Transparent Glass Window Research Articles

P‐4.8: Unidirectional Observable Aero Signage Display Using Dye‐doped Corner Cube Prisms Which Enable to Make Transparent from Back Side

Suppose that you look Arabic numerals on transparent glass windows or in the air. Which does it mean ‘85’ or ‘28’? You end up watching the mirrored images when you view from back side. So let us make the mirrored image invisible. To solve mirrored image problems of an aero signage which means images are floating in the air, our research group has utilized dye‐doped prisms and total internal reflection in optics. You know that water is generally colorless and transparent but the water in a bath tub is little blue. The color changes depending on the depth of water. The deeper, the darker water becomes blue. This is the reason why some color is generated in the dye‐doped material. In 2021, we presented a unidirectional observable display using letterings made by intaglio printings for arranging dye‐doped tiny prisms on a glass window. You can watch these colored letterforms from front and transparent pixels from back. But this 2021 model has a little defect that colors are less vivid because of color generating mechanism by twice reflection in conventional optical prisms using transparent materials for making transparent from back side. In this paper, the authors show an aero signage display using dye‐doped corner cube prisms which can lengthen light paths in the prism by multi‐times reflections to avoid the semi‐transparent problem which means colors are not vivid.

P‐3.22: One‐way Observable Aero Signage Display Using Optical Prisms Doped with Dye and Pigments Which Enable to Make Transparent from Back Side

Suppose that you look Arabic numerals on transparent glass windows or in the air. Which does it mean ‘85’ or ‘28’? You end up watching the mirrored images when you view from back side. So let us make the mirrored image invisible. This paper shows a one-way observable display for aero signage whose images are floating in the air. To solve mirrored image problems of an aero signage, our research group has utilized dye-doped prisms and total internal reflection in optics. You know that water is generally colorless and transparent but the water in a bath tub is little blue. The color changes depending on the depth of water. The deeper, the darker water becomes blue. This is the reason why some color is generated in the dye-doped material. In 2021, we presented a one-way observable display using letterings made by intaglio printings for arranging dye-doped tiny prisms on a glass window. You can watch these colored letterforms from front and transparent pixels from back. But this 2021 model has a little defect that colors are less vivid because of color generating mechanism using transparent materials for one-way observing. In this paper, the authors show special designed optical prisms which are doped with dye and pigments to avoid the semitransparent problem that means colors are not vivid.

P‐6.8: One‐way Observable Window Signage Display Using Dye‐doped Thin Resin Layers Which Enable to Make Images Invisible from Back Side

Window signage or signs are cost‐effective ways to attract attention from streets. Assume that you draw something on a transparent glass window. It is difficult to understand your drawing correctly since one observes the mirrored text and graphics from opposite side. The authors dislike this mirrored imaging problem, although it is not a fatal defect. This paper shows a one‐way observable imaging display on the glass window using dye‐doped thin resin layers for unidirectional color generating by light controls and material development. The authors developed one‐way observable window signage display systems which are composed of dye‐doped thin resin films cut for letterings and graphics or dye‐doped resin inks for hand‐drawings.

P‐8.12: One‐way Observable Floating Image Display for Aero Signage Using Micro Optical Prisms Which Enable to Make Transparent View from Back Side

Suppose that you look Arabic numerals on transparent glass windows or in the air. Which does it mean ‘85’ or ‘28’? You end up watching the mirrored images when you view from back side. This paper shows a one‐way observable display for aero signage whose images are floating in the air. To solve mirrored image problems of an aero signage, the authors have utilized dye‐doped prisms and total internal reflection in optics. You know that water is generally clear and transparent but the water in a bath tub is little blue. The color changes depending on the depth of water. The deeper, the darker water becomes blue. This is the reason why some color is generated in the dye‐doped material. The authors put the letterings made by intaglio printings for arranging dye‐doped tiny prisms on a glass window. You can watch these colored letterforms from front and transparent pixels from back. Moreover the authors discuss a one‐way observable edgeilluminated window signage display which enables us to observe light emitting signs in the dark night without requiring external illuminating lights.

