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Extension of the feeders and high power demand have resulted in more substantial power dissipation and reduced voltage decline. Therefore, minimizing power loss and enhancing the voltage profile are imperative for efficient energy distribution. This research introduces a novel approach called the Hybrid Archimedes Optimization Algorithm (HAOA), which combines the Levy flight and Archimedes Optimization Algorithm (AOA) to improve the performance of AOA. AOA replicated the upward impulse described by Archimedes principle in physics and experienced an imbalance between exploitation and exploration. Utilizing Levy flight results in an improved balance between exploration and exploitation, enhancing algorithm performance in finding optimal solutions. Therefore, hybridizing Levy flight with AOA to enhance its performance results in an improved trajectory balance between exploration and exploitation. This trajectory is utilized to update the object's position in AOA and is regarded as a feasible method to enhance the slow performance of AOA. The HAOA algorithm was employed to optimize network reconfiguration to decrease power loss and voltage deviation (VD) and improve the voltage stability index (VSI) in radial distribution networks (RDN). The validation of HAOA was assessed using the IEEE 33 and 69 bus systems. The power loss for the IEEE 33 and 69 test systems dropped to 139.55 and 98.459 kW, respectively, compared to the base case values of 202.677 and 224.96 kW. The VD for the 33 and 69 bus systems is 0.00134 and 0.000306 p.u, respectively, compared to the base case values of 0.0035498 and 0.001443 p.u. The VSI has been enhanced to 0.785 p.u for the 33 bus system and 0.8126 p.u for the 69 bus system following the reconfiguration. The results indicate that HAOA outperforms other approaches in terms of lower power, VD, and voltage stability enhancement. [ABSTRACT FROM AUTHOR]

Sintered porous mullite-alumina ceramics are obtained from the concentrated suspension of powdered raw materials such as kaolin, gamma and alpha Al2O3, and amorphous SiO2, mainly by a solid-state reaction with the presence of a liquid phase. The modification of mullite ceramic is achieved by the use of micro- and nanosize TiO2 powders. The phase compositions were measured using an X-ray powder diffraction (XRD) Rigaku Ultima+ (Tokyo, Japan) and microstructures of the sintered specimens were analysed using scanning electron microscopy (SEM) Hitachi TM3000-TableTop (Tokyo, Japan). The shrinkage, bulk density, apparent porosity, and water uptake of the specimens was determined after firing using Archimedes' principle. The apparent porosity of the modified mullite ceramic is 52–69 ± 1%, water uptake is 33–40 ± 1%, pore size distributions are 0.05–0.8 μm, 0.8–10 μm and 10–1000 μm, and bulk density are variated from 1.15 ± 0.05 to 1.4 ± 0.05 g/cm3. The microsize TiO2 and nanosize TiO2 speed up the mullitisation process and allow the decrease in the quantity used as raw material amorphous SiO2, which was the purpose of the study. The use of nanosize TiO2 additive increases the porosity of such a ceramic, decreasing the bulk density and linear thermal expansion. [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM) is a disruptive technology that provides design freedom, fast turnaround times, and a digital workflow. However, reliable mechanical and material properties are crucial for medical implants and devices produced by AM. The laser powder bed fusion (LPBF) echnique is a reliable method for producing high-quality parts with excellent mechanical properties. The presence of internal porosity, however, is one of the most significant problems in SLM part production. This study aimed to determine the relative density of components produced by LPBF and to develop a method for accurately quantifying the relative density. Three powders were used to evaluate the efficacy of three different quantification methods. The OR-Laser Creator LPBF unit was used to manufacture them. After production, all nine samples were polished on a lathe, and the relative density was measured using three different quantification methods. The results of this study showed that the Archimedes principle is the most accurate and reliable method for determining the density of materials used in LPBF. The findings of this study should help to ensure that the quality of parts produced by SLM is reliable and accurate. This should increase confidence in the use of LPBF in the medical industry and other industries where AM components have a significant advantage. [ABSTRACT FROM AUTHOR]

In this work, dysprosium (Dy3+) and europium (Eu3+) rare earth (RE) ion co-doped bismuth borate glasses with different alkali fluorides (Li+, Na+, and K+) and Al3+ ions were prepared by the melt quenching technique. Various techniques were carried out to investigate the impact of alkali fluorides on the luminescence properties of the prepared mixed rare earth ion (Dy3+ and Eu3+) glasses. The glassy nature was confirmed by the presence of humps in x-ray diffraction patterns. Density and molar volume were calculated via Archimedes principle to examine physical properties, which shows a decreasing trend from 5.30 to 3.34 in density with the addition of alkali fluorides. Fourier transform infrared spectroscopy was used to study the structural properties, and revealed the presence of traditional bismuth and borate groups along with metallic and cationic vibrations of alkali and RE ions. Ultraviolet–visible and near-infrared absorption spectroscopy was performed to investigate the optical properties. The indirect optical bandgap was estimated and displayed an increasing trend from 2.88 to 3.34 eV, which confirmed the suitability of this material for use in optoelectronic devices. With alkali fluorides, the Urbach energy was decreased from 0.25 to 0.14 eV, which indicated a smaller number of defects. To assess the luminescent behaviour, photoluminescence spectroscopy was executed to record both excitation and emission spectra of glasses for a variety of excitation wavelengths. Under varying excitations, the synthesized glasses showed three distinct emissions in the blue, yellow, and red regions. The primary sources of the blue and yellow emission were the Dy3+ ion transitions 4F9/2 → 6H15/2 and 6H13/2, whereas the red emission was produced by the Eu3+ ion transition 5D0 → 7F2. Colorimetric analysis was carried out on the emission spectra, and colour parameters were obtained. The CIE (Commission Internationale de l'Eclairage) colour coordinates of composition DEABB were identified as (0.32, 0.32), which lie closest to white light coordinates (0.33, 0.33). This confirmed that the prepared samples demonstrated excellent emission properties and could be proposed for use as white light and orange-red light sources in solid-state lighting applications. [ABSTRACT FROM AUTHOR]

Feature selection is an active research area in data mining and machine learning, especially with the increase in the amount of numerical data. FS is a search strategy to find the best subset of features among a large number of subsets of features. Thus, FS is applied in most modern applications and in various domains, which requires the search for a powerful FS technique to process and classify high-dimensional data. In this paper, we propose a new technique for dimension reduction in feature selection. This approach is based on a recent metaheuristic called Archimedes' Optimization Algorithm (AOA) to select an optimal subset of features to improve the classification accuracy. The idea of the AOA is based on the steps of Archimedes' principle in physics. It explains the behavior of the force exerted when an object is partially or fully immersed in a fluid. AOA optimization maintains a balance between exploration and exploitation, keeping a population of solutions and studying a large area to find the best overall solution. In this study, AOA is exploited as a search technique to find an optimal feature subset that reduces the number of features to maximize classification accuracy. The K-nearest neighbor (K-NN) classifier was used to evaluate the classification performance of selected feature subsets. To demonstrate the superiority of the proposed method, 16 benchmark datasets from the UCI repository are used and also compared by well-known and recently introduced meta-heuristics in this context, such as: sine-cosine algorithm (SCA), whale optimization algorithm (WOA), butterfly optimization algorithm (BAO), and butterfly flame optimization algorithm (MFO). The results prove the effectiveness of the proposed algorithm over the other algorithms based on several performance measures used in this paper. [ABSTRACT FROM AUTHOR]

