Infrared Measurements Research Articles

Visualization of orthodontic forces generated by aligner-type appliances.

Recently, the number of patients who request esthetically pleasing aligner-type orthodontic appliances (referred to as aligners) has been increasing. However, the orthodontic forces generated by these aligners are still unknown. This study aimed to verify whether the orthodontic force in aligners can be estimated by measuring near infrared 2D birefringence, and to visualize the orthodontic force. We measured the mechanical and photoelastic properties of transparent orthodontic thermoplastic specimens to correlate the optical retardation with the applied load. The results confirmed equivalence between the mechanical properties and the photoelasticity. In addition, the 2D retardation distribution that occurred when stress was applied to the sample was mapped and visualized. This indicates that it is possible to estimate and visualize the orthodontic force using the retardation obtained by near infrared 2D birefringence measurement.

A comparative study of interfacial environments in lipid nanodiscs and vesicles

Membrane protein conformations and dynamics are driven by the protein-lipid interactions occurring within the local environment of the membrane. These environments remain challenging to accurately capture in structural and biophysical experiments using bilayers. Consequently, there is an increasing need for realistic cell-membrane mimetics for in vitro studies. Lipid nanodiscs provide certain advantages over vesicles for membrane protein studies. Nanodiscs are increasingly used for structural and spectroscopic characterization of membrane proteins. Despite the common use of nanodiscs, the interfacial environments of lipids confined to a ∼10-nm diameter area have remained relatively underexplored. Here, we use ultrafast two-dimensional infrared spectroscopy and temperature-dependent infrared absorption measurements of the ester carbonyls to compare the interfacial hydrogen bond structure and dynamics in lipid nanodiscs of varying lipid compositions and sizes with ∼100-nm vesicles. We examine the effects of lipid composition and nanodisc size. We found that nanodiscs and vesicles share largely similar lipid-water H-bond environments and interfacial dynamics. Differences in measured enthalpies of H-bonding suggest that H-bond dynamics in nanodiscs are modulated by the interaction between the annular lipids and the scaffold protein.

Probing electrolyte-silica interactions through simulations of the infrared spectroscopy of nanoscale pores.

The structural and dynamical properties of nanoconfined solutions can differ dramatically from those of the corresponding bulk systems. Understanding the changes induced by confinement is central to controlling the behavior of synthetic nanostructured materials and predicting the characteristics of biological and geochemical systems. A key outstanding issue is how the molecular-level behavior of nanoconfined electrolyte solutions is reflected in different experimental, particularly spectroscopic, measurements. This is addressed here through molecular dynamics simulations of the OH stretching infrared (IR) spectroscopy of NaCl, NaBr, and NaI solutions in isotopically dilute HOD/D2O confined in hydroxylated amorphous silica slit pores of width 1-6nm and pH ∼2. In addition, the water reorientation dynamics and spectral diffusion, accessible by pump-probe anisotropy and two-dimensional IR measurements, are investigated. The aim is to elucidate the effect of salt identity, confinement, and salt concentration on the vibrational spectra. It is found that the IR spectra of the electrolyte solutions are only modestly blue-shifted upon confinement in amorphous silica slit pores, with both the size of the shift and linewidth increasing with the halide size, but these effects are suppressed as the salt concentration is increased. This indicates the limitations of linear IR spectroscopy as a probe of confined water. However, the OH reorientational and spectral diffusion dynamics are significantly slowed by confinement even at the lowest concentrations. The retardation of the dynamics eases with increasing salt concentration and pore width, but it exhibits a more complex behavior as a function of halide.

