The 15th Global Conference on Materials Science and Engineering (CMSE 2026)

Abstract: Monitoring both temporal and spatial distributions of transitory electro-magnetic fields represents a challenge with frontier applications. High-power laser-matter interaction is just one of the examples in which such transient electro-magnetic fields are produced, and where such a field monitoring would be of a real interest in characterizing the interaction itself, an interaction otherwise relatively hard to monitor and control. Starting from some previously developed theoretical and experimental correlations between High-Power Laser-Matter interaction parameters and associated pulsed electromagnetic fields (EMP) parameters, here we present some results on magnetic field spatial and temporal measurements, for 2D areas of about 1 cm² and temporal duration of ms order. System calibration results were performed based on material theoretical parameter values as well as experimentally measured parameter values. Field measurement experimental values are compared with field theoretical calculations as well as other experimental results obtained with different ‘standard’ calibrated tools (e.g. Hall probe). Furthermore, based on Electro-Optical materials, similar results could be obtained for electric field spatial and temporal variations. Comparative results for such systems are presented and discussed, as well as perspectives of such measurement and monitoring techniques in relation with high-power laser-matter interactions characterization and diagnosis.

Keywords: Non-linear optic materials, transitory electro-magnetic field monitoring, laser-matter interactions.

Acknowledgments: We acknowledge funds from the Ministry of Research, Innovation and Digitization / Institute of Atomic Physics, through ELI-RO 30/2024, Eli-RO 30/2025 support of the National Interest Infrastructure facility IOSIN – CETAL at INFLPR and Program contract No. 39/2024, Romanian National Core Program LAPLAS VII contract No. 30N/2023.

Abstract: As a Laboratory dedicated to technological transfer in the field of laser welding and additive manufacturing, a significant interest is devoted to the quality control of produced parts. During the development of technologies, we usually monitor in situ the experiments via high-speed imaging and thermography. One of our purposes is to identify as fast as possible the defects, so that to be able to separate the conform parts from the deviant ones non-destructively. If there are no possible associations between features of the plasma plume during laser processing and the defects that appear during processing, X-ray imaging (radiography/tomography) is the selection of choice for non-destructive defects assessment.

The presentation will focus on examples of technologies that are developed for various companies in Romania, that take into consideration the non-destructive defects assessment and possible correlations between processing features and defects outcome in case of processing of metal matrix composites and metal alloys.

Correlations between metallographic analyses and area/intensity of the hot vapor in various locations of the samples help to automize the in-situ quality control of samples. Based on the characterization of the hot vapor, it has been found that the increase of the vapor area that exceeded a threshold value was a sign of pores formation within the weld seam.

In parallel, X-ray tomography allows for fast defects identification, thus reducing the necessity for metallographic preparation of samples and manual optical microscopical observations, thus reducing significantly the time for quality control in case of companies adopting our technologies.

Keywords: laser welding, high-speed imaging, porosity control, hot vapor, process optimization, X-ray imaging characterization

Abstract: Lithium–sulfur (Li–S) batteries are promising next-generation energy storage systems due to their high theoretical energy density, yet their practical application is hindered by sluggish sulfur redox kinetics, severe polysulfide shuttling, and interfacial instability. This talk presents a unified framework that advances from material design to fundamental reaction physics. We first show that intrinsic catalytic activity is governed by bulk electronic structure. Transition-metal doping in ZnSe tunes orbital hybridization and enables control of sulfur redox kinetics. This concept is extended through defect–dopant coupling in MoS₂, where inner-layer doping stabilizes vacancies and creates electronically active sites with enhanced charge transfer. We then demonstrate that catalytic performance is also limited by reaction pathway constraints. Dual-doped MnO₂ enables bidirectional catalysis, accelerating both Li₂S formation and decomposition. However, single-site systems face intrinsic trade-offs between adsorption and conversion. To overcome this, a dual-terminal binding strategy spatially decouples polysulfide trapping and catalytic conversion, enabling simultaneous shuttle suppression and fast kinetics. At the atomic level, diatomic catalysts introduce cooperative interactions between active sites, enabling coupled electronic and spin effects beyond single-site limitations. Finally, we identify the fundamental origin of the rate-limiting step. The Li₂S₂ → Li₂S conversion is governed by spin-state transitions rather than purely thermodynamic barriers. Machine learning further reveals that spin density strongly correlates with reaction energetics. This work establishes spin-dependent reaction pathways as a universal design principle for high-performance Li–S batteries.
Keywords: Lithium-sulfur batteries, Spin-state engineering, Electronic structure modulation, Electrocatalysis, Reaction kinetics

Acknowledgements: This work was supported by the Science and Technology Development Fund, Macau SAR (File no. 0022/2023/RIB1), University of Macau (File no. MYRG-GRG2024-00166-IAPME and MYRG-GRG2025-00136-IAPME), the Science and Technology Innovation Committee of Shenzhen Municipality (SGCX20250526152800001), Guangdong Basic and Applied Basic Research Foundation 2026A1515012355 and the High-Performance Computing Cluster (HPCC) of Information and Communication Technology Office (ICTO) at University of Macau.

