Archimedes Method Research Articles

SLM Additive Manufacturing of Oscillating Heat Pipe

This study employed metal additive manufacturing technology to fabricate oscillating heat pipes using SUS316L as the material and conducted related printing parameter experiments and thermal performance tests. The initial experimentation involved testing the relative density and size error of the metal additive manufacturing process. Density measurement was performed using the Archimedes method, and further X-ray CT scanning was utilized to observe the internal structure and compactness. The outcomes indicate that suitable laser parameters yield favorable results in producing oscillating heat pipes, achieving good compactness and minimal dimensional error with proper parameter adjustments. Following relevant pre-processing and post-processing on the oscillating heat pipe, leakage experiments were conducted to ensure experimental accuracy. The oscillating heat pipe had dimensions of 120 mm in length and 51 mm in width, with five turns of 2 mm × 2 mm cross-sectional channels inside. Interval design was employed to address inter-channel thermal interaction commonly encountered in flat heat pipes for comparison. Methanol was selected as the working fluid to investigate the oscillating characteristics and thermal performance under different input powers (20 W, 30 W, 40 W, 60 W, 80 W). The results indicated that the inter-channel spacing can significantly decrease the lateral thermal interaction and enhance the oscillation effect during the operation of the oscillating heat pipe, resulting in improved thermal performance. The experiments demonstrated that at 20 W, the equivalent thermal conductivity of the heat pipes with and without inter-channel spacing was 2428 and 1743 (W/mK), respectively, and at 80 W, it was 2663 and 2511 (W/mK), respectively. These results indicate that reducing thermal interaction can significantly improve the oscillation effect, leading to higher equivalent thermal conductivity at low power.

Experimental design and characterization of Eu-doped tellurite matrix glassy composite for medical and ionizing-radiation sensing applications

This study experimentally presents the synthesis and characterisation of a new transparent Eu-doped tellurite matrix glassy composite with the view of predicting its UV and radiation sensing applications. This glassy composite, described by 50TeO2–15Na2O – 15ZnO – (20-x)PbO – xEu2O3 for x = 0 (TPEu-0), 1 (TPEu-1), 2 (TPEu-2), and 3 (TPEu-3) mol%, was prepared by the well-known melting-and- quenching technique. The glassy nature of the prepared samples was verified by the X-ray diffraction (XED) technique, and the density of the glasses was measured by the Archimedes method. The glasses’ optical features were determined from optical transmission and absorption spectra. In addition, the gamma radiation sensing and shielding prowess of the TPEu-X samples was determined from Monte Carlo simulation data using FLUKA code and direct calculations from the NISTXCOM database. The response of the glasses under UV-excitation was also analysed. The melting point and density of the glasses increased as the glasses was enriched with Eu2O3. The density of TPEu-X increased from 5.51 to 5.58 while the melting point grew from 750 °C to 1100 °C Eu2O3 concentration grew from 0 to 3 mol%. The increase in the concentration of Eu2O3 activated crystallization in the glass system. TPEu-1 has the highest optical bandgap energy (3.0 eV) and the lowest refractive index (2.39) among the TPEu-X glasses. The Eu2O3 content of the glasses affected their responses and appearance under UV light. Generally, the glass with the lowest Eu2O3 content possessed the least capacity to shield gamma radiation. The prepared TPEu-3 glass displayed the ability to displace many conventional and non-traditional shields in design of efficient radiation protection systems.

Preparation and electrical properties of pyrochlore R2(ZrTi)O7 for solid oxide fuel cell electrolyte

The electrolyte conduction is a factor that influences the power density of Solid oxide fuel cells (SOFCs). Pyrochlore phase is a superstructure of the fluorite, and it has an empty 8b site completely under ordered pyrochlore structure. Therefore, the pyrochlore structure oxides of R2(ZrTi)O7 series were considered that they might have potential to become an excellent SOFC electrolyte material in this report. R2(ZrTi)O7 (R = La, Nd, Sm, Eu, Gd, Dy, Y, Ho, Er and Yb) were made by mixed with Li2O flux and heat treatment by 1000 and 1400 °C. The crystal structures identified by XRD are all pyrochlore structures. The lattice parameters were obtained through Rietveld refinement. Scanning electron microscopy was used to observe microstructure directly and verify the relative density result which was obtained by Archimedes method. The Electrical properties of electrochemical impedance spectroscopy (EIS) were measured to compare with lattice parameters. Dy2(ZrTi)O7 has the highest conductivity of 5.37(1) × 10−4 S·cm−1 at 700 °C and Nd2(ZrTi)O7 has the lowest activation energy of 0.59(2) eV in R2(ZrTi)O7 series. Dy2(ZrTi)O7 was combined with carbonate to become composite material for electrical property observation and comparing with Dy2(ZrTi)O7.

