Optical Diagnostics

The integration of high-resolution imaging and artificial intelligence (AI) into gastrointestinal (GI) endoscopy marks a transformative leap in diagnostic accuracy and personalized therapy. With enhanced imaging modalities and AI-driven decision support systems, clinicians are now empowered to detect lesions at earlier stages and automate histopathological classification with unprecedented precision. This paper explores the dual evolution of optical technologies and AI in GI endoscopy, presenting evidence from contemporary literature on their clinical impact, limitations, and future directions.

The work presented here describes a method that allows three component velocity measurements to be made, quickly and non-intrusively, across a plane in a flow defined by a laser light sheet. The method, two frequency planar Doppler Velocimetry (2ν-PDV) is a modification of the Planar Doppler Velocimetry (PDV) technique, using only a single CCD camera, and sequential illumination of the flow using two frequencies, separated by about 700MHz. One illumination frequency lies on an absorption line of gaseous iodine, and the other just off the absorption line. The beams sequentially illuminate a plane within a seeded flow and Doppler-shifted scattered light passes through an iodine vapour cell onto the camera. The beam at a frequency off the absorption line is not affected by passage through the cell, and provides a reference image. The other beam encodes the velocity information as a variation in transmission dependent upon the Doppler shift. Use of a single camera ensures registration of the reference and signal images, which is the major problem in any spilt image system such as a two-camera imaging head, and cost efficiency is improved by the simplification of the system. A 2ν-PDV system was constructed using a continuous-wave Argon ion laser and acousto-optic modulators to produce two frequencies of illuminating laser light. This was combined with multiple imaging fibre bundles, to port three different views of the measurement plane to a CCD camera, allowing the measurement of three velocity components.

A Laser Extinction Method has been set up to provide twodimensional soot volume fraction field time history at a tunable frequency up to 70 Hz inside an axis-symmetric diffusion flame experiencing slow unsteady phenomena preserving the symmetry. The use of a continuous wave laser as the light source enables this repetition rate, which is an incremental advance in the laser extinction technique. The technique is shown to allow a fine description of the soot volume fraction field in a flickering flame exhibiting a 12.6 Hz flickering phenomenon. Within this range of repetition rate, the technique and its subsequent post-processing require neither any method for time-domain reconstruction nor any correction for energy intrusion. Possibly complemented by such a reconstruction method, the technique should support further soot volume fraction database in oscillating flames that exhibit characteristic times relevant to the current efforts in the validation of soot processes modeling.

Objectives: Our study validates the preliminary steps needed to introduce
FT-IR spectroscopy as a point-of-care diagnostic tool, particularly for
patients at high risk for cancer.
Materials and methods: FT-IR spectroscopy was used to determine
molecular changes and classify saliva samples of control, smoker, and
occasional smoker groups.
Results: Correctly classified instances were 72.7% for the control group,
65.5% for occasional smokers and 75% for smokers. Sample differences
were observed in the peaks at 1076cm-1, 1403cm-1 symmetric CH3
modes
of protein methyl groups and δs
CH3
of collagen, 1451cm-1 asymmetrical
CH3
bending modes of the protein methyl groups, 1547cm-1 of protein
band, amide II, peptide and proteins amide II, and 1646cm-1 amide I, C5

methylated cytosine, C==O bond, C==C stretching uracil and NH2
guanine.

The jet in crossflow, or transverse jet, is a canonical flowfield that has relevance to engineering systems ranging from dilution jets and film cooling for gas turbine engines to thrust vector control and fuel injection in high speed aerospace vehicles to environmental control of effluent from chimney and smokestack plumes. Over the years, our UCLA Energy and Propulsion Research Lab's studies on this flowfield have focused on the dynamics of the vorticity associated with equidensity and variable density jets in crossflow, including the stability characteristics of the jet's upstream shear layer. A range of different experimental diagnostics have been used to study the jet's upstream shear layer, whereby a transition from convectively unstable behavior at high jet-to-crossflow momentum flux ratios to absolutely unstable flow at low momentum flux and/or density ratios is identified. These differences in shear layer stability characteristics have a profound effect on how one employs external excitation to control jet penetration, spread, and mixing, depending on the flow regime and specific engineering application. These control strategies, and challenges for future research directions, will be identified in this presentation.

