Lead Monoxide Research Articles

Enhancing mechanical and radiation shielding properties of concrete with lead monoxide and granodiorite: Individual and synergistic effects at micro and nano particle scales

AbstractThis study investigates the individual and combined effects of micro and nano lead monoxide (PbO) and granodiorite (GD) on concrete's mechanical and radiation shielding properties. Both materials were partially substituted for cement at varying ratios. Additionally, mixtures with optimal radiation shielding performance were prepared to explore the synergy of combining them. The mentioned materials are used for the first time in an extensive study at the nano scale to investigate their impact on concrete's mechanical properties, microstructure, and gamma radiation attenuation. Two gamma ray sources of uranium (U238) and cesium (Cs137) were used measure the radiation attenuation coefficients for all designed concrete mixes. A simple methodology was followed to assess the concrete shields efficiency via utilizing portable handheld gamma‐ray spectrometer that offers two reading modes. Results indicated that increasing the ratio of PbO is directly proportional to the concrete ability to attenuate radiation, where the optimal individual replacement ratios were recorded at 5% for micro and nano particle sizes. At this ratio, the linear attenuation coefficient (μ) values were improved by 39.57% and 24.78% for the nano and micro PbO, respectively. Additionally, the optimal ratio for improving mechanical properties was at 3% and 2% for nano and micro PbO, while the higher ratios showed a decline in mechanical properties especially at 5% micro PbO with 7.02% reduction in the compressive strength value. Regarding GD powder, the optimal replacement ratios for improving concrete radiation shielding were consistent with those enhancing its mechanical properties at 4% and 7% in both nano and micro scales, respectively. The combined mixes further enhanced the overall concrete performance, especially its radiation shielding ability. Compared to the control mix, the compressive strength, tensile strength, and μ were increased by 25.7%, 16.2%, and 44.7% at the optimal mixture of 5% nano PbO + 4% nano GD.

The mechanism of Fleury test for morphine

The test under study is due to M. Fleury. He used morphine dissolved, at room temperature, in 1/20 N sulphuric acid; added some lead superoxide (lead dioxide), stirred for 8 min., let stand 4 min; the water-clear liquid was separated, and a drop of ammonia was added. A brown colour occurs immediately. These experimental data indicate not a fast reaction, but a rather complex mechanism. In this communication a reaction mechanism is provided for the first time. Protonated lead dioxide is the reactive species which on interaction with the phenol group in morphine forms a mixed ortho-plumbate. Protonation of this ester does not favor further reaction. However, reaction with a second reactive species is favourable for a push-pull seven-member reaction mechanism. Enolization of the dienone formed restores aromaticity. Protonation of the Pb=O double bond in the obtained intermediate promotes a 7-atom concerted mechanism. 2,3-Dioxomorphine is formed along with an oxide hydrate that yields water and two molecules of plumbous oxide.

Newly observed low-lying Ω = 1 state of PbO.

High-resolution spectroscopy of lead monoxide was performed in a range of 22 400-25 300 cm-1. A new Ω = 1 state located between the a1 and A0+ states was observed, and it is labeled c1. Spectroscopic constants, including the hyperfine interaction coefficient, were determined for the a1 and c1 states. The vibrational levels of these two electronic states are located closely to each other, and the interaction between them causes gradual exchange of electronic state properties in our observation wave number range. Our observation poses a question for the band assignment for the b0- state, which has some resemblance with this c1 state.

In Ukrainian

The results of theoretical modeling of the spatial structure and electronic absorption spectra of isolated small particles of polymorphic modifications of lead monoxide - litharge and massicot, which are characterized by the presence of hypercoordinated atoms, have been analyzed. The optical properties of many oligomers of lead oxide are systematically considered in the work. The results of quantum chemical calculations by the methods of electron density functional theory (DFT and TDDFT) on the spatial structure and energy characteristics, as well as the electronic absorption spectra of the considered models, are discussed. Theoretical results are compared with available experimental data. The calculation method used and the proposed cluster models with or without attached (chemisorbed) water molecules allow us to reproduce the spatial structure and energy characteristics of polymorphic modifications of lead oxide at a semi-quantitative level. It has been found that the addition of water molecules to models for α-lead oxide nanoparticles contributes to their stabilization. The calculated values of the cohesion energy for litharge nanoparticles are greater than those for massicot ones, which corresponds to the experimental data for lead monoxide crystals. The calculated electronic spectra of the litharge nanoparticle models are characterized by absorption bands which lie in the region that corresponds to the red color, and those of massicot relate to yellow; the corresponding values of the width of the energy gap for the litharge models are smaller than for the massicot ones, which is consistent with the experimental data for crystals. The results of calculations show that the presence of hydroxyl groups in nanoparticle models leads to a hypsochromic shift of absorption maxima, so that with a sufficient number of such groups, these species may lose their color.

