Glass Block Research Articles

Monolithic optofluidic ring resonator lasers created by femtosecond laser nanofabrication.

We designed, fabricated, and characterized a monolithically integrated optofluidic ring resonator laser that is mechanically, thermally, and chemically robust. The entire device, including the ring resonator channel and sample delivery microfluidics, was created in a block of fused-silica glass using a 3-dimensional femtosecond laser writing process. The gain medium, composed of Rhodamine 6G (R6G) dissolved in quinoline, was flowed through the ring resonator. Lasing was achieved at a pump threshold of approximately 15 μJ mm(-2). Detailed analysis shows that the Q-factor of the optofluidic ring resonator is 3.3 × 10(4), which is limited by both solvent absorption and scattering loss. In particular, a Q-factor resulting from the scattering loss can be as high as 4.2 × 10(4), suggesting the feasibility of using a femtosecond laser to create high quality optical cavities.

Research and Development of Overloading Velocity Jump Line Contact Elastohydrodynamic Lubrication Testbed

To research the lubricating property of line contact elastohydrodynamic lubrication under the working conditions of overloading velocity jump, based on the optic elastohydrodynamic experimental apparatus developed by the research group, an measuring equipment applicable to the oil film thickness and shape under the condition of overloading velocity jump is designed and developed. This testbed is mainly composed of glass block reciprocating motion system, ball or roller rotary rolling system, loading system, speed regulating system, light source system and image acquisition system. The motion part replaces the slider-crank mechanism with kad-screw mechanism and is driven by stepper motor, so as to realize the different working conditions of velocity jump. The developed platform was adopted to carry out the velocity jump line contact elastohydrodynamic lubrication test by the driving of the stepping motor, investigating the influence of line contact friction pair on the lubricating oil film at the moment of acceleration under the overloading working condition.

Porous glass membranes with an aligned pore system via stretch forming in combination with thermally induced phase separation

In this study, we report about a stretching process coupled with the phase separation of alkali-borosilicate glasses to produce porous glasses with different degrees of pore alignment. For this purpose two different initial glasses with the composition (wt %): 62.5SiO2 · 30.5B2O3 · 7Na2O and respectively 70SiO2 · 23B2O3 · 7Na2O were molten at 1500°C for 3 h and solidified in a casting mold. The resulting glass blocks were cut into thin plates with appropriate dimensions. These slides were clamped into a glass-stretching apparatus in which deformation and phase separation could occur simultaneously. The glass plates were stretched until breaking, thus having different elongation periods, i. e. phase separation periods. Different temperatures and tensile loads have been applied, thus having two independent parameters to influence the time until fracture. The elongated parts of the samples were cut off and underwent an acid and an alkaline treatment to remove the soluble components. The pore size distribution, the specific surface area and the microstructure of selected samples have been determined by mercury intrusion, nitrogen sorption and environmental scanning electron microscopy, respectively. Mercury intrusion porosimetry showed porosities up to 60% with pore sizes in the 100 nm range. The results were compared to those obtained for undeformed samples treated at comparable temperatures and times.

Development of Testing Machine for Measuring Unsteady State EHL Film under Heavy Load

In order to study elastohydrodynamic lubrication characteristics of cylindrical roller under heavy load and unsteady state, a testing machine is designed for measuring line contact film thickness and shape according to optical interference principle. The experimental apparatus is mainly made of glass block reciprocating motion systems, ball or roller rolling rotation system, loading system, speed control systems, lighting systems and image acquisition system. Moving parts is formed by the slider-crank mechanism. Specimen is accompanied by a pair of floating trial roller bearing. Specimen load is applied by leverage. The entrainment velocity of roller is approximate sinusoidal variation during a cycle. Experiment interference image is satisfactory, can provide reliable experimental data for future research.

Studies of the reflection, refraction and internal reflection of light

An inexpensive apparatus and associated experiments are described for studying the basic laws of reflection and refraction of light at an air–glass interface, and multiple internal reflections within a glass block. In order to motivate students and encourage their active participation, a novel technique is described for determining the refractive index of a block of glass by observing multiple internal reflections. With a similar intention, the paper also includes a number of guidance notes for instructors.