Abstract: Nanoporous carbon textiles (NCTs) are very promising materials in many applications including wearable electronic devices, sensors or adsorbents, as they have a wide range of advantages including high conductivity, flexibility, and low cost [1]. Due to developed porous structure and surface chemistry they do not need to undergo aggressive exfoliation (such as a modified Hummers method used for graphene) or aggressive chemical activation (used for nonporous carbon fibers). NCTs can also be used to fabricate advanced nanocomposites, e.g. based on MOFs or recently reported by us carbon-sulfur nanocomposites [2]; cf. Fig. 1).

Figure 1. Schematic presentation of the sulfur insertion scheme

Abstract: Liquid crystal polymer networks are one of the most promising advanced materials for the development of responsive devices. These materials have been used as actuators, soft robots, sensors, photonic devides, etc. A crucial requirement for achieving the full potential of liquid crystal networks is the continued development of new methods to synthesize and assemble them. During the previous decades these processes have been revolutionized several times, and this process is still ongoing today. Here, several advanced methods for the assembly of responsive liquid crystal polymer networks will be presented. One kind of material that will be discussed contains covalent bonds that can be established and broken under controlled circumstances to achieve reprocessibilty and recycling. A key requirement for these materials is that the stimuli-responsive behavior is kept intact after the assembly is completed. The second kind of material is a (semi)-interpenetrating network between a cholesteric polymer network and a responsive polymer. The cholesteric network reflects light of a wavelength determined by the pitch of the cholesteric helix, and the secondary polymer bestows the material with stimuli-responsiveness. The resulting material has potential for the development of photonic sensors that provide an optical signal when a specific stimulus is present to alert a user of the presence of this stimulus.

Abstract: Various types of porous biodegradable polymers based on polycaprolactone (PCL), polylactide (PLA), and polyurethane were synthesized and used as drug delivery vehicles for bupivacaine and carboplatin. Porous biodegradable microspheres were fabricated by successful RAFT polymerization of methyl vinyl ketone (MVK) onto PCL and PLA, which was first synthesized by ring opening polymerization of lactide followed by an oil/water emulsion-evaporation method, then finally photodegradation of PMVK blocks by UV irradiation. Biodegradable porous polyurethane nanoparticles have also been fabricated using water-in-oil-in-water double emulsion and solvent evaporation methods. These nanoparticles are composed of biodegradable and biocompatible polyfumarateurethane (PFU) and L-threonine polyurethane (LTHU), designed for degradation through hydrolysis and enzymatic activity, facilitated by the presence of ester bonds and peptide bonds within the polymer backbone. Gel permeation chromatography (GPC) was used to evaluate the molecular weight and molecular weight distribution and monitored the photodegradability of the block copolymers. For photodegradation by UV light under dried condition, the molecular weight of triblock copolymer was decreased gradually with UV irradiation time, reaching close to that of macro-CTA, meaning that 90% of PMVK block was photodegraded after 24 h of UV irradiation. The morphology of microspheres was spherical with smooth surfaces before UV irradiation. Microspheres fabricated only from PCL homopolymers could also retain their smooth surface after UV irradiation. However, those from PCL-PMVK and PCL-PLA-PMVK block copolymers had rough surfaces and porous structures after UV irradiation due to the photodegradation of PMVK blocks as a porous template. The porosity and shape of the microspheres and shape of microspheres were dependent on the PMVK contents and size of microspheres. In addition, the drug loading, encapsulation efficiency, and drug release profiles, using UV-Vis spectroscopy, showed the highest encapsulation efficiency with 2.5% drug, and sustained release profile.

Keywords: Biodegradable, thermoresponsive, hollow porous, micro/nanoparticles, sustained drug release.

Abstract: With the rapid development of high-performance computing and artificial intelligence, electronic devices face growing heat dissipation challenges, driving the need for novel thermal interface materials (TIM). Hexagonal boron nitride (h-BN) offers excellent in-plane thermal conductivity and insulation, making it an ideal filler for TIM. However, traditional methods achieve only single-orientation alignment of boron nitride nanosheets (BNNS), limiting synergistic improvement of both in-plane and through-plane thermal conductivity.

