Ray Tube Research Articles

Recycling E-waste CRT glass in sustainable geopolymer concrete for radiation shielding applications

Waste cathode ray tube (CRT) glass, enriched with heavy metal of Pb, is classified as hazardous waste and needs to be disposed of harmlessly. This study recycles waste CRT glass as heavy aggregate in sustainable geopolymer concretes (GCs) to enhance its γ-ray shielding performance. It also comprehensively evaluates its macro-performances, microstructure, and environmental and economic impacts. The results demonstrate that the compressive strength of GCs decreases with the dosage of CRT glass. The generation of geopolymer gel is hindered by excessive CRT glass. Besides, the compatibility between CRT glass and the geopolymer matrix is poor. Both factors influence the strength development of CRT glass-incorporated GCs. The compressive strength of GCs with 50 % CRT glass aggregate exceeds 30 MPa, meeting the requirements for building materials. Due to the increase in the density and the introduction of heavy nuclei Pb, the γ-ray shielding performance of GCs is 9 % higher than that of normal concrete. In terms of economic and environmental benefits, this approach realizes the value-added recycling of CRT glass, avoiding the disposal cost of CRT glass. Besides, due to the utilization of sustainable geopolymer as cementitious materials, the carbon footprint of designed CRT glass-enhanced radiation shielding GCs is even 34 % lower than that of normal concrete. This study highlights the advantages of geopolymer and CRT glass in developing sustainable radiation shielding materials for nuclear technology and medicine fields.

Recycling and optimum utilization of CRT glass as building materials: An application of low CO2 based circular economy for sustainable construction

The construction industry is the major contributor of CO2 emission around the globe. The rapid advances in the electronics industry have transformed the disposal of cathode ray tube glass waste (CRT-WG) into a prominent environmental concern. Recycling of CRT glasses as building materials can help in the production of sustainable construction. Numerous previous studies have documented that CRT-WG can be utilized either as a component of fine aggregate or binder material as it provides a cleaner solution and reduce carbon emission. Under this cleaner production and low CO2 emission perspective, this paper provides a thorough review of the previous studies on the utilization of CRT glass as a partially and fully substitute of sand and cementitious material in mortar production and propose an application of CO2 based circular economy model for reduce carbon emissions. This paper summarized the fresh, mechanical and durability properties of mortar incorporating treated and un-treated CRT-WG with different mineral additives and w/b ratios. Furthermore, this research explores the optimal proportions of CRT glass that can be use as replacements for sand and cement powder to make eco-friendly and sustainable low carbon mortar suitable for both structural and non-structural applications. More particularly, this review emphasizes the benefits, the need for additional research, and the drawbacks of CRT-WG use in construction building. Overall, this study proposes that incorporating CRT glass into building materials through a low CO2 based circular economy offers significant potential advantages. This study will help in optimization of CRT glass in concrete mix design in combination with waste materials for sustainable construction.

Production of Autoclaved Cementitious Composites Using Recycled Waste Glass

ABSTRACTOne of the major negative environmental implications of economic growth and the advancement of information technology is the large quantity of electronic waste dumped in landfills. Cathode ray tubes (CRTs) from outdated televisions and computer monitors are a significant source of electrical waste. The CRT funnel primarily consists of silica, significant alkalis (Na2O‐K2O), and heavy metals like barium‐strontium, along with a substantial lead (Pb) content that may contaminate the soil. Owing to its heavy metal content, CRT is considered hazardous waste, and regulations require its glass to be recycled or repurposed instead of landfill disposal. The low pozzolanic activity of CRT silica suggests that its high content, when paired with an optimized particle size and specific curing conditions, can enhance the mechanical properties of cement‐based products. Hydrothermal treatment has been found to speed up both the hydration of ordinary Portland cement (OPC) and the pozzolanic reactions. Since the main objective was to safely recycle large amounts of CRT, three mixes were proposed with 10%, 20%, and 30% OPC + 90%, 80%, and 70% CRT, respectively, and the effect of hydrothermal curing conditions on mechanical properties and durability of these blends was investigated. CRT‐70, a blend containing 70% CRT glass waste, showed enhanced strength due to the formation of zeolitic phases and calcium silicate hydrate (CSH). These phases also provided CRT‐70 with notable fire resistance, ensuring its structural stability under elevated temperatures. These results demonstrate the possibility of production of precast building products via high‐volume recycling of hazardous CRT waste.

