Transparent Wall Research Articles

A laser absorption spectroscopy chamber system based on closed dynamic chamber method for multi-point synchronous monitoring ammonia emissions

This study reports on the field testing of a newly and originally designed laser absorption spectroscopy chamber (LASC) system based on closed dynamic chamber method, which is well suited for multi-point synchronous measurement of ammonia emissions in field multiple plot experiment. Main design feature of the LASC system is individual multi-reflection cells for each chamber, achieving the synchronous in-situ monitoring ammonia emissions of all the chambers. Two movable covers for automated opening and closing of the chamber, and the highly transparent chamber walls made of acrylic plate minimize the disturbance of the chamber deployment on the ammonia transport process in the chamber. Controlled field assessment experiment was conducted to evaluate the applicability and reliability of the LASC system. The results indicated that the optimum time length of chamber closure for monitoring ammonia emission is 3 min, and the appropriate time length of chamber ventilation is 17 to 37 min. The LASC system has higher accuracy for measuring ammonia emission rate and reliability for comparatively measuring ammonia emissions from different treatments than the traditional chamber methods.

High-speed low-coherence interferometry of fuel films in impinging gasoline direct injection sprays

Quantitative experimental characterization of dynamic fuel film deposition processes is critical to developing better understanding and modeling of cold-start behavior in gasoline direct injection engines. Low-Coherence Interferometry (LCI) offers a quantitative fuel film thickness diagnostic that is immune or resistant to major confounding influences that limit other optical diagnostics in engine-relevant environments. This work describes an extension of spectral LCI techniques to high-speeds (10 kHz) that are capable of resolving the dynamics of fuel film deposition and evaporation in impinging gasoline sprays. Two approaches to LCI, Michelson interferometry and Fizeau interferometry, were tested and results demonstrate the superiority of the Fizeau configuration for enclosed vessel experiments. Experiments were performed at cold start conditions in an enclosed spray chamber with a gasoline spray impinging on a transparent wall. High-speed LCI was used to measure fuel film thicknesses and dynamic changes in thickness. The measurements were used to observe variation in film thickness and behavior with changes in system temperature and fuel composition.

A ring shear device to simulate cryosphere processes

We have developed a new cryogenic ring shear device at the University of Wisconsin–Madison to simulate cryosphere processes, with an emphasis on the physics of glacier slip. The device spins a ring of ice (inner diameter of 20 cm, outer diameter of 60 cm, height of ∼20–30 cm) at the pressure melting point over a rotationally fixed bed. The ice ring is spun at a prescribed velocity (range of ∼0.01–1000 m a−1) while the resistance to slip is measured. A ram at the base of the device applies a vertical load to the sample chamber to simulate the overburden pressure (range ∼5–915 kPa) felt at a glacier’s base. The sample chamber is constructed with transparent acrylic walls, allowing subglacial processes to be observed directly by a series of cameras. The entire device is housed in a large walk-in freezer. In the freezer, the sample chamber is submerged in a tub of temperature-controlled fluid that precisely regulates heat flux into the sample chamber, replicating in situ conditions and allowing for prolonged experiments that last weeks to months. This device can be used to study several of the most unconstrained physical processes that regulate glacier movement and, in doing so, greatly improve predictions of glacier contributions to sea-level rise.

Stilt houses in Southeastern and Northern European climate conditions

The comparison of the annual specific primary energy consumption (SPEC) of the different stilt house models and corresponding slab-on house (SOH), the stilt house with fully opened (SWAC) and fully closed zone below the raised ground floor (lower zone) was investigated. The stilt house with fully closed zone implies the stilt house with transparent (SWTC), non-transparent (SWNTC) and variable transparent (SHSC) walls of the lower zone. The comparison was conducted for different climate conditions, insulation levels and ground temperature scenarios. The most favourable type of stilt house is the house with transparent walls of the lower zone during winter and non-transparent walls during summer (SHSC). The average percentage increase in SPEC of stilt houses, in relation to the SPEC of the corresponding SOH ranges from a maximum of 12.17% (SWAC) to a minimum of 3.63% (SHSC), for the Southeastern Europe, and from 12.54% (SWAC) to 4.62% (SHSC), for the Northern Europe climatic conditions, respectively.