This study proposes a magnetic field-assisted tape casting method to construct a three-dimensional (3D) BN network within an epoxy resin (EP). Glycine-modified h-BN (Gly-BN) and BNNS were first obtained via ball-milling assisted liquid-phase exfoliation. Then, Fe₃O₄ was synthesized onto BNNS to produce magnetically responsive Fe₃O₄@BNNS. During tape casting under a vertical magnetic field, mechanical shear force induced horizontal alignment of Gly-BN, while the magnetic field aligned Fe₃O₄@BNNS vertically, forming a dual-orientation 3D network. When the mass ratio of Fe₃O₄ to BNNS in F@B is 1:1 and the applied magnetic field strength is 60 mT, the dual-orientation composite with 30 wt.% filler content gave optimal overall performance: in-plane conductivity of 4.86 W/(m·K) and through-plane conductivity of 1.84 W/(m·K).

This work demonstrates that magnetic field-assisted tape casting, combined with exfoliation and magnetic modification of BN, enables a dual-orientation 3D thermal conductive network, significantly enhancing both in-plane and through-plane thermal conductivity for advanced thermal management.

Keywords: Thermal interface materials, hexagonal boron nitride, thermal conduction performance, orientation.

Acknowledgements: This work was supported by the National Natural Science Foundation of China (No. 52202070).

Abstract: Spin-crossover (SCO) materials exhibit reversible high-spin (HS, S = 2) ↔ low-spin (LS, S = 0) transitions in response to external stimuli, making them promising candidates for adaptive sensing, energy conversion, and molecular-scale information processing. In this work, a new Fe(II)-based SCO complex was synthesized and systematically investigated using high-pressure structural, vibrational, optical, thermal, and magnetic characterization techniques, including X-ray diffraction, Raman and infrared spectroscopy, UV–Vis absorption spectroscopy, differential scanning calorimetry, and SQUID magnetometry. Structural studies reveal a pressure-induced spin transition from the HS state (< 0.7 GPa) through a mixed-spin region (~0.8–2.0 GPa) to a complete LS state (> 2.5 GPa). In contrast, the magnetic measurements demonstrate that increasing pressure shifts the spin-transition temperature toward higher temperatures, broadens the thermal hysteresis from 60 to 130 K, and stabilizes the complete HS state in the LS region at pressures above 0.1 GPa. These results provide new insights into the structure–property relationships governing Fe(II)-based SCO systems and highlight their potential for the development of next-generation molecular memory materials.

Keywords: Spin-crossover phenomenon, spin transition, magnetic susceptibility, Fe(II), high pressure

Abstract: The transition of flexible electronics from laboratory prototypes to foundry-enabled integrated-circuit platforms changes the design questions for circuit designers. Demonstrating that thin-film transistors can implement a function is only one part of the task. Designers must also determine how to build useful systems when device polarity, gain, speed, variability, environmental sensitivity, and model maturity differ fundamentally from those of silicon. This contribution presents a microelectronic designer’s perspective on commercially accessible IGZO n-type TFT technologies, supported by recent circuit and system demonstrations.
Three examples illustrate the design space. An ultra-low-power wake-up timer uses transistor leakage as part of its operation. It generates a mean signal frequency of 0.24 Hz while consuming 26.7 nW. An n-FET-only operational amplifier demonstrates low-frequency analog signal processing with a power consumption below 33 µW. A flexible low-dropout regulator operates with approximately 1 µA quiescent current. It was used to power the 1.3 V rail of a solar-powered sensing node for 5.57 h.
Together, these results show that flexible technologies can support timing, analog signal conditioning, and power management. They also reveal constraints that cannot be predicted from nominal device performance alone. These include chip-to-chip dispersion, limited voltage headroom, and sensitivity to temperature and light. Long-term drift and differences between compact-model predictions and measurements must also be considered.
The presentation will discuss the resulting design methodology. Functions should be selected according to the capabilities of the technology, and the device physics should be used where it provides a circuit-level advantage. Designs also require validation across multiple samples and under realistic operating conditions. In addition, performance should be evaluated at the level of the complete hybrid system. The presentation will also consider sustainability. Commercial availability makes environmental claims easier to test, but it does not demonstrate an environmental benefit by itself. Such benefits require function-based evidence supported by life-cycle analysis.

Keywords: Flexible integrated circuits, IGZO transistors, circuit design, low-power electronics, power management
Acknowledgements: JDP acknowledges the sponsorship of the Alexander von Humboldt Professorship of the Humboldt Foundation and the Federal Ministry for Education and Research (Germany).

Abstract: Nb-Si-based ultrahigh temperature alloys, with their high melting point, low density, and excellent mechanical properties at both room and elevated temperatures, are promising candidates for next-generation high-temperature structural materials in aircraft engines. Alloying is a key approach to improving the overall performance of Nb-Si based ultrahigh temperature alloys, particularly their high temperature oxidation resistance. The effects of elements such as Ti, Cr, Al, Hf, B, V, Zr, and Mo, as well as their combined influences on microstructure and properties, have been clarified, leading to the development of novel multi-component Nb-Si based ultrahigh temperature alloys with superior comprehensive performance.

