Research Terms
Keywords
Dls Ftir Spectroscopy Light Scattering Particle Characterization Particle Size Pore Characterization Pore Size Rheology Streaming Potential X-Ray Ct X-Ray Tomography Zeta Potential
This multi-variable reactor facilitates the manufacturing of high-precision, core-shell quantum dots - nanoparticles made from semiconductive materials that display unique optical and electrical properties. Quantum dots have applications in computing, photovoltaic devices (solar panels), light emitting diodes (LEDs) and medical imaging equipment. By modifying or "tuning" the precise size and quality of quantum dots, scientists can control the wavelength (bandgap) of light emitted by LEDs, and can select the properties for various other applications, such as fluorescence-based diagnostics and cell staining in medical imaging. Quantum dots are currently manufactured using batch methods, which under hydrothermal conditions, are time-consuming and subject to batch-to-batch variation in the desired properties. Detailed tuning of quantum dots to precise optical properties can be difficult using existing technology. Researchers at the University of Florida have developed a hydrothermal reactor that offers high-precision tuning of quantum dots for bulk production. The reactor enhances reliability, precision, uniformity and throughput during large-scale quantum dot manufacturing, and could help capture a significant portion of the global quantum dots market, which is expected to reach $670 million by 2015.
Multi-variable reactor for bulk manufacturing of high-precision core-shell quantum dots that are used in medical imaging equipment, LEDs and solar cells
Researchers at the University of Florida have developed a multi-variable reactor that enables large-scale production of precise core-shell quantum dots. The technology uses continuous flow manufacturing, hydrothermal conditions and process control with the ability to tune multiple variables. Control parameters (including reactant stoichiometry, concentration, flow rate, temperature, pressure, illumination, heterogenous nucleation, magnetic, electric and gravitational fields) make it possible to manufacture quantum dots that emit at specific wavelengths with peak emission wavelength selectable to within 0.5 nm. A core-shell comprised of cadmium sulfide (CdS) or other non-active materials can be applied as a final step during the flow manufacturing process. The CdS shell protects and preserves the quantum dot's yield and, in some embodiments, decreases or eliminates toxicity when used in biological applications.
This heat transfer fluid for nuclear reactors consists of colloidal diamonds that will increase the critical heat flux level by 50 percent. Approximately 11 percent of the world’s electricity comes from nuclear energy. A global reassessment of future reliance on fossil fuels has caused an increase in nuclear energy related research and development. Although research into nuclear energy has significantly increased, there are still many concerns that need to be addressed. One major problem with the feasibility of nuclear energy is the lack of an enhanced thermal transfer fluid that offers stability for pressurized water reactors. Nuclear energy needs thermal transfer fluids that will raise the critical heat flux level in order to avoid critical fuel rod failures. Researchers at The University of Florida have developed such a heat transfer fluid in the form of a diamond colloid that will increase the critical heat flux level by 50 percent.
Heat transfer fluid for increased heat flux levels in nuclear reactors
This heat transfer fluid, consisting of colloidal diamonds, will increase the critical heat flux level of pressurized water reactors by 50 percent. A pressurized water reactor comprises a core including fuel assemblies that contain fuel rods filled with fuel pellets thermally coupled to a steam generator, a turbine, and a condenser coupled to a water based cooling system. The water based cooling system comprises a heat transfer fluid of multiple colloidal diamonds. The diamond particles, which can be natural or synthetic, have an average size of 1 nm to 2 microns. The concentration of diamond particles ranges from 0.0001 to 10 percent of the total volume of heat transfer fluid.
These materials, made with nano fluids or metal-filled putties, for instance, minimize scatter that arises most strongly during an X-ray or computed tomography (CT) scan of an object, where the object interfaces with the surrounding air. In dentistry, for instance, scatter occurs from existing fillings and crowns, which can distort X-ray images used in diagnosis. The automotive and aviation industries also use X-ray and CT frequently because imaging can help manufacturers inspect and analyze complex manufactured parts and systems without destroying them. Estimates value the global market for industrial X-ray inspection systems to grow to about $350 million by 2022. While available imaging techniques are useful, scattering artifacts can obscure images, causing misinterpretation. Since X-ray attenuation of a spectrum of X-ray energies is a combination of energy, absorption, Rayleigh scatter, and Compton scatter, tailoring a surface-conforming material will greatly increase edge definition. Some imaging instrument manufacturers provide hardware and software solutions to resolve this issue, but they are often expensive and imperfect.
Researchers at the University of Florida have developed scatter mitigation methods using a variety of materials that improve the fidelity of X-ray images by reducing scattering at either the interior surface of an object, or the exterior surface, as long as there is an open path to the exterior of the sample. These materials mitigate scattering by preferentially absorbing scattered photons, which provides a simple and cost-effective strategy for improving clarity of X-rayed and CT scanned objects.
Application
Materials to reduce scattering artifacts in X-ray and CT scan images
Advantages
In X-ray and CT imaging, the most noticeable scatter artifacts appear at the boundary between the surface of an object and the surrounding air or between high attenuation areas within a scan, such as between two fillings in a 3D scan of a mouth, for example. A major factor in these artifacts is Compton scattering, which includes energy partly absorbed and partly re-emitted as an X-ray. These emit in all directions from a scatter event. If emitted towards the interior, they should eventually completely absorb, but if emitted towards air, they will likely reach the detector. A material tailored to absorb these scattered X-rays placed either within the sample or around it can greatly enhance edge definition, as long as there is minimal change in scan time or noise.
