Structural Components Research Articles

Soluplus-Stabilized Nimodipine-Entrapped Spanlastic Formulations Prepared with Edge Activator (Tween20): Comparative Physicochemical Evaluation.

Nimodipine (ND) is a vasodilator drug that is used for acute subarachnoid hemorrhage. It has a predominant hydrophobic property, causing low solubility and low bioavailability. Spanlastics are elastic nanovesicular systems based on non-ionic surfactants and edge activators as major components. The goal of this work is to formulate ND as spanlastic nanovesicles to improve the drug's bioavailability. Spanlastic formulations containing ND were prepared by using the ethanol injection method. The composition of the ND formulation includes Span60 as a nonionic surfactant and Tween 20 as edge activators in different ratios. Stabilizers like Soluplus are used in some formulations and then compared with other formulations without that stabilizer. The evaluation study involved Vesicle Size (VS), PolyDispersity Index (PDI), and Entrapment Efficiency (%EE). Then, the optimized formula was subjected to an in vitro release study and zeta potential, additionally comparing the optimized formula with the formula without soluplus in the same concentration in Scanning Electron Microscopy (SEM), solubility study, Deformability Index (DI), and stability study. The results indicated a significant shift in some evaluation criteria and a non-significant change in other characterizations, including the difference in polymer ratio, sonication time, and the existence of a stabilizer. The best formula, F27, was found to have VS, PDI, %EE, and zeta potential of 125.7±0.29 nm, 0.4744±0.002, and 85.43±0.17% and -20.01 ± 0.89 mV, respectively. The photomicrographs of the prepared spanlastic revealed a more uniform and spherical spanlastic, indicating a greater capacity for continuous release. With the addition of Soluplus, the formula became more stable in one month and had a higher deformability index. A significant shift was observed in both VS and PDI. As the stabilizer concentration increases, VS and PDI will decrease. The non-significant shift was noted in the %EE with the presence of a stabilizer. Soluplus has the ability to spontaneously self-assemble into spherical particles. Additionally, PEG 6000, as a component of Soluplus's structure, has a tendency to form strong or tightly bound bilayers and prevent aggregation and formulation of large vesicles. This study explains the accessibility of the formulation of ND as spanlastic nanovesicles by using the ethanol injection method. This spanlastic formulation contains non-ionic surfactants and edge activators (Span 40 and Tween 20) in varying ratios. To get a stable formula, Soluplus is added to prevent the development of crystals and agglomeration.

Effect of pretreatment and peracetic acid pulping on cellulosic materials converted from spent coffee grounds.

Spent coffee grounds (SCG) are the waste byproducts of coffee brewing. While SCG can be valorized to produce functional biopolymers due to their valuable structural components, the lignocellulosic structure of SCG is resistant to degradation because of the tightly bound lignin. Therefore, a pretreatment step is required before pulping with peracetic acid (PAA), an eco-friendlier alternative to traditional pulping methods, to facilitate the extraction of these desired cellulosic materials. Formic acid:acetic acid:deionized water (FA:AA:W=30:50:20) or 60% (v/v) ethanol pretreatments were applied to SCG to compare the characteristics of the resulting cellulosic materials after PAA pulping. Lignocellulose analysis showed that the lignin content (7.06%) of ethanol pretreated SCG was significantly lower (p<0.05), and the cellulose content (29.52%) was significantly higher (p<0.05) than the untreated SCG (15.50% and 11.50%, respectively), indicating that an adequate amount of lignin was removed to obtain the cellulosic materials after the pretreatment process. Morphological and structural changes in the lignin and hemicellulose were observed in all the pretreated SCG, which further confirmed that these components were degraded with pretreatments and pulping. Ethanol pretreated SCG showed the most optimal results based on the greatest lignin decrease seen from its lignocellulose composition, appearance, and structure. This study exemplified a conversion process to extract cellulosic materials from SCG more efficiently to utilize for cellulose-based products and verify its potential to be valorized as a waste byproduct. PRACTICAL APPLICATION: Coffee companies can provide the spent coffee grounds (SCG) they produce to develop cellulose-based materials to make biodegradable packaging products rather than throwing them out or burning them. Using SCG for producing cellulose-based materials can help promote sustainability and reduce food waste worldwide. SCG can be utilized as an alternative source based on their abundance and desired biopolymeric properties, providing innovative solutions to industries and increasing consumer awareness of this cause.