Production of green, low-cost and high-performance anorthite-based ceramics from reduced copper slag

Waste slags are promising sources of ceramic materials, but slag-derived ceramics also show inferior whiteness and quite different constituents compared to commercial products due to the introduction of impurity elements. To solve this issue, in this work, reduced copper slag after iron and copper extraction was used as a new raw material to prepare novel anorthite-based ceramics. The role of slag addition in the sintering, microstructure, physical and mechanical properties, leaching behavior, and color quality was investigatedby using different characterization techniques such as DSC-TG, XRD, SEM, spectrophotometer, Archimedes method, 3-point bending method, and acetic acid buffer solution method. The results show that the ceramics are more effective in liquid generation with the slag addition, significantly enhancing the sintering and reducing the porosity. The slag also favors the development of anorthite grains as it is an Al2O3-SiO2-CaO-based system. As a result, a dense and well-bonded structure with few impurity phases and fine rounded pores is produced with 40 wt% of slag addition. These effects contribute to a remarkable improvement in flexural strength (87.6 MPa) and good maintenance of whiteness (∼90). Moreover, its leaching toxicity is ∼ 3 orders of magnitude lower than the thresholds. The high strength, appearance quality and cleanliness are the competitive advantages of the designed ceramics compared to other slag-derived ceramics. However, limited densification and severe blisters and bloating appear after introducing more than 50 wt% of slag, leading to a much inferior mechanical and color performance.

Experimental assessment for the photon shielding features of silicone rubber reinforced by tellurium borate oxides

In the present study, six silicone rubber doped by tellurium borate oxides were fabricated using the casting method. The densities of the fabricated silicon rubber-doped by tellurium borate oxides samples were measured using the Archimedes Method. Moreover, the linear attenuation coefficient of silicone rubber doped tellurium borate oxides samples was evaluated experimentally using the hyper pure germanium, and the recorded linear attenuation coefficient values were affirmed using the theoretical Phy-X program. The experimental measurements were performed using the narrow beam transmission method with radioactive isotopes Am-241, Cs-137, and Co-60 with energies of 59, 661, 1173, and 1332 keV. The linear attenuation coefficient values showed an enhancement by 4.73 times, 1.20 time, 1.17, time, and 1.17 time, respectively at gamma photon energies of 59, 661, 1173, and 1332 keV, when the TeO2 concentration increased in the fabricated composites from 0 to 50 wt%. The enhancement of the linear attenuation coefficient values has a positive effect on the transmission rate values where the half-value thickness and transmission rate were decreased accompanied by an increase in the RPE.

Tuning of smart cobalt doped borate glasses by electron beam as band-pass filters

CoO (0.2, and 0.7 wt%) doped lithium borate glass samples according to the composition of 84 % B2O3 + 12 % Li2O + 4 % Al2O3 have been prepared by melt quenching technique. Archimedes's method was used to compute the molar volumes of the formed glasses by measuring their density. For the purpose of analyzing the band-pass glass filter and UV-IR cut-off, the optical spectroscopic features of the obtained lithium borate glasses were evaluated over the entire wavelength range from 190 to 1100 nm. The effect of CoO doping ratios (0.2, and 0.7 wt%) on the optical properties of the prepared glass samples (refractive index, optical and electrical conductivity, reflection loss (RL), optical transmission (Toptical), extinction coefficient, permittivity, dielectric constants, electric susceptibility and polarizabilities) were studied. The decrease in ETauc and increase in UV–Visible cutoff range with the increase of CoO content is due to the increase of the non-bridging oxygen concentration. Co2+ ions are detected in both tetrahedral and octahedral positions in the glass matrix, according to the electron paramagnetic resonance EPR spectra. The transmittance data of the glass filters revealed that they have a broad band-pass in the Vis-NIR region. The electron beam irradiation showed an increase in the stopping range of the prepared glasses as band pass filters which makes them available for a wide-range of optical equipment including lenses and laser shields, as well as optoelectronic and photovoltaic apparatus.

