Добірка наукової літератури з теми "Specific fibers"

<p>The aim of the present Structural Engineering Document, a state-of-the-art report, is to review the progress made worldwide in the use of fibre rein­forced polymers as structural components in bridges until the end of the year 2000.<p> Due to their advantageous material properties such as high specific strength, a large tolerance for frost and de-icing salts and, furthermore, short installation times with minimum traffic interference, fibre reinforced polymers have matured to become valuable alternative building materials for bridge structures. Today, fibre reinforced polymers are manufactured industrially to semi-finished products and ccimplete structural components, which can be easily and quickly installed or erected on site.<p> Examples of semi-finished products and structural components available are flexible tension elements, profiles stiff in bending and sandwich panels. As tension elements, especially for the purpose of strengthening, strips and sheets are available, as weil as reinforcing bars for concrete reinforcement and prestressing members for internal prestressing or external use. Profiles are available for beams and columns, and sandwich constructions especially for bridge decks. During the manufacture of the structural components fibre-optic sensors for continuous monitoring can be integrated in the materials. Adhesives are being used more and more for joining com­ponents.<p> Fibre reinforced polymers have been used in bridge construction since the mid-1980s, mostly for the strengthening of existing structures, and increas­ingly since the mid-1990s as pilot projects for new structures. In the case of new structures, three basic types of applications can be distinguished: concrete reinforcement, new hybrid structures in combination with traditional construction materials, and all-composite applications, in which the new materials are used exclusively.<p> This Structural Engineering Document also includes application and research recommendations with particular reference to Switzerland.<p> This book is aimed at both students and practising engineers, working in the field of fibre reinforced polymers, bridge design, construction, repair and strengthening.

The study and modelling of EMC are becoming more critical than ever due to the ubiquitous presence of electronic circuits in all aspects of our lives. Specifically, it is crucial to extend these studies to the new frequencies that, in a few years, will be a reality in modern telecommunications systems, such as 5G and its derived technologies. A specific critical field where the proper EMI shielding has been ensured to avoid EMC problems is the electric autonomous vehicles (EAVs). The huge number of electronics systems in new vehicles will dramatically extend the demands on the EMI shielding solutions used to attenuate the radiated emissions that could affect circuits in the vehicle. Metals or metal alloys are the most common EMI shielding materials since they demonstrate adequate shielding capacity against EMI. However, polymers have become up-and-coming materials for EMI shielding with the characteristics of lightweight, flexibility, cost-effective, easy processing, and resistance to corrosion. Consequently, it is necessary to develop EMI shielding materials based on polymers, plastic materials, and fiber composites that ensure compliance with the different standards that regulate 5G and the proper operation of possible systems susceptible to the intentional and unintended signals generated by this new technology. This contribution focuses on characterizing different composite structures performance based on fibers combined with conductive materials in terms of shielding effectiveness, covering the 5G sub-6 GHz frequency range.

Graphite intercalation compounds are a new class of electronic materials that are classified as graphite-based host guest systems. They have specific structural features based on the alternating stacking of graphite and guest intercalate sheets. The electronic structures show two-dimensional metallic properties with a large variety of features including superconductivity. They are also interesting from the point of two-dimensional magnetic systems. This book presents the synthesis, crystal structures, phase transitions, lattice dynamics, electronic structures, electron transport properties, magnetic properties, surface phenomena, and applications of graphite intercalation compounds. The applications covered include batteries, highly conductive graphite fibers, exfoliated graphite and intercalated fullerenes and nanotubes.

Pain is a multidimensional sensory experience that is mediated by complex peripheral and central neuroanatomical pathways and mechanisms. Typically, noxious stimuli activate specific peripheral nerve terminals onto Aδ‎ and C nerve fibers that convey pain and generate signals that are relayed and processed in the spinal cord and then conveyed via the spinothalamic tracts to the contralateral thalamus and from there to the brain. Acute pain is self-limited and resolves with the healing process, but conditions of extensive injury or inflammation sensitize the pain pathways and generate aberrant, augmented responses. Peripheral and central sensitization of neurons (as a result of spatially and temporally excessive inflammation or intense afferent signal traffic) may result in hyperexcitability and chronicity of pain, with spontaneous pain and abnormal evoked responses to stimuli (allodynia, hyperalgesia). Finally, neuropathic pain follows injury or disease to nerves as a result of hyperexcitability augmented by various sensitizing mechanisms.

In the paper discussed in this chapter, Ainsley Iggo used electrophysiology to characterize mechanosensory fibres from the saphenous nerve in cats. Using fine techniques of dissection he recorded from single units and therefore could discriminate between the various types of sensitivity of afferent fibres. This article describes properties of primary afferent neurons in response to precise calibrated mechanical stimuli and focused on mechanical sensitivity of C-fibres. In addition, the manuscript describes the properties of skin-receptor fields. The paper showed that not all C-fibres responded to high-intensity stimuli and that receptive fields were quite small. In addition, it provided a qualitative evaluation of stimuli necessary to activate those fibres. Hence, by isolating fibres that responded only to strong stimulation, this article showed that the peripheral nervous system is equipped with a specific apparatus for detecting nociceptive stimuli; this was a great step forward in understanding the physiology of pain.