Archimedes Method Research Articles

Decomposition Pathways of EC and Effects of Additives: Accounting for Liquid, Gas, and Solid Phase Reactions during the First Charge

The majority of lithium-ion batteries (LIBs) utilize carbonate-based electrolytes, due to the good lithium solvation, electrochemical stability, and electrode passivation.1 Studies regarding decomposition pathways and other reaction mechanisms2-4 of carbonates in LIBs are abundant in the literature but few attempt to quantify total losses of these solvents. Quantitative measurement of solvent loss from the electrolyte would significantly inform the comprehensive picture of electrolyte reaction mechanisms in the cell. Furthermore, this approach allows for the study of any effects additives may have on carbonate solvent decomposition. For example, organosilicon (OS) additives have been shown to reduce gassing and improve high temperature cycling in carbonate-based LIBs,5 but their quantitative impact on EC decomposition is not known.In this poster, we detail our methodology for quantitatively tracking and characterizing different forms of ethylene carbonate (EC) decomposition in a LIB pouch cell as well as the effects of organosilicon additives on these reactions. This study focused on the loss of EC after the first charge when the majority of SEI formation occurs. Liquid phase composition, including both EC and its decomposition products, was quantified by NMR analysis (1H and 19F) of extracted electrolyte using internal standards (LiPF6 and 1,4-bis(trifluoromethyl)benzene). Gas phase decomposition was characterized by a combination of the Archimedes method (to quantify gas volume) and GC-MS analysis (to determine gas composition). Finally, the impact of OS additives on the decomposition pathways of EC was examined. Inclusion of OS molecules reduces EC decomposition during the first charge, predominately by reducing the amount of liquid phase decomposition. 1Xu, K. Chem. Rev. 2004, 104, 4303-4417. 2 Campion, C.; Li, W.; Lucht, B. Thermal Decomposition of LiPF6-Based Electrolytes for Lithium-Ion Batteries. Journal of the Electrochemical Society 2005, 152, A2327. 3 Seo, D.; Chalasani, D.; Parimalam, B.; Kadam, R.; Nie, M.; Lucht, B. Reduction Reactions of Carbonate Solvents for Lithium Ion Batteries. EC Electrochemistry Letters 2014, 3, A91-A93. 4 Xing, L.; Li, W.; Wang, C.; Gu, F.; Xu, M.; Tan, C.; Yi, J. Theoretical Investigation on Oxidative Stability of Solvents and Oxidative Decomposition Mechanism of Ethylene Carbonate for Lithium Ion Battery Use. J. Phys. Chem. 2009, 113, 16596-16602. 5 Guillot, S.L.; Usrey, M.L.; Peña-Hueso, A.; Kerber, B.M.; Zhou, L.; Du, P.; Johnson, T. Reduced Gassing in Lithium-Ion Batteries with Organosilicon Additives. J. Electrochem. Soc. 2021, 168, 030533-030543.

The effect of microwave energy on sintering of an austenitic stainless steel reinforced with boron carbide

Microwave heating has emerged as an alternative to traditional sintering methods because it consumes less energy and requires shorter processing times. The use of microwave energy in the processing of austenitic stainless steel AISI 316L reinforced with dispersed boron carbide particles was investigated in this study. Different processing parameters were used to investigate the effect of sintering time and temperature, as well as the weight percentage of the ceramic added to the steel matrix, on the final material properties. The compressibility curve, elastic relaxation, and geometric density of green compacts were used to investigate their physical properties. The Archimedes method was used to determine density, and the statistical treatment of analysis of variance was used to determine porosity. Images obtained using optical microscopy and scanning electron microscopy revealed the formation of a second phase in different volumes. The results showed that 1100 °C and a 15-minute plateau were sufficient to sinter the material. AISI 316L samples containing 3 wt.% boron carbide demonstrated greater volumetric formation of secondary phases, resulting in a significant increase in the hardness of the austenitic composite developed.

