Sapphire Window Research Articles

Thermal Image Degradation Through a Heated Sapphire Window

Optical windows are indispensable for monitoring industrial processes under vacuum or high pressure by using thermal imagers and radiation thermometers. When a thermal imager observes a sample through an infrared window at elevated temperatures, the window emits additional thermal radiation and increases the background signal of the thermal images, which results in image degradation. Standard four-bar images with various radiance temperature differences were measured using a thermal imager with a spectral band from 3 μm to 5 μm through a UV-grade sapphire window. The four-bar images are given by a blackbody collimator with various image patterns. The window was indirectly heated in a furnace and then rapidly placed on the optical path between the collimator and the thermal imager. The four-bar image degradation was measured as a function of the window temperature and the radiance temperature difference of the four-bar pattern. A simple equation which describes the contrast of the four-bar image by using the transmittance and reflectance of the sapphire window was proposed. It was confirmed that the model can properly predict the window temperature when the appearance of the four-bar pattern cannot be determined.

Direct measurement technique for shock wave velocity under super high pressure

With the ionization mechanism for the transparent material under the super high pressure, the basic measurement method of shock wave has been analyzed. With the Drude-free electron model, the change in reflectivity of shock wave front under different pressures has been analyzed. The reflectivity of shock wave front for different probe lasers has been compared in theory. And it was found that the reflectivity of shock wave front for 660 nm of probe laser is higher than that for 532 nm. The effect of the detector was found to be caused by the X-ray ionization of the transparent material after analyzing the reflectivity data in space-time scale. From the experiment data, it is found that the beginning of "blank" effect coincides with the start point of laser pulse. The shock wave is later than the "blank" effect under the square laser pulse. In the experiment, the reflectivity of shock wave front is about 40% when the shock velocity is 35 km/s. The theoretical decreasing curve of shock velocity in the sapphire window is confirmed by the experiment data. The formula to calculate the shock wave velocity in the transparent material was deduced and verified.

In situ bubble vesiculation in silicic magmas

Volatile degassing is a major process driving volcanic eruptions. Therefore, a full understanding of mechanisms ranging from bubble nucleation, growth, coalescence, to magma fragmentation is required. We have simulated magma degassing during ascent in the volcanic conduit by depressurizing hydrated haplogranite melts in high-pressure and high-temperature optical cells (a hydrothermal diamond-anvil cell and an internally heated pressure vessel fitted with sapphire windows). This allowed the whole process of bubble nucleation, growth, and coalescence to be directly observed in situ through images captured from the recording videos. Bubble nucleation pressures, number densities, growth laws, and characteristics of coalescence were estimated as a function of melt water content, decompression rate, and temperature. Melt/vapor surface tension during bubble nucleation and coalescence was calculated. Our data show good agreement with those previously obtained in classical vessels. Methodological improvements are proposed for the experimental simulation of magma degassing in volcanic conduits.

High-hydrostatic-pressure optical chamber system for cultivation and microscopic observation of deep-sea organisms

AB Aquatic Biology Contact the journal Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections AB 11:157-162 (2010) - DOI: https://doi.org/10.3354/ab00303 High-hydrostatic-pressure optical chamber system for cultivation and microscopic observation of deep-sea organisms Chengman Bao1, Yun Gai2, Kaikai Lou2, Chunyue Jiang3, Shuming Ye2,* 1College of Life Sciences, Zhejiang University, Hangzhou 310058, PR China 2College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou 310027, PR China 3College of Chemical Engineering and Materials Science, Zhejiang University of Technology, Hangzhou 310014, PR China *Corresponding author. Email: bbccmm_hi@126.com ABSTRACT: We developed and tested a high-pressure optical chamber system for cultivation and microscopic observation of deep-sea organisms. The system is composed of an optical chamber, a high-pressure pump, a pressure sensor and a microscope. The chamber has an observation cavity, 2 cultivation cavities and 2 sapphire windows. The pump is employed for perfusion of culture medium and for increasing the pressure. The pressure sensor monitors the pressure in the chamber. The microscope is used for observing samples through the sapphire windows. In the future, the optical chamber system could be used alone for short-term research or be connected to a large high-pressure vessel to create a flow-through system for long-term research. Using the system, the swimming activity of Bosmina longirostris (Branchiopoda: Cladocera) was observed at different pressures. Swimming activity increased with increasing compression up to 30 MPa. During decompression, this activity reappeared when pressure decreased to 45 MPa and increased with further decreasing pressure. KEY WORDS: Optical chamber system · Real-time · Microscopic observation · Plankton Full text in pdf format PreviousNextCite this article as: Bao C, Gai Y, Lou K, Jiang C, Ye S (2010) High-hydrostatic-pressure optical chamber system for cultivation and microscopic observation of deep-sea organisms. Aquat Biol 11:157-162. https://doi.org/10.3354/ab00303Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AB Vol. 11, No. 2. Online publication date: December 21, 2010 Print ISSN: 1864-7782; Online ISSN: 1864-7790 Copyright © 2010 Inter-Research.

