Abstract: An oven rack assembly (1000) includes an oven rack (1008) and a slide system (1018). The slide system (1018) includes slide devices (1020) positioned at opposing sides of the oven rack (1008). A subframe (1040) is positioned below the slide devices (1020). Retention/release devices (1062) are mounted on the slide devices (1020) and are manually operable by a user so as to selectively retain the subframe (1040) in a stationary position or, alternatively, release the subframe (1040) so that the subframe (1040) can be removed from the oven (128?).

Abstract: A method is used to design nuclear reactors using design variables and metric variables. A user specifies ranges for the design variables and target values for the metric variables. A set of design parameter samples are selected. For each sample, the method runs three processes, which compute metric variables to thermal-hydraulics, neutronics, and stress. The method applies a cost function to each sample to compute an aggregate residual of the metric variables compared to the target values. The method trains a machine learning model using the samples and the computed aggregate residuals. The method shrinks the range for each design variable according to correlation between the respective design variable and estimated residuals using the machine learning model. These steps are repeated until a sample having a smallest residual is unchanged for multiple iterations. The method then uses the final machine learning model to assess relative importance of each design variable.

Abstract: Plurality of layers form a nuclear fission reactor structure, each layer having an inner segment body, an intermediate segment body, and an outer segment body (each segment body separated by an interface). The layers include a plurality of cladding arms having involute curve shapes that spirally radiate outward from a radially inner end to a radially outer end. Chambers in the involute curve shaped cladding arm contain fuel compositions (and/or other materials such as moderators and poisons). The design of the involute curve shaped cladding arms and the composition of the materials conform to neutronic and thermal management requirements for the nuclear fission reactor and are of sufficiently common design and/or have sufficiently few variations as to reduce manufacturing complexity and manufacturing variability.

Abstract: Methods to in-situ monitor production of additive manufacturing products collects images from the deposition process on a layer-by-layer basis, including a void image of the pattern left in a slurry layer after deposition of a layer and a displacement image formed by immersing the just-deposited layer in a renewed slurry layer. Image properties of the void image and displacement image are corrected and then compared to a binary expected image from a computer generated model to identify defects in the just-deposited layer on a layer-by-layer basis. Additional methods use the output from the comparison to form a 3D model corresponding to at least a portion of the additive manufacturing product. Components to control the additive manufacturing operation based on digital model data and to in-situ monitor successive layers for manufacturing defects can be embodied in a computer system or computer-aided machine, such as a computer controlled additive manufacturing machine.

Abstract: A method designs nuclear reactors using design variables and metric variables. A user specifies ranges for the design variables and threshold values for the metric variables and selects design parameter samples. For each sample, the method runs three processes, which compute metric variables for thermal-hydraulics, neutronics, and stress. The method applies a cost function to compute an aggregate residual of the metric variables compared to the threshold values. The method deploys optimization methods, either training a machine learning model using the samples and computed aggregate residuals, or using genetic algorithms, simulated annealing, or differential evolution. When using Bayesian optimization, the method shrinks the range for each design variable according to correlation between the respective design variable and estimated residuals using the machine learning model. These steps are repeated until a sample having a smallest residual is unchanged for multiple iterations.

Abstract: Fission reactor has a cladding encasing a heat generating source including a fissionable nuclear fuel composition. The heat generating source is offset from the surface of the cladding and molten metal is located within the void space formed by the offset. As a liquid, the molten metal will flow and occupy any contiguous network of void space within the fuel cavity and provides thermal transfer contact between the heat generating source and the cladding. The cladding separates the heat generating source and the molten metal from the primary coolant volume.

