. The most popular strategy for improving their cycling stability is the use of electrolyte additives that are reduced at potentials more positive than the electrolyte solvents. Their decomposition products are incorporated in the SEI, leading to a more stable electrode/electrolyte interface.One of the most-investigated electrolyte additives is fluoroethylene carbonate (FEC), because it has been shown to lead to a significant performance enhancement of Si- and Sn-based anodes. Many reaction pathways have been proposed, however there is currently no agreement on the exact type of chemical compounds constituting the decomposition products, nor on the exact mechanism for FEC decomposition. To address these questions, we conducted a systematic study that tracked the morphological and chemical changes during electrochemical decomposition of FEC. We have found that despite FEC often being referred as a “film-forming” additive, the first stage of its decomposition leads instead to the formation of spherical particles, consisting mainly of lithium fluoride (see figure below);1 only later a carbonate-rich film covers the entire electrode, covering as well the LiF-rich spheres. This phenomenon has been overlooked before likely due to very simple reason, disclosed in our contribution.A detailed investigation using XPEEM—a surface-sensitive analytical technique with high lateral resolution—as a function of electrolyte composition shows that fluorine in the later-formed carbonate film comes from the electrolyte salt, while all fluorine from FEC decomposition resides in the spherical particles, formed upon FEC reduction. In addition, we have found that the size and amount of particles strongly depend on the cell medium, where electrolytes with higher dielectric constant lead to larger particle size, as does the presence of the high-capacity electroactive materials in the electrode, both contributing to the final properties of FEC-derived SEI. The results of this study provide a deeper understanding of how fluorine-containing additives work and enables tuning of the SEI properties to the desired morphological and chemical outcome by using the laws of simple crystal-growth theory by adjusting the inter-cell environment.This work demonstrates that, with the right analytical tools, the true nature of the even seemingly very-well studied compounds can be revealed and a full understanding of their decomposition mechanisms can be clarified. Acknowledgement This research was supported by InnoSuisse (Project number 18254.2) References Y. Surace, D. Leanza, M. Mirolo, Ł. Kondracki, C.A.F. Vaz, M. El Kazzi, P. Novák, S. Trabesinger, Energy Storage Materials 2022, 44, 156-167. Figure 1

Plasma-Enhanced Atomic Layer Deposition of Lithium Nickel Oxide Thin Film Model Systems