Temperature of a Quartz/Sapphire Window in a Solar Cavity-Receiver

Radiation heat transfer within a high-temperature solar cavity-receiver containing a windowed aperture exposed to concentrated solar radiation is solved using the gray-band approximated radiosity method for semitransparent enclosures. Spectrally selective quartz and sapphire are examined for window materials. Window and cavity temperatures are calculated as a function of the incoming radiative flux and solar energy absorption efficiency. For validation and comparability, a windowless cavity is analyzed. Due to its relatively high reflectance in the visible spectrum, the sapphire window requires higher inlet solar radiative flux than the quartz window to obtain the same reactor temperature and energy absorption efficiency.

Study of Cavity and Output Window for High Power Gyrotron

In this paper Eigen mode analysis has been carried out using Ansoft HFSS for high frequency 42, 120 and 140 GHz Gyrotron cavity. The design of RF window for 42 GHz, 200 kW Gyrotron has also been carried out using the Ansoft HFSS and CST microwave studio. In 42 GHz gyrotron double disc of diameter 85 mm and thickness 3.2 mm sapphire window and spacing (Coolant FC-75) of discs 2.5 mm has been used in the simulation. The return loss (S11) and transmission loss (S21) of the 42 GHz gyrotron window have been found −47.3 and −0.04 dB, respectively. The return loss and transmission loss of the S-band single disc sapphire window have also been found −27.3 and −0.07 dB, respectively at cylindrical waveguide length 33 mm. The simulated result has been validated through experimental results for pill-box S-band sapphire window.

ChemInform Abstract: Deposition of Mass Selected Silver Clusters in Rare Gas Matrices.

We report on the successful ‘‘soft landing’’ of size selected silver dimers and trimers in solid krypton matrices. Silver cluster cations, produced by sputtering, were mass selected in a quadrupole mass filter and then codeposited with krypton on a cooled sapphire or CaF2 window in the presence of low energy electrons. Neutralized cluster samples were interrogated in situ by excitation and fluorescence spectroscopy. Deposition of slow (≤20 eV) silver dimer cations gave rise to strong excitation bands (centered at λ=275 and 390 nm) from Ag2 plus the characteristic triplet signal of the atom. The spectra imply that fewer than 25% of the dimers were fragmented during the neutralization and deposition steps. In similar experiments with Ag3 we were able to assign trimer absorption bands at 331, 364, 402, 421, 458, and 514 nm and identify characteristic emission features at 381, 560, and 626 nm.

Design, fabrication and characterization of a low-temperature co-fired ceramic gaseous bi-propellant microthruster