Je souhaite donc ici remercier le CNRS et RENAULT pour avoir cofinancé cette thèse. Je remercie également Michel CHAMPION et Henri-Noël PRESLES, successivement directeurs du LCD, de m'avoir accueilli dans leur laboratoire. Mes remerciements s'adressent spécialement à Tadashi KAGEYAMA et Marc BELLENOUE, qui m'ont initié à la recherche dans l'équipe Moteurs. Je tiens à remercier chaleureusement Marc BELLENOUE pour son soutien inconditionnel durant ces trois années de thèse, ainsi que pour sa confiance et son amitié. Je suis aussi reconnaissant envers Julien SOTTON d'avoir coencadré ce travail, après l'avoir soigneusement préparé durant sa propre thèse de doctorat. J'aimerais remercier par ailleurs Sergei LABUDA pour sa grande patience, ainsi que pour ses précieux conseils expérimentaux et expérimentés. J'exprime aussi toute ma gratitude à Afif AHMED, Emma BRIEC et Jean-Pierre RIVÈRE, qui ont fait bénéficier cette étude de l'expertise de RENAULT et ont participé à ses orientations majeures. Ma gratitude va également à André AGNERAY, Alain FLOCH et Thomas MANSION, pour leur pragmatisme et leurs conseils avisés. Parmi les membres du Jury, je remercie particulièrement Christine ROUSSELLE et Michel TRINITÉ, qui ont rapporté avec bienveillance et sagacité ce volumineux manuscrit. De plus, je remercie vivement Gilles BRUNEAUX d'avoir examiné cette étude, après avoir apporté une contribution de taille à ce thème de recherche lors de sa propre thèse de doctorat. Enfin, j'exprime ma profonde reconnaissance à Alain CLAVERIE, pour sa maîtrise des diagnostics et sa persévérance joyeuse dans les campagnes de mesure. Je souhaite aussi remercier Baldeo RUTTUN pour sa disponibilité et sa présence sympathique sur le terrain. Je remercie également Monique DUPUY, Françoise ASTIER, Éliane BONNEAU et particulièrement Jocelyne BARDEAU, pour leur aide précieuse au quotidien. Je veux enfin remercier Yves SÉCHERET, Lionel PUCHAULT,

layers (USL) in the absence of excitation. For sinusoidal excitation, the USL instability becomes "locked-in" to the forcing frequency f f , overtaking its natural frequency f o at two critical conditions f f,cr for each amplitude, one below and one above f o. Lock-in characteristics are observed for the absolutely unstable USL, as expected, but also for the convectively unstable USL, although with slightly different scaled frequency ranges. Acetone planar laser-induced fluorescence (PLIF) imaging shows that lock-in, especially with forcing frequencies close to f o , enhances cross-sectional symmetry as well as molecular mixing for the convectively unstable USL at large J, e.g., J = 41, but with reduced jet penetration. For the absolutely unstable USL at a low J value, e.g., J = 5, lock-in is observed to have a lesser impact on structure and mixing, but with the same general trends as for convectively unstable conditions.

Submitted for the DFD17 Meeting of The American Physical Society An adaptive control process for the temporal shaping of a jet in cross flow 1 STEPHEN SCHEIN, TAKESHI SHOJI, ANN KARAGOZIAN, ROBERT M'CLOSKEY, UCLA-This study demonstrates an iterative process for shaping the temporal exit velocity for a gaseous jet in crossflow (JICF). Alternative temporal velocity waveforms, typically measured via hotwire anemometry at the center of the nozzle exit, can significantly affect JICF mixing characteristics 2. The most challenging waveforms to create are those with rapid transitions in the jet velocity, e.g., single-and double-pulse square waves. While linear models of the jet velocity actuation can be empirically determined and used, in practice they yield poor reproductions of the desired waveforms because the jet velocity is a highly nonlinear function of the actuation variable. This research presents an approach to improve waveform control by using the periodicity of the desired velocity deviation relative to the mean jet velocity. A local model relating perturbations of the harmonics in the input variable to jet velocity harmonics is empirically determined, providing a means to adjust the input harmonics so that the jet profile converges to the desired signal. The process is necessarily iterative because the local model must be re-identified at each new operating point, but the scheme converges rapidly under a variety of flow conditions.

The first mirrors of optical diagnostics in ITER are exposed to high radiation and fluxes of particles which escape the plasma, in the order of 10 20 m −2 s −1. At the position of the mirror, the flux may still reach about 10 18 m −2 s −1. First mirrors are thus the most vulnerable in-vessel optical components, being subject to erosion, esp. by fast charge-exchange neutrals, or to deposition of impurities at flux rates which can reach 0.05 nm/s. The material selected for the reflecting surface must combine a high optical reflectivity in a wide spectral range and a sufficient resistance to physical sputtering during normal operation and during mirror cleaning discharges, if any is installed. Rhodium (103 Rh) was identified early as a possible or even promising candidate. It combines several attractive properties, for instance a mass which leads in most cases to low sputtering yields together with an optical reflectance (75% Rh) which is much higher than of some other options. Rh is insensitive to large temperature changes. Rhodium is fairly inert and its low oxidation is an appreciable advantage in case of steam ingress events. The core-plasma CXRS diagnostic in ITER (UPP 3) have now turned to Rh as a baseline. The aim is to procure monocrystalline rhodium (SC-Rh) to mitigate the increase of the diffuse reflection with the damage due to physical sputtering.

