Browse Topic: Spectroscopy

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Wearables: Gold Sensor Performs On-Body Chemical AnalysisTBMG-4695611/01/2022
Design and Computational Investigations of Aerobot for Titan with maneuverability using momentum wheel and propeller equipped with droppable weather stations 2022-26-119105/26/2022
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 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 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 climate
Raja, Manoj Kumar, Sivasankaran, Abinash Nataraj, Saravana Mohan, Haribalan, Thangavel, Sabari, R, Vijayanandh, Gnanasekaran, Raj Kumar
The Effect of Temperature on the Molecular Compositions of External and Internal Gasoline Direct Injection Deposits2021-01-118809/21/2021
The increased severity and prevalence of insoluble deposits formed on fuel injectors in gasoline direct injection (GDI) engines precipitates negative environmental, economic and healthcare impacts. A necessary step in mitigating deposits is to unravel the molecular compositions of these complex layered materials. But very little molecular data has been acquired. Mass spectrometry shows promise but most techniques require the use of solvents, making them unsuited for analyzing insoluble deposits. Here, we apply the high mass-resolving power and in-situ analysis capabilities of 3D OrbitrapTM secondary ion mass spectrometry (3D OrbiSIMS) to characterize deposits formed on the external tip and internal needle from a GDI injector. This is the first application of the technique to study internal GDI deposits. Polycyclic aromatic hydrocarbons (PAHs) are present up to higher maximum masses in the external deposit. Lubricating oil derived sulfonates are more intense in the internal deposit
Edney, Max K., Smith, Emily F., Wilmot, Edward, Reid, Jacqueline, Barker, Jim, Alexander, Morgan R., Snape, Colin E., Scurr, David J.
Formaldehydes Measurement Using Laser Spectroscopic Gas Analyzer2021-01-060404/06/2021
The use of alternative fuels, especially oxygenated fuels in automobile engines, has been increasing owing to the stringent global fuel economy and emission regulations. As a result, it is concerned that the emissions of alcohols and aldehydes have increased significantly. Aldehydes, formaldehyde (HCHO) in particular, are non-criteria pollutants that are acutely toxic and/or carcinogenic. Several reports have associated HCHO with potential lung and airway cancers. Therefore, emission regulations for these compounds have already been implemented in several areas worldwide. The conventional measurement (impinger, etc.) methods for HCHO possess advantages and disadvantages. HCHO can be measured with high sensitivity if measured in a batch. However, in real-time measurements, low concentration measurements are challenging. To overcome this challenge, a real-time HCHO analyzer for low concentration measurement of 0.1 ppm resolution in real time of 10Hz was developed in this study based on
Hara, Kenji, Shibuya, Kyoji, Nagura, Naoki, Hanada, Takaaki, Tsurumi, Kazuya
Development of On-Board NH 3 and N 2 O Analyzer Utilizing Mid-Infrared Laser Absorption Spectroscopy2021-01-061004/06/2021
The authors present a portable NH3 and N2O analyzer utilizing mid-infrared laser absorption spectroscopy for on-board emission measurements. The developed analyzer employs a newly developed absorption spectroscopy named “infrared laser absorption modulation”, hereinafter referred to as IRLAM, for the signal acquisition and concentration determination. Because of IRLAM’s simple and robust signal processing scheme, a highly sensitive, selective and robust measurement system can be realized within a compact size. The following performance metrics of the new analyzer are presented: linearity, detection limit, response time and zero/span drift. Notably, the detection limit (defined as 2σ of the zero signal) of ≤ 0.1 ppm is achieved in both NH3 and N2O measurements. The influence of vibration, and changes in environment conditions such as ambient temperature and atmospheric pressure, are also tested. The effect of random vibrations had little observable impact on the measurement noise level
Onishi, Yusuke, Hamauchi, Shota, Shibuya, Kyoji, McWilliams-Ward, Keegan, Akita, Masanobu, Tsurumi, Kazuya
Quantum-Limit-Approaching Chemical Sensing ChipTBMG-3863903/01/2021
University at Buffalo researchers are reporting an advancement of a chemical sensing chip that could lead to handheld devices that detect trace chemicals — everything from illicit drugs to pollution — as quickly as a breathalyzer identifies alcohol.
