Effect of biological factors on latency of pattern-reversal visual evoked potentials associated with cathode ray tubes and liquid crystal display monitors in normal young subjects.

PURPOSE: Owing to several factors, peak latencies of pattern-reversal visual evoked potentials (p-VEP) are delayed when viewing liquid crystal display (LCD) monitors compared to those evoked when viewing cathode ray tube (CRT) monitors. However, few studies have examined whether biological factors affect latency in LCD. This study aimed to investigate whether biological factors caused latency changes in LCD among young subjects. METHODS: Twenty-eight subjects (56 eyes) aged 21-29 years (mean ± SD, 22.7 ± 1.7) participated in this study. We recorded output from each eye twice for both CRT and LCD monitors under the same conditions for monocular p-VEP. The peak latencies of three components (N75, P100, and N145) were compared between these two monitors. RESULTS: All peak latencies recorded with LCD were delayed compared to those recorded with CRT: N75, 9.7 ± 2.5 ms; P100, 10.1 ± 3.0 ms; and N145, 8.4 ± 6.2 ms (all p < 0.001). The degree of latency delay varied depending on the components. Moreover, all peak latencies of CRT appeared earlier than standard values of N75, P100, and N145. CONCLUSIONS: These findings suggest that the following aspects should be considered when assessing biological factors that may affect latency: components might influence latency changes; a young age could be related to an early appearance of peak latencies; inter-individual differences might cause latency change. These biological factors should be considered as possible causes for the varying latencies in an LCD monitor. Further studies should include healthy adults with a wider age range to assess the effects of age on latency.

Entrainment within neuronal response in optic tectum of pigeon to video displays.

The cathode ray tube (CRT) is a common and important tool that has been in use for decades, with which behavioral and visual neuroscientists deliver specific visual images generated by computers. Considering the operating principle of the CRT, the image it presents can flick at a constant rate, which will introduce distractions to the visual experiments on subjects with higher temporal resolutions. While this entrainment has been proved common in recordings of the primary visual cortex of mammals, it is uncertain whether it also exists in the intermediate to deep layers of pigeon's optic tectum, which is relevant to the spatial attention. Here, we present continuous visual stimuli with different refresh rates and luminances couples shown on a CRT to pigeons. The recordings in the intermediate to deep layers of optic tectum were significantly phase locking to the refresh of the CRT, and lower refresh rates of the CRT with higher brightness more likely introduced artifacts in electrophysiological recordings of pigeons, which may seriously damage their visual information perception.

Novel indicators to better monitor the collection and recovery of (critical) raw materials in WEEE: Focus on screens.

Currently, in the European Union (EU), e-waste chain performance is assessed by technical indicators that aim to ensure system compliance with collection and recovery targets set by the WEEE Directive. This study proposes indicators to improve WEEE flow monitoring beyond the current overall weight-based approach, including complementary flows and treatment performance. A case study focused on the screen category in France is presented. In 2017, the collection rate of cathode-ray tube screens (CRT) was 68%, while for flat panel display (FPD) generated only 14% was collected. CRT screens have less precious and critical materials than FDP. Thus, elements like cobalt and gold highly concentrated in FPD, have a collection rate two to four times lower than elements such as copper (37%) which represents a high proportion in CRTs. Recycling is the main treatment in France. Nevertheless, the recycling rate per element varies significantly due to the low collection, and also the lack of technology and/or secondary raw materials market. The elements with higher recycling rates are base metals such as copper (28%), followed by precious metals like silver (23%), and gold (13%). Except for palladium, the recycling rate of the critical raw materials targeted in the study ranged from 6% (cobalt) to 0% (e.g. neodymium and indium). The results stress the need for indicators to support the development of WEEE chain from waste management to secondary (critical) raw materials suppliers.

Uncovering material flow analysis of waste cathode ray tubes television in China.

