Glass Disk Research Articles

Highly efficient azo dye degradation in a photocatalytic rotating disc reactor with deposited l-histidine-TiO2-CdS

In the past few years, the quest for visible light active TiO2-based photocatalysts has been a hotly debated research topic in both scientific and practical fields. Attempting to meet the same purpose, in this study, a visible-driven nanocomposite, l-Histidine (2 wt%)-TiO2-CdS (7:1) nanocomposite, was dip-coated on the glass disc (rough vs. smooth) after the optimum composition was identified by varying the l-Histidine and CdS quantities. The prepared nanoparticles and coated catalyst on the disc were characterized by XRD, FT-IR, X-ray (FE-SEM/EDX), DRS, PL analyses in terms of their structural and optical properties as well as morphology. The coated photocatalyst was tested for photocatalytic degradation of direct red 16 (DR16) as an azo dye. The photodegradation process variables, including disc rotation speed, light intensity, irradiation time, and type of disc (smooth vs. rough glass disc)) were also modeled and optimized by central composite design (CCD). At the optimum conditions obtained, the effects of reaction time, pH, DR16 concentration, and aeration were investigated. After 3 h of using the rough disc (disc II) at a disc rotation speed of 100 rpm as well as a light intensity of 13 lumens per m2, DR16 was completely degraded. The pH and DR16 concentration seemed to have the reverse impact on the photodegradation process, whereas aeration had such a positive effect. By analyzing the effects of various scavengers, the contribution of reactive species in the photodegradation process was thoroughly investigated. Furthermore, the reusability results indicate no significant change in the photodegradation efficiency after four cycles.

High-power near-CW Raman lasing in mm-sized glass disks

We experimentally demonstrate Raman lasing in a mm-sized CaF2 disk, with an optical power output of the first Stokes sideband exceeding 100 mW in a near-continuous wave (CW) operation. The pump beam at a wavelength of 1.06 μ m is coupled to the whispering gallery modes of the disk with the use of a tapered glass fiber. With the pump beam coupled to one of the resonator modes, we observe the generation of the first and the second Stokes sidebands at wavelengths of 1.1 μ m and 1.14 μ m, respectively. The conversion efficiency from the pump laser beam to the generated sidebands is ∼10%. These results open up the prospect of using such mm-sized disks as compact, highly efficient ultrafast modulators with modulation frequencies as high as 10 THz.

Modeling and validation of eccentricity effects in fine angle signals of high precision angular sensors

High precision optical angular sensors are extensively used for detection and control of position and velocity in payload rotating mechanisms and spacecraft actuators. The accuracy and thus the performance of the encoder are significantly affected due to installation eccentricity. In this paper, a comprehensive study of the causes of installation eccentricity is done. The apportionment of the resultant eccentricity is attributed to variations in diametrical clearances, doweling error, gluing error of the glass disc and bearing wobble. The effect of eccentricity changes during rotation. A new 3-center variable eccentricity model is introduced which improves upon the existing 2-centered one in previous literature. This new 3-centered model is able to better predict the deviations in the fine angle signals in a practical system due to variable eccentricity effect. The efficacy of the mathematical model was validated through two independent experiments- 1) by analyzing the electrical signals from opposite read-heads and 2) by performing mechanical measurements- both done on an actual sensor assembly. The eccentricity value calculated from the maximum and minimum phase difference of the fine angle signals is able to exactly match with the total phase difference variation over one complete rotation. It is observed that the variation in the phase difference between the fine angle sinusoidal signals given by two opposite read-heads varies as a shifted sine over one complete rotation and not as a symmetric sine as shown in previous literature. The eccentricity value obtained from mechanical measurement and that computed using the 3-centered model was matching within 0.1 µm. Both the experimental results support the effectiveness of the 3-centered model.