The integral directional solidification technique (IDS) significantly increases the axial temperature gradient, avoiding strong convection and skin effect in the melt ahead of the solid/liquid interface during zone melting directional solidification. This enables the fabrication of alloys with excellent directional growth and outstanding mechanical properties. As the withdrawing rate increases, the number of eutectic cells in the directional solidified microstructure increases, while the average diameter of eutectic cells and the interlamellar spacing within them decrease, enhancing the characteristics of eutectic coupled growth. The integral directional solidification markedly improves the alloy's room-temperature fracture toughness, high-temperature tensile strength, and creep resistance. After whole-body directional solidification, the average K_Q value reaches 26.8 MPa·m^1/2, the tensile creep life at 1200 °C/75 MPa reaches 216 hours, the tensile strength at 1400 °C reaches 191.7 MPa, and that at 1500 °C reaches 113.8 MPa. A shell mold suitable for investment casting of Nb-Si based ultrahigh temperature alloy turbine blades has been developed, and a directionally solidified turbine blade made from Nb-Si based ultrahigh temperature alloy was successfully produced under a molten metal temperature of 2000 °C.

Keywords: Nb-Si based alloy, Alloying effects, Directional solidification, Tensile stress rupture properties, Turbine blade

Abstract: Bubble collapse near solid boundaries can generate highly localized impact loads that lead to material damage. In many practical systems, the structure is not a semi-infinite solid but a thin plate, and its response is influenced by the boundary condition behind the wall. In this study, the collapse of a single gas bubble near a thin solid plate is investigated using numerical simulations. The model consists of a compressible fluid (water or mercury), a gas bubble, and an elastoplastic solid plate, coupled through fluid–structure interaction. Bubble collapse is induced by an incident shock wave, and the resulting pressure, stress, and plastic strain in the plate are evaluated. The results show that bubble collapse generates localized pressure peaks on the wall surface, leading to significant plastic deformation. The magnitude and spatial distribution of the deformation depend on the backing condition of the plate. Compared with a transmissive boundary, a void region behind the plate increases deformation and modifies the damage pattern. In addition, differences between water and mercury are observed. Mercury produces higher and longer pressure pulses, resulting in more localized loading. These results indicate that the impact load and resulting damage cannot be evaluated assuming a semi-infinite solid, and that both structural configuration and fluid properties must be considered.

Abstract: Metallic glasses (MGs) could be obtained by quenching from the melt at a rate high enough to suppress nucleation/growth of crystalline phases, and they have a glass-like amorphous structure. Because of the amorphous structure, MGs have no grain boundaries/dislocations and hence possess very high strength (~2 GPa). Also, like glasses, MGs have polymer-like viscous flow behavior at temperatures above the glass transition temperature, T_g. MGs provide a challenge of engineering applications for their unique structure and properties. However, plasmonic applications have been rarely explored for MGs. In this work, we unveiled that certain compositions of Au-based MGs possessed negative dielectric constants and could be used as plasmonic materials. Furthermore, with a low glass transition temperature of Au-based thin film MGs (TFMGs), we were able to fabricate large dimensions of nanostructures using an inexpensive thermal imprint method in air instead of other costly lithography methods.

We fabricated fully amorphous AuCuSi TFMGs using magnetron sputtering, and performed nanoindentation creep tests in the temperature range of 50 ºC to 170 ºC to characterize the viscous flow behavior and to determine the T_g of the film. We fabricated nanostructures by thermal imprinting on the film at a temperature slightly above the T_g, and conducted both measurements and simulations to demonstrate that our fabricated nanostructures were suitable for surface-enhanced Raman scattering (SERS) applications. It is worth noting that in the absence of grain boundaries in amorphous TFMGs, damping due to increased scattering at grain boundaries does not occur and SERS could be improved. Also, compared to regular SERS substrates of textured Si with deposited Au films, imprinted Au-based TFMGs provided complete coverage of Si underneath and the vibrational signal of Si lattice would not show in Raman spectra to possibly overlap signals of analyte and decrease the accuracy of sensing. Our results suggested new avenues for applying a low-cost and high-throughput method on AuCuSi TFMGs to fabricate large dimensions of substrates for plasmonic applications.

Keywords: Thin film metallic glasses, sputtering, Nanoindentation, thermal imprint, surface-enhanced Raman scattering.