Cathode ray tube televisions (TVs) contributes significantly to the rapidly increasing waste stream of cathode ray tubes in the e-waste. This study mainly focused on the material flow of waste cathode ray tube TVs in China. Currently, waste cathode ray tubes constitute a major part of the total generation of e-waste in China. The study aimed to emphasise the flow of materials in the generated waste cathode ray tube TVs by using stock-based material flow analysis model. The modelling was conducted to investigate the disposable number of obsolete devices, in-use stock, and end-of-life of cathode ray tube TVs. SubSTance flow ANalysis (STAN) software was used to perform the material flow analysis modelling and graphical model of the waste cathode ray tube TVs. The results show that in a period of 10 years, overall about 3241.37 kt of cathode ray tube TVs were net produced in China, containing 183.6 kt of glass, 1718.2 kt of plastic, 243 kt of steel/iron, 153.5 kt of lead, 76.6 kt of copper, 7.8 kt of aluminium, and 1.6 kt of antimony. The results revealed that almost 125 kt of end-of-life cathode ray tube TVs containing about 68 kt of glass, 40 kt of plastic, 9 kt of steel/iron, 6 kt of lead, 3 kt of copper, 0.3 kt of aluminium, and 0.07 kt of antimony were dumped in the period of 10 years. Therefore, the management of waste cathode ray tube TVs required better infrastructure for recycling and better regulation to achieve better results in the high recovery of valuable resources.

Ease of disassembly of products to support circular economy strategies.

Circular economy strategies encourage, among others, concrete actions to extend the product lifetime. Product's repair and reuse, and component harvesting for reuse, all require the facilitated access to product components. Consequently, a reduction of the disassembly time and the related costs will increase the economic feasibility of product lifetime extension and therefore increase the viability of a circular economy in industrialised regions. Furthermore, disassembly has the potential to significantly increase the recycling yield and purity for precious metals, critical metals and plastics. For this reason, the European Commission and several ecolabels have considered to include design for disassembly requirements in legislation or voluntary environmental instruments. However, up to date, there is no standardised method to evaluate the ease of disassembly in an unambiguous manner with a good trade-off between the efforts required to apply the method and the accuracy of the determined disassembly time. The article proposes a robust method "eDiM" (ease of Disassembly Metric), to calculate the disassembly time based on the Maynard operation sequence technique (MOST). A straightforward calculation sheet is employed in eDiM to calculate the disassembly time given the sequence of actions and basic product information. This makes the results fully verifiable in an unambiguous manner, which makes eDiM suited to be used in policy measures in contrast to the results of prior developed methods One of the innovative aspects of eDiM is the categorization of disassembly tasks in six categories, which provides better insights on which disassembly tasks are the most time consuming and how the product design could be improved. The proposed method is illustrated by means of a case study of an LCD monitor. The presented case study demonstrates how the proposed method can be used in a policy context and how the calculated disassembly times per category can provide insights to manufacturers to improve the disassemblability of their products. The results also demonstrate how the proposed method can produce realistic results with only limited detail of input data.

Lead waste glasses management: Chemical pretreatment for use in cementitious composites.

This article investigates the effect of a low-impact chemical treatment based on a nitrilotriacetic acid chelating agent on the reactivity of funnel glass derived from discarded cathode ray tubes. Treated and untreated glass has been recycled either as a supplementary cementing material or as a fine aggregate in cementitious mortars. The effect of the treatment on the chemical and morphological properties of cullets, as well as on the solubility in an alkaline environment has been evaluated. Data so far collected underline a change in glass cullets characteristics that consequently affects their behaviour in cementitious mortars, reducing the pozzolanic activity as supplementary cementing material, but strongly decreasing the tendency towards alkali silica reactions when added as a fine aggregate. The leaching behaviour of lead on treated and untreated glass and on derived composites has been determined to verify the sustainability of the prepared materials.

Effect of varying CRT refresh rate on the measurement of temporal summation.

PURPOSE: To quantify the effect of cathode-tube-ray (CRT) monitor refresh rate on the measurement of the upper limit of complete temporal summation (critical duration) in the peripheral visual field of healthy observers. METHODS: Contrast thresholds were measured for seven achromatic spot stimuli (diameter 0.48°) of varying duration (nominal values: 10-200 ms) at an eccentricity of 8.8° along the 45°, 135°, 225° and 315° meridians of the visual field in three healthy, psychophysically experienced observers. Stimuli were presented on a CRT display with a refresh rate of 60 and 160 Hz. Contrast thresholds were expressed as contrast energy with stimulus durations being estimated using (1) the sum-of-frames (SOF) method and (2) Bridgeman's method incorporating measurements of phosphor persistence. Estimates of the critical duration were produced using iterative two-phase regression analysis. RESULTS: With stimulus duration expressed as SOF equivalent the critical duration was, on average, 10.6 ms longer with a refresh rate of 60 Hz (mean 45.7 ms, S.D. 10.1 ms) relative to 160 Hz (35.1 ms, S.D. 7.6 ms). When the Bridgeman method was used, minimal differences (1.8 ms) in critical duration values between the two refresh rates (60 Hz: 33.0 ms, S.D. 9.4 ms; 160 Hz: 31.2 ms, S.D. 7.0 ms) were observed. Identical trends were observed in all three subjects. CONCLUSIONS: Psychophysical measurements of temporal summation are independent of variations in CRT refresh rate when the Bridgeman method, incorporating measured values of phosphor persistence, is used to estimate stimulus duration. This has significant implications for the specification of stimulus duration in psychophysical studies of vision employing conventional display monitors.