Review on development of wet latent fingerprints by small particle reagent

Small particle reagent technique is a method which is used to develop fingermarks on moist and smooth surfaces. It consist the theory of adherence of fine particles which is suspended in a treating solution to the oily or fatty components (water insoluble) present in in latent fingermark residue and gives a grey colored deposit. It is also considered as belonging to the family of powder dusting. The effectiveness of this technique can be increased by using fluorescent dyes in it's treating solution which can also detect faint fingermarks on multi-colored surfaces. Small particle reagent involves the use of synthetic detergent which was here replaced by saponin extracted from the fruit of Sapindus mukorossi as natural detergent. The other ingredient used in the formulation is black charcoal powder. This composition develops sharp and clear fingermarks on non-adsorbent surfaces like glass, metal sheet, plastic, laminated wood, ceramic tiles and compact discs after these were immersed in water for variable periods of time. The ability of the present formulation to detect weak chance prints not only enhances its utility, but also its potentiality in forensic investigations. The raw materials used to prepare the SPR are easily available and cost-effective.

Comparison of polymerization stresses of dental resin composites evaluated by two indentation fracture methods.

Polymerization stress is a major problem in dental resin composite restorations. Two indentation fracture methods can be applied to evaluate the stress, however, they often calculate different values. To compare polymerization stresses of dental composites determined by the two methods. Glass disks with a central hole were used. Two indentation fracture methods (Methods1 and2) were employed to determine the polymerization stresses of low-shrinkage and bulk-fill composites. Method1: Cracks were made in the glass surface at 300μm from the hole. The hole was filled with the composite. Polymerization stresses at 30min after filling were calculated from the lengths of crack extension. Method2: The hole was filled with the composite. Cracks were introduced in the glass at 1,000μm from the hole at 30min after the polymerization and the stresses were calculated from the crack lengths. Stresses at composite-glass bonded interface were calculated from the stress values obtained by the two methods. The bulk-fill composite generated the smallest interfacial stress, and Method1 revealed lower values than Method2. The composites yielded relatively small stresses. Method1 calculated smaller stress values, possibly affected by the lower threshold stress intensity factor.

Thermal Effects in Slender EHL Contacts

This study deals with experimental and numerical analysis of the thermal effects of slender elastohydrodynamically lubricated (EHL) contacts under high sliding. Thereby, the entrainment direction is along the major axis of the contact ellipse. Film thickness measurements were carried out on an optical EHL tribometer with a glass disk and steel roller. Numerical EHL solutions were obtained with consideration for non-Newtonian rheology and thermal effects. The results show that thermal effects can result in a strong viscosity wedge diverting oil flow to the contact sides. For high positive sliding, in which the glass disk moves faster, the influence of entrainment speed on minimum film thickness is almost negligible, while the film thickness shows a continuous decrease in gap length direction.

Quantitative verification of 1:35 diluted fused glass disks with 10 mg sample sizes for the wavelength-dispersive X-ray fluorescence analysis of the whole-rock major elements of precious geological specimens

Herein, an improved wavelength-dispersive X-ray fluorescence (WD-XRF) analytical technique for determining the major elements (including SiO2, TiO2, Al2O3, TFe2O3, MnO, MgO, CaO, Na2O, K2O, and P2O5) in precious geological samples, particularly extraterrestrial basaltic rock samples, was developed. For WD-XRF analysis, undersized (approximately 11 mm in diameter) glass disks were prepared by fusing 10 mg of a powdered sample with 350 mg of lithium borate flux at a sample-to-flux ratio of 1:35. Specialized PtAu crucibles and molds were crafted for glass disk preparation to facilitate automatic fluxer mounting. This procedure enabled the automatic preparation of undersized glass disks, with repeatability between sample batches. Calibration curves were constructed for 30 certified reference materials (CRMs), including felsic, intermediate, mafic, and ultramafic igneous rocks. Regular-sized CRM disks with large sample sizes were prepared at the same sample-to-flux ratio as the test samples to avoid issues caused by CRM heterogeneity. The influence of various factors, including glass disk thickness and homogeneity, releasing agent amount, and interference between lines (Br Lα with Al Kα, Rh Lγ2 and Rh Lγ3 with K Kα, and K Kβ with Ca Kα), on analytical accuracy was investigated. Two homogeneous synthetic reference glass samples (ARM-2 and ARM-3) were pulverized and used to verify the analytical results for small samples using the WD-XRF method, which could eliminate the uncertainty caused by sample homogeneity. Subsequently, three CRMs (JB-1b, JA-3, and JR-1) were used to validate the accuracy and precision of the method. Finally, two lunar meteorite samples (NWA4898 and NWA4734) were assayed by the proposed method, and comparison with inductively coupled plasma optical emission spectroscopy results confirmed the reliability of the method. The proposed small sample protocol, which involves the destructive pretreatment of precious and limited extraterrestrial basaltic samples, has great application potential for precious samples such as lunar soil samples.