Physicochemical, mechanical, dielectric, and biological properties of sintered hydroxyapatite/barium titanate nanocomposites for bone regeneration

Bone implants fabricated using nanocomposites containing hydroxyapatite (HA) and barium titanate (BT) show osteoconductive, osteoinductive, osteointegration, and piezoelectricity properties for bone regeneration applications. In our present study, HA and BT nanopowders were synthesized using high-energy ball-milling-assisted solid-state reaction with precursors of calcium carbonate and ammonium dihydrogen phosphate, and barium carbonate and titanium oxide powder mixtures, respectively. Hexagonal HA and tetragonal BT phases were formed after calcination at 700 and 1000 °C, respectively. Subsequently, hydroxyapatite/barium titanate (HA/BT) nanocomposites with different weight percentages of HA and BT were prepared by ball-milling, then compacted and sintered at two different temperatures to endow these bioceramics with better mechanical, dielectric, and biological properties for bone regeneration. Microstructure, crystal phases, and molecular structure characterizations of these sintered HA/BT nanocomposite compacts (SHBNCs) were performed using field-emission scanning electron microscopy, x-ray diffraction, and Fourier-transform infrared spectroscopy, respectively. Bulk density was evaluated using the Archimedes method. HA/BT nanocomposites with increased BT content showed enhanced dielectric properties, and the dielectric constant (ϵr ) value for 5HA/95BT was ∼182 at 100 Hz. Mechanical properties such as Vicker’s hardness, fracture toughness, yield strength, and diametral tensile strength were also investigated. The hemolysis assay of SHBNCs exhibited hemocompatibility. The effect of these SHBNCs as implants on the in vitro cytocompatibility and cell viability of MG-63 osteoblast-like cells was assessed by MTT assay and live/dead staining, respectively. 15HA/85BT showed increased metabolic activity with a higher number of live cells than BT after the culture period. Overall, the SHBNCs can be used as orthopedic implants for bone regeneration applications.

Effect of Powder Characteristics on Relative Density and Porosity Formation During Electron Beam Selective Melting of Al2024 Aluminum Alloy

Abstract Defects, such as pores and cracks, can be found in parts fabricated by powder-bed additive manufacturing techniques. The origin of certain defects, such as some voids, can be linked to initial powder quality, which makes it an important factor in the process. Powders used in additive manufacturing processes are produced by different methods such as gas atomization (GA), plasma atomization (PA), and plasma rotating electrode process (PREP); each gives different powder quality. In this study, two different Al2024 powders, produced by electrode induction GA and PREP techniques, were used to investigate the effect of powder characteristics on defect formation during electron beam melting process (EBM). Powders were first characterized by using Hall flowmeter funnel and scanning electron microscope (SEM); then, the EBM process was carried out, and finally, samples were examined by density measurement using Archimedes method, SEM analysis, and tensile test. PREP powder showed higher levels of sphericity and surface smoothness without attached satellites. Consequently, a higher apparent density and decreased flowing time were achieved in PREP powder. Moreover, gas-induced internal pores were observed in GA particles. The results also revealed the average relative density of 96.7% and 99.4% for the parts built by GA and PREP powders, respectively. SEM micrographs confirmed the results of density measurement of the fabricated parts and showed higher degrees of both spherical and irregular-shaped pores in samples built by GA powder. Additionally, they showed deprived mechanical properties due to the higher porosity contents which can form stress-concentrated areas.

Preparation and characterization of zinc–borate glasses doped with Ag2O

Using the melt quenching approach, glasses having the formula ZnO-B2O3-Ag2O have been created.Utilising the X-ray diffraction technique, the synthesized glass has been described. The Archimedes method was used to compute the densities of these glasses,and the appropriate formula was used to determine the associated molar volume.Absorption spectra were recorded using a UV–visible spectrometer.Tauc's figure has been used to examine the energy band gap.Ag2O concentration-related variations in band gap energy have been discussed.