Lead recovery from scrap cathode ray tube funnel glass by hydrothermal sulphidisation.

This research focused on the application of the hydrothermal sulphidisation method to separate lead from scrap cathode ray tube funnel glass. Prior to hydrothermal treatment, the cathode ray tube funnel glass was pretreated by mechanical activation. Under hydrothermal conditions, hydroxyl ions (OH(-)) were generated through an ion exchange reaction between metal ions in mechanically activated funnel glass and water, to accelerate sulphur disproportionation; no additional alkaline compound was needed. Lead contained in funnel glass was converted to lead sulphide with high efficiency. Temperature had a significant effect on the sulphidisation rate of lead in funnel glass, which increased from 25% to 90% as the temperature increased from 100 °C to 300 °C. A sulphidisation rate of 100% was achieved at a duration of 8 h at 300 °C. This process of mechanical activation and hydrothermal sulphidisation is efficient and promising for the treatment of leaded glass.

Management practices for end-of-life cathode ray tube glass: Review of advances in recycling and best available technologies.

Cathode ray tubes are image display units found in computer monitors and televisions. In recent years, cathode ray tubes have been generated as waste owing to the introduction of newer and advanced technologies in image displays, such as liquid crystal displays and high definition televisions, among others. Generation and subsequent disposal of end-of-life cathode ray tubes presents a challenge owing to increasing volumes and high lead content embedded in the funnel and neck sections of the glass. Disposal in landfills and open dumping are anti-environmental practices considering the large-scale contamination of environmental media by the potential of toxic metals leaching from glass. Mitigating such environmental contamination will require sound management strategies that are environmentally friendly and economically feasible. This review covers existing and emerging management practices for end-of-life cathode ray tubes. An in-depth analysis of available technologies (glass smelting, detoxification of cathode ray tube glass, lead extraction from cathode ray tube glass) revealed that most of the techniques are environmentally friendly, but are largely confined to either laboratory scale, or are often limited owing to high cost to mount, or generate secondary pollutants, while a closed-looped method is antiquated. However, recycling in cementitious systems (cement mortar and concrete) gives an added advantage in terms of quantity of recyclable cathode ray tube glass at a given time, with minimal environmental and economic implications. With significant quantity of waste cathode ray tube glass being generated globally, cementitious systems could be economically and environmentally acceptable as a sound management practice for cathode ray tube glass, where other technologies may not be applicable.

What monitor can replace the cathode-ray tube for visual stimulation to elicit multifocal electroretinograms?

To compare a conventional cathode-ray tube (CRT) screen to organic light-emitting diode (OLED) and liquid crystal display (LCD) screens as visual stimulators to elicit multifocal electroretinograms (mfERGs), mfERGs were recorded from seven eyes of seven healthy volunteers (21 ± 2 years). The mfERGs elicited by a conventional CRT screen (S710, Compaq Computer Co.) were compared to those elicited by a studio-grade master OLED monitor (PVM-1741, Sony, Japan) and a conventional LCD (S1721, Flexscan, Eizo Nanao Corp., Japan). The luminance changes of each monitor were measured with a photodiode. CRT, OLED, and LCD screens with a frame frequency of 60 Hz were studied. A hexagonal stimulus array with 61 stimulus elements was created on each monitor. The serial white stimuli of the OLED screen at 60 Hz did not fuse, and that of the LCD screens fused. The amplitudes of P1 and P2 of the first-order kernels of the mfERGs were not significantly different from those elicited by the CRT and OLED screens, and the P1 amplitude of the first-order kernel elicited by the LCD stimuli was significantly smaller than that elicited by the CRT in all the groups of the averaged hexagonal elements. The implicit times were approximately 10 ms longer in almost all components elicited by the LCD screen compared to those elicited by the CRT screen. The mfERGs elicited by monitors other than the CRT should be carefully interpreted, especially those elicited by LCD screens. The OLED had good performance, and we conclude that it can replace the CRT as a stimulator for mfERGs; however, a collection of normative data is recommended.