P‐15.1: Projection Display Screen for Floating Signage Which Enables to Make Images Invisible from Back Side Using Light Control Technology

Window decals are stickers that help catch the eyes of customers and look like floating images in the air because of the transparent glass window. But these graphic signs have defects. They are problems of mirrored imaging and still images. The authors are just wondering the following; Can't we change and animate the graphic image on the window? It is common knowledge that the drawing on the glass is always same. So let us make the window decals change and animate. This paper shows the one‐way observable projection display screen using light control technologies in order to avoid these defects. The authors proposed the unidirectional or one‐way observable window signage display in 2019. Our polarized light control mechanism for projection display is simpler than the case of the 2019 signage model. You can confirm that the light control technique realizes one‐way observable projection.

P‐6.3: Origami‐inspired Connectable Modular‐pixel Imaging Display Systems Which Enable Colors to Change for Aero Signage with Diagonal Connects

Our research group has been developing an aero signage display. The word ‘aero’ means that its image is floating in the air. The authors have noticed that the important technology in aero signage is ‘transparent.’ Suppose you find out window decals which are put on the glass window of shops. You end up watching the mirrored images if you watch the decals on transparent glass window from inside of the shop. In aero signage, the technique which enables to display unidirectional (or one‐way) observable image(viewing angle control) is very important. Our proposed self‐assembly joint mechanism is one of the essential technology for aero signage which enables to make transparent view from back side.

Full Optical Contactless Thermometry Based on LED Photoluminescence

In this work, we report a contactless temperature measurement method based on the photoluminescence (PL) of an AlInGaP light-emitting diode (LED) structure under open-circuit conditions. The proposed method has been evaluated between 90 and 460 K, but a broader temperature range is possible. The system is based on the temperature-dependent PL variation of a commercial AlInGaP LED designed to emit at 630 nm at room $T$ . The sample is placed inside a temperature-controlled cryostat equipped with a transparent glass window. After exciting the sample by means of a green 532-nm laser, the emitted PL spectrum has been collected by an optical fiber and acquired by means of a charge-coupled device (CCD) array spectrometer. In the first part of the work, the most effective calibration is discussed as a function of the properties of the sampled spectrum; both PL emission peak and spectral width have been considered to calculate the optimal estimated temperature. The effect of spectrometer resolution on temperature estimation has been evaluated by comparing and analyzing the results from two spectrometers with different pixel densities. The effects of excitation intensity and angular positioning have also been evaluated. Finally, uncertainty due to calibration, together with measurement accuracy and precision, has been calculated over 50 acquisitions resulting on average in ±1, ±0.7, and ±0.3 K, respectively, on a temperature range of 300 K.

Benchmark Dataset Based on Category Maps with Indoor–Outdoor Mixed Features for Positional Scene Recognition by a Mobile Robot

This study was conducted to develop original benchmark datasets that simultaneously include indoor–outdoor visual features. Indoor visual information related to images includes outdoor features to a degree that varies extremely by time, weather, and season. We obtained time-series scene images using a wide field of view (FOV) camera mounted on a mobile robot moving along a 392-m route in an indoor environment surrounded by transparent glass walls and windows for two directions in three seasons. For this study, we propose a unified method for extracting, characterizing, and recognizing visual landmarks that are robust to human occlusion in a real environment in which robots coexist with people. Using our method, we conducted an evaluation experiment to recognize scenes divided up to 64 zones with fixed intervals. The experimentally obtained results using the datasets revealed the performance and characteristics of meta-parameter optimization, mapping characteristics to category maps, and recognition accuracy. Moreover, we visualized similarities between scene images using category maps. We also identified cluster boundaries obtained from mapping weights.