Lenslet-Based Integral Field SpectrographTBMG-3799111/01/2020
An integral field spectrograph (IFS) is an instrument combining spectrographic and imaging capabilities. IFSs provide spectral information over a 2D field of view. In lenslet-based IFS designs, a lenslet array is placed in the spectrograph entrance plane. All beams generated by the lenslet array are fed through a dispersive element and imaged by a camera, resulting in a spectrum for each individual lenslet.
A Measurement of Fuel Filters’ Ability to Remove Soft Particles, with a Custom-Built Fuel Filter Rig2020-01-213009/15/2020
Biofuel can enable a sustainable transport solution and lower greenhouse gas emissions compared to standard fuels. This study focuses on biodiesel, implemented in the easiest way as drop in fuel. When mixing biodiesel into diesel one can run into problems with solubility causing contaminants precipitating out as insolubilities. These insolubilities, also called soft particles, can cause problems such as internal injector deposits and nozzle fouling. One way to overcome the problem of soft particles is by filtration. It is thus of great interest to be able to quantify fuel filters’ ability to intercept soft particles. The aim of this study is to test different fuel filters for heavy-duty engines and their ability to filter out synthetic soft particles. A custom-built fuel filter rig is presented, together with some of its general design requirements. For evaluation of the efficiency of the filters, fuel samples were taken before and after the filters. The fuel samples were analyzed with
Csontos, Botond, Hittig, Henrik, Pach, Mayte, Bernemyr, Hanna, Erlandsson, Anders
Ammonia Measurement Investigation Using Quantum Cascade Laser and Two Different Fourier Transform Infrared Spectroscopy Methods2020-01-036504/14/2020
Most diesel engine exhausts have been fitted with SCR (Selective Catalyst Reduction) in order to reduce NOX (Oxides of Nitrogen) by using NH3 (ammonia). However, both NOX and NH3 have been classified as compounds hazardous for the environment and human health. If the reaction between NOX and NH3 is unbalanced during treatment, it can lead to either NOX or NH3 being released into the environment. Accurate measurement is thus necessary. QCL (Quantum Cascade Laser) and FTIR (Fourier Transform InfraRed) are two methods that have been used to measure NH3 and NOX directly in diesel engine exhausts. However, only a few studies have compared those two methods of NH3 measurement, mainly from diesel engine exhausts. The aim of this paper is to compare the QCL and 2 different FTIR specifications for NH3 measurement directly from diesel engine exhausts under well-controlled laboratory conditions. Researchers have found that as NH3 is reactive, it is absorbed inside the exhaust pipe if the probe
Li, Nilton, El-Hamalawi, Ashraf, Barrett, Richard, Baxter, Jim
Durability Study of Automotive Additive Manufactured Specimens2020-01-095704/14/2020
The long-term weathering behavior of three different 3D printable, non-stabilized, UV cure resin formulations (A and B with thiol-ene base, and C with acrylate chemistry) was studied using tensile testing, nano-indentation, and photoacoustic infrared (FTIR-PAS) spectroscopy. To this end, type I tensile bars were printed from each resin system using a 3D printer, and were post UV-cured under a broad spectrum source. Systems A and C showed a similar trend after weathering. They first experienced an increase in modulus and tensile strength, due to additional crosslinking of the residual unreacted species. This increase in mechanical properties was followed by a drop in modulus, tensile strength, and percent elongation, due to the over-crosslinking and consequent embrittlement. System B, however, showed remarkable retention of the mechanical properties before/after weathering. Nano-indentation results were in good agreement with the tensile properties, showing a similar trend in hardness
Zareanshahraki, Forough, Davenport, Amelia, Cramer, Neil, Seubert, Christopher, Lee, Ellen, Cassoli, Matthew
Detailed Spectrometry Makes Dangerous-Materials Testing SaferTBMG-3639904/01/2020
Spinoff is NASA’s annual publication featuring successfully commercialized NASA technology. This commercialization has contributed to the development of products and services in the fields of health and medicine, consumer goods, transportation, public safety, computer technology, and environmental resources.
