Efficient Use of Carbon Fibers as Heating Elements for Curing of Epoxy Matrix Composites

The aim of this study is to achieve a fully cured thermoset matrix that is heated by a direct electric current passing through the reinforcement fibers i.e., the Joule heating effect. Two types of fibers were used as heating elements for curing the epoxy resins. Kanthal resistance fibers were used as reference heating elements and subsequently, they were replaced by a Torayca Carbon Tow of the same radius. The specimens were cured by the heat produced by a direct electric current passing through the fibers and achieving temperatures of 50 °C and 70 °C. Specimens cured in a conventional oven were also manufactured, to compare the resistance heating method to the conventional one. Next, all specimens were mechanically characterized in a quasi-static three-point bending mode of loading and experimental results were compared to derive useful conclusions concerning the applicability of the technique to polymer/composite materials mass production. Finally, a preliminary economical study concerning power consumption needed for the application of both the traditional oven curing and the carbon fibers heating elements use for the manufacturing of the same amounts of materials is presented, showing a maximum financial benefit that can be achieved, on the order of 68%.

Electrical injury and burns and their management

Though responsible for just 4% of burn centre admissions, electrical injuries present in a myriad of ways. From small, innocuous, partial-thickness injuries on the fingertip, to a high-voltage injury requiring amputation and complex reconstruction, the burn surgeon must be equipped with the knowledge and skill to deal with such varying injuries. This chapter describes the epidemiology of electrical injury and the pathophysiology of electrical current passing through the patient. The management of high- and low-voltage wounds is described, as is the treatment of the systemic effects of the electrical injury.

Modeling and thermal analysis of micro beam using COMSOL multiphysics

In this study, the design and analysis of the micro beam is carried out using COMSOL multiphysics. The current passing through the beam distributes the heat energy due to its resistance that pushes the entire micro beam to the desired distance through thermal expansion. This expansion varies depending on the amount of current passing through the beam and the emitted temperature. The purpose of the model created is to estimate the amount of current and temperature increase required to cause displacement in the proposed micro beam using analysis software. In addition, displacements and temperature data produced in micro beams for different metallic materials (Al, Cu, Ni, and Pt) and different input potentials (0.3 V, 0.6 V, and 0.9 V) are reported. These materials are used as functional materials in the field of micro-electro-mechanical-system because of their important physical and electrical properties. As a result of the simulation studies, increasing the voltage increased the displacement in the materials and the resulting temperature. While there is a serious difference between the displacement data of the materials, the temperatures are close to each other. When 0.9 V voltage is applied, the highest displacement values for Al, Cu, Ni, and Pt are; 7.88 ?m, 5.36 ?m, 3.62 ?m, and 2.72 ?m, respectively. As a result, it has been observed that aluminum used in micro beam design gives a significant amount of dis?placement for the proposed geometry when compared to other metallic beams.

Electrical Characteristics of Underwater Human Body Model in Charging Power Facility

In this study, the electrical simulation of electric shock accidents at a voltage of 220 V was investigated using Andrew s body model in water. The constructed circuit consisted of Andrew s body model. The voltages measured on a hand, breast, waist, were compared with the electric currents measured on the hand, breast, and waist considering the safety limit of an electric current passing through the body. From the results, it can be understood that the magnitude and wave of electric current passing through the body affect the heart s control of a signal, which directly affects the ventricle of the heart in detail. It comes from the simulation through the ATP -Draw program. This study could be useful in solving safety issues for the electric angle limit by measuring flooding body resistance, as well as the voltage and current passing through each part.

Displacement Analysis of the MEMS Device

In this study, the displacement analysis of the microelectromechanical system (MEMS) device was performed. The current passing through the microdevice radiates heat energy as it pushes the device to the desired distance through thermal expansion. The amount of expansion varies depending on the current flowing through the device. With the designed model, the amount of current required for the displacement of the MEMS device is determined. In addition, the displacements produced in the microdevice for different metallic materials (silver and gold) and input potentials (0.4 V, 0.8 V, and 1.2 V) were calculated. These types of materials are frequently preferred in MEMS technology due to their high conductivity. Increasing the voltage value as a result of the analysis studies increased the displacement of the materials. When 1.2 V voltage is applied, the highest displacement values for silver and gold are; 6.45 μm, 4.32 μm, respectively. According to the results, the silver material showed a significant displacement compared to gold material.

Semiconductor whiskers for humidity sensors

In present paper p-type GaPAs whiskers doped with Cu were obtained by VLS method in close bromine system. The whiskers have various morphologies and geometries: imperfect needle-like crystals, ribbons, perfect needle-like crystals and thin plates. The whiskers of various morphologies serve as thermoresistores with TCR of about 1-2 %. The whisker I-U characteristics were investigated dependent on their geometry and external conditions (humidity). Voltage arising on the thermoresisor for two polarities of current passing through it was shown to be dependent on air humidity. Miniature semiconductor sensors of humidity based on GaPAs whiskers have been designed. Physical principles of operation, the perculiarities of design, and main performances of the microsensors were discussed. The whiskers of small diameter (d=50 μm) were shown to measure humidity in the range j=35...97% with sensitivity to humidity g =DU/Uj »2.5×10-3. The miniature dimensions of the whiskers provides very rapid response (of about a few sec) and small time of recovery (less than 30 sec).

Enhancing CO2 methanation over a metal foam structured catalyst by electric internal heating

We develop an electric internal heating method based on a Ni-foam structured catalyst for CO2 methanation, in which the Joule heat generated by electric current passing through the catalyst drives the reaction.

Force Spectroscopy with Quantitative On-Cantilever Force Control

In this work we propose a method for on-cantilever force control for application in force distance (F-z) spectroscopy for intermolecular interaction sensing. In this method we perform the F-z measurements with cantilevers integrating functionalized spheres attached to them. The F-z curve is obtained by controlling the Lorentz force acting at the cantilever free end. The intermolecular interaction forces are measured by measuring the force necessary to retract the cantilever from the surface. The required force is generated by the current passing through the cantilever. In this scenario we monitor the bending of cantilevers using optical beam deflection (OBD) method. Moreover, as deflection of the cantilever was electromagnetically controlled it was possible to calibrate the OBD response as well.