Blue tits are outperformed by great tits in a test of motor inhibition, and experience does not improve their performance.

Motor inhibition refers to the ability to inhibit immediate responses in favour of adaptive actions that are mediated by executive functions. This ability may be an indication of general cognitive ability in animals and is important for advanced cognitive functions. In this study, our aim was to compare motor inhibition ability of two closely related passerines that share the same habitat. To do this, we tested motor inhibition ability using a transparent cylinder task in blue tits in the same way as we previously tested great tits. To test whether the experience of transparent objects would affect the performance of these species differently, both in the present experiment using blue tits and our previous one on great tits, we divided 33 wild-caught individuals into three different treatment groups with 11 birds each. Before the test we allowed one group to experience a transparent cylindrical object, one group to experience a transparent wall and a third group was kept naive. In general, blue tits performed worse than great tits, and unlike the great tits, they did not improve their performance after experience with a transparent cylinder-like object. The performance difference may stem from difference in foraging behaviour between these species.

An experimental baseline for ice-till strain indicators

Subglacial till can deform when overriding ice exerts shear traction at the ice–till interface. This deformation leaves a strain signature in the till, aligning grains in the direction of ice flow and producing a range of diagnostic microstructures. Constraining the conditions that produce these kinematic indicators is key to interpreting the myriad of features found in basal till deposits. Here, we used a cryogenic ring shear device with transparent sample chamber walls to slip a ring of temperate ice over a till bed from which we examined the strain signature in the till. We used cameras mounted to the side of the ring shear and bead strings inserted in the till to estimate the strain distribution within the till layer. Following the completion of the experiment, we extracted and analyzed anisotropy of magnetic susceptibility (AMS) samples and created thin sections of the till bed for microstructure analysis. We then compared the AMS and microstructures with the observed strain history to examine the relationship between kinematic indicators and strain in a setting where shear traction is supplied by ice. We found that AMS fabrics show a high degree of clustering in regions of high strain near the ice–till interface. In the uppermost zone of till, k1 eigenvector azimuths are generally aligned with ice flow, and S1 eigenvalues are high. However, S1 eigenvalues and the alignment of the k1 eigenvector with ice flow decrease nonlinearly with distance from the ice–till interface. There is a high occurrence of microshears in the zone of increased deformation.

Эксперименты по ультразвуковому разделению модельной водно-масляной эмульсии

The dynamics of model water-in-oil emulsions based on PMS-5 and PMS-100 silicone oils in the field of a standing ultrasonic wave is studied experimentally. In the experiments, a resonator cell with transparent walls is used. The ultrasonic transducer is installed in the cell’s vertical wall; its radiation axis is directed horizontally, across the working layer. Experiments are performed at an ultrasonic exposure frequency of ~ 80 kHz and a dispersed phase concentration of 5%. Photo-video recording of the images of the liquid layer in transmitted light is carried out, with their sub-sequent digital processing. The brightness levels of the patterns of the working fluid layer in the transmitted scattered light are measured. An ultrasonic wave leads to a redistribution of the liquids, which can be distinguished by a change in the brightness patterns of the light passing through the working layer. This is evidence of ultrasonic separation due to acoustophoresis. Two main effects caused by ultrasonic action and preventing the separation of the emulsions are experimentally demonstrated. Ultrasonic oscillations cause cavitation in the liquid volume and also acoustic streaming (primarily the ‘quartz wind’), which become noticeable at a relatively high intensity of ultrasonic exposure. Experiments show that the integral brightness of images varies nonmonotonically with change in the intensity of ultrasonic exposure. The nature of this dependence correlates with the manifestation of acoustic streaming and is consistent with the results of other authors.

