Search Results (369)

To address the growing need for sustainable and resilient building materials, the seismic performance of a full-scale moment-frame housing system constructed entirely from recycled Tetra Pak panels (thermo-stiffened polymeric aluminum or TSPA) was evaluated. The study presents an innovative approach to utilizing waste materials for structural applications, emphasizing the lightweight and modular nature of the system. The methodology included material characterization, finite element modeling (FEM), gravitational loading tests, and biaxial shake table tests. Seismic tests applied ground motions corresponding to 31-, 225-, 475-, and 2500-year return periods. Drift profiles and acceleration responses confirmed the elastic behavior of the system, with no residual deformation or structural damage observed, even under simultaneous peak ground accelerations of 0.37 g (x-direction) and 0.52 g (y-direction). Notably, the structure accelerations were amplified to 1.10 g in the y-direction (at the top of the structure), exceeding the design spectrum acceleration of 0.7 g without compromising stiffness or resistance. These results underscore the robust seismic performance of the system. The finite element model of the housing module was validated with the experimental results which predicted the structural response, including natural periods, accelerations, and drift profiles (up to 89% accuracy). The novelty of this research is that it is one of the first to perform shaking table seismic testing on a full-scale housing module made of recycled materials (Tetra Pak), specifically under biaxial motions, providing a unique evaluation of its performance under multidirectional seismic demands. This research also highlights the potential of recycled Tetra Pak materials for sustainable construction, providing an adaptable solution for earthquake-prone regions. The modular design allows for rapid assembly and disassembly, supporting scalability and the circular economy principle. Full article

The use of 3D roughness parameters is increasingly gaining ground in various areas of engineering, especially in academic research. In many cases, however, these studies primarily cover the illustration of the character of the surfaces, the interpretation of areal numerical roughness values is often disputed. The goal of this paper is to examine how the 2D and 3D roughness parameters change in the case of anisotropic surfaces, such as surfaces cut with an abrasive water jet. For this purpose, abrasive water jet cutting experiments were performed on AlMgSi0.5 aluminum alloy using different technological parameters. After the experiments, two amplitude-type 3D roughness parameters (S_a and S_z) of the cut surface and four profile parameters (R_a, R_z for roughness and P_a, P_z for raw profile) were measured at five different depths. Our conducted research indicates that the 3D parameters represent a kind of average value for certain roughness characteristics and a maximum value for others. The paper also reports on how these roughness characteristics change as a function of feed speed. Full article

In the cold chamber high pressure die casting process (CC-HPDC) for light alloys, the piston lubricants play a key role in protecting the piston tip from wearing and ensure adequate seal with the shot sleeve. However, during the production process, the pouring of overheated aluminum alloy melt into the shot sleeve would lead to evaporation and burning of the lubricants once in contact with the piston tip. The burning products, however, would form gas and non-metallic inclusions in the melt which would be transported and injected into the die area and finally trapped in the castings, all of which would affect the mechanical properties of the as-cast samples and deteriorate the product quality. To further investigate this issue, a pilot scale HPDC machine is used and the lubricant burning issue is studied based on material characterization and numerical modelling. The chemical composition, size, and morphology of the burned products are observed using scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). In order to better explore the issue of lubricant combustion discovered in the experiment, a finite element model describing the entire HPDC process is established and the burning, motion, and trapping of the lubricant are calculated. The final distribution of the burned products such as gas and non-metallic inclusions are predicted and their influence on final solidification quality of the as-cast products under various process parameters are analyzed qualitatively. Finally, a slow shot velocity range of 0.4–0.6 m/s and an acceleration profile that ramps up to 0.3 m/s over 0–370 mm of the shot sleeve proved to be the most effective in reducing air entrainment and oxide inclusions to alleviate the burning of lubricant on final product quality. Full article

