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A study was conducted to investigate how the addition of WO3 affects the mechanical, optical, and photon attenuation properties of TeO2–Na2O glass systems. In this study, four glass systems categorized as W5, W10, W15, and W20 were studied to evaluate the impact of WO3 on TeO2–Na2O glass systems in view of the feature of mechanical, optical, and photon attenuation. The rising values of elastic moduli suggest that increasing WO3 on TeO2–Na2O glass systems makes the glassy structure more stable. Incorporating WO3 into TeO2–Na2O glass systems results in an increased energy band gap, rising from 2.83 to 2.95 eV. This phenomenon, in turn, leads to a decrease in the refractive index, dielectric constant, and optical dielectric constant values from 2.444 to 2.411, 5.975 to 5.811, and 4.975 to 4.811, respectively. While the linear attenuation coefficient (LAC) of the examined glass systems (W5, W10, W15, and W20) displayed a comparable pattern, the LAC value of glass sample W20 stood out as the highest among them. However, due to the addition of WO3 on the TeO2–Na2O glass system, at a lower energy region from 0.0284 to 0.06 MeV, there was a little variation among the mass attenuation coefficients of these glass systems studied herein, but a negligible variation was found from 0.662 to 2.51 MeV. The studied glass sample W20 with the highest amount of WO3 (20 mol%) on the TeO2–Na2O glass system displayed the lowest half-value layer. However, glass samples W5, W10, and W15 exposed 1.29, 1.07, and 1.03 times higher values of mean free path than W20. In addition, the values of the half-value layer were compared with the literature data of WO3–MoO3–TeO2, BaO–Li2O–B2O3, and CaF2–BaO–P2O5 glass systems. Studied glass sample W20 showed the maximum shielding performance from energy 0.284 to 2.51 MeV.

In various medical, industrial, and nuclear facilities, it is very necessary to have enough shielding against the radiation released by regularly employed isotopes. In this work, we concentrate on nuclear security as well as the radiation shielding against gamma attenuation capabilities of the borate glasses, including Te and Cu. These glasses have the chemical form of (100-x)[30B2O3–70TeO2]-xCuO, where x = 0, 0.005, 0.01, 0.015, 0.02 wt%. The systems were represented by five distinct samples, labelled as BTCu-20, BTCu-15, BTCu-10, BTCu-5, and BTCu-0, where the number refers to the percentage of CuO in the mixture and the remainder is made up of TeO2 and B2O3. Through the use of FLUKA simulations, the basic characteristics associated with gamma shieldings, such as attenuation and transmission factors, were examined for the particular energy range of 238–1408 MeV emitted from 133Ba, 137Cs, 60Co, 152Eu, and 232Th. The effect of the systematic replacement of CuO by B2O3 and TeO2 on the shielding qualities was explored in depth for gamma radiation. In addition, comparison research was carried out between the currently available borate glasses and the traditional shielding materials. According to the findings of the current investigation, the GHVL was found to be its lowest at 238 keV with values of 0.87, 0.92, 0.98, 1.04, and 1.10 (cm) for BTCu-0, BTCu-5, BTCu-10, BTCu-15, and BTCu-20 glasses, respectively. This points to the possibility that the BTCu-0 sample might be used in radiation shielding applications, which would result in increased nuclear safety.

A direct-doping method was tested to design new composite-glasses by incorporating lanthanum niobate nanocrystals (NC) in tellurite glasses. NC powder were grinding with glass powder before heating-quenching, with the main investigation approached of best parameters for NC suitable homogenization but limited dissolution. Thermal analysis signalizes that prior heat-treatment of NC promotes higher transparency and limits NC dissolution. These materials with visually detectable NC aggregates exhibited glass transition temperatures close to the starting glass. LaNbO4 phase was hardly detected by X-ray diffraction because of the low weight ratio and partial dissolution but the monoclinic polymorph could be identified for lower time. UV-visible-NIR transmission spectra also related progressive lower transparency with light scattering of NC aggregates. Photoluminescence suggest that lower times allowed to ensure the NC environment with lower crystallinity around Eu3+-ions in final composite-glass. These results pave the way for designing new materials containing NC not achievable by conventional nucleation-growth methods.

