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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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At least 1,333 records · Page 74
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Medium-Voltage Testbed for Comparing Advanced Power Line Sensors vs. Measurement Transformers with Electrical Grid Events

Electrical utilities have relied upon potential transformers (PTs) and current transformers (CTs) for very accurate metering and to provide reliable signals for protective relays. Less expensive alternative sensing technologies offer the possibility of wider deployment, particularly in grids that employ distributed energy resources. In this work, the performance of an advanced medi-um-voltage sensor is compared with a reference PT and CT and experimentally evaluated for different power grid scenarios on an advanced outdoor power line sensor testbed at the US De-partment of Energy’s Oak Ridge National Laboratory. The sensor is based on a capacitive divider for voltage monitoring and a Rogowski coil with integrator for current monitoring. The advanced outdoor power line sensor testbed has a real-time simulator that was used to generate transient scenarios (e.g., electrical faults, capacitor bank operation, service restoration), while the analog signals were recorded by the same high resolution power meter. The behavior of analog signals, harmonic components, total harmonic distortion, and crest factors were assessed for this power line sensor compared with the reference PT/CT, because of the absence for testing standards for advanced outdoor power line sensors.

Piesciorovsky, Emilio↗
DOE OSTI2021

Distributed Acoustic Sensing Based on Coherent Microwave Photonics Interferometry

A microwave photonics method has been developed for measuring distributed acoustic signals. This method uses microwave-modulated low coherence light as a probe to interrogate distributed in-fiber interferometers, which are used to measure acoustic-induced strain. By sweeping the microwave frequency at a constant rate, the acoustic signals are encoded into the complex microwave spectrum. The microwave spectrum is transformed into the joint time–frequency domain and further processed to obtain the distributed acoustic signals. The method is first evaluated using an intrinsic Fabry Perot interferometer (IFPI). Acoustic signals of frequency up to 15.6 kHz were detected. The method was further demonstrated using an array of in-fiber weak reflectors and an external Michelson interferometer. Two piezoceramic cylinders (PCCs) driven at frequencies of 1700 Hz and 3430 Hz were used as acoustic sources. The experiment results show that the sensing system can locate multiple acoustic sources. The system resolves 20 nε when the spatial resolution is 5 cm. The recovered acoustic signals match the excitation signals in frequency, amplitude, and phase, indicating an excellent potential for distributed acoustic sensing (DAS).

47 OTHER INSTRUMENTATION↗
DOE OSTI2023

Alignments between Galaxies and the Cosmic Web at z ~ 1–2 in the IllustrisTNG Simulations

Galaxy formation theories predict that galaxy shapes and angular momenta have nonrandom alignments with the cosmic web. This leads to so-called intrinsic alignment between pairs of galaxies, which is important to quantify as a nuisance parameter for weak lensing. We study galaxy–cosmic web alignment in the IllustrisTNG suite of hydrodynamical simulations at redshifts 1 and 2, finding that alignment trends are consistent with previous studies. However, we find that the magnitude of the spin alignment signal is ~2.4× weaker than seen in previous studies of the Horizon-AGN simulation, suggesting that this signal may have a significant dependence on subgrid physics. Based on IllustrisTNG, we then construct mock observational spectroscopic surveys that can probe shape–cosmic web alignment at z ~ 1–2, modeled on the low-z galaxy redshift and IGM tomography surveys on the upcoming Subaru Prime Focus Spectrograph Galaxy Evolution (PFS GE) survey. However, even over box sizes of L = 205 h -1 Mpc, we find that global anisotropies induce a sample variance in the 2D projected alignment signal that depend on the projected direction; this induces significant errors in the observed alignment. We predict a 5.3σ detection of IllustrisTNG's shape alignment signal at z ~ 1 from Subaru PFS GE, although a detection would be challenging at z ~ 2. However, a rough rescaling of the relative alignment signal strengths between the TNG and Horizon-AGN simulations suggests that PFS GE should be able to more easily constrain the latter's stronger signal.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2020

Systems and methods for detection of occupancy using radio waves

Systems and methods are disclosed for detecting a presence of a person in an area of coverage using radar. A transmitter can transmit radio signals in a first direction in an area of coverage defined by a wall and a floor. A receiver can receive the transmitted radio signals reflected back from the area of coverage. A signal conditioning circuit can process the received radio signals. One or more hardware processors can be programmed to analyze the processed radio signals and detect a presence of a person in the area of coverage based on the analysis. The analysis of the processed signals can be performed in both time and frequency domain. In addition to radar, an input from an infrared sensor can also be used in conjunction with radar based detection.

42 ENGINEERING↗
DOE OSTI2020

Virtual synchronous generator system and method with virtual inertia control

A virtual synchronous generator device disclosed. The device includes an inverter and inverter controller having a power control portion, a power reserve portion, a power point tracking control portion, and a virtual inertia control portion. The power reserve portion determines an amount of power to be reserved and sends a signal, indicative of the determined amount of power to the power point tracking controller. The power point tracking controller determines a power point that is less than a MPP, and provides a signal to the power control portion indicative of the determined power point. The inertia control portion determines a virtual inertia and provides a signal indicative of the virtual inertia to the power control portion. The power control portion provides a power control signal to the inverter based on the power point tracking signal and the inertia command signal.