Fabrication and Electrical Characterization of Correlated Oxide Field Effect Switching Devices for High Speed Electronics20AERP04_1004/01/2020
The response of correlated oxides to strong electric fields and their dynamics is investigated using electrical transport measurements and electronic structure studies. Air Force Research Laboratory, Arlington, Virginia Metal insulator transitions (MITs) in oxides are an intriguing problem from both a fundamental materials physics and an applied technology perspective. Though the precise roles of electron correlations and lattice distortions on the phase transition remains an active area of research, many recent theoretical studies have suggested intimate interplay among the orbital splitting/polarization, correlation effects, and Peierls dimerization in the 3d1 system. Occupied states have been probed by x ray photoelectron spectros-copy (XPS), and a rough structure of unoccupied 3d-like states have been deduced by O K-edge x-ray absorption measurements. NbO2, a 4d1 system, like VO2 cry stallizes in a distorted rutile type structure with Nb dimers and undergoes a temperature induced
Researchers Hope to Make Needle Pricks for Diabetics a Thing of the PastTBMG-3624003/01/2020
Patients with diabetes have to test their blood sugar levels several times a day to make sure they are not getting too high or too low. Studies have shown that more than half of patients don’t test often enough, in part because of the pain and inconvenience of the needle prick.
Ultrasensitive Vapor Detection SystemTBMG-3597602/01/2020
An ultrasensitive technology detects explosive vapors, deadly chemicals, and illicit drugs and works in seconds. The ion chemistry technique initially identified RDX — a common explosive compound — at 10 parts per quadrillion (ppq). The original technology also identified explosive compounds such as C-4, PETN, Semtex, nitroglycerin, and tetryl. The system was enhanced to detect many more explosive vapors, including TNT, as well as vapors emanating from toxic chemicals similar in structure to nerve agents. The latest enhancement is the ability to detect vapors from illicit drugs such as fentanyl, methamphetamine, and cocaine.
Matrix-Free Assisted Laser Desorption Ionization Using Metal-Organic FrameworksTBMG-3453406/01/2019
Matrix-assisted laser desorption/ionization (MALDI) is a soft ionization technique that is widely applied in the characterization of large biomolecules using various mass spectrometry (MS) analyzers, specifically, time-of-flight (TOF) analyzers. The MALDI process involves the deposition of an analyte solution onto a metal substrate before the addition of a matrix. The matrix/analyte dry spot is exposed to a UV laser, and the laser energy that is absorbed by the matrix/analyte is converted into heat energy that initiates charge transfer, which results in the desorption of the matrix and analyte molecules in ionized form. The positive ions are then accelerated through a vacuum into MS analyses.
Matrix-Free Assisted Laser Desorption Ionization Using Metal-Organic Frameworks19AERP06_1006/01/2019
Army Research, Development and Engineering Command, Aberdeen Proving Ground, Maryland Matrix-assisted laser desorption/ionization (MALDI) is a soft ionization technique that is widely applied in the characterization of large biomolecules using various mass spectrometry (MS) analyzers, specifically, time-of-flight (TOF) analyzers. The MALDI process involves the deposition of an analyte solution onto a metal substrate before the addition of a matrix. The matrix/analyte dry spot is exposed to a UV laser, and the laser energy that is absorbed by the matrix/analyte is converted into heat energy that initiates charge transfer, which results in the desorption of the matrix and analyte molecules in ionized form. The positive ions are then accelerated through a vacuum into MS analyses. The MALDI process, however, lacks guiding systematic principles, which has resulted in mostly empirical work. For example, there is no universal matrix that can be used in the MALDI-MS analysis of biomolecules
Radiometric Temperature Measurement Using a DLP-Based PyrometerTBMG-3438905/01/2019
Researchers at NASA’s Armstrong Flight Research Center have identified and evaluated recently available miniature spectrometers that enable compact and robust pyrometry systems capable of measuring aircraft surface temperatures and emissivity during flight.
S-Curve Time-of-Flight Mass SpectrometerTBMG-3440605/01/2019
Time-of flight mass spectrometers are commonly used in analytical chemistry and many other applications. They contain a region where ions travel toward a detector. A new geometry was developed that has improved performance over existing designs.