Olfactory Atlases with an Array of Porphyrinoids Coated ZnO Nanoparticle

Olfactory Atlases with an Array of Porphyrinoids Coated ZnO Nanoparticle

A Simple Approach to Design and Fabricate an Efficient Heat Pump

A low cost and indigenous experimental training, testing and process optimization setup of the heat pumping system is designed, developed and fabricated for the engineering students. The setup can be an effort to provide an indigenous option and import substitution for the local industries and academic institutions. The system uses difluoro-monochloromethane (CHCIF2) for the heat transport mechanism which has a heat of vaporization (ΔHvap) of 233.95 kJ/kg at the boiling point of -40oC. The control compression and expansion of the gas is performed by using the electro-mechanical controls and semi-hermetic compressor. The whole experimental setup is installed on the bench top table with vertical installation in open-air inside the laboratory. The change in pressure and temperature values at various stages of the setup is monitored by sensors, gauges, and visual displays. Physical states of the transport medium, i.e. liquid, vapors and super vapors are monitored by installing the transparent glass windows in the passage of transport medium. Hands-on experiments and procedures can be run on this setup in order to acquire deeper knowledge about design and process optimization of thermodynamical parameters, such as coefficient of performance (COP), Carnot cycle, dynamics of pressure-temperature imbalance during operating cycles and phase transformation of the transport medium under several operating conditions and parameters.

A Simple Approach to Design and Fabricate an Efficient Heat Pump

A low cost and indigenous experimental training, testing and process optimization setup of the heat pumping system is designed, developed and fabricated for the engineering students. The setup can be an effort to provide an indigenous option and import substitution for the local industries and academic institutions. The system uses difluoro-monochloromethane (CHCIF2) for the heat transport mechanism which has a heat of vaporization (ΔHvap) of 233.95 kJ/kg at the boiling point of -40oC. The control compression and expansion of the gas is performed by using the electro-mechanical controls and semi-hermetic compressor. The whole experimental setup is installed on the bench top table with vertical installation in open-air inside the laboratory. The change in pressure and temperature values at various stages of the setup is monitored by sensors, gauges, and visual displays. Physical states of the transport medium, i.e. liquid, vapors and super vapors are monitored by installing the transparent glass windows in the passage of transport medium. Hands-on experiments and procedures can be run on this setup in order to acquire deeper knowledge about design and process optimization of thermodynamical parameters, such as coefficient of performance (COP), Carnot cycle, dynamics of pressure-temperature imbalance during operating cycles and phase transformation of the transport medium under several operating conditions and parameters.

Influence of draft tube water injection system on cavitation behaviour in a full-scale Francis turbine with visual access

This paper describes the results of a comprehensive and ongoing project to control unsteady fluid-dynamic behaviour and associated effects at Svorka hydro power plant (25 MW, 260 m, 600 rpm), operated by Statkraft in Norway. This Francis unit had an original air admission system installed on the draft tube wall and turbine shaft. However, these systems did not perform satisfactorily to prevent high intensity pressure fluctuations due to vortex rope at part load. To mitigate them, a complementary draft tube water injection system, designed by Flow Design Bureau AS (FDB), was installed in 2010. Moreover, the runner suffered from cavitation pitting on the blades and a measuring campaign with several accelerometers and an acoustic emission sensor concluded that the unit was susceptible to high load cavitation erosion. Given the complexity of the turbine flow, it was decided to install four transparent acrylic glass windows on the draft tube, allowing for visual access to the runner blades and outlet flow. To evaluate the influence of the draft tube injection system on the cavitation behaviour, a series of measurements of cavitation intensity were carried out. High frequency data from the sensors were processed with demodulation techniques at various expected modulation frequencies, particularly the blade passing frequency and the frequency of the draft tube vortex rope. Furthermore, the pressure pulsations were measured and quantified with pressure sensors on the draft tube wall. The results indicate that draft tube water injection has little or no effect on the measured cavitation intensity in the runner. However, other aspects of the machine, including the seasonal and daily variation of the submergence level, must be taken into consideration. In conclusion, it appears that additional long-term observations are needed to clarify the global dynamic behaviour along the entire operating range.

Comparative Study between Solar Dryer and Open Sun dried Tomato under North Plateau Climatic Zone