A novel approach for the efficient recovery of lead from End-of-Life Silicon Photovoltaic modules

There is an urgent need to develop a technology for recycling solar waste that will soon be generated in heaps. While various studies focused on recovering valuable materials from waste silicon solar panels, there has been minimal emphasis on the treatment of toxic substance lead. Thus, the current study proposed a novel approach to treat the harmful component of lead by recovering it in its less toxic form as PbO having commercial applications. This is accomplished through optimization of a three-step process (i) selective leaching of the top layer from interconnect, (ii) extraction of lead from the leachate by precipitation, and (iii) calcination. The lead recovery at each stage was analyzed by characterization techniques viz. ICP-OES, XRD, SEM, and a unique attempt has been made to optimize the precipitation process by constructing an Eh vs. pH diagram. The efficient leaching of lead from interconnects was observed with 1.5 M nitric acid for 5 min at 60 °C which was followed by precipitation from the leachate with 1.5 M NaOH solution and finally calcination at 500 °C for 2 h to obtain lead monoxide. The feasibility of the optimized process at a larger scale was carried out with 200 g (60-cell panel) of copper ribbons.

Semiconducting Double-Layer Lead Monoxide Tin Oxide Nanostructures for Photodetectors

Semiconducting Double-Layer Lead Monoxide Tin Oxide Nanostructures for Photodetectors

Study of ethylene propylene diene monomer-lead monoxide-magnetite composites in radioactive waste disposal

In this study, ethylene propylene diene monomer (EPDM)-lead monoxide (PbO)-magnetite (Fe3O4) composite was prepared and changes in its properties with different gamma irradiation doses (50, 100, 200, 300, 500, and 1000 kGy) were investigated. Characterizations of irradiated EPDM-metal oxide composites were performed by X-ray Diffractometer (XRD), Field Emission Scanning Electron Microscope (FESEM) and Universal Testing Machine (UTM). It was observed that the synthesized sample shows an amorphous nature beyond the 500 kGy irradiation dose. The FESEM morphographs of irradiated samples show an increase in fracture size with an increase in irradiation dose. The mechanical tests have shown that prepared samples retain their mechanical strength up to ∼100 kGy. In addition, the effect of thermal and electrical properties on irradiation dose has also been studied. The synthesized samples show good thermal stability up to ∼500 kGy. The AC conductivity of the synthesized EPDM-metal oxide composites has been observed to increase slightly with an increase in irradiation dose. It was observed that synthesized EPDM-metal oxide composites are relatively good radiation resistant candidates and can be used for radioactive waste disposal management applications.

External Bremsstrahlung Studies on Films of Lead Monoxide Filled Polycarbonate Composite

The development of high-Z (high atomic number) radiation shielding materials is vital in order to protect personnel who work with harmful gamma radiation sources. At the same time, the emission of external bremsstrahlung (EB) radiation in those shielding materials when the radiation source emits beta particles as well as gamma radiation is also of prime concern.The production of EB in films of lead monoxide (PbO) loaded polycarbonate (PC) composite at eleven different filler levels (FLs) varying, in terms of weight fraction, from 0.0 % up to 10.0 % were investigated experimentally by using beta particles from strontium-90/yttrium-90 (90Sr/90Y) radioactive source. A nonlinear relation is observed between EB intensity and target thickness. The effective atomic numbers of the prepared PbO-filled PC composite films (at different FLs) were determined via EB measurements, followed by calculations, and the values obtained were compared with the modified atomic numbers which were determined for the same composite films (at different FLs) using the Markowicz and Van Grieken equation, and it was found that they are in good agreement. Finally, the atomic number dependence of EB in these composite films (PbO-filled PC composites) has been studied. It is obtained that the intensity of EB spectra depends on the square of the atomic number of the target material.