Are Internal Diesel Injector Deposits (IDID) Mainly Linked to Biofuel Chemical Composition or/and Engine Operation Condition?2019-01-006101/15/2019
The increased use of alternative fuels has been linked to performance deterioration of injectors and engines as a result of internal diesel injector deposits (IDID). The present paper investigates fuel composition impact on injector tendency to blockage. Three main areas were investigated : (1) deposits linked to paraffins and aromatics content; (2) deposits linked to biodiesel composition using fatty acid methyl esters (FAME) and hydrotreated vegetal oil (HVO); and (3) deposits linked to the presence of additives (Dodecenylsuccinic anhydride DDSA, Dodecenyl Succinimid DDSI and Sodium Naphthenate). A deposit formation method was developed for the injection bench in order to discriminate the impact of fuels on system performance in terms of fuel volume injected, injection duration and stability. Three operation conditions were tested to represent low, intermediate and high load. In addition, the influence of soaking time and injector heating temperature was evaluated. The nature of the
Alves Fortunato, Maira, Lenglet, Francis, Ben Amara, Arij, Starck, Laurie
Control of the Diameter and Chiral Angle Distributions During Production of Single-Wall Carbon NanotubesTBMG-3360101/01/2019
Pulsed laser vaporization (PLV) production of single-wall carbon nanotubes (SWNTs) on traditional Co/Ni catalyst was explored with respect to variations in the production temperature. The Rh/Pd results were also reproduced for comparison. The nanotube-type populations were measured via photoluminescence (PL), UV-Vis-NIR (ultraviolet-visible-near-infrared) absorption, and Raman spectroscopy. A small reduction in the average nanotube diameter at lowered production temperature has long been known to occur; however, temperature effect on nanotube population (and not just for diameters) has never been explored.
New Catalyst for Plastic Production Also Creates HydrogenTBMG-3339012/01/2018
Researchers have developed a new, low-cost catalyst for plastic production that turns a biorefinery product into a starting material for the synthesis of plastics, which could represent a sustainable alternative to widespread PET. At the same time, hydrogen can also be formed during the reaction.
Device Assesses and Monitors Lymphedema NoninvasivelyTBMG-3344912/01/2018
Lymphedema is the swelling that generally occurs in the arms or legs caused by the removal of or damage to lymph nodes as a part of cancer treatment. Treating it at the earliest possible stage is the best way to manage the condition and prevent it from leading to pain, recurrent infection, reduced mobility, and impaired function.
Portable Acousto-Optic SpectrometersTBMG-3339812/01/2018
Spectrometers are widely used for applications such as chemical analysis, remote sensing, quality control, environmental monitoring, spaceborne measurements, and optical measurements. Most spectrometers are based on using dispersive elements such as prisms, gratings, or etalons. These spectrometers typically have moving parts that induce spurious readings due to vibrations, and have limited use due to their limited spectral range and resolution capabilities, which in turn limit their use when needed for portable field applications.
Spatial Resolution and Contrast of a Focused Diffractive Plenoptic CameraTBMG-3289809/01/2018
The concept of an imaging system that captures both spatial and spectral information has existed for a while. An example of one such imaging system that encodes both location and wavelength into an image is a Fourier Transform Spectrometer (FTS).
Promising Research Could Lead to New Strategies in NMR and MRI Using Diamonds and LasersTBMG-3246208/01/2018
Defects in the lattice of diamonds produce more than just beautiful coloration. A new approach developed by researchers at UC Berkeley's College of Chemistry shows great promise for enhancing the signal from magnetic resonance imaging (MRI) and nuclear magnetic resonance (NMR) using lasers without expensive magnets.
Miniature Mass SpectrometerTBMG-2886405/01/2018
For decades, mass spectrometers have offered a relatively fast and highly sensitive way to analyze and detect chemical compounds. But their bulky size has been a hindrance, limiting the in-field potential of the instruments. Though smaller spectrometers have been developed in the past, they’ve generally been less sensitive, and more likely to break down.
Mobile Instrument Detects and Samples Aerosol ParticlesTBMG-2884705/01/2018
Hazardous airborne particles pose a risk for health and safety in a variety of environments; thus, detection of these small particles is essential. Current particle magnification systems are bulky and require a lot of power for operation, making them unsuitable to easily detect and analyze small particles in mobile and personal settings.
Correlation SpectrometerTBMG-2884505/01/2018
Correlation spectroscopy is an attractive technique for sensing and analysis applications because it combines the attributes of mechanical and optical simplicity, high selectivity, and good sensitivity. In correlation spectroscopy, the degree of correlation between the transmission of an unknown sample and a reference cell containing a known target compound, or chemical species, is determined over a fixed spectral range.
