Kristyna Kolouchova, Jana Humajova, Petr Matous
et al.
Abstract Photo-crosslinkable gelatin-based hydrogels hold great promise for tissue engineering and regenerative medicine. However, monitoring these hydrogels in vivo remains challenging and limits their further development and clinical translation. Here, we address this limitation by utilizing a gelatin-based hydrogel that incorporates the radiopaque compound 5-acrylamido-2,4,6-triiodoisophthalic acid (AATIPA). In an in vivo study spanning over 400 days, we monitor the degradation kinetics of these hydrogels using computed tomography and ultrasonography. We synthesize three distinct AATIPA-containing hydrogels and implant them subcutaneously into mice. Hydrogels with high crosslink density show minimal degradation, while those with lower crosslinking densities degrade within approximately three months. Histological evaluation reveals that the scaffolds are replaced by adjacent adipose tissue. In vitro, adipose-derived stem cells differentiate into the adipogenic lineage, corroborating the in vivo findings. These results highlight the potential of these hydrogels for adipose tissue engineering by enabling in vivo monitoring and offering tailored degradation profiles.
Materials of engineering and construction. Mechanics of materials
Fluid catalytic cracking is essential in petroleum refining but generates harmful silica-rich spent catalysts (CR). Agricultural waste, like burned rice husks, produces high-silica ashes (RHA). Both CR and RHA are promising waste-derived adsorbents. Polyurethane foams (PUFs) are ideal for adsorbing pesticides in water due to their multiple binding sites, making them effective supports for retaining various pesticide classes. Bio-based PUF was synthesized and incorporated with 50% CR or RHA by polyol mass. The sorbents were analyzed using X-ray diffraction, scanning electron microscopy, microtomography, thermogravimetric analysis, infrared spectroscopy, and contact angle. Effectiveness of the adsorbents in aqueous systems was evaluated by adsorption efficiency at different pHs (2.0, 7.0, and 12.0) using pesticides mancozeb, glyphosate, and 2,4-dichlorophenoxyacetic acid. In the experiment with mancozeb after 24 hours at pH 2.0 and a concentration of 300 mg L−1, pure PUF-REF obtained an adsorption efficiency of 85% (38.60 mg/g). In the same experiment, PUF loaded with CR achieved 98% (45.98 mg/g) removal of pesticide, while PUF loaded with RHA obtained adsorption efficiency of 62.5% (29.87 mg/g). This work examines the use of petrochemical and agro-industrial wastes as adsorbents for removing organic contaminants from natural waters, highlighting their potential to enhance sustainability and circular economy practices.
Materials of engineering and construction. Mechanics of materials
Martin Fally, Juergen Klepp, Christian Pruner
et al.
Photosensitive materials with ever-improving properties are of great importance for optical and photonics applications. Additionally, they are extremely useful for designing components for neutron optical devices. We provide an overview on materials that have been tested and successfully used to control beams of cold and very cold neutrons based on diffractive elements. Artificial gratings are generated and optimized for the specific application in mind. We discuss the needs of the neutron optics community and highlight the progress obtained during the last decade. Materials that have been employed so far along with their properties are summarized, outlining the most promising candidates for the construction of an interferometer for very cold neutrons.
The recent progress of using graph based encoding of crystal structures for high throughput material property prediction has been quite successful. However, using a single modality model prevents us from exploiting the advantages of an enhanced features space by combining different representations. Specifically, pre-trained Large language models(LLMs) can encode a large amount of knowledge which is beneficial for training of models. Moreover, the graph encoder is able to learn the local features while the text encoder is able to learn global information such as space group and crystal symmetry. In this work, we propose Material Multi-Modal Fusion(MatMMFuse), a fusion based model which uses a multi-head attention mechanism for the combination of structure aware embedding from the Crystal Graph Convolution Network (CGCNN) and text embeddings from the SciBERT model. We train our model in an end-to-end framework using data from the Materials Project Dataset. We show that our proposed model shows an improvement compared to the vanilla CGCNN and SciBERT model for all four key properties: formation energy, band gap, energy above hull and fermi energy. Specifically, we observe an improvement of 40% compared to the vanilla CGCNN model and 68% compared to the SciBERT model for predicting the formation energy per atom. Importantly, we demonstrate the zero shot performance of the trained model on small curated datasets of Perovskites, Chalcogenides and the Jarvis Dataset. The results show that the proposed model exhibits better zero shot performance than the individual plain vanilla CGCNN and SciBERT model. This enables researchers to deploy the model for specialized industrial applications where collection of training data is prohibitively expensive.