Lead Monoxide Nanostructures for Nanophotonics: A Review

Black-phosphorus-analog lead monoxide (PbO), as a new emerging 2D material, has rapidly gained popularity in recent years due to its unique optical and electronic properties. Recently, both theoretical prediction and experimental confirmation have revealed that PbO exhibits excellent semiconductor properties, including a tunable bandgap, high carrier mobility, and excellent photoresponse performance, which is undoubtedly of great interest to explore its practical application in a variety of fields, especially in nanophotonics. In this minireview, we firstly summarize the synthesis of PbO nanostructures with different dimensionalities, then highlight the recent progress in the optoelectronics/photonics applications based on PbO nanostructures, and present some personal insights on the current challenges and future opportunities in this research area. It is anticipated that this minireview can pave the way to fundamental research on functional black-phosphorus-analog PbO-nanostructure-based devices to meet the growing demands for next-generation systems.

A novel design of mechanical metamaterial incorporating multiple negative indexes

Mechanical metamaterials that combine multiple negative properties are rare, but have great appeal for applications in multipurpose devices. Herein, a novel metamaterial incorporating negative Poisson’s ratio, negative compressibility, and negative thermal expansion or swelling was proposed. The unit cell was designed by simulating the bond structure of lead monoxide crystals using elastic beams. Analytical models for the mechanical responses of the unit cell were established, and expressions for Young’s modulus, thermal expansion, Poisson’s ratio, and compressibility were derived and confirmed by numerical simulations. The results showed that the metamaterial not only displayed a negative Poisson’s ratio but also had negative linear and area compressibilities as well as negative linear, area, and volume thermal expansions if the geometric parameters were properly adjusted. Furthermore, metamaterials with negative linearity and area swelling were obtained experimentally by replacing the thermal expansion of the material with the water absorption expansion of a hydrogel. Such metamaterials with multiple negative indexes are expected to contribute to the feasibility of advanced multifunctional devices with mechanical, pressure, temperature, and moisture sensitivities.

Radiation shielding properties of the doped carbon fiber-reinforced epoxy composites

In this study, the linear attenuation coefficients of the doped carbon fiber-reinforced epoxy composites (Boron Oxide (B2O3), Lead Monoxide (PbO) and Zinc Borate (2ZnO 3B2O3 3H2O)) for the gamma radiation are investigated with the help of the High Purity Germanium (HPGe) Detector. The doped carbon fiber-reinforced epoxy composites were prepared with different proportions of additive materials (10, 20, and 30 wt%) so that impact of the additive amount on radiation shielding could be properly analysed. The specimens were tested at 7 different energy levels ranging from 82.0 to 1332.0 keV with the use of HPGe detector. Further on, the effect of additive materials on mechanical properties was also examined. Findings indicate that all additives into composite materials improve the gamma attenuation ability, and the best gamma shielding characteristic is obtained in the case of 30 wt% Lead Monoxide sample. On the other hand, 10 wt% additive materials provide increase in stiffness compared with undoped samples.

Lead Recovery From PbO Using Hydrogen as a Reducing Agent

A systematic isothermal reduction study was carried out on pure PbO pellets using 15 pct H2/85 pct N2 gas. The reduction was carried out at 350 °C to 800 °C at different reaction times (30 minutes to 4 hours) with gas flowrate of 500 mL/min. The kinetics of the reaction were evaluated by measuring the mass change and applying kinetic models to the data. The results from microstructure observation showed that globular and non-wetting lead droplets form on the surface of PbO samples. The droplet's diameter was observed to increase with increasing temperature and reduction time. It was observed that this lead droplets layer, once covers the whole surface, appears to reduce the overall reduction rate. The kinetics analysis showed that PbO pellet reduction is a diffusion-controlled process as supported by the SEM (scanning electron microscope) micrographs, samples’ cross-section observation, and phase analyses using EDS (energy-dispersive spectrometry) and XRD (X-ray diffraction). The energy activation, Ea, was calculated for two temperature ranges, i.e., 61 kJ/mol (for 350 °C to 450 °C) and 224 kJ/mol (for 600 °C to 800 °C), respectively. These results suggest that, in an industrial context, continued reduction process will require constant removal of lead product from the surface of the lead monoxide.