We report the development, thorough characterizations and space worthiness studies of multifunctional aluminized film as x-ray intensity filter for space-based payloads, suitably designed to place in Sun-Earth Lagrangian (L1) point. The L1 point is the ideal location for uninterrupted observation of Sun to study the solar flares in hard x-rays. For our specific purpose, we make use of two different types of x-ray detectors (e.g., CdTe and CZT) which are generally used for hard x-ray studies in the energy band of 5 to 200 keV. Further, these aforesaid two detectors require specified thermal control characteristic for optimal performance. Aluminization of Kapton films is proposed which would satisfy the thermo-optical and x-ray transmission requirements of the proposed payload. The developed aluminized films are thoroughly studied by field emission scanning electron microscopy and atomic force microscopy techniques for micro-structural characteristic, x-ray diffraction for phase purity, nanoindentation for mechanical integrity at microstructural length scale and spectrophotometer for thermo-optical properties. X-ray transmission test is carried out with two radioactive sources, namely 55 Fe and 241 Am, with various aluminized Kapton layer combinations. Finally, space worthiness of the aluminized Kapton films is examined by accelerated environments, e.g. humidity, thermal cycling and thermo-vacuum tests.

A gigahertz (GHz) range antenna formed by a coaxial probe has been applied for sensing cancerous breast lesions in the scanning platform with the assistance of a suction tube. The sensor structure was a planar central layer and a metallic sheath of size of 3 cm2 connected to a network analyzer (keySight FieldFox N9918A) with operational bandwidth up to 26.5 GHz. Cancer tumor cells have significantly higher water content (as a dipolar molecule) than normal breast cells, changing their polarization responses and dielectric losses to incoming GHz-based stimulation. Principal component analysis named S11, related to the dispersion ratio of the input signal, is used as a parameter to identify malignant tumor cells in a mouse model (in vivo) and tumor specimens of breast cancer patients (in vitro) (both central and marginal parts). The results showed that S11 values in the frequency range from 5 to 6 GHz were significantly higher in cancer-involved breast lesions. Histopathological analys...

We present a silicon based metamaterial, Black Silicon in our case, which exhibits a very high wide band spectral emissivity in the spectral range of thermal radiation, up to 8 µm, which can be used as a broadband emitter. Black Silicon is a bottom-up nano-structured silicon surface that can be created using a variety of processes, such as wafer-level cryogenic plasma etching in our case. After demonstrating previously that the use of a heavily doped silicon wafer to fabricate Black Silicon can extend such remarkable emissivity to the mid-infrared (MIR) and touching the far-infrared (FIR) spectrum, we now report on the spectral hemispherical emissivity of BSi measured by both indirect and direct radiometric methods. The emissivity values obtained by the two methods are in good agreement.

We present a silicon based metamaterial, Black Silicon in our case, which exhibits a very high wide band spectral emissivity in the spectral range of thermal radiation, up to 8 µm, which can be used as a broadband emitter. Black Silicon is a bottom-up nano-structured silicon surface that can be created using a variety of processes, such as wafer-level cryogenic plasma etching in our case. After demonstrating previously that the use of a heavily doped silicon wafer to fabricate Black Silicon can extend such remarkable emissivity to the mid-infrared (MIR) and touching the far-infrared (FIR) spectrum, we now report on the spectral hemispherical emissivity of BSi measured by both indirect and direct radiometric methods. The emissivity values obtained by the two methods are in good agreement.

На основі існуючих методів оптоелектронної діагностики параметрів життєдіяльності організму розроблений прилад, що визначає оптичні параметри біологічних рідин з метою підвищення точності досліджень. Проведено аналіз оптоелектронних показників прилада й ступеня сатурації крові Ключові слова: оптична діагностика, оксиметрія, оптоелектронні прилади На основе существующих методов оптоэлектронной диагностики параметров жизнедеятельности организма разработан прибор, определяющий оптические параметры биологических жидкостей с целью повышения точности исследований. Проведен анализ оптоэлектронных показателей прибора и степени сатурации крови Ключевые слова: оптическая диагностика, оксиметрия, оптоэлектронные приборы On the basis of existing methods of optical electronic diagnostics of organism' live ability parameters the device defining optical parameters of biological fluids for the purpose of increase of researches' accuracy is developed. The analysis optical electronic device' indexes and degree of saturation of blood is carried out Keywords: optical diagnostics, oxygen measurements, the optical electronic devices С. С. Г р и н ь к о Аспирант* Контактный тел.: (0552) 32-69-44 А. И. Д е н и с е н к о Кандидат медицинских наук, заведующий отделением анестезиологии и интенсивной терапии КУ «Херсонская клиническая больница им. А. и О. Тропиных» г. Херсон, Украина, 73000 А. А. Н о в и к о в а Кандидат технических наук, доцент* Контактный тел.