Large language models (LLMs) have rapidly gained popularity and are being embedded into professional applications due to their capabilities in generating human-like content. However, unquestioned reliance on their outputs and recommendations can be problematic as LLMs can reinforce societal biases and stereotypes. This study investigates how LLMs, specifically OpenAI's GPT-4 and Microsoft Copilot, can reinforce gender and racial stereotypes within the software engineering (SE) profession through both textual and graphical outputs. We used each LLM to generate 300 profiles, consisting of 100 gender-based and 50 gender-neutral profiles, for a recruitment scenario in SE roles. Recommendations were generated for each profile and evaluated against the job requirements for four distinct SE positions. Each LLM was asked to select the top 5 candidates and subsequently the best candidate for each role. Each LLM was also asked to generate images for the top 5 candidates, providing a dataset for analysing potential biases in both text-based selections and visual representations. Our analysis reveals that both models preferred male and Caucasian profiles, particularly for senior roles, and favoured images featuring traits such as lighter skin tones, slimmer body types, and younger appearances. These findings highlight underlying societal biases influence the outputs of LLMs, contributing to narrow, exclusionary stereotypes that can further limit diversity and perpetuate inequities in the SE field. As LLMs are increasingly adopted within SE research and professional practices, awareness of these biases is crucial to prevent the reinforcement of discriminatory norms and to ensure that AI tools are leveraged to promote an inclusive and equitable engineering culture rather than hinder it.
The stacking order and twist angle provide abundant opportunities for engineering band structures of two-dimensional materials, including the formation of moire bands, flat bands, and topologically nontrivial bands. The inversion symmetry breaking in rhombohedral-stacked transitional metal dichalcogenides (TMDCs) endows them with an interfacial ferroelectricity associated with an out-of-plane electric polarization. By utilizing twist angle as a knob to construct rhombohedral-stacked TMDCs, antiferroelectric domain networks with alternating out-of-plane polarization can be generated. Here, we demonstrate that such spatially periodic ferroelectric polarizations in parallel-stacked twisted WSe2 can imprint their moire potential onto a remote bilayer graphene. This remote moire potential gives rise to pronounced satellite resistance peaks besides the charge-neutrality point in graphene, which are tunable by the twist angle of WSe2. Our observations of ferroelectric hysteresis at finite displacement fields suggest the moire is delivered by a long-range electrostatic potential. The constructed superlattices by moire ferroelectricity represent a highly flexible approach, as they involve the separation of the moire construction layer from the electronic transport layer. This remote moire is identified as a weak potential and can coexist with conventional moire. Our results offer a comprehensive strategy for engineering band structures and properties of two-dimensional materials by utilizing moire ferroelectricity.
In Part I we constructed the Quantum Mechanics of a charged unitary entity and prescribed the form in which such a particle interacts with other charged particles and matter in general. In this second part we extend the description to the hydrogen atom testing the correctness and accuracy of the general description. The relation between electron and proton in the atom is described systematically in a construction that is free from analogies or ad-hoc derivations and it supersedes conventional Quantum Mechanics (whose equations linked to measurements can be recovered). We briefly discuss why the concept of isolation built in Schrödinger's time evolution is not acceptable and how it immediately results in the well known measurement paradoxes of quantum mechanics. We also discuss the epistemic grounds of the development as well as those of conventional Quantum Mechanics.
Michael A. Lively, Danny Perez, Blas Uberuaga
et al.
