Special Coverage

Supercomputer Cooling System Uses Refrigerant to Replace Water
Computer Chips Calculate and Store in an Integrated Unit
Electron-to-Photon Communication for Quantum Computing
Mechanoresponsive Healing Polymers
Variable Permeability Magnetometer Systems and Methods for Aerospace Applications
Evaluation Standard for Robotic Research
Small Robot Has Outstanding Vertical Agility
Smart Optical Material Characterization System and Method
Lightweight, Flexible Thermal Protection System for Fire Protection
Nasa Tech Briefs

Material Combination Enables Transistor Gate Length of 1 Nanometer

The laws of physics have set a 5-nanometer threshold on the size of transistor gates among conventional semiconductors, about one-quarter the size of high-end, 20-nanometer-gate transistors now on the market. Researchers from the Department of Energy's Lawrence Berkeley National Laboratory have created a transistor with a working 1-nanometer gate.

Posted in: Briefs, Electronics & Computers, Downsizing, Transistors, Nanomaterials, Semiconductors

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Standardized Heating Method to Trigger and Prevent Thermal Runaway Propagation in Lithium-Ion Batteries

Lithium-ion (Li-ion) cells are increasingly used in high-voltage and high-capacity modules. The Li-ion chemistry has the highest energy density of all rechargeable battery chemistries, but associated with that energy is the issue of catastrophic thermal runaway with a fire. With recent incidents in the commercial aerospace and electronics sectors, methods are required to prevent cell-to-cell thermal runaway propagation. The goal of this work was to achieve a common method for triggering a single cell in a Li-ion battery module into thermal runaway, determine if one can consistently obtain this thermal runaway event, and design mitigation measures to address propagation of the thermal runaway to other cells in the module.

Posted in: Briefs, Energy, Battery cell chemistry, Lithium-ion batteries, Fire prevention, Risk assessments

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Micro-Lid for Sealing a Sample Reservoir for Micro-Extraction Systems

Improved micro-extraction systems could be useful for military remote sensing using microfluidics.Great strides are taken to miniaturize spaceflight instrumentation, particularly analytical systems such as liquid chromatographs, gas chromatographs, and mass spectrometers. With miniaturization of instruments, large amounts of samples are no longer required. Therefore, a lesser quantity of sample from the environment needs to be acquired and extracted. Current practices of sample extraction are large in volume and consume an enormous amount of power, which is inconsistent for microfluidic instruments in development. These consume minute amounts of power and are of low mass. There have been efforts to create micro-sample extraction systems; however, a downfall of those systems is the inability to automatically close sample reservoirs.

Posted in: Briefs, Mechanical Components, Mechanics, Containers, Seals and gaskets, Test equipment and instrumentation, Spacecraft

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Products of Tomorrow: March 2017

This column presents technologies that have applications in commercial areas, possibly creating the products of tomorrow. To learn more about each technology, see the contact information provided for that innovation.

Posted in: Articles, Manufacturing & Prototyping, Product development, Research and development

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Single-Fluid-Pumped Radiators with Increased Turn-Down Ratio and Control in the Stagnation Regime

The system trades mass-optimized heat rejection for a human-rated, single-fluid pumped system of greater heat rejection range and passive control.Fluid-pumped radiators are used to reject heat from structures to space. A fluid travels inside the structure to collect heat, and then travels external to the structure through radiators where the heat is rejected to space via radiation heat transfer. A radiator is essentially several tubes attached to a thermally conducting plate or face sheet. The fluid cools as it travels along the inside of the tubes, and then returns to the inside of the structure to repeat the heat rejection cycle. If the structure contains humans, the fluid in the structure must be nontoxic and nonflammable. Further, as space can be extremely cold (4 K), the fluid external to the structure may freeze, particularly during low-power operations where heat rejection needs are minimal. Freezing of the fluid renders the radiator inoperable, and unfreezing a radiator can be very difficult, power-intensive (i.e. heaters), and/or timely. For these reasons, two fluids may be used: one inside that is compatible with humans (e.g. water), and one outside that has a low freezing point (e.g. ammonia). The heat is then transferred from the inner loop to the external loop through a heat exchanger. This dual-loop system is more complex and heavier than a single-loop system. However, as the outer loop does not freeze as easily, the dual-loop radiator system can be operated at lower heat rejection loads, increasing its overall heat rejection range (or turn-down ratio) over that of the single-loop system.

Posted in: Briefs, Mechanical Components, Mechanics, Heat exchangers, Heat transfer, Radiators

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Silicon Micro-Emitters for Microfluidic Electrospray Propulsion Systems

Advances in microfabrication capabilities are enabling the development of micro-needles for highly compact electrospray systems.JPL's Microfluidic Electrospray Propulsion (MEP) thruster design is based on a microfabricated electrospray system with a capillary-force-driven feed system that uses indium metal as the propellant. This architecture provides an extremely compact, modular system scalable to a wide range of applications from micro spacecraft to large, space-based telescopes.

Posted in: Briefs, Manufacturing & Prototyping, Architecture, Microelectromechanical devices, Propellants, Spacecraft fuel, Silicon alloys

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Hybrid Flow Control Method for Simple Hinged Flap High-Lift System

This approach combines sweeping jet actuators for active flow control and adaptive vortex generators for passive flow control.NASA's Langley Research Center has created a novel process that significantly improves the effectiveness of high-lift devices on aircraft wings by utilizing a hybrid concept of both sweeping jet (SWJ) actuators for active flow control (AFC) and adaptive vortex generators (AVGs) for passive flow control. High-lift technology reshapes aircraft wings for more lift during takeoff and landing. Conventional high-lift devices are complex and employ a significant number of parts. In addition, these complex mechanical high-lift systems (e.g., Fowler flap mechanisms) often protrude externally under the wings, resulting in increased cruise drag. Simple hinged flaps are preferable high-lift devices for low-drag cruise performance, but they are vulnerable to flow separation at high flap deflections for both trailing edge and leading edge applications. This innovation achieves higher flap deflections without flow separation while minimizing the pneumatic power requirement of AFC.

Posted in: Briefs, Aeronautics, Aerospace, Wings, Electronic control systems, Sensors and actuators, Performance upgrades

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