The main bottleneck in the development of the next generation of Li-ion batteries with higher energy densities, as demanded for long-range electrical mobility, is the lack of understanding and control of the reactions at the electrode-electrolyte interfaces. Reactions at the cathode side cause rapid capacity loss during cycling and represent a major issue for batteries with high-voltage cathodes, which are crucial in reaching the required energy densities. Promising candidates for use in next generation of batteries are Ni-rich Li(Ni1-x-yMnxCoy)O2 (NMC) cathodes, which show high capacity, high potential, and contribute to address the geopolitical issue of decreasing the Co content in the cathode. Ni-rich NMCs exhibit similar electrochemical properties as pure LiNiO2 and therefore LiNiO2 thin films can be used as model systems to gain fundamental understanding of the interfacial processes that hinder the large-scale implementation of Ni-rich NMCs. Atomic layer deposition (ALD) is a suitable technique to fabricate these model systems, as it gives precise control over film thickness, uniformity, chemical composition, and crystal orientation.Previous work on LiNiO2 by ALD is not extensively reported in literature. Moreover, films grown by a supercycle process, in which two ALD subcycles are alternated, suffered from a low Ni at.% and a large C content because of precursor ligand residues, and films fabricated using a complex multilayered approach showed severe Si contamination from the Li precursor [1]. In this contribution we report on ALD lithium nickel oxide (LNO) thin films with stoichiometries close to LiNiO2 and low levels of contaminants.The ALD process is based on lithium hexamethyldisilazide (LiHMDS) and nickel bis(N,N’-di-tert-butylacetamidinate) (Ni(tBu-MeAMD)2) as precursors and O2 plasma as co-reactant. 1 ALD cycle of Li2O is combined with x cycles of NiO using a supercycle approach. In this contribution we explore the relation between the Ni/Li cycle ratio x and material properties of the LNO films.The growth of the LNO films is monitored by means of in-situ spectroscopic ellipsometry. The ellipsometric data of films with a high Ni/Li cycle ratio are fitted with a general oscillator model used for NiO films, while a Cauchy model was adopted in case of a low Ni/Li cycle ratio and Li2O films. The growth per supercycle (GPSC) of LNO shows an intermixing effect, as it does not follow the linear trend calculated from the growth per cycle (GPC) values of the individual Li2O and NiO ALD processes, which are 1.0 Å/cycle and 0.34 Å/cycle respectively.XPS surface measurements show that the Ni/Li atomic ratio is tuned from 0 to 10 as function of the Ni/Li cycle ratio x. Low levels of Si and N contamination, below 4% and 2% respectively, are observed. A shift of the main peak in the Ni 2p3/2 spectrum to higher binding energies indicates a shift in oxidation state from Ni2+ to Ni3+ as decreases [2]. According to surface measurements, the LNO film with x=5 shows a stoichiometry close to LiNiO2, but depth profile measurements indicate that the Ni at.% is significantly higher in the bulk than on the surface of the films, most certainly attributed to the formation of a Li2CO3 surface layer upon air exposure. Li2CO3 is also present in the bulk of the LNO films, but the bulk C at.% stays below 4%.These results show that we can use ALD to fabricate a high-voltage cathode model system, which we plan to characterize in-situ and post-mortem in combination with both liquid and solid electrolytes to study the cathode-electrolyte interface.[1] Maximov et al., Energies, 13 (2020) 2345[2] Fu et al., Applied Surface Science 441 (2018) 1048 This work is part of the ‘BatteryNL – Next Generation Batteries based on Understanding Materials Interfaces’ project (with project number NWA.1389.20.089) of the NWA research programme ‘Research on Routes by Consortia (ORC)’ funded by the Dutch Research Council (NWO). Figure:(a) The GPSC of LNO ALD process shows an intermixing effect when comparing the experimental results with the expected GPSC based on the two processes (b) Ni 2p3/2 XPS spectrum for different Ni/Li cycle ratios x. A shift to higher binding energies is observed with decreasing x, indicating a shift from Ni2+ to Ni3+. (c) XPS surface measurements of LNO films show low levels of contaminants and a Ni/Li atomic ratio varying with the Ni/Li cycle ratio. (d) Depth profile of LNO with x=5 shows an increased Ni at.% and a low C at.% in the bulk of the film. Figure 1

Elevating Energy Density in Li-Ion Batteries through Electrospun Nanotubular Titania-Polymer Interfaces

The introduction of new anode materials holds the potential to address critical safety concerns associated with current commercialized options in Li-ion batteries. Graphite, while widely used, poses challenges due to its low charging potential, which contributes to the growth of dendrites and safety risks. In contrast, titania-based materials present an appealing solution. Their higher operational potential not only curbs dendrite formation but also prevents the formation of a thick solid electrolyte interface (SEI). Furthermore, the limited volume expansion during lithiation significantly enhances their safety profile, differentiating them from graphite-based anodes such as those incorporating silicon.In this new study, titania-based nanotubular structures were created for high-energy Li-ion batteries using a novel electrospinning technique. Titania-based nanotubes were synthesized, modified for optimal charge transfer, and combined with a self-standing electrode through electrospinning with PVDF. The effects of various thermal treatment conditions on Li-ion diffusion were explored using electrochemical methods. The best charge transfer kinetics were observed in the sample treated for 10 hours. After optimizing the electrospinning process, a fully embedded nanotube fibrous structure was achieved, confirmed by electron microscopy. The use of a polymeric network removed the need for metallic current collectors, boosting energy density by 14%. These electrospun electrodes show great promise for high-energy applications.This work was supported by the M-era.Net 2019 call project “LiBASED Li-ion BAttery-SupErcapacitor Hybrid Device”. The research was co-funded by the Turkish Scientific and Technological Research Council (TUBITAK) with project number 119N758.

