Search Results (12)

Over the last three decades, composite structures have become increasingly more common in everyday life, such as in wind turbines as part of the solution to produce clean energy, and their use in the aerospace industry due to their advantages over conventional materials. Most of these advantages are dependent upon the reliability and quality of the manufacturing process to ensure that there are no defects/faults or imperfections during manufacturing. Thus, it is critical to monitor the enclosed environment of moulds during fabrication in real time. This need has caused many researchers—past and present—to create or apply many sensing technologies to achieve real-time monitoring of the manufacturing processes of composite structures to ensure that the structures can meet their requirements. A consequence of these research activities is the myriad of sensing schemes, (for example, optical, electrical, piezo, and nanomaterial schemes and the use of digital twins) available to consider, and the investigations all of them have both strengths and weaknesses for a given application, with no apparent option having a distinct advantage. This review reveals that the best possible sensing solution depends upon a large set of parameters, the geometry of the composite structure, the required specification, and budget limits, to name a few. Furthermore, challenges remain for researchers trying to find solutions, such as a sensing scheme that can directly detect wrinkles/waviness during the laying-up procedure, real-time detection of the resin flow front throughout the mould, and the monitoring of the resin curing spatially, all at a spatial resolution of ~1 cm with the required sensitivity along with the need to obtain the true interpretation of the real-time data. This review offers signposts through the variety of sensing options, with their advantages and failings, to readers from the composite and sensing community to aid in making an informed decision on the possible sensing approaches to help them meet their composite structure’s desired function and tolerances, and the challenges that remain. Full article

An enhanced process for shaping thermoset fiber-reinforced composites using Modified Double-Diaphragm Forming (mDDF) in Prepreg Compression Molding (PCM) is proposed to address limitations in conventional forming quality. To minimize surface defects, prepregs were pre-cut to reduce wrinkle formation and trimmed after preforming. Complex geometries were managed through draping analysis, which enabled identification and mitigation of wrinkle-prone regions. A challenging layup configuration (±45/0/90/0/90/0/±45) was selected, and temperature-dependent behavior of the prepreg—such as resin fluidity and wrinkle characteristics—was evaluated from room temperature to 80 °C. Material characterization included tensile, bias extension, bending, friction, and density tests. Forming simulations using AniForm Suite 3.0 incorporated fitted material parameters for predictive analysis. Experimental validation confirmed that the mDDF process significantly improved fiber alignment and eliminated wrinkle defects, especially in 16 previously identified critical zones. The final parts exhibited superior surface quality and dimensional accuracy compared to conventional PCM, highlighting the potential of mDDF for precision manufacturing of complex thermoset composite structures. Full article

Background/Objectives: Facial analysis is critical for preoperative planning in facial plastic surgery, but traditional methods can be time consuming and subjective. This study investigated the potential of Artificial Intelligence (AI) for objective and efficient facial analysis in plastic surgery, with a specific focus on Multimodal Large Language Models (MLLMs). We evaluated their ability to analyze facial skin quality, volume, symmetry, and adherence to aesthetic standards such as neoclassical facial canons and the golden ratio. Methods: We evaluated four MLLMs—ChatGPT-4o, ChatGPT-4, Gemini 1.5 Pro, and Claude 3.5 Sonnet—using two evaluation forms and 15 diverse facial images generated by a Generative Adversarial Network (GAN). The general analysis form evaluated qualitative skin features (texture, type, thickness, wrinkling, photoaging, and overall symmetry). The facial ratios form assessed quantitative structural proportions, including division into equal fifths, adherence to the rule of thirds, and compatibility with the golden ratio. MLLM assessments were compared with evaluations from a plastic surgeon and manual measurements of facial ratios. Results: The MLLMs showed promise in analyzing qualitative features, but they struggled with precise quantitative measurements of facial ratios. Mean accuracy for general analysis were ChatGPT-4o (0.61 ± 0.49), Gemini 1.5 Pro (0.60 ± 0.49), ChatGPT-4 (0.57 ± 0.50), and Claude 3.5 Sonnet (0.52 ± 0.50). In facial ratio assessments, scores were lower, with Gemini 1.5 Pro achieving the highest mean accuracy (0.39 ± 0.49). Inter-rater reliability, based on Cohen’s Kappa values, ranged from poor to high for qualitative assessments (κ > 0.7 for some questions) but was generally poor (near or below zero) for quantitative assessments. Conclusions: Current general purpose MLLMs are not yet ready to replace manual clinical assessments but may assist in general facial feature analysis. These findings are based on testing models not specifically trained for facial analysis and serve to raise awareness among clinicians regarding the current capabilities and inherent limitations of readily available MLLMs in this specialized domain. This limitation may stem from challenges with spatial reasoning and fine-grained detail extraction, which are inherent limitations of current MLLMs. Future research should focus on enhancing the numerical accuracy and reliability of MLLMs for broader application in plastic surgery, potentially through improved training methods and integration with other AI technologies such as specialized computer vision algorithms for precise landmark detection and measurement. Full article