A gaseous bi-propellant chemical microthruster was developed using low-temperature co-fired ceramic (LTCC) tapes. A sapphire window and silver spark ignition electrodes were successfully co-fired in the LTCC microthruster. Thrust outputs between 0.2 mN and 1.97 mN could be achieved from the 9.9 mm3 thrust chamber by hot-gas operation using ethylene–argon/oxygen mixtures. A non-premixed combustion scheme was utilized by applying an inlet configuration with offset opposing fuel and oxidizer ports. The inlet port design was able to facilitate the generation of swirling flow. Fuel/oxidant mixing could be enhanced in the thrust chamber with the swirling streams according to the cold-flow multi-species 3D computational fluid dynamics (CFD) analysis. Flame chemiluminescence measurements through the transparent observation window were performed to characterize the flame structure in the miniature combustion chamber. The flame zone was found to coincide with the stoichiometric plane predicted by the CFD simulations. Thrust measurements were accomplished by measuring the impingement force of the exhaust jet on a precision balance. The disturbance introduced by the tubing and wiring on the continuous flow microthruster could therefore be eliminated. Thrust was linearly proportional to the total mass flow rate of the inlet. The chemical energy input of the microthruster was approximately 37 W for the maximal measured thrust of 1.97 mN.

A miniaturized carbon dioxide gas sensor based on infrared absorption

A miniaturized sensor for measuring carbon dioxide (CO 2) gas concentration is developed based on infrared absorption. A novel space-double-beam optical probe is designed, which consists of an infrared source, an air chamber, an infrared receiving device, and two sapphire windows. The air chamber is modified by incorporating a parabolic-shaped receiving-light cone to effectively improve the signal-to-noise ratio of the sensor. Four rectangle holes are arranged around the air chamber, and diffusive sampling is adopted to collect gas into the air chamber. The infrared source works between ON and OFF states. The interference of background light is eliminated by subtracting the measured value in the ON state from the OFF state. The measurement model of the sensor is established based on the Lambert–Beer law and the working principle of the sensor. The partial least squares method is applied to calibrate the measurement model. The sensor has a volume of 80 mm ( L)×78 mm ( W)×35 mm ( H), a weight of 200 g, a power consumption of 1.5 W, and a response time of 2.5 s. The experimental results show that the measurement accuracy of the sensor is 0.026% with a measurement range of 0–3% for CO 2 gas concentration.

Characterization of Pad–Wafer Contact and Surface Topography in Chemical Mechanical Planarization Using Laser Confocal Microscopy

In this study, an optical method using laser confocal microscopy was developed to measure the surface contact area and topography of pads under a dry and static condition. A custom-made pad sample holder with a sapphire window and a miniature load cell was used to collect pad surface contact images at controlled loads. By extracting the black spots in the collected images, pad contact area and contact summit density were obtained. The analysis of a post polishing pad sample (8,289×921 µm2) showed that the contact area increased from 0.026 to 0.045% when the pressure increased from 2 to 4 psi and increased further to 0.059% when the pressure increased to 6 psi. The contact summit density also exhibited a linear increase with the applied pressure. The above results were consistent with the Greenwood and Williamson theory, which predicted a linear relationship between pad contact area and contact summit density. Laser confocal microscopy was also used to measure pad surface topography by establishing probability density functions (PDFs) of pad surface height.

Calibration sampling paradox in near infrared spectroscopy: A case study of multi-component powder blend

The objective of this study was to illustrate the sampling paradox resulting from the different strategies of spectral acquisition while preparing and implementing the calibration models for prediction of blend components in multi-component cohesive blends. A D-optimal mixture design was used to create 24 blending runs of the formulation consisting of chlorpheniramine maleate, lactose, microcrystalline cellulose and magnesium stearate. Three strategies: (a) laboratory mixing and static spectral acquisition, (b) IBC mixing and static spectral acquisition and (c) IBC mixing and dynamic spectral acquisition were investigated for obtaining the most relevant and representative calibration samples. An optical head comprising a sapphire window mounted on the lid of the IBC was used for static and dynamic NIR spectral acquisition of the powder blends. For laboratory mixed samples, powders were blended for fixed period of 30 min and later on scanned for NIR spectra. For IBC mixed blends, the spectral acquisition was carried out in-line for 2 min and stopped for static spectral acquisition. The same cycle was repeated for the next 28 min. Partial least square (PLS) calibration models for each component were built and ranked according to their calibration statistics. Optimal calibration models were selected from each strategy for each component and used for in-line prediction of blend components of three independent test runs. Although excellent statistics were obtained for the PLS models from the three strategies, significant discrepancies were observed during prediction of the independent blends in real time. Models built using IBC mixed blends and dynamic spectral acquisition resulted in the most accurate predictions for all the blend components, whereas models prepared using static spectral acquisition (laboratory mixed and IBC) showed erroneous prediction results. The prediction performance differences between the models obtained using the different strategies could be explained in the context of relevancy and representative sample collection at the initial stage of calibration model building.

