Preparing Carbon-Coated Current Collectors for High-Power Lithium-Ion Secondary Batteries

Achieving high-power capability of a battery requires minimizing the overall resistance of the electrochemical system. For lithium-ion batteries, much effort has been devoted to minimize the ionic diffusion resistances and electronic resistance associated with the electrode active materials. In the typical electrode configuration, the layer containing the active material is supported on a metallic current collector. The interface between the current collector and active layer imposes additional resistance to charge transfer within the electrode. The advancement in material synthesis technologies has reduced the ionic and electronic resistances associated with the active materials to the point that they become competitive to the other resistance sources. Thus, the significance of the electronic resistance at the active layer/current collector (AL/CC) interface is worthy of re-examination.

Posted in: Briefs, Manufacturing & Prototyping, Lithium-ion batteries, Coatings Colorants and Finishes, Materials properties

Hybrid-electric distributed propulsion explored

A turboelectric distributed propulsion (TeDP) system is a powertrain consisting of a turboshaft engine used solely to provide electrical power through a generator to electric motors driving multiple propulsive fans that are distributed above, below, or inside a wing.

Posted in: Technology Update, Aerospace, Defense, Electric motors, Fans, Turbojet engines, Hybrid electric vehicles

Enabling high-strength composites to reach their full potential

The use of composite materials for construction of aerospace components began in the early 1980s and is now the material of choice for commercial and military airframe designers. Composite material properties such as stiffness, weight, strength, and corrosion resistance have invigorated the transfer of composites within aerospace to include interior components such as seats and service carts. Interior parts and components account for as much as 40% of a commercial airliner’s empty operating weight and represent a larger market (by volume) than airframe structures.

Posted in: Technology Update, Aerospace, Defense, Airframes, Interior molding and trim, Composite materials, Materials properties

Designing quieter aircraft via acoustic simulation

Greater fuel efficiency and low emission requirements have grown into such an urgent imperative in aircraft design that it often overshadows an equally significant factor in air travel—noise.

Posted in: Technology Update, Aerospace, Defense, Simulation Software, Computer simulation, Design processes, Noise

Navigating Regulatory Compliance for UAV Electronics Development

Unmanned Aerial Vehicles (UAV) deliver sophisticated capabilities with tremendous cost advantage over traditional methods. While this technology has evolved from military missions, civil and commercial sectors are beginning to realize many of the same remote sensing benefits. However, one of the main barriers to rapid full-scale commercial growth is the concern for safety. As a myriad of certification agencies scramble to keep up with the unique demands of this fast-growing industry, one thing is clear – where applicable, pertinent certification standards for manned aircraft are starting to apply. For the complex electronics that provide the brains of these systems, this means a swift move towards compliance with DO-178C for software and DO-254 for hardware development.

Posted in: Articles, Aerospace, Defense, Electronic equipment, Regulations, Unmanned aerial vehicles

Simulating Lightweight Vehicles Operating on Discrete Terrain

Engineers increasingly rely on simulation to augment and, in some cases, replace costly and time consuming experimental work. However, current simulation capabilities are sometimes inadequate to capture phenomena of interest.

Posted in: Articles, Aerospace, Defense, Automation, Computer simulation, Lightweighting, Military vehicles and equipment

UUV Developments for Defense and Commercial Applications

Autonomous Undersea Vehicles (AUVs), also commonly referred to as Unmanned Undersea Vehicles (UUVs), have a history dating back to 1957 with the Special Purpose Underwater Research Vehicle (SPURV) developed by the University of Washington's Applied Physics Laboratory. Academia and special government programs drove the early decades of research but advancements were slow. Throughout the 1960s, 1970s, and 1980s, more explosive growth came for the Remotely Operated Undersea Vehicle (ROV) market which had two primary advantages: they were operated via a tether that provided power for the vehicle and man-in-the-loop control.

Posted in: Articles, Aerospace, Defense, Autonomous vehicles, Marine vehicles and equipment, Military vehicles and equipment

The Evolution of Tactical Robots

The lessons of yesterday and today are driving tomorrow’s robotic programs.

A revolution in Unmanned Ground Vehicles (UGVs) is taking place today that focuses on formalizing the permanent integration of ground robots into military organizations within the U.S. Department of Defense and other nations’ military forces as well. Similar activities are likewise cementing the relationship of UGVs to first responder organizations as ground robots continue to prove that they save lives.

Posted in: Articles, Aerospace, Defense, Robotics, Emergency management, Robotics, Military vehicles and equipment

Next-Generation Antenna Design

Materials and Processes Enable New Possibilities for Unmanned Systems Command & Control

Unmanned vehicles are finding increasing usage in military engagements, not only for aerial applications but also for ground and underwater missions. Modern antenna designs can increase unmanned vehicle fuel efficiency through reduced antenna size, increased antenna conformality, and reduced antenna weight. For airborne UAVs, time on station is a critical mission parameter directly influenced by payload weight and aerodynamics. For unmanned ground vehicles, increased antenna conformality reduces the likelihood of accidental damage that occurs with externally protruding antennas.

Posted in: Articles, Aerospace, Defense, Antennas, Aerodynamics, Autonomous vehicles, Unmanned aerial vehicles

Photovoltaic Thermography From the Air

Raleigh, NC

Defective solar cells can destroy an entire module. Therefore, conducting regular inspections using thermography is a great way to perform preventative maintenance on photovoltaics installations. Any noticeable differences in temperature that are encountered can be used to reliably detect electrical, mechanical, installation and processing-related defects, including short circuits, inactive cells, moisture, and poorly soldered joints. As part of scheduled maintenance operations, thermography can provide valuable information for resolving warranty claims.

Posted in: Application Briefs, Aerospace, Defense, Solar energy, Maintenance, Repair and Service Operations, Inspections