Methodological analysis of composites Green Polyurethane Resin reinforced with jute fabric

Currently, the scientific community is focusing to develop news materials that shall be environmentally friendly; this mindset is growing and leading to a huge increase in new papers on that effort. The main idea in our research field is to discover new eco-friendly composites that can replace some synthetic originated or non-renewable sources. For this, the castor oil based polyurethane matrix represents an ecologically correct option for the use of polymeric matrices. Moreover, the use of natural fibers instead of synthetic ones makes an even greener composite. This research sought to analyze vegetable polyurethane resin from castor oil as matrix reinforced by jute fabric. The fabric apparent density was determined by Archimedes method, obtaining a value of 2.4 g/cm3. Subsequently, samples of the composite were made in open silicone rubber mold for the charpy impact test and compared with specimens made in a closed metallic mold under pressure. The composites received 0–6 layers of jute fabric. As a result, the better impact resistance was with open mold reached a notch resistance of 226.34 J/m for 2-layer composites. In addition, the values of 3–6 layers in open mold were significantly better than those of closed molds, varying from 20 % up to 174 % better. The pressing step in a closed mold is not necessary; consequently, we saved money and time to manufacture this type of composites, for these purposes.

Effect of sintering parameters on the microstructure and micromechanical properties of in-situ synthesized boride phases (Fe2B-FeB) in iron matrix composites reinforced with B4C particles

In this study, the influence of sintering parameters on the microstructure and micromechanical properties of ceramic reinforced iron matrix composites is investigated. Composites containing 5–10-20-30 vol% B 4 C were fabricated by in-situ powder metallurgy (IPM) and sintered at various temperatures and durations. Hot pressed powder mixtures were sintered at constant duration (60 min at 1000–1150-1300 °C) and constant temperature (1150 °C for 30–120 min) in a protective environment. The influence of these parameters is evaluated by investigating microstructural changes using SEM, XRD, EDX, and optical microscopy, density and porosity by Archimedes method, and finally, micromechanical properties by hardness determination. Results showed that while increasing reinforcement ratios of B 4 C particles caused reduced density in the green compacts, B 4 C particles under a certain size (<7 μm) were randomly distributed in the mixture and lead to the formation of iron borides. Additionally, increased hardness was witnessed for all temperatures with increasing reinforcement ratios until 20 vol% B 4 C, after which hardness was decreased. In fact, 20 vol% B 4 C showed excellent properties and was comparatively much sensitive to both, increasing sintering temperatures and duration. In-situ synthesized iron borides became the decisive factor in the increased hardness of the composites. • The properties of Fe-B 4 C composites were evaluated at various sintering parameters. • The iron boride phase was formed in different sizes and shapes as a result of the diffusion of boron from the B 4 C. • Composition of mixture powders and sintering time affected the dispersion of the boride phase. • The hardness of composites was significantly developed by in-situ synthesized boride phases. • Sintering time causes the phase formation in larger areas that enhanced the overall hardness.

Effect of exfoliated MoS2 on the Microstructure, Hardness, and Tribological Properties of Copper Matrix Nanocomposite Fabricated via the Hot Pressing Method

In this study, copper matrix composites were prepared using the cold and hot pressing technique and then investigated to select the suitable one for the self-lubricating applications. A hybrid of alumina and molybdenum disulfide with a 1:1 ratio by the mechanical milling for 40 h was proceeded to peel the molybdenum disulfide and cover the alumina particles with their layers. Three different samples like Cu, Cu/10 Al2O3, and Cu/hybrid 20(Al2O3–MoS2) were mixed for 15 h. The ball-to-powder ratio in the two mentioned steps was 10:1. The X-ray analysis, HRTEM, Raman spectra, and scanning electron miscopy were used to study the crystal structure, chemical composition, and morphology of the new hybrid and prepared samples. The density was evaluated by the Archimedes method. Mechanical properties, including hardness, wear rate, and coefficient of friction, were investigated. The mixing for 15 h improves the exfoliation of MoS2 flakes inside the copper matrix. A clear hardness improvement was achieved by adding alumina and the mixture of (Al2O3–MoS2). The copper sample reinforced with the hybrid of alumina/MoS2 gave the lowest mechanical wear rate and the lowest average friction coefficient of 0.17.