A Fused α-β “Mini-spectrin” Mimics the Intact Erythrocyte Spectrin Head-to-head Tetramer

Head-to-head assembly of two spectrin heterodimers to form an actin-cross-linking tetramer is a physiologically dynamic interaction that contributes to red cell membrane integrity. Recombinant beta-spectrin C-terminal and alpha-spectrin N-terminal peptides can form tetramer-like univalent complexes, but they cannot evaluate effects of the open-closed dimer interactions or lateral associations of the two-spectrin strands on tetramer formation. In this study we produced and characterized a fused "mini-spectrin dimer" containing the beta-spectrin C-terminal region linked to the alpha-spectrin N-terminal region. This fused mini-spectrin mimics structural and functional properties of intact, full-length dimers and tetramers, including lateral association of the alpha and beta subunits in the dimer and formation of a closed dimer. High performance liquid chromatography gel filtration analyses of this mini-spectrin provide the first direct non-imaging experimental evidence for open and closed spectrin dimers and show that dimer-tetramer-oligomer interconversion is slow at low temperatures and accelerated at 30 degrees C, analogous to full-length spectrin. This protein exhibits wild type dimer-tetramer dissociation constants of approximately 1 mum at 30 degrees C, independent of initial oligomeric state. Conformational states of the mini-spectrin dimer were probed further using chemical cross-linking, which identified distinct groups of cross-links for "open" and "closed" dimers and confirmed the N-terminal region of alpha-spectrin remains highly flexible in the complex, exhibiting closely analogous structures to those observed for the isolated alpha-spectrin N-terminal using NMR (Park, S., Caffrey, M. S., Johnson, M. E., and Fung, L. W. (2003) J. Biol. Chem. 278, 21837-21844). This fusion protein should serve as a useful template for structural and functional studies of the divalent tetramer site.

Raman spectroscopy of triolein under high pressures

This article presents results of the high pressure Raman spectroscopy of triolein. Triolein, a triacylglyceride (TAG) of oleic acid, is an unsaturated fat, present in natural oils such as olive oil. As a basic food component and an energy storage molecule, it has considerable importance for food and fuel industries. To generate pressure in the experiment, we used a high-pressure cylindrical chamber with sapphire windows, presented in (R.M. Siegoczyński, R. Kościesza, D.B. Tefelski, and A. Kos, Molecular collapse – modification of the liquid structure induced by pressure in oleic acid, High Press. Res. 29 (2009), pp. 61–66). Pressure up to 750 MPa was applied. A Raman spectrometer in “macro”-configuration was employed. Raman spectroscopy provides information on changes of vibrational modes related to structural changes of triolein under pressure. Interesting changes in the triglyceride C‒H stretching region at 2650–3100 cm−1 were observed under high-pressures. Changes were also observed in the ester carbonyl (C˭ O) stretching region 1700–1780 cm−1 and the C‒C stretching region at 1050–1150 cm−1. The overall luminescence of the sample decreased under pressure, making it possible to set longer spectrum acquisition time and obtain more details of the spectrum. The registered changes suggest that the high-pressure solid phase of triolein is organized as β-polymorphic, as was reported in (C. Akita, T. Kawaguchi, and F. Kaneko, Structural study on polymorphism of cis–unsaturated triacylglycerol: Triolein, J. Phys. Chem. B 110 (2006), pp. 4346–4353; E. Da Silva and D. Rousseau, Molecular order and thermodynamics of the solid–liquid transition in triglycerides via Raman spectroscopy, Phys. Chem. Chem. Phys. 10 (2008), pp. 4606–4613) (with temperature-induced phase transitions). The research has shown that Raman spectroscopy in TAGs under pressure reveals useful information about its structural changes.