Stroke affects approximately 12 million individuals annually, necessitating swift diagnosis to avert fatal outcomes. Current hospital imaging protocols often delay treatment, underscoring the need for portable diagnostic solutions. We have investigated silver nanostars (AgNS) incubated with human plasma, deposited on a simple aluminum foil substrate, and utilizing Surface-Enhanced Raman Spectroscopy (SERS) combined with machine learning (ML) to provide a proof-of-concept for rapid differentiation of stroke types. These are the seminal steps for the development of low-cost pre-hospital diagnostics at point-of-care, with potential for improving patient outcomes. The proposed SERS assay aims to classify plasma from stroke patients, differentiating hemorrhagic from ischemic stroke. Silver nanostars were incubated with plasma and spiked with glial fibrillary acidic protein (GFAP), a biomarker elevated in hemorrhagic stroke. SERS spectra were analyzed using ML to distinguish between hemorrhagic and ischemic stroke, mimicked by different concentrations of GFAP. Key innovations include optimized AgNS–plasma incubates formation, controlled plasma-to-AgNS ratios, and a low-cost aluminum foil substrate, enabling results within 15 min. Differential analysis revealed stroke-specific protein profiles, while ML improved classification accuracy through ensemble modeling and feature engineering. The integrated ML model achieved rapid and precise stroke predictions within seconds, demonstrating the assay’s potential for immediate clinical decision-making. Full article

Hybrid PVT systems simultaneously produce electrical energy using photovoltaic technology and thermal energy using a heat extraction method that collects induced heat from the module. The purpose of this work is to establish a PVT system based on characterization, efficiency study, and performance analysis for both an electrical and a thermal system. A mathematical analysis of the electrical, thermal, and optical model is performed to establish the proposed system. Three types of heat exchanger pipes, including stainless steel, aluminum, and copper, are considered for a heat transfer analysis of the system. The results include temperature profiling, a comparison of the PVT system’s different components, and an overall output and efficiency study for all of the mentioned pipes. Results show that the obtained electrical and thermal efficiency for stainless steel is 0.1653 and 0.237, respectively, for aluminum it is 0.16515 and 0.2401, respectively, and for copper it is 0.16564 and 0.24679, respectively. After comparison, it was found that the overall efficiency for stainless steel is 0.40234, for aluminum is 0.40526, and for copper is 0.41244. Thus, this study will enhance the opportunity to provide an effective hybrid PVT energy management system. Full article

This study investigates the content of some metals and metalloids in the flowers of three Aesculus cultivars (AHP, Aesculus hippocastanum pure species, with white flowers; AHH, Aesculus hippocastanum hybrid species, with pink flowers; and AXC, Aesculus × carnea, with red flowers) over a four-year period (2016–2019) using inductively coupled plasma optical emission spectrometry (ICP OES) and principal component analysis (PCA). The research focuses on assessing macro- and micro-elemental compositions, identifying variations in mineral uptake, and exploring potential correlations with soil composition. Results highlight significant differences in elemental profiles among the three species, despite similar total ash content. Potassium and phosphorus emerged as dominant macroelements, with AXC showing lower magnesium levels compared to AHP and AHH. Particularly intriguing was the detection of antimony in all cultivars, raising questions about its role and bioaccumulation pathways in floral tissues. Iron and aluminum concentrations varied significantly across species, indicating species-specific metal transport mechanisms. Nickel content showed temporal fluctuations, potentially influenced by climatic conditions and soil properties. PCA revealed distinct clustering patterns, linking elemental concentrations to specific species and years. This comprehensive analysis enhances understanding of metal absorption and distribution in ornamental plants, providing insights into their metabolic processes and potential implications for environmental monitoring and phytoremediation strategies. Full article