Acknowledgements: This work was supported by the National Science and Technology Council, Taiwan under Contract no. NSTC 115-2221-E-002-032

Abstract: With advanced research for dielectrics including capacitors in DRAMs, decoupling filters in microcircuits and insulating gates in transistors, a lot of demand for the new challenging of high-k materials in semiconductor industries has been emerged. This study explores and addresses the experimental approach for composite materials with one of the major concerns of high capacitance, and low leakage, as well as ease of integration technology. The characteristics of Al₂O₃ supported HfO₂ (AHO) thin films for a series of different Hf ratios with Al₂O₃ dielectrics by atomic layer deposition demonstrated as a candidate material. A composite AHO films with the homogeneous compositions of Al and Hf atoms into the Al-Hf-O mixed oxide system could stabilize the polycrystalline structure with increasing of dielectric constant (k) and decreasing of leakage current density, as well as a higher breakdown voltage than HfO₂ film on its own.

In this report, 70 nm thick AHO thin films with different composition of Al and Hf contents were prepared by atomic layer deposition technique on titanium nitride (TiN) and silicon dioxide (SiO₂) coated Si substrates. Photolithography and metal lift-off technique were used for the device fabrication of the metal-insulator-metal (MIM) capacitor structures. AHO films on TiN/SiO₂/Si were measured by semiconductor analyser and source/measure system with probe station in the voltage range from -5 to 5 V with a frequency range from 10 kHz to 1 MHz were used to conduct capacitance-voltage (C-V) measurements with low/medium frequency range and current-voltage (I-V) measurements. It was found that Au/AHO/ TiN/SiO₂/Si MIM capacitors demonstrate a capacitance density of 1.5 - 4.5 fF/μm² at 10 kHz, a loss tangent of 0.02 - 0.04 at 10 kHz, dielectric constant of 11.7 - 35.5 depending on the composition and a low leakage current of 1.7×10^-9 A/cm² at 0.5 MV/cm at room temperature. The acquired experimental results could show the possibility of compositional alloy thin films that could potentially replace or open new market for high-k challenges in semiconductor technology.

Keywords: Thin film, atomic layer deposition, high-k composites, laminated dielectrics.

Reference:
[1] Payne A. et al. Appl. Phys. Lett., 117(22), 221104 (2020)
[2] Wang Y. et al., Adv. in Mat. Phys. and Chem., 11, 7-19 (2021)

Abstract: Hydrogen is clearly one of the protagonists of the energy transition. Currently, there are more than a thousand projects announced globally for the development of hydrogen technologies with a focus on carbon neutrality by 2050. Hydrogen consumption has been close to its production, which means that its storage and long-distance transport do not yet play a decisive role in its value chain. However, with the introduction of the concept of green hydrogen, using renewable energy as an energy source for electrolysis, hydrogen production may not coincide with peak consumption times. This makes storage crucial to meet demand. For hydrogen storage, it is essential to ensure the isolation of reservoirs in order to preserve the hydrogen's conditions. Cork, due to its cellular structure, combines a set of thermal insulation and crashworthiness properties allied to low density, that make it a suitable material for this type of application. In this presentation, different opportunities were analyzed where the mechanical impact requirements and fire resistance were studied as well as permeability. It is shown that cork composites, alone or combined with other materials, can contribute to a more sustainable solution, performing similarly to the solutions traditionally used.

Keywords: Cork, Hydrogen, Composites.

Acknowledgements: The present study was developed in the scope of the Project “Agenda ILLIANCE” [C644919832-00000035 | Project No. 46], financed by PRR – Plano de Recuperação e Resiliência under the Next Generation EU from the European Union.

Abstract: Understanding photoinduced chemical reactions at the electronic, atomic, and molecular length scales and on relevant timescales is essential for controlling reaction pathways, rates, and efficiencies. This knowledge is crucial for applications including catalysis, photoswitching, and light harvesting. X-ray free-electron lasers (XFELs) generate intense, ultrashort X-ray pulses, enabling chemical processes to be probed with high spatial and temporal resolution. Here, we use femtosecond XFEL pulses to investigate the ultrafast dynamics of the model photocatalyst [Ir₂(dimen)₄]²⁺ in solution (dimen = 1,8-diisocyano-p-menthane) [1]. Time-resolved X-ray solution-scattering experiments are combined with angular cross-correlation analysis to facilitate molecular structure determination in solution [1-4].

We perform a model-assisted analysis of the experimental X-ray scattering correlations, allowing us to elucidate several aspects of photoinduced structural changes in molecular ensembles [1]. We unambiguously determine that the photoinduced transition dipole moments in [Ir₂(dimen)₄]²⁺ are oriented perpendicular to the Ir–Ir bond. Our analysis further shows that the ground-state conformer with the larger Ir–Ir distance is predominantly responsible for excited-state formation. In addition, we demonstrate that the solute ensemble exhibits substantial structural heterogeneity arising from solvent effects.