Radiation back-fluxes, generated from neutron-material interactions in fusion power reactors, can dramatically impact the plasma dynamics, e.g., by seeding runaway electrons during disruptions via Compton scattering of background electrons by wall-emitted gamma radiation. Here, we quantify these back-fluxes, including neutrons, gamma rays, and electrons, using Monte Carlo calculations for a range of structural material candidates and first wall thicknesses. The radiation back-flux magnitudes are remarkably large, with neutron and gamma radiation back-fluxes on the same order of magnitude as the incident fusion neutron flux. Electron back-fluxes are two orders of magnitudes lower, but are emitted at sufficiently high energies to provide a relatively large back-current through the sheath which may cause sheath reversal. Material configuration plays a key role in determining back-flux magnitudes. The structural material chiefly determines the neutron back-flux magnitude, while the first wall thickness principally attenuates the gamma ray and electron back-fluxes. In addition to prompt back-fluxes, which are emitted immediately after fusion neutrons impact the surface, significant delayed gamma ray and electron back-fluxes arise from nuclear decay processes in the activated materials. These delayed back-flux magnitudes range from 2%--7% of the prompt back-fluxes, and remain present during transients when fusion no longer occurs. During disruptions, build-up of delayed gamma radiation back-flux represents potential runaway electron seeding mechanisms, posing additional challenges for disruption mitigation in a power reactor compared with non-nuclear plasma operations. This work highlights the impact of these radiation back-fluxes plasma performance and demonstrates the importance of considering back-flux generation in materials selection for fusion power reactors.
Magnetic van der Waals (vdW) materials have attracted massive attention because of their academic interest and application potential for the past few years. Its main advantage is the intrinsic two-dimensionality, enabling much smaller devices of novel concepts. One particular exciting direction lies in the current-driven spin-orbit torque (SOT). Here, we, for the first time, realize an all vdW three-terminal SOT memory, employing the unique physics principle of gigantic intrinsic SOT of Fe3GeTe2 (FGT) and the well-known industry-adopted tunnelling magnetoresistance (TMR) effect. We designed the device operation procedure and fabricated the FGT/h-BN/FGT vdW heterostructure as a proof of concept. This device exhibits a classical TMR effect and unambiguously demonstrates the conception by precise performance as expected: the magnetic information of the top-FGT is written by current-driven SOT and read out by TMR separately. The writing and reading current paths are physically decoupled, enhancing the design and optimization flexibility substantially and further strengthening the device's endurance naturally. Our work would prompt more expansive use of vdW magnets for spintronic applications.
Hossein Taghinejad, Mohammad Taghinejad, Sajjad Abdollahramezani
et al.
Achieving deterministic control over the properties of low-dimensional materials with nanoscale precision is a long-sought goal. Mastering this capability has a transformative impact on the design of multifunctional electrical and optical devices. Here, we present an ion-assisted synthetic technique that enables precise control over the material composition and energy landscape of two-dimensional (2D) atomic crystals. Our method transforms binary transition metal dichalcogenides (TMDs), like MoSe$_2$, into ternary MoS$_{2α}$Se$_{2(1-α})$ alloys with systematically adjustable compositions, $α$. By piecewise assembly of the lateral, compositionally modulated MoS$_{2α}$Se$_{2(1-α)}$ segments within 2D atomic layers, we present a synthetic pathway towards the realization of multi-compositional designer materials. Our technique enables the fabrication of complex structures with arbitrary boundaries, dimensions as small as 30 nm, and fully customizable energy landscapes. Our optical characterizations further showcase the potential for implementing tailored optoelectronics in these engineered 2D crystals.
The paper presents the results of reverse engineering including metallographic, mechanical, and engineering-technical studies of used rods of a compressor produced by the Dresser-Rand company (Siemens, Germany). The study established that the original product is made of AISI 4140 steel with a working coating based on tungsten carbide applied to a depth of 0.2 mm by the HVOF method. The paper contains the results of the development of an import-substituting technological process for producing a wear-resistant powder coating of the Ni–Cr–B–WC system applied by cold gas flame spraying on the surface of a critical unit of compressor equipment in the oil and gas industry. Microanalysis identified that the sprayed spherical WC particles are evenly distributed in the nickel bond without the formation of free cavities at the lamella boundary, retain the size identical to the original powder composition upon the high-speed collision with the substrate, and minimize the level of residual mechanical stresses in the surface layer. The study shows that the sprayed coating has a high microhardness (the bases – 700 HV0.1, WC – up to 2000 HV0.1), which ensures high wear resistance during operation of the rod in a friction pair. A comparative analysis of the tribological properties of the coatings showed that when changing the shape, particle size distribution, and percentage ratio of tungsten carbide from 20 to 70 % in the nickel matrix, the overall wear resistance of the coating equivalently increases. The authors concluded on the possibility of manufacturing an import-substituting product using the gas flame spraying technology with metallurgical powder compositions containing tungsten. The authors developed an industrial technology for applying a wear-resistant coating on the working surface of a rod made of AISI 4140 steel. The paper presents the results of the analysis of the stress state of a material with a coating produced using the developed technology in comparison with the original product. In the product obtained by the experimental technology, in the process of applying the coating and its subsequent mechanical processing, uniform residual mechanical stresses are formed that do not exceed the value of the difference in the principal mechanical stresses. The paper presents the results of the study obtained both on standard samples and on a pilot part.