A Neural Network Based Single Footprint Temperature Retrieval for Atmospheric Infrared Sounder Measurements and Its Application to Study on Stratospheric Gravity Wave

Satellite hyperspectral infrared sounder measurements have better horizontal resolution than other sounding techniques as it boasts the stratospheric gravity wave (GW) analysis. To accurately and efficiently derive the three- dimensional structure of the stratospheric GWs from the single-field-of-view (SFOV) Atmospheric InfraRed Sounder (AIRS) observations, this paper firstly focuses on the retrieval of the atmospheric temperature profiles in the altitude range of 20-60 km with an artificial neural network approach (ANN). The simulation experiments show that the retrieval bias is less than 0.5 K, and the root mean square error (RMSE) ranges from 1.8 to 4 K. Moreover, the retrieval results from 20 granules of the AIRS observations with the trained neural network (AIRS_SFOV) and the corresponding operational AIRS products (AIRS_L2) as well as the dual-regression results from the Cooperative Institute for Meteorological Satellite Studies (CIMSS) (AIRS_DR) are compared respectively with ECMWF T799 data. The comparison indicates that the standard deviation of the ANN retrieval errors is significantly less than that of the AIRS_DR. Furthermore, the analysis of the typical GW events induced by the mountain Andes and the typhoon "Soulik" using different data indicates that the AIRS_SFOV results capture more details of the stratospheric gravity waves in the perturbation amplitude and pattern than the operational AIRS products do.

The Role of Molar Mass in Achieving Isotropy and Inter-Layer Strength in Mat-Ex Printed Polylactic Acid.

There has been extensive research in the field of material-extrusion (Mat-Ex) 3D printing to improve the inter-layer bonding process. Much research focusses on how various printing conditions may be detrimental to weld strength; many different feedstocks have been investigated along with various additives to improve strength. Surprisingly, there has been little attention directed toward how fundamental molecular properties of the feedstock, in particular the average molar mass of the polymer, may contribute to microstructure of the weld. Here we showed that weld strength increases with decreasing average molar mass, contrary to common observations in specimens processed in more traditional ways, e.g., by compression molding. Using a combination of synchrotron infra-red polarisation modulation microspectroscopy measurements and continuum modelling, we demonstrated how residual molecular anisotropy in the weld region leads to poor strength and how it can be eradicated by decreasing the relaxation time of the polymer. This is achieved more effectively by reducing the molar mass than by the usual approach of attempting to govern the temperature in this hard to control non-isothermal process. Thus, we propose that molar mass of the polymer feedstock should be considered as a key control parameter for achieving high weld strength in Mat-Ex.

