Materials & Coatings

Biotic-Abiotic Interface Between the Body and an Artificial Limb

A modified titanium construct and specially machined surface increase adherence of tissue to a prosthetic limb.

Because of its high mechanical properties, chemical stability, and biocompatibility, titanium is a commonly used material in dental and orthopedic applications. Its excellent biocompatibility allows titanium implants to be directly anchored to bone, or osseo-integrated. The conventional prosthetic replacement in amputees is a stump-socket design, which transfers forces through the prosthetic to an external contact point on the patient. Such a design results in non-uniform distribution of pressure, and can lead to pain, infection, and necrosis of the soft tissues at the point of contact.

Posted in: MDB, Briefs, TSP, Coatings & Adhesives, Materials, Bio-Medical, Implants & Prosthetics, Medical, Prostheses and implants, Materials properties, Titanium, Biomechanics

Optimizing a Laser Process for Making Carbon Nanotubes

Trends in process parameters for optimization and scale-up have been identified.

A systematic experimental study has been performed to determine the effects of each of the operating conditions in a double-pulse laser ablation process that is used to produce single-wall carbon nanotubes (SWCNTs). The comprehensive data compiled in this study have been analyzed to recommend conditions for optimizing the process and scaling up the process for mass production.

Posted in: Briefs, TSP, Materials, Optimization, Lasers, Lasers, Fabrication, Production engineering, Nanomaterials

Thermogravimetric Analysis of Single-Wall Carbon Nanotubes

 An improved protocol yields greater consistency.

An improved protocol for thermo-gravimetric analysis (TGA) of samples of single-wall carbon nanotube (SWCNT) material has been developed to increase the degree of consistency among results so that meaningful comparisons can be made among different samples. This improved TGA protocol is suitable for incorporation into the protocol for characterization of carbon nanotube material as described in the preceding article.

Posted in: Briefs, TSP, Materials, Materials properties, Nanomaterials, Test procedures, Thermal testing

Database for Safety-Oriented Tracking of Chemicals

SafetyChem is a computer program that maintains a relational database for tracking chemicals and associated hazards at Johnson Space Center (JSC) by use of a Web-based graphical user interface. The SafetyChem database is accessible to authorized users via a JSC intranet. All new chemicals pass through a safety office, where information on hazards, required personal protective equipment (PPE), fire-protection warnings, and target organ effects (TOEs) is extracted from material safety data sheets (MSDSs) and recorded in the database.

Posted in: Briefs, Materials

Optimized Li-Ion Electrolytes Containing Fluorinated Ester Co-Solvents

Resulting rechargeable batteries could be used in consumer electronics, electric cars, and scientific instrumentation in extreme environments.

A number of experimental lithium-ion cells, consisting of MCMB (meso-carbon microbeads) carbon anodes and LiNi0.8Co0.2O2 cathodes, have been fabricated with increased safety and expanded capability. These cells serve to verify and demonstrate the reversibility, low-temperature performance, and electrochemical aspects of each electrode as determined from a number of electrochemical characterization techniques. A number of Li-ion electrolytes possessing fluorinated ester co-solvents, namely trifluoroethyl butyrate (TFEB) and trifluoroethyl propionate (TFEP), were demonstrated to deliver good performance over a wide temperature range in experimental lithium-ion cells.

Posted in: Briefs, TSP, Materials, Battery cell chemistry, Lithium-ion batteries, Battery cell chemistry, Lithium-ion batteries, Electrolytes, Materials properties

Probabilistic Multi-Factor Interaction Model for Complex Material Behavior

Complex material behavior is represented by a single equation of product form.

Complex material behavior is represented by a single equation of product form to account for interaction among the various factors. The factors are selected by the physics of the problem and the environment that the model is to represent. For example, different factors will be required for each to represent temperature, moisture, erosion, corrosion, etc. It is important that the equation represent the physics of the behavior in its entirety accurately.

Posted in: Briefs, Materials, Mathematical models, Materials properties

Particle Distribution on Webs or Cloths

This technology provides the ability to uniformly distribute and attach particulate matter onto fibrous composite sheet or web materials.

This technology provides a methodology and products that are formed from fibrous substrates or film-like surfaces by uniform impregnation with a particulate that is subsequently firmly attached. The extremely uniform distribution of the particulate is accomplished by 1) electrically charging a fibrous matrix with individual exposed surfaces to create a uniform distribution of charged sites; 2) applying particulates to this matrix so that particulates adhere at the charged sites; and 3) the particulates are attached to the individual fibers within the substrate by firm non-transient bonding.

Posted in: Briefs, MDB, Briefs, Manufacturing & Prototyping, Coatings & Adhesives, Materials, Bio-Medical, Medical, Medical equipment and supplies, Fabrics, Fibers, Materials properties

Hollow Radiopaque Bioactive Microspheres Carry Drugs in Embolization Procedures

Combining embolization therapy with localized drug delivery, application of biomaterials is more effective.

The number of applications of synthetic biomaterials continues to expand. However, the imaging of injected biomaterials is important to control the treatment procedure in real time, to avoid complications, and to assess therapeutic success. Embolization is the obstruction of the blood flow in a vessel that can be an effective treatment for tumors in hepatocellular carcinoma or for uterine fibroids. By combining this embolization therapy with a localized drug delivery, the treatment can even be more effective. The material that is currently used is not radiopaque and can therefore cause difficulties for the interventional radiologist during placement of the embolic. Therefore, hollow, drug-carrying microspheres were made radiopaque.

Posted in: Briefs, MDB, Briefs, Coatings & Adhesives, Materials, Bio-Medical, Drug Delivery, Medical, Diseases, Biomaterials, Pharmaceuticals, Polymers

Liquid Cooling/Warming Garment

This lightweight garment can be used by firefighters, soldiers, and personnel working with hazardous materials.

The NASA liquid cooling/ventilating garment (LCVG) currently in use was developed over 40 years ago. With the commencement of a greater number of extra-vehicular activity (EVA) procedures with the construction of the International Space Station, problems of astronaut comfort, as well as the reduction of the consumption of energy, became more salient.

Posted in: Briefs, MDB, Briefs, Coatings & Adhesives, Materials, Bio-Medical, Medical, Patient Monitoring, Human factors, Spacesuits

Tissuelike 3D Assemblies of Human Broncho-Epithelial Cells

Experimental conditions are more realistic than those of 2D monolayer cell cultures.

Three-dimensional (3D) tissuelike assemblies (TLAs) of human bronchoepithelial (HBE) cells have been developed for use in in vitro research on infection of humans by respiratory viruses. The 2D monolayer HBE cell cultures heretofore used in such research lack the complex cell structures and interactions characteristic of in vivo tissues and, consequently, do not adequately emulate the infection dynamics of in-vivo microbial adhesion and invasion. In contrast, the 3D HBE TLAs are characterized by more-realistic reproductions of the geometrical and functional complexity, differentiation of cells, cell-to-cell interactions, and cell-to-matrix interactions characteristic of human respiratory epithelia. Hence, the 3D HBE TLAs are expected to make it possible to perform at least some of the research in vitro under more-realistic conditions, without need to infect human subjects.

Posted in: Briefs, MDB, TSP, Briefs, TSP, Coatings & Adhesives, Materials, Bio-Medical, Medical, Scale models, Anatomy, Biological sciences, Diseases, Test equipment and instrumentation

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