AC thin-film electroluminescence: A historical overview with a look ahead

50 years ago, television screens used bulky cathode ray tubes (CRTs) with a size limited to about 70 cm in diagonal (28 in.), while flat panel displays belonged to the realm of science fiction. Although the performance of CRTs in terms of energy consumption, size, and color rendering slowly improved, there were numerous applications where flat panel displays would present a tremendous advantage, notably for confined spaces and in portable equipment. Starting from the 1970s, AC thin-film electroluminescence (ACTFEL) was investigated as a high performance alternative to the—also emerging—liquid crystal displays (LCDs) and plasma display panels (PDPs). For a number of years, ACTFEL developed from the phase of fundamental research to commercial products (for monochrome displays) and full color prototype displays. However, due to the fast development and strong cost reduction of LCDs, ACTFEL did not remain competitive and most of the research activities were ceased. The current overview sketches a brief history of the ACTFEL technology, its merits and limitations, and the reasons why such displays still have their use in some niche applications.

Research on wireless channel model based on improved ray tracing algorithm that considers multiple diffuse scattering and employs pyramid-shaped ray tubes as the carrier

This paper extensively utilizes fine three dimensional environmental data obtained from laser point clouds. Based on theories such as geometrical optics and effective roughness theory, a deterministic wireless channel model is established, which integrates higher-order diffuse scattering. This model is referred to as the ray tracing fusion with higher-order diffuse scattering model. To expedite the collision calculation between rays and the scene, this paper introduces a combined approach of voxelization and signed distance field, resulting in a remarkable 16-fold improvement in computational speed. Moreover, aiming to balance accuracy and efficiency, the paper systematically analyzes the optimization computation parameters of the model. Finally, the proposed model is validated using measurement data in the frequency range of 1 GHz to 6 GHz in mountainous terrain. The results indicate that the predicted outcomes of the proposed model have an accuracy within 6 dB compared to the measurement results, and are superior to ITU-R P.1546, which is an international standard recommended by the International Telecommunication Union for modeling electromagnetic wave propagation in undulating terrain. This provides necessary technical support for network planning and optimization.

Production of lightweight geopolymer concrete with foam glass aggregate derived from cathode-ray glass waste

This work focused on producing an eco-friendly lightweight structure by recycling the cathode ray tube glass waste (CRT-GW)to prepare a foam glass aggregate (FGA) and using metakaolin to prepare a geopolymer binder (GP). The geopolymer binder replaces cement to decrease the release of gas generated during cement production. The silicon carbide (SiC) was used as a foaming agent at 1 wt% to prepare the FGA. The foaming temperature effect was investigated for the FGA characterization included: bulk density, volume expansion, apparent porosity, uniaxial compressive strength, and leaching tests for lead and barium. The foam glass aggregate was sintered at different temperatures 725 °C, 750 °C, 775 °C, and 800 °C. These temperatures were selected depending on heating microscopy analysis results, where the maximum expansion height was 119 % at 800 °C. The main characterization ranges of foam glass were: bulk density 0.58–1.26 g/cm3, volume expansion 8–77 (vol%), uniaxial compressive strengths 1.55–9.98 MPa, and thermal conductivity 0.063–0.097 W/m.K.The lightweight geopolymer (LWGP) was prepared with 30 vol% of FGA sintered at different temperatures and 70 vol% of GP. These samples hardened at room temperature. The bulk density and compressive strength were measured for the lightweight geopolymer samples after a curing time of 28 days. A higher compressive strength was 9.11 MPa with a bulk density of 1.21 g/cm3 for lightweight geopolymer-containing foam glass aggregate sintered at 775 °C.

