Explore the vast range of titles available.

Delamination in laminated composites originates from premature matrix cracking within the interlaminar region, ultimately leading to ply separation under indirect loading. Among the techniques proposed to mitigate this failure mode, through-thickness stitching has emerged as a localized reinforcement strategy capable of enhancing interlaminar performance without modifying the in-plane laminate architecture. However, previous studies report that stitching can either improve or degrade the mechanical properties of the composite, with stitch density identified as a critical variable. This work aims to keep the tensile strength of a stitched composite at levels comparable to its unstitched counterpart. The reinforcement was applied using an eight-strand polyethylene thread (0.28 mm in diameter) embedded in a low-viscosity epoxy infusion system (MAX 1618 A/B) combined with a 90° biaxial fiberglass woven fabric. The tensile behavior of laminates was examined for three longitudinal stitching configurations consisting of 2, 3, and 5 continuous stitch lines. Results show that increasing stitch count produces a progressive reduction in tensile strength, attributed to stress concentration around stitch sites and microstructural effects such as resin-rich zones and fiber waviness.

Charles A. Beard's trajectory as a political scientist and expert on municipal government has not yet been fully examined. Based on a close analysis of his teaching at Columbia University and his contributions to city government in New York and Tokyo, this article outlines the development of Beard's vision of American democracy. It argues that, unlike most progressives, Beard refrained from endorsing direct democracy measures as a blueprint for reform, focusing instead on streamlining the American system of government to incorporate, in a transparent fashion, both political parties and interest groups. This article showcases Beard's conception of politics and explains how pluralism and functionalism underpinned his proposals for efficient government.

The impact of liquid jets on solid surfaces is a critical hydrodynamic mechanism in applications like cooling and cleaning. Surface properties, particularly superhydrophobicity, can significantly alter flow development throughout the impingement process. This work uses particle image velocimetry (PIV) to investigate a submerged water jet impinging on smooth and superhydrophobic surfaces. The jet, with a 4 mm diameter (D), was operated at a Reynolds number of 4500 and a nozzle-to-surface distance of 10D. Results demonstrate that the superhydrophobic surface (SHS) modifies the flow behavior significantly. Compared to the smooth surface, the peak jet velocity on the SHS increased by 26% in the axial direction and 19% in the radial direction. Furthermore, turbulent kinetic energy (TKE) at the impingement point was substantially higher on the coated surface. These findings are attributed to reduced wall friction on the superhydrophobic surface, which enhances momentum retention and alters turbulent production.

Delamination is a major failure Mode in laminated composites, typically triggered by premature interlaminar matrix cracking and leading to severe structural degradation. To address this, various through-thickness reinforcement strategies have been explored, including three-dimensional woven architecture. Although these designs significantly improve delamination resistance, their industrial adoption stays limited due to reproducibility challenges and the high cost and operational complexity of advanced manufacturing systems needed for controlled through-thickness reinforcement. This study investigates an alternative interlaminar reinforcement method, through-thickness stitching, aimed at enhancing Mode-I delamination resistance of a commercial fiberglass laminate without changing its native architecture. Composites were manufactured using a low-viscosity epoxy infusion system (MAX 1618 A/B) and a [0/90] biaxial fiberglass fabric. An eight-filament polyethylene thread (Ø = 0.12 mm) was introduced in predefined stitch architectures consisting of three longitudinal patterns having two, three, and five continuous stitch lines, referred to as AV, BV and CV samples, respectively. Results show that stitching highly increases Mode-I interlaminar fracture toughness GIC by 0.3808, 0.4152 and 0.5192 kJ/m2 for AV, BV and CV respectively, compared to 0.0265 kJ/m2 for the unstitched composite O, highlighting the strong influence of stitch orientation and spacing on interlaminar performance. But scanning electron microscopy revealed added failure mechanisms in stitched specimens, including localized fiber misalignment of up to 33° and resin-rich regions approximately 0.6 mm in length, suggesting that while stitching enhances delamination resistance, it may also influence other mechanical properties.