Photoprotection: clothing and glass.

Ultraviolet (UV) radiation (UVR) has well-known adverse effects on the skin and eyes. Little attention is given to physical means of photoprotection, namely glass, window films, sunglasses, and clothing. In general, all types of glass block UV-B. For UV-A, the degree of transmission depends on the type, thickness, and color of the glass. Adding window films to glass can greatly decrease the transmission of UV-A. Factors that can affect the transmission of UVR through cloth include tightness of weave, thickness, weight, type of fabrics, laundering, hydration, stretch, fabric processing, UV absorbers, color, and fabric-to-skin distance.

SU-E-T-186: Feasibility Study of Glass Cherenkov Detector for Prompt Gamma Detection in Proton Therapy

Purpose: To simulate a Cherenkov glass detector system utilizing prompt gamma (PG) technique to quantify range uncertainties in proton radiation therapy. Methods: A simulation of high energy photons typically produced in proton interactions with materials incident onto a block of Cherenkov glass was performed with the Geant4 toolkit. The standard electromagnetic package was used along with several decay modules (G4Decay, G4DecayPhysics, and G4RadioactiveDecayPhysics) and the optical photon components (G4OpticalPhysics). Our setup included a pencil beam consisting of a hundred thousand 6 MeV photons (approximately the deexcitation energy released from 16O) incident onto a 2.5 ⊗ 2.5 ⊗ 1.5 cm3 of a Cherenkov glass (7.2 g of In2O3 + 90 g cladding, density of 2.82 g/cm3, Zeff = 33.7, index of refraction 1.56). The energy deposited from incident 6 MeV photons as well as secondary electrons and resulting optical photons were recorded. Results: The energy deposited by 6 MeV photons in glass material showed several peaks that included the photoelectric, the single and double escape peaks. About 11% of incident photons interacted with glass material to deposit energy. Most of the photons collected were in the region of double escape peak (approximately 4.98 MeV). The secondary electron spectrum produced from incidentmore » photons showed a high energy peak located near 6 MeV and a sharp peak located ∼120 keV with a continuous distribution between these two points. The resulting Cherenkov photons produced showed a continuous energy distribution between 2 and 5 eV with a slight increase in yield beginning about 3 eV. The amount of Cherenkov photons produced per interacting incident 6 MeV photon was ∼240.7. Conclusion: This study suggests the viability of utilizing the Cherenkov glass material as a possible prompt gamma photon detection device. Future work will include optimization of the detector system to maximize photon detection efficiency.« less

Thermal annealing system and process design to improve quality of large size glasses

Large size optical glass has attracted much attention due to its applications in large optical devices. Fine annealing is widely employed to improve mechanical and optical quality of glass products. During fine annealing, the temperature distribution in glasses is crucial to the final quality of optical glasses as a result of its influence on thermal stress and optical homogeneity. To ensure its high performance, the temperature distribution in glasses should be homogeneous and symmetric, and the maximum temperature difference should be small. In this study, two approaches are proposed to improve the temperature uniformity in glasses during fine annealing. Firstly, the glass blocks are packaged with heat exchange blocks on the top and bottom surfaces, and an insulation layer on the side. Simulation results show that the homogeneity and symmetry of temperature distribution in glasses can be improved. Temperature difference in the horizontal direction can be further reduced in the case using 10mm copper heat exchange block together with 50mm insulation layer. Secondly, a muffle apparatus is utilized. The symmetry of temperature distribution in glasses can be improved. In conclusions, the first approach can be used to achieve more symmetric and homogeneous temperature distribution, while the second approach can be used for changing the symmetry of temperature distribution in glasses. Combining two approaches can be used to design thermal system and industrial fine annealing process of optical glasses upon which the overall stress level can be reduced and the symmetry of the residual stress can be improved.

J0420403 Sパラメータによる積層試料の接着評価法の検討([J042-04]超音波計測・解析法の新展開(4),機械材料・材料加工部門)

Adhesion evaluation method of laminated material using scattering parameter for ultrasonic waves was proposed. Glass blocks were laminated and reflection coefficient (S_<11>) for the ultrasonic waves of swept frequency was measured. As a results, when diameter of the adhesive area was more than 8 mm, ultrasonic waves could be transmitted into the second glass block. Therefore, a possibility of adhesive evaluation of laminated material using our method was demonstrated.

