Lange Couplers

The construction and port orientation of the Lange Coupler from SemiGen (Londonderry, NH) makes it useful as both a power combiner and splitter for RF and microwave applications. It is a specific type of directional coupler, which allows passive coupling of a defined amount of electromagnetic power. The sweet spot for Lange Couplers has traditionally been UHF to Q-band; the limit becomes frequency. Substrate height and strip width are inversely related to frequency, increasing loss due to the reduced amount of metal available to act as a conductor.

Quality assurance and flight certification of critical aerospace parts and assemblies have reached new levels of sophistication in recent years. Leading aerospace and defense manufacturers worldwide now consider computed tomography (CT) scanning to be an essential part of their non-destructive testing (NDT) toolkit. Far more powerful than the CT used to scan the human body, industrial CT can penetrate almost every material, from superalloys to lead, revealing hidden details that previously could only be found by cutting and destroying finished parts.

Pentek, Inc. designs embedded computer boards and recording systems for DSP, software radio and data acquisition for both COTS and rugged environments. In an interview with Aerospace & Defense Technology, Vice President Rodger Hosking explained how signal recorder technology is being implemented in military unmanned vehicles.

Drones (i.e. quadrotors) are a popular and increasingly widespread product used by consumers as well as in a diversity of industrial, military and other applications. Historically under the control of human operators on the ground, they’re becoming increasingly autonomous as the cameras built into them find use not only for capturing footage of the world around them but also in understanding and responding to their surroundings. Combining imaging with other sensing modalities can further bolster the robustness of this autonomy.

There are many challenges in developing complete performance ontologies and test methodologies to define and evaluate the performance of autonomous systems. Chief among them is the dynamic environment in which the autonomous system is expected to operate. Change in the autonomous system’s environment is expected to affect system performance. Test methodologies have to include all aspects of this dynamic environment.

As the demand for greater control and functionality increases, position-sensor-instrumented hydraulic cylinders are becoming more important in the heavy industry, mobile equipment, and subsea worlds. Position sensors for feedback in hydraulic or pneumatic cylinders have typically used one of three technologies: Linear Variable Inductance Transducers (LVITs), variable resistance potentiometers (Pots), or magnetostrictive transducers (MLDTs). While other sensor technologies have occasionally been used in these applications, the focus of this article is a comparison among these three popular technologies. Ultimately, a user or systems integrator must determine the exact requirements of the application and which technology best satisfies them on a total installed cost versus performance basis. The strengths and weaknesses of linear variable inductance, variable resistance pots, and magnetostrictive sensors are all examined below, together with a feature-by-feature comparison chart.

The U.S. Army Corps of Engineers (USACE) Portland Districts (NWP) maintains safe and navigable waterways in Oregon through a variety of dredging projects, including channel deepening, and dredging sandbars. Placement of dredged sediment occurs at preselected, specific geographic areas categorized as nearshore beneficial use sites. Beneficial use sites are commonly monitored before, during, and after disposal, to evaluate dredge management practices and to avoid potentially adverse effects to the marine environment.

The U.S. Navy is interested in strategies that divers could employ to protect them from loud underwater sounds. Sonar transmissions and other forms of underwater sound, such as that produced by noisy underwater tools, are an occupational hazard for U.S. Navy divers.

Ultra-Low Temperature Elastomer

Greene Tweed’s (Kulpsville, PA) Fusion™ FKM 665, a new generation, ultra-low-temperature and chemical-resistant elastomer, was specifically formulated to meet and exceed the requirements of Aerospace Material Specification (AMS) 7379 and AMS-P-83461. With a temperature range of -70°F to 450°F (-57°C to 232°C), Fusion™ 665 achieves outstanding low-temperature performance without compromising high-temperature performance.

Finding ways to overcome physical limitations so that humans can dive deeper and stay underwater longer has been an ongoing quest. Back in the 15th century, Leonardo Da Vinci drew sketches of a submarine and a robot. Had he thought to combine the two concepts, he would have created a prototype of an unmanned underwater vehicle, or underwater drone. Instead, the world had to wait another five hundred years.