Ice-VII-like Structure Observed By XRD in Water Confined in Silica Nanoholes

Water structuring has been proposed to occur in water confined in nanochannels and nanoholes based on shifts of the OH stretching peak in Attenuated Total Reflection – Fourier Transformed Infra-Red (ATR-FTIR) measurements (Vereecke, Micro. Eng., 2021 and 2022). Nanoconfined water was characterized by the presence of H-bonds with a stronger vibration frequency compared to ice. Using CO2 as a probe molecule in ATR-FTIR measurements on nanoholes, it was also shown that nanoconfined water was characterized by a slower diffusivity and a lower permittivity compared to bulk water (Vereecke, Micro. Eng., 2021), in agreement with previous studies performed using different techniques (Mawatari, Anal. Chem., 2014; Morikawa, Anal. Chem., 2015). Also, the decreased rate of a model surface reaction performed in nanotrenches of decreasing width correlated well with water structuring characterized by IR spectroscopy (Vereecke, Solid State Phenom., 2018). In the present study, X-Ray diffraction (XRD) measurements were used to further characterize the structuring of water confined in nanoholes.XRD measurements were performed on a X’pert Pro from Malvern Panalytical equipped with a PixCel detector. Measurements were performed on a parametric space defined by an incident XR angle w varying from 3 to 23°, and a spectra angle 2q varying from 12 to 42°. Measurements of 101 spectra with Dw = 0.2 took 2 days 7 hours. ATR-FTIR measurements were performed in a flow cell on crystals made from wafers as described in Vereecke (Micro. Eng., 2021). The cell was equipped with a bubbler filled with water to control the relative humidity (RH) of the N2 flow in the cell. Samples consisted in nanoholes in an oxide matrix with a diameter of about 20 nm and a depth of about 300 nm, manufactured on Si wafers as described in Vereecke (Micro. Eng., 2021). The last step in making the nanoholes structure consisted in a 30 min bake at 400 °C to remove any tetra-methyl ammonium hydroxide (TMAH) residue present in the holes from etching. The contact angle (CA) of pristine nanoholes was less than 5°. It was increased by silanization treatments. One treatment consisted in the classical HMDS priming photoresist pre-treatment, which gives a CA of about 70° on a flat Si substrate, while the second consisted in the SMT treatment developed by SCREEN, which gives a CA of about 80° on a flat Si substrate. These treatments were performed immediately after drying the sample to prevent any condensation before silanization.Long XRD measurements were made possible by the anomalous capillary condensation occurring in the 20 nm nanoholes. In turn, condensation was evidenced by ATR-FTIR measurements by monitoring the OH stretching peak. Condensation occurred in nanoholes submitted to a 200 °C bake in about 30 min when submitted to the clean-room air with a RH of about 40%. On the other hand, no condensation was observed in nanoholes under a N2 flow with a RH of about 30%, indicating that condensation was not an artefact, caused for example by the presence of impurities in the nanoholes, but was truly the result of capillary condensation.XRD measurements showed the presence of a small peak varying as a function of w, from about 2q = 28° at w = 15° to 2q = 33° at w = 18°, which was not present in the Si and oxide references. This peak was close to the 27° peak of ice-VII that has been identified by Raman spectroscopy measurements in water condensed in the nanomeniscus of nanoparticles (Shin, Nature Commun., 2019). The peak was not changed by ageing of the sample from 2 days to 2 months. It was also observed in samples that had been submitted to silanization treatments, bringing the CA on flat substrates from about 5° for the pristine sample, to 70° and 80° for the sample submitted to the HMDS priming and the SMT clean, respectively. This peak was evidence for structuring of water confined in nanoholes. Shifting of the peak as a function of w indicated that water structuring in nanoholes was comparable to a monocrystalline structure. However, the structure of nanoconfined water differed from that of ice-VII. Indeed, the presence of a broad peak at about 22°, which was not observed in the oxide reference, indicated the simultaneous presence of bulk H2O in the nanoholes. These observations added to our understanding of structured water in nanoholes that had been proposed previously based on ATR-FTIR measurements.

Low-profile inductive metasurface for surface wave excitation in L-band: design, manufacture and electromagnetic infrared measurements

This paper describes a low profile inductive surface for High Frequency Surface Wave Radars (HFSWR). The long-term operating frequency band considered is High Frequency (HF). In this paper we will only discuss L-band in order to simplify the manufacturing phase and the proof of concept. A compact thin 2D Super Inductive Surface (SIS) based on printed metal rings excited by an L-band monopole (1.1 GHz) is proposed to significantly increase (10 dB at the extremity of the SIS and 7 dB at one wavelength further) an electric field in TM polarization (electric field normal at the air/sea interface) required to excite a surface wave. The proposed SIS thickness 10.26 mm, is approximatly three times thinner than a recent 3D SIS developed both in L-band and HF-band which makes it possible to consider surface wave launchers of much lower height in the HF-band in the future. A 2D L-band prototype with a bandwidth of 130 MHz was manufactured and ElectroMagnetic Infrared measuRements (EMIR) confirmed simulated SIS performances.

Microstructural and Surface Plasmon Resonance Properties of Green-Synthesized Ag Nanoparticles Using <i>Moringa oleifera</i> Extract