На основі існуючих методів оптоелектронної діагностики параметрів життєдіяльності організму розроблений прилад, що визначає оптичні параметри біологічних рідин з метою підвищення точності досліджень. Проведено аналіз оптоелектронних показників прилада й ступеня сатурації крові Ключові слова: оптична діагностика, оксиметрія, оптоелектронні прилади На основе существующих методов оптоэлектронной диагностики параметров жизнедеятельности организма разработан прибор, определяющий оптические параметры биологических жидкостей с целью повышения точности исследований. Проведен анализ оптоэлектронных показателей прибора и степени сатурации крови Ключевые слова: оптическая диагностика, оксиметрия, оптоэлектронные приборы On the basis of existing methods of optical electronic diagnostics of organism' live ability parameters the device defining optical parameters of biological fluids for the purpose of increase of researches' accuracy is developed. The analysis optical electronic device' indexes and degree of saturation of blood is carried out Keywords: optical diagnostics, oxygen measurements, the optical electronic devices С. С. Г р и н ь к о Аспирант* Контактный тел.: (0552) 32-69-44 А. И. Д е н и с е н к о Кандидат медицинских наук, заведующий отделением анестезиологии и интенсивной терапии КУ «Херсонская клиническая больница им. А. и О. Тропиных» г. Херсон, Украина, 73000 А. А. Н о в и к о в а Кандидат технических наук, доцент* Контактный тел.

Increased operations of aircraft, both commercial and military, in hostile desert environments have increased risks of micro-sized particle ingestion into engines. The probability of increased sand and dust ingestion results in increased life cycle costs, in addition to increased potential for performance loss. Thus, abilities to accurately characterize inlet sand would be useful for engine diagnostics and prognostic evaluation. Previous characterization studies were based on particle measurements performed a posteriori. Thus, there exists a need for in situ quantification of ingested particles. The work presented in this thesis describes initial developments of a line-of-sight optical technique to characterize ingested particles at concentrations similar to those experienced by aircraft in brownout conditions using light extinction with the end goal of producing an onboard aircraft diagnostic sensor. By measuring the extinct light intensity in presence of particles over range of co...

Optical medical imaging techniques in general exhibit outstanding resolution and molecule-specific contrast. They come however with a limited penetration in depth and small field of view. Multimodal concepts help to combine complementary strengths of different imaging technologies. The present article reviews the advantages of optical multimodal imaging concepts using optical coherence tomography (OCT) as core technology. In particular we first discuss polarization sensitive OCT, Doppler OCT and OCT angiography, OCT elastography, and spectroscopic OCT as intramodal concepts. To highlight intermodal imaging concepts, we then chose the combination of OCT with photoacoustics, and with non-linear optical microscopy. The selected multimodal concepts and their particular complementary strengths and applications are discussed in detail. The article concludes with notes on standardization of OCT imaging and multimodal extensions.

A gigahertz (GHz) range antenna formed by a coaxial probe has been applied for sensing cancerous breast lesions in the scanning platform with the assistance of a suction tube. The sensor structure was a planar central layer and a metallic sheath of size of 3 cm2 connected to a network analyzer (keySight FieldFox N9918A) with operational bandwidth up to 26.5 GHz. Cancer tumor cells have significantly higher water content (as a dipolar molecule) than normal breast cells, changing their polarization responses and dielectric losses to incoming GHz-based stimulation. Principal component analysis named S11, related to the dispersion ratio of the input signal, is used as a parameter to identify malignant tumor cells in a mouse model (in vivo) and tumor specimens of breast cancer patients (in vitro) (both central and marginal parts). The results showed that S11 values in the frequency range from 5 to 6 GHz were significantly higher in cancer-involved breast lesions. Histopathological analys...

The present paper discusses the experimental investigations on the flame induced by fuel film deposition ignition in a single cylinder, ported fuel injection, four-stroke, over-boosted spark-ignition engine with a four-valve production head. The engine was optically accessible and equipped with a transparent quartz window in the bottom of the combustion chamber. 2D-digital imaging and UV-visible natural emission spectroscopy were used to follow the flame propagation in the combustion chamber. Two colour pyrometers were applied to evaluate flame temperature and soot concentration. Particulate matter and soot primary particles diameters were measured and correlated with the soot amount produced in the combustion chamber. The effect of the intake air pressure and injection phasing was investigated. Optical setup for spectroscopic measurements and visible digital imaging, visible flame emission detected in the chamber for the selected operating conditions, visible emission spectra measured at 60 CAD ASOS in the chamber, soot concentration measured at the selected operating conditions, integral soot concentration measured at the selected operating conditions, particulate mass concentration measured by the Opacimeter and particles number concentration measured by LII at the engine exhaust are presented in the paper.

