Composites have been found to be the most promising and discerning material available in this century. Presently, composites reinforced with fibers of synthetic or natural materials are gaining more importance as demands for lightweight materials with high strength for specific applications are growing in the market. Fiber-reinforced polymer composite offers not only high strength to weight ratio, but also reveals exceptional properties such as high durability; stiffness; damping property; flexural strength; and resistance to corrosion, wear, impact, and fire. These wide ranges of diverse features have led composite materials to find applications in mechanical, construction, aerospace, automobile, biomedical, marine, and many other manufacturing industries. Performance of composite materials predominantly depends on their constituent elements and manufacturing techniques, therefore, functional properties of various fibers available worldwide, their classifications, and the manufacturing techniques used to fabricate the composite materials need to be studied in order to figure out the optimized characteristic of the material for the desired application. An overview of a diverse range of fibers, their properties, functionality, classification, and various fiber composite manufacturing techniques is presented to discover the optimized fiber-reinforced composite material for significant applications. Their exceptional performance in the numerous fields of applications have made fiber-reinforced composite materials a promising alternative over solitary metals or alloys.

/pdf/fiber-reinforced-polymer-composites-manufacturing-properties-f0ipegmttq.pdf

Fiber-Reinforced Polymer Composites: Manufacturing, Properties, and Applications.

Recently published research indicates that natural fibre based polymer composites have limited applications in advanced structural systems due to their low impact performance. However, natural fibres have great potential for reducing the product weight, lowering material cost, and renewability. Hybrid composites made from a combination of natural/synthetic fibres, natural/natural fibres, or synthetic/synthetic fibres are also receiving attention from both researchers and the industry for structural applications owing to the tailored mechanical and impact properties of these materials. The hybridisation process is one of the paramount and more efficient ways to strengthen and improve the performance of composite materials. This review paper examines the impact properties of hybrid composites manufactured with the aim of improving their structural characteristics, and in particular, is focused on the impact resistance and penetration behaviour of hybrid composites reinforced with natural and synthetic fibres as well as their suitability for modern structural applications.

Impact behaviour of hybrid composites for structural applications: a review

Ultrasonic neuromodulation is a rapidly growing field, in which low-intensity ultrasound (US) is delivered to nervous system tissue, resulting in transient modulation of neural activity. This review summarizes the findings in the central and peripheral nervous systems from mechanistic studies in cell culture to cognitive behavioral studies in humans. The mechanisms by which US mechanically interacts with neurons and could affect firing are presented. An in-depth safety assessment of current studies shows that parameters for the human studies fall within the safety envelope for US imaging. Challenges associated with accurately targeting US and monitoring the response are described. In conclusion, the literature supports the use of US as a safe, non-invasive brain stimulation modality with improved spatial localization and depth targeting compared with alternative methods. US neurostimulation has the potential to be used both as a scientific instrument to investigate brain function and as a therapeutic modality to modulate brain activity.

Ultrasound Neuromodulation: A Review of Results, Mechanisms and Safety.

A review on optimization of composite structures Part I: Laminated composites

Fast-scan cyclic voltammetry (FSCV) is used with carbon-fiber microelectrodes for the real-time detection of neurotransmitters on the subsecond time scale. With FSCV, the potential is ramped up from a holding potential to a switching potential and back, usually at a 400 V s−1 scan rate and a frequency of 10 Hz. The plot of current vs. applied potential, the cyclic voltammogram (CV), has a very different shape for FSCV than for traditional cyclic voltammetry collected at scan rates which are 1000-fold slower. Here, we explore the theory of FSCV, with a focus on dopamine detection. First, we examine the shape of the CVs. Background currents, which are 100-fold higher than faradaic currents, are subtracted out. Peak separation is primarily due to slow electron transfer kinetics, while the symmetrical peak shape is due to exhaustive electrolysis of all the adsorbed neurotransmitters. Second, we explain the origins of the dopamine waveform, and the factors that limit the holding potential (oxygen reduction), switching potential (water oxidation), scan rate (electrode instability), and repetition rate (adsorption). Third, we discuss data analysis, from data visualization with color plots, to the automated algorithms like principal components regression that distinguish dopamine from pH changes. Finally, newer applications are discussed, including optimization of waveforms for analyte selectivity, carbon nanomaterial electrodes that trap dopamine, and basal level measurements that facilitate neurotransmitter measurements on a longer time scale. FSCV theory is complex, but understanding it enables better development of new techniques to monitor neurotransmitters in vivo.

Fundamentals of fast-scan cyclic voltammetry for dopamine detection

Design optimization and manufacture of hybrid glass/carbon fiber reinforced composite bumper beam for automobile vehicle

Dopamine (DA) modulates central neuronal activity through both phasic (second to second) and tonic (minutes to hours) terminal release. Conventional fast-scan cyclic voltammetry (FSCV), in combination with carbon fiber microelectrodes, has been used to measure phasic DA release in vivo by adopting a background subtraction procedure to remove background capacitive currents. However, measuring tonic changes in DA concentrations using conventional FSCV has been difficult because background capacitive currents are inherently unstable over long recording periods. To measure tonic changes in DA concentrations over several hours, we applied a novel charge-balancing multiple waveform FSCV (CBM-FSCV), combined with a dual background subtraction technique, to minimize temporal variations in background capacitive currents. Using this method, in vitro, charge variations from a reference time point were nearly zero for 48 h, whereas with conventional background subtraction, charge variations progressively increased. C...

Monitoring In Vivo Changes in Tonic Extracellular Dopamine Level by Charge-Balancing Multiple Waveform Fast-Scan Cyclic Voltammetry.

Effect of the cooling rate on the mechanical properties of glass fiber reinforced thermoplastic composites

Many experiments investigated the neuro modulatory effects of ultrasonic stimulation, yet there are few researches that investigate which parameters are needed to change activity of excitable cells. In this study, changes in neural network activities were recorded during ultrasonic stimulation with various parameters using a multi-electrode array (MEA). This study concludes, ultrasonic stimulation with intensity of 16.14 mW/cm2 induces change to the neuronal network activity. However, the timing of neuronal activity and stimulus was not synchronized. The mechanical stimuli may not have a direct effect on neuronal activities but somehow help neuronal cells to be in a more excitable state, although further study is necessary.

Do Hyoung Kim

Papers

Design optimization and manufacture of hybrid glass/carbon fiber reinforced composite bumper beam for automobile vehicle

Monitoring In Vivo Changes in Tonic Extracellular Dopamine Level by Charge-Balancing Multiple Waveform Fast-Scan Cyclic Voltammetry.

Effect of the cooling rate on the mechanical properties of glass fiber reinforced thermoplastic composites

The effect of focused ultrasonic stimulation on the activity of hippocampal neurons in multi-channel electrode

Investigation of the reduction process of dopamine using paired pulse voltammetry.