42 ENGINEERING↗
DOE OSTI2020

Performance CMOS voltage level-up shifter circuit topology using pre-drive pull-up transistors

In a first example a voltage level-shifting device includes a level-shifting stage circuit. The level-shifting stage circuit includes a first level-shifting inverter circuit to invert a buffered input signal to drive a first internal node, a second level-shifting inverter circuit to invert a buffered inverted input signal to drive a second internal node, a first pre-drive circuit that receives the buffered inverted input signal, and drives the second internal node based on the state of the buffered inverted input signal, and a second pre-drive circuit that receives the buffered input signal, and drives the first internal node based on the state of the buffered input signal.

Armstrong, Paul R.↗
DOE OSTI2021

Integrated circuit authentication from a die material measurement

The various technologies presented herein relate to measuring a signal generated by a die-based test circuit incorporated into an IC and utilizing the measured signal to authenticate the IC. The signal can be based upon a sensor response generated by the test circuit fabricated into the die, wherein the sensor response is based upon a property of the die material. The signal can be compared with a reference value obtained from one or more test circuit(s) respectively located on one or more reference dies, wherein the reference dies are respectively cut from different wafers, and the location at which the reference dies were cut is known. If the measured signal matches the reference value, the die is deemed to be from the same cut location as the dies from which the reference value was obtained. If the measured signal does not match the reference value, the die is not authenticated.

Zortman, William A.↗
DOE OSTI2021

Fiber laser microphones with graphene diaphragms

An acoustic sensor comprises a sensing head comprising an optical fiber having a tip. A graphene diaphragm is disposed on the tip and is configured to vibrate in response to an acoustic signal. A fiber laser is optically coupled to the sensing head. The fiber laser comprises a first set of fiber Bragg gratings and a second set of fiber Bragg gratings. A gap is present between the first set and the second set of fiber Bragg gratings. The fiber laser is configured to generate a sensing optical signal having a first intensity in response to an excitation optical signal, the sensing optical signal impinging on the graphene diaphragm such that a feedback optical signal is reflected from the graphene diaphragm towards the fiber laser and has and has a second intensity modulated by the vibration of the graphene diaphragm that corresponds to the acoustic signal.

Liao, Shaolin↗
DOE OSTI2021

Inductive circuit sensor system and method

An inductive circuit sensor system and method for monitoring an electromagnetic signal path through a circuit is shown. A protected element or door is movably positionable adjacent to the stationary element or frame in a monitored position. A conductive sensor pattern element is connected to a pair of inductive coils. The pattern element is a conductive wire traversing a predetermined cross-section of the door. The frame has a transmitting coil in communication with a microcontroller. The transmitting coil is coupled with the first coil and a receiving coil is coupled with the second coil. The transmitting coil receives a signal from the microcontroller and couples the signal to the pattern element. The signal is in communication with a receiving port on the microcontroller. The microcontroller is programmed to compare the signal from the transmit port with the signal at the receiving port.

Neidigk, Stephen↗
DOE OSTI2021

Optical encoder devices and systems

Devices, systems and methods for encoding information using optical components are described. Information associated with a first optical signal (e.g., an optical pump) is encoded onto the phase of a second optical signal (e.g., an optical probe) using cross phase modulation (XPM) in a non-linear optical medium. The optical signals are multiplexed together into the nonlinear optical medium. The probe experiences a modified index of refraction as it propagates through the medium and thus accumulates a phase change proportional to the intensity of the pump. The disclosed devices can be incorporated into larger components and systems for various applications such as scientific diagnostics, radar, remote sensing, wireless communications, and quantum computing that can benefit from encoding and generation of low noise, high resolution signals. Examples of the encoded information includes intrinsic noise from the optical source, or others signals of interest, such as electrical, optical, X-ray, or high-energy particle signals.

Buckley, Brandon Walter↗
DOE OSTI2022

Timing measurement apparatus

Methods, devices and systems for providing accurate measurements of timing errors using optical techniques are described. An example timing measurement device includes an optical hybrid that receives two optical pulse trains and produces two or more phase shifted optical outputs. The timing measurement device further includes two or more optical filters that receive the outputs of the optical hybrid to produce multiple pulse signals with distinctive frequency bands. The device also includes one or more photodetectors and analog-to-digital converters to receive to produce electrical signals in the digital domain corresponding to the optical outputs of the hybrid. A timing error associated with the optical pulse trains can be determined using the electrical signals in digital domain based on a computed phase difference between a first frequency band signal and a second frequency band signal and a computed frequency difference between the first frequency band signal and the second frequency band.