Atomic Layer Etching of Al2O3 Using F Radical and Al Precursors: Surface Reaction and Reaction Mechanism Study

In order to overcome the miniaturization of semiconductor devices, devices with a three-dimensional (3D) structure, such as FinFET and 3D vertical NAND devices, were introduced. The manufacturing of 3D devices requires both anisotropic etching in the vertical direction and isotropic etching in the horizontal direction. Therefore, a new technology with atomic-level precision is required for isotropic etching, which is dependent on wet etching. It is the thermal atomic layer etching (ALE) process that meets these requirements. Since the first report in 2016, the thermal ALE processes by alternating exposures to HF vapor and a metal precursor have been reported for various thin films. However, HF has issues with safety and corrosion. Recently, ALE processes using F radicals produced by inductively coupled plasma (ICP) of SF6 or NF3 have been reported [1,2]. However, the study on the reaction mechanism of F radicals is lacking. In this study, the surface reaction was studied for the modification and removal steps by NF3 remote plasma and Al precursors. We used quartz crystal microbalance (QCM) to measure the mass change during the ALE process and X-ray photoelectron spectroscopy (XPS) to analyze the composition of the modified layer. The mechanism of ALE using F radical was different from that using HF, due to the absence of H atoms. Density functional theory (DFT) simulation shows that amorphous carbon or fluorocarbon layer can be formed during the ALE by F radicals. Al precursor with fewer organic ligands was beneficial to suppress the formation of a carbon-containing surface layer. Acknowledgments This research was supported by the MOTIE (Ministry of Trade, Industry & Energy (project number 20012588) and KSRC (Korea Semiconductor Research Consortium) support program for the development of the future semiconductor device.

(Poster Award Winner 2) Solvation Effects in Electrochemical Double Layers and Static Simulations

Batteries play a key role in future sustainable energy networks. Modelling these electro-chemical systems accurately provides a path to improved battery chemistries [1]. In recent years, research has identified highly concentrated electrolytes as promising constituents for battery cells with high energy density [2]. These are, however, complex systems, where the bulk electrolyte concentration and external electric potential significantly influences the electrochemical double layer (EDL) structure. It is challenging to model the behaviour of highly concentrated electrolytes near a charged surface.Here, we present a continuum transport theory for these materials, which incorporates solvation effects. The model is built up from the second law of thermodynamics by enforcing positive entropy production. By analysing contributions to entropy production, we can establish the free energy of the electrolyte system, which in turn constitutes the basic equations of the transport theory [3,4]. Our continuum model can describe both static and dynamic systems of highly concentrated electrolytes. To analyse the EDL, static simulations have proven effective due to their very low computation cost. Using this method, we are able to achieve concentration profiles at EDL length scales, when adding nonlocal contributions [4] even oscillatory behaviour can be recreated.Solvation is a key effect to consider when modelling reactions at the electrode surface or intercalation. The desolvation at the electrode surface constitutes an energy barrier, which must be overcome. Previous solvation models [5] use a static ion-solvent coordination number, therefore the stripping of the solvation shell in the double layer cannot be described. We address this concept by incorporating local solvation in our model, enabling a description of the electric forces desolvating ions in the EDL.Solvation is added to the free energy of the system by modifying the statistics which determine the entropic contribution. Additionally, we include a term to represent the ion-solvent interaction energy. Thus, two novel parameters are used to define the interaction – the maximum number of solvent molecules binding to a single ion, and the binding energy.We supplement our analytic discussion by numerical double layer simulations of an electrolyte consisting of an IL with a solvent, neutral or charged. Our results capture the relationship of ion-solvent binding energy and the desolvation potential. We can extract qualitative results down to a molecular scale from our model, allowing us to predict coarse grained behaviour of MD-simulations. By estimating the solvent coordination number at the electrode surface, it is possible to obtain a desolvation energy barrier.Figure: a ternary EDL for two different values of the binding energy, showing a nearly complete desolvation at the electrode for the smaller binding energyThis work was funded in the project POLiS by the Deutsche Forschungsgemeinschaft (DFG) under Germany´s Excellence Strategy – EXC 2154 – Project number 390874152.Literature: Armand, M.; Tarascon, J.-M. Nature 2008 451, 652.Giffin, G.A., Nat Commun 2022 13, 5250.Schammer, M. et al. J. Electrochem. Soc. 2021, 168, 026511.Schammer, M. et al. J. Phys. Chem. B2022, 126, 14, 2761–2776.Dreyer, W. et al. Electrochem. Comm. 2014, 43, 75-78. Figure 1