Glasses with compositions 46.1B2O3-24.4Na2O-26.9CaO.2.6P2O5, xZnO/MgO-22.0B2O3-(24.4-x)Na2O-27CaO-2.5P2O5 (x = 2.5, 3 mol%) and 1.5ZnO-1.5MgO-22.0B2O3-21.5.Na2O-27CaO-2.5P2O5 were melted by melt quenching technique. The densities of the glasses were measured by the Archimedes principle, using an analytical scale. Glasses possess densities in the 2.538 to 2.623 g cm-1 range. The short-range order was also discussed from the molar volume Vm, cm3 mol-1, and oxygen packing density point of view. The molar volume of the glasses varies between 26.566 - 27.420 cm3 mol-1 and the oxygen packing density is between 73.669 to 76.262 mol cm-3x. The Furie transform infrared spectroscopy and Raman spectroscopy were performed to study the main structural units constituting the structure of the samples. The main structural units were found to be BO3 and BO4 probably connected in pentaborate and triborate structural units. The influence of the ZnO and MgO on the structure and chemical bonding of the glasses was discussed. [ABSTRACT FROM AUTHOR]

This paper explores the effect of waste rubber grain size on the porosity, modulus of elasticity, thermal properties, and soundproofing performance of polymer composites with different thicknesses (10, 15, and 20 mm). All properties were tested in accordance with European standards, with the exception of porosity, which was measured using Archimedes' principle. The findings indicate that with a consistent amount of polyurethane glue, finer rubber grains result in composites with higher porosity, leading to a lower modulus of elasticity but enhanced thermal and sound insulation. In contrast, coarser rubber grains produced composites with lower porosity and a higher modulus of elasticity, though with slightly reduced thermal insulation and significantly worse soundproofing. A combination of fine and coarse rubber grains provided a balanced performance, offering both good thermal and sound insulation while maintaining a high modulus of elasticity. Among the thicknesses tested, 15 mm was identified as optimal, combining a relatively high modulus of elasticity, low thermal conductivity, and better airborne sound insulation index. Future research will focus on applying this composite in concrete building products that meet noise protection and energy efficiency standards. [ABSTRACT FROM AUTHOR]

Abstract In the present work, a glass system with developed composition consisting of B2O3, ZnO, Na2O and Fe2O3 samples has been investigated. Glass samples were prepared using the melt quenching method and the density of the system was measured using Archimedes’ principle. Spectroscopic analysis using a gamma source and a high-purity germanium detector at four energies of 0.0595, 0.6617, 1.173, and 1.333 MeV emitted from Am-241, Cs-137, and Co-60 were used to determine the attenuation parameters of present glass composites. The sample containing 45 B2O3 + 10 Na2O + 40 ZnO + 5 Fe2O3 (coded BNZF-4) had the highest mass attenuation coefficient (MAC) value at all the energies discussed compared to the other composites. Whoever, the BNZF-1 sample had the lowest value at all ranges of energies. The transmission factors (TF, %) of the manufactured samples were calculated, at 0.0595 MeV (TF, %) values are 32.6429 and 6.4612 for samples BNZF-1 and BNZF-4, respectively. The statistical results demonstrated significantly better to increase the ZnO concentration in the sample, where the percentage of zinc oxide inside the prepared glass samples has the following direction BNZF -4 > BNZF -3 > BNZF -2 > BNZF -1. The significance of this study is that transparent, environmentally harmless glass composites with relatively high density have been prepared that can be used as shielding materials against gamma rays, especially at low energies.

We consider three different systems in a heat flow: an ideal gas, a van der Waals gas, and a binary mixture of ideal gases. We divide each system internally into two subsystems by a movable wall. We show that the direction of the motion of the wall, after release, under constant boundary conditions, is determined by the same inequality as in equilibrium thermodynamics d U − đ Q ≤ 0 . The only difference between the equilibrium and non-equilibrium laws is the dependence of the net heat change, đ Q , on the state parameters of the system. We show that the same inequality is valid when introducing the gravitational field in the case of both the ideal gas and the van der Waals gas in the heat flow. It remains true when we consider a thick wall permeable to gas particles and derive Archimedes' principle in the heat flow. Finally, we consider the Couette (shear) flow of the ideal gas. In this system, the direction of the motion of the internal wall follows from the inequality d E − đ Q − đ W s ≤ 0 , where d E is the infinitesimal change in total energy (internal plus kinetic) and đ W s is the infinitesimal work exchanged with the environment due to the shear force imposed on the flowing gas. Ultimately, we synthesize all these cases within a general framework of the second law of non-equilibrium thermodynamics. [ABSTRACT FROM AUTHOR]

This document is a compilation of research articles and reviews on the mechanical behavior and applications of natural fiber-reinforced polymer composites. The articles cover various topics, including the effect of fillers on mechanical properties, the use of natural and industrial wastes as fillers, and the characterization of different types of fiber-reinforced composites. The studies explore the potential of using natural fibers and fillers to improve the mechanical properties of composites and discuss the use of seashell waste and other unconventional fillers in composite materials. The document provides valuable insights into the field of natural fiber-reinforced polymer composites and highlights recent developments and challenges in this area. [Extracted from the article]

This study addresses a research gap in composite material development by exploring the potential of innovative waste materials to enhance performance. An innovative and cost‐effective waste material serves as a reinforcing agent, with cenosphere and molybdenum disulphide used in proportions ranging from 0% to 4%. Employing a cost‐effective stirring cast technique, composites are fabricated, combining AA7075 alloy with cenosphere particles (AA7075/cenosphere) and molybdenum disulphide particles (AA7075/MoS2). The experimental design, utilizing a central composite design within the response surface methodology framework, examines the weight percentages of cenosphere and MoS2. Scanning electron microscopy reveals strengthening chemicals within the matrix, confirmed by electronic dispersive X‐ray spectroscopy for individual reinforcements in the aluminium alloy matrix. Density determination follows Archimedes' principle and the OIML G14 standard, while mechanical properties (hardness and ultimate tensile strength) are assessed per ASTM standards. Results demonstrate a significant reduction in composite density with cenosphere reinforcement, while molybdenum disulphide marginally affects density. The incorporation of reinforcements notably enhances both hardness and ultimate tensile strength. In conclusion, this research bridges a composite material development gap, presenting a novel and sustainable approach. By showcasing the potential of unconventional waste materials, the study contributes valuable insights to material science and engineering, opening new avenues for future research. [ABSTRACT FROM AUTHOR]

Background: Body mass and surface area are among the most important biological properties, but such information is lacking for some extant organisms and most extinct species. Numerous methods have been developed for body size estimation of animals for this reason. There are two main categories of mass-estimating approaches: extant-scaling approaches and volumetric-density approaches. Extant-scaling approaches determine the relationships between linear skeletal measurements and body mass using regression equations. Volumetric-density approaches, on the other hand, are all based on models. The models are of various types, including physical models, 2D images, and 3D virtual reconstructions. Once the models are constructed, their volumes are acquired using Archimedes' Principle, math formulae, or 3D software. Then densities are assigned to convert volumes to masses. The acquisition of surface area is similar to volume estimation by changing math formulae or software commands. This article presents a new 2D volumetric-density approach called the cross-sectional method (CSM). Methods: The CSM integrates biological cross-sections to estimate volume and surface area accurately. It requires a side view or dorsal/ventral view image, a series of cross-sectional silhouettes and some measurements to perform the calculation. To evaluate the performance of the CSM, two other 2D volumetric-density approaches (Graphic Double Integration (GDI) and Paleomass) are compared with it. Results: The CSM produces very accurate results, with average error rates around 0.20% in volume and 1.21% in area respectively. It has higher accuracy than GDI or Paleomass in estimating the volumes and areas of irregular-shaped biological structures. Discussion: Most previous 2D volumetric-density approaches assume an elliptical or superelliptical approximation of animal cross-sections. Such an approximation does not always have good performance. The CSM processes the true profiles directly rather than approximating and can deal with any shape. It can process objects that have gradually changing cross-sections. This study also suggests that more attention should be paid to the careful acquisition of cross-sections of animals in 2D volumetric-density approaches, otherwise serious errors may be introduced during the estimations. Combined with 2D modeling techniques, the CSM can be considered as an alternative to 3D modeling under certain conditions. It can reduce the complexity of making reconstructions while ensuring the reliability of the results. [ABSTRACT FROM AUTHOR]