High-pressure optical cell system for online luminescence spectrum research

An optical cell system was developed for online research into the luminescence spectrum under conditions of extremely high hydrostatic pressure up to 60 MPa. The optical cell, which had three 8 mm thick sapphire windows 16 mm in diameter, was mounted directly onto a fluorescence spectrometer. Hydrostatic pressure was achieved through a hand pump and monitored through a pressure sensor. The optical cell system could be used separately. And more importantly, the system could be connected to a high-pressure flowing system for online flowing luminescence measurement. For system validation, fluorescence spectra of Rose Bengal solution using the high-pressure cell were compared with the standard sample holder. Using the system, fluorescence spectra of Rose Bengal dissolved in distilled water were measured under different pressures at room temperature. The fluorescence intensity of Rose Bengal solution changed with pressures, but the peak positions were almost the same.

Scanning SQUID Microscope NDT System Based on Eddy Current Testing

A scanning SQUID microscope based on HTS dc SQUID has been developed. The SQUID is mounted inside the insulation vacuum of a cryostat, which is separated from room temperature samples by a 65 μm thick sapphire window. Operating with a double-D exciting coil, it could be assembled to a scanning SQUID microscope Nondestructive Testing (NDT) system based on eddy current testing. The current is excited by an appropriate sinusoidal alternating (double-D coil) current in the conducting material, and then it induces a corresponding magnetic field. The vertical component of the field is then detected by the scanning SQUID system. The distortion of the field could be detected at the regions of discontinuities, such as flaws. Thereby, the defects inside the materials will be detected with neither contact nor destruction.

Final report on the key comparison CCPR-K2.a-2003: Spectral responsivity in the range of 900 nm to 1600 nm

An international comparison of spectral responsivity in the near infrared region, 900 nm to 1600 nm, designated CCPR-K2.a, has been conducted under the Consultative Committee for Photometry and Radiometry (CCPR) as one of the key comparisons to support the Mutual Recognition Arrangement (MRA). This comparison was participated in by 15 laboratories and was piloted by National Institute of Standards and Technology (NIST). The comparison was carried out through calibration of a group of transfer standard detectors, which were indium gallium arsenide (InGaAs) photodiodes with sapphire windows, mounted with a thermistor. The comparison was organized in a star pattern, and conducted in four groups of participants. The report describes in detail the measurements made at NIST and summarizes the reports submitted by the participants. Key comparison reference values and degrees of equivalence have been determined from the comparison results.Main text.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCPR, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Influence of impurities on the α to ω phase transition in zirconium under dynamic loading conditions

Experiments have been carried out to investigate the α to ω phase transition in polycrystalline zirconium (Zr) metal. Samples with three levels of impurities were shock loaded using both gas-driven and powder-driven guns and ramp loaded using magnetic drive to investigate the effects of impurities on the properties of this solid-solid phase transition. Samples were backed by either sapphire or LiF windows and data were obtained using a VISAR to record the particle velocity at the sample/window interface. The results of these experiments showed significant differences in both the transition stress and kinetics for samples with different impurity levels demonstrating that impurities play an important role in the transformation mechanism in zirconium.

In-line quantification of drug and excipients in cohesive powder blends by near infrared spectroscopy

This work was aimed at investigating the utility of near infrared (NIR) spectroscopy for simultaneous in-line quantification of drug and excipients in cohesive powder blends in a bin blender. A model formulation containing micronized chlorpheniramine maleate (μCPM), lactose, microcrystalline cellulose (MCC) and magnesium stearate (MgSt) was selected for the blending study. An optical head comprising a sapphire window mounted on the lid of the bin was used to collect in-line NIR spectral data of the powder blends. Validated partial least square (PLS) calibration models were used to quantify each component from the NIR spectra of the blends. Additionally, effects of premixing by sieving and high shear mixing and use of an internal prism fixed within the bin on the mixing performance of each component were studied. The statistical results obtained for PLS calibration models and their validation showed the sensitivity of NIR for accurate quantification of blend components. The blend prepared with high shear premixing and with prism achieved uniformity more rapidly than that with high shear premixing but without prism during blending in a bin blender. Premixing using sieving proved to be inadequate for uniform mixing of the blend components as none of the components except MgSt achieved uniform distribution after the preset blending time when blended in the bin blender. This study demonstrated that by high speed sampling and rapid spectral acquisition, distribution of individual blend components can be assessed with high accuracy during blending. Furthermore, high shear premixing facilitated rapid distribution and uniformity achievement of blend components. This technique may be used to monitor the relative distribution of individual blend components in real time and thus, to assess the performance of a bin blender for mixing of cohesive multi-component powder blends during development and production.