Validation of Archimedes Method and Acid Dissolution Test for Volume Fraction Determination of Aluminum Alloy Composites Reinforced with Ceramic Particles

Metal matrix composites are the novel engineering materials finding applications in several extreme environmental and industrial requirements leading to the developments of numerous types of its kind in recent decades. Powder metallurgical techniques is one among the promising methods of producing intricate shaped end products out of the MMCs. Essentially the uniformity in distribution of the reinforcements and the accuracy in employing the percentile addition of the reinforcements decide the tailor made properties of these composites. There are several techniques to evaluate the reinforcement percentage and uniformity. This work concentrates on the analysis of effectiveness of volume fraction determination methods namely Archimedes test and acid dissolution test for 7075 Al/Al2O3 composite. Using the two methods the volume fraction of 7075Al/ Al2O3 composite prepared by powder metallurgy technique is determined. Advantages and disadvantages of both methods were analyzed using the result analysis and the observation indicated that the acid dissolution test produces more accurate results than the Archimedes test. In addition, the randomized selection of the specimens out of the end products leads to the corroboration of reinforcement uniformity in the composite matrix.

Analysis of element loss, densification, and defects in laser-based powder-bed fusion of magnesium alloy WE43

It is well known that laser-based powder-bed fusion (L-PBF) additive manufacturing of magnesium (Mg) and its alloys is associated with high Mg loss due to vaporization (Mg Loss ) and high incidence of many types of defects in the manufactured parts/samples. Despite this, Mg Loss , densification, and defect characteristics have not been holistically considered in the determination of the optimal values of L-PBF processing parameters for Mg and its alloys. This study presents a combined modeling and experimental approach applied for a widely used Mg alloy (WE43) to address this shortcoming in the literature. First, an experimentally calibrated model is proposed to determine Mg Loss as a function of the L-PBF processing parameters. The model couples the temperature profile using a double ellipsoidal heat source with a Langmuir vaporization model and is calibrated using the width of the single-track L-PBF process and the measured Mg loss using inductively coupled plasma mass spectrometry (ICP-MS). Second, the densification of the samples is determined using a modification of the Archimedes method that considers the amount of Mg Loss in the calculation of the relative density. Third, a comprehensive and quantitative study is conducted on the relationships between the characteristics of porosity defects and the L-PBF processing parameters. Finally, the optimized L-PBF processing parameters are determined by considering the Mg Loss , densification, and the characteristics of defects. The present study yields 0.23 wt.% Mg Loss compared to 2 wt.% Mg Loss that was reported in the previous studies. Furthermore, more than 99.5% densification is achieved while only ∼2% and ∼0.5% of the total defects are characterized as keyhole and lack of fusion defects, respectively.

Surface Characteristics and Flexural Strength of Porous-Surface Designed Zirconia Manufactured via Stereolithography.

To design and fabricate zirconia bars with porous surfaces using stereolithography and evaluate their surface characteristics and flexural strengths. Five groups of zirconia bars (20 mm × 4 mm × 2 mm) with interconnected porous surfaces were designed and manufactured: (i) 400-µm pore size and 50% porosity (D400-P50 group), (ii) 400-µm pore size and 30% porosity (D400-P30 group), (iii) 200-µm pore size and 50% porosity (D200-P50 group), (iv) 200-µm pore size and 30% porosity (D200-P30 group), and (v) 100-µm pore size and 30% porosity (D100-P30 group). Zirconia bars without a porous surface (NP) were used as controls. The surface topographies and pore structures were investigated using scanning electron microscopy and three-dimensional laser microscopy. The printed porosity was calculated using the Archimedes method. Fifteen specimens from each group were subjected to a three-point bending test according to the ISO 6872:2015 standard. A Weibull analysis was performed, and the fractured surfaces were examined using scanning electron microscopy. Zirconia bars with porous surfaceswere designed and successfully manufactured. The designed pore size, porosity, and shape of the printed pores were approximately achieved for all the porous surfaces. The flexural strength of the control group was significantly higher than those of the groups with porous surfaces (p < 0.001). For the same porosity, groups with a pore size of 400 µm exhibited a lower flexural strength than the other groups (p<0.001). Additionally, for the same pore-size design, the flexural strengths of group D400-P50 and D400-P30 exhibited no significant differences (p = 0.150), while the flexural strengths of D200-P30 were significantly higher than that of the D200-P50 group (p = 0.043). The control group and D400-P50 group had higher Weibull moduli than the other groups. The fractography of the specimens with porous surfaces indicated more than one crack origin, mainly owing to defects, including pores and cracks. Zirconia bars with porous surfaces were successfully designed and fabricated using the stereolithography technique. Although porous surfaces may be advantageous for osteogenesis, the porous-surface design can reduce the flexural strength of the printed zirconia bars. By reducing the pore size, controlling the porosity, and improving the printing accuracy, a higher strength can be achieved.