X-ray computed tomography vs Archimedes method: a head-to-head comparison

Metal additive manufacturing (AM) is growing rapidly towards industrial adoption in various industries, but porosity remains a concern because it creates areas of stress that affects the mechanical properties and reduces reliability. Porosity can be quantified by X-ray computed tomography (XCT), but the method is relatively slow and expensive. The Archimedes density measurement method is widely used due to the low cost and ease of operation; however, it is limited in its precision for low porosity levels. In this work, a series of additively manufactured aluminium 6061-Ti6 alloy samples with different types and quantities of porosities are subjected to Archimedes, gas pycnometer and X-ray methods. This work clarifies the application range and limitations of each of these methods, using 10 mm cubes of Al 6061-Ti6 manufactured by laser powder bed fusion.

The detection of porous media volume using the modified Archimedes method

The detection of porous media volume using the modified Archimedes method

Carnauba leaf fibers: correlation among diametrical variation, physical and mechanical properties

The variability of properties presented by natural lignocellulosic fibers (NLFs) is an important issue to highlight, since such inconsistencies in their characteristics put them at a disadvantage when comparing them to synthetic materials. It is important to point out that the application of methodologies that make it possible to predict the behavior of NLFs in the face of mechanical stress is essential for the use of these materials in engineering applications. For this, the present study proposes to evaluate the influence of the carnauba fibers (Copernicia prunifera) morphology in the properties presented by these materials. Optical microscopy (OM) was applied to determine the cross-section and diametrical variation of the fibers, enabling the evaluation of density by Archimedes method according to the mean diameter of the fibers. The mechanical properties were evaluated by tensile testing and the data were acquired by Weibull analysis. The morphological aspects of the longitudinal and cross-sections of the fibers were evaluated with scanning electron microscopy (SEM). The fibers had an average density of 1.13 ± 0.22 g/cm3, with diameter intervals ranging from 0.31 to 1.21 mm. The fibers have reasonable mechanical properties, with an average tensile strength of 64.7 ± 40.9 MPa, Young's modulus of 1.37 ± 0.80 GPa and elongation of 5.59 ± 1.60%. The SEM micrographs highlighted the defects present on the outer surface of the fiber as well as in the cross-section. There was a high potential for the use of carnauba fibers in the manufacture of polymer matrix composites.

Ionic Equilibria in Polytungstate Melts

Polytungstate melts are used for the electrodeposition of oxide tungsten bronzes (OTBs). The scarce information on the ionic composition and properties of these electrolytes hinders effective control of the electrochemical synthesis of OTBs with desired electrical and optical properties. In this work, a comprehensive study of Na2WO4–WO3 melts that contained up to 55 mol% of tungsten trioxide was performed in the temperature range from 983 to 1073 K. Melt densities were measured using the Archimedes method. DFT calculations were carried out for various tungsten-containing compounds, including WxO3x−12+, WxO3x+12−, NaWxO3x+1−, and Na2WxO3x+1. The calculated values of the W–O bond energy indicate that the tested compounds are stable in the specified temperature range, and the WO22+ cation is the most stable. The experimental dependences of the redox potential on the mole fraction of tungsten trioxide in the Na2WO4–WO3 melt were obtained using the EMF method. A model that considers the processes of interaction between tungsten-containing ions and O2− ions was proposed for the quantitative interpretation of these dependences. The equilibrium constants were found through fitting according to the Levenberg–Marquardt algorithm. The effect of the WO3 mole fraction and temperature on the concentrations of WO42−, W2O72−, W3O102−, W4O132−, WO22+, and O2− ions was analyzed.

