Search Results (6,135)

Friction-spinning is an incremental thermomechanical forming process that has huge potential due to its simple yet effective mechanism of utilising friction between a rotating workpiece and a forming tool to increase the workpiece’s temperature, which reduces the required forces and increases formability during the forming process. Despite the simplicity of the process’s setup, the thermomechanical loads and high relative velocities involved, especially in the contact zone, make the application of classical methods for characterising friction inaccurate. It is therefore essential to find a way to describe the frictional behaviour under real process conditions to be able to gain a holistic understanding of the process and the effect of the adjustable parameters on the outcome, especially the temperature. To achieve this goal, an experimental setup that considers the actual process boundary conditions in forming tubes made of EN AW-6060 was used to measure in situ normal and frictional forces, in addition to process temperatures, under varying rotational speed and feed rate values. Full article

Hybrid thermosetting terpolymers based on epoxidized linseed oil (ELO), eugenol-based benzoxazine monomer (EPB), and thiols (2SH and 3SH) were synthesized and studied by focusing on the effects of the thiol-bearing functionality over the final performances. The curing dynamics were monitored by differential scanning calorimetry (DSC) and Fourier transform infrared spectrometry (FTIR). FTIR results showed that the curing process takes place in multiple steps and depends on the concentration of thiol used as a crosslinker. At the same time, the complexity of the reactions that take place within each system was highlighted by the curing profiles from DSC. Dynamic mechanical analysis (DMA) and nanoindentation data revealed that the mechanical features of the terpolymers can be modulated to achieve high stiffness, as in the case where 2SH and 3SH thiols were used in 0.25 wt.% or increased flexibility where 1% thiol concentrations were employed. Higher crosslinking density for hybrid terpolymers in comparison with the epoxy/benzoxazine sample indicated a good compatibility between the monomers and the crosslinking agents and the formation of additional chemical bonds within the networks. The ternary samples demonstrated good thermal stability (up to 300 °C) and high residual mass (>25%), which make them suitable candidates as flame-resistant coatings. Full article

Accurate estimation of multiaxial fatigue life plays a critical role in maintaining the structural integrity and operational reliability of mechanical components subjected to complex loading conditions. Under non-proportional loading, fatigue life tends to decrease significantly due to the emergence of additional damage mechanisms, such as dislocation accumulation, cyclic hardening, and accelerated propagation of micro-cracks. This study conducts a systematic investigation into the primary factors that influence fatigue behavior under non-proportional loading conditions. A novel damage factor is proposed, which quantifies the additional strengthening effects caused by complex stress and strain interactions. Based on this factor, a new prediction model is developed through the combination of critical plane theory and an energy-based framework. This model captures the influence of non-proportional strengthening on fatigue strength with improved accuracy. Experimental validation is carried out using En8, TC4, and Al7050-T7451 materials under tension and torsion loading conditions. Comparative analysis with three conventional models shows that the proposed method improves the accuracy of predictions and offers a dependable approach for practical engineering applications. Full article

The aim of the study was to use vacuum impregnation (VI) with onion and beetroot juices as a pre-treatment before drying to develop innovative dried kohlrabi products. Two modern drying techniques were used: freeze-drying (FD) and vacuum drying (VD). The physicochemical properties were determined, including color, water activity, dry matter, density, volumetric gel index, texture, antioxidant capacity, total phenolic content (TPC), and volatile organic compounds (VOCs). It was shown that vacuum impregnation reduced the color lightness and springiness of kohlrabi. In addition, vegetables after VI showed an increase in dry matter, water activity, bulk density, volume gel index, color attributes a* and b*, color difference, hardness, and chewiness. Furthermore, the pre-treatment allowed for the introduction of additional VOCs characteristic of onions (1-Heptene, 2-methyl-(19.81%), Pentyl formate (19.81%), and 4-(Methylthio)butyl isothiocyanate (18.22%) in kohlrabi with onion juice: dimethyl trisulfide, methyl prop(en)yl disulfide, and 3,5-diethyl-1,2,4-trithiolane) and beetroot (dimethyl trisulfide), myrcene. The vacuum impregnation process significantly increased antioxidant capacity and total polyphenol content compared to raw samples. The results of dry weight, water activity, density, TPC, antioxidant capacity and texture in the case of freeze-dried products confirm that FD is a more advantageous method. In addition, freeze-drying allowed for significant preservation of volatile compounds and the color of kohlrabi. The results indicate the potential of VI as a method for modifying the properties of kohlrabi and producing functional and innovative dried products. Full article