Features of material movement in a vertical chamber of a vibratory jaw crusher when producing a fine-grained product

Currently, vibrating jaw crushers show a fairly high efficiency of the technological process. An extensive amount of research carried out at the Dnipro University of Technology made it possible for the first time to substantiate the possibility of using a vibratory jaw crusher with a vertically located chamber and a pendulum suspension of the jaws as an independent grinding unit for the production of powder materials. The high-frequency impact nature of the load on the material implemented in vibrating jaw crushers made it possible to reduce the energy consumption and metal consumption of the plant, to increase the degree of crushing, which can reach the value i > 100. However, the specifics of the process of interaction of the material with the surface of the jaws in the vertical working chamber and the features of its unloading remain unknown. The refinement of this process was carried out by an experimental method on a laboratory sample of a vibratory jaw crusher ВЩД-130 using high-speed photography. The crusher includes the main elements: a body mounted on elastic elements, crushing jaws, articulated with the body by means of axes. The side surfaces of the crushing chamber are limited by transparent glass walls rigidly connected to the crusher body. The vertical movement of the jaws was determined by the readings of the vernier. The starting material was pieces larger than 40 mm and large bulk material with a grain size of 10…15 mm. An analysis of the nature of the movement of material throughout the crushing chamber showed the need to consider the chamber of a vibratory jaw crusher as two interconnected zones: crushing and grinding. Further studies were carried out for each zone.The productivity of the crushing zone is determined by a known method. It is necessary to create a rational profile of the working surface of the jaws on the basis of additional studies. Studies of the grinding zone made it possible to obtain a physical picture of the interaction of the material with the jaws over the period. In the lowest position, at the initial moment of unloading, the speed of the finished product is practically zero. When determining the productivity of the grinding zone, it is advisable not to take into account the unloading of the material at the initial speed.

Cell monitoring with optical coherence tomography

Background aimsWe evaluated a commercially available instrument, OCTiCell (chromologic.com/octicell), for monitoring cell growth in suspended agitated bioreactors based on optical coherence tomography. OCTiCell is an in-line, completely non-invasive instrument that can operate on any suspended-cell bioreactor with a window or transparent wall. In traditional optical coherence tomography, the imaging beam is rastered over the sample to form a three-dimensional image. OCTiCell, instead uses a fixed imaging beam and takes advantage of the motion of the media to move the cells across the interrogating optical beam. ResultsWe found strong correlations between the non-invasive, non-contact, reagent-free OCTiCell measurements of cell concentration and viability and those obtained from the automated cell counter, and the XTT viability assay, which is a colorimetric assay for quantifying metabolic activity. ConclusionsThis novel cell monitoring method can adapt to different bioreactor form factors and could reduce the labor cost and contamination risks associated with cell growth monitoring.

Comprehensive Computational Model for Coupled Fluid Flow, Mass Transfer, and Light Supply in Tubular Photobioreactors Equipped with Glass Sponges

The design and optimization of photobioreactor(s) (PBR) benefit from the development of robust and quantitatively accurate computational fluid dynamics (CFD) models, which incorporate the complex interplay of fundamental phenomena. In the present work, we propose a comprehensive computational model for tubular photobioreactors equipped with glass sponges. The simulation model requires a minimum of at least three submodels for hydrodynamics, light supply, and biomass kinetics, respectively. First, by modeling the hydrodynamics, the light–dark cycles can be detected and the mixing characteristics of the flow (besides the mass transport) can be analyzed. Second, the radiative transport model is deployed to predict the local light intensities according to the wavelength of the light and scattering characteristics of the culture. The third submodel implements the biomass growth kinetic by coupling the local light intensities to hydrodynamic information of the CO2 concentration, which allows to predict the algal growth. In combination, the novel mesoscopic simulation model is applied to a tubular PBR with transparent walls and an internal sponge structure. We showcase the coupled simulation results and validate specific submodel outcomes by comparing the experiments. The overall flow velocity, light distribution, and light intensities for individual algae trajectories are extracted and discussed. Conclusively, such insights into complex hydrodynamics and homogeneous illumination are very promising for CFD-based optimization of PBR.