Combined and alone addition effect of nano carbon black and SiC on the densification and fracture toughness of SPS-sintered ZrB2

ZrB2-nano-size carbon black (C.Bn), ZrB2-SiC, and ZrB2-SiC-C.Bn specimens were fabricated by spark plasma sintering (SPS) at 1850 °C for 8 min under 35 MPa pressure. The bulk density (B.D) was measured by the Archimedes method. The single-edge notched beam (SENB) method was applied to investigate the fracture toughness and work of fracture (WOF). It was found that the combined addition of C.Bn and SiC modified the densification behavior to reach full-densified samples. Also, it was found that the fracture toughness and WOF were improved by the addition of C.Bn to the monolithic ZrB2 continuously, and they reached 5.1 ± 0.1 MPa·m1/2 and 433 ± 20 J·m−2, respectively for the sample containing 15 vol% C.Bn. Compared to monolithic ZrB2, the fracture toughness and the WOF for the composite with 30 vol% SiC and 15 vol% C.Bn increased nearly 26 % and 57 %, respectively. It was noteworthy that the alone addition of C.Bn to the pure ZrB2 had more effect in improving the fracture toughness than the simultaneous addition of C.Bn and 30 vol% SiC. The predominant mechanisms in fracture toughness improvement can be related to the observed crack deflections, branching, and bridging in scanning electron microscopy (SEM) images.

Mullite Reinforced SiC/Al2O3 Composites Prepared by Microwave Sintering Based on Green Manufacturing

In the preparation process of composites, the implementation of green manufacturing technology has an important impact on improving material properties and preparation efficiency. The adopting of green manufacturing technology not only greatly reduces the energy consumption but also effectively avoids the environmental pollution. Compared with the traditional material preparation process, the material preparation process for green manufacturing is a new concept and idea. Microwave sintering is such an efficient, clean, and pollution-free preparation process, so it is widely used in the field of material preparation. By microwave sintering, the mullite reinforced SiC/Al2O3 composites with different SiC particle size were prepared from the composite powders composed of SiC particles coated with SiO2, by a sol-gel method and Al2O3 particles. The effect of SiC particle size on the microstructure, bulk density, fracture toughness, flexural strength, and thermal shock resistance of SiC/Al2O3 composites was studied. The bulk density, fracture toughness, and flexural strength were evaluated by the Archimedes method, single-side notched beam method, and three-point bending method, respectively. The thermal shock resistance of samples was investigated through the combination of water quenching and three-point bending methods. The results showed that with the increase of SiC particle size, the bulk density, fracture toughness, and flexural strength of samples all increased first and then decreased. The bulk density, fracture toughness, flexural strength, and flexural strength retention of SiC(5 μm)/Al2O3 composites were better than those of other samples, which were 2.06 g/cm3, 1.98 MPa·m1/2, 63 MPa, and 60%, respectively. The better mechanical properties and thermal shock resistance of SiC(5 μm)/Al2O3 composites are due to the formation of bridging mullite whiskers between SiC and Al2O3 particles with large length diameter ratio. Therefore, the unique sintering mechanisms of size coupling effect and local thermal aggregation effect in microwave sintering were discussed. The research results can not only provide reference for the preparation process of mullite reinforced SiC/Al2O3 composites but also for the wide application of microwave sintering technology.