This article discusses the current requirements for laboratory testing of the fire properties of seating in railway vehicles and the criteria for their assessment. The results of flammability and smoke tests performed on selected passenger seats and samples of the upholstery systems used in their construction are presented in order to find connections between them. It was demonstrated that the composition of the upholstery fabric has a significant impact on the burning behavior of the seats and the upholstery systems themselves, assuming that the same foam was used in their construction. Based on the conducted research, material composition analysis, and results, a lack of correlation was also found between the results of tests using a cone calorimeter and a furniture calorimeter. This confirms that the fire properties of upholstered products depend on many factors, including composition, shape, materials used, type of upholstery, and the design solutions of the finished seats. The tested upholstered products intended for railway applications are characterized by stochastic variability resulting from their specific applications and functional and operational properties. Full article

The electrochemical oxidation of anodic metal (cobalt, nickel, zinc or cadmium) in a cell containing an acetonitrile solution of the ligand (E)-N-(2-(((2-hydroxynaphthalen-1-yl)methylene)amino)phenyl)-4-methylbenzenesulphonamide (H₂L) affords complexes with the general formula [ML] (M = Co, Ni, Zn and Cd). Additionally, it was possible to obtain complexes with the general formula [MLL′] when L′ = 2,2-bipyridine (2,2-bpy), 4,4-bipyridine (4-4′-bpy) or 1,10-phenanthroline (phen) was present in the electrolytic cell. All of the compounds obtained have been characterized via microanalysis, IR spectroscopy, mass spectrometry, UV–visible spectroscopy and, in the case of diamagnetic compounds, via ¹H NMR spectroscopy. Further structural and electronic characteristics of these adducts have been obtained via DFT simulations. The compounds NEt₄[CoL₂] (1), [NiL(H₂O)] (2), [NiL(CH₃CN)(H₂O)]₂ (3), [Ni₂L₂(4,4′-bpy)] (4), [Zn₂L₂(MeOH)₂] (5) and [ZnL(2,2′-bpy)](CH₃CN) (6) have been characterized via X-ray diffraction. In this paper, we present a detailed study of the different behavior of the above-mentioned ligand depending on the metal and/or the presence of ancillary ligands. Full article

Background: Rectal neuroendocrine tumors (NETs) ≤ 10 mm are commonly managed by endoscopic resection. However, the optimal technique remains controversial. We aimed to compare the efficacy and safety of a simplified endoscopic mucosal resection (sEMR) technique, performed without submucosal injection, with conventional endoscopic submucosal dissection (ESD) for small rectal NETs. Methods: This retrospective, single-center study included 74 patients with histologically confirmed rectal NETs ≤ 10 mm treated with sEMR (n = 37) or ESD (n = 37) between January 2022 and January 2025. Patients in the ESD group were matched 1:1 by age and gender. Baseline characteristics, procedural outcomes, histopathologic findings, and cost were analyzed. The primary outcome was histological complete resection (R0) rate; secondary outcomes included en bloc resection, intraoperative bleeding, tumor-to-margin distance, operation time, and material costs. Results: The R0 resection rate was significantly higher in the sEMR group compared to the ESD group (91.9% vs. 67.6%; p = 0.019). Tumor-to-margin distance was also significantly greater in the sEMR group [median (IQR): 0.2 (0.1–0.3) mm vs. 0.1 (0–0.2) mm; p = 0.024]. Intraoperative bleeding was less frequent in the sEMR group (2.7% vs. 21.6%; p = 0.028). Median operation time (409 vs. 1469 s; p < 0.001) and material cost (1486 vs. 6390 CNY; p < 0.001) were both significantly lower in the sEMR group. Conclusions: Compared with ESD, the simplified EMR technique without submucosal injection demonstrated higher R0 resection rates, lower bleeding risk, shorter operation time, and lower costs for small rectal NETs. sEMR may offer a safe, efficient, and cost-effective alternative in selected patients. Full article

Aluminum is widely used in many industries like automotive, aerospace and construction because of its low weight, good mechanical strength and resistance to corrosion. This resistance comes mainly from a passive oxide layer that forms on its surface. However, when aluminum is exposed to harsh environments, especially those containing chloride ions in marine environments, this layer can break down and lead to localized corrosion, such as pitting. This study examined aluminum profiles at different processing stages, including homogenization and aging, anodizing and pre-anodizing followed by painting. Corrosion behavior of samples was studied using two electrochemical methods. Potentiodynamic polarization was used to measure corrosion rate and current density, while Electrochemical Impedance Spectroscopy (EIS) helped to understand the behavior of protective layers and corrosion progression. Tests were carried out in a 3.5% NaCl solution at room temperature. EIS results were analyzed using equivalent circuit models to better understand electrochemical processes. Overall, this study shows how surface treatment affects corrosion resistance and highlights advantages of EIS in studying corrosion behavior in a more reliable and repeatable way. Full article