High-resolution spectroscopy of the X [formula omitted] A[formula omitted], C[formula omitted] transitions of PbO in 22 300–25 100 cm-1

High-resolution excitation spectra of the X0+→ A0+ and X0+→ C0+ transitions of lead monoxide (PbO) are observed in a range of 22 300-25 100 cm−1. Transition frequencies are determined with an average uncertainty of 8.5×10−4 cm−1 by comparing with resonances of an ultralow expansion etalon. PbO molecules are produced by laser ablation in a cold helium buffer gas, which provides rotationally cold but vibrationally hot molecules and allows observation of hot bands of excitation from the υ′′=1,2 vibrational states. Spectroscopic constants and potential curves for the A0+ and C0+ states are determined, and the spectroscopic constants obtained for the three main isotopologues are reproduced to a satisfactory level using a single potential curve for each electronic state. This indicates that perturbation due to other electronic states is negligibly small.

EFFICACY OF Nigella sativa OIL TO RELIEVE EFFECTS OF THE LEAD MONOXIDE TOXICITY ON TESTICULAR EFFICIENCY AND SEXUAL BEHAVIOUR DISORDERS IN ALBINO RATS

The prevalence of testicular toxicity induced via contamination with heavy metals is increasing worldwide, and a close connection between testicular toxicity and lead has recently been identified. The present study demonstrated the possible therapeutic and protection properties of Nigella sativa oil (NSO) against dangerous testicular toxicity and sexual behaviour disorders in rat models induced by lead monoxide (PbO) food poisoning. A total of 24 male rats were used and divided into four groups, consisting of Group 1: Control (1 mL of distilled water); Group 2: PbO (80 mg/kg); Group 3: NSO (0.5 mL/rat); and Group 4: (NSO+PbO) 0.5 mL/rat of NSO, followed by PbO (80 mg/kg/day) respectively for 60 days. The testosterone, follicle-stimulating hormone (FSH), luteinizing hormone (LH), 17 beta-hydroxysteroid dehydrogenase activity (17β-HSD), sperm parameters, and sexual behaviour (copulation behaviour test) were measured. The results showed that sex hormone levels were significantly decreased (p<0.05) in rats exposed to PbO, while the levels of these hormones were significantly higher in rats exposed to NSO and NSO+PbO. The sperm parameters (numbers, concentrations, motilities, and abnormality) were lower in rats exposed to PbO compared to those in the control, NSO, and NSO+PbO groups that showed significant increases. Sperm abnormality and 17β-HSD activity showed a significant increase at p<0.05 in the group exposed to the PbO compared to those of the control, NSO, and NSO+PbO groups. The results also significantly suppressed sexual behaviour in rats exposed to PbO compared to those in the control, NSO, and NSO+PbO groups, rats were administered NSO+PbO showed improvement in sexual behaviour parameters compared to PbO groups. PbO toxicity was obvious in the reproductive tract through severe histopathological changes. The impact of lead on tissues was partially mitigated by NSO. The study showed protective effects of N. sativa oil against changes in sex hormones, sperm characteristics, and sexual behaviour in male rats exposed to lead monoxide-induced testicular toxicity.

Reactive Oxygen Species Sequestration Induced Synthesis of β-PbO and Its Polymorphic Transformation to α-PbO at Atomically Thin Regimes.

