The aim of this study was to compare the influence of externally applied "command set" methods (heat, ultrasound) on shear bond strength to enamel of several glass ionomer cements (GIC). The vestibular surfaces of 180 extracted premolars were wet ground until a flat enamel surface was created, and divided into three groups. Three restorative GICs (Fuji IX GP Fast, Fuji Triage, Ionofil Molar AC) were cured in three ways: standard (SC), ultrasonic excitation (UC) and by an external heat source (HC). In each group, teeth were conditioned in two ways: 30 with 10% polyacrylic acid and 30 without conditioning. The GIC were used to fill teflon molds (3 x 4 mm). The samples were loaded in a Universal testing machine (Lrx Material Testing Machine) at a 1 mm/min crosshead speed. Results showed that heat cured Fuji IX on conditioning enamel had significantly greater shear bond strength (13.3 MPa) than all other tested groups (8.6-10.8 MPa) (p < 0.001). The mean shear bond strength in GIC with SC and without enamel conditioning was 3.6-5 MPa and had significantly lower bond strength. Heating of GIC increase bond strength, improves the properties of GIC restoration and can be recommended for use as a "command set" method.
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January 2025
Institute of Materials for Energy and Environment, College of Materials Science and Engineering, Qingdao University, Qingdao, 266071, P. R. China.
Construction of core-shell structured electrocatalysts with a thin noble metal shell is an effective strategy for lowering the usage of the noble metal and improving electrocatalytic properties because of the structure-induced geometric and electronic effects. Here, the synthesis of a novel core-shell structured nanocatalyst consisting of a thin amorphous Pd shell and a crystalline PdCu core and its significantly improved electrocatalytic properties for both formic acid oxidation and oxygen reduction reactions are shown. The electrocatalyst exhibits 4.
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January 2025
Laboratoire d'Energétique et des Transferts Thermique et Massique (LETTM), Faculté des Sciences de Tunis, Université de Tunis El Manar, Campus Universitaire El-Manar, El Manar, Tunis 2092, Tunisia.
The viability of using fibers as reinforcement material for developing lightweight sustainable non-structural construction materials in compliance with the valorization of local by-products has been investigated in this work. This study aims to investigate the effect of the chemical treatment of fibers on the mechanical and hygric properties of bio-sourced clay-sand- fiber composite. This lightweight specimen has been produced from a mixture of 60% natural clay and 40% sand by mass, as a matrix, and reinforced with different amounts of Juncus fibers.
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December 2024
College of Civil Science and Engineering, Yangzhou University, Yangzhou 225100, China.
Polymers (Basel)
January 2025
State Key Laboratory of Chemical Safety, Qingdao 266000, China.
Polyurea (PUR) has been widely used as a protective coating in recent years. In order to complete the understanding of the relationship between PUR microstructure and its energy absorption capabilities, the mechanical and dynamic performance of PURs containing various macrodiol structural units were compared using material characterization techniques and molecular dynamic simulation. The results showed that the PUR polycarbonate diols formed as energy absorbing materials showed high tensile strength, high toughness, and excellent loss factor distribution based on the comparison of stress-strain tensile curves, glass transition temperatures, phase images, and dynamic storage loss modulus.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
College of Biological Engineering, Sichuan University of Science and Engineering, Yibin, Sichuan 644005, China. Electronic address:
Cellulose-based paper is inherently poor in hydrophobicity and mechanical strength, limiting its practical applications in daily life such as packaging materials, water-resistant labels, and disposable tableware. This study aimed to develop an effective and eco-friendly strategy to address these limitations by enhancing the hydrophobicity and mechanical properties of cellulose paper. To achieve this, an internal sizing agent was prepared by combining (3-glycidoxypropyl) trimethoxy (GPS) with natural rosin.
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