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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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All sources NASA NTRS DOE OSTI

DOE OSTI2021

Elucidating the Location of Cd 2+ in Post-synthetically Treated InP Quantum Dots Using Dynamic Nuclear Polarization 31 P and 113 Cd Solid-State NMR Spectroscopy

Indium phosphide quantum dots (InP QD) are a promising alternative to traditional QD materials that contain toxic heavy elements such as lead and cadmium. However, InP QD obtained from colloidal synthesis are often plagued by poor photoluminescence quantum yields (PL-QYs). In order to improve the PL-QY of InP QD, a number of post-synthetic treatments have been devised. Recently, it has been shown that InP post-synthetically treated with Lewis acid metal divalent cations (M-InP) exhibit enhanced PL-QY; however, the molecular structure and mechanism behind the improved PL-QY are not fully understood. Here, to determine the surface structure of M-InP QD, dynamic nuclear polarization surface-enhanced nuclear magnetic resonance spectroscopy (DNP SENS) experiments were employed on a series of InP magic size clusters treated with Cd ions, InP QD, cadmium phosphide (Cd 3 P 2 ) QD, and Cd-treated InP QD (Cd–InP QD). With the use of DNP SENS, we were able to obtain the 1D 31 P and 113 Cd NMR spectra, 113 Cd{ 31 P} rotational-echo double-resonance (REDOR) NMR spectra, and 31 P{ 113 Cd} dipolar heteronuclear multiple quantum correlation (D-HMQC) sequence. Changes in the phosphide 31 P chemical shifts after Cd treatment provide indirect evidence that some Cd alloys into the sub-surface regions of the particle. DNP-enhanced 113 Cd solid-state NMR spectra suggest that most Cd ions are coordinated by oxygen atoms from either carboxylate ligands or surface phosphate groups. 113 Cd{ 31 P} REDOR and 31 P{ 113 Cd} D-HMQC experiments confirm that a subset of Cd ions are located on the surface of Cd–InP QD and coordinated with phosphate groups.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2022

A universal co-solvent dilution strategy enables facile and cost-effective fabrication of perovskite photovoltaics

Cost management and toxic waste generation are two key issues that must be addressed before the commercialization of perovskite optoelectronic devices. We report a groundbreaking strategy for eco-friendly and cost-effective fabrication of highly efficient perovskite solar cells. This strategy involves the usage of a high volatility co-solvent, which dilutes perovskite precursors to a lower concentration (<0.5 M) while retaining similar film quality and device performance as a high concentration (>1.4 M) solution. More than 70% of toxic waste and material cost can be reduced. Mechanistic insights reveal ultra-rapid evaporation of the co-solvent together with beneficial alteration of the precursor colloidal chemistry upon dilution with co-solvent, which in-situ studies and theoretical simulations confirm. The co-solvent tuned precursor colloidal properties also contribute to the enhancement of the stability of precursor solution, which extends its processing window thus minimizing the waste. This strategy is universally successful across different perovskite compositions, and scales from small devices to large-scale modules using industrial spin-coating, potentially easing the lab-to-fab translation of perovskite technologies.

36 MATERIALS SCIENCE↗

NASA NTRS1975

A study of the effects on mice of smoke and gases from controlled fires in simulated aircraft cabins

Male Swiss albino mice were exposed to the pyrolysis products of two fire-retardant materials, a chlorinated aromatic polyamide and a copolymer of vinylidine fluoride and hexafluoropropene. Comparison tests were made with cotton and a 50/50 cotton-polyester composite. In addition, tests were conducted under the presence of CO, and mice were injected intraperitoneally or intramuscularly with aqueous solutions containing dissolved effluents from the pyrolysis of cotton or of chlorinated aromatic polyamide. Results indicate that unique thermodecomposition products of the polymeric materials are more toxic to mice than are other products from cotton under similar controlled conditions.

