Browse Topic: Radiation protection
Graphene is a two-dimensional carbon material made of carbon by covalent bonds, where carbon atoms are arranged in a honeycomb lattice. Graphene has promising electronic and mechanical properties. There are many processes available for the formation of the graphene. CVD (Chemical Vapor Deposition) process for the formation of graphene over the metal surface is most compatible. Graphene is being investigated for its application in space electronics. In space, there are many irradiation particles and waves like x-rays, gamma rays, alpha particles, and beta particles. Single particle like neutron can create single event upset in electronic devices. Graphene can work as a radiation shielding material. Graphene-metal, graphene and epsilon near zero metamaterials structure can be used for electromagnetic wave absorbent
Two-dimensional transition metal dichalcogenides (2D-TMDs) have been proposed as novel optoelectronic materials for space applications due to their relatively light weight. MoS2 has been shown to have excellent semiconducting and photonic properties. Here, we report the effect of gamma irradiation on the structural and optical properties of a monolayer of MoS2. Louisiana State University, Baton Rouge, Louisiana Graphene is a two-dimensional carbon material made of carbon by covalent bonds, where carbon atoms are arranged in a honeycomb lattice. Graphene has promising electronic and mechanical properties. There are many processes available for the formation of the graphene. CVD (Chemical Vapor Deposition) process for the formation of graphene over the metal surface is most compatible. Graphene is being investigated for its application in space electronics. In space, there are many irradiation particles and waves like x-rays, gamma rays, alpha particles, and beta particles. Single
An ingestible x-ray dosimeter detects radiation dose in real time. Combining the novel capsule design and a neural network-based regression model that calculates radiation dose from the information captured by the capsule, researchers found that they could provide approximately five times more accurate monitoring of the dose delivered than current standard methods
This paper takes the single-phase full-bridge power converter of the power generation system of the free-piston engine of the incremental electric vehicle (EV) as the research object. By establishing the three-dimensional (3D) electromagnetic radiation simulation model of the power converter, the electromagnetic radiation field of the power converter is simulated and analyzed by using the equivalent excitation source method. The shielding and suppression effect of the power converter shell on the far-field radiated electromagnetic field and its influence on the internal electromagnetic field are analyzed. The shielding cover of the radiation source and sensitive source of the power converter is designed, and the effectiveness of the electromagnetic radiation shielding device for shielding the radiation source and sensitive source is discussed. The simulation results show that the shell of the power converter can effectively shield the far-field radiation so that the external radiation
Louisiana State University Baton Rouge, LA
Innovators at NASA’s Glenn Research Center have made several breakthroughs in treating hexagonal boron nitride (hBN) nanomaterials, improving their properties to supplant carbon nanotubes in many applications. These inventors have greatly enhanced the processes of intercalation and exfoliation. Both processes are crucial in creating usable nanomaterials and tailoring them for specific engineered applications. In addition, Glenn’s researchers have devised a means of fabricating exfoliated hBN-alumina ceramic composites, which have great potential as high-thermal-conductivity electrical insulators, as well as a new method to remove impurities from nanomaterials without causing damage to their structures. All of these advances have hBN nanomaterials set to transform applications such as heat sinks, electrical insulators, lightweight piezoelectric polymers for satellites and unmanned aerial vehicles, ceramic composites for jet engines, biomedical components, and radiation shielding
NASA Langley Research Center has developed a method to create Sequential/Simultaneous Multi-Metallized Nanocomposites (S2M2N) via supercritical fluid (SCF) sequential or simultaneous multi-metal infusion. The SCF infusion process provides deep impregnation of metal nanoparticles into a variety of materials, including those with challenging topographies and complex structures. The resulting multi-metallized nanocomposites can possess high electrical conductivity, permittivity, permeability, wear resistance/anti-penetrant, and radiation shielding along with high toughness
Over the past three years, NASA has been studying the operational effectiveness and astronaut protection efficacy of numerous radiation protection shelters for use in space exploration activities outside of Earth's magnetosphere. The work was part of NASA's Advanced Exploration Systems (AES) RadWorks Storm Shelter project. Fabricated items were integrated into mockup deep space habitat vehicle sections for operational evaluations. Two full-scale human-in-loop simulations were designed, fabricated, and implemented. The goal was to provide design and performance assessment information for consideration by mission designers who must quantify the radiation protection characteristics of their exploration trade space
This document provides an industry standard for Long Term Storage (LTS) of electronic devices by drawing from the best long term storage practices currently known. LTS is defined as any device storage for more than 12 months but typically allows for much longer (years). While intended to address the storage of unpackaged semiconductors and packaged electronic devices, nothing in this standard precludes the storage of other items under the storage levels defined herein. This standard is not intended to address built-in failure mechanisms (e.g., tin whiskers, plating diffusion, and intermetallics) that would take place regardless of storage conditions
