Temperature Effect on Drop-Weight Impact of Hybrid Woven Composites

The main idea of composite material is to combine different materials to produce a new material with performance unattainable by the individual constituents. It gives flexibility to the designer to tailor the new material with properties to obtain peak performance for a particular application.

Posted in: Briefs, Materials, Design processes, Composite materials, Materials properties

Synthesis of Long-Chain-Branched (LCB) Polysulfones for Multifunctional Transport Membranes

Increasing numbers of technologies are based on the idea of harnessing charge transport for useful processes such as energy harvesting, actuation, and sensing. Although much progress exists based on perfluorosulfonated platforms, new and more complicated parameters arise as applications require multifunctionality in engineering materials. For instance, in addition to using lightweight, durable, stable, high-conductivity proton-exchange membranes in a fuel cell, it may be desirable to have the energy source bear load and operate as a structural installment. The most prevalent class of materials potentially capable of such a tradeoff is rubbery “salt-in-polymer” electrolytes that employ polymer segmental motion for transport of free ions from co-dissolved salts.

Posted in: Briefs, Materials, Fabrication, Conductivity, Elastomers, Electrolytes

Biodegradable MEMS Based on Cellulose Paper

Electro-Active Paper(EAPap) has been recognized as a new smart material that can be used for sensors, actuators, biomimetic robots, and smart wallpapers. EAPap is made with cellulose paper by coating thin electrodes on both sides of it. This paper can produce a bending or longitudinal strain in the presence of an electric field. Also, it can produce an induced charge under the external stress. This EAPap material has many advantages in terms of large displacement output, low actuation voltage, low power consumption, dryness, flexibility, sensing capability, and biodegradable characteristics.

Posted in: Briefs, Materials, Microelectricmechanical device, Sensors and actuators, Fabrication, Lightweight materials, Materials properties, Smart materials

Functionalized Silk Materials

T he goal of this work was to exploit the novel structural, physical, and biological features of silk proteins towards functionalization of materials systems generated from this family of protein. A new generation of functional silk systems is sought to provide novel materials with precise control of material features. Three main directions were planned: (a) protein chimeras to form organic (silk) – inorganic nanocomposites; (b) formation of electronic materials using a similar design strategy, but based on enzymatic coupling reactions to form conducting polymers; and (c) continuing to understand and exploit novel processing approaches with these proteins towards new functional materials systems.

Posted in: Briefs, Materials, Research and development, Fabrication, Biomaterials, Materials properties

Dynamic Response and Failure Mechanisms of Layered Ceramic-Elastomer-Polymer/Metal Composites

A thorough study through a combination of ballistic and impact experiments, microscopic failure characterization, and numerical simulations has been carried out in order to decipher the underlying mechanisms involved in the interaction between a blast and/or a blast-induced high-velocity projectile and advanced ceramic-polymer and metal-polymer composites, resulting in an improved ballistic efficiency and impact- and blast-resistant structural system.

Posted in: Briefs, Materials, Ceramics, Composite materials, Elastomers, Metals, Protective equipment, Military vehicles and equipment

Ultra-Low-Power Radios for Ad-Hoc Sensing Networks

Anew method has been developed for the design of a miniature, low-power, low-cost radio node capable of self-organization and communication within an ad-hoc network. The integrated radio transceiver, combined with a backend processor in a single networkable node, offers unique network scalability and low power levels that will enable applications that are not possible with any existing sensor node platform. One unique feature of this radio is that the proposed integrated microchip can be mass produced in a CMOS process without a costly external crystal so that the network formed by a set of homogeneous nodes is robust to network changes or node failure. These characteristics enable formation of reliable, inexpensive ad-hoc networks with group intelligence and long lifetimes.

Posted in: Briefs, Electronics & Computers, Communication protocols, Integrated circuits, Radio equipment, Durability

MEMS Resettable Circuit Breaker and Switch for DC-DC Voltage Converters

Resettable circuit breaker cantilevers use silicon dioxide (SiO2) for temper ature compensation. The compressive stress in the SiO2 causes the cantilever to bow upwards 400 μm after release. In the DC-DC voltage converter, the gap between the electrodes is 1.4 μm. After release, the cantilevers are stuck down. A short-loop experiment was conducted to better understand the cantilever behavior by omitting the contact metal and SiO2 layers from test cantilevers.

Posted in: Briefs, Electronics & Computers, Microelectricmechanical device, Switches, Test procedures

Finite-Element Simulations of Field and Current Distributions in Multifilament Superconducting Films

The separation of high-temperature superconducting (HTS) tapes in filaments is a viable approach to reduce AC losses in HTS high-power applications, where AC currents and/or fields may be applied in addition to any DC field present. Methods such as mechanical, laser scribing, photolithography, or direct printing on buffered substrates using inkjet deposition have been used to create the filaments in the second-generation HTS coated conductors in order to reduce hysteretic losses. However, losses of the finely striated tapes can still be noticeably larger than predicted by analytical expressions, due to the addition of coupling currents or lack of field penetration, and such deviation tends to grow with increasing filament density. In order to reduce the magnetic coupling between filaments and the associated AC losses, an in-depth understanding of flux and current dynamics in the multifilamentary HTS, in realistic conditions, is required.

Posted in: Briefs, Electronics & Computers, Finite element analysis, Electromagnetic compatibility, Voltage regulators, Conductivity

Nozzles for Focusing Aerosol Particles

Several nozzles have been designed to aerodynamically focus aerosol particles into a small-diameter jet, so that individual particles can be illuminated by a laser beam and their light scattering and/or laser-induced fluorescence (LIF) spectra can be measured. An additional nozzle can aerodynamically puff selected particles out of the airstream so that they can be sorted and collected.

Posted in: Briefs, Mechanical Components, Nozzles, Test procedures, Aerodynamics

Parallel Hybrid Vehicles Using Fuzzy Logic Control

A fuzzy logic controller for hybrid vehicles with parallel configuration was proposed. Using the state-of-charge (SOC) of the energy storage, the driver command, and the motor/generator speed, a set of rules was developed. The fuzzy logic controller can determine the split between the electric motor and the internal combustion engine to achieve better fuel economy and low emission performance without losing vehicle performance.

Posted in: Briefs, Mechanical Components, Fuzzy logic, Architecture, Hybrid electric vehicles, Vehicle performance