Due to the adverse effects associated with synthetic cosmetic ingredients, global demand is increasingly shifting toward natural formulations that offer diverse benefits for enhancing skin health and overall beauty. Researchers around the world are extensively exploring a variety of unique natural secondary metabolites for cosmeceutical applications. Among the potential candidates, phlorotannins derived from brown seaweeds have shown significant potential as an active ingredient in cosmeceutical applications. The notable properties associated with phlorotannins include antioxidant, anti-aging, whitening, anti-wrinkling, anti-inflammatory, and hair health and growth-promoting effects, making them valuable in cosmeceutical formulations. However, to date, only a limited number of studies have critically reviewed the cosmeceutical applications of phlorotannins, and most are outdated. Thus, in the present review, primary attention is given to the collected scientific data published after 2020 about the bioactive properties of brown seaweed phlorotannins related to cosmeceutical applications. Full article

Automotive structural components from Advanced High-Strength Steels (AHSS) can be manufactured with Flexible Roll Forming (FRF). The application of FRF in the automotive industry is limited due to flange wrinkling defects that increase with material strength. The new Incremental Shape Rolling process (ISR) has been shown to reduce wrinkling severity compared to FRF and therefore presents a promising alternative for the manufacture of high-strength automotive components. The current work analyzes for the first time the mechanisms that lead to wrinkling reduction in ISR based on the critical stress conditions that develop in the flange. For this, finite element process models are validated with experimental forming trials and used to investigate the material deformation and the forming stresses that occur in FRF and ISR when forming a variable-width automotive component. The results show that in ISR, the undeformed flange height decreases with increasing forming; this increases the critical buckling and wrinkling stresses with each forming pass and prevents the development of wrinkles towards the end of the forming process. In contrast, in FRF, the critical buckling or wrinkling stress is constant, while the longitudinal compressive stress in the flange increases with the number of forming passes and exceeds the critical stress. This leads to the development of severe wrinkles in the flange. Full article

The evaluation of wrinkles in deep-drawn fiber-based materials is crucial for the assessment of product quality and the optimization of manufacturing processes. Wrinkling is a common phenomenon in the deep-drawing process and is caused by tangential compressive stresses on the flanges of the blank. This phenomenon is particularly prevalent for fiber-based materials with high tensile depths and can seriously affect the appearance and mechanical properties of the final product. The objective of this study is to identify the key process parameters affecting wrinkling and to deepen the understanding of their roles and interactions using wrinkle data for deep-drawn paper products. Image analysis techniques are employed, supported by a specially constructed darkroom platform to ensure uniform light intensity for capturing photographs. An automated program is developed for the detection and evaluation of wrinkle characteristics and distribution, which allows the free choice of the region to be detected and the representation of the wrinkle geometry not limited by the number. To enhance the precision of this program, the ellipticity is initially rectified for products without flanges, specifically cup-shaped deep-drawn products. The ellipticity is caused by the pronounced springback effect of the paperboard. The approach is employed to investigate the impact of material properties, blank holder force, drawing depth, drawing clearance, and punch speed on wrinkling formation after the deep-drawing process. The findings reveal that the blank holder force and drawing clearance are critical factors in wrinkle formation, with higher blank holder force generally leading to increased wrinkle numbers. Full article

For decades, Moore’s Law has been approaching its limits, posing a huge challenge for further downsizing to nanometer dimensions. A promising avenue to replace Moore’s Law lies in three-dimensional integrated circuits, where Cu–Cu bonding plays a critical role. However, the atomic diffusion rate is notably low at temperatures below 300 °C, resulting in a distinct weak bonding interface, which leads to reliability issues. In this study, a quenching treatment of the Cu film surface was investigated. During the quenching treatment, strain energy was induced due to the variation in thermal expansion coefficients between the Si substrate and the Cu film, resulting in a wrinkled surface morphology on the Cu film. Grain growth was observed at the Cu–Cu bonding interface following bonding at 300 °C for 2 and 4 h. Remarkably, these procedures effectively eliminated the bonding interface. Full article

The process of tube nosing is a delicate art that involves forming the end of a tubular part without causing any collapse, buckling, or wrinkling. A recent study has delved into the different modes of failure that can occur during this process and has determined the limits of tube nosing through the use of plasticity and thin/thick-walled tube theories. A finite element simulation was developed to replicate the cold-nosing process using conical dies to validate these theories. The results were compared to experimental outcomes for mild steel, hard steel, and annealed aluminium tubes to ensure accuracy. Through this analysis, we identified and confirmed the modes of failure that can restrict the plastic deformation for the tube nosing process. The outcomes were compared to analytical expressions and showed excellent agreement with the experiments, proving that these expressions provide a reliable reference guide for predicting the limits of the tube-nosing process. The FE simulation method also accurately models critical buckling stresses, nosing loads, and failure modes. Full article

