Special Coverage

Technique Provides Security for Multi-Robot Systems
Bringing New Vision to Laser Material Processing Systems
NASA Tests Lasers’ Ability to Transmit Data from Space
Converting from Hydraulic Cylinders to Electric Actuators
Automating Optimization and Design Tasks Across Disciplines
Vibration Tables Shake Up Aerospace and Car Testing
Supercomputer Cooling System Uses Refrigerant to Replace Water
Computer Chips Calculate and Store in an Integrated Unit
Electron-to-Photon Communication for Quantum Computing

Measurement of Oxygen with Sub-PPM

A company is searching for an innovative technology for the measurement of oxygen with sub-ppm resolution. They are seeking a continuous method of measurement or those with cycle times measured in seconds, the ability to measure within a flammable gas such as hydrogen, and a non-consumable device with a long lifetime (greater than 5 years). Oxygen shock should not damage the sensor or require special treatment to recover it.

Respond to this TechNeed at: Email: nasatech@yet2.com Phone: 781-972-0600

Posted in: NASA Tech Needs

Method for Manufacturing Controlled Open-Cell Silicone Foam

A company is looking for a method to manufacture controlled, ultra-lightweight, open-cell silicone foam. The foam cells must have very similar size, and the foam must be very elastic with a water absorption coefficient of 300-400%. The company is looking for companies able to design or to license the process for controlling temperature cycle, curing time, and other main process parameters.

Respond to this TechNeed at: Email: nasatech@yet2.com Phone: 781-972-0600

Posted in: NASA Tech Needs

Drew Feustel, Astronaut, Johnson Space Center, Houston, TX

Astronaut Drew Feustel is scheduled to fly aboard the Space Shuttle Discovery when it makes what is projected to be the final manned mission to service the Hubble Space Telescope. Feustel will perform three of the five spacewalks planned for that mission.

Posted in: Who's Who

Creating Patterned Multispectral Filters

In recent years the explosion in demand for multispectral imaging has coupled with the industry’s insatiable need for weight reduction, thereby greatly increasing the demand for more sophisticated approaches to producing optical filters that are used in these systems. One method to meet the challenge of reducing the weight of a multispectral system is to eliminate beam-splitting optics and multiple detectors by patterning a filter array on a single substrate, or directly on the CCD itself.

Posted in: Articles, Imaging, Imaging and visualization

Using ALD To Bond CNTs to Substrates and Matrices

CNT-based field emitters could be made more durable.

Atomic-layer deposition (ALD) has been shown to be effective as a means of coating carbon nanotubes (CNTs) with layers of Al2O3 that form strong bonds between the CNTs and the substrates on which the CNTs are grown. It should also be possible to form strong CNT/ substrate bonds using other coating materials that are amenable to ALD — for example, HfO2, Ti, or Ta. Further, it has been conjectured that bonds between CNTs and matrices in CNT/matrix composite materials could be strengthened by ALD of suitable coating materials on the CNTs.

Posted in: Briefs, Materials, Joining, Coatings, colorants, and finishes, Nanomaterials

Alternating-Composition Layered Ceramic Barrier Coatings

These coatings are expected to be more durable, relative to prior thermal/environmental barrier coatings.

Ceramic thermal and environmental barrier coatings (T/EBCs) that contain multiple layers of alternating chemical composition have been developed as improved means of protecting underlying components of gas-turbine and other heat engines against both corrosive combustion gases and high temperatures. A coating of this type (see figure) is configured using the following layers:

An outer, or top oxide layer that has a relatively high coefficient of thermal expansion (CTE) and serves primarily to thermally protect the underlying coating layers and the low-CTE ceramic substrate structural material (the component that is ultimately meant to be protected) from damage due to exposure at the high temperatures to be experienced in the application; An inner, or bottom silicon-containing/ silicate layer, which is in contact with the substrate, has a low CTE and serves primarily to keep environmental gases away from the substrate; and Multiple intermediate layers of alternating chemical composition (and, hence, alternating CTE).
Posted in: Briefs, TSP, Materials, Thermal management, Ceramics, Chemicals, Coatings, colorants, and finishes, Engine mechanical components

Variable-Structure Control of a Model Glider Airplane

The conventional spin-recovery technique for fuselage-heavy aircraft is implemented by a modern control system.

A variable-structure control system designed to enable a fuselage-heavy airplane to recover from spin has been demonstrated in a hand-launched, instrumented model glider airplane (see figure). It has long been known that the most effective spin recovery technique for fuselage- heavy aircraft involves the use of ailerons to roll the airplane into the spin. This technique might be considered counter-intuitive because the pro-spin aileron deflection tends to initially increase the roll-rate component of the angular momentum of the airplane. However, it restores some controllability, enabling the pilot to perform subsequent maneuvers to pull out of the spin. The design of the present model-airplane control system was inspired in part by recognition that the aforementioned (and conventional) spin-recovery technique mimics a variable-structure control law.

Posted in: Briefs, TSP, Mechanical Components, Mechanics, Adaptive control, Architecture, Attitude control, Aircraft operations, Fixed-wing aircraft, Unmanned aerial vehicles

Axial Halbach Magnetic Bearings

Complex active control systems are not needed.

Axial Halbach magnetic bearings have been investigated as part of an effort to develop increasingly reliable noncontact bearings for future high-speed rotary machines that may be used in such applications as aircraft, industrial, and land- vehicle power systems and in some medical and scientific instrumentation systems. Axial Halbach magnetic bearings are passive in the sense that unlike most other magnetic bearings that have been developed in recent years, they effect stable magnetic levitation without need for complex active control.

Posted in: Briefs, TSP, Mechanical Components, Mechanics, Magnetic materials, Bearings, Rotary engines

Compact, Non-Pneumatic Rock-Powder Samplers

Tool bits for ultrasonic/sonic drill/corers are modified to trap small particles.

Tool bits that automatically collect powdered rock, permafrost, or other hard material generated in repeated hammering action have been invented. These tool bits are intended primarily for use as parts of ultrasonic/sonic drill corers (USDCs) and related apparatuses, which have been reported in numerous prior NASA Tech Briefs articles. A USDC is based on the concept of a miniature, lightweight, low-power, piezoelectrically driven hammering mechanism that is excited with a combination of ultrasonic and sonic vibrations that enable its tool bit to bore into rock or other hard, brittle material with very little applied force. There are numerous potential applications for such apparatuses in geological exploration on Earth and on remote planets. Typically, in such an exploration, the purpose served by a USDC is to cut samples of fragmented rock from one or more depth(s).

Posted in: Briefs, Mechanical Components, Mechanics, Particulate matter (PM), Soils, Cutting, Drilling, Vibration, Test equipment and instrumentation

Biochips Containing Arrays of Carbon-Nanotube Electrodes

Small quantities of biomarkers could be detected rapidly, with simplified preparation.

Biochips containing arrays of nanoelectrodes based on multiwalled carbon nanotubes (MWCNTs) are being developed as means of ultrasensitive electrochemical detection of specific deoxyribonucleic acid (DNA) and messenger ribonucleic acid (mRNA) biomarkers for purposes of medical diagnosis and bioenvironmental monitoring. In mass production, these biochips could be relatively inexpensive (hence, disposable). These biochips would be integrated with computer-controlled microfluidic and microelectronic devices in automated hand-held and bench-top instruments that could be used to perform rapid in vitro genetic analyses with simplified preparation of samples.

Posted in: Briefs, TSP, Bio-Medical, Medical, Integrated circuits, Biological sciences, Fabrication, Nanotechnology, Test equipment and instrumentation

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