Scalable Synthesis of Stable Electrocatalyst for Oxygen Reduction Reaction

Carbon-based materials have been widely recognized as support material of choice for the oxygen reduction reaction due to their intriguing properties, such as high electrical conductivity, structural flexibility, and low cost. Platinum and its alloys supported on carbon are currently considered the benchmark catalysts for the oxygen reduction reaction (ORR) in Proton Exchange Membrane Fuel Cells (PEMFCs). Confining platinum within the pore system of mesoporous carbon prepared by hard-templating has proven to be an effective way to mitigate catalyst degradation in PEMFCs.[1] However, the challenge of template removal and the limited yield have hindered its practical application in industry. As a remedy, we establish a simple synthesis of carbon gels through sol-gel polymerization of resorcinol (R) and formaldehyde (F), ultimately resulting in graphitic mesoporous carbons.The synthesis process involves mixing resorcinol and formaldehyde in the presence of a basic catalyst, followed by heating for a certain period of time to obtain crosslinked gels.[2] Specific metal salts can be incorporated into the reaction to synthesize mesoporous and highly graphitic carbon spheres (GRF-Sphere) in a straightforward manner, without the need for hydrothermal steps, solvent exchanges, supercritical drying, or post-activation techniques. While conventional carbonized RF spheres are typically non-graphitic and microporous (Fig. 1.), modification of the synthesis route allows for the production of mesoporous, highly graphitic carbon spheres (GRF-Sphere) by taking advantage of the porogenic and graphitization effect of Fe(acac)2. Platinum nanoparticles with an average size of ca. 3 nm were deposited into the pores of GRF-spheres by incipient wetness impregnation followed by annealing at 750 °C. The specific activity of the Pt/GRF-Sphere catalyst for the ORR was found to be greater than 0.45 mA cm-2 Pt at 0.9 V vs. RHE, which in comparison with the literature indicates high catalytic activity.[3] The confinement of the active phase within the pores of the GRF-Spheres contributed to enhancing the stability of the catalyst, as confirmed by an accelerated stress test performed within the typical operating range of a PEMFC (0.6 - 1.0 VRHE). The Pt/GRF-Sphere was found to retain a significantly higher proportion of active surface area when compared to a reference Pt/Vulcan catalyst with similar platinum particle size (Fig. 1.).Furthermore, increasing the concentrations of resorcinol and formaldehyde by 25-fold resulted in the synthesis of a mesoporous and highly graphitic gel, namely GRF-Gel, at a substantial volume yield of70 g L-1, which underlines the potential for this process to be scaled up for industrial application. The ORR activity and stability of GRF-Gel in RDE are currently being investigated. Moreover, the electrochemical performance of this material will be evaluated in a single-cell PEMFC in collaboration with the group of Prof. Hubert Gasteiger (TU Munich).Overall, this research provides a promising and straightforward approach to synthesize highly graphitic mesoporous carbon materials using iron acetylacetonate as a porogen and graphitization catalyst. The method is based on the established preparation of RF-gels but includes iron salts. We have demonstrated that Pt/GRF-Sphere, which is produced by depositing Pt nanoparticles into the pore system of the GRF-Sphere, exhibits high activity and stability for the ORR. Given the simplicity and scalability of our synthesis procedure and the tailored morphology of these carbon materials, we believe that Pt/GRF-Sphere and Pt/GRF-Gel have great potential for industrial applications. Acknowledgement: We acknowledge the financial support from the German Federal Ministry for Economic Affairs and Energy (BMWi) in the framework of POREForm (project number 03ETB027F).