Moreci, A. P.↗

NASA NTRS1990

Past experience Skylab mission

The design of the Skylab missions, 1973 to 1974, was intended to exclude any direct handling of hazardous, toxic, or reactive materials. The materials processing facility and multipurpose furnace provided a contained environment for conducting metals melting, brazing, sphere forming, and crystal growth experiments. At the end of the third mission, following the completion of all other experiments, the materials processing facility was used for a series of flammability experiments. The flammability tests were done last because of the contamination expected from the burning of the materials within the facility. The flammability tests demonstrated a number of peculiar effects that have implications for future design (fire detection, location, and suppression/control). Although the results of the flammability tests contain lessons appropriate to planning, a number of events during the flight illustrate situations or conditions that pose considerations beyond the commonly accepted range of concern for safety-related matters. This presentation includes a discussion of: Skylab flammability studies and the implications for fire suppression/control; false fire alarms and the Skylab fire detection system; space environmental effects on materials that are normally benign; spills/release of contaminants; the detrimental effect that the release of non-hazardous materials have on detection systems; and the problem of locating sources/originating point of hazards.

Pogue, William↗

NASA NTRS1993

Monolithic Continuous-Flow Bioreactors

Monolithic ceramic matrices containing many small flow passages useful as continuous-flow bioreactors. Ceramic matrix containing passages made by extruding and firing suitable ceramic. Pores in matrix provide attachment medium for film of cells and allow free movement of solution. Material one not toxic to micro-organisms grown in reactor. In reactor, liquid nutrients flow over, and liquid reaction products flow from, cell culture immobilized in one set of channels while oxygen flows to, and gaseous reaction products flow from, culture in adjacent set of passages. Cells live on inner surfaces containing flowing nutrient and in pores of walls of passages. Ready access to nutrients and oxygen in channels. They generate continuous high yield characteristic of immobilized cells, without large expenditure of energy otherwise incurred if necessary to pump nutrient solution through dense biomass as in bioreactors of other types.

Stephanopoulos, Gregory↗

NASA NTRS1992

Kennedy Space Center environmental health program

The Kennedy Space Center's environmental health organization is responsible for programs which assure its employees a healthful workplace under diverse and varied working conditions. These programs encompass the disciplines of industrial hygiene, radiation protection (health physics), and environmental sanitation/pollution control. Activities range from the routine, such as normal office work, to the highly specialized, such as the processing of highly toxic and hazardous materials.

Marmaro, G. M.↗

NASA NTRS2000

Toxicological Risks During Human Space Exploration

The goal of toxicological risk assessment of human space flight is to identify and quantify significant risks to astronaut health from air pollution inside the vehicle or habitat, and to develop a strategy for control of those risks. The approach to completing a toxicological risk assessment involves data and experience on the frequency and severity of toxicological incidents that have occurred during space flight. Control of these incidents depends on being able to understand their cause from in-flight and ground-based analysis of air samples, crew reports of air quality, and known failures in containment of toxic chemicals. Toxicological risk assessment in exploration missions must be based on an evaluation of the unique toxic hazards presented by the habitat location. For example, lunar and Martian dust must be toxicologically evaluated to determine the appropriate control measures for exploration missions. Experience with near-earth flights has shown that the toxic products from fires present the highest risk to crew health from air pollution. Systems and payload leaks also present a significant hazard. The health risk from toxicity associated with materials offgassing or accumulation of human metabolites is generally well controlled. Early tests of lunar and Martian dust simulants have shown that each posses the potential to cause fibrosis in the lung in a murine model. Toxicological risks from air pollutants in space habitats originate from many sources. A number of risks have been identified through near-earth operations; however, the evaluation of additional new risks present during exploration missions will be a challenge.

James, John T.↗

NASA NTRS1994

A Testing Service for Industry

A small isolated NASA facility provides assistance to industry in the design, testing, and operation of oxygen systems. White Sands Test Facility (WSTF) was originally established to test rocket propulsion systems for the Apollo program. The facility's role was later expanded into testing characterization, flammability and toxicity characteristics of materials. Its materials and components test methods were adopted by the American society for Testing and Materials. When research and testing results became known, industry requested assistance, and in 1980, NASA authorized WSTF to open its facility to private firms, a valuable service, as oxygen systems testing is often too expensive and too hazardous for many companies. Today, some of the best known American industries utilize White Sands testing capabilities.

