Browse Topic: Radiation
Researchers at the National Institute of Standards and Technology (NIST) and colleagues have developed standards and calibrations for optical microscopes that allow quantum dots to be aligned with the center of a photonic component to within an error of 10 to 20 nanometers (about one-thousandth the thickness of a sheet of paper). Such alignment is critical for chip-scale devices that employ the radiation emitted by quantum dots to store and transmit quantum information
Advances in optical sensors and imaging technologies are ever more rapidly assimilated into how humans interact, understand themselves, and explore the world around them. The scope of inquiry for optical devices is broad and they enable technologies within, such as implanted transdermal bioMEMS devices, and beyond, or as space-flight surveyors deployed as near and deep space instruments. Central to the functionality of modern optical devices, ultra-narrow bandpass (UNBP) thin-film optical filters enable discrimination of sub-nanometer bands inside broad spectra. These filters, pioneered as NIR DWDM filters for the telecommunications industry, are now essential in extracting meaningful signal from imaging and sensing devices operating anywhere between the deep ultraviolet and the mid infra-red bands
Sensor packaging, particularly for microelectromechanical systems (MEMS), is a critical aspect of modern electronics. MEMS developers have demonstrated a variety of innovative microsensors for almost every possible sensing modality including temperature, pressure, inertial forces, chemical species, magnetic fields, radiation, etc. While MEMS sensors are revolutionizing various industries with their precision and miniaturization, they can present unique product development challenges and risks during design, development, and manufacturing
Northwestern University researchers have developed new devices based on a low-cost material to aid in the detection and identification of radioactive isotopes. Using cesium lead bromide in the form of perovskite crystals, the research team found that they were able to create highly efficient detectors in both small, portable devices for field researchers and in very large detectors. The results are more than a decade in the making
Focused on the permanent magnet synchronous motor (PMSM) used in electric, this paper proposes an online insulation testing method based on voltage injection under high-temperature and high-humidity conditions. The effect of constant humidity and temperature on the insulation performance has been also studied. Firstly, the high-voltage insulation structure and principle of PMSM are analyzed, while an electrical insulation testing method considered constant humidity and temperature is proposed. Finally, a temperature and humidity experimental cycling test is carried out on a certain prototype PMSM, taking heat conduction and radiation models, water vapor, and partial discharge into account. The results show that the electrical insulation performance of the motor under constant humidity and temperature operation environment exhibits a decreasing trend. This study can provide theoretical and practical references for the reliable durability design of PMSM
An international team of scientists reports a novel technique for a high-brightness coherent and few-cycle duration source spanning seven optical octaves from the UV to the THz
Recent experiments by a team from the West Virginia University focused on how a weightless microgravity environment affects 3D printing using titania foam, a material with potential applications ranging from UV blocking to water purification. ACS Applied Materials and Interfaces published their findings
Imagine being able to snap a picture of extremely fast events on the order of a picosecond. Compressed ultrafast photography (CUP) captures the entire process in real time and unparalleled resolution with just one click. The spatial and temporal information is first compressed into an image and then, using a reconstruction algorithm, it is converted into a video
Most space satellites are powered by photovoltaic cells that convert sunlight to electricity. Exposure to certain orbit radiation can damage the devices, degrading their performance and limiting their lifetime. University of Cambridge scientists have proposed a radiation-tolerant photovoltaic cell design that features an ultrathin layer of light-absorbing material
As a new method to examine the extremely unsteady and spatially varying wall heat transfer phenomena on diesel engine combustion chamber wall, high-speed imaging of infrared thermal radiation from the chromium coated window surface impinged by a diesel spray flame has been conducted in a constant volume combustion chamber. The infrared radiation from a back surface of the chromium layer was successfully visualized at 10kHz frame rate and 128 × 128 pixel resolution through the window. The distributions of infrared radiation, temperature and heat flux exhibited coherent and streaky structure with radial stripes extending and waving from a stagnation point likely reflecting the near-wall turbulent structure in a wall impinging diesel flame. The experiments were conducted with various parameters such as fuel injection pressure, ambient gas oxygen concentration, wall impinging distance, wall surface roughness and wall materials. Imaging velocimetry analysis was applied to the movement of
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
Space Dynamics Laboratory Utah State University North Logan, UT 435-713-3400
A wavelength of visible light is about 1,000 times larger than an electron, so the way the two affect each other is limited by that disparity. Now, researchers have come up with a way to make much stronger interactions between photons and electrons possible — in the process producing a hundred-fold increase in the emission of light from a phenomenon called Smith-Purcell radiation