The solar dryer consists of transparent glass window, tray, solar photovoltaic fans and solar panel. The solar radiation passes through the transparent glass window, located on the top of the cabinet. The cabinet is made of anti-corrosive material and of modular nature to meet the varying sizes and loading capacities of food products, ranging from 7 to 8 kg. The ambient air enters from the bottom of the cabinet and gets heated up with solar radiation incident from the top window. The heat energy is trapped in the cabinet and heats up the air. The hot air passed through the trays, carries the moisture from the product to the space below the glass. Then it is exhausted by Solar Photovoltaic Fans. The forced circulation of air in the cabinet is achieved through this solar fan. Assessment of the dryer showed a raised temperature of about 470c attainable in the drying chamber. The dryer temperature and drying rate was found to be higher than the natural open sun drying method. The dryer was able to reduce moisture content of tomato from initial moisture content of 93 per cent wet basis to 4 per cent in three days with effective drying time of 24hr and drying rate of 0.03833 kg/hr, whereas the traditional sun drying was able to reduce moisture content of tomato from initial moisture content of 93 per cent wet basis to 4 per cent in five days with drying time of 34hr and drying rate of 0.0272 kg/hr. The results showed a considerable advantage of solar dryer over the traditional open sun drying method in term of drying rate and less risk for spoilage.

Facile fabrication of microfluidic surface-enhanced Raman scattering devices via lift-uplithography.

We describe a facile and low-cost approach for a flexibly integrated surface-enhanced Raman scattering (SERS) substrate in microfluidic chips. Briefly, a SERS substrate was fabricated by the electrostatic assembling of gold nanoparticles, and shaped into designed patterns by subsequent lift-up soft lithography. The SERS micro-pattern could be further integrated within microfluidic channels conveniently. The resulting microfluidic SERS chip allowed ultrasensitive in situ SERS monitoring from the transparent glass window. With its advantages in simplicity, functionality and cost-effectiveness, this method could be readily expanded into optical microfluidic fabrication for biochemical applications.

Controlling sound radiation through an opening with secondary loudspeakers along its boundaries

We propose a virtual sound barrier system that blocks sound transmission through openings without affecting access, light and air circulation. The proposed system applies active control technique to cancel sound transmission with a double layered loudspeaker array at the edge of the opening. Unlike traditional transparent glass windows, recently invented double-glazed ventilation windows and planar active sound barriers or any other metamaterials designed to reduce sound transmission, secondary loudspeakers are put only along the boundaries of the opening, which provides the possibility to make it invisible. Simulation and experimental results demonstrate its feasibility for broadband sound control, especially for low frequency sound which is usually hard to attenuate with existing methods.

Thermal Runaway Characterization of Li-Ion Batteries Under External Heating Conditions

Recent Li-ion battery fire incidents in smartphones, hoverboards, e-cigarettes, electric vehicles, and aircrafts highlight the limited understanding of battery thermal runaway failure and inadequacy of current battery safety or protection mechanisms. Li-ion battery thermal runaway can occur due to the presence of material defects, operation under abusive/extreme conditions, or cumulative damage under normal operation. Electrical and thermal characterization of Li-ion batteries under thermal runaway conditions is necessary to improve the battery safety. In the past various studies have been conducted to investigate thermal runaway failures under different operating conditions [1-3]. This work studies the effects of additional parameters and operating conditions on Li-ion battery thermal runaway induced by external heating of the battery. External heating is a common loading condition for batteries located in close proximity to an electronic circuit or inside a battery pack. A detailed electrical and thermal characterization of battery has been performed to understand the failure mechanisms and to provide guidance on battery monitoring and safety management. Experiments were conducted on commercial 18650 Li-ion cells with 2600 mAh nominal capacity (at C/5) and nominal voltage of 3.6V. These cells have safety vents located below the positive terminal to allow release of gases. Cells in fully charged and fully discharged conditions were used for the experiments. A high temperature Nickel Chromium heating wire was wrapped around the cells and powered by a DC source to raise the cell temperature. The heating rate (current) of the wire was varied to study its effects on thermal runaway. Three different external heating cut-off conditions were investigated in this study: heating cut-off after the occurrence of thermal runaway, heating cut-off just after the trigger of cell venting, and heating cut-off at temperatures below cell venting trigger temperature. Two K-type thermocouples were mounted on cell near the two ends (terminals) to monitor the cell surface temperature. Cell voltage measurements were also recorded during the entire testing. All the experiments were conducted inside an in-house explosion chamber with a transparent glass window for the video recording. The experimental results identify the operating conditions with high susceptibility to thermal runaway failure. The electrical and thermal observations indicate the possible cell failure mechanisms, reveal different stages of cell failure, and correlate the electrical and thermal failure behavior of the cell. The results show that the heating of fully charged cell up to a critical temperature level can lead to electrical failure (voltage drop below the cell cut-off voltage) even if the cell does not undergo thermal runaway. Parameters such as cell venting trigger temperature, cell maximum temperature, cell self-heating rate, voltage drop, and time duration of the thermal runaway have been estimated from the measurements. The learnings from this study form the basis of recommendations for improvement in battery safety management. References H. Maleki, G. Deng, A. Anani, J. Howard, Thermal stability studies of Li-ion cells and components, J. Electrochem. Soc. 146 (9) (1999) 3224-3229.X. Liu, S.I. Stoliarov, M. Denlinger, A. Masias, K. Snyder, Comprehensive calorimetry of the thermally-induced failure of a lithium ion battery, J. Power Sources 280 (2015) 516-525.A.W. Golubkov, S. Scheikl, R. Planteu, G. Voitic, H. Wiltsche, C. Stangl, G. Fauler, A. Thaler, V. Hacker, Thermal runaway of commercial 18650 Li-ion batteries with LFP and NCA cathodes – impact of state of charge and overcharge, RSC Adv. 5 (2015) 57171-57186.