X- and gamma rays cross sections and nuclear shielding performance of recycled cathode ray tube doping with high concentrations of Na2CO3

In an attempt to mitigate the increasing number of waste Cathod Ray Tube (CRT) glass in the environment, provide a safe, cheaper, and environmentally attractive recycling route for the glasses, and provide an alternative material for gamma radiation absorption applications, this study investigated the influence of adding Na2CO3 on the density, and gamma photon-absorbing prowess of CRT glass. Using the powder metallurgy process, CRT-NCx glasses consisting of CRT glass powder mixed with two distinct weight concentrations (20% (CRT-NC20 and 40% (CRT-NC40)) of Na2CO3 powder were prepared. The mass attenuation coefficients (μρ) of the prepared glasses were obtained using FLUKA simulations for 15 keV–15 MeV photons. The density of CRT, CRT-NC20, and CRT-NC40 were 3.117 g/cm3, 2.987 g/cm3, and 2.894 g/cm3, respectively. The range of μρ for CRT, CRT-NC20, and CRT-NC40 corresponded to 0.0326–45.5236 cm2/g, 0.030–35.0662 cm2/g, and 0.0278–26.9813 cm2/g, respectively. The half-value layer and mean free path was found to vary within the range 0.005–6.822 cm and 0.007–9.842 cm for CRT; 0.007–7.748 cm and 0.010–11.178 cm for CRT-NC20; and 0.009–8.633 cm and 0.013–12.455 cm for CRT-NC40. The minimum and maximum values of μenρ were 0.0216 and 37.7566 cm2/g for CRT, 0.0202 and 29.1167 cm2/g for CRT-NC20, and 0.01921 and 22.4430 cm2/g for CRT-NC40. CRT-rich glass showed higher radiation absorbed doses for the same beam energy and glass thickness. Na2CO3-rich glasses had lower buildup factors BFs, hence preferable in broad beam transmission scenarios. The investigated CRT-NCx glasses are more attractive for radiation protection functions in contrast to some well-known radiation shielding materials considering their lower mean free paths. The present glass system provides and alternative and effective gamma radiation shield, and also proffers a way of upcycling waste CRT glasses.

Research on channel modeling technology of visible light communication system based on the ray tracing method

Abstract Visible Light Communication (VLC) is a new mode that combines lighting and communication. Because it can meet the needs of large capacity and ultra-high transmission rate, effective analysis of indoor visible light channel characteristics can better provide VLC systems. We provide a reference basis for the design, and VLC technology using Light Emitting Diode (LED) as the light source has become one of the research hotspots in the field of wireless communications. To solve the problems of existing indoor visible light channel modeling methods such as being ideal, high complexity, or poor in versatility, this paper researches indoor visible light communication channel modeling and related theories and methods, using rays with strong scene adaptability. Based on the tracking method, starting from the need to reduce computational complexity and improve tracking accuracy, a channel modeling method for indoor visible light communication is designed. We propose a high-precision indoor visible light communication channel modeling method that combines central ray tubes and bidirectional ray tracing. We use the forward ray tracing method to model indoor visible light communication channels. The simulation experimental results show that the channel modeling method proposed in this article can effectively improve modeling efficiency.

Effect of microstructure on the physicochemical characteristics of foam glass made by soda lime -CRT glasses and aluminium dross

Foam glass, an inorganic insulation material, is primarily manufactured from recycled glass or sand combined with a foaming agent. During fabrication, gas bubbles are generated in the softened glass, causing it to expand and form a cellular structure. Critical parameters such as cell size, type (closed or open cells), distribution, and uniformity significantly influence the physical and chemical properties of foam glass, ensuring sustained thermal efficiency. This research aims to produce foam glass exclusively from waste materials, thereby promoting the circular economy by utilizing container glass, cathode ray tube (CRT) glass, and aluminium dross. A comprehensive microstructural analysis, employing computer tomography and scanning electron microscopy, elucidated key properties including density, thermal conductivity, and water absorption. The manufactured foam glass exhibited lightweight characteristics, with a density ranging from 0.15 to 0.18 g/cm³. Additionally, the foam glass demonstrated low thermal conductivity (between 0.038 W/m·K and 0.05 W/m·K), which can be attributed to the heterogeneous distribution of cells that effectively reduce heat convection. This property makes foam glass an excellent thermal insulator. Furthermore, both high-absorption (open porosity) and low-absorption (closed porosity) foam glasses were successfully produced.