Materials of engineering and construction. Mechanics of materials
This paper presents a typical grasp–hold–release micromanipulation simulator based on MATLAB and Simulink. Closed-loop force and position control were implemented only based on a camera. The work was mainly focused on control performance improvements and GUI design. Different types of control strategies were investigated in both the position and force control processes. Finally, incremental PID and positional PID were adopted in the gripper position control and force control processes, respectively. The best performance of the gripper position control was the fast response of 0.3 s without overshoot and steady-state errors in the range of 10–40 Hz. The new camera control algorithm kept a big motion range (4.48 × 4.48 mm) and a high position resolution of 0.56 µm, with a high force resolution of 1.56 µN in the force control stage. The maximum error between the measured force and the real force was maintained below 4 µN. The steady-state error and the setting time were less than 1.2% and less than 1.5 s, respectively. A separate app, the Image Generation Simulator app, was developed to assist users in getting suitable initial coordinates, camera parameters, desired position resolutions, and force resolutions, which are packed as a standalone executable file. The main app can run the simulation model, debug, playback, and report simulation results, and calculate the calibration equation. Different initial coordinates, camera parameters, sample frequencies, controller parameters, and even controller types can be adjusted from this app.
Materials of engineering and construction. Mechanics of materials, Production of electric energy or power. Powerplants. Central stations
The slow regenerating rate and misdirected axonal growth are primary concerns that disturb the curative outcome of peripheral nerve repair. Biophysical intervention through nerve scaffolds can provide efficient, tunable and sustainable guidance for nerve regrowth. Herein, we fabricate the reduced graphene oxide (rGO)/polycaprolactone (PCL) scaffold characterized with anisotropic microfibers and oriented nanogrooves by electrospinning technique. Adipose-derived stem cells (ADSCs) are seeded on the scaffolds in vitro and the viability, neural differentiation efficiency and neurotrophic potential are investigated. RGO/PCL conduits reprogram the phenotype of seeded cells and efficiently repair 15 mm sciatic nerve defect in rats. In summary, biophysical cues on nerve scaffolds are key determinants to stem cell phenotype, and ADSC-seeded rGO/PCL oriented scaffolds are promising, controllable and sustainable approaches to enable peripheral nerve regeneration.
Materials of engineering and construction. Mechanics of materials, Biology (General)
Machine learning (ML) components are being added to more and more critical and impactful software systems, but the software development process of real-world production systems from prototyped ML models remains challenging with additional complexity and interdisciplinary collaboration challenges. This poses difficulties in using traditional software lifecycle models such as waterfall, spiral, or agile models when building ML-enabled systems. In this research, we apply a Systems Engineering lens to investigate the use of V-Model in addressing the interdisciplinary collaboration challenges when building ML-enabled systems. By interviewing practitioners from software companies, we established a set of 8 propositions for using V-Model to manage interdisciplinary collaborations when building products with ML components. Based on the propositions, we found that despite requiring additional efforts, the characteristics of V-Model align effectively with several collaboration challenges encountered by practitioners when building ML-enabled systems. We recommend future research to investigate new process models, frameworks and tools that leverage the characteristics of V-Model such as the system decomposition, clear system boundary, and consistency of Validation & Verification (V&V) for building ML-enabled systems.
Jakub Polaczyński, Gauthier Krizman, Alexandr Kazakov
et al.