A novel method: YOLO-CE and 3D point cloud-based feature extraction for welding seams of tower bases

Abstract Robotic automated welding of non-standard steel structures presents significant challenges, particularly for electric power tower bases. This study introduces a novel approach that integrates the You Only Look Once—Compact Invert Block and Efficient Local Attention (YOLO-CE) model, an enhanced version of YOLOV8 for 2D image segmentation, with 3D point cloud technology. The YOLO-CE model is used to accurately extract point cloud data from the target area, which is then processed using the MSAC algorithm for efficient plane segmentation. Weld lines are identified through plane equations, allowing for initial weld point cloud extraction. To further refine accuracy, an optimized evaluation equation is developed that accounts for both the distance between the weld point cloud and the fitted plane, and the angle between their normal vectors. This enables precise classification of the weld point cloud. From this classification, key weld feature points are identified, and their exact positions are determined by calculating the distances between these points and their intersections with three planes. The reliability of the proposed method was validated using a robot for precise measurements, with a total error margin of less than 1.5084 mm, demonstrating high accuracy and stability. Post-operation inspections confirmed that the welds were filled and free from defects, meeting all process requirements. The YOLO-CE model achieved a mIoU of 96.38% and a precision of 99.8%, highlighting its effectiveness. This method provides an efficient and precise solution for the automated welding of non-standard steel structural components and has promising application potential.

Flexural and vibration behaviour of co-cured CFRP composite joints with MWCNT-modified adhesive

Among the diverse adhesive-bonded joining methods, the co-curing technique offers several advantages for fusing structural components. Co-curing technique effectively enhances specific strengths and ensures more equitable stress distribution. This research investigated the multi-walled carbon nanotubes (MWCNTs) incorporated with varying wt.% in carbon fibre-reinforced polymeric (CFRP) composite joints through co-cure bonding techniques. The effects of flexural and vibration behaviour in CFRP composite joints were evaluated using the three-point bending and free vibration tests. Experimental results revealed that the epoxy adhesive containing 0.5 wt.% nanofiller demonstrated the highest flexural strength and modulus. These values were significantly superior to pure epoxy adhesive, exhibiting increases of 270 and 120%, respectively. However, the 1.0 wt.% of nanofiller exhibited the maximum natural frequency under three vibration modes, which is 29, 17, and 14% higher than the pure epoxy adhesive. The statistical analysis of the results was examined using an ANOVA, ensuring the reliability of the findings. Optimisation and prediction were done with the Levenberg-Marquardt artificial neural network, further reinforcing the confidence in the outcomes. The overall coefficient (R) mean square error of 0.99844 is within the acceptable range, indicating that both outcomes are reliable and in agreement.

Weldability and microstructural characterisation of gas tungsten arc welded Al0.3CoCrFeNi high entropy alloy

ABSTRACT High entropy alloys (HEAs) have received significant interest from researchers due to their exciting set of properties such as an optimum combination of strength and ductility. The Al0.3CoCrFeNi alloy has shown promising properties for applications such as structural components in marine environments, cryogenic applications, and antiballistic armour. This study investigates the weldability of Al0.3CoCrFeNi using gas tungsten arc welding (GTAW). GTAW of Al0.3CoCrFeNi results in a higher tensile strength than that of BM. Microstructural investigations were carried out with X- ray diffraction (XRD), scanning electron microscopy (SEM), electron backscattered diffraction (EBSD), accompanied by tensile and hardness testing. The BM and welded samples were found to have yield strengths of 255 MPa and 405 MPa, respectively. However, the welded sample has a lower ductility (20% elongation) than the BM (53% elongation). The high strength and lower ductility of the weld are mainly attributed to the evolution of the BCC/B2 phase and carbide phases in the microstructure of the welded sample. The precipitation of the BCC/B2 phase in the welded sample is a consequence of the lower free energy associated with the B2 phase at intermediate temperatures.