Abstract: A mobile modular reactor, in particular, a graphite-moderated fission reactor, has an active core region and at least a portion of control region(s) that are located within an interior volume of a pressure vessel. Flow annulus features located in the flow annulus between an outer surface of the control rod/fuel rod and an inner surface of the cladding of the channel in which the rod is located stabilizes the flow annulus and maintains a reliable concentricity between the inner and outer claddings that envelope the flow annulus. Flow annulus features are equally circumferentially spaced at longitudinally separated locations and the flow annulus features at successive, longitudinally separated locations are rotationally offset relative to each other. For purposes of transportability, the pressure vessel is sized for mobile transport using a ship, train or truck, for example, by fitting within a shipping container.

Abstract: Nuclear propulsion fission reactor structure has an active core region including fuel element structures, a reflector with rotatable neutron absorber structures (such as drum absorbers), and a core former conformal mating the outer surface of the fuel element structures to the reflector. Fuel element structures are arranged abutting nearest neighbor fuel element structures in a tri-pitch design. Cladding bodies defining coolant channels are inserted into and joined to lower and upper core plates to from a continuous structure that is a first portion of the containment structure. The nuclear propulsion fission reactor structure can be incorporated into a nuclear thermal propulsion engine for propulsion applications, such as space propulsion.

Abstract: Additive manufacturing methods use a surrogate slurry to iteratively develop an additive manufacturing protocol and then substitutes a final slurry composition to then additively manufacture a final component using the developed additive manufacturing protocol. In the nuclear reactor component context, the final slurry composition is a nuclear fuel slurry having a composition: 30-45 vol. % monomer resin, 30-70 vol. % plurality of particles of uranium-containing material, >0-7 vol. % dispersant, photoactivated dye, photoabsorber, photoinitiator, and 0-18 vol. % (as a balance) diluent. The surrogate slurry has a similar composition, but a plurality of surrogate particles selected to represent a uranium-containing material are substituted for the particles of uranium-containing material. The method provides a means for in-situ monitoring of characteristics of the final component during manufacture as well as in-situ volumetric inspection.

Abstract: Pre-ceramic particle solutions can prepared by a Coordinated-PDC process, a Direct-PDC process or a Coordinated-Direct-PDC process. The pre-ceramic particle solution includes a polymer selected from the group consisting of (i) an organic polymer including a metal or metalloid cation, (ii) a first organometallic polymer and (iii) a second organometallic polymer including a metal or metalloid cation different from a metal in the second organometallic polymer, a plurality of particles selected from the group consisting of (a) a ceramic fuel particle and (b) a moderator particle, a dispersant, and a polymerization initiator. The pre-ceramic particle solution can be supplied to an additive manufacturing process, such as digital light projection, and made into a structure (which is pre-ceramic particle green body) that can then be debinded to form a polymer-derived ceramic sintered body. In some embodiments, the polymer-derived ceramic sintered body is a component or structure for fission reactors.

Abstract: Embodiments disclosed herein relate to cryptology, and more particularly to secure sharing of data objects stored in the at least one cloud device between two user devices using the PRE. Embodiments herein disclose methods and systems for enabling a first user device to subscribe with a key server for uploading encrypted data object to at least one cloud device using the PRE. Embodiments herein disclose methods and systems for allowing the first user device to share the encrypted data object stored in the at least one cloud device with a second user through the key server using the PRE.

Abstract: A structural insulated building unit is provided for constructing a building. The structural insulated building unit includes an insulating core, first and second cementitious panels, and a connecting portion. The insulating core is defined by multiple sides and opposing first and second faces. The first and second cementitious panels are coupled to the first and second faces of the insulating core. The connecting portion is provided on one of the sides of the insulating core, and aligns the structural insulated building unit with an adjacent structural insulated building unit having a complementary connecting portion when constructing a building.