Evaluations of frost and scaling resistance of fly ash concrete in terms of changes in water absorption and pore structure under the accelerated carbonation conditions

In this study, the frost and scaling resistance of concrete with various fly ash (FA) replacement ratios exposure to air and accelerated carbonation conditions were investigated. The changes in water absorption were measured by RILEM / CIF test and in pore structure were measured by the Archimedes method and the mercury intrusion porosimetry method due to carbonation. Results show that the influence of FA and carbonation on the frost and scaling resistance of concrete can be ignored due to air bubbles by air entraining (AE) admixture in case of AE FA concrete. For Non-AE FA concrete, carbonation of FA concrete does not change the gel porosity/capillary porosity ratio, which is the reason for the frost resistance is not influenced by carbonation of FA concrete. Additionally, it is noteworthy to note that the scaling resistance is strongly connected to the pore volume above 75 nm, and that when exposed to carbonation, the scaling resistance tends to rise as a result of the increase in pore volume above 75 nm that occurs as a result of carbonation. Because of the addition of FA and carbonation, the frost and scaling resistance are far more reliant on the changes in pore structure than they are on the water absorption.

Enlightening the structural, elastic, and luminescence properties of transparent Zn2SiO4 glass-ceramic by precipitation of Gd2O3 as dopant

This work focus on fabrication of new Gd3+-doped willemite (Zn2SiO4) glass-ceramics derived from the Gd2O3–ZnO–Al2O3–B2O3–SiO2 (Gd-ZABS) glass system by a controlled sintering process. The physical characteristic with formation of Gd3+-doped Zn2SiO4 glass-ceramic crystal phase, morphology and structural changes were examined by Archimedes method, X-ray diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM) and Fourier-transform infrared (FTIR) reflection spectroscopy. The appearance of SiO2, ZnO4 and Zn–O–Si bands indicate that the formation of Zn2SiO4 crystal phase. As for elastic analysis, the ultrasonic velocity and elastic coefficients showed an increasing tendency with the increase in sintering temperature. The study on energy transfer has found that the optical band gap of Gd3+-doped Zn2SiO4 glass-ceramic has decreased as the sintering temperature increased. The luminescence spectra of Gd3+-doped Zn2SiO4 exhibit several strong emission peak located at 425, 447, 462, 485 and 530 nm after the samples were subjected to 310 nm excitation source. Prominent green emission of Gd3+-doped Zn2SiO4 glass-ceramic were strongly observed at 530 nm. These spectra show that when the sintering temperature increases, the luminescence performance of the glass-ceramics has improved.

Effect of alumina insertion on structural properties, thermal stability, and chemical durability of potassium calcium based-phosphate glasses

The synthesis of six aluminum potassium calcium based-phosphate glasses with molar composition of xAl2O3-(50-x)P2O5-10CaO-40K2O, where × = 2.5, 5, 7.5, 10, 12.5, and 15 mol% was complemented. Their structural analyses were performed through XRD, SEM-EDX, DSC, FTIR, and Raman. Further density (ρ) estimations of all samples by the Archimedes method were carried out, and their chemical properties were examined in deionized water, HCl, and NaOH solutions at room temperature. The addition of Al2O3 to the system helped rising the density values (ρ), the glass transition temperature (Tg), and the crystallization temperature (Tx) while reducing the molar volume (Vm). The FTIR and Raman outcomes showed that the addition of alumina into the glass system affects the P - O - P bonds generating novel P-O-Al bonds, which compacts the glassy structure. The glasses’ weight loss studies displayed a decreasing tendency while increasing the content of Al2O3, leading to an enhancement in terms of chemical properties.

A critical assessment of the Archimedes density method for thin-wall specimens in laser powder bed fusion: Measurement capability, process sensitivity and property correlation