The Optimization of Performance the New Type of Insulation Wall Materials Based on Waste Foam Glasses

A new type of insulation wall is developed based on waste foam glasses. Performance tests small particle size (1~10mm) foam glass block with mass ratio of 30%~50% shows that the coefficient of thermal conductivity and compressive strength of insulation block are blow 0.2w/(m.K) and above 3.10MPa, respectively. This indicates a well insulation performance and mechanical property however the density and strength are not good enough. If the large particle size (20~65mm) are used with the mass ratio of 50~80%, the density can be lower than 400kg/m3 and the coefficient of thermal conductivity and compressive strength of insulation block are 0.2w/(m.K) and 0.5MPa, respectively. This indicates a lighter weight and better insulation performance. If the 44.7% construction waste are added to the insulation walls, the compressive strength can be improved more than 90% and meet the requirement of bearing walls.

THE NA62 EXPERIMENT AT CERN AND THE MEASUREMENT OF THE ULTRA-RARE DECAY K&lt;sup&gt;+&lt;/sup&gt;-&amp;pi;&lt;sup&gt;+&lt;/sup&gt;v&amp;macr;v

The NA62 experiment at CERN aims at the very challenging task of measuring with 10% relative error the Branching Ratio of the ultra-rare decay of the K&lt;sup&gt;+&lt;/sup&gt; into π&lt;sup&gt;+&lt;/sup&gt; ν¯ν which is expected to occur only in about 8 out of 10&lt;sup&gt;11&lt;/sup&gt; Kaon decays. This will be achieved by means of an intense hadron beam, an accurate kinematical reconstruction and a redundant veto system for identifying and suppressing all spurious events. Good resolution on the missing mass in the decay is achieved using a high-resolution beam tracker to measure the kaon momentum and with a spectrometer equipped with straw tubes operating in vacuum. Hermetic veto (up to 50 mrad) of the photon from π&lt;sup&gt;0&lt;/sup&gt; decays is achieved with a combination of large angle veto (with a creative reuse of the old OPAL lead glass blocks), the NA48 liquid Krypton calorimeter and two small angle calorimeters to cover the angle down to zero. The identification of the muons and the consequent veto is performed by a fast hodoscope plane (used in the first level of the trigger to reduce the rate) and by a 17 meter, neon-filled RICH counter which is able to separate pions and muons in the momentum interval between 15 and 35 GeV. Particle identification in the beam (K&lt;sup&gt;+&lt;/sup&gt; separation) is achieved with an H2 differential Cherenkov counter. The trigger for the experiment is based on a multilevel structure with a first level implemented in the readout boards and with the subsequent level done in the software. The aim is to reduce the 10MHz level zero rate to a few kHz sent to the CERN computing centre. Studies are underway to use GPU boards in some key point of the trigger system to improve the performance.&lt;p&gt; &lt;/p&gt;

THE NA62 EXPERIMENT AT CERN AND THE MEASUREMENT OF THE ULTRA-RARE DECAY K&lt;sup&gt;+&lt;/sup&gt;-&amp;pi;&lt;sup&gt;+&lt;/sup&gt;v&amp;macr;v

The NA62 experiment at CERN aims at the very challenging task of measuring with 10% relative error the Branching Ratio of the ultra-rare decay of the K + into π + ν¯ν which is expected to occur only in about 8 out of 10 11 Kaon decays. This will be achieved by means of an intense hadron beam, an accurate kinematical reconstruction and a redundant veto system for identifying and suppressing all spurious events. Good resolution on the missing mass in the decay is achieved using a high-resolution beam tracker to measure the kaon momentum and with a spectrometer equipped with straw tubes operating in vacuum. Hermetic veto (up to 50 mrad) of the photon from π 0 decays is achieved with a combination of large angle veto (with a creative reuse of the old OPAL lead glass blocks), the NA48 liquid Krypton calorimeter and two small angle calorimeters to cover the angle down to zero. The identification of the muons and the consequent veto is performed by a fast hodoscope plane (used in the first level of the trigger to reduce the rate) and by a 17 meter, neon-filled RICH counter which is able to separate pions and muons in the momentum interval between 15 and 35 GeV. Particle identification in the beam (K + separation) is achieved with an H2 differential Cherenkov counter. The trigger for the experiment is based on a multilevel structure with a first level implemented in the readout boards and with the subsequent level done in the software. The aim is to reduce the 10MHz level zero rate to a few kHz sent to the CERN computing centre. Studies are underway to use GPU boards in some key point of the trigger system to improve the performance.