Derivation of Glaze from Cathode Ray Tubes (CRTs) for Ceramic Wares

Introduction of digital display makes cathode ray tube to be largely obsolete. The tube with its screen becomes waste at the end of the products lifecycle. This study, which combined laboratory experimentation and studio practices, aimed at production of glass glaze with cathode ray tube screen. Cathode ray tubes of four different colours were used for the study. The tubes were washed, pulverized and sieved according to their colour, elementally analysed using Particle Induce X-ray Emission, and milled into two batches per colour with first batch mixed with ball clay and second batch mixed with ball clay and additive chemical material of borax. The glaze batches were applied on eight bisque-fired tiles and fired at 1100 0C. The glazes yielded greenish grey, greyish purple, transparent grey and dark grey. This is significance towards the diversification of Nigeria’s economy for solving solid waste disposal challenges for a better and safe environment. The study has proven that cathode ray tubes with addition of borax and ball clay are suitable for glaze production and provided elemental information to guide the glaze formulation.

USE OF CATHODE RAY TUBE (CRT) COMPOSITE WASTE GLASS FOR NUCLEAR SHIELD TILES

This research is aimed at producing radiation shield tiles from cathode ray tube waste glass, borosilicate waste glassand soda lime silicate waste glass. The waste glasses were sourced for and crushed to powder. The powder wassieved through a 0.25 mm sieved with mesh number 60 and analysed using XRF spectrometer to ascertain theirchemical constituents. Twenty-one samples were generated using a 21-point triaxial blend of the three wasteglasses. The various samples were poured into moulds, fired in an electric furnace at 1000oC and soaked for anhour. Radiation shielding test using a radioactive source (cobalt 60) was carried out. The radiation shielding testsshows that sample 1 which comprises of 100% CRT had the highest radiation shielding ability with 0.178 cm-1linear attenuation coefficient and sample 21 which is made up of 100% soda lime silicate glass had the leastradiation shielding ability with 0.109 cm-1 linear attenuation coefficient.According to the 49th NCRP report,conventional tiles HVL for 60-Co gamma is 6.2 cm; whereas HVL for the RST in this work ranges between 3.8-6.3cm which shows that the RST is within the range of offering a good radiation protection. The results obtained in thisstudy showed that the radiation shielding tiles developed can be used as wall tiles in nuclear power facilities andmedical X-ray systems.

Recycled cathode ray tube waste glasses for radiation shielding applications: Role of Na2CO3

The aim of the study is to evaluate the ability of cathode-ray tube funnel waste glasses (CRT-F) to shield photons (gamma and X-ray) and other forms of radiation with rest masses (i.e., neutrons and charged particles) after their Pb content was reclaimed. The lead (Pb) content of cathode-ray tube funnel waste glasses (CRT-F) was reduced using Na2CO3 as the reducing agent CRT-F(Na2CO3). CRT-F and CRT-F(Na2CO3) were produced using the melt and quench processes using the powder of pristine funnel glass from discarded cathode ray tube glass and the reduced glass powder, respectively, as the starting materials. The X-ray fluorescence technique was adopted for determining the chemical composition of CRT-F and CRT-F(Na2CO3) glasses. The parameters relating to the gamma photon, fissile neutron, moderated neutron, slow neutron, and charged radiation (β, H+, He2+, and C6+) attenuation abilities of pristine CRT-F and CRT-F(Na2CO3) were evaluated. The FLUKA simulation code and XCOM were used to estimate the mass attenuation coefficient of the glasses. The stopping power (Sp) and range (R) of β, H+, and He2+ were evaluated by using the NIST data-based calculators (ESTAR for β, PSTAR for H+, and ASTAR for He2+) while Sp and R data for C6+ was determined using SRIM. The cross section for fast, thermal (25 meV), and slow neutrons (0.1–10 meV) was also estimated. The Pb reclamation from the CRT-F drastically increased the half value layer of photons by at least a factor of 4 at 0.1 MeV and by more than 90 % at 10 MeV. The CRT-F interacts more with fissile and thermal neutrons compared to CRT-F(Na2CO3). Although, CRT-F showed a better ability to attenuate all the radiation types considered, both glasses are better absorbers of radiation (especially photons) than some common shields. The reduction of Pb weight in CRT-F resulted in a drastic reduction in the ability of the glass to attenuate radiation; the resulting glass (CRT-F(Na2CO3)) is however, an environmentally safer glass shield.