The Archimedes method is a commonly used approach for measuring the density of specimens fabricated with metal additive manufacturing. Most of the specimens fabricated for this purpose are cubes with 10 mm sides. This work examines the appropriateness of using the Archimedes method for estimating the density of thin-wall specimens (0.3–2 mm thick). The significantly higher surface area to volume ratio of these specimens, as well as their cumbersome size, can introduce measurement challenges not seen for the standard cubic specimens. The method is assessed for thin-walls in three ways: first, a Measurement Capability Analysis is conducted, quantifying repeatability and reproducibility and comparing them to those obtained for cubic specimens. Then, densities are assessed for their sensitivity for detecting differences due to changes in thickness, post-processing conditions (Hot Isostatic Pressing, or HIP) and build location. Finally, density values are correlated to mechanical tensile test metrics to establish trends and R2 values. The Archimedes method is shown to be capable of measuring thin wall densities for specimens as thin as 0.3 mm, though standard deviation is shown to increase as thickness reduces. The method is also sensitive enough to detect differences due to thickness and HIP, and to a lesser extent, build location. Finally, densities obtained from this method yield interesting insights for modulus, ultimate tensile strength and elongation, with R2 values in some cases exceeding 0.6. This work focuses on Inconel 718 tensile test specimens fabricated using the laser powder bed fusion process and demonstrates that the Archimedes method is a capable and critical tool in developing thin wall structures.

CHARACTERIZATION OF (Mg0.5ZN0.5)TiO3 CERAMICS AS MATERIAL CANDIDATES FOR DIELECTRIC RESONATOR AT MICROWAVE FREQUENCY

MgTiO3 ceramic is one of the dielectric materials used as a signal generator (dielectric resonator) in microwave telecommunication devices. This research is intended to explore the possibility of a new composition of MgTiO3-based ceramic, i.e. (Mg0.5Zn0.5)TiO3 (abbreviated MZT05) as a dielectric resonator material. The aim was to characterize the resonant frequency of the ceramics on the microwaves (measured using spectrum analyzer), and the results were correlated to structure (X-Ray Diffraction, XRD), microstructure (Scanning Electron Microscope, SEM), and bulk density data (Archimedes method) of the ceramics. The work was begun by compacting the MZT05 crystalline powder in a cylindrical shape with a diameter of 5 mm using a uniaxial die press to produce tablets. The tablets were sintered at 1300 ºC with variations holding times of 6, 8, and 10 h to produce ceramics. The structural data revealed that the MgTiO3 phase was identified as the main ceramics, i.e. (96.32-98.70) %molar. The bulk density increased with increasing sinter holding time, from 2.75 g/cm3 (6 h), 2.84 g/cm3 (8 h) to 2.99 g/cm3 (10 h) due to the increase in grain size diameter from 919.75 nm (6 h), 1090.62 nm (8 h) to 1180.72 nm (10 h) accompanied by a decrease in the size of the pore diameter from 924.14 nm (6 h), 917.05 nm (8 h) to 800.22 nm (10 h). The ceramics produced resonant frequencies of 5.07–5.08 GHz, which implies that the ceramics are proven to be potential candidates for dielectric resonator materials at microwave frequencies, especially at 5.07-5.08 GHz. The varying sinter holding time seems not to influence the resonant frequency of the ceramics because the variation holding times produce similar resonant frequencies.

Examining the Length and Density Changes of Copper up to 300 °C under the Influence of Consciousness Bond Field: A Study of Taheri Consciousness Theory

According to Taheri's theory of Consciousness, T-Consciousness can be converted into matter and energy and vice versa. Consciousness Bond Field is one of many Taheri Consciousness Fields (TCFs) founded and introduced by Mohammad Ali Taheri as new Fields. These Fields are neither matter nor energy; therefore, they do not possess a quantity, but they have direct effects on both matter and energy. In other words, although TCFs cannot be directly measured, we can investigate their effects indirectly through reproducible experiments. In this study, pure copper was selected to study its density and thermal behavior in the presence of the Consciousness Bond Field. Two meters of wire were cut from a cable and divided into two equal parts. Diffusion spectrometry was performed on the samples, and 15 pieces of 19.5 ±0.25 mm were cut from each sample. The density of the samples was examined by the Archimedes method. The samples were then heated up to 300 °C. The relative increase in their lengths was examined at targeted temperatures, and the density of the samples was measured once more. Radiographic examination was performed on the 12 samples. The test results showed that all parts were healthy and free of defects. The changes in density followed a pattern opposite to those of the control samples and inconsistent with the known laws of material physics. Considering the increase in length, the density should have been decreased significantly compared to the control samples following dilatometry, but this was not the case. The density of the samples under the Consciousness Bond Field increased despite the increase gained in length. As the samples were undamaged and intact, the sample mass must have increased according to the concept of density and its increase. An XRD sample from each group was investigated. The observed changes gave the possibility of higher defects in the sample under TCF.