Nowadays, different industries, such as the aerospace and biomedical industries, prefer using Ti alloys due to their excellent anti-corrosion properties and ability to generate a TiO2 oxide layer; this induces the use of anodization to increase the useful life of components. The aim of this work is to characterize the electrochemical effect of anodizing treatment on titanium alloys (Ti CP2, Ti-6Al-2Sn-4Zr-2Mo, Ti-6Al-4V, and Ti Beta-C) in NaOH and KOH at 1 M, applying a current density of 0.0025 A/cm2. The electrochemical techniques employed were electrochemical noise (EN) and electrochemical impedance spectroscopy (EIS), supported by ASTM G199 and ASTM G106 in electrolytes of NaCl and H2SO4 at 3.5 wt. % as a simulation of marine and industrial atmospheres. Also, the anodized transversal section and surface morphology were characterized by a scanning electron microscope (SEM). The results of both electrochemical techniques indicated that Ti-6Al-2Sn-4Zr-2Mo anodized in NaOH presented the best properties against corrosion, and the thickness of the oxide was the biggest.

The aim of this paper is to analyze and highlight the structure and functioning of shadow banks as institutions that played a key role in the 2008 financial crisis, which may contribute to identify financial risks in the future. The interrelated growth of shadow banks through their balance sheets is the process that is identified as a mechanism of financial feedback that is transformed into financial fragility and endogenous Minsky-type finance. Shadow banks are the channel of transmission of international financial fragility and not the securitization and the instruments that emerged from this process (CDO, synthetic CDO and CDS) as has been argued. Shadow banks trade and create market for these instruments at the international level, so that the origin and prevention of the international financial crisis can take a broader and better explanation.

La economía global ha registrado un crecimiento extraordinario de la actividad financiera, penetrando los más diversos ámbitos de la vida cotidiana y la producción, en lo que muchos autores identifican como régimen de financiarización; la dimensión nacional del fenómeno como la financiarización corporativa, de la vivienda y de recursos naturales, entre otros, son dimensiones que han captado la atención de académicos. A partir de 2016 la economía argentina ha transitado por una serie de políticas tendientes a incrementar la financiarización. Tenía entre sus objetivos la expansión de crédito y la construcción de un mercado de titularización, especialmente el hipotecario, con el fin de apuntalar la debilitada actividad económica y dar una respuesta al problema social de la vivienda.

Stitched filaments are known to modify the mechanical properties of glass-fiber-reinforced polymers 2D (GFRPs 2D), so studying the effect on mechanical properties is underway to determine the critical variables involved. This research focuses on the study of the tensile strength effect of stitched low-density Barkley FBA BGQS15-15 nylon monofilament on biaxial E-Glass Saertex 830 g/m2 (+/−45°) cured with Polyester Sypol Resin 8086 CCP using a vacuum infusion process. Four specimens were made with longitudinal distances between the stitched reinforcements of 0.5, 1.0, 1.5, and 2.0 cm, respectively. Tensile strength tests based on standard ASTM D3039 were performed to study how stitching can affect toughness, Young’s modulus, deformation, ultimate strength, and yield strength. The results indicated that the stitching increases Young’s modulus up to 99.2%, UTS is increased by up to +3.14%, deformation decreases by up to −41.66%, and toughness decreases by up to −36.89%. Although the stitching’s main function is to increase interlaminar resistance, it also induces the formation of stress concentrations by the new threads, and premature failure in the matrix was shown.

Since the 1990s, sanctions have become a potent tool to advance or enforce American imperialism. In that decade, the utilization of sanctions by the United States radically increased as did its use of military intervention. By situating this decade within the broader historical framework of imperialism, this thesis argues that the rise of sanctions must be viewed by their ability and proximity to advance the economic and geopolitical interests of the United States. Spanning into the 21st century, sanctions have retained their centrality to the United States because of its dominant role in the global financial system. To elucidate the corrosive nature of US sanctions, this thesis will offer a historically grounded overview of why the use of sanctions suddenly increased in the 1990s, a broad description of how sanctions serve the interests of American capital and will also focus on two recent recipients of comprehensive sanctions: Iran and Venezuela.