Abstract: A wearable device utilizing flexible electronics is disclosed. The wearable device may comprise a flexible matrix material and may include sensors for measuring biometric measurements of an individual, an accelerometer for measuring an acceleration of a body part to which the wearable device is attached, a wireless transmitter, a flexible power source, and a microcontroller. During an activity, the microcontroller may receive signals from the sensors including the biometric measurements, and signals from the accelerometer including acceleration and force measurements associated with the individual. The microcontroller may convert the signals into digital signals and transmit the signals to a computing device for analysis. The computing device may analyze the digital signals to determine a performance metric for the individual. The performance metric may be compared to baseline data for the individual to determine a fatigue level, injury risk, or an adjustment to be made by the individual during the activity.

Abstract: In some aspects, the present invention embodies both the method and apparatus for converting a pattern of irradiation to a visible image. An embodiment of the present invention provides an array of micro-electro-mechanical sensors with each sensor includes a deflectable micro-cantilever, responsive to absorbed incident radiation and to an applied repulsive electrostatic field. Associated circuitry senses a change in an output signal of the sensor as it responds to incident radiation incident upon the cantilever and provides a biasing force to deflect the cantilever and maintain the detector output signal at a desirable level. The biasing element may be a piezoelectric element, a heater or a pair of electrodes and the corresponding biasing stimulus may be stress (expansion), heat, or electrostatic change. The stimulus compensates for the effect of the infrared radiation and maintains the chosen detector output level at the same level.

Abstract: Described are various embodiments of a dual optical modulator, system and method. In one embodiment, an optical modulator modulates an input optical signal having a designated optical frequency. The modulator comprises first and second tunable modulators operable around the optical frequency and operatively disposed between a bus waveguide path and an opposed waveguide path. The modulator further comprises a relative optical phase-shifter optically coupled between the tunable modulators so to impart a relative optical phase shift between the bus waveguide path and the opposed waveguide path. The tunable modulators are respectively driveable to modulate a respective resonance thereof in complimentary directions relative to the optical frequency and thereby resonantly redirect a selectable portion of the input optical signal along the opposed waveguide path such that the relative optical phase shift is imparted thereto for output.

Abstract: A temperature-controlled photodetector sub-system is described. The temperature control element allows the operation of the photodetector at a desired temperature. The temperature control element can be a heater or a cooler. In some cases, the photodetector is a germanium photodetector. In some cases a temperature measuring device is provided. In some cases, a control circuit is used to control the temperature of the germanium photodetector within a temperature range, or at a temperature of interest. An advantage provided by the apparatus described is the operation of the photodetector so that the responsivity of the germanium detector can be held at essentially a constant value.

Abstract: A heat sink for a semiconductor chip device includes cavities in a lower surface thereof for receiving electrical components on a top surface of the semiconductor chip, and a pedestal extending through an opening in the semiconductor chip for contacting electrical components on a bottom surface of the semiconductor chip. A lid may also be provided on the bottom surface of the semiconductor chip for protecting the electrical components and for heat sinking the electrical components to an adjacent device or printed circuit board.

Abstract: An optical modulator apparatus may include a plurality of segment drivers, each segment driver having a unique offset voltage and driving but a portion or a segment of an electro-optical modulator. A modulating electrical signal may be applied to the segment drivers via a plurality of electrical delays. Parameters of the segment drivers may be selected so as to approximate a pre-defined transfer function, which may include a linear or a non-linear transfer function.

Abstract: An optical device that includes means for thermal stabilization and control is described. The optical device can be a ring resonator, or another device that requires accurate control of the phase of the optical signal. In an example involving an optical resonator, a thermal stabilization system includes a temperature sensor, a control circuit, and a heater local to the resonator. The temperature sensor can be a bandgap temperature sensor formed of a pair of matched p/n junctions biased in operation at different junction currents.

Abstract: A photonic interface for an electronic circuit is disclosed. The photonic interface includes a photonic integrated circuit having a modulator and a photodetector, and an optical fiber or fibers for optical communication with another optical circuit. A modulator driver chip may be mounted directly on the photonic integrated circuit. The optical fibers may be placed in v-grooves of a fiber support, which may include at least one lithographically defined alignment feature for optical alignment to the silicon photonic circuit.