Ag nanoparticles (NPs) have been successfully synthesized by the green synthesis method using Moringaoleifera (MO) extract with various incubation times (24 and 48 hours) as an active material for surface plasmon resonance (SPR) biosensor. Transmission electron microscopy analysis indicated the formation of spherical particles with an average crystal size of 29 nm. Selected area electron diffraction confirmed that Ag NPs is face-centered cubic (FCC) crystal structure. Fourier-transform infrared measurements show the band at 3330 cm-1, 2067 cm-1, 1634 cm-1 for an incubation time of 24 hours and 3328 cm-1, 2063 cm-1, 1633 cm-1 for an incubation time of 48 hours. The results prove the proteins and phenolics compound present in the MO extract responsible as reducing agents. The maximum absorption of the green-synthesized Ag NPs in the UV-Vis spectra shows the SPR band at 326 nm and 328 nm for an incubation time of 24 and 48 hours, respectively, and absorption intensity decrease with the increase of incubation time. The result shows the SPR angle shifted to the larger angle of incident light by using green-synthesized Ag NPs. However, the increased incubation time affects the angle shift to the lower angle of the SPR shift. The addition of the green-synthesized Ag NPs leads to enhance the sensitivity of the SPR biosensor.

Synergetic effect of nitrogen-doped carbon catalysts for high-efficiency electrochemical CO2 reduction

The use of carbon-based materials is an appealing strategy to solve the issue of excessive CO2 emissions. In particular, metal-free nitrogen-doped carbon materials (mf-NCs) have the advantages of convenient synthesis, cost-effectiveness, and high conductivity and are ideal electrocatalysts for the CO2 reduction reaction (CO2RR). However, the unclear identification of the active N sites and the low intrinsic activity of mf-NCs hinder the further development of high-performance CO2RR electrocatalysts. Achieving precise control over the synthesis of mf-NC catalysts with well-defined active N-species sites is still challenging. To this end, we adopted a facile synthesis method to construct a set of mf-NCs as robust catalysts for CO2RR. The resulting best-performing catalyst obtained a Faradaic efficiency of CO of approximately 90% at −0.55 V (vs. reversible hydrogen electrode) and good stability. The electrocatalytic performance and in situ attenuated total reflectance surface-enhanced infrared absorption spectroscopy measurements collectively revealed that graphitic and pyridinic N can synergistically adsorb CO2 and H2O and thus promote CO2 activation and protonation.

Ice-VII-like Structure Observed By XRD in Water Confined in Silica Nanoholes

In advanced semiconductor manufacturing, deep hydrophilic nanoholes are found in various applications, which require a wet clean after patterning. However, wetting of high aspect ratio nanoholes was showed to be incomplete for non-settled reasons. In this study, X-ray diffraction (XRD) was used to characterize water confined in deep nanoholes with 20 nm diameter. Long XRD measurements were made possible by the anomalous capillary condensation occurring in these nanoholes, which was proved by Attenuated Total Reflection – Fourier Transformed Infra-Red measurements. Condensation occurred in nanoholes submitted to the clean-room air with a relative humidity (RH) of about 40%, while no condensation was observed under a N2 flow with a RH of about 30%. XRD measurements showed the presence of small peaks varying as a function of the XR incidence angle, which were not present in the Si and oxide references. These peaks gave evidence for structuring of water confined in nanoholes.

Thermotropic Liquid Crystals for Temperature Mapping.

Wound management in Space is an important factor to be considered in future Human Space Exploration. It demands the development of reliable wound monitoring systems that will facilitate the assessment and proper care of wounds in isolated environments, such as Space. One possible system could be developed using liquid crystal films, which have been a promising solution for real-time in-situ temperature monitoring in healthcare, but they are not yet implemented in clinical practice. To progress in the latter, the goal of this study is twofold. First, it provides a full characterization of a sensing element composed of thermotropic liquid crystals arrays embedded between two elastomer layers, and second, it discusses how such a system compares against non-local infrared measurements. The sensing element evaluated here has an operating temperature range of 34–38°C, and a quick response time of approximately 0.25 s. The temperature distribution of surfaces obtained using this system was compared to the one obtained using the infrared thermography, a technique commonly used to measure temperature distributions at the wound site. This comparison was done on a mimicked wound, and results indicate that the proposed sensing element can reproduce the temperature distributions, similar to the ones obtained using infrared imaging. Although there is a long way to go before implementing the liquid crystal sensing element into clinical practice, the results of this work demonstrate that such sensors can be suitable for future wound monitoring systems.