Effects of void content on the moisture uptake and mechanical strength of a glass/epoxy composite

The effect of voids on the moisture uptake and transverse modulus and strength of a unidirectional glass/epoxy composite has been examined. To create voids, a foaming agent was mixed with the liquid epoxy resin prior to infusion. Micrographs of polished cross-sections indicate that voids are close to spherical in shape appearing in the matrix and at the fiber/matrix interface. The fiber, matrix, and void contents were analyzed by micrograph, burn-off, and density (Archimedes) methods. The void contents in the void-free and void-containing composites were respectively close to zero and 21%. Specimens were immersed in distilled water at 40°C until saturation. The weight gain was monitored periodically. For the void-free specimens, saturation moisture contents of about 0.60%. The void-containing specimens absorbed much more water, about 5%. The Fickian diffusion model provided good fits to experimental data although the transport mechanism for the void-containing composite appeared non-Fickian. Young’s modulus of the void-free composite was slightly affected by water absorption, although, the transverse tensile strength dropped significantly. Voids were found to substantially reduce transverse modulus and strength about 70%, for both dry and water saturated specimens. Moisture content analysis was in good agreement with experiments for the void-free composite but over-predicted the moisture content for the voidcontaining composite. Micromechanics predictions of the transverse modulus were within 21% of the experimental results for void-free and void containing composites at dry and water saturated conditions.

Evaluation of nuclear transmutation effects due to beta decay on borosilicate glasses

AbstractIn the study of deep geological disposal of high‐level radioactive waste (HLW), beta decay has been widely studied, whereas the nuclear transmutation effects due to beta decay on vitrification are generally neglected. In this work, a series of sodium borosilicate glasses doped with cesium was fabricated. The nuclear transmutation due to beta decay evolving with the deposited time was simulated by substituting for cesium with barium. The macroscopic properties of the glasses, including density, hardness, and Young's modulus, were measured using the Archimedes (buoyancy) method and nanoindentation, respectively. The microscopic structures of the glasses were characterized by grazing incident X‐ray diffraction, infrared spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, and Raman spectroscopy. The nuclear transmutation effects were significant. With the substitution of barium for cesium, the density, hardness, and modulus of the glasses increased and eventually tended to saturation. A decrease of [BO3] units and an increase of [BO4] units were observed in the infrared spectra and NMR spectra. In addition, the results were systematically compared to previous strontium‐doping work in order to evaluate nuclear transmutation effects due to beta decay on vitrification in HLW comprehensively. The comparison demonstrated that the nuclear transmutation effect of cesium is completely opposite to that of strontium. The research is expected to contribute to a deeper understanding on the nuclear transmutation effects due to beta decay in HLW on vitrification.

DETERMINATION OF THE VOLUME FRACTION OF THE MICROPOROSITY IN NICKEL-BASED SUPERALLOY SINGLE CRYSTALS

Microporosity is a dangerous defect of single crystal gas turbine blades cast from nickel-based superalloys (NBS). The volume fraction of the porosity in single crystal alloys does not exceed a few tenths of a percent, however, it can result in manyfold shortening of the lifetime of the blade material under fatigue loading. We present the results of determining the volume fraction of the porosity in single crystal NBS. Single crystals of NBS CMSX-4 obtained according to the industrial technology of manufacturing the single crystal blades of gas turbines were used as a test object. It is found that the applied methods, with the exception of optical microscopy, have an accuracy sufficient for measuring the volume fraction of the microporosity of about 0.2 %vol. The highest accuracy with a statistical error of about ±0.01 %vol. was attained using the Archimedes method using distilled water as a liquid. The method provides the determination of small (up to a few hundredths of a percent by volume) increase of the porosity during high-temperature creep. The results obtained can be used for precise determination of the porosity in NBS single crystals before and after service. Moreover, the process of high-temperature creep can be modeled using a correlation relationship between an increase in the porosity of single crystal material and the accumulated creep strain.

Additive manufacturing design approach to strut-based functionally graded porous structures for personalized implants

This study aims to create mathematical models (MMs) and maps that will facilitate personalized implant design and provide the selection of design parameters that give desired mechanical and physical properties. For this purpose, strut-based functionally graded porous structures (FGPSs) were designed using three different unit cell structures, unit cell sizes, and strut thicknesses. A total of nine specimens were produced by L-PBF using Ti-6Al-4V. The porosities were measured by dry weighing and Archimedes methods. In addition, three MMs were derived that give the effective porosity of the specimens based on the unit cell structures. A relationship was established between the modulus of elasticity obtained from the compression test and the design parameters. MMs that give the elastic modulus and porosity of FGPSs depending on unit cell size and strut thickness have been derived. By using these models, maps giving the mechanical and physical properties of the functionally graded porous structures were generated. Thanks to these models and maps, personalized implant design will be facilitated, and biocompatibility will be increased. Thus, undesired problems such as early revision and repetitive surgeries will be minimized and the quality of life of the patients will be increased.