A Novel Battery Impedance Model Considering Internal Temperature Gradient2018-01-043604/03/2018
Battery models are often applied to describe the dynamic characteristics of batteries and can be used to predict the state of the battery. Due to the process of charging and discharging, the battery heat generation will cause the inhomogeneity between inner battery temperature and surface temperature. In this paper, a novel battery impedance model, which takes the impact of the battery internal temperature gradient on battery impedance into account, is proposed to improve the battery model performance. Several experiments are designed and conducted for pouch typed battery to investigate the electrochemical impedance spectroscopy (EIS) characteristics with the artificial temperature gradient (using a heating plate). Experimental results indicate that the battery internal temperature gradient will influence battery EIS regularly. Using the experimental result without temperature gradient, and with the parameter identification based on particle swarm optimization (PSO), the relationship
Jiang, Bo, Dai, Haifeng, Zhu, Jiangong
Battery Impedance Measurement with Step Current of Different Amplitude under Temperature and State of Charge Control2018-01-044304/03/2018
Electrochemical Impedance Spectroscopy (EIS) is often applied to analyze and describe the battery internal electrochemical processes. And the methods of battery state estimation including state of health diagnosis with electrochemical impedance have attracted a wide attention. In the paper, a novel fast impedance measuring method based on wavelet transform with a step excitation current is proposed and further studied. With the method, the current generated by the electric vehicle and the responding voltage of the battery can be utilized to calculate and provide the battery impedance for the battery management system. Taking into account the varying amplitude of the current and the battery states, the battery impedance was measured with step excitation signals of different amplitude at different temperature and state of charge (SOC). Then the battery impedance was calculated with the proposed method and compared to the electrochemical impedance measured with an electrochemical
Wang, Xueyuan, Zhang, Junhan, Wei, Xuezhe, Dai, Haifeng
Cobalt Oxygen-Evolving Catalysts for Clean Solar FuelTBMG-2871204/01/2018
By splitting a water molecule into two atoms of hydrogen and one of oxygen, scientists can use the Sun’s energy to make a clean fuel. Splitting a water molecule requires a metal catalyst to get the reaction started. Recently, much scientific attention has focused on cobalt, a relatively abundant and inexpensive catalyst that — in the right circumstances — can serve as an escort to an electronic connection between hydrogens and oxygens.
Portable Electrochemical Sensing SystemTBMG-2853303/01/2018
Researchers at Pacific Northwest National Laboratory (PNNL) have developed an inexpensive electrochemical sensing system that significantly improves the ability to rapidly and accurately detect heavy metals in biological and environmental samples.
Fourier Transform Spectrometer SystemTBMG-2833602/01/2018
NASA's Langley Research Center and Science Applications International Corporation have developed a method of processing data from Fourier transform spectroscopy (FTS) measurements that improves upon existing methods. This method is simpler, more accurate, faster, and less expensive than previous methods. It uses less hardware and can be used with all wavelengths.
Nickel Oxide Compound for High-Temperature SuperconductorsTBMG-2817701/01/2018
Superconducting materials are technologically important because electricity flows through them without resistance. Only low-temperature superconductivity seemed possible before 1986, but materials that superconduct at low temperatures are impractical because they must first be cooled to hundreds of degrees below zero. In 1986, discovery of high-temperature superconductivity in copper oxide compounds, called cuprates, engendered new technological potential for the phenomenon.
Q&A: Dr. Raheem Beyah, Interim Steve W. Chaddick School Chair and Motorola Foundation Professor and Associate Chair, Georgia Tech School of Electrical and Computer Engineering, Atlanta, GATBMG-2827912/01/2017
Dr. Beyah and a team of researchers from Georgia Tech and Rutgers University have developed a three-layer system to verify that components produced using additive manufacturing have not been compromised.
Smartphone Device Performs Optical SpectroscopyTBMG-2762109/28/2017
Researchers have demonstrated that mobile devices incorporating their sensor can provide accurate measurements of optical absorption spectra of colored liquids or the optically scattered spectra of solid objects. In other words, a mobile device incorporating the lab-in-a-smartphone “science camera” could accurately read liquid-based or paper-based medical tests in which the end result is a material that changes from one color to another in the presence of a specific analyte.