Heterodimerization of the Sialidase NEU1 with the Chaperone Protective Protein/Cathepsin A Prevents Its Premature Oligomerization

Lysosomal neuraminidase-1 (NEU1) forms a multienzyme complex with beta-galactosidase and protective protein/cathepsin A (PPCA). Because of its association with PPCA, which acts as a molecular chaperone, NEU1 is transported to the lysosomal compartment, catalytically activated, and stabilized. However, the mode(s) of association between these two proteins both en route to the lysosome and in the multienzyme complex has remained elusive. Here, we have analyzed the hydrodynamic properties of PPCA, NEU1, and a complex of the two proteins and identified multiple binding sites on both proteins. One of these sites on NEU1 that is involved in binding to PPCA can also bind to other NEU1 molecules, albeit with lower affinity. Therefore, in the absence of PPCA, as in the lysosomal storage disease galactosialidosis, NEU1 self-associates into chain-like oligomers. Binding of PPCA can reverse self-association of NEU1 by causing the disassembly of NEU1-oligomers and the formation of a PPCA-NEU1 heterodimeric complex. The identification of binding sites between the two proteins allowed us to create innovative structural models of the NEU1 oligomer and the PPCA-NEU1 heterodimeric complex. The proposed mechanism of interaction between NEU1 and its accessory protein PPCA provides a rationale for the secondary deficiency of NEU1 in galactosialidosis.

Microscopic phase behavior of supercritical carbon dioxide + non-ionic surfactant + water systems at elevated pressures

The microscopic phase behavior of the supercritical carbon dioxide (scCO 2) + polyethylene oxide-2,6,8-trimethyl-4-nonyl ether (TMN) + water systems at about 3 wt% of TMN were investigated using a synthetic method with a microscope. The two types of TMN (TMN-3 and TMN-10) used in this work had molecular weight distributions caused by the distribution of the number of ethylene oxide groups. Two different types of phase transition were observed when pressure was decreased gradually at a constant temperature from the high pressure at which the transparent phase was observed to the low pressure at which the separate vapor–liquid phases were observed for the scCO 2 + TMN-3 + water system at 3 wt% of TMN-3. The transparent phase was colorless under all experimental conditions and the phase transition from a transparent phase to a turbidity phase with small, dispersed droplets was observed at the higher side phase transition (higher phase transition pressure). As the pressure continued to decrease, another phase transition was observed from the phase with small droplets to a state with an accelerating aggregation of droplets (lower phase transition pressure). In the turbidity phase between the higher and the lower phase transition, the degree of turbidity became higher with decreasing pressure. On the other hand, in the phase observed below the lower phase transition, a new liquid phase adhered to the sapphire windows and the wall inside the optical cell. The effect of water concentration on the phase transition pressures for the scCO 2 + TMN-3 + water system was investigated from the results at 1 wt% and 3 wt% of TMN-3. The higher phase transition pressures at 3 wt% of TMN-3 were lower than those at 1 wt%, as measured in our previous work. Moreover, the minimal values of the higher phase transition pressure were observed for the system at 3 wt% of TMN-3 as well as those at 1 wt%. The lower phase transition pressures of the scCO 2 + TMN-3 + water system at 3 wt% of TMN-3 decreased as the water concentration increased to about 1 wt%, and the lower phase transition pressures stayed constant in the range of water concentration from about 1 to 3.62 wt%. On the other hand, the homogeneous phase was not established at water concentrations higher than about 3.86 wt%. As for the scCO 2 + TMN-10 + water system, a transparent homogeneous phase could not be observed in the range of the investigation at 3 wt% of TMN-10.