Highlights from 25 Years of the GeoPT Programme: What Can be Learnt for the Advancement of Geoanalysis

Data submitted over the past 25 years to GeoPT, the highly successful proficiency‐testing programme for the geochemical analysis of geological materials, organised by the International Association of Geoanalysts, provide a valuable resource that permits detailed investigation of contrasting results associated with different sample preparation and measurement principles. Highlighted issues include the following: recurring problems with the dissolution of the refractory minerals zircon and chromite, which produce a large dispersion in data obtained when acid digestion is involved; issues related to different XRF sample preparation methods, whereby a significant divergence of pressed powder pellet results compared with those from fused glass discs is observed; high relative dispersion of data both at low mass fractions, and those higher than normally found in silicate rocks, due to incomplete method validation, in particular due to an overconfidence in estimating reporting limits and to the employment of limited working ranges. In addition, an example for Sr in an ancient pegmatite with extremely high Rb abundance is presented, where ICP‐MS results amount to only to a third of the XRF results, severely underestimated due to the disregard of the radiogenic ingrowth from 87Rb decay. Recommendations are made both for improving data quality and the selection of test materials for future GeoPT rounds.

Effects of solid viscoelasticity on elastohydrodynamic lubrication of point contacts

Dry and lubricated highly deformed contacts appear in engineering, physics, and bio-(fluid)mechanics, with increasingly many applications where the soft materials can exhibit viscoelastic behaviour. In this work, the viscoelastic solid lubricated point contact problem has been studied theoretically and experimentally. An efficient visco-elastohydrodynamic lubrication (VEHL) numerical algorithm has been developed by implementing a novel viscoelastic deformation equation. The relevant dimensionless parameters of the VEHL problem are identified and a parameter study is presented showing the effect of solid viscoelasticy on the pressure and film thickness in the conjunction. In addition experimental results are presented for film thickness measurements in configurations of a PMMA ball rolling against a glass disc, and a steel ball rolling against a glass disc using optical interferometry. Finally the scaling of the pressure and film profiles in the inlet and outlet regions to the contact have been studied, investigating self similarity of the pressure and film solution in these regions. The results presented provide a good framework for the understanding and interpretation of viscoelastic solid effects on the film and pressure behavior in highly deformed (soft) lubricated contacts.

Study on Filling Capacity of Optical Glass in a Novel Rapid Hot Embossing Process

This paper aims to present a novel rapid hot embossing approach and to study filling capacity of optical glass in the hot embossing process. Firstly, a novel rapid hot embossing device is developed, which consists of a rapid heating module and a precision loading module. Particularly, the rapid heating module allows a maximum temperature of 800 °C and a heating rate of 300 °C/min, with decent temperature control accuracy and uniform temperature distribution. In hot embossing process, by incompletely filling the microhole of silicon carbide mold, a microlens would be formed on the surface of glass disc, and the filling capacity of glass is quantified by the maximum height of the microlens. The tailor-made hot embossing device was exploited to conduct a series of experiments for evaluating effects of process parameters on the filling capacity of N-BK7 glass. Experimental results indicate that the filling capacity of glass could be enhanced by increasing the embossing force, the embossing temperature, the soaking time but decreasing the annealing rate. Furthermore, compared to soaking time and annealing rate, embossing force and embossing temperature have more significant influence on the filling capacity of N-BK7 glass. Therefore, the novel rapid hot embossing is a practical and promising technology for fabricating microstructures on glass materials with high softening points.