Students often face difficulties to understand Archimedes’ principle and to apply it in everyday life. It is therefore necessary to explore a different teaching approach that addresses students’ visual and auditory senses in a unique manner. The aim of this study was to determine the effect of using multiple representations on undergraduate physics students' understanding of Archimedes' principle. A quasi-experimental approach was employed, involving the random selection of four groups of students (experimental and control) with two iterations, each involving two groups of students. A sample of 128 students completed an open-ended questionnaire based on the Thermal Transport Conceptual Inventory, and the Fluid Mechanics Concept Inventory. Lesson plans were presented for both iterations. Quantitative analysis involved the use of t-tests to assess the comparability of the groups, prior to the intervention and ANCOVA after the intervention to determine the effect. Qualitative data analysis involved identifying and comparing themes to establish student understanding before and after the two iterations. The findings indicated that the use of six different representations did not yield a significant effect compared to traditional teaching, while the use of eight representations proved significantly effective where the static pictures were replaced by animation pictures as well as adding videos and virtual labs. Careful planning is crucial not only for selecting the most suitable representation in a particular teaching situation, but also for determining which technology to use when addressing students’ understanding of Archimedes' principle.

OBJECTIVE: Compare 3 methods of nucleus pulposus (NP) volume measurement using the rabbit lumbar spines as a preclinical model to determine the effectiveness of prophylactic intervertebral disk fenestration in dogs. ANIMALS: Twelve 9-month-old, skeletally mature female entire New Zealand White rabbits weighing between 3.5 to 4.5 kg. METHODS: NP volume measurements of dissected rabbit lumber spines between L1 and L6 were made and compared using gross measurements, reconstructed MRI images, and water volumetry based on Archimedes' principle. Water volumetry was used as the true gold standard volume measurement in this study. RESULTS: The true volume (mean ± SD) of the nucleus pulposus NP as measured by water volumetry increased caudally from L1/L2 (16.26 ± 3.32 mm³) to L5/L6 (22.73 ± 6.09 mm³). Volume estimates made by MRI were significantly higher than those made using water volumetry at all sites (L1/L2 [P = .044], L2/L3 [P = .012], L3/L4 [P = .015], L4/L5 [P < .001], and L5/L6 [P < .001]). Gross measurements also significantly overestimated volume when compared to water volumetry at all sites; L1/L2 (P = .021), L2/L3 (P = .025), L3/L4 (P = .001), L4/L5 (P < .001), and L5/L6 (P < .001). MRI and gross volume estimates were significantly different at L4/L5 (P = .035) and L5/L6 (P = .030). CLINICAL RELEVANCE: The findings of this preclinical model might be relevant to veterinary surgeons who perform prophylactic fenestration for which there is no reliable method to determine the amount of NP to be removed. Preclinical ex vivo and in vivo fenestration studies with pre- and postoperative NP volume assessment are required. [ABSTRACT FROM AUTHOR]

Binary blends of unsaturated polyester (70%) and nitrile rubber (NR) (30%) and their composites are prepared. Zinc oxide nanoparticles (ZnONPs) were used as a filler in the hand-lay method. ZnONP weight ratios ranged from 0 to 3 wt.%. The ZnONPs were characterised using techniques such as X-ray diffraction (XRD) and scanning electron microscopy (SEM) to examine their crystalline structure and shape. The thermal and dielectric properties of the samples were examined as a function of filler content. Additionally, the theoretical and experimental densities of the nanocomposites were examined using the mixing rule and Archimedes’ principle, respectively. The thermal conductivity and diffusivity values exhibited variations between increasing and decreasing trends as the filler concentrations increased. Among all samples tested, the one containing 2.5% ZnONPs demonstrated the highest thermal conductivity and the lowest diffusivity when compared to the pure blend. As the ZnONP weight ratio increased, the corresponding dielectric constant value rose linearly, while the resistivity decreased linearly. Thermogravimetric analysis (TGA) revealed a significant improvement in the level of char yield and thermal stability of nanocomposites with increasing ZnONP concentration in the matrix. [ABSTRACT FROM AUTHOR]

Fe/Cu-based sintered friction materials are proven potential materials for heavy-duty applications. The current research explores the influence of rare earth oxide (Nd2O3) and graphite on the tribological characteristics of Fe/Cu-based friction materials. The constituents present in the friction material are Fe, Cu, Cg (1%, 3%, 5%, 7%), BaSO4, and Nd2O3 (5%). Optical microscopy and elemental mapping studies reveal the homogeneous distribution of elements in the matrix. Sintered density of the specimens showed a maximum of 70% of the theoretical density measured by Archimedes' principle. XRD analysis shows no new phase formation in all the sintered specimens. A peak microhardness result of 96 HV is obtained in specimen NG-01. The pin-on-disc tribotests are performed at an axial load of 50 N at a sliding velocity of 5.5 m/s. Specimen NG-03 with 3% graphite exhibited an optimum wear rate with a friction coefficient of 0.45. The surface morphology and elemental composition of the worn specimens are investigated. The morphological features inferred that the wear mechanism is predominantly mixed abrasive and adhesive. [ABSTRACT FROM AUTHOR]

Although various optimization algorithms have been widely employed in multiple applications, the traditional Archimedes optimization algorithm (AOA) has presented imbalanced exploration with exploitation phases and the propensity for local optima entrapment. Therefore, this article identified various continuous-time Hammerstein models based on an improved Archimedes optimization algorithm (IAOA) to address these concerns. The proposed algorithm employed two principal modifications to mitigate these issues and enhance identification accuracy: (i) exploration and exploitation phase recalibrations using a revised density decreasing factor and (ii) local optima entrapment alleviation utilizing safe experimentation dynamics. Various advantages were observed with this proposed algorithm, including a lower number of coefficient criteria, improved accuracy in Hammerstein model identification, and diminished processing demands by reducing gain redundancy between nonlinear and linear subsystems. This proposed algorithm also discerned linear and nonlinear subsystem variables within a continuous-time Hammerstein model utilizing input and output data. The process was evaluated using a numerical example and two practical experiments [twin-rotor system (TRS) and electro-mechanical positioning system (EMPS)]. Several parameters were then analyzed, such as the convergence curve of the fitness function, frequency and time domain-related responses, variable deviation index, and Wilcoxon's ranksum test. Consequently, the proposed algorithm reliably determined the most optimal design variables during numerical trials, demonstrating 54.74 % mean fitness function and 75.34 % variable deviation indices enchantments compared to the traditional AOA. Improved mean fitness function values were also revealed in the TRS (11.63 %) and EMPS (69.63 %) assessments, surpassing the conventional algorithm. This proposed algorithm produced solutions with superior accuracy and consistency compared to various established metaheuristic strategies, including particle swarm optimizer, grey wolf optimizer, multi-verse optimizer, AOA, and a hybrid optimizer (average multi-verse optimizer-sine-cosine algorithm). [ABSTRACT FROM AUTHOR]

Students often face difficulties to understand Archimedes' principle and to apply it in everyday life. It is therefore necessary to explore a different teaching approach that addresses students' visual and auditory senses in a unique manner. The aim of this study was to determine the effect of using multiple representations on undergraduate physics students' understanding of Archimedes' principle. A quasiexperimental approach was employed, involving the random selection of four groups of students (experimental and control) with two iterations, each involving two groups of students. A sample of 128 students completed an open-ended questionnaire based on the Thermal Transport Conceptual Inventory, and the Fluid Mechanics Concept Inventory. Lesson plans were presented for both iterations. Quantitative analysis involved the use of t-tests to assess the comparability of the groups, prior to the intervention and ANCOVA after the intervention to determine the effect. Qualitative data analysis involved identifying and comparing themes to establish student understanding before and after the two iterations. The findings indicated that the use of six different representations did not yield a significant effect compared to traditional teaching, while the use of eight representations proved significantly effective where the static pictures were replaced by animation pictures as well as adding videos and virtual labs. Careful planning is crucial not only for selecting the most suitable representation in a particular teaching situation, but also for determining which technology to use when addressing students' understanding of Archimedes' principle. [ABSTRACT FROM AUTHOR]