We investigated the radiation shielding competence for TeO2–V2O5–MoO3 glasses. The Phy-X software was used to report the radiation shielding parameters for the present glasses. With an increase in TeO2 and MoO3 content, the samples' linear attenuation coefficient improves. However, at low energies, this change is more apparent. At low energy, the present samples have an effective atomic number (Zeff) that is relatively high (in order of 16.17–24.48 at 0.347 MeV). In addition, the findings demonstrated that the density of the samples is a very critical factor in determining the half value layer (HVL). The minimal HVL for each sample can be found at 0.347 MeV and corresponds to 1.776, 1.519, 1.391, 1.210 and 1.167 cm for Te1 to Te5 respectively. However, the highest HVL of these glasses is recorded at 1.33 MeV, which corresponds to 3.773, 3.365, 3.218, 2.925 and 2.908 cm respectively. The tenth value layer results indicate that the thickness of the specimens needs to be increased in order to shield the photons that have a greater energy. Also, the TVL results demonstrated that the sample with the greatest TeO2 and MoO3 concentration has a higher capacity to attenuate photons.

Leishmaniasis is a group of diseases caused by infection with Leishmania parasites. The lesions that develop as a result of leishmaniasis can vary depending on the species of the parasite and the type of leishmaniasis. Cutaneous leishmaniasis is the most common form of the disease and it results in skin sores or ulcers. Materials with manganese oxide (Mn2O3) nanoparticles and tellurium oxide (TeO2) nanorods have been shown to have antibacterial, antifungal, and antiparasitic effects. The purpose of this study was to ascertain how Mn2O3 and TeO2 nanoparticles affected Leishmania major-caused wound healing in rats. The albino rats were separated into four groups of five once a lesion appeared on their tails. In the two treatment groups, Mn2O3 and TeO2 nanoparticles were injected every day, once a day, intra-wound in three places, and in the meglumine antimoniate group, the drug was injected intramuscularly for five weeks. The albino rats in the negative control group did not receive any medication. The size of the wounds in the group treated with Mn2O3 nanoparticles did not differ significantly from the control group that did not receive treatment, however the diameter of the wounds in the group treated with TeO2 nanorods did change significantly from the control group that did not receive treatment. It was, however, larger than the group that received meglumine antimoniate treatment. TeO2 nanorods, as opposed to Mn2O3 nanoparticles, had an in vivo anti-Leishmanial potential. [ABSTRACT FROM AUTHOR]

PMMA (Poly methyl methacrylate) composites have promising potential for applications in optics and dielectric energy storage. To investigate the effects of TeO 2 contents in PMMA in this respect, we studied their composites on light absorption in the UV visible range, structural analysis via X-ray diffraction, dielectric characteristics, and free volume behavior. We added up to approximately 7 % of the weight concentration of the TeO 2 micropowder to the PMMA matrix for effective dispersion because of the limitations of ultrasonic agitation. The XRD data demonstrate a widening of the peaks with a filler content of up to 4.8 % and agglomeration at 7 %, indicating TeO 2 particle contact. An increase in absorbance was observed in the UV visible spectrum of the PMMA/TeO 2 composites with increasing TeO 2 content up to 4.8 %. The dielectric constants exhibit a positive correlation with higher quantities of TeO 2 , and the polarization mechanism is interpreted by interface polarization and free volume. The free volume measured by positron annihilation lifetime spectroscopy (PALS) increases to 4.8 % but decreases to 7 %. The effect of the free volume within the matrix on the polarization distribution of TeO 2 influenced the dielectric constant and the loss factor, which increased to 4.8 % and then decreased to 7 % due to agglomeration. • Free volume behavior of PMMA/TeO 2 was investigated using the Positron Spectroscopy in both the glassy and molten phases. • The XRD spectrum reveals a broadened peak with TeO 2 content consistent with the free volume. • UV–visible absorbtion spectra aligns well with composite free volume. • Free volume quantity interpretes dielectric permitivity and loss factor using filler-matrix interface polarization. • PMMA/TeO 2 composites exhibit highly favorable dielectric characteristics, increasing the dielectric constant about 20 %. [ABSTRACT FROM AUTHOR]

In this research, polymers were fabricated through combining polyester, boron oxide (B2O3), and Tellurium oxide (TeO2). B2O3 has good neutron absorption and TeO2 is not only highly dense (5.670 g/cm3) but also environment-friendly, compared to PbO, as well as being a good photon absorber. The radiation protection features for five investigated samples were examined utilizing an HPGe detector and point sources Am-241, Cs-137, and Co-60. The accuracy of the experimental setup of this experiment was proven through the linear attenuation coefficient (LAC) values obtained from the theoretical (XCOM) and experimental (HPGe) values of the newly developed polymers. The attained results showed that the values of LAC decrease with increasing energy. Moreover, at low energy, a noteworthy increase was found for the LAC values with the addition of TeO2. Due to the increase in TeO2 content of the polymers, the value of the half value layer (HVL) decreases from 6.073–4.193 cm at energy 0.662 MeV, from 7.973–5.668 cm at energy 1.173 MeV, and 8.514–6.061 cm at energy 1.333 MeV. The values of the effective atomic number (Zeff) showed an improvement with the increase in TeO2 content in the polymers. For example, at energy 0.150 MeV, the Zeff values of the prepared sample followed this decreasing trend - PBT-40 > PBT-30 > PBT-20 > PBT-10 > PBT-0. [ABSTRACT FROM AUTHOR]