Fabrication of Glass Diaphragm Based Fiber-Optic Microphone for Sensitive Detection of Airborne and Waterborne Sounds.

A glass-diaphragm microphone was developed based on fiber-optic Fabry-Perot (FP) interferometry. The glass diaphragm was shaped into a wheel-like structure on a 150-μm-thick glass sheet by laser cutting, which consists of a glass disc connected to an outer glass ring by four identical glass beams. Such a structural diaphragm offers the microphone an open air chamber that reduces air damping and increases sensitivity and results in a cardioid direction pattern for the microphone response. The prepared microphone operates at 1550 nm wavelength, showing high stability in a range of temperature from 10 to 40 °C. The microphone has a resonance peak at 1152 Hz with a quality factor of 21, and its 3-dB cut-off frequency is 32 Hz. At normal incidence of 500 Hz sound, the pressure sensitivity of the microphone is 755 mV/Pa and the corresponding minimum detectable pressure is 251 μPa/Hz1/2. In addition to the above characteristics of the microphone in air, a preliminary investigation reveals that the microphone can also work stably under water for a long time due to the combination of the open-chamber and fiber-optic structures, and it has a large signal-to-noise ratio in response to waterborne sounds. The microphone prepared in this work is simple, inexpensive, and electromagnetically robust, showing great potential for low-frequency acoustic detection in air and under water.

Preparation and properties of a high-entropy amorphous oxide with high refractive index by containerless solidification

A non-proportional high-entropy oxide glass disc: 25LaO3/2-25TiO2–25NbO5/2-(25-x) WO3-xZrO2(x = 0, 5, 10) was formed using containerless solidification technology. In optical tests, the 25LaO3/2-25TiO2–25NbO5/2-20WO3–5ZrO2(x = 5) disc had the highest refractive index (2.53) and the highest visible transmittance (84%). In addition, the refractive index of amorphous materials prepared from La2O3, TiO2, Nb2O5, WO3, and ZrO2 were all greater than 2.1, which is considered as a high refractive index. The results suggest that these components can provide a specific reference for optical glass material selection in future research.Furthermore, based on the concept of performance synergy in high-entropy materials, our research group developed a high-entropy amorphous oxide in equal proportion, 20LaO3/2-20TiO2–20NbO5/2-20WO3–20ZrO2 (Qi Xiwei, 2019). The structure has a high refractive index (2.22) and a high Abbe coefficient (61), which ensures that the lens has sufficient clarity when it is ultra-thin. By comparing the results of the two systems, we found that all non-proportional high-entropy systems are unable to simultaneously show both a high Abbe value and a high refractive index. This phenomenon further indicates the necessity of preparing high-entropy amorphous oxide in equal proportion.

Monolithic edge-cladding process for the elliptical disk of N31-type Nd-doped high-power laser glass

Abstract This paper investigates the monolithic edge-cladding process for the elliptical disk of N31-type Nd-doped phosphate laser glass, which will be utilized under liquid cooling conditions for high-power laser systems. The thermal stress, interface bubbles and residual reflectivity, which are due to high-temperature casting and bonding during the monolithic edge-cladding process, are simulated and determined. The applied mould is optimized to a rectangular cavity mould, and the casting temperature is optimized to 1000°C. The resulting lower bubble density makes the mean residual reflectivity as low as 6.75 × 10−5, which is enough to suppress the amplified spontaneous emission generated in the Nd-glass disk, and the resulting maximum optical retardation is converged to 10.2–13.3 nm/cm, which is a favourable base for fine annealing to achieve the stress specification of less than or equal to 5 nm/cm. After fine annealing at the optimized 520°C, the maximum optical retardation is as low as 4.8 nm/cm, and the minimum transmitted wavefront peak-to-valley value is 0.222 wavelength (632.8 nm). An N31 elliptical disk with the size of 194 mm × 102 mm × 40 mm can be successfully cladded by the optimized monolithic edge-cladding process, whose edge-cladded disk with the size of 200 mm × 108 mm × 40 mm can achieve laser gain one-third higher than that of an N21-type disk of the same size.

