All-silicon carbide hybrid wireless-wired optics temperature sensor: turbine tests and distributed fiber sensor network design

Highlighted are results from a commercial Siemens rig test of the fabricated all-Single crystal Silicon Carbide (SiC) temperature probe. Robust probe design options are introduced. Introduced is a fiber network-based spatially distributed sensor design suitable for turbines

Experimental studies of an all-silicon carbide hybrid wireless-wired optics temperature sensor for extreme environments in turbines

Shown for the first time is the fabricated all-Single crystal Silicon Carbide (SiC) temperature probe and interface assembly designed for extreme environment temperature sensing in a gas turbine test rig. Preliminary probe test results are described regarding SiC chip temporal response, optical beam stability, and near vacuum sealing

Liquid lens confocal microscopy with advanced signal processing for higher resolution 3D imaging

The paper first highlights the use of multiple electronically controlled optical lenses, specifically, liquid lenses to realize an axial scanning confocal microscope with potentially less aberrations. Next, proposed is a signal processing method for realizing high resolution three dimensional (3-D) optical imaging using diffraction limited low resolution optical signals. Using axial shift-based signal processing via computer based computation algorithm, three sets of high resolution optical data is determined along the axial (or light beam propagation) direction using low resolution axial data. The three sets of low resolution data are generated by illuminating the 3-D object under observation along its three independent and orthogonal look directions (i.e., x, y, and z) or by physically rotating the object by 90 degrees and also flipping the object by 90 degrees. The three sets of high resolution axial data is combined using a unique mathematical function to interpolate a 3-D image of the test object that is of much higher resolution than the diffraction limited direct measurement 3-D resolution. Confocal microscopy or optical coherence tomography (OCT) are example methods to obtain the axial scan data sets. The proposed processing can be applied to any 3-D wave-based 3-D imager including ones using electromagnetic waves and sound (ultrasonic) waves. Initial computer simulations are described to test the robustness of the proposed high resolution signal processing metho

Laser beam characterization using agile digital-analog photonics

Precise knowledge of laser beam parameters is a key requirement in many photonics applications including for lasers and optics used in the transportation industry. This paper reports on a novel motion-free laser beam characterization system using electronically agile digital and analog photonics such as a Digital Micromirror Device (DMD) and an analog variable focal length lens. The proposed system has the capability of measuring all the parameters of a laser beam including minimum waist size, minimum waist location, beam divergence and the beam propagation parameter (M2). Experimental results demonstrate the measurement of the minimum beam waist size and location for a test 633 nm fundamental mode Gaussian laser beam. The system is also applicable for imaging of arbitrary beams including non-laser beams

Wireless temperature sensors using single crystal silicon carbide: an industrial feasibility and design study

Single crystal Silicon Carbide (SiC) chip operations for a proposed wireless temperature sensor are evaluated for various power plant industrial conditions such as soot levels, chemical exposure, and changes in polarization

Noncontact no-moving parts surface height measurement sensor using liquid crystal-based axial scanning confocal optical microscopy

An analog liquid crystal lens-based axial scanning confocal microscope is demonstrated as a 48 &mgr;m continuous range optical height measurement sensor used to characterize a 2.3 &mgr;m height Indium Phosphide twin square optical waveguide chip

Investigation of engineering properties of normal and high strength fly ash based geopolymer and alkali-activated slag concrete compared to ordinary Portland cement concrete