A novel method to measure dynamic flow stress and corresponding strain rates obtained from Taylor tests using profiled samples with a reduced cylindrical head part was applied to study the dynamic characteristics of similar commercial 7075 and V95T1 aluminum alloys. The measured dynamic flow stress is verified using a classical Taylor’s approach with uniform cylinders and compared with the literature data. Our study shows that the dynamic flow stress of 7075 alloy, which is 786 MPa at strain rates of (4–8) × 10³ s⁻¹, exceeds the value of 624 MPa for V95T1 alloy at strain rates of (2–6) × 10³ s⁻¹ by 25%. The threshold impact velocity resulting in fracture of the 4 mm head part of the profiled samples is 116–130 m/s for 7075 alloy and only 108 m/s for V95T1 alloy. The fracture pattern is also different between the alloys with characteristic shear-induced cracks oriented at 45° to the impact direction in the case of V95T1 alloy and perpendicular to the breaking off head part in the case of 7075 alloy. On the other hand, the compressive fracture strain of V95T1 alloy, which is 0.29–0.36, exceeds that of 7075 alloy, which is 0.27–0.33, by approximately 8%. Thus, V95T1 aluminum alloy exhibits less strength but is more ductile, while 7075 aluminum alloy exhibits more strength but is simultaneously more brittle. Full article

Lightweighting is a critical focus in the transportation sector, directly enhancing efficiency and significantly reducing costs. In electric vehicle (EV) design, the body surrounding the battery must effectively absorb impact, especially during crashes. This study aims to improve the crash performance of the side profiles in the battery box of an M1 category vehicle. It is based on the crash test in Annex 8D of the ECE R100 regulation. In this study, the safe displacement at which the battery will not deform is set as 20 mm, and the maximum force and energy absorption at this displacement are compared. In total, 33 different electric and hybrid vehicle models were benchmarked in this study. L-shaped geometry and aluminum materials are generally preferred; this study focuses on using glass-fiber-reinforced polymer (GFRP) pultruded profiles to make batteries more durable and lighter. The GF800 material was selected for its superior mechanical strength among glass fiber composites. A virtual tensile test verified its properties. A unique hybrid model combining honeycomb and auxetic geometries was developed, showing a crash performance improvement of ~360% over honeycomb structures and ~88% over auxetic structures. Through multi-objective optimization using artificial neural networks (ANNs), 27 models were analyzed, leading to an optimized design. The final design resulted in the battery box side profile being 23.9% lighter and 38.6% cheaper, and exhibiting a performance 3% higher. This study demonstrates significant advancements in EV safety and cost efficiency, highlighting the practical benefits of innovative material and design approaches. Full article

This study aimed to evaluate which of five commonly used methodologies for agricultural gypsum application in no-tillage systems under tropical agricultural conditions is the most efficient in sandy soils. The evaluation focused on soil chemical and physical properties, nutrient movement through the soil profile, and crop productivity. Methods: Soil layers of 0–0.20 m and 0.20–0.40 m were analyzed. Data were subjected to analysis of variance, and means were compared using Student’s t-test (p < 0.05). Principal component analysis (PCA) and multivariate analysis were also performed. Results: An increase in calcium (Ca), potassium (K), and sulfur (S) contents was observed at the analyzed soil depths, along with a reduction in subsurface aluminum saturation (m%). Gypsum application also increased the dry matter yield of cover crops. Conclusions: For sandy soils under no-tillage systems with high nutrient export, aiming to improve soil fertility and aggregation, the gypsum application methodologies proposed by Caires and Guimarães or Raij and collaborators are recommended. According to multivariate analysis, these methodologies showed the best correlation with base saturation (V%), a key indicator of soil fertility. Additionally, the Caires and Guimarães method demonstrated a stronger correlation with maize productivity. However, none of the evaluated methodologies increased soybean yields. Full article