A Laser Extinction Method has been set up to provide twodimensional soot volume fraction field time history at a tunable frequency up to 70 Hz inside an axis-symmetric diffusion flame experiencing slow unsteady phenomena preserving the symmetry. The use of a continuous wave laser as the light source enables this repetition rate, which is an incremental advance in the laser extinction technique. The technique is shown to allow a fine description of the soot volume fraction field in a flickering flame exhibiting a 12.6 Hz flickering phenomenon. Within this range of repetition rate, the technique and its subsequent post-processing require neither any method for time-domain reconstruction nor any correction for energy intrusion. Possibly complemented by such a reconstruction method, the technique should support further soot volume fraction database in oscillating flames that exhibit characteristic times relevant to the current efforts in the validation of soot processes modeling.

A gigahertz (GHz) range antenna formed by a coaxial probe has been applied for sensing cancerous breast lesions in the scanning platform with the assistance of a suction tube. The sensor structure was a planar central layer and a metallic sheath of size of 3 cm2 connected to a network analyzer (keySight FieldFox N9918A) with operational bandwidth up to 26.5 GHz. Cancer tumor cells have significantly higher water content (as a dipolar molecule) than normal breast cells, changing their polarization responses and dielectric losses to incoming GHz-based stimulation. Principal component analysis named S11, related to the dispersion ratio of the input signal, is used as a parameter to identify malignant tumor cells in a mouse model (in vivo) and tumor specimens of breast cancer patients (in vitro) (both central and marginal parts). The results showed that S11 values in the frequency range from 5 to 6 GHz were significantly higher in cancer-involved breast lesions. Histopathological analys...

A gigahertz (GHz) range antenna formed by a coaxial probe has been applied for sensing cancerous breast lesions in the scanning platform with the assistance of a suction tube. The sensor structure was a planar central layer and a metallic sheath of size of 3 cm2 connected to a network analyzer (keySight FieldFox N9918A) with operational bandwidth up to 26.5 GHz. Cancer tumor cells have significantly higher water content (as a dipolar molecule) than normal breast cells, changing their polarization responses and dielectric losses to incoming GHz-based stimulation. Principal component analysis named S11, related to the dispersion ratio of the input signal, is used as a parameter to identify malignant tumor cells in a mouse model (in vivo) and tumor specimens of breast cancer patients (in vitro) (both central and marginal parts). The results showed that S11 values in the frequency range from 5 to 6 GHz were significantly higher in cancer-involved breast lesions. Histopathological analys...

The first mirrors of optical diagnostics in ITER are exposed to high radiation and fluxes of particles which escape the plasma, in the order of 10 20 m −2 s −1. At the position of the mirror, the flux may still reach about 10 18 m −2 s −1. First mirrors are thus the most vulnerable in-vessel optical components, being subject to erosion, esp. by fast charge-exchange neutrals, or to deposition of impurities at flux rates which can reach 0.05 nm/s. The material selected for the reflecting surface must combine a high optical reflectivity in a wide spectral range and a sufficient resistance to physical sputtering during normal operation and during mirror cleaning discharges, if any is installed. Rhodium (103 Rh) was identified early as a possible or even promising candidate. It combines several attractive properties, for instance a mass which leads in most cases to low sputtering yields together with an optical reflectance (75% Rh) which is much higher than of some other options. Rh is insensitive to large temperature changes. Rhodium is fairly inert and its low oxidation is an appreciable advantage in case of steam ingress events. The core-plasma CXRS diagnostic in ITER (UPP 3) have now turned to Rh as a baseline. The aim is to procure monocrystalline rhodium (SC-Rh) to mitigate the increase of the diffuse reflection with the damage due to physical sputtering.

Explosively driven magnetic flux compression (MFC) has been object of research for more than three decades. Actual interest in the basic physical picture of flux compression has been heightened by a newly started Department of Defense (DoD) Multi-University Research Initiative. The emphasis is on helical flux compression generators comprising a hollow cylindrical metal liner filled with high explosives and at least one helical coil surrounding the liner. After the application of a seed current, magnetic flux is trapped and high current is generated by moving, i.e., expanding, the liner explosively along the winding of the helical coil. Several key factors involved in the temporal development can be addresses by optical diagnostics. 1) The uniformity of liner expansion is captured by framing camera photography and supplemented by laser illuminated high spatial and temporal resolution imaging. Also, X-ray flash photography is insensitive to possible image blur by shockwaves coming from the exploding liner. 2) The thermodynamic state of the shocked gas is assessed by spatially and temporally resolved emission spectroscopy. 3) The moving liner-coil contact point is a possible source of high electric losses and is preferentially monitored also by emission spectroscopy. Since optical access to the region between liner and coil is not always guaranteed, optical fibers can be used to extract light from the generator. The information so gained will give, together with detailed electrical diagnostics, more insight in the physical loss mechanisms involved in MFC.