INVESTIGATION OF THE INTERACTION OF LEAD-SILICATE GLASSES WITH BARIUM HYDROXIDE

The effect of alkaline treatment on the destruction process and some surface characteristics of mechanically processed glass discs of lead-silicate glasses C87-2 and C78-4 has been studied. It is shown that the interaction of these glasses with barium hydroxide leads to the removal of silicic acid from the gel surface, which in turn improves the water wettability and optical transparency of the glasses. It is proposed in the production technology of electric vacuum devices, where lead-silicate glasses are used, to use washing with barite water for rapid coagulation of silica gel, which eliminates the appearance of foreign particles on the surface of the glasses.

Production of microplastics by using textured glass surface

The increase of plastic waste disposed in the environment is a great concern. It is known that these plastic products are fragmented smaller pieces resulting the microplastics (MPs) are generated. In order to study the effects of MPs on living organisms and human immune system, it is necessary to provide MPs for biological tests guaranteed the morphology and size. This study aimed to adjust the geometric shape of MPs by using MP manufacturing systems for environmental fragmentation mechanisms. The proposed system was a pin-on-disc machine with multi-directional sliding motions. Pin made of plastic material was pressed onto a quartz glass disc under the lubrication of artificial sea water. Three types of microtextured glass were prepared and used for elucidating the influence of MP generation. The wear modes of polymer seemed to be affected by convex structures on glass and the material properties of polymer. For the pin made of PVC, which is an amorphous plastic, the production of MPs increased by a larger diameter of the convex structures. The larger diameter increased apparent contact area between the pin and disc, so adhesive wear mode might be predominant. For the pin made of PE, PP and PET, which is crystalline plastic, the production of MPs increased by a larger pitch of the convex structures. The larger pitch enhanced the plastic deformation of plastic into a valley structure, so that fatigue wear might be predominant.

Ultrasonic control of neurite outgrowth direction

This study investigated a method to control neurite outgrowth direction using ultrasound vibration. An ultrasound cell culture dish comprising a glass-bottom culture surface and a glass disc with an ultrasound transducer was fabricated, and undifferentiated neuron-like PC12 cells were grown on the dish as an adherent culture. The 78 kHz resonant concentric flexural vibration mode of the dish was used to quantitatively evaluate the neurite outgrowth direction and length. Time-lapse imaging of cells was performed for 72 h under ultrasound excitation. Unsonicated neurites grew in random directions, whereas neurite outgrowth was circumferentially oriented during ultrasonication in a power-dependent manner. The neurite orientation correlated with the spatial gradient of the ultrasound vibration, implying that neurites tend to grow in directions along which the vibrational amplitude does not change. Ultrasonication with 30 Vpp for 72 h increased the neurite length by 99.7% compared with that observed in unsonicated cells.

Novel method for selecting slices of the same cross-sectional view from digital tomosynthesis for monitoring posterior spinal instrumentation

BackgroundA method to evaluate pedicle screw loosening on digital tomosynthesis images is yet to be established owing to lack of methods for selecting slices of the same cross-sectional view. We aimed to develop an objective method for selecting slices of the same cross-sectional view on digital tomosynthesis images. MethodsFirst, an objective method of pixel selection was developed by measuring the size of glass disk and titanium alloy screw on digital tomosynthesis images followed by comparison with the actual sizes. Second, a method for selecting slices of the same cross-sectional view was explored on a bone model with posterior spinal instrumentation using the screw centerline and rod curvature as indicators of the same cross section. The angle between the screw centerline and rod was calculated to verify the accuracy in obtaining the same cross-sectional view. Third, the method for selecting slices of the same cross-sectional view was applied to six patients after posterior lumbar spinal instrumentation. ResultsThe pixel selection method enabled objective determination of a pixel on the peripheral lines of objects with an error as low as 200 μm in distance measurements on titanium alloy and glass. The mean differences of rod-screw angles between two slices were less than 1° and were not statistically significant in the bone model and patient images. ConclusionA method for selecting slices of the same cross-sectional view on digital tomosynthesis images was successfully developed. This method can enable objective and quantitative evaluations of pedicle screw loosening.

