Investigation of Basalt Woven Fabrics for Military Applications

Basalt rock is a black or gray fine-grained rock in the family of igneous rocks, formed by cooling of molten lava. It is commonly found in the Earth’s crust, is abundant throughout the world, and can be easily mined. Basalt rock possesses certain qualities similar to thermoplastics and metals, i.e., it melts when heated to specific temperatures (1100 to 1300 °C), and can be drawn into flexible fibers, a process similar to the manufacture of S-2 and E-glass fibers.

Posted in: Briefs, Materials, Defense industry, Fabrics, Fibers, Materials properties

Size Scale and Defect Engineered Nanostructures for Optimal Strength and Toughness

Realistic combinations of ceramics and/or semiconductors have been developed that simultaneously achieve high hardness (>40 GPa) and toughness (>400 MPa*m1/2). To achieve this goal, there were three primary objectives: (1) the development of physically based dislocation models to understand the deformation of brittle materials, (2) the synthesis of model ceramic nanocomposites that demonstrate high hardness and toughness, and (3) the detailed understanding of the arrangements and types of dislocation structures in small volumes. This involved the uniaxial compression of Si nanovolumes (spheres and towers) using a combination of TEM in situ indentation and molecular dynamics simulations for objective (1), the deposition of Si-SiC core-shell nanotowers for objective (2), and the HR TEM analysis of deformed Si nanovolumes for objective (3).

Posted in: Briefs, Materials, Ceramics, Composite materials, Nanotechnology, Semiconductors, Durability

High-Temperature Silicon Carbide Power Module for Military Hybrid Electric Vehicles

The ever-increasing electrical power, power density, and cooling requirements of present and future military platforms are pushing silicon-based power electronics systems to their operational limits. To address future needs, wide bandgap semiconductor materials such as silicon carbide (SiC) and gallium nitride (GaN) were developed for electronic applications. Using these semiconductor materials, a new generation of wide bandgap power devices is being developed.

Posted in: Briefs, Materials, Power electronics, Materials properties, Semiconductors, Hybrid electric vehicles, Military vehicles and equipment

Tunable Infrared Material System

The objective of this work was to lay the groundwork for the development of a new tunable II-VI infrared (IR) material system using mature III-V semiconductors as lattice-matched substrates. Mercury cadmium selenide (HgCdSe) was studied as an alternative to mercury cadmium telluride (HgCdTe) as an IRdetecting material.

Posted in: Briefs, Materials, Optics, Nanomaterials, Semiconductors

Nonlinear Acoustic Metamaterials for Sound Attenuation Applications

An acoustic crystal composed of tightly packed spherical particles can exhibit a wide spectrum of acoustic properties with responses varying from linear to highly nonlinear regimes. The physical attractiveness of these crystals resides in the controllability of such acoustic responses by simple manipulation of static pre-compression applied to the material.

Posted in: Briefs, Materials, Materials properties, Acoustics, Noise

Transparent Ceramics for High-Energy Laser Systems

When a high-energy laser (HEL) beam transmits through a window material, a part of the laser energy is absorbed by the material and causes optical aberrations. This absorbed energy results in material heating in the local exposed region, changing its refractive index based on the material’s thermo-optic coefficient, thermal expansion coefficient, and stress optic coefficient. These changes result in beam distortion and loss of output power, measured as optical path distortion (OPD), which has a severe impact on system performance.

Posted in: Briefs, Materials, Windows and windshields, Lasers, Ceramics, Heat resistant materials

Optical Properties of Aligned Carbon Nanotube Mats for Photonic Applications

Carbon nanotubes possess unique electronic properties that are very useful for building electro-optical devices at nanometer scales. In optoelectronic applications, a large number of carbon nanotubes will be assembled in a desired form.

Posted in: Briefs, Materials, Electronic equipment, Optics, Nanomaterials

Ultraviolet Polymerization of Hydrodynamically Shaped Fibers

Materials composed of stacked plates are stronger than the same materials in bulk. However, such stacked plate materials are generally composed of hard, inorganic materials cemented together by a more flexible substance, and do not occur in long fiber shapes. Very few natural or manmade materials are composed of stacks of plate-like fibers. Manmade polymer fibers are nearly always round because they are fabricated using two-phase systems; for example, a solubilized polymer precursor or a monomer–initiator solution is introduced into air by electrospinning, extrusion, or pulling.

Posted in: Briefs, Materials, Fabrication, Fibers, Materials properties, Polymers

Quasicrystalline Aircraft Coating Shows Promise for Cookware, Prosthetics

A technology initially designed to lubricate aircraft parts could lead to more durable nonstick cookware and prosthetic bone-repair implants.

Posted in: Tech Transfer Reports, Coatings & Adhesives

Fundamental Interaction Between Gold Nanoparticles and DNA

Quantum dots (QDs) and nanoparticles (NPs) are made of metal and/or semiconductor materials with diameters ranging from 5 to 100 nm. The properties of these nanomaterials, which depend on their size and the material they are made from, are usually completely different than the properties of their corresponding bulk materials. There may be anywhere from 1 to 1,000 electrons in a single QD, providing numerous possibilities for their opti-

cal and electrical properties.

Posted in: Briefs, Materials, Composite materials, Materials properties, Metals, Nanomaterials, Semiconductors