A study was carried out about the processing parameters influence of an AlSi10Mg part manufactured by a selective laser melting process in order to determine its optimal values and improve density and mechanical performance. For this purpose, a design of experiment (DoE) was realized by the Taguchi method selecting a set of appropriate processing parameters (9 combinations), resulting in 45 samples whose relative densities were measured by Archimedes' principle and metallographic image digital processing. The results showed that a relative density of up to 99.65% was achieved from raw data. While the statistical model by the Taguchi method indicated a comprehensive relationship between process parameters based on relative density, laser power was of major significance among the parameters. The Taguchi model suggested new values of process parameters, achieving AlSi10Mg parts with 99.98% of relative density. To contrast the mechanical properties of both optimized and non-optimized parts, they were characterized by tension testing. [ABSTRACT FROM AUTHOR]

Aluminum alloy processing via additive manufacturing (AM) technologies has increased in usage during the last decade. AM now enables manufacturing complex geometries not previously achieved through traditional manufacturing. Aluminum is usually processed using laser powder bed fusion (LPBF) technologies, which are used to manufacture metallic components of high geometrical complexity and dimensional accuracy and good mechanical, electrical, and chemical properties, which is why this technology is quite popular at industrial levels. To further develop quality control systems and new aluminum alloys using LPBF, there is a need to establish a predictive relationship between the parameters of the material. A study was carried out to investigate the relationship between energy density and process parameters such as laser power, scan speed, hatch spacing, scan pattern, and laser focus and its influence on the densification mechanism in additively manufactured components with aluminum alloys. AA6061 was selected due to its wide usage in different industries, given its low density and high mechanical performance. Relative density was analyzed using the Archimedes principle, and the quality and morphology of the AA6061 powder were analyzed through metallographic analysis. The process parameter selection was performed according to the best results obtained according to the laser power and energy density factors. The best manufactured samples had an energy density between 30 and 40 J/mm3, with relative densities above 99%. [ABSTRACT FROM AUTHOR]

In endocrine surgery, a precise ultrasonographic measurement of thyroid volume is crucial. However, there is limited comparative research between ultrasonographic and specimen volumes, which has left this issue open to debate. This study aims to assess the accuracy of recommended formulas for ultrasonographic thyroid volume measurement by comparing them to specimen volumes and analyzing the influencing variables. From the data of 120 eligible patients, different formulas, including ultrasonographic thyroid volume (US-TV) based on the ellipsoid formula, lower correction factor thyroid volume (LCF-TV), and calculated ultrasonographic (derived formula) thyroid volume (CU-TV), were used to estimate the thyroid volume based on measurements taken prior to surgery. These measurements were compared with the intraoperative specimen volume (IO-TV) derived using Archimedes' principle. According to our findings, the mean values for US-TV and LCF-TV were significantly lower, whereas CU-TV was higher than IO-TV. Deviations were more significant in patients who had surgery for benign indications or compressive symptoms and in those with suppressed thyroid-stimulating hormone levels. Although the ellipsoid formula tends to underestimate the actual thyroid volume, it remains the most accurate method for measuring ultrasonographic thyroid volume. The deviation is greater for larger volumes. [ABSTRACT FROM AUTHOR]

This paper presents the influence of the Hot Isostatic Pressing (HIP) process on the structure, mechanical properties and corrosion resistance of padding welds made using the TIG method from aluminium bronzes—CuAl7 and CuAl2 (a composite bundled wire). The tested CuAl7 material was a commercial welding wire, while the CuAl2 composite was an experimental one (a prototype of the material produced in multiwire technology). The wire contains a bundle of component materials—in this case, copper in the form of a tube and aluminium in the form of rods. The padding welds were manufactured for both the CuAl7 wire and the CuAl2 multiwire. The prepared samples were subjected to the Hot Isostatic Pressing (HIP) process, chemical composition tests were performed, and then the samples were subjected to observations using light microscopy, Vickers hardness testing, electrical conductivity tests, and apparent density determination using Archimedes' Principle. Tribological tests (the 'pin on disc' method) and neutral salt spray corrosion tests were conducted. The padding weld made of CuAl2 multifiber material subjected to the HIP process is characterized by an improvement in density of 0.01 g/cm3; a homogenization of the hardness results across the sample was also observed. The average hardness of the sample after the HIP process decreased by about 15HV, however, the standard deviation also decreased by about 8HV. The electrical conductivity of the CuAl2 welded sample increased from 16.35 MS/m to 17.49 MS/m for the CuAl2 sample after the HIP process. As a result of this process, a visible increase in electrical conductivity was observed in the case of the wall made of the CuAl2 multiwire—an increase of 1.14 MS/m. [ABSTRACT FROM AUTHOR]

Aermet 100 is a high-alloy steel with exceptional fracture toughness (minimum 110 MPa-m.5) and high strength-to-weight ratio. It also has good weldability. Therefore, it is good candidate material for the laser powder bed fusion process (L-PBF). L-PBF parameters were optimized for high density according to image analysis and Archimedes' principle. Then, tensile testing was performed on specimens made with the parameters which produced high density. After the process parameters and heat treatment were optimized, the tensile and yield strength of the specimens met the wrought requirement. However, ductility was much lower than typical wrought, although it was near the minimum requirement. There were random defects which exceeded 100 microns on the fracture surface of the tensile specimens and in the microstructure. The defects are likely attributed to the large and irregularly shaped powder particles which can effect powder packing and increase spatter formation. [ABSTRACT FROM AUTHOR]

Glass–ceramic nanocomposites (GCNs) of (10 − x) BaTiO3 (BT)–xPbTiO3 (PT)–60V2O5–30B2O3 with x = 0, 2.5, 5, 7.5 and 10 mol% were formed during heat treatment of conventional melt quenching glasses. X-ray diffraction was used to ensure glass and GCNs formation. Glasses and GCNs densities were measured by Archimedes principle. Fine polar clusters of lead titanate and/or barium titanate incorporation into vanadium borate glass matrix strongly depend on the composition. It was found out that the electrical conductivity of the initial glasses can be considerably improved by proper early stage of nanocrystallization at temperatures approaching the crystallization temperatures determined by DSC method. GCNs show massive increase in electrical conductivity (up to 6 orders of magnitude) as a function of BaTiO3 content. By increasing BaTiO3 content, the activation energy values have been found to increase. The enhancement in electrical conductivity of GCNs can be attributed to the increase in the crystalline phases in the glassy matrix which increases the concentrations of the V ion pairs. [ABSTRACT FROM AUTHOR]

Cadmium-doped borate glass composition was prepared via the melt-quenching technique. The nature of the glass structure was detected by X-ray diffraction (XRD). The physical parameters, such as density (ρ) from Archimedes' principle, molar volume (V m), C d 2 + ions concentration (N C d ), and inter-atomic distance (R i) were evaluated, providing structural information on glass samples. Fourier transform infrared (FT-IR) analysis was used to study the fundamental vibrational modes of structural units, confirming the conversion of B O 3 to B O 4 units, indicating a strongly bonded and high connectivity of the network. Some important optical findings were extracted from the analysis of optical absorption spectra. For example, the mitigation in the optical band gap, the increase in Urbach energy, the deterioration in the metallization criterion, and the enhancement in the electron-phonon interaction were obtained with cadmium oxide addition. The nonlinearity characteristics were enhanced, making these glass samples have viability in the non-linear optics sector. The obtained data from the electron spin resonance (ESR) revealed that the nickel ions exist in a divalent oxidation state with octahedral symmetry. Interestingly, the optical absorption transitions of N i 2 + ions were accurately deconvoluted and assigned to octahedral and tetrahedral positions. The equations of ligand field parameters of octahedral N i 2 + ions were correctly presented. The equation of Racah C parameter was deduced for the first time. Then, the ligand field parameters, such as the ligand field strength (10 Dq), Racah parameters (B and C), and other related parameters, were precisely assessed. The covalent nature between N i 2 + ions and the ligands was detected from the nephelauxetic effect. [ABSTRACT FROM AUTHOR]