An alternative classification approach for waste electronic and electrical equipment (WEEE) recovery in low-income countries: case study in Burkina Faso.

Waste electrical and electronic equipment (WEEE) is defined as "urban mines" due to the various recoverable minerals they contain. However, current WEEE classification methods are mostly limited to their physical characteristics, focusing on collection, transport, and treatment purposes rather than on valorization. In the present study, our aim is to propose an alternative classification approach adapted for low-income countries for WEEE recovery that highlights their content of precious and valuable metals. A typology of WEEE was created based on WEEE generated in Ouagadougou (Burkina Faso). Principal component analysis (PCA) and the moving center technique (K-means) were used for the classification method. Ultimately, we have found that to improve the recovery of WEEE, they can be classified into three main groups: (i) a group of WEEE-containing batteries, (ii) a group of WEEE-containing valuable and precious metals, and finally, (iii) a group of WEEE made up of cathode ray tube televisions (CRT-TV) waste. The WEEE belonging to the second group are the ones that could generate higher economical values. This alternative classification approach will help investors and operators to better orient their valorization activities towards WEEE types that present the best precious metals recovery potential, maximizing their profits. On the other hand, decision-makers will find this classification useful for reorganizing the WEEE value chain.

СТРУКТУРА ПОР ЯЧЕИСТОГО БЕТОНА С ОТХОДАМИ СТЕКЛОБОЯ ЭЛЕКТРОННО-ЛУЧЕВЫХ ТРУБОК

To date, the issue of handling toxic unsorted waste of cathode ray tubes (CRT) glass cullet remains relevant. The present paper proposes to replace part of the fine aggregate of cellular concrete intended for sound, heat or radiation protection with CRT glass waste heat-treated in the presence of a sodium hydroxide solution. The purpose of the research is to study the structure formation of the cellular concrete pores in case of replacement of part of the aggregate. The microscopy of the samples fracture was studied both visually and using software that made it possible to estimate the pore size when convert-ing the image to the relief mode. The study showed that the aggregate replacement results not only in quantitative changes in pore size, but also in qualitative changes related to the mechanism of the pore structure formation. Thus, when adding unsorted waste heat-treated in an alkaline environment, with a particle diameter of no more than 630 μm, there was a decrease in pore size and a decrease in size distribution compared with the reference sample. The changes are caused by structure formation, which can be divided into two stages - the formation of conglomerates and their swelling. With a decrease in the diameter of the part of the waste of a maximum size of 90 μm, a decrease in the pore size was recorded compared to the reference value, but due to the concrete skeleton formation before the end of gas development, destruction of the pore walls was observed.

Electromagnetic scattering and imaging simulation of extremely large-scale sea-ship scene based on GPU parallel technology

Aiming to solve the bottleneck problem of electromagnetic scattering simulation in the scenes of extremely large-scale seas and ships, a high-frequency method by using graphics processing unit (GPU) parallel acceleration technique is proposed. For the implementation of different electromagnetic methods of physical optics (PO), shooting and bouncing ray (SBR) and physical theory of diffraction (PTD), a parallel computing scheme based on the central processing unit (CPU)-GPU parallel computing scheme is realized to balance computing tasks. Finally, a multi-GPU framework is further proposed to solve the computational difficulty caused by the massive number of ray tubes in the ray tracing process. By using the established simulation platform, signals of ships at different seas are simulated and their images are achieved as well. It is shown that the higher sea states degrade the averaged peak signal-to-noise ratio (PSNR) of radar image.

Cathode Ray Tube Glass as an Aggregate: A Step Towards Greener Concrete

The use of Cathode Ray Tube (CRT) glass as an aggregate in concrete is a promising approach for sustainable construction. The CRT technology, once innovative, is now obsolete, leading to the accumulation of millions of CR tubes globally, posing disposal challenges due to their toxic composition. The CRT glass, consisting mainly of silica along with various oxides and heavy metals, holds potential for recycling and reuse applications. Recycling methods for CRT glass, including closed-loop and open-loop recycling, offer avenues to mitigate waste and conserve resources. Integrating CRT glass into concrete improves mechanical properties and durability. Although replacing natural sand with CRT glass may slightly reduce compressive strength, innovative mix designs offset this effect. Concrete with CRT glass exhibits resistance to environmental factors, making it suitable for diverse construction applications. Addressing environmental concerns related to CRT glass disposal requires efficient recycling technologies and stringent regulations. Overall, integrating CRT glass into concrete presents a sustainable solution to mitigate environmental impacts while enhancing concrete performance.