Source record↗

NASA NTRS2010

Aerospace Payloads Leak Test Methodology

Pressurized and sealed aerospace payloads can leak on orbit. When dealing with toxic or hazardous materials, requirements for fluid and gas leakage rates have to be properly established, and most importantly, reliably verified using the best Nondestructive Test (NDT) method available. Such verification can be implemented through application of various leak test methods that will be the subject of this paper, with a purpose to show what approach to payload leakage rate requirement verification is taken by the National Aeronautics and Space Administration (NASA). The scope of this paper will be mostly a detailed description of 14 leak test methods recommended.

Lvovsky, Oleg↗

NASA NTRS2010

International Space Station (ISS) Internal Active Thermal Control System (IATCS) New Biocide Selection, Qualification and Implementation

The Internal Active Thermal Control System (IATCS) aboard the International Space Station (ISS) is primarily responsible for the removal of heat loads from payload and system racks. The IATCS is a water based system which works in conjunction with the EATCS (External ATCS), an ammonia based system, which are interfaced through a heat exchanger to facilitate heat transfer. On-orbit issues associated with the aqueous coolant chemistry began to occur with unexpected increases in CO2 levels in the cabin. This caused an increase in total inorganic carbon (TIC), a reduction in coolant pH, increased corrosion, and precipitation of nickel phosphate. These chemical changes were also accompanied by the growth of heterotrophic bacteria that increased risk to the system and could potentially impact crew health and safety. Studies were conducted to select a biocide to control microbial growth in the system based on requirements for disinfection at low chemical concentration (effectiveness), solubility and stability, material compatibility, low toxicity to humans, compatibility with vehicle environmental control and life support systems (ECLSS), ease of application, rapid on-orbit measurement, and removal capability. Based on these requirements, ortho-phthalaldehyde (OPA), an aromatic dialdehyde compound, was selected for qualification testing. This paper presents the OPA qualification test results, development of hardware and methodology to safely apply OPA to the system, development of a means to remove OPA, development of a rapid colorimetric test for measurement of OPA, and the OPA on-orbit performance for controlling the growth of microorganisms in the ISS IATCS since November 3, 2007.

Wilson, Mark E.↗

NASA NTRS2011

International Space Station (ISS) Internal Active Thermal Control System (IATCS) New Biocide Selection, Qualification and Implementation

Wilson, Mark E.↗

NASA NTRS2011

International Space Station (ISS) Risk Reduction Activities

As the assembly of the ISS nears completion, it is worthwhile to step back and review some of the actions pursued by the Program in recent years to reduce risk and enhance the safety and health of ISS crewmembers, visitors, and space flight participants. While the ISS requirements and initial design were intended to provide the best practicable levels of safety, it is always possible to reduce risk -- given the determination and commitment to do so. The following is a summary of some of the steps taken by the ISS Program Manager, by our International Partners, by hardware and software designers, by operational specialists, and by safety personnel to continuously enhance the safety of the ISS. While decades of work went into developing the ISS requirements, there are many things in a Program like the ISS that can only be learned through actual operational experience. These risk reduction activities can be divided into roughly three categories: (1) Areas that were initially noncompliant which have subsequently been brought into compliance or near compliance (i.e., Micrometeoroid and Orbital Debris [MMOD] protection, acoustics) (2) Areas where initial design requirements were eventually considered inadequate and were subsequently augmented (i.e., Toxicity Level 4 materials, emergency hardware and procedures) (3) Areas where risks were initially underestimated, and have subsequently been addressed through additional mitigation (i.e., Extravehicular Activity [EVA] sharp edges, plasma shock hazards) Due to the hard work and cooperation of many parties working together across the span of nearly a decade, the ISS is now a safer and healthier environment for our crew, in many cases exceeding the risk reduction targets inherent in the intent of the original design. It will provide a safe and stable platform for utilization and discovery.