$α$-Sn is an elemental topological material, whose topological phases can be tuned by strain and magnetic field. Such tunability offers a substantial potential for topological electronics. However, InSb substrates, commonly used to stabilize $α$-Sn allotrope, suffer from parallel conduction, restricting transport investigations and potential applications. Here, the successful MBE growth of high-quality $α$-Sn layers on insulating, hybrid CdTe/GaAs(001) substrates, with bulk electron mobility approaching 20000 cm$^2$V$^{-1}$s$^{-1}$ is reported. The electronic properties of the samples are systematically investigated by independent complementary techniques, enabling thorough characterization of the 3D Dirac (DSM) and Weyl (WSM) semimetal phases induced by the strains and magnetic field, respectively. Magneto-optical experiments, corroborated with band structure modeling, provide an exhaustive description of the bulk states in the DSM phase. The modeled electronic structure is directly observed in angle-resolved photoemission spectroscopy, which reveals linearly dispersing bands near the Fermi level. The first detailed study of negative longitudinal magnetoresistance relates this effect to the chiral anomaly and, consequently, to the presence of WSM. Observation of the $π$ Berry phase in Shubnikov-de Haas oscillations agrees with the topologically non-trivial nature of the investigated samples. Our findings establish $α$-Sn as an attractive topological material for exploring relativistic physics and future applications.
Two artificial neural networks (ANNs) were developed for producing an austempered ductile iron (ADI) with low-cost chemical composition and mechanical properties as per ASTMA897/897M-16-grade-1050/750/07 standard. Thus, the first ANN predicted the chemical composition range within the lowest cost and required mechanical properties. Next, in the second ANN, the resulting values from the first ANN were refined considering the target chemical composition suggested in the standard. Moreover, mechanical properties and microstructural analyses were undertaken in the ADI produced to support the ANNs’ findings. Hence, ANNs can be used to make a standard-compliant ADI and achieve cost savings.
Materials of engineering and construction. Mechanics of materials
Abstract In the field of proton exchange membranes (PEMs), it is still a great challenge to explore new Nafion alternatives, maintaining the high proton conductivity and lowering the cost of practical application. In this work, a series of low sulfonated poly(aryl ether ketone sulfone) (SPAEKS) membranes hybridized by [Bi6O5(OH)3]2(NO3)10·6H2O (H6Bi12O16) have been successfully fabricated. When the doping amount of H6Bi12O16 reaches 5 wt%, the DS15‐Bi12‐5 showing the best proton conductive ability and mechanical properties. The proton conductivity can achieve 72.8 mS·cm−1 at 80°C and the tensile strength can reach 43.57 MPa. Confirmed by experimental data and activation energy (Ea) calculations, the existence of Bi cluster makes more hydrogen bonds, providing additional proton hopping sites and offers more proton transport vehicles, leading to a high proton conduction performance. This work proved that polyoxometalates (POMs) can replace the role of sulfonate groups in SPAEKS to a certain extent and work out the defects of high sulfonation, making a remarkable contribution to the practical application of low sulfonated SPAEKS.
Materials of engineering and construction. Mechanics of materials, Environmental engineering
Lorenz Graf-Vlachy, Daniel Graziotin, Stefan Wagner
Context: Citations are a key measure of scientific performance in most fields, including software engineering. However, there is limited research that studies which characteristics of articles' metadata (title, abstract, keywords, and author list) are driving citations in this field. Objective: In this study, we propose a simple theoretical model for how citations come to be with respect to article metadata, we hypothesize theoretical linkages between metadata characteristics and citations of articles, and we empirically test these hypotheses. Method: We use multiple regression analyses to examine a data set comprising the titles, abstracts, keywords, and authors of 16,131 software engineering articles published between 1990 and 2020 in 20 highly influential software engineering venues. Results: We find that number of authors, number of keywords, number of question marks and dividers in the title, number of acronyms, abstract length, abstract propositional idea density, and corresponding authors in the core Anglosphere are significantly related to citations. Conclusion: Various characteristics of articles' metadata are linked to the frequency with which the corresponding articles are cited. These results partially confirm and partially go counter to prior findings in software engineering and other disciplines.
Aiming at the low detection rate of the existing classroom attendance system and the inconvenience of data query, a non-perceptual classroom attendance system based on face recognition is proposed and designed. Using the Android development platform, the image collected by the front-end was first transferred to the server through OkHttp3 technology. Then the information of the class in the database MySQL was retrieved. Then the face image of each student was filtered through the improved Fust face detection algorithm, and the similarity value within the class and similarity value between the class generated VIPLFaceNet face recognition threshold, which recognized the screened face images and obtained the attendance result. Finally, the attendance result was sent to the front end, the administrator could access the server to query attendance data. The experimental results showed that the recall rate of the improved Fust face detection algorithm and the recognition rate of the VIPLFaceNet face recognition algorithm could reach 90.18% and 98.79% respectively.
Materials of engineering and construction. Mechanics of materials, Environmental engineering