Protein phosphatase 2A (PP2A) is a master regulatory protein that plays a critical role in oxidative stress signaling. A novel, proprietary grape seed extract called Activated Grape Seed Extract (AGSE), enriched for PP2A-activating flavonoids, was recently developed and demonstrated to have antioxidant and anti-inflammatory activities. AGSE is a purple-colored powder, with limited solubility restricting its use in a broad range of formulations. Our aim was to develop a formulation that reduced the color and increased the solubility of AGSE, allowing its skin-health-enhancing properties to be utilized in a wider array of products, and to test it clinically. Encapsulation was performed utilizing a liposome and hydroxypropyl-β-cyclodextrin, (HPCD)-based approach to produce Encapsulated AGSE (E-AGSE). Human dermal fibroblasts and epidermal keratinocytes were used to determine expression levels of aging and dermal–epidermal junction (DEJ) markers. EpiDerm™ was UVB-irradiated to measure the effects against cytokine release, DNA damage, apoptosis, and skin barrier. Human melanocytes were used to determine melanin production and mushroom tyrosinase was used for inhibitory activity. A 4-week, 31-subject sensitive-skin clinical was performed with 2% E-AGSE Essence to assess its activity on human skin. We demonstrated that E-AGSE inhibits PP2A demethylation, increases key anti-aging (collagen I, III, elastin) and DEJ markers, protects against UVB-induced DNA damage, reduces inflammation, and promotes filaggrin in vitro. Moreover, E-AGSE reduces melanin production via tyrosinase inhibition. Clinical assessment of E-AGSE showed that it reduces the appearance of wrinkles, brightens the skin, and boosts hydration. E-AGSE is a novel grape seed extract formulation enriched for PP2A-activating flavonoids that is clinically effective in sensitive skin, providing several benefits. Full article

This paper aims to study the wrinkle formation of a prepreg with initial defect during steering in automated fiber placement (AFP). Wrinkle formation has a detrimental effect on the mechanical properties of the final product, limiting the AFP applications. A theoretical model for wrinkle formation has been developed in which a Pasternak foundation and a Koiter imperfection model are adapted to model viscoelastic characteristics of the prepreg tack and initial defect of the prepreg, respectively. The initial defect is defined as a slight deviation of the tow’s mid-plane from a horizontal shape. The initial defect is generated in the tow by moving the tow through the guidance system, pressure of the roller, and resin tackiness. Galerkin method, along with the finite difference method (FDM), are employed to solve the wrinkle problem equation. The proposed method is able to satisfy the different boundary conditions for the wrinkle problem completely. The numerical results show that increasing the initial defect leads to a decrease in critical load and an increase in critical steering radius. To validate the theoretical model, experimental results are presented and compared with model-predicted results. It is shown that the model is well able to capture the trends and values of wrinkle formation wavelengths obtained from the experiment. Full article

A cylindrical deep drawing test was conducted for the purpose of improving the drawability, product accuracy, and quality in warm deep drawing using a superplastic material with large strain rate dependence. Then, the effects of blank holding force (BHF) and punch speed (SPD) on the flange wrinkle behavior and wall thickness distribution were investigated by experiments and theoretical analysis. A Zn-22Al-0.5Cu-0.01Mg alloy superplastic material SPZ2 with a sheet thickness of 1 mm was employed as the experimental material, and a cylindrical deep drawing experiment with the drawing ratio (DR) of 3.1 and 5 was performed at 250 °C. A good agreement was qualitatively obtained between the elementary theory on the flange wrinkle limit, the fracture limit, and the experimental results. In addition, the authors examined each variable BHF and SPD method obtained from the theory and experimentally demonstrated that the variable BHF method has a great effect on uniform wall thickness distribution and that variable SPD has a great effect on shortening the processing time for superplastic materials. Furthermore, the authors demonstrated the effectiveness of the variable BHF/SPD deep drawing method that varies both BHF and SPD simultaneously. Full article

In thin notched sheets under tensile loading, wrinkling appears on the sheet surface, specifically around the cracked area. This is due to local buckling and compression stresses near the crack surfaces. This study aims to numerically study the buckling behavior of a thin sheet with a central crack under tension. A numerical model of a notched sheet under tensile loading is developed using the finite element method, which considers both material and geometrical nonlinearity. To overcome the convergence problem caused by the small thickness-to-length/width ratio and to stimulate the buckling, an imperfection is defined as a small perturbation in the numerical model. Both elastic and elasto-plastic behavior are applied, and the influence of them is studied on the critical buckling stress and the post-buckling behavior of the notched sheet. Numerical results for both elastic and elasto-plastic behavior reflect that very small perturbations need more energy for the activation of buckling mode, and a higher buckling mode is predominant. The influences of different parameters, including Poisson’s ratio, yield limit, crack length-to-sheet-width ratio, and the sheet aspect ratio are also evaluated with a focus on the critical buckling stress and the buckling mode shape. With increase in Poisson’s ratio. First, the critical buckling stress reduces and then remains constant. A higher yield limit results in increases in the critical buckling stress, and no change in the buckling mode shape while adopting various crack length-to-sheet-width ratios, and the sheet aspect ratio changes the buckling mode shape. Full article