In-line rheo-polarimetry: A method to measure in real time the flow birefringence during polymer extrusion

This work presents a new optical detection system, an in-line rheo-polarimeter, to measure in real time polymer flow birefringence during extrusion. The total transmitted cross polarized light intensity is measured, converted into optical path difference, which is corrected for the transparent glass windows stress birefringence and then converted into the polymer flow birefringence in real time. To validate the in-line measurements, a bench assessment was done using cast sheets of polycarbonate with known optical path difference as standards. The flow birefringence of polystyrene was measured in-line during the extrusion process, attaining values up to −4×10−4, close to those found in the literature. The flow birefringence of various polystyrene samples was measured in-line during the extrusion showing the effect of increasing molecular weight on the polymer chain orientation.

Transparent Glass Window with Energy-Saving and Heat Insulation Capabilities

This paper proposes capabilities of transparent glass window design with energy-saving and heat insulation for carbon reduction issues. An optical thin film coating technology is used for coating multilayered dielectric materials on the transparent glass to achieve an infrared ray shielding effect; especially to prevent rising temperature easily of indoor room. That is infrared ray incidence from outdoor and the thermal flux effect of the transparent window influent the indoor room temperature. In winter, the outdoor temperature is increased more easily by infrared ray incidence. However, the heat insulation window allows 98% of visible light penetration through the window and also allows 90% of infrared light reflection and roughly 10% of infrared light penetration into indoor.

Laser pulse heating of nuclear fuels for simulation of reactor power transients

It is important to study the behaviour of nuclear fuels under transient heating conditions from the point of view of nuclear safety. To simulate the transient heating conditions occurring in the known reactor accidents like loss of coolant accident (LOCA) and reactivity initiated accident (RIA), a laser pulse heating system is under development at BARC, Mumbai. As a prelude to work on irradiated nuclear fuel specimens, pilot studies on unirradiated UO2 fuel specimens were carried out. A laser pulse was used to heat specimens of UO2 held inside a chamber with an optically transparent glass window. Later, these specimens were analysed by metallography and X-ray diffraction. This paper describes the results of these studies.

Integration of transparent glass window with LTCC technology for μTAS application

The LTCC substrate makes it possible to build various microsystems which integrate not only passive components such as resistors, capacitors and inductors but also 3D structures such as cavities and channels. Nevertheless non-transparency is a main limitation of the LTCC-based microfluidic systems. The goal of this paper is to present technology which allows an optical transparent element to integrate with LTCC co-firing process. A micrototal analysis system (μTAS), which is based on the LTCC–glass technology, enables optical measurements. The study shows that integration of sodium glass material is feasible not only with zero-shrinkage LTCC (HL 2000, HL 800) but also with a standard one (DP 951). A FEA (finite element analysis) is used to calculate stress inside the LTCC–glass structure. A series of LTCC–glass windows with different sizes and shapes is investigated to observe size limitation of the integration method. The example ceramic–glass structures (chambers, mixer) with glass windows are made in order to present the possibilities of this new technology.