Characterization and Discrimination of Aircrafts and Runways Winter Maintenance Anti-Icing Fluids2017-01-214009/19/2017
Aircrafts and runways de-icing operations with anti-icing fluids are still the most commonly used methods. In the specific case of aircrafts, they do contain glycols. Nevertheless, since two decades now, major environmental concerns are raised, along with important associated costs. Furthermore, once applied either on aircrafts or on runways, these fluids are diluted because of water brought from adverse weather conditions (rain, snow, icy conditions), conducting to increasing the freezing point from a subzero level to 0°C. The characterization of the freezing points of these fluids is indeed crucial for safety reasons. For years now, Raman spectroscopy is used for the characterization of these fluids, specifically the freezing point. But the presence of dyes did perturb the usual spectroscopic characterization. Three fluids, from their pure commercial form to highly diluted rate, were then studied by means of Raman spectroscopy at a new laser wavelength, and with the support of
Marchetti, Mario, Casteran, Guillaume, Jobard, Celine, Saintot, Bruno, Bourson, Patrice, Fontana, Marc
Optical Sensor for Unknown Gas DetectionTBMG-2750409/01/2017
Gas sensors are usually engineered to detect a specific molecule in one of many potential categories: toxic gases, combustible gases, and VOCs. A number of technologies, such as infrared, photoionization, catalytic, and electrochemical, are used to test for differing molecular species. Each method has specifications for resolution, sensitivity, temperature, and humidity range. Gas sensors are most useful when they have high sensitivity and flexibility in the gases they can detect.
Linear Fresnel Spectrometer Chip with Gradient Line GratingTBMG-2729108/01/2017
NASA's Langley Research Center has built a very small spectrometer by integrating a differential linear Fresnel lens onto an imaging chip. NASA is using the lens/chip in a very small spectrometer that will be mounted on the tires of a rover to analyze soil on the Moon or Mars. The spectrometer is useful for space-constrained applications. It combines good resolution with small size and potentially reduced manufacturing costs. The ultra-compact integration of the spectrometer is enabled by the use of an optimized Fresnel grating. Since Fresnel imaging works as valid focal points of spectrum within the short optical distance, the shorter optical path length required (compared to a traditional Fraunhofer lens) enables the small size. Further, the evolution to a differentially linear Fresnel lens (instead of circular Fresnel) avoids the need for aperture slit driver electronics and moving parts, and simplifies manufacturing. The linear Fresnel gratings lend themselves to mass production
Microhole Chip Allows Analysis of Single CellsTBMG-2712106/26/2017
A microhole chip allows single cells to be picked out of the blood sample, placed on separate holes in the substrate for analysis, and removed individually afterwards. A slight underpressure is applied to the cells that holds each one in its allotted place by suction.
Development of Photoacoustic Sensing PlatformsTBMG-2699906/01/2017
In recent years, photoacoustic spectroscopy (PAS) has emerged as an attractive and powerful technique well suited for sensing applications. The development of high-power radiation sources and more sophisticated electronics, including sensitive microphones and digital lock-in amplifiers, have allowed for significant advances in PAS. Furthermore, photoacoustic (PA) detection of IR absorption spectra using modern tunable lasers offers several advantages, including simultaneous detection and discrimination of numerous molecules of interest. Successful applications of PAS in gases and condensed matter have made this a notable technique and it is now studied and employed by scientists and engineers in a variety of disciplines.
Development of Photoacoustic Sensing Platforms17AERP06_1106/01/2017
Research focuses on sensor miniaturization and detection of chemical targets both proximally and at range. Army Research Laboratory, Adelphi, Maryland In recent years, photoacoustic spectroscopy (PAS) has emerged as an attractive and powerful technique well suited for sensing applications. The development of high- power radiation sources and more sophisticated electronics, including sensitive microphones and digital lock-in amplifiers, have allowed for significant advances in PAS. Furthermore, photoacoustic (PA) detection of IR absorption spectra using modern tunable lasers offers several advantages, including simultaneous detection and discrimination of numerous molecules of interest. Successful applications of PAS in gases and condensed matter have made this a notable technique and it is now studied and employed by scientists and engineers in a variety of disciplines. PAS is a detection technique under the umbrella of photothermal spectroscopy. Photothermal spectroscopy encompasses a
Method of Mapping Anomalies in Homogenous MaterialTBMG-2663504/01/2017
This innovation builds off of NASA Langley Research Center’s SansEC sensing system. SansEC is an open-circuit, resonant sensor that needs no electrical connections (thus the name SansEC or “without electrical connection”). This technology combines the SansEC circuit with a magnetic field reader to allow for detection of magnetic or electric field changes to produce a spectroscopy readout.