Archimedes optimization algorithm (AOA) is a recent metaheuristic method inspired by the Archimedes principle, which is the law of physics. Like other metaheuristic methods, it suffers from the disadvantages of being stuck in local areas, suffering from weak exploitation abilities, and an inability to maintain a balance between exploration and exploitation. To overcome these weaknesses, a new hybrid Mutualism Archimedes Optimization Algorithm (MAOA) method has been proposed by combining the AOA and the mutation phase in the Symbiosis organism search (SOS) method. SOS algorithm is known for its exploitation ability. With the mutation phase, it has been used to improve local search for swarm agents, help prevent premature convergence and increase population diversity. To verify the applicability and performance of the proposed algorithm, extensive analysis of standard benchmark functions, CEC'17 test suites, and engineering design problems were performed. The proposed method is compared with the recently emerged and popular AOA, SOS, Harris Hawks Optimization (HHO), COOT Optimization Algorithm (COOT), Aquila Optimizer (AO), Salp Swarm Algorithm (SSA), and Multi-Verse Optimization (MVO) methods, and statistical analyses were performed. The results obtained from the experiments show that the proposed MAOA method has superior global search performance and faster convergence speed compared to AOA, SOS, and other recently emerged and popular metaheuristic methods. Furthermore, this study compares MAOA to five well-established and recent algorithms constructed using various metaheuristic methodologies utilizing nine benchmark datasets to assess the general competence of MAOA in feature selection. Therefore, the proposed method is considered to be a promising optimization method for real-world engineering design problems, global optimization problems, and feature selection. [ABSTRACT FROM AUTHOR]

The addition of titania to zirconia dental implants has been considered a promising choice to improve its bioactivity. This study aimed to evaluate the effect of different sintering conditions on the microstructure, density, optical properties and flexural strength of a 3Y-TZP/TiO 2 dental ceramic based on zirconia with two different titania contents (7.5 mol% and 12.5 mol%). 3Y-TZP/TiO 2 ceramic powders were synthesized by coprecipitation, uniaxially pressed and sintered at six different sintering conditions. Microstructural analysis of the sintered samples was performed by scanning electron microscopy and X-ray diffraction. Optical properties were measured using a spectrophotometer. The density was determined by Archimedes principle. Flexural strength was estimated by the biaxial flexure device. The microstructure and flexural strength of the 3Y-TZP/TiO 2 dental ceramic with 7.5% and 12.5 mol% were affected by the sintering conditions. Sintering the specimens at 1460 °C for 2 h increased the grain size and significantly decreased the flexural strength of 3Y-TZP/TiO 2 dental ceramic. The interaction (titania content x sintering conditions) affected the relative density and optical properties. A relative density greater than 98% was achieved for the T7.5 groups (sintered at 1260 °C/1 h, 1300 °C/1 h and 1300 °C/2 h) and for the T12.5 groups (sintered at 1260 °C/1 h, 1260 °C/4 h, 1300 °C/1 h and 1300 °C/2 h). The highest values of L*, a* and b* were respectively 87.2 (T7.5 group sintered at 1460 °C/2hs), 4.3 (T12.5 group sintered at 1300 °C/2hs) and 15.8 (T12.5 group sintered at 1300 °C/1 h). The material developed with 12.5 mol% of titania and sintered at 1300 °C/2 h showed high densification, flexural strength of 670 MPa and has good potential to be used in dentistry. [ABSTRACT FROM AUTHOR]

The paper considers the problems of estimation and provision of efficiency of rotary-screw propulsion units (RSP) for snow and swamp-going amphibious vehicles. The performance curves of fully submerged Archimedes screws of RSP are presented with parameters typical for snow and swamp-going amphibious vehicles. These parameters were obtained from the results of computer simulation. For a wide range of performance modes, the impact of particular elements of Archimedes screws on the general efficiency of the propulsion unit is analysed. According to the results of analysis of data received, lines of further research will aim to increase the efficiency of RSP when moving afloat. [ABSTRACT FROM AUTHOR]

Metal additive manufacturing technologies have great potential for future use in load-bearing aerospace applications, requiring a deeper understanding of mechanical performance and influencing factors. The objective of this study was to investigate the influence of contour scan variation on surface quality, tensile and fatigue strength for laser powder bed fusion samples made of AlSi7Mg0.6 material and to create high-quality as-built surfaces. The samples were produced with identical bulk and different contour scan parameters to accommodate the investigation of the impact of as-built surface texture on mechanical properties. The bulk quality was evaluated by density measurements according to Archimedes' principle and tensile testing. The surfaces were investigated using the optical fringe projection method, and surface quality was assessed by the areal surface texture parameters S a (arithmetic mean height) and S k (core height, derived from material ratio curve). Fatigue life was tested at different load levels, and the endurance limit was estimated based on a logarithmic-linear relation between number of cycles and stress. All samples were found to have a relative density of more than 99%. Surface conditions distinctive in S a and S k were successfully created. The resulting mean values of the ultimate tensile strength σ u l t are between 375 and 405 MPa for 7 different surface conditions. It was confirmed that the influence of contour scan variation on bulk quality is insignificant for the assessed samples. Regarding fatigue, one as-built condition was found to perform as well as surface post-processed parts and better than the as-cast material (compared to literature values). The fatigue strength at the endurance limit for 10 6 cycles is between 45 and 84 MPa for the three considered surface conditions. [ABSTRACT FROM AUTHOR]

Substoichiometric molybdenum oxide ceramics have aroused widespread interest owing to their promising optical and electrical performance. In this work, the thermal stability and decomposition mechanism of Mo9O26 and Mo4O11 at 700–1000 °C and 700–1100 °C were investigated, respectively. Based on this information, MoOx (2 < x < 3) bulk ceramics were prepared by spark plasma sintering (SPS). The results show that Mo9O26 is stable up to 790 °C in an argon atmosphere. As the temperature rises, it decomposes into Mo4O11. Mo4O11 can exist stably at 830 °C, beyond which it will convert to MoO2. The MoOx ceramic bulks with four different components (MoO2.9, MoO2.8, MoO2.7 and MoO2.6) were successfully sintered by SPS, and their relative density was greater than 96.4% as measured by the Archimedes principle. The reflectivity of MoOx ceramic bulk is low and only 6.3% when the composition is MoO2.8. The resistivity increases from 10−3 to 10−1 Ωcm with the increase in the O/Mo atomic ratio x. In general, the thermal stability information provides a theoretical basis for the processing of MoOx materials, such as the sintering of the MoOx target. The optical and electrical properties show that MoOx is a low-reflective conductive oxide material with great photoelectric application value. [ABSTRACT FROM AUTHOR]

The metal powder injection molding process is completed by mixing a metal powder and a binder, performing an injection molding and degreasing process, and then performing a sintering process for high density. The disadvantage of metal powder injection molding is that defects occurring during the process affect mechanical properties, which are worse in mechanical properties than in products manufactured by cold-rolling. In this study, the mechanical properties and microstructure of stainless steel 316L manufactured by the metal powder injection molding process were analyzed. Mechanical properties such as density, tensile strength, and fatigue life were analyzed. The density was measured using Archimedes' principle, and a relative density of 94.62% was achieved compared to the theoretical density. The tensile strength was approximately 539.42 MPa and the elongation to fracture was approximately 92%. The fatigue test was performed at 80% of maximum tensile strength and a stress ratio of R = 0.1. The fatigue life was found in 55% (297 MPa) of maximum tensile strength that achieved 106 cycles. The microstructure was observed through scanning electron microscope after etching, and as a result, the average grain size was 88.51 μm. Using electron backscatter diffraction, inverse pole figure map, image quality map, and kernel average misorientation map of the specimen were observed in three different areas which were undeformed, uniformly deformed, and deformed. Based on these results, it is expected that research is needed to apply the metal powder injection molding process to the manufacture of agricultural machinery parts with complex shapes. [ABSTRACT FROM AUTHOR]