Investigation of ABS–oil palm fiber (Elaeis guineensis) composites filament as feedstock for fused deposition modeling

Purpose The purpose of this paper is to investigate the tensile strength, Young’s modulus, dimensional stability and porosity of acrylonitrile butadiene styrene (ABS)–oil palm fiber composite filament for fused deposition modeling (FDM). Design/methodology/approach A new feedstock material for FDM comprising oil palm fiber and ABS as a matrix was developed by a twin screw extruder. The composite filament contains 0, 3, 5 and 7 Wt.% of oil palm fiber in the ABS matrix. The tensile test is then performed on the fiber composite filament, and the wire diameter is measured. In this study, the Archimedes method was used to determine the density and the porosity of the filament. The outer surface of the wire composite was examined using an optical microscope, and the analysis of variance was used to assess the significance and the relative relevance of the primary factor. Findings The results showed that increasing the fiber loading from 0.15 to 0.4 MPa enhanced tensile strength by 60%. Then, from 16.1 to 18.3 MPa, the Young’s modulus rose by 22.8%. The density of extruded filament decreased and the percentage of porosity increased when the fiber loading was increased from 3 to 7 Wt.%. The diameter deviation of the extruded filaments varied from −0.21 to 0.04 mm. Originality/value This paper highlights a novel natural resource-based feedstock material for FDM. Its mechanical and physical properties were also discovered.

Electrical, Microstructural and Physical Characteristics of Talc-based Cordierite Ceramics

The aim of this work is to study the effect of various talc rocks for the preparation of talc-based cordierite ceramics. Raw talc and sintered cordierite-based ceramic samples (1000-1375ºC for 2 h) were characterized using XRD, XRF, TGA-DTG, laser PSDs, Archimedes method, SEM-EDAX and dielectric relaxation spectrometer (DRS). Results show that impurity oxide contents, particle size and mineralogical changes of green batches influenced the microstructure densification and crystallization of orthorhombic and hexagonal cordierite. The complex electric modulus plot shows the existence of two relaxation processes associated with the capacitive contribution grain boundaries and grain at low and high frequencies, respectively. The dielectric loss reached much lower values (0.0004–0.0007) for the ceramics composed of higher cordierite phase composition (87.00 to 92.00wt.%) that sintered at 1350 and 1375ºC. Such ceramics could be promising in electronic applications like capacitors, microwave devices and wireless communication.

Microstructure and Elastic Properties of Hydroxyapatite/Alumina Nanocomposites Prepared by Mechanical Alloying Technique for Biomedical Applications

Although hydroxyapatite (HA) has exceptional biological qualities that inspire researchers to employ it as an appealing biomaterial for various purposes, its usage in hard tissue replacement applications is severely restricted because of its fragility. In order to create nanocomposites with the necessary mechanical properties for biomedical applications, HA was produced, and various amounts of alumina (Al2O3) were added to it. Additionally, the phase composition of the powdered nanocomposites was examined using the X-ray diffraction (XRD) technique. Crystal sizes, lattice strain, and dislocation density were all estimated as well. In order to measure the produced nanocomposite powders’ physical and elastic characteristics using the Archimedes method and ultrasonic non-destructive technique, they were then pressed and sintered at 1000 °C. The resulting information made it clear that further increases in the weight percentages of Al2O3 resulted in a 10.25, 25.64, and 33.33% reduction in crystal size. As a result of adding more Al2O3-up to 20 weight, percent-the results also showed that this properties-microhardness, compressive strength, Young’s modulus, elastic modulus, bulk modulus, shear modulus, and Poisson’s ratio-were improved by 109, 36.29, 95.5, 100.59, 104.97, 92.84 and 9.5%, respectively. Unfortunately, it increased its porosity by considerable amounts. It might be argued that the generated nanocomposites are favorable for biomedical applications.