Materials & Coatings

A Computer Model for Analyzing Volatile Removal Assembly

A computer model simulates reactional gas/liquid two-phase flow processes in porous media. A typical process is the oxygen/wastewater flow in the Volatile Removal Assembly (VRA) in the Closed Environment Life Support System (CELSS) installed in the International Space Station (ISS). The volatile organics in the wastewater are combusted by oxygen gas to form clean water and carbon dioxide, which is solved in the water phase. The model predicts the oxygen gas concentration profile in the reactor, which is an indicator of reactor performance.

Posted in: Briefs, TSP, Materials, Computational fluid dynamics, Water reclamation, Life support systems, Gases, Oxygen

Thermographic Printing Using Organic Silver Salts

Light-sensitive and light-insensitive materials generate black and white images by the use of heat; no ink is required.

The materials presented allow the writing on a single sheet of these materials without ink, but only by heat, thereby revealing a black and white image. This process is called thermographic writing or printing.

Posted in: Briefs, MDB, Briefs, Coatings & Adhesives, Materials, Bio-Medical, Diagnostics, Medical, Heat treatment, Materials properties

Repeatable, Low-Cost UV Assembly of Biosensors

UV spot curing system ensures greater accuracy for automated and manual manufacturing of biosensors.

A biosensor is an analytical device that converts a biological response into an electrical signal. It is increasingly being used as a cost-effective diagnostic tool that offers the capability to render efficient, easy-to-use, and accurate diagnosis. While technological advances in biosensors are allowing this technology to cater to an extensive range of applications in a number of fields, such as industrial and environmental testing, the largest applications have been in the healthcare sector, including glucose detection, pregnancy testing, blood testing, breath analyzers, and cancer diagnosis.

Posted in: Briefs, MDB, Briefs, Manufacturing & Prototyping, Coatings & Adhesives, Materials, Bio-Medical, Medical, Patient Monitoring, Sensors, Sensors and actuators, Sensors and actuators, Biological sciences, Assembling

Lithium-Ion Electrolytes Containing Phosphorous-Based, Flame-Retardant Additives

This technology can enhance the safety of lithium-ion batteries for portable electronic devices and hybrid electric vehicles.

Future NASA missions aimed at exploring Mars, the Moon, and the outer planets require rechargeable batteries that can operate over a wide temperature range (–60 to +60 °C) to satisfy the requirements of various applications. In addition, many of these applications will require improved safety, due to their use by humans. Currently, the state-of-the-art lithium-ion (Li-ion) system has been demonstrated to operate over a wide range of temperatures (–40 to +40 °C); however, abuse conditions can often lead to cell rupture and fire. The nature of the electrolyte can greatly affect the propensity of the cell/battery to catch fire, given the flammability of the organic solvents used within.

Posted in: Briefs, Materials, Battery cell chemistry, Lithium-ion batteries, Battery cell chemistry, Lithium-ion batteries, Electrolytes, Fire prevention

Straight-Pore Microfilter With Efficient Regeneration

A novel, high-efficiency gas particulate filter has precise particle size screening, low pressure drop, and a simple and fast regeneration process. The regeneration process, which requires minimal material and energy consumption, can be completely automated, and the filtration performance can be restored within a very short period of time.

Posted in: Briefs, TSP, Materials, Maintenance, Repair and Service Operations, Maintenance, repair, and service operations, Particulate filters

Determining Shear Stress Distribution in a Laminate

The simplified shear solution does not require solution of a particular boundary value problem.

A “simplified shear solution” method approximates the through-thickness shear stress distribution within a composite laminate based on an extension of laminated beam theory. The method does not consider the solution of a particular boundary value problem; rather, it requires only knowledge of the global shear loading, geometry, and material properties of the laminate or panel. It is thus analogous to lamination theory in that ply-level stresses can be efficiently determined from global load resultants at a given location in a structure and used to evaluate the margin of safety on a ply-by-ply basis. The simplified shear solution stress distribution is zero at free surfaces, continuous at ply boundaries, and integrates to the applied shear load. The method has been incorporated within the HyperSizer® commercial structural sizing software to improve its predictive capability for designing composite structures.

Posted in: Briefs, TSP, Materials, Composite materials, Materials properties, Durability, Durability, Test procedures

InGaP Heterojunction Barrier Solar Cells

Nanostructured cells could enhance the performance of terrestrial high-efficiency solar cells.

A new solar-cell structure utilizes a single, ultra-wide well of either gallium arsenide (GaAs) or indium-galliumphosphide (InGaP) in the depletion region of a wide bandgap matrix, instead of the usual multiple quantum well layers. These InGaP barrier layers are effective at reducing diode dark current, and photogenerated carrier escape is maximized by the proper design of the electric field and barrier profile. With the new material, open-circuit voltage enhancements of 40 and 100 mV (versus PIN control systems) are possible without any degradation in short-circuit current.

Posted in: Briefs, TSP, Materials, Solar energy, Alloys, Materials properties

Low-Outgassing Adhesives

Applications include solar panels, LEDs, and medical devices.

Products and manufacturing processes can be sensitive to outgassed chemical compounds, resulting in the use of adhesives, encapsulants, and sealants that have been specially formulated for low-outgassing performance. The most stringent outgassing requirements are best met by products formulated to pass an industry-standard outgassing test known as ASTM E595-07. Low-outgassing adhesives don’t typically require any sacrifice in other mechanical or physical properties. What sets low-outgassing products apart from their generic counterparts is that the low-outgassing grades have passed the ASTM test.

Posted in: Briefs, Materials, Adhesives and sealants, Chemicals, Gases, Materials properties

Functionalization of Single-Wall Carbon Nanotubes by Photo-Oxidation

A new technique for carbon nanotube oxidation was developed based upon the photo-oxidation of organic compounds. The resulting method is more benign than conventional oxidation approaches and produces single-wall carbon nanotubes (SWCNTs) with higher levels of oxidation.

Posted in: Briefs, TSP, Materials, Chemicals, Nanotechnology, Oxygen

Ultra-High-Molecular-Weight Polyethylene Technology for Minimally Invasive Devices

Ultra-thin film and fiber are suitable for implantable cardiovascular devices.

Ultra-high-molecular-weight polyethylene (UHMWPE) has been used for decades as a biomaterial in joint replacements. Recently, this technology was refined to serve the needs of minimally invasive surgical applications, particularly cardiovascular implants. UHMWPE fiber can be shaped into a range of textile constructions, including braids and woven tubes, while the film can be used as a very thin barrier or cover. As such, the medical-grade UHMWPE film and fiber are suitable for enhancing the design of various implantable cardiovascular devices, including stent grafts and covered stents.

Posted in: Briefs, MDB, Briefs, Coatings & Adhesives, Materials, Bio-Medical, Implants & Prosthetics, Medical, Cardiovascular system, Prostheses and implants, Fibers, Polymers

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