Functional and parametric degradation of microcircuits due to total ionizing dose (TID) often poses serious obstacles to deployment of critical state-of-the-art (SOTA) technologies in NASA missions. Moreover, because device dielectrics in which such degradation occurs vary from one fabrication lot to the next, these effects must be reevaluated on a lot-by-lot basis. Often, the most effective mitigation against TID degradation is the addition of radiation shielding to the electronics box. Unfortunately, shielding materials can add significant amounts of mass to a system, particularly when vulnerable parts require shielding over 4π steradians. One method for reducing mass is to apply spot shielding located only on the critical components that require it. Reduced box- and/or spacecraft-level shielding will necessitate more complex spot shielding to protect the component from the omnidirectional radiation environment
Recent advancements in space technology have resulted in space exploration becoming a rapidly growing field, and the desire for human space exploration is drastically increasing. Previous manned missions include flights to low Earth orbit (LEO), such as to the International Space Station (ISS); however, upcoming flights are planned to go beyond LEO, such as to asteroids and eventually Mars. A major consideration in such missions is that the space environment is significantly different from that of Earth, especially with respect to the radiation environment. This drastic difference results in concerns regarding radiation dose
Wireless charging systems for electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs) employing the resonant magnetic coupling method and using induction coils have been intensively studied in recent years. Since this method requires kW class high power to be transmitted using resonant magnetic coupling in the high frequency range, it is necessary to pay attention to the leakage of the magnetic field generated by the coil current, and to its influence on surrounding objects, particularly human bodies. Noting that acceptable values for human body exposure to electromagnetic fields have previously been issued by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) as guidelines, we have developed a method for predicting product compliance with those guidelines at the basic design development stage. This method calculates the magnetic field generated by the induction coil current and predicts the value of the electric field induced in the human body
The FAA, using its CARI-6 program, provides galactic cosmic radiation dosage rates for any location on the Earth from ground up to 60,000 ft (≈18,300 m). One way to protect astronauts from galactic cosmic radiation (GCR) on a Mars mission is to use material shielding. However, current radiation shielding code does not model shields thicker than about 100 to 200 gm/cm2, and it has been shown that this shield thickness is insufficient to provide protection for a trip to Mars. There is effort underway to extend the code to thicker shields, but there is a lack of experimental data to use to verify the code. The atmosphere represents a very thick and effective radiation shield, and that atmospheric radiation data might be used as a source of verification data
The complexity of spaceflight design requires reliable, fault-tolerant equipment capable of providing real-time dosimetry during a mission, which is not feasible with existing thermoluminescent dosimeter (TLD) technology. Real-time monitoring is important for low-Earth-orbiting spacecraft and interplanetary spaceflight to alert the crew when solar particle events (SPE) increase the particle flux of the spacecraft environment. In this innovation, the personal dosimeter is comprised of a tissue-equivalent scintillator coupled to a solid-state photomultiplier
Of several ideas being pursued by NASA for the reduction of radiation dosage to astronauts, the use of ultra-high-molecular-weight polyethylene (UHMWPE)-based composite materials for both radiation shielding and micrometeorite shielding appears to be particularly appealing. UHMWPE has long been understood to provide superior radiation shielding following encounters with energetic nucleons due to its high hydrogen content. Meanwhile, impacts of micrometeorites with UHMWPE tend to vaporize it, rather than causing spallation of the shield material, which then creates additional potentially damaging micrometeorites. Less widely appreciated is the high specific strength of UHMWPE and UHMWPE fibers, which provide structural integrity to the composite. Amongst thermoplastics, UHMWPE has the highest impact strength and is also highly resistant to abrasion. Despite this highly appealing combination of properties, UHMWPE’s key mechanical properties can be improved by forming composites with
Turbocharger performance maps, which are used in engine simulations, are usually measured on a gas-stand where the temperatures distributions on the turbocharger walls are entirely different from that under real engine operation. This should be taken into account in the simulation of a turbocharged engine. Dissimilar wall temperatures of turbochargers give different air temperature after the compressor and different exhaust gas temperature after the turbine at a same load point. The efficiencies are consequently affected. This can lead to deviations between the simulated and measured outlet temperatures of the turbocharger turbine and compressor. This deviation is larger during a transient load step because the temperatures of turbocharger walls change slowly due to the thermal inertia. Therefore, it is important to predict the temperatures of turbocharger walls and the outlet temperatures of the turbocharger working fluids in a turbocharged engine simulation. In the work described in
BHA and BHT are well-known food preservatives that are excellent radical scavengers. These compounds, attached to single-walled carbon nanotubes (SWNTs), could serve as excellent radical traps. The amino-BHT groups can be associated with SWNTs that have carbolyxic acid groups via acid-base association or via covalent association
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