Fodroci, Michael↗

NASA NTRS2011

An Earthling to an Astronaut: Medical Challenges

Humans can travel safely into space in low Earth orbit (LEO) or to near-Earth objects if several medical, physiological, environmental, and human factors issues risks are mitigated. Research must be performed in order to set standards in these four areas, and current NASA standards are contained in the Space Flight Human System Standards volumes 1 and 2, and crew medical certification standards. These three sets of standards drive all of the clinical, biomedical research and environmental technology development for the NASA human space flight program. These standards also drive the identification of specific risks to crew health and safety, and we currently manage 65 human system risks within the human space flight program. Each risk has a specific program of research, technology development, and development of operational procedures to mitigate the risks. Some of the more important risks tat will be discussed in this talk include exposure to radiation, behavioral health due to confinement in a closed cabin, physiological changes such as loss of bone, muscle and exercise capability, reduction in immune system capability, environmental threats of maintaining an adequate atmosphere and water for drinking, avoidance of toxic or infectious material, protection of hearing, and human factors issues of equipment and task design. A nutritious and varied food supply must also be provided. All of these risks will be discussed and current strategies for mitigating these risks for long-duration human space flight. In mitigating these 65 human system risks, novel approaches to problem solving must be employed to find the most appropriate research and technology based applications. Some risk mitigations are developed internally to NASA while others are found through research grants, technology procurements, and more recently open innovation techniques to seek solutions from the global technical community. Examples and results will be presented from all of these approaches including the more recent use of prizes to stimulate innovation.

Davis, Jeffrey R.↗

NASA NTRS2005

Materials Control for Aerospace Applications

The distant future of mankind and the ultimate survivability of the human race, as it is known today, will depend on mans' ability to break earthly bonds and establish new territorial positions throughout the universe. Man must therefore be positioned to not only travel to, but also, to readily adapt to numerous and varying environments. For this mass migration across the galaxies nothing is as import to the human race as is NASA's future missions into Low Earth Orbit (LEO), to the moon, and/or Mars. These missions will form the building blocks to eternity for mankind. From these missions, NASA will develop the foundations for these building blocks based on sound engineering and scientific principles, both known and yet to be discovered. The integrity of the program will lead to development, tracking and control of the most basic elements of hardware production: That being development and control of applications of space flight materials. Choosing the right material for design purposes involves many considerations, such as governmental regulations associated with manufacturing operations, both safety of usage and of manufacturing, general material usage requirements, material longevity and performance requirements, material interfacing compatibility and material usage environments. Material performance is subject to environmental considerations in as much as a given material may perform exceptionally well at standard temperatures and pressures while performing poorly under non-standard conditions. These concerns may be found true for materials relative to the extreme temperatures and vacuum gradients of high altitude usage. The only way to assure that flight worthy materials are used in design is through testing. However, as with all testing, it requires both time on schedule and cost to the operation. One alternative to this high cost testing approach is to rely on a materials control system established by NASA. The NASA community relies on the MAPTIS materials control system founded at MSFC and supported by the other NASA Centers. This system is a data bank of all materials used in space flight operations. These materials are rated for several characteristics that are common concerns in high altitude or deep space usage: Odor, off gassing, material fluid compatibility, toxicity, corrosion susceptibility, stress corrosion susceptibility, etc.

Ferguson, Michael↗

DOE OSTI2020

Biocatalysts for conversion of thermochemical waste streams

Disclosed herein are microorganisms that have enhanced tolerance to toxic compounds found in thermochemical waste streams. Methods of utilizing carbon found in waste streams are also disclosed. Also presented herein are methods for detoxifying waste streams and methods of bioconversion of toxic waste stream materials into useful products.