Review: Designing Tomorrow: America’s World’s Fairs of the 1930s and Designing Tomorrow: America’s World’s Fairs of the 1930s

Designing Tomorrow: America’s World’s Fairs of the 1930s National Building Museum, Washington, D.C. 2 October 2010–10 July 2011 Museum of the City of New York, New York 5 December 2012–31 March 2013 A rich selection of images greeted visitors to the Museum of the City of New York from 5 December 2012 to 31 March 2013. Hints of American fairs’ modernist glamor shown in scenic renderings in the entrance hall forecast more pictures in the main display room. On the perimeter walls of a large gallery, black-and-white photographs illustrated American fairs of the 1930s: Chicago’s Century of Progress (1934–34), San Diego’s California Pacific International Exposition (1935–36), Dallas’s Texas Centennial Exposition (1936), Cleveland’s Great Lakes Exposition (1936–37), San Francisco’s Golden Gate International Exposition, and New York City’s World of Tomorrow (both 1939–40). On intermediate partitions, visitors saw renderings of vistas and individual pavilions, objects displayed at the fairs, and advertisements for sponsors’ products. Here and there, they paused to see short news and commercial films, although in the well-filled room, no seats could be provided. Souvenir brochures, booklets, catalogs, and commemorative trinkets appeared near the entrance and in vitrines. Captions to the photographs and short wall-mounted essays offered explanatory information. Crowded captions and pictures made the former sometimes hard to read, dissuading many visitors from learning more about the content of some of the images. The fraternal twin exhibitions in Washington and New York gave a coordinated overview of the fairs, almost as if they were one fair with varied sections. Laura Schiavo and Deborah Sorensen curated the initial and somewhat larger exhibition at the National Building Museum; Jessica Lautin played the same role in New York City. This later version included additional locally pertinent material. A well-illustrated catalogue contained essays on various topics; those not mentioned later in this review are the introduction by Robert W. Rydell; “ ‘Industry Applies’: Corporate Marketing at A Century of Progress,” by Lisa D. Schrenk; a photo-essay by Laura Burd Schiavo titled “Modern Design Goes Public”; Kristina …

Comparison and visualization of focusing wave fields from various time reversal techniques in elastic media.

This Letter presents a series of time reversal experiments conducted on the surface of a fused silica glass block. Four different time reversal techniques are compared using three different imaging conditions. The techniques include two classical time reversal experiments: one with a pulse waveform source and one with an impulse response generated from a chirp signal. The other two techniques utilize the deconvolution, or inverse filter, signal processing methods for obtaining the signals to back propagate using a pulse waveform and an impulse response from a chirp. The max-in-time, symmetry, and energy current imaging conditions are compared.

Environmental persistence of vaccinia virus on materials

Smallpox is caused by the variola virus, and ranks as one of the most serious diseases that could originate from a biological weapon. However, limited data exist on the persistence of variola and related viruses on materials (that may act as fomites), under controlled environmental conditions. To fill these data gaps, we determined the persistence of the vaccinia virus (an established surrogate for the variola virus) as a function of temperature, relative humidity and material. Experiments were conducted with vaccinia virus in a freeze-dried form, using four materials under four sets of environmental conditions. After elapsed times ranging from 1 to 56 days, the virus was extracted from small coupons and quantified via plaque-forming units (PFU). The vaccinia virus was most persistent at low temperature and low relative humidity, with greater than 10(4) PFU recovered from glass, galvanized steel and painted cinder block at 56 days (equivalent to only a c. 2 log reduction). Thus, vaccinia virus may persist from weeks to months, depending on the material and environmental conditions. This study may aid those responsible for infection control to make informed decisions regarding the need for environmental decontamination following the release of an agent such as variola.

