Tech Briefs

Micro-Composite Fabrication via Field-Aided Laminar Composite Processing

Much work has been accomplished since the discovery that particles in a dielectric fluid experience forces when placed in an electric field, including mathematical descriptions of the forces and resulting motion of particles of differing shapes, particle separation and segregation for use in drug delivery, and even the manipulation of long-chain molecules of certain polymers.

Posted in: Briefs, Manufacturing & Prototyping, Fabrication, Composite materials, Polymers

Tin-Based IV-IV Heterostructures Fabricated Using Molecular Beam Epitaxy

The indirect nature of the fundamental energy gap in the elemental semiconductors Si and Ge prevents the use of these materials and their alloys in laser devices. The objective of this work is to fabricate Sn-based IV-IV compounds for finding direct bandgap material. This work focuses on the material system GeSn/Ge, from the growth, characterization, and optical measurement. Experimental evidences on pseudomorphic growth of thick Ge1-xSnx film for Sn composition up to 10% and the direct optical transition are presented.

Posted in: Briefs, Manufacturing & Prototyping, Lasers, Fabrication, Alloys, Semiconductors

Stencil Mask Methodology for Parallelized Production of Microscale Mechanical Test Samples

Over the past decade, there has been considerable progress in the development of new mechanical testing methods to characterize the properties of materials at the micro and nano scales. One common application of these testing methodologies is the measurement of mechanical properties of structures that are physically small in scale, such as the strength of nanowhiskers and MEMS devices. Another common application is the use of small sample testing to gain insight into plastic deformation processes through systematic alteration of the sample dimensions in order to help isolate selected aspects of material behavior. Examples of these studies include the exploration of size-scale strengthening effects, the quantitative measurement and analysis of dislocation avalanches, and the measurement of local property variations in engineering alloys.

Posted in: Briefs, Manufacturing & Prototyping, Materials properties, Nanotechnology, Test procedures

Software Design for CFD Rotary-Wing Aeromechanics Modeling

Helicopter flight involves many multidisciplinary physics problems that are difficult to predict with today’s engineering modeling and simulation tools. Rotor aerodynamic systems involve complex interactions among the rotor blades, rotor wakes, and fuselage, and they create challenges such as simultaneous modeling of rotating and nonrotating components; retreating-blade, low-speed dynamic stall; advancing-blade transonic flow; rotor “trim” requirements to balance aerodynamic and dynamic forces for particular control settings; and strong coupling between rotor-blade aerodynamics and rotor blade dynamics (both rigid and elastic blade motion).

Posted in: Briefs, Software, Computational fluid dynamics, Aerodynamics, Rotary-wing aircraft

Crumple Zone Software Absorbs Attack Effects Before System Failures

A higher level of structural and operational endurance and ruggedness can be achieved in software systems by strategically introducing crumple zones (CZs) in the system architecture. Analogous to the crumple zone in an automobile, a CZ stands before critical components and “absorbs” the effects of attacks by localizing or eliminating the damage they can cause and leaving the critical components intact and unaffected. The concept of software CZs is broadly applicable; this work focuses on CZs for SOA.

Posted in: Briefs, Software, Architecture, Computer software / hardware, Cyber security

General Runtime/Architecture for Many-core Parallel Systems (GRAMPS)

The era of obtaining increased performance via faster single cores and optimized single-thread programs is over. Instead, a major factor in new processors’ performance comes from parallelism: increasing numbers of cores per processor and threads per core. In both research and industry, runtime systems, domain-specific languages, and more generally, parallel programming models, have become the tools to realize this performance and contain this complexity.

Posted in: Briefs, Software, Architecture, Communication protocols, Computer software / hardware

Weapon Center of Mass Calculator

The Weapon Center of Mass (COM) software allows researchers to easily determine mass properties of a weapon system. The tool presents a photograph of the weapon and allows the user to place weight anywhere on the weapon by clicking on the screen. After the weight is placed, the software returns the mass properties of the weapon, including the effects of the added weight. It is based on fundamental equations found in physics and biomechanics, and can determine the effects of as many as four added weights. The added weight can be accoutrements (such as new sights), additional weapons (such as a grenade launcher), or any other object that is mounted to the weapon.

Posted in: Briefs, Software, Computer simulation, Computer software / hardware, Defense industry