Structure design and ultimate strength envelope of a modular carbon fiber-reinforced polymer (CFRP) laminate tube box on a 5000 ft deep-sea ultra large unmanned underwater vehicle

Deep-sea tube box is a crucial and basic structural component of various deep-sea equipment such as deep-sea submarine and unmanned underwater vehicles. The deep-sea ultra large unmanned underwater vehicle (ULUUV) is the most representative one of them. Tube boxes are the basic modular members on the ULUUV, which are widely used as the load-bearing hull in torpedo launch, load transportation, pipeline protection and etc. Due to the extremely harsh operation condition, deep-sea tube box simultaneously suffers extremely high lateral water pressure and tremendous axial compression induced by water pressure. Considering the strict requirements for lightweight, high strength, and corrosion resistance of deep-sea tube boxes, carbon fiber-reinforced polymers (CFRP) have become the most potential choice for the construction materials of future deep-sea tube box. Thus, the aim of this paper is to make a structure design of a deep-sea CFRP tube box which can operate at the water depth of 5000 ft. In this paper, a detailed design process of the deep-sea CFRP tube box was introduced, including geometrical configuration, critical buckling load prediction method, FE modeling technique and experimental validation. Corresponding to 5 ply schemes, 495 cases of FE analyses were performed to obtain the ultimate strength envelopes of the CFRP tube box subjected to combined axial compression and external lateral water pressure. Based on the obtained results, the best ply scheme for the deep-sea CFRP tube box was figured out. This paper could provide design method and data references for deep-sea CFRP structures which are subjected to combined loads.

Perturbation of Enzyme Structure by nano-Metal Organic Frameworks: A Question Mark on their Safety-by-Design?

Our study investigates the interactions between nanoscale Metal-Organic Frameworks (nMOFs), specifically ZIF-8 and CuIm, and key enzymes: Acetylcholine Esterase (AChE), α-amylase. Using circular dichroism (CD) spectroscopy, we observed significant alterations in the secondary structures of these enzymes upon interaction with nMOFs. AChE showed a reduction in α-helix content from 20.1% to a significantly lower value when exposed to 160µg/mL of nMOFs, with a corresponding increase in β-sheet and other structural components. Enzymatic activity assays revealed that CuIm nMOFs decreased AChE activity by 67.08% at the highest concentration tested (160µg/mL). ZIF-8 also affected AChE activity significantly at this concentration. Similarly, α-amylase exhibited structural changes, with increasing concentrations of nMOFs leading to a near-total loss of secondary structure at 80 and 160µg/mL. These structural changes were accompanied by a marked decrease in enzymatic activity, particularly with CuIm nMOFs showing the most substantial inhibitory effects. Our findings highlight the profound impact of nMOFs on enzyme structure and function, emphasising the need for comprehensive assessments of nMOFs' potential toxicity and understanding the aspects of their safety-by-design.

Bacterial flotillins as destabilizers of phospholipid membranes

From archaea to mammals evolutionary conserved flotillins are scaffolding proteins, recognized for their nandomain-segregating activity. Flotillins form basket-like oligomeric architectures on the membrane, based on a conserved secondary structure composition of the monomeric subunits: a membrane-targeting region, an SPFH domain and a coiled-coil “flotillin” domain. In B. subtilis, the two flotillins FloT and FloA are present, localizing mainly in distinct nanodomains and executing multiple cellular functions. We here use deuterium and phosphorus solid-state NMR to monitor the effect of the different flotillins FloT and FloA and their structural components on model membranes. We find a clear disordering effect of FloT and FloA on the membranes reaching the carbon positions in the centre of the membrane. This effect is imposed by the hydrophobic region and the adjacent SPFH domain and, surprisingly, further supported by the membrane-distant flotillin domain. Biological implications of this disordering action are discussed.

Semiclassical transport in two-dimensional Dirac materials with spatially variable tilt

We use Boltzmann theory to study the semi-classical dynamics of electrons in a two-dimensional (2D) tilted Dirac material in which the tilt varies in space. The spatial variation of the tilt parameter induces a non-trivial spacetime geometry on the background of which the electrons roam about. As the first manifestation of graivto-electric phenomena, we find a geometric planar Hall effect according to which a current flows in a direction transverse to the chemical potential gradient and is proportional to gxy component of the emergent spacetime structure. The longitudinal conductivity contains information about the gravitational red-shift factors. Furthermore, in the absence of externally applied electric field there can be “free-fall” or zero-bias currents that can be used as detectors of terahertz radiation.