Development of an Integrated Process Flowsheet to Recover Valuable Metals from Waste Cathode Ray Tubes and Printed Circuit Boards

Electrical and electronic waste is considered a valuable stream of secondary metal resources because it contains metals such as copper, silver and gold. However, it is also classified as hazardous waste as it contains toxic heavy metals such as lead and cadmium. If electronic waste is not managed properly, the toxic metals may pose serious risks to the environment and human health, especially complex fractions such as printed circuit boards (PCBs) and cathode ray tubes (CRTs). The current study investigated a new process for the thermal treatment of CRTs and PCBs in an integrated flowsheet for metal recovery. Smelting tests were conducted to demonstrate that oxidative smelting of PCB concentrate and recycled CRT slag can produce a crude copper alloy with a grade of more than 95%. Another set of smelting tests was conducted to demonstrate that reductive smelting of CRT funnel glass and recycled PCB fume can produce a crude lead alloy with a grade of more than 95%. The investigations were undertaken in a pilot-scale top blown rotary converter (TBRC). The PCBs were smelted under mildly oxidising conditions at temperatures up to 1350 °C. The CRTs were smelted under mildly reducing conditions at temperatures up to 1250 °C. The study demonstrated that it is technically feasible to produce crude alloys of copper and lead from electronic waste, using an integrated process flowsheet.Graphical

Effect of Using Recycled Colemanite Waste and Cathode Ray Tube Glass in the Cement Mortar on Physical and Mechanical Properties

In this study, the performance of colemanite, which is a valuable boron waste, and recycled cathode ray tube glass (CRT) in the cement mortar was examined by experimentally. Colemanite waste (CW) and CRT were replaced with cement and aggregate and used as mineral additives, and their effect on the physical and mechanical properties (PP and MP) of mortar was investigated. In addition to the reference sample that didn’t contain CW or CRT, seven more samples were used. In these samples, cement was used at a rate of 2.5% along with CW, and the aggregate was replaced with CRT at the rates of 10%, 20%, and 30%, and with the combination of CW and CRT. The workability, unit weight, and water absorption, compressive strength (CS), flexural strength (FS), and abrasion resistance properties of the mortars were compared. As a result of this study, it has been observed that the use of waste materials can make positive contributions to some of the PP and MP of the mortar. Thus, the goal of both improving the properties of the mortar and making it affordable by using waste materials were achieved.

Recycling of Yttrium and Europium from Microwave-Roasted Waste Cathode Ray Tube Phosphor Powder

Recycling of Yttrium and Europium from Microwave-Roasted Waste Cathode Ray Tube Phosphor Powder

Functionalization of mesoporous Al-MCM-41 for indoor humidity control as building humidity conditioning material

This study sought to overcome the high energy consumption of mechanical dehumidifiers by synthesizing humidity control materials using alumino-silicate raw materials extracted from stone sludge and cathode ray tube (CRT) waste panel glass. The structure of the synthesized materials matches that of Mobil Composition of Matter No. 41 (MCM-41) mesoporous molecular sieves, which was subjected to amine functionalization using (3-Aminopropyl) triethoxysilane at various concentrations (2.5, 5, 7.5 vol.%). The resulting materials were characterized using X-ray fluorescence analysis, small angle X-ray diffractometry, Fourier transform infrared spectroscopy, transmission electron microscopy, the Brunauer–Emmett–Teller method, and 27Al solid-state nuclear magnetic resonance spectrometry. Al-MCM-41 molecular sieves with 5.0% grafted amine functional groups presented high specific surface area and high pore uniformity resulting in the highest equilibrium moisture content (39.4 kg/kg). The high thermal and humidity buffer capacity of the proposed material could greatly enhance the comfort of interior spaces without the energy consumption of mechanical dehumidifiers.