This paper presents the development of two mobile brain Positron Emission Tomography (PET) scanners under the PETITION project, designed for Intensive Care Units (ICUs) and Proton Beam Therapy (PBT) applications. The ICU scanner facilitates bedside imaging for critically ill patients, while the PBT scanner enables undisturbed proton beam irradiation during imaging. Key aspects of the hardware design, including modular detectors and electromagnetic interference considerations, are discussed along with preliminary performance evaluations. Operational testing, employing a ²²Na source and a hot-rod phantom, was conducted to determine the timing resolution (548 $\mathrm{p}$$\mathrm{s}$), energy resolution (11.4%) and a qualitative spatial resolution (around 2.2 $\mathrm{m}$$\mathrm{m}$). Our study presents findings on the ICU PET scanner’s electromagnetic emissions measured in a controlled EMC testing facility, where all the emissions tests performed comply with the standard EN 60601-1-2 (radiated emissions 15 dB below regulatory limits in the frequency range of 30 $\mathrm{M}$$\mathrm{Hz}$ to 1 G$\mathrm{Hz}$). Full article

Background/Objectives: Constipation can be induced in animal models through various factors such as loperamide (Lop) or complement component 3 (C3) deficiency. The effectiveness of therapeutic agents in the clinical management of constipation has been primarily evaluated within only one model, but between-model comparisons have not been performed so far. Therefore, we investigated whether the effectiveness of the laxative drugs for the clinical management is related to etiological factors. Methods: The changes in the key parameters for defecation were compared between C3 knockout (KO) mice with C3-deficiency-induced constipation and ICR mice with Lop-induced constipation after the oral administration of Uridine (Urd) and aqueous extract of Liriope platyphylla L. (AELP). Results: Similar effectiveness of Urd and AELP were detected on the stool frequency, intestinal epithelial barrier structure, and mucin secretion in both models. However, other parameters (namely gastrointestinal (GI) transit, water retention, and enteric nervous system (ENS) structure and function) showed higher effectiveness in C3 KO mice than in the Lop-induced model. Only the effectiveness of the two therapeutic agents on the histological structure of the mid-colon was greater in the Lop-induced mice model compared to the C3 KO mice model. Furthermore, these differences in the therapeutic effectiveness of Urd and AELP were partially reflected in alterations in the cyclic adenosine monophosphate (cAMP) downstream signaling pathway. Conclusions: The results suggest that the therapeutic effectiveness of Urd and AELP is sensitive to C3-deficiency-induced constipation and these differences may be linked to the alternative regulation of the cAMP downstream signaling. Full article

Ferrite grain size strengthening makes the predominant contribution to the overall strength of ferrite–pearlite structural hollow section steel grades. A fine ferrite grain size is achieved through a two-stage controlled cooling process. First, the material is rapidly cooled with water. This provides a large undercooling, which is the driving force for ferrite to form. The second stage involves slow natural (air) cooling, where the cooling rates and the transition temperature from water to air cooling are carefully controlled. This is crucial to prevent the formation of bainite or martensite. Ferrite grain sizes can be predicted for continuous cooling and isothermal transformation based on the prior austenite grain size, composition and cooling rate/isothermal transformation temperature. However, predictions for multiple-cooling-stage transformations have not been reported. In this work, EN S355-grade steel was used to study ferrite grain size development during continuous cooling, isothermal holding and complex (two-stage or multi-stage) cooling. Dilatometry and microstructure assessment was used to study the relationship between the final ferrite grain size and undercooling at which 40% of the ferrite formed. It was found that any changes in cooling rate/temperature (including a possible ‘bounce back’ in temperature due to latent heat formation) after 40% of the ferrite had formed had a negligible effect on the final ferrite grain size, assuming that re-austenitization or bainite formation was avoided. Full article

Objectives: This study aimed to examine the effects of a personalized exercise program on muscle functional capacity and daily life activities among individuals of various age groups and health conditions. Methods: A total of 169 participants aged between 16 and 94 years with varying health statuses were enrolled. The EN-Dynamic system—comprising progressive resistive exercise equipment and Enraf Nonius’ Entrack software—was utilized alongside a newly developed exercise programming software. Maximum functional capacity was measured across 13 distinct muscle groups for each participant. Four different questionnaires were administered pre-intervention to evaluate daily activity levels and disease severity. Based on the collected data, a personalized exercise program was generated using a mathematical formula tailored to each muscle group. The program was applied three times per week for 12 weeks (36 total sessions). Following the intervention, the same measurements and questionnaires were repeated and analyzed statistically. Results: Data were analyzed using t-test, one-way ANOVA, Pearson correlation analysis, and Bonferroni post hoc tests. A statistically significant improvement in muscle functional capacity was found (t(168) = −30.65, p < 0.01; 95% CI: [16.95, 19.31]; Cohen’s d = 2.35, very large effect size). The questionnaire results also demonstrated substantial reductions (e.g., t(168) = 18.51, p < 0.01; Cohen’s d = 1.42). Conclusions: These findings suggest that personalized exercise programs can significantly enhance muscle functional capacity while reducing psychological and physical stress and disease severity. Nonetheless, further controlled and longer-term clinical trials comparing traditional and personalized methods are required to confirm these benefits at the population level. Full article