(Invited) Insights into Processes at the Electrode/Electrolyte Interface of Battery Electrodes Via Scanning (Electrochemical) Probe Microscopy

Scanning (electrochemical) probe microscopy (SEPM) techniques such as atomic force microscopy (AFM), scanning electrochemical microscopy (SECM), nano-pipette derived scanning probe methods like scanning electrochemical cell microscopy (SECCM) and hybrid methods have recently been used to study interfacial processes occurring at solid/electrolyte interfaces of battery electrodes [1]. So far, mainly Lithium-ion battery (LIB) electrodes have been studied, such as the solid-electrolyte interphase formation at graphite anodes [2,3]. Next generation battery chemistries, using earth abundant elements like sodium (Na), potassium (K), aluminum (Al) improving sustainability still suffer from insufficient knowledge of processes occurring during cycling at the electrode/electrolyte interface such as interphase formation, as gained insights from Li batteries cannot simply be transferred to post-Li chemistries.In this contribution, an overview of the potential of SEPM techniques to gain insight in interfacial process of post-Li battery chemistries will be given, focusing mainly on the SEI formation on hard carbon composite anodes for Na-ion batteries (SIBs) [4]. The influence of the electrolyte composition along with the effects of additives on the SEI formation and the nanomechanical properties of the electrode will be presented. In addition, given the abundance of Al and the high theoretical volumetric capacity, makes Al a highly attractive battery chemistry [5]. Despite these advantages, there are several challenges like the Al2O3 passivating layer and the mostly used acidic ionic liquid (IL)-based electrolyte AlCl3/1-ethyl-3-methylimidazolium chloride [EMIm]Cl that leads to corrosion, which determines the plating and stripping efficiency and therefore the overall performance. First correlative SECCM/EDX/EBSD studies on Al anodes will be presented. Acknowledgement This work contributes to the research performed at CELEST (Center for Electrochemical Energy Storage Ulm - Karlsruhe) and was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany's Excellence Strategy – EXC 2154 – Project number 390874152 (POLiS Cluster of Excellence).

Analysis of Technical and Economics High Voltage Overhead Transmission 150 kV Development in Industrial Area of High Voltage Consumers PT. Lotte Chemical Indonesia

In order to increase revenue, PT PLN (Persero) entered into a power purchase agreement with PT. Lotte Chemical Indonesia Cilegon. investment in the relocation of 150 kV high voltage overhead lines. This research is very important as a small-scale simulation given the large number of electric power transmission projects implemented by PLN. This study analyzes the impact of the relocation of the 150 kV T/L and found that the existing material that was dismantled was either utilized/not reused so that it has the potential to increase/decrease investment for PLN. The research method is in the form of data analysis on the feasibility study of the PLN project. Calculation analysis by calculating the value of existing assets which is then used as a reference in calculating sensitivity analysis which is then determined 3 scenarios using financial indicators IRR, NPV, B/C Ratio and Payback Period (PB). The results of the study show that scenarios 1, 2 and 3 have positive IRR and B/C ratio values and there is a difference of 1 year for the payback period between scenarios 1 and 3 vs scenario 2 and the highest NPV is in scenario 3.

Chronic intermittent hypoxia attenuates noradrenergic innervation of hypoglossal motor nucleus

The state-dependent noradrenergic activation of hypoglossal motoneurons plays an important role in the maintenance of upper airway patency and pathophysiology of obstructive sleep apnea (OSA). Chronic intermittent hypoxia (CIH), a major pathogenic factor of OSA, contributes to the risk for developing neurodegenerative disorders in OSA patients. Using anterograde tracer, channelrhodopsin-2, we mapped axonal projections from noradrenergic A7 and SubCoeruleus neurons to hypoglossal nucleus in DBH-cre mice and assessed the effect of CIH on these projections. We found that CIH significantly reduced the number of axonal projections from SubCoeruleus neurons to both dorsal (by 68%) and to ventral (by73%) subregions of the hypoglossal motor nucleus compared to sham-treated animals. The animals’ body weight was also negatively affected by CIH. Both effects, the decrease in axonal projections and body weight, were more pronounced in male than female mice, which was likely caused by less sensitivity of female mice to CIH as compared to males. The A7 neurons appeared to have limited projections to the hypoglossal nucleus. Our findings suggest that CIH-induced reduction of noradrenergic innervation of hypoglossal motoneurons may exacerbate progression of OSA, especially in men.