The primary objective of this study was to compare the nutrition and metabolite profiles of Siraitia grosvenorii from different regions (namely Yongfu and Longsheng) and processing stages. Our findings showed that fresh Siraitia grosvenorii from Longsheng contained higher levels of total sugars, protein, and crude fat compared with those from Yongfu, though both regions had similar dietary fiber and ash content. Dried Yongfu Siraitia grosvenorii showed increased nutrient levels. A mineral analysis revealed that fresh Siraitia grosvenorii from Yongfu had the highest levels of calcium, magnesium, and potassium along with distinct differences in other mineral concentrations compared with Longsheng. Notably, fresh Yongfu fruits had higher mineral content than dried ones, except for aluminum and selenium. Through an untargeted metabolomics analysis, we identified 470 metabolites, showing significant variation between fresh samples from Yongfu and Longsheng and between fresh and dried Yongfu samples. Key metabolites included carboxylic acids, fatty acyls, and organooxygen compounds. Additionally, we observed significant enrichment in metabolic pathways such as phenylpropanoid biosynthesis, galactose metabolism, and linoleic acid metabolism, with notable differences in metabolite regulation depending on the region and processing stage. These findings highlight the influence of regional environmental factors and drying processes on the nutrient and metabolite composition of Siraitia grosvenorii. Full article

The surface topography and chemistry of titanium–aluminum–vanadium (Ti6Al4V) implants play critical roles in the osteoblast differentiation of human bone marrow stromal cells (MSCs) and the creation of an osteogenic microenvironment. To assess the effects of a microscale/nanoscale (MN) topography, this study compared the effects of MN-modified, anodized, and smooth Ti6Al4V surfaces on MSC response, and for the first time, directly contrasted MN-induced osteoblast differentiation with culture on tissue culture polystyrene (TCPS) in osteogenic medium (OM). Surface characterization revealed distinct differences in microroughness, composition, and topography among the Ti6Al4V substrates. MSCs on MN surfaces exhibited enhanced osteoblastic differentiation, evidenced by increased expression of RUNX2, SP7, BGLAP, BMP2, and BMPR1A (fold increases: 3.2, 1.8, 1.4, 1.3, and 1.2). The MN surface also induced a pro-healing inflammasome with upregulation of anti-inflammatory mediators (170–200% increase) and downregulation of pro-inflammatory factors (40–82% reduction). Integrin expression shifted towards osteoblast-associated integrins on MN surfaces. RNA-seq analysis revealed distinct gene expression profiles between MSCs on MN surfaces and those in OM, with only 199 shared genes out of over 1000 differentially expressed genes. Pathway analysis showed that MN surfaces promoted bone formation, maturation, and remodeling through non-canonical Wnt signaling, while OM stimulated endochondral bone development and mineralization via canonical Wnt3a signaling. These findings highlight the importance of Ti6Al4V surface properties in directing MSC differentiation and indicate that MN-modified surfaces act via signaling pathways that differ from OM culture methods, more accurately mimicking peri-implant osteogenesis in vivo. Full article

Friction-stir-welded dissimilar AA2024/AA7075 joints have an apparent influence on grain and texture development at the weld interface due to differences in physical and chemical properties between the two aluminum alloys. In this work, the effect of tool shoulder profile on grain structure and texture evolution in the center interface zone (CIZ) and bottom interface zone (BIZ) of dissimilar AA2024/AA7075 joints were quantitatively studied by electron back-scattering diffraction (EBSD). The results indicate that abundant fine and coarse equiaxial grains are produced in the CIZ and BIZ of the joints produced with a concentric circle shoulder (CCS) and three-helix shoulder (THS), and the average grain size of the BIZ is lower than that of the CIZ for the same CCS or THS joint. A higher degree of recrystallization occurs in the CIZ of the joint with a CCS than that of the joint with a THS, while a similar degree of recrystallization is presented in the BIZ of the two joints. For the distribution of local misorientation angle between the two sides of the interface in the same CCS or THS joint, the CIZ manifests relatively uniform behavior, while the BIZ presents the characteristics of uneven distribution. Tool shoulder profile has a significant impact on the texture components at the weld interface, which results in different types of shear textures generated in the CIZ and BIZ of the two joints. It is beneficial to make out the microstructural evolution mechanism at the weld interface in dissimilar FSW joints for engineering applications in this study. Full article