A two-step deep learning framework for mapping gapless all-weather land surface temperature using thermal infrared and passive microwave data

Blending data from thermal infrared (TIR) and passive microwave (PMW) measurements is a promising solution for generating the all-weather land surface temperature (LST). However, owing to swath gaps in PMW data and the resolution inconsistence between TIR and PWM data, spatial details are often incomplete or considerable losses are generated in the all-weather LST using traditional methods. This study was conducted to develop a two-step deep learning framework (TDLF) for mapping gapless all-weather LST over the China's landmass using MODIS and AMSR-E LST data. In the TDLF, a multi-temporal feature connected convolutional neural network bidirectional reconstruction model was developed to obtain the spatially complete AMSR-E LST. A multi-scale multi-temporal feature connected generative adversarial network model was then designed to blend spatially complete AMSR-E LST and cloudy-sky MODIS LST, and generate gapless all-weather LST data. Gapless all-weather LST data were evaluated using six in-situ LST data from the Tibetan Plateau (TP) and the Heihe River Basin (HRB). The root mean squared errors (RMSEs) of the gapless all-weather LST were 1.71–2.0 K with determination coefficients (R2) of 0.94–0.98 under clear conditions, and RMSEs of 3.41–3.87 K and R2 of 0.88–0.94 were obtained under cloudy conditions. Compared to the existing PMW-based all-weather LSTs, the validation accuracy and image quality (such as spatial detail) of the generated gapless all-weather LSTs were superior. The TDLF does not require the use of any additional data and can potentially be implemented with other satellite TIR and PWM sensors to produce long-term, gapless, all-weather MODIS LST records on a global scale. Such a capability is beneficial for generating further gapless all-weather soil moisture and evapotranspiration datasets that can all be applied in global climate change research.

On the function of lead (Pb) in machining brass alloys

Lead has traditionally been added to brass alloys to achieve high machinability, but the exact mechanisms at work are still debated. Lead-free brass alternatives could be developed if these mechanisms were better understood. Accordingly, machinability characteristics were investigated for two brass alloys with similar mechanical properties and phase composition, but with very different machining characteristics because one has 3 wt.% lead (CuZn38Pb3) while the other has only 0.1 wt.% (CuZn42). The effect of the lead was investigated using infrared temperature measurement, electron microscopy, secondary ion mass spectroscopy, quick-stop methods, and high-speed filming. Neither melting of lead nor its deposition on the tool rake surface takes place during machining thus confirming its limited lubrication and tribological effects. Instead, the main role of lead is to promote discontinuous chip formation. Lead deforms to flake-like shapes that act as crack initiation points when the workpiece material passes through the primary deformation zone. This effect prevents the development of stable tool–chip contact, thus lowering cutting forces, friction, and process temperature.

Retrieving H<sub>2</sub>O/HDO columns over cloudy and clear-sky scenes from the Tropospheric Monitoring Instrument (TROPOMI)