Large core, multimode, chalcogenide glass fibre coupler by side-polishing

A novel method for obtaining a multimode optical coupler in chalcogenide glass fibre is described. The fibres used had a large $$\text{ Ge }_{17}\text{ As }_{18}\text{ Se }_{65}$$ core comprising about 74 % of the total cross-sectional area with an optical cladding of $$\text{ Ge }_{17}\text{ As }_{18}\text{ Se }_{62}\text{ S }_{3}$$ . A single arc-shaped U-groove was formed in each of two silicate glass blocks. A length of fibre was embedded into each groove and glued in place. The centre of each fibre length was subsequently side-polished. Finally two such embedded fibres were glued together in close contact to form the coupler, whilst monitoring the coupling ratio at the output.

High-performance brillouin spectroscopy of phonons induced by a piezoelectric thin film with a coaxial microwave resonator

To overcome the low accuracy of acoustic velocity measurements based on Brillouin scattering from thermal phonons, we attempted to utilize induced coherent phonons, which cause intense Brillouin scattering. A ZnO piezoelectric film was used to induce gigahertz-range coherent phonons in a silica glass block sample. An evanescent electromagnetic wave leaked from a coaxial resonator was applied into the film to excite phonons. The scattered light obtained using this simple system was much more intense than that obtained from thermal phonons. This technique will improve the accuracy and reduce the measurement time.

Analytical and Computational Simulation Approaches to Design Low Energy Glass Block

Analytical and Computational Simulation Approaches to Design Low Energy Glass Block. An environmentally friendly process was developed to produce a low embodied energy glass block from waste glasses. The energy efficiency of the glass block is represented by its thermal conductance (U) <3.177 W/m2.K and solar transmittance (SHGC) ≤0.25 as well as visible light transmission (VT) ≥0.27. A cavity was applied to reduce U value while insignificantly reducing VT. Analytical method was used to calculate the U value of glass blocks, ignoring the effect of convection. Ecotect program was used to analyze light level (VT) and heat load (SHGC) of each model. Effect of convection was simulated using a CFD program, which showed air velocity inside the cavity and temperature gradient in glass blocks. Comparing to an application with 3 mm float glass, energy efficiency obtained through applying the glass blocks could reach 96%. This simulation study ignored the presence of adhesive among glass layers that potentially reduces the VT and the SHGC of the glass blocks.

Interlayer and cavity contribution to creating high light-to-solar-gain-ratio glass block from waste glasses

In order to save building energy consumption, glazing in warm humid climates is recommended to have high light-to-solar-gain ratio (LSG). LSG denotes the ratio of the visible light transmittance (VT) to its solar heat gain coefficient (SHGC). In laminated glazing LSG depends on the design of the cavity and (inter) layers. This study explores the contribution of the interlayers and cavity in creating high LSG glass block from laminated waste glasses. Analytical methods and computational simulations using the comparative method and heat balance model were employed to obtain a glass block model with the optimum combination of VT, SHGC and thermal transmittance (U). The cavity effect on the increasing VT is shown by simulation and laboratory test results. Based on SHGC laboratory test results, the presence of an interlayer decreases the simulated SHGC by 69–89%. The LSG for a laminated glass block with a certain number of closed cavities and interlayers can reach 4.35 times the calibrated laboratory LSG.

The large-angle photon veto system for the NA62 experiment at the CERN SPS

The branching ratio (BR) for the decay K+ → π+νν̄ is a sensitive probe for new physics. The NA62 experiment at the CERN SPS will measure this BR to within about 10%. To reject the background from dominant kaon decays with final state photons, the large-angle photon vetoes (LAVs) must detect photons of energy as low as 200 MeV with an inefficiency of less than 10−4. The LAV detectors make use of lead glass blocks recycled from the OPAL electromagnetic calorimeter barrel. We describe the mechanical design and challenges faced during construction, the characterization of the lead glass blocks and solutions adopted for monitoring their performance, and the development of front-end electronics to allow simultaneous time and energy measurements over an extended dynamic range using the time-over-threshold technique. Our results are based on test-beam data and are reproduced by a detailed Monte Carlo simulation that includes the readout chain.