Gelled fuels are rheologically complex, non-Newtonian fluids. They combine the benefits of both liquid and solid states, reducing risks of leakage, spilling, and sloshing during storage while maintaining the ability to be sprayed inside a combustion chamber. Additionally, suspending energetic particles, such as metal powders of aluminum and boron, can significantly enhance their energy density compared to conventional liquid fuels. In this study, several kerosene-based and ethanol-based formulations were experimentally investigated, using both organic and inorganic gelling agents. The compositions were optimized in terms of the gellant amount and manufacturing process. Some of the most promising gellants for kerosene include fatty acids, such as Thixcin^® R or THIXATROL^® ST, and metallic soaps, such as aluminum stearate and zinc stearate. The effects of various co-solvents were assessed, including ketones (methyl isoamyl ketone, methyl ethyl ketone, and acetone) and alcohols (ethanol and octadecanol). Sugar polymers like hydroxypropyl cellulose were tested as gelling agents for ethanol. A preliminary rheological analysis was conducted to characterize their behavior at rest and under shear stress. Finally, a novel approach was introduced to study the stability of the gels under vibration, which was derived from a realistic mission profile of a ramjet. Finally, the ideal gravimetric specific impulse was evaluated through ideal thermochemical computations. The results showed that promising formulations can be found in both kerosene-based and ethanol-based gels. Such compositions are of interest in practical airbreathing applications as they have demonstrated excellent stability under vibration, ideal combustion properties, and pronounced shear-thinning behavior. Full article

The objective of this research was to evaluate the effect of dye obtained from Buddleja coriacea and metallic mordants on the chromatic properties, textile characteristics, spectral profiles, and color stability in alpaca fibers. The dye extraction technique involved boiling in an aqueous solution, followed by filtration. Subsequently, alpaca yarns were dyed using the resulting extract following a standard protocol. The applied mordants included sodium sulfate (Na₂SO₄), aluminum sulfate and potassium dodecahydrate (KAl(SO₄)₂·12H₂O), and oxalic acid (C₂H₂O₄). Spectroscopy UV-Vis and FTIR spectrophotometry methods were used for the characterization of the dyed samples and analysis of the dye during the dyeing process. The findings revealed the formation of four distinct color tones. Additionally, it was determined that the mordants influenced the chromatic properties of the fibers dyed with Buddleja coriacea extract without modifying their textile characteristics. The identified spectral bands corresponded to keratin, the structural protein of the fibers. Changes in the intensity of these spectral bands were observed in the dyed samples, attributable to the presence of different mordants. Wet rub fastness was found to be inferior to dry rub fastness, which has implications for textile maintenance. In conclusion, Buddleja coriacea flowers provide an effective yellow dye, and when combined with various mordants, they allow for a variety of shades and hues in alpaca fiber yarns. Full article

Aluminum (Al) can cause endocrine disruption in aquatic animals, but assessments of animal social behavior in neotropical teleost fish species with importance for Brazilian aquaculture have still not been addressed so far, which can further complete this ecotoxicological knowledge. In order to evaluate the social behavior and plasma cortisol concentration of fish exposed to Al, we performed a 1 h acute exposure with Astyanax lacustris couples in three different experimental groups: control in neutral pH (CTL/n group), acid pH (pH/ac group), and aluminum in acid pH (Al/ac group; 2.0 mg L⁻¹). An ethogram of social interactions between males and females and swimming activities were performed. Furthermore, the cortisol plasma concentration was measured by enzyme-linked immunosorbent, and the gonadal maturation stage of the animals was evaluated by histology. Adult and mature females in the CTL/n and pH/ac groups were more aggressive and active than mature males, including several attacks on the male. Moreover, males did not present attack behavior in these groups at any time, but did show submission behavior and constant avoidance of female attacks. In the Al/ac, females did not attack males, couple decreased swimming activity, a repetitive movement toward the aquarium surface, and high mucus production were observed, making the water cloudy. Regarding cortisol plasma concentration, males had higher cortisol plasma concentrations than females in the CTL/n and pH/ac groups, which was not observed in the Al/ac group. Therefore, Al in addition to being described in the literature as an endocrine disruptor, it can be considered as behavioral disrupter in A. lacustris in this important freshwater species cultivated in South America. Full article