The proposed correlation-based approach provides a complementary method for studying ultrafast structural dynamics in molecular ensembles in the liquid and gas phases, with relevance to catalysis, photosynthesis, nanoscience, and bioimaging [3,4].

Keywords: Ultrafast dynamics, x-ray free-electron laser, photoexcited molecules, x-ray cross-correlation analysis.

References:
[1] R. P. Kurta et al., Phys. Chem. Chem. Phys. 25, 23417 (2023)
[2] P. Vester et al., Struct. Dynamics 6, 024301 (2019)
[3] R. P. Kurta, M. Altarelli, I. A. Vartanyants, Adv. Chem. Phys. 161, Ch.1 (2016)
[4] R. P. Kurta, L. Wiegart, A. Fluerasu, A. Madsen, IUCrJ 16, 635 (2019)

Abstract: The growing demand for clean water and the increasing complexity of water contaminants have driven the search for advanced materials capable of enhancing the efficiency and sustainability of water treatment processes. MXenes, a rapidly expanding family of two-dimensional (2D) transition metal carbides, nitrides, and carbonitrides, have attracted significant attention due to their high surface area, tunable surface chemistry, excellent hydrophilicity, and remarkable adsorption and separation capabilities. These unique characteristics position MXenes as promising candidates for a wide range of water treatment and desalination applications. This presentation highlights recent progress in the development and application of MXenes and MXene-based composites for the removal of emerging contaminants, desalination, membrane separation, adsorption, and advanced water purification systems. Particular emphasis will be placed on the structure-property relationships that govern their performance and the strategies employed to improve selectivity, stability, and operational efficiency. Despite their considerable potential, challenges related to large-scale synthesis, long-term stability, membrane fouling, environmental safety, and commercial deployment remain significant barriers to practical implementation. Current research gaps, technological limitations, and future opportunities will be discussed, providing insights into the pathways required to translate MXene-based technologies from laboratory research to real-world water treatment applications.

Keywords: MXenes, Water Treatment, Desalination, Membrane Technology, Emerging Contaminants, Sustainable Water Management.

Abstract: Accurate neutron flux and spectrum measurement are crucial for the operation and safety of nuclear reactors. This study reveals the effectiveness of neutron foil activation analysis for measuring neutron flux in the reactor core. The experiment successfully demonstrated the use of neutron foil activation analysis to measure neutron flux in a TRIGA research reactor. The experiment involved irradiating two gold (Au) samples, one unwrapped and one cadmium-wrapped at three different reactor power levels (50, 70, and 100 kW). The unwrapped sample interacted with a broader range of neutron energies, resulting in higher activity and flux compared to the wrapped sample. Specifically, at 50 kW, the unwrapped Au sample exhibited an activity 1.52E+06 disintegrations per second (dps) and a flux of 3.42E+09 neutrons per square centimetre per second (n/cm²s), whereas the wrapped sample had an activity of 4.49E+05 dps and a flux of 1.02E+09 n/cm²s. These measurements demonstrated a linear increase in count rate, activity, and neutron flux with increasing reactor power for the unwrapped sample, while the wrapped sample showed a non-linear trend due to the cadmium cover’s selective absorption of thermal neutrons.

Keywords: Neutron Flux, Gold Samples, Absorption

Abstract: Accurate modeling of lubricated joints, commonly referred to as journal bearings, in mechanical systems is essential for gaining a deeper understanding of machine dynamics. This is particularly important given the need for proper journal bearing design in many industrial applications. In this work, the incorporation of lubricated joint models into dynamical systems is examined. A general methodology is considered for modeling dynamically loaded journal bearings. The approach accounts for both squeeze-film and wedge-film effects. The governing equations of motion of mechanical systems incorporate the forces generated by lubrication effects. In journal bearing dynamic analysis, the hydrodynamic forces produced by the lubricant fluid, including squeeze and wedge effects, oppose the journal’s motion. The methodology applies the superposition principle by evaluating load capacity contributions from wedge entrainment and squeeze-film effects separately. Hydrodynamic forces are computed by integrating the pressure distribution obtained from Reynolds’ equation for dynamic conditions. These forces are nonlinear functions of the journal center’s kinematics relative to the bearing center. The present study employs Newton-Euler equations of motion and generalized Cartesian coordinates. Unlike an ideal revolute joint, a lubricated joint does not impose strict kinematic constraints but instead enforces force constraints. In practice, the hydrodynamic forces generated by the lubricant are evaluated from the system’s state variables and incorporated into the equations of motion. Finally, several mechanical systems are analyzed to illustrate the assumptions and procedures adopted. The results show that lubrication effects in mechanical joints can produce a predictable nonlinear dynamic response, a feature that plays a crucial role in the analysis, design, and control of general mechanical systems.