A non‐isolated modified ultra high step‐up quadratic boost converter with classical voltage doubler circuit

AbstractThis paper proposes a modified ultra‐high gain DC–DC boost converter. The proposed converter has improved the performance of the conventional converter by reducing the total number of components (1 Capacitor and 1 Inductor) in the design structure. In addition, the continuous input current and high voltage gain features are retained in the proposed structure. The steady‐state modelling including the operating principles and the stress calculation along with the cost analysis of the components have been illustrated. The comparative performance analysis has been carried out to clarify the competitiveness of the proposed converter against the recent models. The proposed model has been simulated in Matlab/Simulink software and further, a 100 W laboratory prototype has been built to evaluate the performance of the proposed converter. The peak efficiency received was 90.5% while delivering 100 W power from the source. The results from the experiments have aligned well with the outcomes of the simulation and verify the correctness of the proposed converter.

Pr-modified microstructure enhances coercivity in Sm2Co17-type magnets

Optimizing components of the cellular structure is a strategy to enhance the magnetic performance of Sm2Co17-type magnets. In this study, Pr is used to modify the cellular structure in Sm2Co17-type magnets, achieving synergistic optimization of coercivity from 32.12 kOe to 34.71 kOe and remanence from 11.23 kGs to 11.36 kGs. Analyses reveal that the increased remanence is attributed to the enhanced saturation magnetization and better grain alignment in the Pr-5 magnet. The incomplete cellular structures and Cu-lean region near grain boundaries are ameliorated in the Pr-5 magnets. Meanwhile, the Pr-modified and Cu-enriched cellular boundary phase, which has a lower magnetocrystalline anisotropy field, enhances the pinning strength of the domain-wall and contributes to the increase in coercivity. The substitution of Pr for Sm has a lower substitution energy in SmCo5 than in Sm2Co17, leading to the slight enrichment of Pr in the 1:5H phase. However, excessive Pr leads to increased amounts of oxides and deteriorates magnetic properties. This work provides valuable insights into developing high-performance Sm2Co17-type magnets by optimizing the microstructure and microchemical components.

Panel-based assessment of ecosystem condition as a platform for adaptive and knowledge driven management.

Ecosystems are subjected to increasing exposure to multiple anthropogenic drivers. This has led to the development of national and international accounting systems describing the condition of ecosystems, often based on few, highly aggregated indicators. Such accounting systems would benefit from a stronger theoretical and empirical underpinning of ecosystem dynamics. Operational tools for ecosystem management require understanding of natural ecosystem dynamics, consideration of uncertainty at all levels, means for quantifying driver-response relationships behind observed and anticipated future trajectories of change, and an efficient and transparent synthesis to inform knowledge-driven decision processes. There is hence a gap between highly aggregated indicator-based accounting tools and the need for explicit understanding and assessment of the links between multiple drivers and ecosystem condition as a foundation for informed and adaptive ecosystem management. We describe here an approach termed PAEC (Panel-based Assessment of Ecosystem Condition) for combining quantitative and qualitative elements of evidence and uncertainties into an integrated assessment of ecosystem condition at spatial scales relevant to management and monitoring. The PAEC protocol is founded on explicit predictions, termed phenomena, of how components of ecosystem structure and functions are changing as a result of acting drivers. The protocol tests these predictions with observations and combines these tests to assess the change in the condition of the ecosystem as a whole. PAEC includes explicit, quantitative or qualitative, assessments of uncertainty at different levels and integrates these in the final assessment. As proofs-of-concept we summarize the application of the PAEC protocol to a marine and a terrestrial ecosystem in Norway.

Addressing gaps in pain research from an integrated whole person perspective

Abstract While our understanding of pain is rapidly growing, some areas of pain research are lagging behind. This article discusses two current and inter-related gaps in knowledge that are in need of addressing: first, the connections between “brain” and “body” components of pain; and second, the process of endogenous pain resolution. Historical reasons for these research gaps are discussed and solutions are outlined based on an integrative, whole person research approach. These include comprehensive mapping of the mechanosensory and nociceptive innervation of deep tissues; developing objective, non-invasive measurements to quantify the metabolic, structural and mechanical components of the peripheral tissue environment; integrating our understanding of pain pathophysiology, across whole organs and whole body, as well as across bio-psycho-social domains; and understanding the interplay of nervous system and peripheral tissue mechanisms that promote the endogenous resolution of pain and prevent its acute-to-chronic transition. Current NIH-led efforts in these areas are outlined, including several studies within the NIH HEAL (or Help End Addition Long Term) initiative and the National Center for Complementary and Integrative Health's strategic priorities in whole person research.

