Five Approaches to Cooling Military Electronics

Seventy-one degrees C is the temperature of a steak done medium-well. It is also the temperature of an oven used to test thermal characteristics of military electronics. Electronic components in the COTS industry often have temperature limits of 85°C, leaving 14°C of thermal potential to move the heat generated by the components away. Among various cooling approaches, the correct solution for your application depends on meeting your requirements at the lowest possible cost and complexity.

Posted in: Articles, Aerospace, Electronic equipment, Test equipment and instrumentation, Thermal testing, Military vehicles and equipment

Prototyping with Multi-Layer Boards

As electronic components continue to move increasingly into surface- mount packages exclusively, prototype manufacturing firms are seeing a shift in the fabrication and assembly work needed to implement engineering prototypes. The shift is subtle but relentless; as new components come to market in SMT packages, QFPs, BGAs and the like, board design and assembly for prototypes must change to accommodate the surface mount components.

Posted in: Articles, Aerospace, Rapid prototyping, Electronic equipment, Assembling, Fabrication

Gas Turbine Exhaust Recovery Design Improves Propulsion Efficiency

In January, Concepts NREC (CN) was awarded a Phase I Small Business Innovative Research (SBIR) grant from the Navy to improve the power efficiency of its gas turbine prime movers used for ship propulsion. The eight-month analytical study is in collaboration with the Maine Maritime Academy and its principal consultant, Travis Wallace, President, Thermoelectric Power Systems, LLC. The Navy’s RFP required that the power recovery system improve the power output of the prime mover by at least 20%. However, considerations included the effects that transient power demand from the prime mover has on the waste heat flow rate and temperature, which may consequently affect the fatigue integrity of the heat exchangers and stability of the turbomachinery subsystems.

Posted in: Application Briefs, Waste heat utilization, Thermodynamics, Gas turbines, Marine vehicles and equipment

Realistic Simulation Makes Army Helmets Safer

As materials, ergonomic design, and ballistics protection have evolved, the U.S. Army helmet has improved in form and function, from the M1 of WWII, to the 29-layer Kevlar PASGT (Personnel Armor System for Ground Troops), to finally the lighter Kevlar/Twaron ACH (Advanced Combat Helmet) design of today (Figure 1). Helmet liners have progressed too, from compressed paper fibers, plastic, and rayon in the early days to more sophisticated suspension-webbing systems with chin straps constructed from stronger synthetics.

Posted in: Application Briefs, Computer simulation, Finite element analysis, Defense industry, Materials properties, Helmets

Impact of Materials on Microwave Cable Performance

The environments in which microwave cable assemblies are being used today are becoming more challenging with exposure to such conditions as extreme temperatures, chemicals, abrasion, and flexing. Additional challenges include the need for smaller, lighter packaging for cable systems that last longer and cost less. To ensure signal integrity and product reliability, it is essential to identify the electrical, mechanical, environmental, and application-specific constraints that can affect the cable’s overall performance.

Posted in: Application Briefs, RFM Catchall, Electric cables, Materials properties, Polymers

Multifunctional Vehicle Structural Health Monitoring with Piezoelectric Wafer Active Sensors

A novel structural health monitoring (SHM) concept of embedded nondestructive evaluation with piezoelectric wafer active sensors (PWAS) has been developed. PWAS can be structurally embedded as both individual probes and phased arrays. They can be placed inside closed cavities during fabrication/ overhaul (such as wing structures), and then be left in place for the life of the structure. The embedded nondestructive evaluation (NDE) concept opens new horizons for performing insitu damage detection and structural health monitoring of a multitude of thin-wall structures.

Posted in: Briefs, Physical Sciences, On-board diagnostics, Vehicle health management, Product development, Non-destructive tests

Acoustic Detection Using Reverberation

Acoustic detection of undersea objects is difficult due to the uncertain environment and even more difficult when the objects are buried in the seabed. First, sediments generate high backscattering noise due to heterogeneous scatters within the sediments, clouding the object.

Posted in: Briefs, Physical Sciences, Remote sensing, Soils, Acoustics, Noise, Marine vehicles and equipment

Evolutionary Data Mining Approach to Creating Digital Logic

When required to reverse-engineer a product, engineers often do not have design specifications for the system, and the machine may not be disassembled or invasively examined. The engineer might attempt to find the correct signal through trial and error, but this would be very time-consuming, and access to experimental resources is very expensive. To deal with this problem, a genetic program (GP)-based data mining (DM) procedure has been invented.

Posted in: Briefs, Information Technology, Mathematical models, Artificial intelligence, Big data, Systems engineering

Precision Targeting with a Tracking Adaptive Optics Scanning Laser Ophthalmoscope

Adaptive optics (AO) has become increasingly utilized in research ophthalmic diagnostic instruments since their first use nearly ten years ago. Integration of adaptive optics in scanning laser ophthalmoscopy (SLO) is a flying-spot technique whereby scattered light in images is blocked by placement of an aperture at a back conjugate focal plane. Adaptive optics systems sense perturbations in the detected wavefront and apply corrections to an optical element that flattens the wavefront and allows near diffraction-limited focus.

Posted in: Briefs, Medical, Adaptive control, Lasers, Medical equipment and supplies

Trustworthy Hardware for 3D Circuit-Level Integration

Three-dimensional (3D) integration is a promising technology for designing high-performance, low-power systems by stacking multiple integrated circuit dies and connecting them at the circuit level with conductive posts. Most current efforts are at the electromechanical level of getting 3D to work efficiently and cost effectively.

Posted in: Briefs, Electronics & Computers, Connectors and terminals, Integrated circuits, Microelectricmechanical device