This paper has focused on the investigation of gamma and neutron attenuation properties of Li 2 O–B 2 O 3 –P 2 O 5 –TeO 2 glass system. Gamma shielding parameters such as mass attenuation coefficients ( μ m ), effective atomic numbers (Z eff), half value layers (HVL), tenth value layers (TVL), mean free path (MFP), effective electron density (Ne), equivalent atomic numbers (Z eq) of investigated glass samples have been calculated in a wide photon energy range of 0.02–20 MeV using MCNPX general purpose Monte Carlo code. The calculated results for mass attenuation coefficients were compared with XCOM. In addition, exposure buildup factors (EBF) and energy absorption buildup factors (EABF) of investigated glasses were determined by using the G-P fitting method. The results showed that sample 9 with the highest density had the lowest HVL, TVL and MFP values among the investigated glasses. Moreover, effective removal cross-sections (Σ R) and transmission factors (TFs) have been calculated. The obtained results have shown that the TeO 2 additive into glass samples had a positive effect on the nuclear protection performance of the investigated glass samples. It can be concluded that the impact of TeO 2 additive for nuclear radiation shielding applications can be further investigated in different types of glass systems. [ABSTRACT FROM AUTHOR]

Abstract The objective of the study was the structural analysis of the 70TeO2-5XO-10P2O5-10ZnO-5PbF2 (X = Mg, Bi2, Ti) tellurite glasses doped with ions of the rare-earth elements Er3+, based on the PALS (positron annihilation lifetime spectroscopy) method of measuring positron lifetimes. Values of positron lifetimes and the corresponding intensities may be connected with the sizes and number of structural defects, the sizes of which range from a few angstroms to a few dozen nanometers. Experimental positron lifetime spectrum revealed existence of two positron lifetime components τ 1 andτ 2. Their interpretation was based on two-state positron trapping model where the physical parameters are the positron annihilation rate and positron trapping rate.

Cordierite 2MgO+2Al2O3+5SiO2 is frequently used ceramic material, that is commonly used as a carrier of electrical components due to its low dielectric constant (~ 5), and low temperature thermal expansion coefficient (20·10-7 oC-1). In order to accelerate the process of sintering, 5.00 mass% TeO2 was added to the starting mixtures. System was tested in two parallel mixtures, one with no additives, and the other one with TeO2. The mechanical activation of the both mixtures was performed in a highenergy ball mill in time intervals from 0 to 40 min with ball to powder mass ratio 1:40. The particle size analysis (PSA) was employed in order to determine the changes in the particle size of the mechanically treated powders. The phase composition of the starting powders as well as microstructures was analyzed by the means of X-ray diffraction method and SEM.

In this paper, the tellurite glasses76.4TeO2-12Nb2O5- 12.6ZnO doped with 3000ppm Tm2O3 ions were prepared by conventional melt quenching method. The optical properties of the glasses were estimated by measuring UV.Vis-NIR spectroscopy in the range from 200 to 2500 nm and linear refractive indices (n) at different wavelength was estimated. From the absorption edge studies, the value of optical band gap (Eopt) was determined. Moreover, the nonlinear refractive index (n2), third-order nonlinear susceptibility (Ô(3)), and nonlinear absorption coefficient, (β), were observed. It is noticed that (n2), Ô(3) and β increase by decreasing the value of optical band gap (Eopt). The classical McCumber theory was used to evaluate the emission cross-sections for the 3F4 3H6 transition at a wavelength of around 2µm. Gain cross-section for the Tm3+ laser transition 3F4? 3H6 was obtained. These glasses have the effective emission cross section bandwidth (108 nm) and large stimulated emission cross-section (28.37?~10-21cm2). Spectroscopic properties indicate that these glasses doped with Tm3+ are a promising candidate for optical applications and may be suitable for optical fibre lasers and amplifiers. Furthermore, the structures of these glasses were analyzed by Raman Ramanspectroscopy. [ABSTRACT FROM AUTHOR]

The crystal structure of γ-TeO2 was redetermined on the basis of single-crystal X-ray diffraction data. The previous structure determination of this modification was based on laboratory powder X-ray diffraction data [Champarnaud-Mesjard et al. (2000). J. Phys. Chem. Solids, 61, 1499–1507]. The current redetermination revealed all atoms with anisotropic displacement parameters, accompanied with a much higher accuracy and precision in terms of bond lengths and angles, and the determination of the absolute structure. The crystal structure consists of TeO4 bisphenoids that combine through corner-sharing of all their oxygen atoms into a three-dimensional framework.