The ever-increasing growth of the number of Internet of Things (IoT) devices connected to the network has led to the emergence of cloud computing shortcomings such as delay, storage and bandwidth. Fog computing has been developed as an emerging computing paradigm to overcome the challenges of cloud computing. This paradigm can support delay-critical and computationally intensive applications by providing resources at the network edge. As fog nodes appear with limited resources, IoT service placement schemes can improve the Quality of Service (QoS) and system performance. In general, the mapping between fog nodes and IoT services is known as the Service Placement Problem (SPP) in fog computing. To date, various meta -heuristic approaches have been introduced to solve SPP, but few are known in the research society due to computational complexity. Hence, this study proposes an efficient and autonomous scheme to solve SPP using meta -heuristic approaches with shared parallel architecture that can overcome the problem complexity. Specifically, we use the Archimedes Optimization Algorithm (AOA) as a new meta -heuristic approach inspired by the physics law of Archimedes' Principle. The proposed scheme, as SPP-AOA, formulates SPP as a multi-objective problem and performs the placement of autonomous services on distributed fog domains. Our main concerns in SPP are related to resource utilization, service cost, energy consumption, delay cost and throughput. SPP-AOA performs placement based on extracting resource distribution over time, which can save more resources to handle future requests. The effectiveness of the proposed scheme has been proven through evaluation on Barabasi-Albert network topology. Compared to the state-of-the-art methods, SPP-AOA deploys an average of 5% more service in fog, lowers costs by 2% and waiting time by 20%, and reduces placement on the cloud by 14%. [ABSTRACT FROM AUTHOR]

The glass samples with compositional range xLi 2 O-(40-x)B 2 O 3 -25ZnO-35 P 2 O 5 (LBZP) (where x = 5, 10, 15, 20, and 25) were prepared with the melt-quench method. The density, molar volumes of these glasses was estimated employing Archimedes's principle. The electrical properties of these glasses employing the impedance spectrometer have been investigated thoroughly at temperatures ranging from 333 K to 533 K and frequency windows between 20 Hz and 5 MHz. Several theoretical models such as Almond West formalism, correlated barrier hoping model, equivalent circuit models of Nyquist plots, etc., were used to estimate important parameters of the samples such as different conductivity and impedance parameters, the density of states, enthalpy parameters, etc. Dielectric studies of the samples were performed by analysing dielectric and modulus spectra. Bergman's model was used to analyse modulus spectra and Havriliak-Negami (HN) formalism was used to analyse dielectric spectra. Scaling formalism of modulus spectra was used to study the structure and temperature-dependent relaxation mechanism of the charge carriers. It has been shown that the samples with higher lithium content exhibit enhanced ionic and electronic conductivity. It indicates their possible application in electrode materials. • The study explores about lithium-borate-zinc-phosphate glasses. • Electrical property has been analyzed employing several theoretical models. • Increasing Li₂O content enhances both AC and DC conductivity. • Ions and polarons take part in charge conduction process. • LBZP glasses show promise as electrode materials in energy storage devices. [ABSTRACT FROM AUTHOR]

In this study, the dynamic structural and mechanical properties of the polymer composite with natural fiber reinforcement have been investigated experimentally and numerically. First of all, three different types, one-, three- and five-layered jute-epoxy and hemp-epoxy laminated composite, have been manufactured using the hand lay-up method. The tensile strength, bending strength and shear strength of the fabricated composite material have been investigated experimentally using Universal Testing Machine. The density is measured using a density measurement kit using Archimedes principle. Further, frequency and damping factors are also investigated using a vibration test setup. Later on, the numerical model is developed in finite element-based software ANSYS. Different natural frequency modes and corresponding damping factors have been investigated numerically. The mechanical and structural characteristics obtained experimentally and numerically are analyzed and discussed in detail. From the investigation, it is found that the hemp-epoxy composite has a greater strength and stiffness compared to the jute-epoxy composite, irrespective of the number of fiber layers used. Further, it is also found that with the increase in fiber layers or fiber percentage in the composite, the strength and stiffness of the fabricated composite increase significantly. [ABSTRACT FROM AUTHOR]

This work presents a didactic proposal aimed at high school students that aims to approach qualitatively and quantitatively the buoyant force. The objective of this proposal is to use a low-cost experiment, made with simple materials, to show and explore the existence and cause of the buoyancy, in addition to structuring a mathematical model for the calculation of such force. This experiment is also useful to reinforce and demonstrate concepts about hydrostatics such as pressure and Stevin's law, which are important for understanding and analyzing the buoyant force. This proposal is part of a project presented by the authors in the discipline Integrated Projects of Physics Teaching 1, of the licentiate degree course in Physics at the Federal University of Paraná. [ABSTRACT FROM AUTHOR]

A total of 320 pigs (Line 241 × 600, DNA, Columbus, NE; initially 11.9 ± 0.22 kg) were used in a 21-d growth study to determine the available P (aP) release curve for Smizyme TS G5 2,500 (Barentz, Woodbury, MN). At approximately 19 d of age, pigs were weaned, randomly allotted to pens, and fed common starter diets. Pigs were blocked by average pen body weight (BW) and randomly allotted to one of eight dietary treatments on day 18 postweaning, considered day 0 of the study. Dietary treatments were derived from a single basal diet and ingredients including phytase, monocalcium P, limestone, and sand were added to create the treatment diets. Treatments included three diets containing increasing inorganic P from monocalcium P (0.11%, 0.20%, and 0.28% aP), or five diets with increasing phytase (500, 1,000, 1,500, 2,000, or 2,500 FTU/kg) added to the diet containing 0.11% aP. All diets were corn–soybean meal–canola meal-based and were formulated to contain 1.24% standardized ileal digestibility Lys, 0.30% phytate P, and an analyzed Ca:P ratio of 1.10:1. Prior to the beginning of the study, all pigs were fed a diet containing 0.11% aP for a 2-d period (days 16 to 18 postweaning). At the conclusion of the study, one pig, closest to the mean weight of each pen, was euthanized and the right fibula, rib, and metacarpal were collected to determine bone ash, density, and total bone P. Bones were weighed while suspended in a vessel of water and the weights used to calculate bone density (Archimedes' principle). For bone ash, bones were processed using the non-defatted method. For the overall experimental period, pigs fed increasing inorganic P had increased (quadratic, P  ≤ 0.033) average daily gain (ADG), average daily feed intake (ADFI), and final BW and a tendency for increased (quadratic, P  ≤ 0.090) gain:feed ratio (G:F). Pigs fed increasing phytase had increased (quadratic, P  ≤ 0.004) ADG, G:F, and final BW and increased (linear, P  = 0.019) ADFI. For fibula, rib, and metacarpal characteristics, pigs fed increasing aP from inorganic P had increased (linear, P  < 0.001) bone ash weight, percentage bone ash, bone density, and bone P concentration. Additionally, pigs fed increasing phytase had increased (linear or quadratic, P  < 0.05) bone ash weight, percentage bone ash, bone density, and bone P. TheaP release curve generated for Smizyme TS G5 2,500 for percentage bone ash using data generated from all three bones is aP = (0.228 × FTU/kg) ÷ (998.065 + FTU/kg). [ABSTRACT FROM AUTHOR]