A gigahertz (GHz) range antenna formed by a coaxial probe has been applied for sensing
cancerous breast lesions in the scanning platform with the assistance of a suction tube. The sensor
structure was a planar central layer and a metallic sheath of size of 3 cm2 connected to a network
analyzer (keySight FieldFox N9918A) with operational bandwidth up to 26.5 GHz. Cancer tumor cells
have significantly higher water content (as a dipolar molecule) than normal breast cells, changing their
polarization responses and dielectric losses to incoming GHz-based stimulation. Principal component
analysis named S11, related to the dispersion ratio of the input signal, is used as a parameter to identify
malignant tumor cells in a mouse model (in vivo) and tumor specimens of breast cancer patients
(in vitro) (both central and marginal parts). The results showed that S11 values in the frequency
range from 5 to 6 GHz were significantly higher in cancer-involved breast lesions. Histopathological
analysis was the gold standard for achieving the S11 calibration to distinguish normal from cancerous
lesions. Our calibration on tumor specimens presented 82% positive predictive value (PPV), 100%
negative predictive value (NPV), and 86% accuracy. Our goal is to apply this system as an in vivo
non-invasive tumor margin scanner after further investigations in the future.

We present a new compact electron gun based on the secondary emission through ionic bombardment principle. The driving parameters to develop such a gun are to obtain a quite small electron gun for an in-flight instrument performing Electron Beam Fluorescence measurements (EBF) on board of a reentry vehicle in the upper atmosphere. These measurements are useful to characterize the gas flow around the vehicle in terms of gas chemical composition, temperatures and velocity of the flow which usually presents thermo-chemical non-equilibrium. Such an instrument can also be employed to characterize the upper atmosphere if placed on another carrier like a balloon. In ground facilities, it appears as a more practical tool to characterize flows in wind tunnel studies or as an alternative to complex electron guns in industrial processes requiring an electron beam. We describe in this paper the gun which has been developed as well as its different features which have been characterized in the laboratory.

The first mirrors of optical diagnostics in ITER are exposed to high radiation and fluxes of particles which escape the plasma, in the order of 10 20 m −2 s −1. At the position of the mirror, the flux may still reach about 10 18 m −2 s −1. First mirrors are thus the most vulnerable in-vessel optical components, being subject to erosion, esp. by fast charge-exchange neutrals, or to deposition of impurities at flux rates which can reach 0.05 nm/s. The material selected for the reflecting surface must combine a high optical reflectivity in a wide spectral range and a sufficient resistance to physical sputtering during normal operation and during mirror cleaning discharges, if any is installed. Rhodium (103 Rh) was identified early as a possible or even promising candidate. It combines several attractive properties, for instance a mass which leads in most cases to low sputtering yields together with an optical reflectance (75% Rh) which is much higher than of some other options. Rh is insensitive to large temperature changes. Rhodium is fairly inert and its low oxidation is an appreciable advantage in case of steam ingress events. The core-plasma CXRS diagnostic in ITER (UPP 3) have now turned to Rh as a baseline. The aim is to procure monocrystalline rhodium (SC-Rh) to mitigate the increase of the diffuse reflection with the damage due to physical sputtering.

A nanosecond repetitively pulsed plasma (NRPP) produced by electric pulses of 10 kV during 10 ns at a frequency of up to 30 kHz has been used to stabilize and improve the efficiency of a 25-kW lean turbulent premixed propane/air flame (Re D = 30 000) at atmospheric pressure. We show that, when placed in the recirculation zone of the flow, the plasma significantly increases the heat release and the combustion efficiency, thus allowing to stabilize the flame under lean conditions where it would not exist without plasma. Stabilization is obtained with a very low level of plasma power of about 75 W, or 0.3% of the maximum power of the flame. In addition, they find that at high flow rates, where the flame should normally blow out, the NRPP allows the existence of an intermittent V-shaped flame with significant heat release, and at even higher flow rates the existence of a small dome-shaped flame confined near the electrodes that can serve as a pilot flame to reignite the combustor. Optical emission spectroscopy measurements are presented to determine the temperature of the plasma-enhanced flame, the electron number density, and to identify the active species produced by the plasma, namely O, H, and OH.