Optical and experimental evaluation of a directly irradiated solar reactor for the catalytic dry reforming of methane

Dry reforming of methane is a process to produce syngas which is a major precursor for many chemicals and ultra-clean fuels. It is a CO2-assisted process that leads to the conversion of CO2 to higher-value products but is also a highly endothermic process that requires significant amounts of energy in the form of CO2 emitting fuels. For these reasons, this study focused on the direct utilization of concentrated solar energy by irradiating the catalyst directly rather than via a heat transfer fluid or conductive heat transfer. In addition, it uniquely adopts a tubular reactor with transparent (quartz) walls configuration, which allows extending the length of the irradiated (hot) zone to control the residence time. The new reactor was designed using Monte-Carlo ray-tracing modeling and evaluated experimentally using a commercial Ni-based catalyst. In brief, the reacting gas mixture (CH4:CO2 − 5 %: 5 %) was fed into the reactor at weight gas hourly space velocities of around 17–58 l h−1g−1 and three different temperature levels (550 °C, 650 °C, and 800 °C). Although the non-conventional mode of heating, the achieved methane conversions (∼93 % at 800 °C to ∼ 53 % at 550 °C) and H2 / CO ratios (∼0.9 at 800 °C to ∼ 0.4 at 550 °C) were similar to literature studies with the same catalyst. At the same time, the quartz walls showed no degradation after more than 80 h of intermittent testing. On the other hand, the overall energy efficiency was estimated to be less than 1 %, considering the radiation intercepted by the reactor system. However, it rose to 5 % − 25 % when correcting for the actual amount of irradiance on the catalytic bed.

Preliminary evidence of tool use in an Australian magpie?

Abstract We investigated tool use in twelve wild-caught Australian magpies. When presented with a tool use apparatus consisting of two transparent walls with a food reward placed in-between, seven magpies pulled the stick out of the apparatus acquiring the food within. On one occasion, one magpie manipulated the removed stick, carried it back to the apparatus, dropped it between the two walls and proceeded to rake out the food within reach of its beak. We believe this observation is important for the field of comparative cognition as it (1) is the first study to report stick tool use in Australian magpies, and (2) shows a novel behaviour in a ground foraging bird that, as far as we know, do not naturally use tools for food extraction. This study provides preliminary evidence that Australian magpies may be added to the list of bird species that can use tools.

Overall Visibility Might Offer False Affordance to Indoor Wayfinding: The Role of Global and Local Landmarks

Using a virtual 3D model of a shopping center, this study explored whether greater visibility provided by transparent walls in the building model, along with the presence of global and local landmarks, facilitated indoors wayfinding. Participants observed video clips of a virtual walkthrough either in a building with transparent or opaque walls, responded to wayfinding questions, and their eye movements were tracked while watching the video. Findings showed no significant difference between participants in the transparent and opaque building in answering wayfinding questions. Eye movements showed significantly longer eye fixations for participants in the transparent building compared to participants in the opaque building, in addition to longer fixations on global landmarks compared to local landmarks. Taken together, the findings imply that the greater visibility through the transparent walls may have offered false wayfinding affordance, rather than facilitate wayfinding decisions.