Identifying Causes of Claims in The Egyptian Construction Sector

This research aims to study the causes of claims in the construction industry. The scope of the study is located in Egypt because of the huge number of projects in the construction sector. The occurrence of claims between the parties involved in the project (the owner, consultant, and contractor) leads to a loss of time, money, and effort. Knowing the causes of claims leads to avoiding them and thus increasing the chances of success of construction projects. The factors and causes of claims in the construction industry were determined by reviewing previous studies and interviewing experts working in the field, then A questionnaire survey was conducted and 385 specialists in the construction industry were exposed Statistical analysis was done, and the results concluded that the most important causes of claims in the construction industry in Egypt are: increase in cost due to changes prices, lack of funding to the contractor, change and fluctuation of the exchange rate and the rate of inflation changes in design and specifications, Increases in costs and quantities more than 25% of the contract value, increases of variation orders, lack of coordination between the design and implementation processes and delay to get approvals and permissions. Mitigation actions proposed to deal with avoid claim factors revolve around a good study of the contract documents at the tender stage, good coordination, and careful follow-up by the participating parties during the ring construction phase.

The Architectural Activity in Lithuania During the First Soviet Occupation (1940–1941)

During the first Soviet occupation of Lithuania, which lasted from June 1940 to June 1941, gradual changes were planned to be implemented in the country’s field of architecture. Although the occupation was short and lasted only a year, the design structure was changed according to the Soviet model, many architectural ideas were planned to be implemented, and a number of design projects of the new buildings were developed. Therefore, this article, based mainly on archival and historical material, analyses the architectural activity and the peculiarities of this process that took place in Lithuania during the first Soviet occupation.

Multi-effect equilibrium analysis for sector-level direct/indirect socio-economic and environmental effects of large-scale hydropower initiatives: A case study for the world's 7th-largest hydropower project

An increasing number of large-scale hydropower projects (LHPs) are constructed in various countries to combat climate change. Besides hydropower generation, LHPs could also contribute to water supply, irrigation, navigation, flood control, and other comprehensive benefits. Thus, it is essential to quantitatively analyze the overall and sub-functional benefits of LHPs in their operational phase. In this study, a multi-effect LHP equilibrium analysis model has been proposed and applied to the Wudongde Hydropower Station (WDD) to investigate its sector-level direct/indirect socio-economic and environmental (SEE) effects. The results indicate that WDD's operation greatly promotes the regional socio-economic growth and facilitates the greenhouse gas (GHG) emission reduction. The increased value of indirect gross domestic product (GDP) is equivalent to 0.027% of the total GDP of the Yangtze River Economic Belt in 2021, and the annual decreased amount of indirect GHG emissions is about 260.8 million tonnes. The results shed light on the contributions of different sub-functions of LHP to SEE indicators, which plays a pivotal role for decision-makers in formulating LHP-related operational planning and GHG emission reduction policies. Moreover, the modeling framework can be extended to assess the SEE effects of other LHPs around the world.

Assessing conceptual comparability of single-item survey instruments with a mixed-methods approach

An increasing number of research projects and infrastructure services involve pooling data across different survey programs. Creating a homogenous integrated dataset from heterogeneous source data is the domain of ex-post harmonization. The harmonization process involves various considerations. However, chief among them is whether two survey measurement instruments have captured the same concept. This issue of conceptual comparability is a fundamental precondition for pooling different source variables to form a harmonized target variable. Our paper explores this issue with a mixed-methods approach. On the one hand, we use psychometric latent variable modeling by presenting several single-item wordings for social trust to respondents and then performing factor analytic procedures. On the other hand, we complement and contrast these quantitative findings with qualitative findings gained with an open-ended web probe. The combined approach gave valuable insights into the conceptual comparability of the eleven social-trust-related single-item wordings. For example, we find that negative, distrust-related wordings and positive, trust-related wordings should not be pooled into an integrated variable. However, the paper will also illustrate and discuss why it is easier to disprove conceptual comparability than fully prove it.