Abstract. This paper presents an extended scientific HDO/H2O total column data product from short-wave infrared (SWIR) measurements by the Tropospheric Monitoring Instrument (TROPOMI) including clear-sky and cloudy scenes. The retrieval employs a forward model which accounts for scattering, and the algorithm infers the trace gas column information, surface properties, and effective cloud parameters from the observations. Compared to the previous clear-sky-only data product, coverage is greatly enhanced by including scenes over low clouds, particularly enabling data over oceans as the albedo of water in the SWIR spectral range is too low to retrieve under cloud-free conditions. The new dataset is validated against co-located ground-based Fourier transform infrared (FTIR) observations by the Total Carbon Column Observing Network (TCCON). The median bias for clear-sky scenes is 1.4×1021 molec cm−2 (2.9 %) in H2O columns and 1.1×1017 molec cm−2 (−0.3 %) in HDO columns, which corresponds to −17 ‰ (9.9 %) in a posteriori δD. The bias for cloudy scenes is 4.9×1021 molec cm−2 (11 %) in H2O, 1.1×1018 molec cm−2 (7.9 %) in HDO, and −20 ‰ (9.7 %) in a posteriori δD. At low-altitude stations, the bias is small at low and middle latitudes and has a larger value at high latitudes. At high-altitude stations, an altitude correction is required to compensate for different partial columns seen by the station and the satellite. The bias in a posteriori δD after altitude correction depends on sensitivity due to shielding by clouds and on realistic a priori profile shapes for both isotopologues. Cloudy scenes generally involve low sensitivity below the clouds, and since the information is filled up by the prior, a realistic shape of the prior is important for realistic total column estimation in these cases. Over oceans, aircraft measurements with the Water Isotope System for Precipitation and Entrainment Research (WISPER) instrument from a field campaign in 2018 are used for validation, yielding biases of −3.9 % in H2O and −3 ‰ in δD over clouds. To demonstrate the added value of the new dataset, a short case study of a cold air outbreak over the Atlantic Ocean in January 2020 is presented, showing the daily evolution of the event with single-overpass results.

Influence of preheating temperature and printing speed on interlaminar shear performance of laser‐assisted additive manufacturing for CCF/PEEK composites

AbstractContinuous carbon fiber reinforced poly‐ether–ether–ketone (CCF/PEEK) shows great potential in engineering applications attributed to superior mechanical properties together with excellent thermal and chemical resistance. In this study, a laser‐assisted additive manufacturing device was established to accurately collect and control the preheating temperature based on a coaxial infrared temperature measurement system. The influence on laser power consumption, interlaminar shear performance, and failure mechanism was investigated in condition of different preheating temperatures and printing speeds. Results indicated that the laser‐preheated specimens showed much higher ILSS with maximum values and increasing percentage reached 33.48 MPa and 157.0% compared to unpretreated specimens. With the increase of preheating temperature and printing speed, more laser power was consumed, while the ILSS and increasing percentage increased firstly and then decreased. The strengthening effect on the interlayer bonding was ascribed to promoting the penetration of PEEK molecular chain ends between adjacent layers, increasing the fluidity and enhancing the bonding effect between adjacent filament together with improving the impregnation behavior of the inner fibers. The proposed interlaminar strengthening method based on laser‐assisted preheating provides potential application prospects in aerospace and automotive industries.

THERMOVISION IN MEDICAL AND ENVIRONMENTAL APPLICATIONS

Thermovision offers a wide range of possible use in many areas of science. The paper presents applications of the thermovision technology with regard to healthcare and environmental issues. Apart from the literature review it also provides experimental results of the thermal image of the foot and surface temperature distributions as well as their analyses. The article lists common errors and limitations that need to be considered during infrared measurements to avoid significant mistakes at the stage of image analysis. The issue presented in the article is especially important because of reduced costs of the thermovision systems and their widespread availability to both private and institutional users.

Infrared Sensor ZTP-135SR and Its Application in Infrared Body Temperature Measurement

Body temperature is an essential physiological parameter. Conducting non-contact, fast and accurate measurement of temperature is increasing important under the background of COVID-19. The study introduces an infrared temperature measurement system based on the thermopile infrared temperature sensor ZTP-135SR. Extracting original temperature date of sensor, post-amplification and filter processing have been performed to ensure accuracy of the system. In addition, the temperature data of environmental compensation which obtained by polynomial fitting is added to the system to further improve measurement accuracy.