DeVore, Peter Thomas Setsuda↗
DOE OSTI2022

Three-phase differential mode converter

A system for charging a battery includes three sub-modules, each receiving a respective phase of a three-phase alternating current (AC) signal. The three sub-modules cooperate to transform the respective phases of the three-phase AC signal to a direct current (DC) signal by passing the respective phases of the three-phase AC signal through a respective semiconductor device configured to discontinuously modulate the respective phase of the three-phase AC signal to convert it to a DC signal provided to the battery to charge the battery.

Mazumder, Sudip K.↗
DOE OSTI2023

Optical encoder devices and systems

Devices, systems and methods for encoding information using optical components are described. Information associated with a first optical signal (e.g., an optical pump) is encoded onto the phase of a second optical signal (e.g., an optical probe) using cross phase modulation (XPM) in a non-linear optical medium. The optical signals are multiplexed together into the nonlinear optical medium. The probe experiences a modified index of refraction as it propagates through the medium and thus accumulates a phase change proportional to the intensity of the pump. The disclosed devices can be incorporated into larger components and systems for various applications such as scientific diagnostics, radar, remote sensing, wireless communications, and quantum computing that can benefit from encoding and generation of low noise, high resolution signals. Examples of the encoded information includes intrinsic noise from the optical source, or others signals of interest, such as electrical, optical, X-ray, or high-energy particle signals.

Buckley, Brandon Walter↗
DOE OSTI2023

System and method for microwave volumetric additive manufacturing

The present disclosure relates to a volumetric additive manufacturing system for forming a structure from a volume of resin using microwave energy. The system makes use of an electronic controller and at least one beam forming algorithm accessible by the electronic controller for generating information relating to an amplitude and a time delay for forming a microwave signal, where the microwave signal will be used in irradiating a build volume, and where the build volume is formed by the volume of resin. A microwave signal generating subsystem is included which is responsive to the information generated by the beam forming algorithm, and which generates a microwave signal using the amplitude and the time delay determined by the beam forming algorithm. An antenna is used to receive the microwave signal and project the microwave signal as a microwave beam, in accordance with the amplitude and time delay, into the build volume to form the structure.

Mukherjee, Saptarshi↗
DOE OSTI2024

Search for 2p2h Interactions in the NOνA Near Detector

The physics of 2p2h interactions and their contribution to the NO$\nu$A near detector data are not fully understood. This study attempts to shed some light on these interactions and the accuracy of the models used to simulate them through a search for a specific 2p2h interaction in the NO$\nu$A near detector. By performing an event selection algorithm based on particle identifier algorithms run over reconstructed data, a signal region is created to minimize the background while maximizing the number of 2p2h events where a muon neutrino interacts with a neutron and a proton coupled by a meson exchange current and produces two protons and one muon. In the signal region, separation is found between the signal events and the background in plots of the angles between the protons and the muon. Although a full statistical analysis is not completed in this study, comparing the angle plots for simulation and data shows that the model used to simulate the events reasonably approximates reality and that the near detector data likely includes signal events. Signal events are also identified in event displays, further indicating that there is some contribution of the signal to the overall NO$\nu$A near detector data.

Gable, Kyle↗
DOE OSTI2024

System and method for in situ volumetric sensing of 3D cure state of resin being used in an additive manufacturing system

An in situ cure monitoring control system for use with a volumetric three dimensional (3D) printing system, wherein the volumetric 3D system includes a container defining a build volume, the container includes a photocurable resist used for making a 3D part, and the resist is responsive to an optical curing beam from a light source, which is controlled by a controller, and which is passed through the resist. The cure monitoring control system includes an optical signal source which generates optical signals having a wavelength selected in relation to a characteristic of the resist, and directed to pass through the build volume. A detector detects the optical signals and generates output signals in accordance therewith. Software monitors the output signals and uses the output signals to modify the curing beam to help optimize curing of the resist.

Panas, Robert Matthew↗
DOE OSTI2024

Timing measurement apparatus

Methods, devices and systems for providing accurate measurements of timing errors using optical techniques are described. An example timing measurement device includes an optical hybrid that receives two optical pulse trains and produces two or more phase shifted optical outputs. The timing measurement device further includes two or more optical filters that receive the outputs of the optical hybrid to produce multiple pulse signals with distinctive frequency bands. The device also includes one or more photodetectors and analog-to-digital converters to receive to produce electrical signals in the digital domain corresponding to the optical outputs of the hybrid. A timing error associated with the optical pulse trains can be determined using the electrical signals in digital domain based on a computed phase difference between a first frequency band signal and a second frequency band signal and a computed frequency difference between the first frequency band signal and the second frequency band.

DeVore, Peter Thomas Setsuda↗
DOE OSTI2024

Systems and methods for flexible, high-density opto-electronic arrays

An opto-electronic probe system is disclosed. The probe system has a probe element including at least one microelectrode, with the probe element being implantable in tissue of an anatomy to receive electrical signals generated within the anatomy. A subsystem is included for at least one of generating excitation signals to be used in stimulating the anatomy, or for receiving electrical signals received from the anatomy. An interface portion is included which is in communication with the subsystem for communicating at least one of electrical signals or optical signals indicative of the electrical signals received by the microelectrode.

Patra, Susant↗