The AI Work of Art in the Age of its Co-Creation

Almost one century after Walter Benjamin’s dissertation on the value of the work of art under the impact of its technological reproduction on the roots of globalization and mass media society, the current research aims to provide some coordinates to approach the influence of AI co-creative processes in the artistic field. From a media archaeological approach, we will map the collaborative practices that emerge in the Generative Art landscape to understand the creative possibilities of interaction between humans and machine-driven artistic goals. By conceiving the Web 3.0 as an expansive megadungeon, we find an increasing number of projects based on participative dynamics where online communities join forces with AI decentralized artists to reshape the current state of the art. We will take as an example the Botto Project, a community-driven creator conceived by Mario Klingemann, a pioneer of AI artworks who employs machine learning methods to revolutionize the blockchain and crypto art market. This case study leads us to reconsider the (wo)man-machine co-creation as the base of the auratic experience of the work of art in the age of AI co-creativity.

Dynamic prediction of malignant ventricular arrhythmias using neural networks in patients with an implantable cardioverter-defibrillator

Risk stratification for ventricular arrhythmias currently relies on static measurements that fail to adequately capture dynamic interactions between arrhythmic substrate and triggers over time. We trained and internally validated a dynamic machine learning (ML) model and neural network that extracted features from longitudinally collected electrocardiograms (ECG), and used these to predict the risk of malignant ventricular arrhythmias. A multicentre study in patients implanted with an implantable cardioverter-defibrillator (ICD) between 2007 and 2021 in two academic hospitals was performed. Variational autoencoders (VAEs), which combine neural networks with variational inference principles, and can learn patterns and structure in data without explicit labelling, were trained to encode the mean ECG waveforms from the limb leads into 16 variables. Supervised dynamic ML models using these latent ECG representations and clinical baseline information were trained to predict malignant ventricular arrhythmias treated by the ICD. Model performance was evaluated on a hold-out set, using time-dependent receiver operating characteristic (ROC) and calibration curves. 2942 patients (61.7±13.9 years, 25.5% female) were included, with a total of 32,129 ECG recordings during a mean follow-up of 43.9±35.9 months. The mean time-varying area under the ROC curve for the dynamic model was 0.738±0.07, compared to 0.639±0.03 for a static (i.e. baseline-only model). Feature analyses indicated dynamic changes in latent ECG representations, particularly those affecting the T-wave morphology, were of highest importance for model predictions. Dynamic ML models and neural networks effectively leverage routinely collected longitudinal ECG recordings for personalised and updated predictions of malignant ventricular arrhythmias, outperforming static models. This publication is part of the project DEEP RISK ICD (with project number 452019308) of the research programme Rubicon which is (partly) financed by the Dutch Research Council (NWO). This research is partly funded by the Amsterdam Cardiovascular Sciences (personal grant F.V.Y.T).

Экологические проекты инициативного бюджетирования

Ecological projects of initiative budgeting are considered in the article as a form of involving citizens in the ecological agenda. The classification of ecological projects initiated by citizens was compiled by the authors. These are projects of organizing the collection of solid waste and garbage, projects in the field of fire safety, projects to provide settlements with clean drinking water. Based on the database of the All-Russian contest of the best projects of initiative budgeting, numerical indicators on the implementation of ecological projects (number, cost, beneficiaries) were selected. The foreign experience of involving citizens in the environmental agenda – green participatory budgeting – was presented. The unique experience of involving schoolchildren and youth in climate and environmental issues in some foreign countries was described. A review of Russian initiative projects in the field of ecology was carried out. It is concluded that there is the emergence of a trend to involve citizens in the ecological agenda. Initiative budgeting projects serve as indicators of the actual requests and needs of citizens. It is also noted that it is reasonable to use the database of the All-Russian competition of initiative budgeting projects as a unique information resource about the practices of civic engagement.