Influence of the Heat Transfer Field on Anomalous Lubricant Film Formation in Elastohydrodynamic Lubrication Conditions

The influence of the heat transfer field on anomalous film formation under elastohydrodynamic lubrication (EHL) conditions was studied. Liquid lubricant film shapes between a transparent disc and steel ball friction pair were investigated by white light optical interferometry. The fatty alcohol 1-dodecanol was used as the representative lubricant to develop anomalous film shapes. A sapphire disc and glass disc, which have different thermal conductivities, were used as the transparent bounding surface. Experiments were performed wherein the applied load, sliding conditions and ambient temperature were varied. The temperature of the lubricant film was estimated by a simple model with the measured traction coefficient. The estimated temperature and maximum Hertzian pressure were compared with the phase diagram of 1-dodecanol obtained using a diamond anvil cell to investigate the phase state of the lubricant film. It was found that the anomalous film shape was stably formed in the solid-state regime of the phase diagram whereas the film exhibited unique characteristics such as the collapse behaviour in high sliding conditions and liquid-like behaviour of the traction with a remaining thickened film part in the liquid state regime.

A simple and rapid method to simultaneously analyze ciclesonide and its impurities in a ciclesonide metered-dose inhaler using on-line supercritical fluid extraction/supercritical fluid chromatography/quadrupole time-of-flight mass spectrometry

A simple and rapid on-line SFE/SFC/quadrupole TOF-MS method to simultaneously analyze active pharmaceutical ingredients and impurities from metered-dose inhalers (MDIs) was developed using ciclesonide MDI (CIC-MDI) as an example. CIC-MDI, as drug Alvesco®, has been approved for the treatment of bronchial asthma, and its major impurities are listed in the European Pharmacopoeia and in the supplementary package inserts of Alvesco® (called as “Pharmaceutical interview form” in Japan). In the developed method, CIC-MDI was manually sprayed only once on a glass disc prior to the SFE/SFC/quadrupole TOF-MS. In the SFE, CIC and its impurities and other impurities having various polarities and hydrophobicity, were extracted in 3.5 min and subsequently separated on a CHIRALPAK IE-3 column to be detected by quadrupole TOF-MS in 6.5 min. This method would be applicable to the analysis of other inhalable pharmaceutical products whose sample preparation requires complicated procedures, as well as to the analysis of general pharmaceutical products for profiling impurities.

Varifocal optical lens using ultrasonic vibration and thixotropic gel.

A variable focus optical lens using a thixotropic gel and ultrasonic vibration is discussed. The surface profile of the gel could be deformed via acoustic radiation force generated by ultrasound. A thixotropic gel in which the viscosity was changed by shear stress was employed as a transparent lens material. The thixotropic gel allowed the lens to maintain shape deformation in the absence of continuous ultrasound excitation. The lens had a simple structure with no mechanical moving parts and included an annular piezoelectric transducer, a glass disk, and the thixotropic gel film. The axisymmetric concentric flexural vibration mode was generated on the lens at 71 kHz, which resulted in static surface deformation of the gel via the acoustic radiation force. The preservation rate was investigated after switching off the ultrasonic excitation. There was a trade-off between the preservation rate of the lens deformation and the response time for focusing. The focal length could be controlled via the input voltage to the lens, and a variable-focus convex lens could be realized; the change in the focal length with 4.0 Vpp was 0.54 mm. The optical transmittance of the lens was measured and the transmittance ranged 70%-80% in the visible spectral region.