This work intends to analyse the microstructure of paratellurite (TeO2 single crystals) plastically deformed at high temperature (∼870 K) in uniaxial compression along [110]. Samples have been mechanically tested, and thin foils have been cut from them, corresponding to the slip systems to be observed in transmission electron microscopy. The study of the dislocation substructure in this material is rather complex due to its high anisotropy. Microstructural observation by TEM has put into evidence the presence of dislocation dissociation. This is the first work reporting this fact. From the equilibrium distance between partials, an estimation of the stacking fault energy has been carried out.En este trabajo se pretende analizar la microestructura de monocristales de TeO2 (paratelurita) deformados plásticamente en compresión uniaxial a alta temperatura (∼870 K) en distintas condiciones. Para ello, se han ensayado muestras con orientación cristalográfica [110], y se han cortado láminas correspondientes a los planos de deslizamiento para ser observadas con microscopía electrónica de transmisión. El estudio de la subestructura de dislocaciones en este material es complejo debido a su alta anisotropía. La observación de dicha microestructura ha puesto de manifiesto la presencia de disociación de dislocaciones. Es la primera vez que se encuentra este fenómeno en la paratelurita. De la distancia de equilibrio entre dislocaciones parciales, se ha podido obtener una estimación de la energía de falta de apilamiento en este sistema.

A system based on the xLi2O-(1-x)[30V2O5-70TeO2] glassy system have been prepared by classical melt-quenching technique and their thermal and electrical properties were studied in the range from x = 0 up to 0.4. It has been observed on these glasses that with increase of Li2O concentration Tg decreases as well conductivity, however when x reaches 0.2-0.3 values conductivity begin to increase (Tg behavior remains unaltered). Results have been discussed on the basis of network modification that would occur in the glass base structure by the addition of Li2O. Those glasses show high promise as potential mixedionic materials.El sistema vítreo xLi2O-(1-x)[30V2O5-70TeO2] ha sido preparado por la técnica tradicional de enfriamiento rápido (“melt quench”) y sus propiedades térmicas y eléctricas han sido estudiadas en el rango de x = 0 a 0.4. En este sistema se ha observado que la transición vítrea y la conductividad disminuyen a medida que aumenta la concentración de Li2O pero, por otro lado, cuando x = 0.2-0.3 la conductividad comienza a aumentar (la transición vítrea continua disminuyendo). Los resultados obtenidos se han discutido en términos de modificación de la estructura vítrea base en relación a la adición de Li2O y en términos de basicidad óptica. Estos vidrios muestras propiedades prometedores como materiales de conductividad mixta.

A facile one-step synthesis of CdTe quantum dots (QDs) in aqueous solution by atmospheric microwave reactor has been developed using 3-mercaptopropionic acid reduction of TeO2 directly. The obtained CdTe QDs were characterized by ultraviolet-visible spectroscopy, fluorescent spectroscopy, X-ray powder diffraction, multifunctional imaging electron spectrometer (XPS), and high-resolution transmission electron microscopy. Green- to red-emitting CdTe QDs with a maximum photoluminescence quantum yield of 56.68% were obtained. [ABSTRACT FROM AUTHOR]

We have developed a number of programmable hyperspectral imagers operating from the ultraviolet to the longwave infrared using an acousto-optic tunable filter (AOTF) in conjunction with a suitable camera. Each of these AOTFs is fabricated with a single transducer to operate over only one octave in wavelength. Recently, we have developed two separate tellurium dioxide (TeO2) noncollinear AOTF cells that operate over two octave range. Each cell has an aperture of 1.5 × 1.5 cm2 with a field-of-view of 4.2°, and two thin-plate lithium niobate transducers are bonded on it. The tuning range of the first cell is 0.43–2.1 μm, and 0.69–4.0 μm for the second cell. We have used each of these cells to carry out spectral imaging experiments with CCD, InGaAs, and InSb cameras to cover the spectral region from the visible to the midwave infrared. We image the two orthogonally polarized diffracted beams to get spectropolarimetric information from the scene, as well as a broadband image by using one of the undiffracted beams. In this paper, we discuss the two AOTF cells, the imaging experiments, and present the results obtained. [ABSTRACT FROM AUTHOR]