The emergence of attractive properties in materials at atomically thin regimes has seen an ongoing interest in two-dimensional (2D) materials. An aspect that has lacked focused attention is the effect of 2D material thickness on its crystal structure. As several layered materials naturally exist in mixed metastable phases, it raises an important question of whether a specific polymorph of these mixed-phase materials will be favored at atomically thin limits. This work attempts to address this issue by employing lead monoxide as a model 2D polymorphic system. We propose a reactive oxygen species (ROS) sequestration-mediated liquid-phase exfoliation (LPE) strategy for the facile synthesis of ultrathin PbO. This is followed by a suite of microscopic and spectroscopic analyses of the PbO nanosheets that reveals the polymorphic transformation of orthorhombic (β) PbO to its tetragonal (α) analogue with reduction in nanosheet thickness. The transformation process reveals an interesting crystal structure of ultrathin 2D PbO where [001]-oriented domains of α-PbO coexist alongside [100]-oriented regions of β-PbO. Density functional theory (DFT) calculations support our experimental data by revealing a higher thermodynamic stability of the tetragonal phase in PbO monolayers. These findings are likely to instigate interest in carefully evaluating the crystal structures of ultrathin 2D materials while promoting research in understanding the phase transformation across a range of 2D crystals.

Potential Impact of Smog on Human Health

Smog is a term used to describe pollution suspended in humid air. It's made up of different- sized dust particles, as well as non-metal oxides, organic compounds, and heavy metals. Apart from smoking cigarettes, one of the changeable variables leading to the development of respiratory diseases is exposure to toxic compounds dispersed in the air. . Smog is a visible form of air pollution that arises due to the over-emissions of some primary pollutants like volatile organic compounds (VOCs), hydrocarbons, SO, NO, and NO2 which further react in the atmosphere and give rise to toxic and carcinogenic secondary smog components. There are six categories of airborne chemicals that have a negative impact on public health and cause disease. Ozone, particulate matter (PM) of various dimensions - PM2.5, PM2.5–10, PM10, nitrogen – all has important implications. Lead, carbon dioxide, Sulphur dioxide, and carbon monoxide Small dust particles (PM10 and PM2.5) are given special attention since they can enter the lower respiratory tract. The page examines the impact of atmospheric pollutants on both the development and exacerbation of the disease, in addition to detailing the composition of smog and sources of air pollution. Asthma, chronic obstructive pulmonary disease, respiratory infections, and other respiratory tract illnesses can all cause symptoms. Lung cancer is a type of cancer that affects. Some of the legislative methods used in various nations to reduce exposure to harmful air pollution are presented.

Chemical speciation of lead adsorbed onto volcanic ashes by ICP-OES and XANES

This study focuses on the assessment of the VA materials from the Cameroon volcanic line (CVL) for their use as natural adsorbents to remove Pb(II) pollutant from aqueous solutions. The chemical speciation of lead adsorbed onto volcanic ashes based by means of inductively coupled plasma optical emission spectroscopy (ICP-OES) and X-ray absorption near edge spectroscopy (XANES) study is reported. The ashes from CVL are used to remove lead in aqueous solutions. The maximum value of the adsorption capacity of lead in volcanic ashes was 7.60 mg g-1 at pH 5. Regarding the adsorption process, the contribution of the mixture lead components after adsorption and a strong interaction of adsorbed lead with the surface of volcanic ashes were proven. The chemical elements present in the volcanic ash and their concentrations are determined by ICP-OES. Chemical speciation was carried out measuring Pb saturated volcanic ash sample at the L3 edge (13035 eV) at the XAFS beam line in Elettra Sincrotrone Trieste. The XANES measurements showed that the lead removal occurred mainly by microprecipitation of lead acetate and carbonate associated with a possible ion-exchange forming lead monoxide.

Performance evaluation of lead-monoxide dosimeter with parylene coating for quality assurance of brachytherapy devices