Kinetics and mechanisms for the densification and grain growth of the α-alumina fibers isothermally sintered at elevated temperatures

Understanding the densification and grain growth processes is essential for preparing dense alumina fibers with nanograins. In this study, the alumina fibers were prepared via isothermal sintering at 1200, 1300, 1400, and 1500 °C for 1–30 min. The phase, microstructure, and density of the sintered fibers were investigated using XRD, SEM, and Archimedes methods. It was found that the phase transformation during the isothermal sintering enhances the densification of Al2O3 fibers in the initial stage, while the pores generated during the phase transformation retard the densification in the later period. The kinetics and mechanisms for the densification and grain growth of the fibers were discussed based on the sintering and grain growth models. It was revealed that the densification process of the fibers sintered at 1500 °C is dominated by the lattice diffusion mechanism, while the samples sintered at 1200–1400 °C are dominated by the grain boundary diffusion mechanism. The grain growth of the Al2O3 fibers sintered at 1200–1300 °C is governed by surface-diffusion-controlled pore drag, and that sintered at 1400 °C is dominated by lattice-diffusion-controlled pore drag.

John Wallis and the “Rectification” of the Parabola

The problem of the rectification of curves and the calculation (for which we shall adopt the more geometric term “flattening”) of the surface of a rotating solid generated by a curve, once the rotation axis has been fixed, were treated by John Wallis in two short inter-related tracts on cycloids and cissoids in 1659. In this work, we focus on the problem of the rectification of the parabola, an ancient problem reproposed in the 17th century, and on the solution obtained by Wallis using particular series that reflect the mechanical method of Archimedes, even if this is not immediately apparent to the reader. In presenting Wallis’s speech, we use the language closest to us and make explicit all the calculations not performed by the author, favoring an understanding of the part of his writing dedicated to the rectification of the parabola.

Assessment of mechanical and radiation shielding capacity for a ternary CdO–BaO–B2O3 glass system: A comprehensive experimental, Monte Carlo simulation, and theoretical studies

A Glass system consisting of ternary BaO, B2O3, and CdO compounds was fabricated using the melt-quenching method. The fabricated glasses density was measured using the Archimedes method and reduced in the range between 3.148 and 2.955 g/cm3, raising the CdO concentration in the glass network. The elastic moduli and some mechanical properties were calculated for the fabricated glasses based on the Makishima-Mackenzie model. The obtained results showed a diminished in Young, bulk, shear, longitudinal moduli, and the microhardness of the fabricated glass with the replacement of the BaO by CdO compounds. Moreover, the linear attenuation coefficient of the fabricated samples was measured via NaI detector at energies 0.662, 1.173, and 1.332 MeV emitted by the radioactive sources Cs-137and Co-60. The experimental data was confirmed using the XCOM program and Monte Carlo simulation. The highest linear attenuation coefficient is obtained for the fabricated glass without CdO content. It is decreased from 74.49 to 0.086 cm−1 between 0.015 and 15 MeV. Furthermore, the effect of partial replacement of BaO by CdO compounds on the effective removal cross-section for the fast neutrons was evaluated theoretically. Based on this factor, the fabricated glasses' relaxation length and half-value layer were also calculated.

Synthesis and structural characteristic of Nd3+/Er3+ co-doped Lithium Fluorophosphate (LFP) glasses

Transparent fluorophosphate glass containing face center cubic LiF crystals doped with Nd3+/Er3+ were succesfully characterized by melt-quenching method. The sample composition following chemical formula (65-x)P2O5-20LiF-14CaF-1Nd2O3-xEr2O3 (x = 0.0; 0.5; 1.0; 1.5 and 2.0 mol%). The density parameter was calculated using Archimedes method in distilled water and this value used to calculating of molar volume. Several physical properties of Nd3+/Er3+ co-doped LFP glasses were calculated and correlated with structural properties. The X-ray diffraction (XRD) spectrum used to verify the glasses structure. The further structural characteristic was investigated using FTIR. Based on the investigation is discovered that the prepared co-doped glasses shows amorf and high transparency.