Surface Functional Groups and Graphitization Degree of Soot in the Sooting History of Methane Premixed Flame2017-01-100303/28/2017
The evolution of surface functional groups (SFGs) and the graphitization degree of soot generated in premixed methane flames are studied and the correlation between them is discussed. Test soot samples were obtained from an optimized thermophoretic sampling system and probe sampling system. The SFGs of soot were determined by Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) after removing the soluble impurities from the soot samples, while the graphitization degree of soot was characterized by Raman spectrum and electron energy loss spectroscopy (EELS). The results reveal that the number of aliphatic C-H groups and C=O groups shows an initial increase and then decrease in the sooting history. The large amount of aliphatic C-H groups and small amount of aromatic C-H groups in the early stage of the soot mass growth process indicate that aliphatic C-H groups make a major contribution to the early stage of soot mass growth. The higher
Liu, Ye, Lv, Gang, Fan, Chenyang, Li, Na, Wang, Xiaowei
Fourier Transform Spectrometer SystemTBMG-2647103/01/2017
NASA's Langley Research Center and Science Applications International Corporation have developed a method of processing data from Fourier transform spectroscopy (FTS) measurements that improves upon existing methods. This method is simpler, more accurate, faster, and less expensive than previous methods. It uses less hardware and can be used with all wavelengths.
Silicon Based Mid-Infrared SiGeSn Heterostructure Emitters and DetectorsTBMG-2638902/01/2017
Silicon Based Mid-Infrared SiGeSn Heterostructure Emitters and Detectors17AERP02_0702/01/2017
Enhancing the performance of GeSn p-i-n photodiodes using gold metal nanostructures. Air Force Research Laboratory, Arlington, Virginia The goal of this research project was to advance the science and technology of silicon-based photonic devices using SiGeSn heterostructures. Such devices work in mid-IR spectral range and form the foundation for mid-IR photonics that enable on-chip systems for applications ranging from vibrational spectroscopy, chem/bio sensing, medical/health uses, to environmental monitoring. This project was mostly directed toward improving GeSn detectors with the use of surface plasmons induced by carefully designed metal nanostructures. The goal was to replace the current mid-IR detectors that are usually photodiodes made from narrow bandgap III-V or II-VI semiconductor compounds such as InGaAs, InSb, HgCdTe (MCT) or type-II InGaAs/InGaSb superlattice. These photodiodes are incompatible with the CMOS process and cannot be easily integrated with Si electronics. The
High-Precision Electric Gate for Time-of-Flight Ion Mass SpectrometersTBMG-2618301/01/2017
NASA’s Goddard Space Flight Center has developed a high-precision electric gate (HPEG) time-of-flight (TOF) mass spectrometer to study the magnetosphere of Jupiter and Europa. The HPEG can provide a precise start pulse when an ion enters the TOF section of an Ion Mass Spectrometer (IMS) to provide a very high mass resolution capability. The design uses a row of very thin, parallel aligned wires that are pulsed in sequence so the ion can pass through the gap of two parallel plates, which are biased to prevent passage of the ion.
Development of a Metallic Bilayer Liftoff MaskTBMG-2531709/01/2016
A large variety of cryogenic detectors need to be fabricated on thin dielectric membranes in order to have high signal-to-noise attributes. Unfortunately, many of the etching processes used to define the detectors can roughen or even completely dissolve the membranes. These types of membrane damage degrade the detector performance and limit fabrication yield.
Ground Tactical Vision Comes Full-CircleTBMG-2505207/01/2016
The “always-true” use case for 360º vision systems is to avoid blind spots. Blind spots are a byproduct of conventional cameras. They have a limited field of view and they only see in the direction that they were pointed at. Point them to a new direction and you miss what happened at the old direction. 360º vision systems do not have this drawback. They are always “on”, in any view direction. Among their disadvantages we have seen, depending on their configuration: a trade-off between temporal (frame rate) and spatial (range) resolution, and a limitation to single EO/IR bands.
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