The source position of irradiation is identified using a method that uses rulers and films for quality assurance (QA) in brachytherapy. However, this method involves a high probability of errors, because the scales are checked using the naked eye, and QA is indirectly performed using photographs. Lead monoxide (PbO) is widely used as a semiconductor dosimeter, because it is a photoconductor that generates electrons in response to electromagnetic waves. Moreover, PbO has excellent sensitivity to reflected rays, owing to its high atomic number (Z Pb: 82, Z O: 8) and density (ρPbO: 9.53 g/cm3). We applied PbO to a dosimeter for QA in a brachytherapy device and attempted to increase the signal stability with a parylene coating for performance improvement. Subsequently, a comparative analysis was performed with a PbO dosimeter that was not coated with parylene to determine whether the fabricated dosimeter is applicable as a dosimeter for QA of the brachytherapy device, by analyzing the reproducibility, linearity, percentage interval distance (PID), and angular dependence in the 192Ir source used for brachytherapy. The RSD of the non-parylene PbO dosimeter was 0.85%, and the RSD of the parylene PbO dosimeter was 0.40% in the reproducibility results. In the linearity evaluation results, the R 2 value of the non-parylene PbO dosimeter was 0.9996, and that of the parylene PbO dosimeter was 0.9997 In the PID evaluation results, the difference in the intensity distribution measured according to the distance due to the dose was attenuated at the coated parylene in the case of the parylene PbO dosimeter. Therefore, adjustments using correction coefficients are required for suitable performance. In the angular dependence evaluation results, the parylene PbO dosimeter had 3.44% less angular dependence than the non-parylene dosimeter at an angle of 45°. The parylene-coated PbO dosimeter showed better performance than the non-parylene-coated PbO dosimeter in terms of the reproducibility, linearity, and angular dependence. Therefore, it is considered that the parylene-coated PbO dosimeter can be implemented for QA of brachytherapy devices.

Experimental investigations on the beta attenuation properties of lead monoxide – Polycarbonate composite films

Lead monoxide filled polycarbonate polymer composite films have been prepared with twelve different filler levels, ranging from 0.5 up to 10.0 percent by weight, by using ultrasonic dispersion of lead monoxide in the polycarbonate solution, followed by solution casting. For these composites, beta radiation shielding properties such as mass attenuation coefficient, range of beta particles and half value layer thickness for beta particles from low activity thallium −204 and yttrium – 90 radioactive sources have been found experimentally and computationally, along with the mass density and modified atomic number of the composite material. Two different computational methods, namely, Baltakment’s empirical formula method and Bragg’s mixture rule have been used to calculate the theoretical value of mass attenuation coefficient, whereas Katz and Penfold relationship has been used to calculate the range of the beta particles obtained from these sources in the prepared composite films. The results obtained are discussed.

Comparative Physicochemical Analysis of Kushta-E-Murdarsang Prepared by Classical and Muffle Furness Method

<p style="text-align: justify;"><strong>Aim:</strong> <em>Kushta-e-Murdarsang </em>a herbo-mineral calx preparation was prepared as per classical and contemporary method and its physico-chemical and elemental analysis for standardization and safety evaluation (by heavy metal estimation) was performed. <strong>Methods:</strong> <em>Murdarsang </em>(Litharge mineral) was subjected to Mudabbar / Shodhan (processing) by Sheere- Madar (Latex of <em>Calotropis gigantea </em>Linn. R. Br. ex. Ait.) and calcined by classical and muffle furness method. Comparative Physico-chemical investigation for safety evaluation and standardization were done by X-ray diffraction (XRD), inductively coupled plasma mass spectrometry (ICP-MS), Atomic absorption spectroscopy (AAS) and other analytical parameters. <strong>Results:</strong> Both the sample <em>Kushta-e-Murdarsang</em> classical method (KM-CM) and <em>Kushta-e-Murdarsang </em>Muffle Furnace method (KM-MFM) passed specification tests as per Unani Medicine. Both the sample KM-CM and KM-MFM showed presence of heavy metals. In XRD analysis both the samples showed presence of Lead, sample KM-MFM revealed presence of Litharge syn- PbO phase, where KM-CM revealed presence of Lead syn- Pb, Galena syn- Pb S and Litharge syn- PbO phase. In ICP-MS analysis the Cadmium (Cd) content was 0.65 ppm and 0.65 ppm; Mercury (Hg) 54.17 ppm and 68.08 ppm and Arsenic (As) was 21.27 ppm and 0.11 ppm accordingly, in AAS analysis the Lead (Pb) content was 55.0 % and 51.4% in KM-MFM and KM-CM respectively. <strong>Conclusion: </strong>KM-MFM can be a better choice in respect of only ease of preparation, both the sample prepared by classical along with muffle furnace method contains heavy metal above permissible limit and KM-CM contain reduced quantity of heavy metal in respect of MF method. XRD and other standardization data for the formulation were set in. <p style="text-align: justify;"><strong>Key words:</strong><em> Murdarsang,</em> Lead monoxide, Litharge, Unani Medicine, Kushta, Safety.