Evaluation of lead recovery efficiency from waste CRT funnel glass by chlorinating volatilization process.

The current study was carried out to develop a novel process, namely chloride volatilization procedure for lead recovery from waste cathode ray tube (CRT) funnel glass. In the recovery system, the glass powder was first compressed into cylindrical pellet homogeneously with chlorinating agents, and then subjected to thermal treatment for solid-phase reaction. In this case, lead could be easily released from the silicon oxide network of the glass and it was recovered in the form of PbCl2. It was found that CaCl2 was the most effective chlorinating agent, and the optimum operation temperature, holding time and system pressure were 1000 °C, 2 h, 600 ± 50 Pa, respectively. The evaporated PbCl2could be easily recovered by a cooling device. The evaporation ratio of lead from waste CRT was 99.1% and the purity of the recovered PbCl2product was 97.0%. The reaction routes and lead recovery mechanisms of the process were identified. This study provides an efficient and practical process for waste CRT funnel glass detoxification and recycling.

Decoding facial blends of emotion: visual field, attentional and hemispheric biases.

Most clinical research assumes that modulation of facial expressions is lateralized predominantly across the right-left hemiface. However, social psychological research suggests that facial expressions are organized predominantly across the upper-lower face. Because humans learn to cognitively control facial expression for social purposes, the lower face may display a false emotion, typically a smile, to enable approach behavior. In contrast, the upper face may leak a person's true feeling state by producing a brief facial blend of emotion, i.e. a different emotion on the upper versus lower face. Previous studies from our laboratory have shown that upper facial emotions are processed preferentially by the right hemisphere under conditions of directed attention if facial blends of emotion are presented tachistoscopically to the mid left and right visual fields. This paper explores how facial blends are processed within the four visual quadrants. The results, combined with our previous research, demonstrate that lower more so than upper facial emotions are perceived best when presented to the viewer's left and right visual fields just above the horizontal axis. Upper facial emotions are perceived best when presented to the viewer's left visual field just above the horizontal axis under conditions of directed attention. Thus, by gazing at a person's left ear, which also avoids the social stigma of eye-to-eye contact, one's ability to decode facial expressions should be enhanced.

Use of limestone powder during incorporation of Pb-containing cathode ray tube waste in self-compacting concrete.

For several decades, cathode ray tubes (CRTs) were the primary display component of televisions and computers. The CRT glass envelope contains sufficient levels of lead oxide (PbO) to be considered hazardous, and there is a need for effective methods of permanently encapsulating this material during waste disposal. We examined the effect of adding limestone powder (LS) on the fresh and cured properties of self-compacting concrete (SCC) mixtures containing waste CRT glass. The SCC mixtures were prepared using Type 1 Portland cement at a constant cement content of 600 kg/m(3) and a water-to-cement ratio (w/c) of 0.38. CRT glass waste cullet was blended with river sand in proportions of 20 or 40% by weight. To suppress potential viscosity effects limestone powder was added at levels of 5, 10, or 15% by weight. The slump flow time, slump flow diameter, V-funnel flow time, Marsh cone flow time, and setting time of the fresh concrete were tested, as well as the compressive strength and ultrasonic pulse velocity of the hardened concrete. Addition of limestone powder improved the fresh and hardened properties. Pb leaching levels from the cured concrete were within US EPA allowable limits.

Recovering lead from cathode ray tube funnel glass by mechano-chemical extraction in alkaline solution.