Label-free classification of atherosclerosis plaque via OCT and ultraviolet autofluorescence spectroscopy

We proposed a label-free method for the identification and classification of atherosclerosis plaques by combining optical coherence tomography (OCT) with ultraviolet autofluorescence spectroscopy (uFLS). By aligning the OCT source and the FLS excitation beams, we were able to illuminate the same spot on plaques fixed to the integrated probe, which underwent rotational scanning. This setup enabled the detection of both OCT images and uFLS spectra of the plaques in a co-localized manner. In our approach, a 1300 nm centered swept laser source was utilized for OCT imaging, while a 355 nm laser source, along with a lensed multimode fiber, served as the fluorescence probe for uFLS. The successful acquisition of OCT-uFLS images provided complementary information regarding the tomographic internal structure and biochemical components within the vessels, allowing for comprehensive identification and classification of atherosclerosis plaques. Furthermore, we achieved quantitative measurements and analysis of fluorescence spectra from three main component channels, corresponding to collagen, elastin, and lipid. This enabled us to differentiate atherosclerosis from normal vessel walls and determine the specific types. With the implementation of this dual-modal OCT-uFLS technique, it is possible to facilitate the label-free classification of various histopathological types of atherosclerosis plaques, which holds the potential for both diagnosis and image-guided ablation therapy applications.

An integrated finite element analysis and virtual reality system for structural and indoor nonstructural components of buildings under seismic excitations

Nonstructural components such as furniture, ceilings, and lighting equipment exhibit varying behaviors during earthquakes influenced by factors such as seismic waves, floor heights, friction coefficients of floors, and the proximity of other objects. These variables can differ in each scenario, rendering it challenging for individuals to understand and implement effective seismic protection measures for these components. Under these circumstances, this study aims to develop an integrated finite element analysis and virtual reality (VR) system to simulate and visualize the behavior of indoor nonstructural components under seismic excitation. The finite element analysis system was developed using an adaptively shifted integration (ASI)–Gauss code, and the VR system was implemented using Unity software. For the analysis, the models of the furniture and ceilings were placed on the 1st, 5th, and 10th floors of a 10-story reinforced concrete building model. The seismic response was analyzed using the 100% 1995 JMA-Kobe seismic wave as the input. The results indicated that the 10th floor experienced the most severe damage, with complete ceiling collapse and furniture overturning. On the 5th floor, the ceiling underwent significant plastic deformation without collapsing, and the furniture moved and swayed but remained upright. On the 1st floor, the furniture also moved and swayed, with one piece toppling over. These findings highlight the variability in damage across different floors. Finally, this damage was realistically visualized using VR goggles, which could serve as a powerful tool to enhance public awareness of disaster prevention and mitigation.

Traveling wave vibration characteristics of rotating FGM conical shell

Abstract Conical shell is common structural component in various rotating machinery. The study of traveling wave vibration performance of conical shell is of great significant for the design of rotating machinery. This paper addresses the traveling wave vibration performance of rotating functionally graded material (FGM) conical shells. Artificial springs, uniformly distributed, are employed to simulate the boundary constraints of rotating FGM conical shell. Accounting for the effects of Coriolis and centrifugal forces caused by rotation, the energy equation of rotating FGM conical shell is calculated, and then the dynamical model of the rotating FGM conical shell under elastic supported constraints is established using the Lagrange equation. The influence of key factors on traveling wave frequency and response characteristics of rotating FGM conical shell are investigated including rotational speed, half-cone angle and material components.