Additive-free nano-polycrystalline diamond (nPCD) composite was sintered by using a mixture of micro-diamond (MD) and onion-like carbon (OLC) as raw materials at 4–6 GPa/1000–1400 °C/5–30-min holding time. The composition, morphology, microstructure, density, and hardness of the nPCD composite were measured by XRD, FESEM, HRTEM, Archimedes principle, and Vickers hardness tester. Molecular dynamics of OLC with MD addition phase transition to nPCD at HPHT was calculated. The effect of MD and high-pressure sintering parameters on the OLC transformation process and the composition, microstructure, properties of nPCD composite were studied. The results showed that the MD was uniformly distributed in the nPCD composite. MD acted as the nucleus to promote the conversion of OLC to diamond. The increase in sintering pressure enhanced the density and hardness of the nPCD composite. When the sintering pressure was raised from 4 to 6 GPa, the density of the nPCD composite was increased from 2.72 to 3.02 g/cm3, and the hardness was increased from 41.85 to 56 GPa. The increase in sintering temperature and holding time made the density and hardness of the nPCD composite increase first and then decrease. Nanotwinned diamond with 10-nm size appeared in the nPCD region in the nPCD composite. The presence of nanotwinned diamonds increased the hardness of the nPCD composite. [ABSTRACT FROM AUTHOR]

Stoichiometric tin diselenide (SnSe2) platelet crystals have been prepared by physical vapor deposition (PVD) method under high vacuum (~ 10–6 mbar) using a homemade dual-zone furnace. The driving force for growth was optimized in terms of temperature difference (ΔT = 270 to 420 °C) of nutrient and growth zones. Good quality platelets, devoid of any screw dislocations, hillocks, defects etc. were crystallized at ΔT = 400 °C by layer growth mode as per the 3D optical profiler and electron microscopic images. Rietveld refinement of the PXRD data using FullProf suite software justified hexagonal crystal structure with a = 3.811 Å, c = 6.137 Å and the computed density (5.967 g/cm3) is in agreement with that obtained based on Archimedes principle. Chemical homogeneity of these samples was probed by EDAX, XPS and Raman analysis. The thermal and mechanical behavior was investigated by TGA as well as Vickers microhardness experiments. The values of optical band gap (1.20 eV), absorption coefficient (7.25 × 105 cm−1), resistivity (2.70 Ω cm), mobility (32.70 cm2V−1 s−1) and carrier concentration (3.08 × 1016 cm−3) have been evaluated using UV–Vis-NIR, photoluminescence, and Hall effect measurements. The enhancement of optoelectronic parameters of the as-grown SnSe2 platelets free of polytypism, throws light on their potential for photovoltaic applications. [ABSTRACT FROM AUTHOR]

This research aims to compact pure aluminum (Al) powder in a radial direction using the electromagnetic forming method. The pure Al powder was placed inside the Al tube and closed rigidly with end plugs. The Al tube used here acts as a force-transmitting medium to compact the powder using Lorentz forces and hold the powder intact. In this process, electromagnetic Lorentz forces were utilized to consolidate the powder. A copper solenoid coil with the help of a field shaper is used to generate the Lorentz forces. These forces were obtained when a high magnitude electrical current passes through the solenoid coil and its induced effect current in the adjacent tube. The radially acting magnetic field pressure deforms the Al tube; subsequently, the Al powder gets consolidated inside the tube. Thereby, a highly denser Al compact is obtained through a new technique. In this study, the effect of compaction voltage on various mechanical properties of the compact was studied. After successfully consolidating Al powder in the Al tube, the microstructures of the compacted samples were analyzed to characterize the porosity and distribution of powder particles using a scanning electron microscope and optical microscope results. The final diameter of the compressed samples was measured at several locations using Vernier callipers. Archimedes principle was used to determine the densities of the consolidated powder sample to ascertain the sintered density of the samples at various energies. Hardness tests were conducted on normal cross sections using Brinell hardness and Vickers hardness tester. [ABSTRACT FROM AUTHOR]

This study aims to analyze Kolb's Learning Style (KLS) in solving HOTS questions for prospective physics teacher students. This research is a descriptive study using a qualitative approach. The subjects of this research are second semester students who have joined the Basic Physics course for Archimedes' Principle, amounting to 46 people. The instrument used was a Kolb's Learning Style (KLS) questionnaire, which consisted of 40 statement items, 8 essay questions about HOTS, and interview guidelines. Based on the results of the study, it showed that from the maximum percentage (100%) in each Kolb's Learning Style (KLS) obtained the combination of diverger and assimilator learning styles as the highest average percentage (65.63%) in solving HOTS questions correctly compared to the other learning styles. It is followed by the accomodator (56.25%), the combination of assimilator and converger (54.17%), diverger (53.41%), assimilator (49.22%), and converger (48.61%). There are differences in Kolb's Learning Style (KLS) in solving HOTS questions for prospective physics teacher students where students still experience errors in answering questions. The forms of incorrect answers given by students include: 1) Objects with a smaller surface area must be sink, 2) Heavy objects must be sink, 3) The amount of water affects the state of floating and sinking, 4) Hollow objects always float, and 5) Objects made of something hard must be sink. Based on the results of this study, it can be concluded that the ability of prospective physics teacher students in solving HOTS questions must be trained by adjusting their learning styles.

Densities for various Tetramethylammonium hydroxide (TMAH) solutions at different temperatures have been determined based on Archimedes’ principle using a hydrostatic balance and a vitreous body with a defined volume. Due to the toxicity of the compound, these data are important especially in the field of wet processing techniques for the automated dosage of TMAH.

Simple Summary: The ability to obtain in vivo information on characteristics related to fish composition is necessary for aquaculture. In addition, there is growing interest in production traits, such as growth, feed efficiency or fillet weight, but it remains difficult to precisely record in vivo individual fish traits that report to these production traits, which can increase edible fish meat production and decrease the environmental impact. In the present study, we performed an ultrasound approach for the in vivo prediction of fillet volume of the Senegalese sole (Solea senegalensis), a species considered a promising flatfish species for marine fish farming. The results show that models based on ultrasound fillet volume measurements explain above 95% of the variation observed in fillet volume. However, for fillet yield estimation, the results were modest. Therefore, further studies are necessary to better understand the potential of the ultrasound approach to this trait. Nevertheless, this work allows us to conclude that the approach with ultrasound is promising for measuring in vivo fish composition traits. Senegalese sole (Solea senegalensis) has been considered a promising new flatfish species for Mediterranean marine fish farming. Accurate prediction of fillet traits in live animals may allow for more efficient control of muscle deposition in fish. In this sense, this study was undertaken to develop a non-invasive method to predict in vivo fish fillet volume and yield using real-time ultrasonography (RTU). The trial was conducted with 44 market weight Senegalese sole (298.54 ± 87.30 g). Fish were scanned with an Aloka SSD 500V with a 7.5 MHz probe. Ten RTU cross-sectional images were taken from the operculum to the caudal fin at regular intervals. These images were analyzed using Fiji software. These data were then used to estimate the partial volumes of the fillet. Actual fillet volume was determined using Archimedes' principle. Simple and stepwise multiple regression analyses were then used to develop prediction models of fillet volume and yield. The most cranial RTU sections of the fish fillet were the best single predictors of both fillet volume and fillet yield and were the ones included in the best stepwise models. The best RTU slice area explained 82% of the variation observed in fillet volume, but the other RTU slice areas used as predictors of fillet volume showed poor to moderate accuracy (0.035 ≤ R2 ≤ 0.615). Single RTU partial volumes showed poor to very high accuracy (0.395 ≤ R2 ≤ 0.970) as predictors of fillet volume. The best stepwise model based on the RTU slice areas included three independent variables and explained 88.3% of the observed variation. The best stepwise models based on RTU partial volumes (single volumes and/or combinations of single volumes) explained about 97% of the variation observed in fillet volume. Two RTU volume traits, V1–5 + V6–9, and V1+()+9, showed to be practically direct predictors of the actual fillet volume, explaining, respectively, 97% and 96% of the variation observed in the actual fillet volume. The fillet yields show lower correlations with slice areas (r between 0.044 and 0.601) than with volumes (r between 0.288 and 0.637). While further studies are clearly necessary to better understand the potential of RTU for the estimation of fillet yield in fish in general and Senegalese sole in particular, the present results showed that RTU traits can be very good predictors of Senegalese sole's fillet volume, either used in regression models or as direct predictors. [ABSTRACT FROM AUTHOR]