The presence of dental calculus is highly correlated with the formation and advancement of periodontal disease. The occurrence and relapse of periodontal disease can be prevented only if dental calculus is completely removed. In this study, optical coherence tomography (OCT) is used to obtain two-dimensional cross-sectional images of tooth samples, in conjunction with a segmentation technique that enables automatic identification of dental calculus. We propose the vertical intensity transform function to correct the nonuniform instrument signal intensity caused by OCT. Afterwards, the detection ranges are defined by K-means or the Markov random field (MRF), and the candidate range is selected on the basis of mathematical morphology (MM). Finally, the features (thickness gradient, texture, and tooth surface slope) are quantified, and dental calculus is recognized and segmented. In the preliminary result, the sensitivity is 87.5%. The mean distance between the boundaries generated by the proposed algorithm and the corresponding manually delineated boundaries is 2.52 ± 3.54 pixels. Our proposed algorithm assists physicians to determine dental calculus more easily. Doctors no longer need to rely solely on their experiences to recognize dental calculus, but can refer to specific data to assist in diagnosis.

The review provides a concise explanation of principles of operation of different optical coherence tomography methods. A comparative analysis of their advantages and disadvantages is presented in relation to specific applications. The review will assist the reader in making an educated choice on the most suitable optical coherence tomography method to be used in a particular application.

The replacement of classical fillings, especially in the posterior area with different types of inlays has become a common solution used in order to improve all parameters which insure a long lasting treatment. Vrious ceramic materials and systems are available, but so far an ideal ceramic material suited for all clinical situations, has not been found. The range of ceramic materials as: lithium disilicate, aluminum oxide, zirconium oxide and hybrid ceramics enhance the possibilities of using ceramic inalys in various clinical situations. Marginal adaptation is one of the most important conditions for long-term success for any type of material. The marginal discrepancy of fixed restorations is one of the main factors which lead to failure of the prosthetic treatment.The purpose of the present study is to compare a 2D and 3D method for evaluating the marginal fit for pressed lithium dislicate inlays (Emax). The two used methods were: SEM- electronic microscopy and micro CT.

We present a new compact electron gun based on the secondary emission through ionic bombardment principle. The driving parameters to develop such a gun are to obtain a quite small electron gun for an in-flight instrument performing Electron Beam Fluorescence measurements (EBF) on board of a reentry vehicle in the upper atmosphere. These measurements are useful to characterize the gas flow around the vehicle in terms of gas chemical composition, temperatures and velocity of the flow which usually presents thermo-chemical non-equilibrium. Such an instrument can also be employed to characterize the upper atmosphere if placed on another carrier like a balloon. In ground facilities, it appears as a more practical tool to characterize flows in wind tunnel studies or as an alternative to complex electron guns in industrial processes requiring an electron beam. We describe in this paper the gun which has been developed as well as its different features which have been characterized in the laboratory.

The original contribution of the present paper is to present a joint theoretical and experimental approach to implement the modulated absorption/emission technique. Two-dimensional fields of soot temperature and volume fraction can then be measured simultaneously in a reference steady laminar coflow axis-symmetric non-premixed ethylene flame estalished over

The Optical Coherence Tomography (OCT) is an emerging imaging technique with applications in medicine and biomedical optics. OCT is capable of analyzing internal localized microstructures and obtaining high-resolution crosssectional images by backscattered light echo analyze. With resolutions of 1-15 μm, one or two orders of magnitude finer than conventional ultrasound, the OCT is improving the small body imaging techniques. The OCT is mostly a near infrared based analysis technique. The design of OCT systems is based on a Michelson interferometer coupled with a low coherence light source. One arm of the interferometer emits a directed beam scanning the sample. OCT imaging engines usually employ time domain detection using a reference delay arm in order to perform the interferometry. The development of high speed diffraction grating scanners enabled OCT systems to achieve imaging speeds of several thousand axial scans per second and also video rate imaging. A generic OCT system uses...

In PIV particle image blur is usually observed near fluid optical interfaces, i.e. shock waves, and thin flow structure with large density variations, e.g. shear layers and boundary layers. In such an environment the particle image is not only subject to blur, but is also displaced from its actual position due to refraction, which is denoted as optical displacement. In this study particle image blur near a shock wave is investigated in relation to the auto-and cross-correlation map, measurement accuracy and confidence level. The results from a numerical study are supported by PIV measurements of a shock wave in a supersonic wind tunnel. It is demonstrated that particle images are blurred in the direction of lower refractive index (directional blurring). The particle images are also skewed. Therefore particle image blur not only causes correlation peak broadening due to the fact that the particle images increase in size, but more importantly can introduce an asymmetry in the correlation peak and in turn introduce a small bias error in the measured velocity. However, experimental results indicate that particle image blur itself is not the main cause for the increase in measurement uncertainty near shock waves, but that the reduced accuracy can be attributed to the optical displacement. The observation of particle image blur can be used as a detection criterion for a qualitative assessment of the optical displacement. Certain combinations of experimental parameters (viewing angle, f/# and interrogation window size) yield significant errors in the measured velocity. Under certain circumstances optical distortion can become so strong to introduce an unphysical acceleration within the shock wave, visualized as an inflection point with positive slope in the velocity profile across the shock. The study provides some practical suggestions to limit the effect of aero-optical distortion on the velocity measurement.