Keywords: Lubricated joints, Hydrodynamics approach, Dynamical Systems

Acknowledgements: (This work was supported by Fundação para a Ciência e a Tecnologia within the R&D units projects: UID/04436/2025 – Centro de Microssistemas Eletromecânicos of the University of Minho).

Abstract: Phosphoryl diazoalkanes are a class of important and useful reagents. They have been widely applied as synthetic building blocks in organic and medicinal synthesis. Aryl(diazo)methyl(diaryl)phosphine oxides are one class of phosphory diazomethanes. They reacted with aldehydes and ketones to generate benzo-δ-phosphinolactones, with α,β-enones to give rise to δ-phosphinolactones. When they reacted with cyclic imine dibenzo[b,e][1,4]oxazepines and dibenzo[b,e][1,4]thiazepines to yield corresponding polycyclic benzo-δ-phosphinolactams, while they produced β-phosphinolactams when they reacted with linear imines, especially α,β-enimines. When they reacted with 3-iminoindolinones, spiro β-phosphinolactams were obtained. However, when we prepared ethyl benzyl(diazomethyl)phosphinates from ethyl benzylphosphinochloridates and diazomethane, instead of ethyl benzyl(diazomethyl)phosphinates, ethyl poly(benzylphosphinates) were obtained and exhibited property of flame retardants.

Keywords: Carbene insertion, phosphinate, flame retardant, diazomethane, preparation

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Abstract: Lightweight Mg-Li alloys are promising structural materials, yet their strength is fundamentally limited by the anisotropy and detwinning susceptibility of conventional nanotwinned architectures. We recently demonstrated that a two-step high-pressure and high-temperature (HPHT) treatment can trigger a BCC-to-HCP martensite-like phase transformation in an Mg-9Li alloy, spontaneously generating triple-interlocked nanotwinned (TIT) networks with a twin boundary fraction of ~65.7% and an extraordinary yield strength of 508.6 MPa, accompanied by unprecedented ageing resistance (only 6% hardness loss after 730 days). The formation of TIT structures arises from the impingement of multiple {10-11} contraction twin variants under a tailored stress-temperature field, theoretically enabling the manipulation of twin types through external constraints.

Building on this TIT strategy, we propose a high-pressure-induced regulatory framework for Mg-Li-X (X = Sc, Y, Zn, Al, etc.) alloys, wherein the selection of X elements and the calibration of HPHT parameters (pressure 1~6 GPa, temperature 400~1200 °C) collectively govern the crystallographic orientation relationships, variant intersections, and ultimately the population of TIT configurations. The dissolution behavior and redistribution kinetics of X solutes at twin boundaries—analogous to the periodic Li segregation observed at {10-11} interfaces—are expected to further tailor the disclination dipoles at triple junctions, modulate the elastic stress fields, and stabilize the TIT networks. By establishing quantitative among composition, pressure, phase transformation dynamics, and twin architecture, this work aims to extend the TIT concept into a broad Mg-Li-X family, delivering a new class of ultra-strong, ageing-resistant, and anisotropy-free lightweight structural materials.

Keywords: High-pressure treatment, Mg-Li-X alloys, Mechanical properties, Triple-interlocked nanotwinned.

Abstract: Developments in robotics and electric mobility are currently advancing at a breathtaking pace. Humanoid robots now move with incredible speed and precision. This poses enormous challenges for the tribological systems incorporated into them. Tribological properties are system properties. The qualification of tribological systems is a complex process. The load spectrum of such systems is essentially defined by the combination of surface pressure and sliding velocity; in addition, parameters such as ambient temperature, surface properties of the system partners or component geometries play an important role. By modifying the plastics with various fillers, the reliable development of tribological pairings leads to a multidimensional investigation window with an almost unmanageable experimental effort.

A completely new approach that combines the innovative intelligent testing technology “TriboSmartControl (TSCon)” with artificial intelligence (AI) tools can efficiently and reliably determine the effects of a wide range of load spectra.

The talk highlights the relationships and mechanisms that have been explored over the past decades, but also the limitations of this approach for the targeted development of high-performance tribocomposites.

The talk shows that AI tools can make a decisive contribution to solving this issue. For example, artificial neural networks are superior to the human brain in pattern recognition. This can be useful in predicting tribological properties depending on a variety of loads. However, ANNs require a large amount of data as input, which can be achieved in a time and cost-efficient manner with the intelligent testing technology presented here.

Keywords: Tribology, high performance composites, artificial intelligence, intelligent testing.