Foams glass were obtained from solid waste of flat glass and exhausted alkaline batteries. The physical, chemical, crystalline and morphological properties of the samples were obtained using the Archimedes principle, X-ray diffractometry (XRD), scanning electron microscopy (SEM). The results revealed glass foams with apparent porosities in the range of 55–64% and apparent densities in the range of 0.40–0.79 g cm−3. The manganese oxide and graphite contained within the cathode of alkaline batteries acted as both oxidizing agents and as foaming agents. The zinc contained in the anode acted as a pore stabilizing agent and the zinc oxide as a semiconductor material. The foam glass that was composed of flat glass with an anode of Zn and ZnO, and a cathode of Mn 2 O 3 and Mn 3 O 4 (named An8), showed the greatest potential for heterogeneous photocatalysis, with a maximum efficiency of 95.9% after 3 h of treatment of solution containing dye. These results suggest the feasibility of producing foam glass from waste, as well as its potential application in photocatalytic systems, such as in the low-cost treatment of water. [ABSTRACT FROM AUTHOR]

The study presents the corrosion behaviour and wear response of pulsed electric current sintered binderless TiC 50 N 50 , TiC 70 N 30 , and TiC 90 N 10 based ceramic composites, consolidated by spark plasma sintering (SPS), and the relative densities were evaluated using the Archimedes principle. The microstructural evolutions of the sintered samples were examined through various microscopy techniques, and their susceptibility to corrosion in aggressive chloride environment was assessed using open circuit potential, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods. The microstructural examination of the specimens showed the presence of different phases within the titanium carbonitride (TiCN) cermets. The wear resistance evaluated using the frictional coefficient (COF) and calculated wear rate showed that the specimens exhibited an improved resistance. The specimens further showed enhanced resistance to corrosion in the test electrolyte, as the TiC 50 N 50 cermet displayed enhanced resistance to the aggressive chloride ions in comparison to the other specimens. [ABSTRACT FROM AUTHOR]

Dielectric properties of a magnesium silicate (MgSiO3) linear low-density polyethylene nanocomposite are studied in the X-band frequencies to realize its application as a substrate for high-frequency devices. MgSiO3 ceramics are synthesized by conventional solid state technique. Structural and morphological characteristics of MgSiO3 nanoparticles are confirmed by X-ray diffraction, Fourier transform infrared spectroscopy and transmission electron microscopy. Transmission electron microscopy images reveal the average particle size to be ~100 nm. Composites are prepared by uniform dispersion of the nano-inclusions MgSiO3 in a linear low-density polyethylene matrix in three different wt.%, viz. 2%, 4% and 6%. The fractured lateral side of the composite is examined under a scanning electron microscope to ensure the uniform dispersion of the inclusions in the polymer. Water absorption measurement is carried out based on ASTM D570-98. Densities of the samples are measured by hydrostatic weighing by using Archimedes principle. Thermal conductivity of the composites is measured by modified hot plat method. Nicholson-Ross approach is used to investigate the dielectric characteristics of composites. The permittivity and dielectric loss tangent of the nano-composite in the X-band are found to be ~2.2–2.5 and 10−2–10−4 for all the inclusion concentration respectively. To see the applicability of the nanocomposite in the field of antenna, return losses are calculated from complex permittivity and complex permittivity data. [ABSTRACT FROM AUTHOR]

The titica vine fiber (TVF) (Heteropsis flexuosa) is a natural lignocellulose fiber (NLF) from the Amazon rainforest that was, for the first time, investigated in terms of its basic properties such as dimensions, porosity, and density as well as its chemical composition, moisture content, crystallinity, and microfibrillar angle. In this study, the apparent density of TVF was determined as one of the lowest-ever reported for NLFs). Using both the geometric method and Archimedes' principle, density values in the range of 0.5–0.6 g/cm3 were obtained. The moisture content was measured as around 11%, which is in accordance with the commonly reported values for NLFs. The TVF exhibited a high porosity, approximately 70%, which was confirmed by SEM images, where a highly porous morphological structure associated with the presence of many voids and lumens was observed. The crystallinity index and microfibrillar angle were determined as 78% and 7.95°, respectively, which are of interest for a stiff NLF. A preliminary assessment on the mechanical properties of the TVFs revealed a tensile strength, Young's modulus, and elongation of 26 MPa, 1 GPa, and 7.4%, respectively. Furthermore, the fiber presented a critical length of 7.62 mm in epoxy matrix and an interfacial shear strength of 0.97 MPa. These results suggest the TVFs might favors applications where lighter materials with intermediate properties are required. [ABSTRACT FROM AUTHOR]

The article discusses research which focused on the room temperature (RT) aging of ultrastable metallic glasses (MG). Topics explored include the thermodynamic and kinetic stability of various glass materials, the use of X-ray diffraction to examine the phase structure of aged MG at RT, and the crystallization resistance observed in MG after being annealed at various temperatures.

Titanium metal matrix composites/TMMCs are reinforced ceramic reinforcements that have been developed and used in the automotive, biological, implants, and aerospace fields. At high temperatures, TMMCs can provide up to 50% weight reduction compared to monolithic super alloys while maintaining comparable quality or state of strength. The objective of this research was the analysis and evaluation of the effect/influence of different sintering temperatures, reinforcement size dependence of mechanical properties, and fortification mechanisms on the particle size distribution of B4C, SiC, and ZrO2 reinforced TMMCs that were produced and fabricated by powder metallurgy/PM. SEM, XRD, a Rockwell hardness tester, and the Archimedes principle were used in this analysis. The composites' hardness, approximation, tensile, yielding, and ultimate strength were all increased. As the composite was reinforced with low-density ceramics material and particles, its density decreased. The volume and void content in all the synthesized specimens is below 1%; this is the result of good sample densification, mechanical properties and uniform distribution of the reinforced particle samples; 5% B4C, 12.5% SiC, 7.5% ZrO2, 75% Ti develop higher mechanical properties, such as higher hardness, approximation tensile, yielding, and ultimate strength and low porosity. [ABSTRACT FROM AUTHOR]

Metallic material concepts associated with the sustainable and efficient use of resources are currently the subject of intensive research. Al addition to steel offers advantages in view of lightweight, durability, and efficient use of high-Fe scrap from the Al industry. In the present work, Al was added to Fe-12Cr-(9,12)Ni-3Mn-0.3C-xAl (x = 0.1–6) (wt.%) stainless steels to assess its influence on microstructure and mechanical properties. According to density measurements based on Archimedes' principle, densities were between 7.70 and 7.08 g/cm3. High-energy X-ray diffraction estimations of the lattice parameter indicated that nearly 31% of density reduction was caused by the lattice expansion associated with Al addition. Depending on Al concentration, austenitic and duplex matrix microstructures were obtained at room temperature. In the presence of up to 3 wt.% Al, the microstructure remained austenitic. At the same time, strength and hardness were slightly enhanced. Al addition in higher quantities resulted in the formation of duplex matrix microstructures with enhanced yield strength but reduced ductility compared to the austenitic alloys. Due to the ready formation of B2-(Ni,Fe)Al intermetallics in the ferrite phase of the present alloy system, the increase in strength due to the presence of ferrite was more pronounced compared to standard duplex stainless steels. The occurrence of B2 intermetallics was implied by dilatometry measurements and confirmed by electron microscopy examinations and high-energy X-ray diffraction measurements. [ABSTRACT FROM AUTHOR]