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Liquid Cooling Takes Aim at Gamer PC Applications

Recent technical advances in graphics processing units have accelerated the proliferation of high-power graphics processing units (GPUs) and multiple GPUs in high-end gamer PC applications. Characterized by very high heat loads, this application is causing increasing numbers of OEMs to investigate alternative methods, such as liquid cooling, to achieve the level of thermal management needed for dramatically higher system-power levels. Traditional GPU cooling strategies, such as those combining a heat pipe, heat sink, and fan, provide diminishing thermal performance at 120W per chip. Alternatively, the aggressive cooling requirements of gamer PCs and other high heat-flux processor applications are proving to be fertile ground for “non-traditional” approaches that offer at least 25% better thermal performance, as typified by advanced liquid-cooling systems (LCS) (see figure 1).

Posted in: Articles, Articles, Electronics & Computers, Thermal Management, Computer software / hardware, Displays, Cooling
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Unmanned SkyTote Demonstrates Capabilities

AFRL scientists are working on SkyTote, a novel unmanned air vehicle (UAV) that will take off and land vertically like a helicopter (see figure) but also transition into horizontal flight like a conventional aircraft. SkyTote's primary mission is to deliver a payload to a specific point within a tactically relevant range and time. AeroVironment, Inc., of Monrovia, California, developed the vehicle under a Small Business Innovation Research effort for AFRL.

Posted in: Briefs, Mechanical Components
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The Propulsion - Safety, Affordability, and Readiness Program

Propulsion - Safety, Affordability, and Readiness (P-SAR) is a new and unique program effort intended to achieve common engine sustainment goals across the Army, Navy, and Air Force aircraft fleets (see figure). Originally conceived as a follow-on to the highly successful High-Cycle Fatigue (HCF) program, P-SAR is evolving into a benchmark collaboration initiative that includes all Department of Defense (DoD) propulsion organizations, as well as National Aeronautics and Space Administration representatives and turbine engine original equipment manufacturers.

Posted in: Briefs, Mechanical Components
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Film Cooling Using Pulsed Coolant

Turbine engine designers routinely use film cooling to cool engine components in the hot-gas flowpath. Film cooling is the process of injecting coolant fluid at one or more discrete locations along a surface exposed to a harsh, high-temperature environment. The film cools and thus protects turbine engine components, enabling the engine's operation at higher turbine inlet temperatures and increasing its thermal efficiency. Current turbine engine designs employ a continuous coolant flow, typically diverting 20%- 25% of the compressor's high-pressure air to cool turbine airfoils. By reducing the volume of high-pressure air needed for turbine blade cooling, designers can proportionately increase the flow available for combustion and thus increase thrust. Therefore, coolant flow reduction is an important design goal in the development of advanced turbine engines.

Posted in: Briefs, Mechanical Components
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Textile Capacitor

The Air Force (AF) is evolving from a Cold War-era force with a large, containment- focused infrastructure to a smaller, more responsive and affordable Air and Space Expeditionary Force. In support of this transformation, AFRL is developing affordable, sustainable, and scalable force applications, including directed energy weapons, kinetic energy weapons, electromagnetic guns and launchers, and high-power microwaves.

Posted in: Briefs, Electronics & Computers
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Nonchromated Treatment for Aluminum Surfaces

AFRL scientists and engineers recently completed development of a nonchromated treatment for aluminum aircraft surfaces and structures. The new treatment method is the result of a collaborative effort between AFRL, Boeing Phantom Works, and the Aeronautical Systems Center's Aging Aircraft Systems Squadron (ASC/AASS). The development of a non-chromatebased aluminum conversion coating fulfills one of several Air Force (AF) initiatives intended to provide aircraft manufacturers and maintainers with an environmentally safe corrosion protection method. Conversion coating is a metal finishing process that involves the application of a coating to a base metal to increase corrosion resistance and prepare the surface for additional coatings.

Posted in: Briefs, Materials
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Ground-Penetrating Radar

AFRL engineers used prototypes of recently developed ground-penetrating radar (GPR) and electronic cone penetrometer (ECP) devices to determine whether voids and anomalies in a particular airfield's subsoil were facilitating crack formation in an aircraft runway. Using the data collected during their Langley Air Force Base (AFB), Virginia, investigation, they were able both to determine the extent (and, in some cases, the cause) of the subsoil deterioration and to provide several recommendations for repairing abnormal or weakened portions of the runway. This field investigation also provided valuable information about the AFRL-developed prototype inspection devices; the evaluation results will aid designers in further refining these developmental products.

Posted in: Briefs, Materials
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Materials Knowledge Base

A team of scientists, engineers, and developers from AFRL and RJ Lee Group, Inc., recently completed functional prototype development of the Materials Knowledge Base (MKB), an object-based data repository for laboratory materials characterization information. Constructed as part of a Small Business Innovation Research (SBIR) Phase II contract, MKB demonstrates enormous potential to affect the way data collection, processing, storage, and sharing occurs. The prototype knowledge base and data management system supports AFRL's aerospace materials research and development efforts, paving the way for unprecedented project collaboration and data accessibility that the development team believes will revolutionize the way AFRL scientists and engineers collect, process, store, and share materialsrelated data.

Posted in: Briefs, Materials
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Patterned Gallium Arsenide Devices for Infrared Countermeasures

The US Air Force has a need for improved tunable laser sources—both in the midinfrared region, for developing infrared countermeasure (IRCM) applications, and in the longinfrared region, for addressing an increasing variety of threat sensors. Since few direct lasers exist in these spectral regions, scientists generally use nonlinear frequency conversion techniques to convert the output of available lasers into the desired longer

wavelengths.

Posted in: Briefs, Photonics
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AFRL Study Defines Standards for Low-Level Chemical Agent Exposure

Results of a 5-year, $40 million effort to study chemical warfare agents will benefit military and civilian personnel alike, helping leaders in both arenas cope with events should a terrorist or combat attack that exposes people to toxic chemical agents occur. Dr. Stephen Channel, an AFRL research veterinarian and toxicologist, is heading the collaborative research effort between AFRL and US Army scientists. Based at the Army's Medical Research Institute of Chemical Defense and the Edgewood Chemical and Biological Center at the Army's Aberdeen Proving Grounds, Maryland, the work is in its final year.

Posted in: Briefs, Medical
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