Fly ash-based geopolymer (FAGP) and alkali-activated slag (AAS) concrete are produced by mixing alkaline solutions with aluminosilicate materials. As the FAGP and AAS concrete are free of Portland cement, they have a low carbon footprint and consume low energy during the production process. This paper compares the engineering properties of normal strength and high strength FAGP and AAS concrete with OPC concrete. The engineering properties considered in this study included workability, dry density, ultrasonic pulse velocity (UPV), compressive strength, indirect tensile strength, flexural strength, direct tensile strength, and stress-strain behaviour in compression and direct tension. Microstructural observations using scanning electronic microscopy (SEM) are also presented. It was found that the dry density and UPV of FAGP and AAS concrete were lower than those of OPC concrete of similar compressive strength. The tensile strength of FAGP and AAS concrete was comparable to the tensile strength of OPC concrete when the compressive strength of the concrete was about 35 MPa (normal strength concrete). However, the tensile strength of FAGP and AAS concrete was higher than the tensile strength of OPC concrete when the compressive strength of concrete was about 65 MPa (high strength concrete). The modulus of elasticity of FAGP and AAS concrete in compression and direct tension was lower than the modulus of elasticity of OPC concrete of similar compressive strength. The SEM results indicated that the microstructures of FAGP and AAS concrete were more compact and homogeneous than the microstructures of OPC concrete at 7 days, but less compact and homogeneous than the microstructures of OPC concrete at 28 days for the concrete of similar compressive strength

Experimental studies of an all-silicon carbide hybrid wireless-wired optics temperature sensor for extreme environments in turbines.

Shown for the first time is the fabricated all-Single crystal Silicon Carbide (SiC) temperature probe and interface assembly designed for extreme environment temperature sensing in a gas turbine test rig. Preliminary probe test results are described regarding SiC chip temporal response, optical beam stability, and near vacuum sealing.Shown for the first time is the fabricated all-Single crystal Silicon Carbide (SiC) temperature probe and interface assembly designed for extreme environment temperature sensing in a gas turbine test rig. Preliminary probe test results are described regarding SiC chip temporal response, optical beam stability, and near vacuum sealing

Demonstration of three-dimensional optical imaging using a confocal microscope based on a liquid-crystal electronic lens

Three-dimensional (3-D) imaging is demonstrated using an electronically controlled liquid crystal (LC) optical lens to accomplish a no-moving-parts depth-section scanning in a modified commercial 3-D confocal microscope. Specifically, 3-D views of a standard CDC blood vessel (enclosed in a glass slide) have been obtained using the modified confocal microscope operating at the red 633-nm laser wavelength. The image sizes over a 25-μm axial scan depth were 50×50 μm and 80×80 μm, using 60× and 20× micro-objectives, respectively. The transverse motion step was 0.1 μm for the 60× data and 0.2 μm for the 20× data. As a first-step comparison, image processing of the standard and LC electronic-lens microscope images indicates correlation values between 0.81 and 0.91. The proposed microscopy system within aberration limits has the potential to eliminate the mechanical forces due to sample or objective motion that can distort the original sample structure and lead to imaging errors

Less is More: Facial Landmarks can Recognize a Spontaneous Smile

Smile veracity classification is a task of interpreting social interactions. Broadly, it distinguishes between spontaneous and posed smiles. Previous approaches used hand-engineered features from facial landmarks or considered raw smile videos in an end-to-end manner to perform smile classification tasks. Feature-based methods require intervention from human experts on feature engineering and heavy pre-processing steps. On the contrary, raw smile video inputs fed into end-to-end models bring more automation to the process with the cost of considering many redundant facial features (beyond landmark locations) that are mainly irrelevant to smile veracity classification. It remains unclear to establish discriminative features from landmarks in an end-to-end manner. We present a MeshSmileNet framework, a transformer architecture, to address the above limitations. To eliminate redundant facial features, our landmarks input is extracted from Attention Mesh, a pre-trained landmark detector. Again, to discover discriminative features, we consider the relativity and trajectory of the landmarks. For the relativity, we aggregate facial landmark that conceptually formats a curve at each frame to establish local spatial features. For the trajectory, we estimate the movements of landmark composed features across time by self-attention mechanism, which captures pairwise dependency on the trajectory of the same landmark. This idea allows us to achieve state-of-the-art performances on UVA-NEMO, BBC, MMI Facial Expression, and SPOS datasets