In PIV particle image blur is usually observed near fluid optical interfaces, i.e. shock waves, and thin flow structure with large density variations, e.g. shear layers and boundary layers. In such an environment the particle image is not only subject to blur, but is also displaced from its actual position due to refraction, which is denoted as optical displacement. In this study particle image blur near a shock wave is investigated in relation to the auto-and cross-correlation map, measurement accuracy and confidence level. The results from a numerical study are supported by PIV measurements of a shock wave in a supersonic wind tunnel. It is demonstrated that particle images are blurred in the direction of lower refractive index (directional blurring). The particle images are also skewed. Therefore particle image blur not only causes correlation peak broadening due to the fact that the particle images increase in size, but more importantly can introduce an asymmetry in the correlation peak and in turn introduce a small bias error in the measured velocity. However, experimental results indicate that particle image blur itself is not the main cause for the increase in measurement uncertainty near shock waves, but that the reduced accuracy can be attributed to the optical displacement. The observation of particle image blur can be used as a detection criterion for a qualitative assessment of the optical displacement. Certain combinations of experimental parameters (viewing angle, f/# and interrogation window size) yield significant errors in the measured velocity. Under certain circumstances optical distortion can become so strong to introduce an unphysical acceleration within the shock wave, visualized as an inflection point with positive slope in the velocity profile across the shock. The study provides some practical suggestions to limit the effect of aero-optical distortion on the velocity measurement.

This paper presents a scanning system that integrates a chromatic confocal displacement sensor for topography measurement of a surface. To take an advantage of its compactness and reliability, an off-the-shelf chromatic confocal displacement sensor is integrated. Instead of moving the sensor, a galvanometer scanner reflects the optical point to increase the scan speed, and fast and accurate scanning motion is realized by learning without a model. The resulting images are corrected based on a geometric model to compensate for image distortion.

The Optical Coherence Tomography (OCT) is an emerging imaging technique with applications in medicine and biomedical optics. OCT is capable of analyzing internal localized microstructures and obtaining high-resolution crosssectional images by backscattered light echo analyze. With resolutions of 1-15 μm, one or two orders of magnitude finer than conventional ultrasound, the OCT is improving the small body imaging techniques. The OCT is mostly a near infrared based analysis technique. The design of OCT systems is based on a Michelson interferometer coupled with a low coherence light source. One arm of the interferometer emits a directed beam scanning the sample. OCT imaging engines usually employ time domain detection using a reference delay arm in order to perform the interferometry. The development of high speed diffraction grating scanners enabled OCT systems to achieve imaging speeds of several thousand axial scans per second and also video rate imaging. A generic OCT system uses...

Gliomas are extremely infiltrative type of brain cancers, the borders of which are difficult to locate. Gliomas largely consist of tumors of astrocytic or oligodendroglial lineage. Usually stereotactic surgery is performed to obtain tumor tissue sample. Complete excision of these tumors with preservation of uninvolved normal areas is important during brain tumor surgeries. The present study was undertaken to explore feasibility of classifying abnormal and normal glioma tissues with Raman spectroscopy (RS). RS is a nondestructive vibrational spectroscopic technique, which provides information about molecular composition, molecular structures and molecular interactions in tissue. Postoperated 33 (20-abnormal and 13-normal) gliomas tissue samples of different grades were collected under clinical supervision. Five micron section from tissue sample was used for confirmatory histopathological diagnosis while the remaining tissue was placed on CaF2 window and spectra were acquired using a ...

Implant treatment is a proven method in dentistry for partial and complete missing teeth reconstruction. In some clinical situations it is advisable to limit the number of implants, which can be obtained by making a bridge connecting the patient’s own tooth with the implant. So far, the possibility of using safe and permanent connections of natural teeth with implants has been examined to a small extent due to the dangers resulting from the different mobility of dental implants and teeth.An attempt was made to use vibro-acoustic techniques to evaluate various combinations of teeth and implants. Pilot studies were carried out on cadavers-pig mandibles with implants. There were recorded sounds in the immediate vicinity of the mandible formed in response to impulse excitations carried out with a point hit against a tooth or implant before and after their joining with a bridge. The comparison of spectra allows to see features indicating a high probability of being able to distinguish be...