To empirically estimate the radiation of sound sources, a measurement with microphone arrays is required. These are used to solve an inverse problem that provides the radiation characteristics of the source. The resolution of this estimation is a function of the number of microphones used and their position due to spatial aliasing. To improve the radiation resolution for the same number of microphones compared to standard methods (Ridge and Lasso), a method based on normalizing flows is proposed that uses neural networks to learn empirical priors from the radiation data. The method then uses these learned priors to regularize the inverse source identification problem. The effects of different microphone arrays on the accuracy of the method is simulated in order to verify how much additional resolution can be obtained with the additional prior information
Radiation shielding for space as well as some terrestrial applications is challenging due to the wide variety and energy ranges of radiation particles. NASA Ames has developed a novel technology that provides a new process for designing and accurately tuning radiation shields to possess the specific characteristics required for each application before testing, reducing the need for iterative radiation beam testing throughout the development process
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
Astronauts who spend six months in space are exposed to roughly the same amount of radiation as 1,000 chest X-rays. Having multiple kinds of radiation bombard their bodies puts them at risk for cancer, central nervous system damage, bone loss, and some cardiovascular diseases. NASA funded research into a new method for measuring radiation damage to humans. Now, 19 years later, that fundamental science supports a diagnostic test to improve cancer treatment on Earth, called the OncoMate MSI Dx Analysis System
UCSD San Diego, CA
This test method specifies the operating conditions for a fluorescent ultraviolet (UV) and condensation apparatus used for the accelerated exposure of various automotive exterior components
Rice University photonics researchers have created a potentially disruptive technology for the ultraviolet optics market
The GPS Radio Occultation and Ultraviolet — Colocated (GROUP-C) experiment was originally conceived in 2010 as a CubeSat mission, combining a compact GPS occultation receiver and high-sensitivity far-ultraviolet (FUV) photometer experiment to be flown as a Space Test Program experiment. The concept was to incorporate a commercial off-the-shelf GPS receiver and a small second-generation FUV photometer to replicate the space weather portion of the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC/FORMOSAT-3) mission at lower cost. In the same timeframe, the Air Force Space and Missile System Center initiated the Space Environment NanoSatellite Experiment (SENSE) to demonstrate several CubeSat technologies for space environment sensing, which included the Compact Tiny Ionospheric Photometer (CTIP) and the Compact Total Electron Content Sensor (CTECS
Engineers have created a deep-ultraviolet (UV) laser using semiconductor materials that show great promise for improving the use of UV light for sterilizing medical tools, among other applications. The aluminum gallium nitride-based device is capable of emitting a deep-UV laser at sought-after wavelengths and modal line widths. The team used molecular beam epitaxy, a crystal growth technique, to grow a high-quality crystal of aluminum nitride
Titan, Saturn’s largest moon and the only celestial body which is found to have a landmass composed of liquid hydrocarbons. Nitrogen - The building block of all life that exists on earth is found to be abundant in Titan’s atmosphere of up to 97%. Aerobots provide a great platform for exploring a celestial body with an atmosphere such as Titan. They have modest power requirements, longer mission duration, and can cover a longer distance in a shorter time. They are powered by a Radioisotope Thermoelectric Generator for optimal mission life. Aerobot’s altitude can be altered by varying the temperature of the air inside the balloon and yaw can be controlled using a Reaction Wheel and a motor-driven propeller for forwarding thrust. The proposed Aerobot will be equipped with four miniature deployable fixed weather stations that can be dropped from the aerobot to Titan's surface. They can be deployed at diverse locations such as the equator and Polar Regions to deeply explore the Titan’s
Where the ability to detect mid-wave infrared (MWIR) radiation is mission critical, readiness and the importance of long, maintenance-free infrared (IR) system operation is vital. In turn, cooled MWIR camera modules must be designed, tested, and manufactured to meet rigorous environmental and reliability requirements. This includes military temperature ranges and high shock and vibration levels. Cooled MWIR camera reliability and operational lifetime are typically determined by the operation and lifetime of the cryo-cooler within such systems
The thermal behavior of wires within the electrical distribution system (EDS) has a strong impact on the conductor cross section, the type of insulation, the derating, and the fusing system, and therefore on weight, cost, and reliability. Consequently, significant efforts have been made to develop sound static and dynamic thermal models for single wires and wire bundles. However, these models are based on the simplifying assumption that the object is completely surrounded by air, where, with the exception of free convection, airflow can be neglected, and where no interaction with other objects is considered. The approach presented in this paper takes into account the actual environment and routing within a vehicle, where some objects such as metal sheets can be considered as heat sinks and other objects, e.g. a motor block, as heat sources. For this reason, measurements were performed using an experimental set-up that allows any desired positioning and alignment of the DuT (device
This SAE Aerospace Standard (AS) specifies the minimum design and performance criteria and testing methods of fire containment covers (FCCs) used either: a In those cargo compartments of civil transport aircraft where they constitute one means of complying with applicable airworthiness regulations, or b On a voluntary basis, when deemed appropriate by operators to improve fire protection in aircraft cargo compartments where airworthiness regulations do not mandate their use
Renesas Electronics Corporation Milpitas, CA 408-432-8888
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