The radiation shielding characteristics of samples from two TeO2 and Sb2O3-based basic glass groups were investigated in this research. TeO2 and Sb2O3-based glasses were determined in the research as six samples with a composition of 10WO3-(x)MoO3-(90 − x)(TeO2/Sb2O3) (x = 10, 20, 30). A general purpose MCNPX Monte Carlo code and Phy-X/PSD platform were used to estimate the radiation shielding characteristics. Accordingly, the linear and mass attenuation coefficients, half value layer, mean free path, variation of the effective atomic number with photon energy, exposure and built-up energy factors, and effective removal cross-section values were determined. It was determined that the results that were produced using the two different techniques were consistent. Based on the collected data, the most remarkable findings were found to be associated with the sample classified as T80 (10WO3 + 10MoO3 + 80TeO2). The current study showed that material density was as equally important as composition in modifying radiation shielding characteristics. With the T80 sample with the greatest density (5.61 g/cm3) achieving the best results. Additionally, the acquired findings were compared to the radiation shielding characteristics of various glass and concrete materials. Increasing the quantity of MoO3 additive, a known heavy metal oxide, in these TeO2 and Sb2O3-based glasses may have a detrimental impact on the change in radiation shielding characteristics. [ABSTRACT FROM AUTHOR]

In the present study, a novel process for effective recoveries of Te and Cu from copper telluride from anode slime processing in copper smelters was proposed. The process consists of two hydrometallurgical steps of atmospheric alkaline leaching for Cu and Te separation, and TeO 2 precipitation with H 2 SO 4 for Te recovery. The effects of NaOH concentration, liquid to solid ratio, temperature, H 2 O 2 to Cu 2 Te mole ratio, and reaction time on the dissolution behavior of tellurium were investigated. A Te leaching efficiency of about 91% was obtained under the optimal experimental conditions. The results of thermodynamic and kinetic analysis indicate that a lower temperature is favorable for the dissolution of Te, and mass transfer inside the solid particle is the rate-determining step. In addition, a mechanochemical-assisted leaching was conducted, by which Te leaching efficiency was enhanced to approximately 93% with ball milling at 180 rpm for 5 h. After Te leaching, H 2 SO 4 was utilized to adjust the pH value of the Te-containing alkaline leach solution to 4.5 for TeO 2 precipitation. The crystallization of TeO 2 can be completed by reacting for 1 h and the overall tellurium recovery has reached nearly 90%. Image 1 • One-step separation of Cu and Te was achieved by atmospheric alkaline leaching. • Thermodynamic and kinetic analysis of Te dissolution process were conducted. • Ball milling treatment was employed to enhance Te selective dissolution process. • An overall Te recovery of 90% was achieved by precipitating TeO 2 from solution. • A complete and efficient technology for copper telluride recycling was proposed. [ABSTRACT FROM AUTHOR]

Copper telluride is a sort of solid waste generated from copper anode slime processing, from which the recovery of copper and particularly the high-value element of tellurium always encounter technical difficulties due to the complex physicochemical properties of tellurium. In this study, an efficient and compact process for copper telluride recycling has been developed. Efficient separation of tellurium and copper from copper telluride was achieved through a pressure oxidizing alkaline leaching process under the optimal conditions of 5 mol/L for NaOH concentration, 5:1 for liquid to solid ratio, 150 °C for temperature, 0.7 Mpa for system pressure, and 2 h for reaction time, by which over 95% of tellurium was selectively dissolved in the solution and copper was enriched in the solid phase mainly in the form of copper oxides. Tellurium was subsequently recovered as TeO 2 by neutralization of the alkaline leaching solution with sulfuric acid to pH 4.5, delivering a TeO 2 precipitation efficiency of over 95%. In general, the masses of tellurium and copper balanced well in both the liquid and solid phases for each step, and the overall recovery efficiencies of Te and Cu reached as high as approximately 91% and 98%, respectively. Unlabelled Image • Atmospheric and pressure oxidizing alkaline leaching processes were compared. • One-step separation of Cu and Te was achieved by pressure alkaline leaching. • Thermodynamic and kinetic analysis of Te dissolution process were conducted. • Overall recovery efficiency of 91% and 98% for Te and Cu respectively were reached. • A complete and efficient technology for copper telluride recycling was proposed. [ABSTRACT FROM AUTHOR]