Search

The recycling of polymeric waste has attracted considerable interest and many efforts have been made to facilitate large scale recycling. The rapid evolution of technology has generated large volumes of obsolete and unusable polymeric products. One example is the CRT (cathode ray tubes) monitor that are rapidly being replaced by monitor types such as LCD, LED and Plasma. The present materials and routes for recycling this waste is not well known, which encourages studies in this area. The main objective of this work is to identify the type of polymer present in the CRT monitor frames and evaluate if the quality of the recycled polymer is changed according to the monitor age (year of manufacture). Monitors of different years of manufacture but the same brand were collected and disassembled. Frames were separated into two groups (older and younger). After, the frames were comminuted and samples were injected, according to ASTM D638-08. The samples were characterized by infrared, density, mechanical, MEV and TGA tests. The results obtained by infrared (FTIR) showed that regardless of the year of manufacture the monitor frames are produced with the same polymeric material, which was identified as copolymer ABS (acrylonitrile butadiene styrene). The results of mechanical and thermal tests showed that, in general, the recycled ABS polymers regardless of the year of manufacture showed no significant losses in their properties. However, it was found, by the TGA test, that there was a small variation in polymer composition. [ABSTRACT FROM AUTHOR]

Abstract: Along with the rapid increase in both production and use of TV sets in China, there is an increasing awareness of the environmental impacts related to the accelerating mass production, electricity use, and waste management of these sets. This paper aims to describe the application of life cycle assessment (LCA) to investigate the environmental performance of Chinese TV sets. An assessment of the TV set device (focusing on the Cathode Ray Tube (CRT) monitor) was carried out using a detailed modular LCA based on the international standards of the ISO 14040 series. The LCA was constructed using SimaPro software version 7.2 and expressed with the Eco-indicator’ 99 life cycle impact assessment method. For a sensitivity analysis of the overall LCA results, the CML method was used in order to estimate the influence of the choice of the assessment method on the results. Life cycle inventory information was compiled by Ecoinvent 2.2 databases, combined with literature and field investigations on the current Chinese situation. The established LCA study shows that the use stage of such devices has the highest environmental impact, followed by the manufacturing stage. In the manufacturing stage, the CRT and the Printed Circuit Board (PCB) are those components contributing the most environmental impacts. During the use phase, the environmental impacts are due entirely to the methods of electricity generation used to run them, since no other aspects were taken into account for this phase. The final processing step—the end-of-life stage—can lead to a clear environmental benefit when the TV sets are processed through the formal dismantling enterprises in China. [Copyright &y& Elsevier]

In this paper, a research that deals with the problem of determining of the visibility of the alphanumeric presentation on CRT and LCD screens is presented, in conditions when the screen filters are used, and when they are not used. A methodology that can be used for determination of the visibility of alphanumeric symbols on VDT screens is presented. It is determined the existence of differences in visibility of alphanumeric presentations when screen filters are used, compared to conditions when they are not used. This difference was statistically significant, while the visibility of the presented alphanumeric symbols on CRT and LCD screens that use screen filters is lower than when they are not used. For this reason, the use of protective screen filter is recommended in circumstances where a very high level of glare exists, when the visual fatigue is common appearance and when a user performs a task that does not depend on the detection of stimuli whose RGB values are low. [ABSTRACT FROM AUTHOR]

We demonstrate that cathode-ray-tube (CRT) monitors commonly used as stimulus generators in visual neuroscience produce signal artefacts. This arises from two factors, one being the finite time needed for the raster scan of the CRT to cross the receptive field being stimulated, and the other being the restraint imposed by the impulse response of the phosphor itself. Together these factors result in smearing or blurring that manifests as high frequency noise, distorting the desired signal applied by the investigator. Our analysis identifies those conditions that promote these artefacts and we describe methods for their minimisation. We suggest that a monitor frame rate ≥100 Hz provides a reasonable trade-off between refresh and the generators of high frequency noise. [Copyright &y& Elsevier]

Rationale and Objectives. The investigators developed an efficient method for optimizing cathode ray tube (CRT) monitor performance for digital mammography, based on the correlation between the performance of human observers and the performance of a mathematical computer model of the human visual system. The investigators examined observer performance on soft-copy display of mammographic images that were either unprocessed or processed to compensate for modulation transfer function (MTF) deficiencies in the CRT display. The results were used to validate the human visual system model.Materials and Methods. Six radiologists viewed a series of 250 mammographic images with microcalcification clusters with different contrast levels on a CRT monitor. The images were viewed twice: once without image processing and once with processing designed to compensate for MTF deficiencies in the CRT monitor. The images were analyzed with the JNDmetrix Visual Discrimination Model, which is based on the principles of just-noticeable difference measurement and frequency-channel vision modeling. Receiver operating characteristic (ROC) curves were generated for the human observers and compared statistically with the model observers’ performance.Results. Both human and model performance was better overall with the MTF-compensated images, especially for microcalcifications in the midlevel contrast range. There was a very high correlation between human and model observers.Conclusion. The use of image-processing methods to compensate for limitations in the MTF of CRT monitors can improve the detection performance of radiologists searching for microcalcifications in mammographic images, and a model based on characteristics of the human visual system can be used to predict human observer results accurately. [Copyright &y& Elsevier]

The dependence of the luminous output of computer-controlled CRT monitors on the digital colour values was measured on 11 different monitors. This dependence was called the channel function. Different settings of the monitors (gain/offset, position and size of the test colour patch, screen size) were investigated. It was concluded that the use of the default sRGB channel function instead of the measured channel function can lead to mean chromaticity errors of up to Δu′v′=0.06 and colour differences of up to ΔEab*=33. Changing the graphics card did not influence the channel functions significantly. [Copyright &y& Elsevier]