The metropolitan agglomeration in and around Bucharest, Romania’s capital and largest city, has experienced significant growth in recent decades, both economically and demographically. With over two million residents in its metropolitan area, Bucharest faces urban mobility challenges characterized by congested roads, overcrowded public transport routes, limited parking, and air pollution. This study evaluates the potential of AI-driven adaptive traffic signal control to address these challenges using an agent-based simulation approach. The authors focus on Bucharest’s north-western part, a critical congestion area. A detailed road network was derived from OpenStreetMap and calibrated with empirical traffic data from TomTom Junction Analytics and Route Monitoring (corridor-level speeds and junction-level turn ratios). Using the MATSim framework, the authors implemented and compared fixed-time and adaptive signal control scenarios. The adaptive approach uses a decentralized, demand-responsive algorithm to minimize delays and queue spillback in real time. Simulation results indicate that adaptive signal control significantly improves network-wide average speeds, reduces congestion peaks, and flattens the number of en-route agents throughout the day, compared to fixed-time plans. While simplifications remain in the model, such as generalized signal timings and the exclusion of pedestrian movements, these findings suggest that deploying adaptive traffic management systems could deliver substantial operational benefits in Bucharest’s urban context. This work demonstrates a scalable methodology combining open geospatial data, commercial traffic analytics, and agent-based simulation to rigorously evaluate AI-based traffic management strategies, offering evidence-based guidance for urban mobility planning and policy decisions. Full article

Background/Objectives: GaBHA syndrome (gastric bypass hyperammonemia) is an emerging new syndrome primarily in women who had prior Roux-en-Y gastric bypass surgery (RYGB) and then developed non-cirrhotic hyperammonemia with a high case–fatality ratio. Genetic and nutritional deficiencies have been implicated in the pathogenesis of this clinical condition, but none has been proven. We present an illustrative case and do a scoping review of the current literature in 58 patients with this diagnosis. Methods: A retrospective scoping literature review was utilized to identify patients who fulfilled 1. RYGB surgery, and 2. Hyperammonemic encephalopathy following the PRISMA extended checklist. We searched PubMed, MedLine, SCOPUS, and Web of Science databases. Results: We described the classic presenting symptoms and laboratory findings of this syndrome. We confirmed the female predominance (93%) and the high case–fatality ratio (32%). We then presented a novel hypothesis contending that arginine deficiency ultimately leads to a functional deficiency of the ornithine transcarbamolyase (OTC) enzyme, leading to the non-cirrhotic life-threatening hyperammonemia. Our hypothesis may also explain the high incidence of hypoglycemia found in these patients as we found in our search. Our proposed hypothesis may also be relevant to the occurrence of hyperammonemia in some solid organ transplant recipients. Conclusions: GaBHA syndrome is emerging as an important potential adverse outcome after RYGB surgery. It has a female predominance and a high case–fatality ratio. Arginine deficiency may explain the emergence of a functional OTC deficiency, which then leads to the severe hyperammonemia, and may also explain the frequent occurrence of hypo-glycemia in these patients. Full article

The increasing power demand in substations and the advancement of smart-grid technology point to optical voltage sensors (OVSs) based on the Pockels effect as an attractive solution to replace traditional coil instrument transformers, due to their advantageous characteristics of lower cost and installation space, absence of explosion risks, as well as nonlinear effects such as magnetic hysteresis. Regarding the measurement, our OVS presents excellent linearity, 3 kHz bandwidth, and high input impedance. The primary contribution of this paper is to demonstrate, for the first time, the efficiency of a versatile nonlinear digital controller, based on sliding mode theory, for the optical phase demodulation of an OVS. A simple proportional-integral feedback control is employed to prevent signal fading and generate the two quadrature signals required by the observer, which includes the nonlinear digital controller. Experimental results, for 60 Hz sinusoidal voltages with amplitudes exceeding the half-wave voltage of the OVS, prove that peak-to-peak relative errors remain below 0.8%, while total harmonic distortion (THD) relative errors are under 1.5% when compared to a commercial high-voltage probe used as a reference. These results confirm compliance with Class 1.0 of the UNE-EN 60044-7 standard and show strong potential for applications in power quality measurements. Full article