Development of an Environment and Climate Data Acquisition System (EC-DAQS) for Radio Propagation Studies

Most weather monitoring systems used for measuring meteorological parameters are imported. For many developing countries like Nigeria, importing measuring instruments is practically bedeviled with problems due to erratic exchange rates. This has hampered weather-related research especially in radio propagation studies where finite weather data are required. In the quest to develop a home-grown monitoring system, this paper presents an Environment and Climate data acquisition system (EC-DAQS). In the EC-DAQS, an Arduino Mega2560 microcontroller along with six environment and weather sensors were coded to measure, record and display atmospheric parameters. For digital signal processing and data logging, the sensors were interconnected to the microcontroller through an analogue-to-digital-converter (ADC). The measured data were displayed on a liquid crystal display (LCD) screen remotely connected to the controller. Temperature, Ultraviolet Violet (UV) rays, humidity and sound level were tested and calibrated with “off-the shelf” instruments. The mean bias error (MBE) and the root mean square error (RMSE) were used to validate the temperature readings from the EC-DAQS with readings from a standard infra-red thermometer. The low results of the MBE (0.16°C) and RMSE (0.51°C) – showed close proximity between the EC-DAQS and the standard infra-red digital thermometer measurements. Also, the equation obtained from modelling is a straight line of near unity slope (0.994) and a correlation of 99.98%. The EC-DAQS developed will be a useful meteorological instrument, and a suitable replacement for imported weather stations in terms of performance, cost and maintenance. It will also provide some invaluable data needed for radio-propagation research and applications.

Isotope removal experiment in JET-ILW in view of T-removal after the 2nd DT campaign at JET

A sequence of fuel recovery methods was tested in JET, equipped with the ITER-like beryllium main chamber wall and tungsten divertor, to reduce the plasma deuterium concentration to less than 1% in preparation for operation with tritium. This was also a key activity with regard to refining the clean-up strategy to be implemented at the end of the 2nd DT campaign in JET (DTE2) and to assess the tools that are envisaged to mitigate the tritium inventory build-up in ITER. The sequence began with 4 days of main chamber baking at 320 °C, followed by a further 4 days in which Ion Cyclotron Wall Conditioning (ICWC) and Glow Discharge Conditioning (GDC) were applied with hydrogen fuelling, still at 320 °C, followed by more ICWC while the vessel cooled gradually from 320 °C to 225 °C on the 4th day. While baking alone is very efficient at recovering fuel from the main chamber, the ICWC and GDC sessions at 320 °C still removed slightly higher amounts of fuel than found previously in isotopic changeover experiments at 200 °C in JET. Finally, GDC and ICWC are found to have similar removal efficiency per unit of discharge energy. The baking week with ICWC and GDC was followed by plasma discharges to remove deposited fuel from the divertor. Raising the inner divertor strike point up to the uppermost accessible point allowed local heating of the surfaces to at least 800 °C for the duration of this discharge configuration (typically 18 s), according to infra-red thermography measurements. In laboratory thermal desorption measurements, maintaining this temperature level for several minutes depletes thick co-deposit samples of fuel. The fuel removal by 14 diverted plasma discharges is analysed, of which 9, for 160 s in total, with raised inner strike point. The initial D content in these discharges started at the low value of 3%–5%, due to the preceding baking and conditioning sequence, and reduced further to 1%, depending on the applied configuration, thus meeting the experimental target.

Simulated multispectral temperature and atmospheric composition retrievals for the JPL GEO-IR Sounder

Abstract. Satellite measurements enable quantification of atmospheric temperature, humidity, wind fields, and trace gas vertical profiles. The majority of current instruments operate on polar orbiting satellites and either in the thermal and mid-wave or in the shortwave infrared spectral regions. We present a new multispectral instrument concept for improved measurements from geostationary orbit (GEO) with sensitivity to the boundary layer. The JPL GEO-IR Sounder, which is an imaging Fourier transform spectrometer, uses a wide spectral range (1–15.4 µm) encompassing both reflected solar and thermal emission bands to improve sensitivity to the lower troposphere and boundary layer. We perform retrieval simulations for both clean and polluted scenarios that also encompass different temperature and humidity profiles. The results illustrate the benefits of combining shortwave and thermal infrared measurements. In particular, the former adds information in the boundary layer, while the latter helps to separate near-surface and mid-tropospheric variability. The performance of the JPL GEO-IR Sounder is similar to or better than currently operational instruments. The proposed concept is expected to improve weather forecasting as well as severe storm tracking and forecasting and also benefit local and global air quality and climate research.