Jayakody, Thelhawadigedara Lahiru Niroshan↗

DOE OSTI2023

Biological toxicity and environmental hazards associated with PLGA nanoparticles

There have been tremendous advances in nanotechnology. More recently, the use of nanoparticles has expanded to applications including materials, packaging, energy, and medical uses such as drug delivery, diagnostics, and therapeutics. The American Society for Testing and Materials (ASTM) and the International Organization for Standardization (ISO) define nanoparticles as particles with at least one dimension measuring between 1 and 100 nm (2), but this view is generally too limited, and recommendations have been made to consider all materials with a dimension measuring under 1,000 nm as nanoparticles. The biomedical uses of nanoparticles are particularly promising because of their ability to reach and target various sites and organs. However, some nanoparticles can be composed of toxic materials or are limited by issues of biodistribution and bioaccumulation, which have hampered their use in biomedicine. The copolymer poly lactic-co-glycolic acid (PLGA) has gained use in biomedical applications as a delivery system because it is considered biocompatible and can be formulated with controlled degradation in physiological environments. PLGA has a history in biomedicine that dates to the 1970s when biodegradable sutures were developed using PLGA. In addition, the United States (US) Food and Drug Administration (FDA) and the European Medicine Agency (EMA) have approved various PLGA particle formulations as therapeutic delivery vehicles. Interest in biocompatible materials to deliver a range of therapeutic drugs, proteins, nucleic acids, and other molecules has risen recently. In addition to drug delivery, sustained drug release can be achieved by tuning the physical properties of PLGA, such as the molecular weight, ratio of lactic to glycolic acid, drug concentration, stabilizing molecules, and particle size. Given the rise of nanoparticles, human and environmental exposure to them is inevitable as more applications use free, unbound, and highly mobile particles. Although PLGA is generally considered safe, a detailed understanding of how PLGA and the other components used to help formulate this copolymer into a nanoparticle delivery vehicle is useful for assessing potential harmful effects. Despite recent advances in PLGA nanoparticle formulations, residual stabilizing molecules, inconsistent preparations, and batch-to-batch variations can lead to toxicity. Poor preparations of PLGA can lead to common mechanisms of toxicity observed with nanoparticles, such as inflammation and oxidative stress. Consistency in PLGA formulations and accurate methods to evaluate nanoparticle toxicity are needed to ensure safety. In order to better assess PLGA nanoparticles as non-toxic delivery systems, it is critical to understand their physical and chemical properties and the formulation protocols that may introduce toxic components into particles.

Biology, nanoparticle, toxicity↗

NASA NTRS1995

Development of an in-line filter to prevent intrusion of NO2 toxic vapors into A/C systems

The hypergolic propellant nitrogen tetroxide (N2O4 or NTO) is routinely used in spacecraft launched at Kennedy Space Center (KSC) and Cape Canaveral Air Station (CCAS). In the case of a catastrophic failure of the spacecraft, there would be a release of the unspent propellant in the form of a toxic cloud. Inhalation of this material at downwind concentrations which may be as high as 20 parts per million (ppm) for 30 minutes in duration, may produce irritation to the eyes, nose and respiratory tract. Studies at both KSC and CCAS have shown that the indoor concentrations of N2O4 during a toxic release may range from 1 to 15 ppm and depend on the air change rate (ACR) for a particular building and whether or not the air conditioning (A/C) system has been shut down or left in an operating mode. This project was initiated in order to assess how current A/C systems could be easily modified to prevent personnel from being exposed to toxic vapors. A sample system has been constructed to test the ability of several types of filter material to capture the N2O4 vapors prior to their infiltration into the A/C system. Test results will be presented which compare the efficiencies of standard A/C filters, water wash systems, and chemically impregnated filter material in taking toxic vapors out of the incoming air stream.

Meneghelli, Barry↗

NASA NTRS1977

Study to develop improved fire resistant aircraft passenger seat materials, phase 1

The procurement and testing of a wide range of candidate materials is reported. Improved fire resistant nonmetallic materials were subjected to tests to evaluate their thermal characteristics, such as burn, smoke generation, heat release rate and toxicity. In addition, candidate materials were evaluated for mechanical, physical and aesthetic properties. Other properties considered included safety, comfort, durability and maintainability. The fiscal year 1977 and the projected 1980 cost data were obtained for aircraft seat materials.

Trabold, E. L.↗