Small punch test size reduction to enable high flux irradiation

Screening and qualification of new nuclear materials with superior irradiation resistance requires expensive irradiation exposure and post-irradiation examination before consideration into industrial nuclear structural components. The development of miniaturized test methods is needed for enhanced cost/time efficient testing, while enabling comparative and robust material property estimation in a timely and high throughput manner. The Small Punch Test (SPT) is drawing much interest, especially since the publication of an European standard. Motivated by this standard, a new SP test sample geometry is proposed in order to reduce the material volume to be tested, hences increasing the number of samples that can be introduced in an irradiation rig is proposed. The modified sample diameter has been reduced from 8 to 5.35 mm. The qualification of this new design is described here together with a detailed description of the SPT setup modification as compared to the reference setup of the EN standard. Finite element analyses and a series of experiments have been conducted using both standard and reduced size SP samples to demonstrate that the modified test gives estimates of the basic mechanical properties with the same magnitude of error and validates the modified sample geometry for usage in irradiated material testing.

Multivariate risk assessment for offshore structures by Gaidai risk evaluation method under an accumulation of fatigue damage, utilizing novel deconvolution scheme

Current study presents a state-of-the-art structural spatiotemporal multimodal risk assessment methodology, that is particularly well-suited for multimodal structural dynamics, either recorded physically or numerically simulated over a representative timelapse. Offshore Jacket-type offshore platform, operating in Bohai Bay waters had been selected for the method’s verification. This investigation had shown that, in the presence of in-situ environmental stressors, it is possible to appropriately estimate dynamic structural system’s failure and damage risks. High dimensionality of engineering dynamic structural systems, alomg with nonlinear nonstationary inter-correlations between critical structural components, often present challenges for contemporary reliability methods, mostly limited to univariate and bivariate systems. Operating Jacket platform, subjected to in situ wave loads, had been chosen for this case study to benchmark advocated risk evaluation methodology. Number of hotspot stresses had been selected to represent multivariate structural system. Advocated multimodal method had been proven to be suitable for robust assessment of operational failure/damage risks, as well as for accurate structural life projection. Novel non-parametric deconvolution extrapolation scheme had been employed, providing enhanced numerical stability. Given increased safety concerns within offshore, naval, marine engineering, advocated multimodal reliability methodology may be utilized for safer and economically more viable structural design.

Mode decomposition to identify oscillation patterns of flexible aeroshell

Flexible aeroshells, featuring deformable membrane surfaces supported by pressurized gas, offer a novel re-entry system for high-altitude deceleration during re-entry. The flexibility of structural components introduces unique challenges in predicting aerodynamic behavior, as deformations can significantly alter the flow field, affecting pressure distribution and potentially causing aerodynamic instabilities. Therefore, coupled analysis is crucial to ensure the performance reliability of inflatable aeroshells. This study investigates the unsteady aerodynamic behavior, considering structural deformation in a two-way partitioned coupled manner in transonic flow. The dominant deformation patterns are identified using dynamic mode decomposition and the greedy compressive sensing algorithm. The findings reveal that the primary deformation pattern combines axial deformation and swing oscillation. The dominant oscillation frequencies remain different from the eigenfrequencies, indicating that the aerodynamic force is the primary driving force of such oscillations. The time evolution of these dominant modes indicates purely oscillatory behavior rather than increasing or decreasing trends. These insights are critical for the design and reliability assessment of inflatable aeroshells in varying aerodynamic environments.

Microstructure and crack propagation behavior of 2195 aluminum lithium alloy with different orientations in the friction stir welding nugget zone

The 2195 aluminum-lithium alloy is widely used in the aerospace field, where using friction stir welding technology can achieve lightweight and reduced wear designs for components. Fatigue failure, as one of the main modes of damage affecting the life and reliability of structural components, is particularly significant. This paper thoroughly explores the differences in microstructure and fatigue crack propagation behavior between the advancing side and retreating side of the friction stir welded joint in different sampling directions, providing a theoretical basis for enhancing the fatigue performance of friction stir welds. Characterization of the microstructure of the samples was performed using Electron Backscatter Diffraction (EBSD) and X-Ray Diffraction (XRD), and the fatigue properties were investigated using fatigue crack propagation rate curves and crack growth rate curves. The results indicate that the longitudinal base material grains tend to a fibrous structure, while the axial base material grains are distributed in a lamellar fashion. Compared to the advancing side of weld nugget zone, the retreating side of weld nugget zone has significantly reduced grain size and texture types. The fatigue performance of the retreating side of the weld nugget zone is superior to that of the advancing side, and the circumferential welds outperform the longitudinal welds in terms of fatigue performance.