Enhancement the productivity of drum solar still utilizing parabolic solar concentrator, phase change material and nanoparticles' coating

This study aims to improve fresh water productivity from seawater or brackish water utilizing renewable energies by a solar desalination system, so an experimental study conducted to improve the performance of the drum solar still (DSS) utilizing transparent walls of SS, parabolic solar concentrator (PSC), phase change material (PCM), nanoparticles' coating (NC) and external condenser. PSC will be utilized to concentrate sun rays on the drum's back side, which raised the rate of evaporation, but the high temperature of the glass due to the presence of the PSC has a negative impact on the solar still's condensation rate. Two different methods used to solve the problem of high temperature of the glass to increase the productivity of the DSS, the first, using a fan to draw the generated vapor and condense it in an external condenser and the second is use of PCM-Ag mixture to absorb the excess energy in times of intense radiation and recover it after that at the time of low radiation. The results indicated that, the boiling point of saline water inside the DSS was reached using the new design of the DSS basin, which led to a significant increase in the amount of evaporation. Additionally, the maximum improves in DSS productivity when utilized NC, PSC and external condenser was achieved at 0.3 rpm, where the production enhancement was around 320 % with efficiency of 72 %.

Economic benefits of preventing bird collisions in South Korea: findings from a choice experiment survey.

Bird deaths due to collisions with artificial structures, such as glass windows of buildings and transparent noise barriers, are continuing to occur in South Korea. The government is trying to prevent bird collisions by increasing the attachment of specially designed tapes to help birds avoid windows. This article estimates the economic benefits arising from the prevention of collisions by applying a choice experiment (CE). For this purpose, a CE survey of 1000 South Korean interviewees was conducted. The four attributes to be attached with the tapes for the CE application were a transparent soundproof wall window on an expressway, a transparent soundproof wall window on a general road, a glass window in a public building, and a glass window in a private building. The unit was the percentage of each structure with the tapes attached to the window. The marginal values of a one-unit (1%p) increase in each attribute were computed to be KRW 534 (USD 0.46), KRW 233 (USD 0.20), KRW 1,318 (USD 1.13), and KRW 12,930 (USD 11.05), respectively. This quantitative information will be an important reference for implementing the prevention policy. For example, based on the collision prevention of 1000 birds per structure, the priority for attaching tapes can be placed in the order of expressways, public buildings, private buildings, and general roads.

Three-dimensional laser scanning for large-scale as-built surveying of 2022 Beijing Winter Olympic Speed Skating Stadium: A case study

The latest 3D laser scanning technology is implemented in a practical project—2022 Beijing Winter Olympic Speed Skating Stadium—to investigate its effectiveness on the large-scale as-built surveying of civil infrastructures. The laser scanning was used for measuring the vertical deformation of flexible orthotropic cable net roof structure and for assessing the installation tolerance of curved glass curtain wall system. It was observed that 66% of clamps in the flexible roof structure showed vertical deviations within the range of ±5 mm and 94% of clamps showed deviations within ±10 mm. Additionally, about 60% of the vertical joints in transparent glass curtain wall showed deviations within the range of ±10 mm and the overall median deviation was only 2 mm. Given the complex structural form of the cable net roof structure and the glass curtain wall system, 3D laser scanning demonstrated unparalleled efficiency as compared to the conventional measuring methods.

Evolution of the Reaction Front Shape and Structure on Flame Acceleration and Deflagration-to-Detonation Transition

Flame acceleration (FA) and the deflagration-to-detonation transition (DDT) are among the most interesting and exciting phenomena in the field of combustion and explosion of gases. From both practical and theoretical points of view, it is important to understand the basic laws governing these phenomena as well as the physical and/or chemical mechanisms and features of the process. High-speed flame-front photography during the deflagration of a premixed gas mixture in a long smooth tube with transparent walls was performed. A stoichiometric mixture of acetylene with oxygen diluted with argon by 25% is used. The experiments are carried out in a transparent cylindrical tube with an inner diameter of 60 mm and a length of 6 meters. The evolution of the structure and shape of the flame front from the moment of initiation of deflagration by a weak ignition source to the formation of a detonation wave is determined. Four characteristic phases of the propagation process are distinguished: at the first stage, the flame accelerates, then slows down, followed by flame propagation at an almost constant speed, and finally repeated acceleration, during which detonation is formed. It is shown how the dynamics of the process changes with a change in the initial pressure of the mixture. The most interesting and poorly studied stage of the DDT, the stage of intensive reacceleration, during which the flame abruptly changes shape, is described in detail.