Abstract: Rapidly developing science and technology demand new materials with versatile properties for practical applications. In this context, pseudo-octahedral iron(II) spin crossover (SCO) complexes are particularly appealing—not only for their fundamental scientific interest but also for their perspectives to be used in modern technologies and devices. This talk presents the synthesis and structure of a new mononuclear SCO complex [Fe^II(L)₂]⁰·nMeOH (n = 2, 0) where L is the asymmetrically substituted tridentate ligand [4-trifluoromethylphenyl-(1H-1,2,4-triazol-5-yl)-6-(1H-pyrazol-1-yl) pyridine], hereafter referred 4CF₃ (MeOH). The regular O_h geometry of the unsolvated form, 4CF₃, favors a complete spin transition (ST) at room temperature, which has been investigated, in the pressure interval 0–0.64 GPa. Contrary to experience, the increase of pressure on 4CF₃ denotes a radically abnormal behavior of this ST, involving: i) decrease of the characteristic temperatures, ii) increase of the high-spin molar fraction in the temperature range of the low-spin state; iii) above certain threshold pressure, full stabilization of the high-spin state. These observations have been explained in the framework of a thermodynamic model based on the elastic interactions.

Keywords: High pressure, spin transition, spin crossover, optical spectra, magnetic susceptibility.

Abstract: Accounting for rocking motion in structural design can enhance seismic resilience by improving a structure’s capacity to resist earthquake-induced loads. This study reviews the historical development of rocking motion analysis, addressing both methodological approaches and practical applications. Subsequently, a framework is presented for implementing the Discrete Element Method (DEM) to analyse the rocking behaviour of a rigid body using the open-source software Yade. The simplest and most economical approach - modelling the entire building as a clump of lumped masses has been adopted. The length of the building is assumed to be twice its width, and the number of stories - eight, which is typical for a Bulgarian reinforced concrete residential building. The model was subjected to three levels of ground motion with peak ground velocity (PGV) of up to 3.5 m/s along the width, while for each PGV level, a ground motion along the length of 50% the PGV or 100% the PGV was applied. A case without a ground motion along the length was also considered. In addition, the influence of the vertical component of ground motion acting together with the horizontal components was investigated. The rocking response of the building and its dependence on the intensity of ground motion were examined. The influence of the multi-directivity of ground motion on the rocking response was assessed in terms of the onset of rocking and the width of the separation gap.

Keywords: Rocking motion, rigid body, discrete element method

Abstract: The partial and full replacement of natural coarse aggregates (NCA) with coarse recycled concrete aggregates (CRCA) in the production of concrete helps preserve natural resources and energy and reduce the use of landfills. The shear resistance of concrete depends on aggregate interlock and can be affected by the less favorable properties of CRCA. This paper reports the results of an experimental program aimed at studying the effect of the percentage of replacement (PR) of NCA with CRCA on the shear strength of plain 50 MPa concrete based on pushoff tests. Thirty-nine pushoff specimens with PR of 0%, 10%, 20%, 50%, and 100% were cast from eight batches and tested under monotonic loading. Test results indicate that the increase in PR reduced the compressive strength and the pushoff shear strength of the concrete. However, the relation between the shear and the compressive strength was affected only in the concrete with high PRs.

Keywords: Concrete, modulus of elasticity, shear strength, recycled coarse aggregates.

Abstract: Carbon material with hierarchical structure prepared from sustainable resource-biomass has attracted more and more attention due to their promising potential for a wide applications as functional materials such as electric capacitor etc. Also, they could be used as environmentally friendly support and/or catalysts. The present study aims to develop novel methods to prepare diverse carbon materials with hierarchical structure using various templates and carbon resource. Furthermore, these carbon materials were utilized to prepare various carbon-based solid acid catalysts for saccharification of lignocellulosic biomass. (1) Using dual templates of poly-methyl-methacrylate (PMMA) and Pluronic-123, we synthesized a series of hierarchically structured macro-mesoporous carbon materials, and investigated the effect of PMMA loadings and the particle size, and carbon resource such as sucrose on the microstructural properties of the carbon material. Subsequently, we subjected this hierarchically structured carbon material to a sulfonation treatment to functionalize it as a solid acid catalyst; (2) Various metal oxides, such as Fe₃O₄, with different particle sizes were used as rigid templates to prepare lignin-derived carbon materials and/or catalysts, which were then sulfonated using concentrated sulfuric acid. We also investigated the effects of sulfonation conditions, such as temperature and time etc., on the microstructural properties of the carbon materials and/or catalysts. The porous structures of all the samples were characterized by using SEM, and N₂- adsorption-desorption measurement, and XRD. In addition, changes in surface functional groups were observed using FT-I and TEM. Finally, the catalytic performance of corresponding carbon-based solid acid catalyst was elucidated in the hydrolysis of cellulose and practical lignocellulosic biomass such as rice straw and corn stem etc. Based on the findings in the present study, a method for preparing carbon materials and solid acid catalysts with a novel hierarchical structure was established.

Keywords: Carbon material, hierarchical structure, solid acid catalyst, lignocellulosic biomass, saccharification.