Abstract: A pulse-echo technique, based on ultrasonic "long-bar" mode (LBM) velocity measurements, working up to 1700°C is described. Magnetostrictive transducers and ultrasonic lines used in a 40-85 kHz frequency range are detailed. The conditions of choice of fundamental parameters (frequency, line geometry, sample size) are discussed in relation with the nature and the microstructure of ...

This paper deals with the development of a numerical simulation methodology for estimating damages in laminate composite materials caused by a low-speed impact. Experimental tests were performed on laminate plates reinforced with woven carbon fibers and epoxy resin. Three thickness plates were evaluated. The impact loads were transversal and punctual. Two lamina failure criteria were evaluated....

Citrate based polymer poly(octamethylene citrate) (POC) has shown promise when formulated into composite material containing up to 65 wt% hydroxylapatite (HA) for orthopedic applications. Despite significant research into POC, insufficient information about the biocompatibility of the monomers 1,8Octanediol and Citrate used in its synthesis is available. Herein, we investigated the acute cytoto...

Endodontic sealing materials for permanent obturation of root canals are highly variable both in chemistry of setting and in their additives. Conventional materials are based on zinc oxide-eugenol, rosinchloroform, or synthetic resins. These have been extensively tested for biological and technical properties. Most materials are slightly or moderately cytotoxic, and some — notably paraformaldeh...

stances they use in the kitchen and the bathroom are not simple liquids or solids. Everyone is familiar with three states of matter: solids, liquids, and gases. However, creams, shampoo, toothpaste, and ketchup all have properties of both liquids and solids. This paper describes demonstrations and laboratory exercises1 that show intriguing properties of squishy substances, defined as materials ...

introduction: the aim of the present in vitro study was to evaluate the efficacy of d-race, protaper retreatment kit and hand h-files in removal of obturating materials (om) from the curved root canals using cone-beam computed tomography (cbct). materials and methods: sixty extracted molars were prepared and obturated. the samples were divided into three groups ( n =20). in each group the om wa...

The theory of inhomogeneous analytic materials is developed. These are materials where the coefficients entering the equations involve analytic functions. Three types of analytic materials are identified. The first two types involve an integer p. If p takes its maximum value, then we have a complete analytic material. Otherwise, it is incomplete analytic material of rank p. For two-dimensional ...

Materials have central roles in all fields of engineering; they define, through structures and devices, our interfaces to the physical and the virtual world. The emergence of new materials catalyzes transformative advances in civilizations, to an extent that eras of human development are often defined by the prevailing materials used in engineered systems, from the Stone, Bronze, and Iron Ages ...

Life is a specific characteristic of our planet. The diversity of life, biodiversity, is one of the most fascinating phenomena. We know some 1.8 million different species, but all extrapolations show that probably 20 million or more species exist: We know less than 10% of the plants, animals and micro-organisms living on the planet Earth. The editors, who are both biologists, are well acquainte...