This study evaluates the efficiency of lead (Pb) extraction from cathode ray tube (CRT) funnel glass in strongly alkaline solution using mechanical activation in a ball mill as the chemical breakage and defects formed in the inner structures will contribute to the easy dissolution of the activated Pb glass. The combination of mechanical activation and a chemical leaching process in a single operation (mechano-chemical leaching) is more effective than the mechanical activation and subsequent chemical leaching. More than 97% of Pb in the CRT funnel glass can be extracted with a stirring ball mill leaching process in 5 M sodium hydroxide at 70°C. The diameter of the stainless steel balls as the activation medium is 5 mm; the mass ratio of ball to raw materials is 25:1. Pb powder with a purity of 97% can be obtained by electrowinning from the leaching solution. The Pb-depleted solution can be recycled into the leaching step. After Pb is removed, the solid leaching residues can be used for preparation of foam glass. Thus, a novel hydrometallurgical process for recovering Pb from CRT funnel glass in alkaline solution is proposed.

Green Conversion of the Hazardous Cathode Ray Tube and Red Mud into Radiation Shielding Concrete.

The present investigation was aimed at the utilization of alternate materials, emphasizing hazardous industrial products (red mud and cathode ray tubes), as constituents of radiation shielding concrete. The usage of these hazardous industrial products improves the sustainability and performance of the radiation shielding concrete. Five concrete blocks were cast and their density, compressive strength, gamma shielding factors, radiation absorption ratio, and transmission factor were explored. For this purpose, gamma-ray shielding measurements were done with the help of an HPGe detector. Mix-1, with zero contents of red mud and CRTs, had the lowest LAC. The LAC results demonstrated that the shielding performance of the current concretes would be better with the increase in red mud and cathode ray tube glass. The Transmission factor (TF) for the prepared concretes with a thickness of 2 cm varied between 11.9-26.1% at 0.06 MeV, while it varied between 4-13% for a thickness of 3 cm. The TF results showed that the composites with a thickness of 2, 3, or 5 cm are good shields against lower energy radiation. The radiation absorption ratio (RAR) for the prepared concretes is high at low energy, suggesting that these new composites can absorb most of the low-energy photons. The RAR results emphasize that the increase in CRTs in the new composites enhanced the radiation shielding features, and when the CRT glass is at a maximum, more attenuation was achieved.

Potential for Use of Recycled Cathode Ray Tube Glass in Making Concrete Blocks and Paving Flags.

The potential to use waste glass, including cathode ray tube (CRT) glass, for making new products or as an admixture to existing ones is being intensively investigated. This kind of research intensified particularly in the period after CRT TV sets and computer monitors were replaced in the market by the advanced technology of thin film transistor (TFT) and liquid crystal display (LCD) screens. Cathode ray tube glass represents a considerable part of electronic waste (e-waste). E-waste globally increases at a far higher rate than other solid waste materials. There is a possibility to recycle cathode ray tube glass and use it in the construction industry. This paper shows the test results of physical and mechanical properties of blocks and paving flags. The reference specimen was made with quartz sand, while the other product employed a combination of quartz sand and ground panel cathode ray tube glass. The glass was ground to the fraction 0.25/1.00 mm, which corresponds to quartz sand fineness. The following tests were performed: shape and dimensions, resistance to freeze/thaw and de-icing salts, water absorption, splitting tensile strength and tensile strength by bending. Special attention was paid to the tests of Böhme wear resistance, slip resistance of the top surface of CRT products using a pendulum, radioactivity and leaching. The texture of the experimental concrete products was observed by SEM (scanning electron microscopy) and analyzed. The results obtained by experimental testing unequivocally show that CRT glass can successfully be used for making concrete blocks and paving flags.

Chemical-Electrochemical Process Concept for Lead Recovery from Waste Cathode Ray Tube Glass.

This paper presents a novel approach for the recovery of lead from waste cathode-ray tube (CRT) glass by applying a combined chemical-electrochemical process which allows the simultaneous recovery of Pb from waste CRT glass and electrochemical regeneration of the leaching agent. The optimal operating conditions were identified based on the influence of leaching agent concentration, recirculation flow rate and current density on the main technical performance indicators. The experimental results demonstrate that the process is the most efficient at 0.6 M acetic acid concentration, flow rate of 45 mL/min and current density of 4 mA/cm2. The mass balance data corresponding to the recycling of 10 kg/h waste CRT glass in the identified optimal operating conditions was used for the environmental assessment of the process. The General Effect Indices (GEIs), obtained through the Biwer Heinzle method for the input and output streams of the process, indicate that the developed recovery process not only achieve a complete recovery of lead but it is eco-friendly as well.