Convection Heat Transfer from Heated Thin Cylinders Inside a Ventilated Enclosure

Experimental study was conducted to determine the effect of velocity of axial fan, outlet vent height, position, area, and aspect ratio (h/w) of ventilated enclosure on convection heat transfer. Rectangular wooden ventilated enclosure having top and front transparent wall was made up of Perspex for visualization, and internal physical dimensions of box were 200 mm × 200 mm × 400 mm. Inlet vent was at bottom while outlet vents were at the side and top wall. Electrically heated cylindrical heat source having 6.1 slenderness ratio was fabricated and hanged at the centre of the enclosure. To calculate heat transfer rates, thermocouples were attached to the inner surface of heat source with silica gel. Heat source was operated at constant heat flux in order to quantify the effect of velocity of air on heat transfer. It was observed that average Nusselt number was increased from 68 to 216 by changing velocity from 0 to 3.34 m/s at constant modified Grashof number i.e. 5.67E+09. While variation in outlet height at the front wall did not affect heat transfer in forced convection region. However, Nusselt number decreased to 5% by changing the outlet position from top to the front wall or by 50% reduction in outlet area during forced convection. Mean rise in temperature of enclosure increased from 8.19 K to 9.40 K by increasing aspect ratio of enclosure from 1.5 to 2 by operating heat source at constant heat flux i.e. 541.20 w/m2.

A novel approach for volumetric solar receiver performance assessments

A novel design and an efficient operation of solar volumetric receivers remain critical for successfully integrating such receivers into solar energy harvesting devices. The performance of the solar volumetric receiver is highly dependent on the geometric connectivity of the actual pore-sites in the SiC open-cell foams. Although the performance of SiC foam receivers has been investigated previously considering the homogeneous foam structure, further studies are needed to explore the influence of the actual path of the pores and their connectivity on the flow and thermal performance of the receiver. Hence, the present study considers the novel design of a solar volumetric absorber incorporating the actual SiC foam receiver geometric features. Accordingly, the thermal and flow behavior of the working fluid within the receiver is examined considering the 3D connectivity of the pore sites. Moreover, the performance of the solar volumetric receiver is evaluated for different Reynolds numbers, solar concentrations, and foam porosities. A 3D-dimensional numerical investigation is carried out incorporating the interactions between convection, conduction, and radiation heat transfer for which the discrete ordinate radiation model is used. Porous SiC foam is placed in a channel having an optically transparent wall at the top and air is used as the working fluid extracting heat from foam. The overall heat transfer coefficient, normalized Nusselt number, and thermal effectiveness are evaluated for various operating conditions. Findings revealed that the receiver thermal performance improves at high Reynolds numbers. The convection heat transfer is found to be the apparent heat transfer mode within the porous SiC foam. In addition, the pumping power to overcome the flow resistance in the channel is considerably less than that of the rate of heat transfer gain.

Energy-efficient design of building facade, inspired by human skin

A great amount of energy consumed is utilised to provide comfort in buildings. Windows (all transparent walls) are one of the factors for waste of energy. This study uses the characteristics of human skin as a protective layer and an interface between the inside and outside of the body to attempt to improve the performance of windows or transparent walls of a building facade. Simultaneously, the process of design and solving the problem is articulated, and the characteristics of human skin are discovered. Then, the traits of human skin are applied to enhance the diverse functions of building facades. Finally, from among more than 15 preliminary designs based on human skin characteristics, a vertical shading system is presented that can control the incoming radiation. The design is evaluated in two modes: controlled by temperature and by the intensity of sunlight. The results show that more than 10% of energy consumption is reduced with movable shading systems. An independent study of energy consumption for cooling, heating and lighting shows it is more reasonable to use the temperature-controlled shading system, which can save 23–25% of the annual cost of energy.