Durability Properties of Concrete Supplemented with Recycled CRT Glass as Cementitious Material.

This paper presents the testing of the durability of concrete where a part of cement was replaced with ground panel cathode ray tube glass (CRT) finer than 63 µm. The percentage of cement replaced with glass is 5%, 10%, 15%, 20%, and 35%, by mass. The highest percent share of mineral admixtures in CEM II (Portland-composiste cement) cement was chosen as the top limit of replacement of cement with glass. In terms of the concrete durability, the following tests are performed: freeze-thaw resistance, freeze-thaw resistance with de-icing salts-scaling, resistance to wear according to the Böhme test, sulfate attack resistance, and resistance to penetration of water under pressure. A compressive strength test is performed, and shrinkage of concrete is monitored. In order to determine the microstructure of concrete, SEM (Scanning Electron Microscopy) and EDS (Energy Dispersive X-ray Spectroscopy) analyses were performed. The obtained research results indicate that the replacement of a part of cement with finely ground CRT glass up to 15% by mass has a positive effect on the compressive strength of concrete in terms of its increase without compromising the durability of concrete. The results obtained by experimental testing unequivocally show that concrete mixtures made with partial replacement (up to 15%) of cement with finely ground CRT glass have the same freeze-thaw resistance, resistance to freeze/thaw with de-icing salt, resistance to wear by abrasion, and resistance to sulfate attack as the reference concrete. In terms of environmental protection, the use of CRT glass as a component for making concrete is also very significant.

Feasible Use of Cathode Ray Tube Glass (CRT) and Recycled Aggregates as Unbound and Cement-Treated Granular Materials for Road Sub-Bases.

In the last 15 years, new types of display technologies have increasingly replaced cathode ray tube (CRT) screens, which has led to an increase in landfill of old discarded CRT televisions, which present a great environmental challenge throughout the world due to their high lead content. In addition, environmental awareness has led to greater use of recycled aggregates to reduce the exploitation of existing reserves. This document aims to study the feasibility of incorporating CRT glass waste with recycled aggregate (RA) in combinations for use in civil engineering, more specifically in road bases and sub-bases. For the mechanical and environmental assessment of all of the samples and materials, the following procedures have been performed: the compliance batch test of UNE-EN 12457-4:2004 for RA, CRT, and mixtures; the Percolation Test according CEN/TS 14405 for the mixtures, CRT, and RA; Modified Proctor and load capacity (the California Bearing Ratio, or CBR) in all mixtures without cement addition, and finally, compressive strength of the material treated with cement at different ages of curing. The analysis of the mechanical and environmental properties through different techniques of lixiviation was positive, showing the ability to use CRT for certain dosage percentages mixed with recycled aggregates.

Development of a novel recycling system for waste cathode ray tube funnel glass based on the integration of nanoscale Fe0 with ball milling.

A novel and effective system was developed for recycling cathode ray tube (CRT) funnel glass wastes. Initially, the combination of nanoscale Fe0 with ball milling promoted lead transfer that was strongly encapsulated in the glass inner structure to the surface of funnel glass and/or adhere to iron substance due to the collapse of SiO bonds. This condition enhanced the dissolution of lead in the acid solution. A high lead extraction rate of 97.8% from funnel glass was achieved through nitric acid leaching by optimizing the operational parameters (Fe0/funnel glass mass ratio, 0.5:1; ball milling time; 72 h). Subsequently, lead sulfate, iron hydroxides, and sodium nitrate were gradually recovered from the acid leachate by using three simple operations, namely, sulfation, alkali neutralization, and salt evaporation. Meanwhile, the leaching results of short-term toxicity characteristic leaching (TCLP) and long-term multiple extraction procedures (MEP) clearly demonstrated that the residual high silica products (after acid leaching) had no impact on the environment and could be used to synthesize high value-added zeolites as raw materials. With the addition of Al sources, the complete conversion of high silica residues into high crystalline zeolites with high cation exchange capacity value was realized by applying an alkaline fusion method during the hydrothermal treatment. Furthermore, lead, NO-3, and SO2-4 concentrations of the resulting drainage were considerably lower than the relevant standard for surface water quality. Therefore, the proposed recycling system provided an eco-friendly and feasible technique for complete reutilization of obsolete CRT funnel glass.