Search

Highlights PEEK and CF/PEEK are two significant materials whose properties are intricately linked to their crystallization behavior. This study employed three analytical techniques—density method, differential scanning calorimetry (DSC), and x‐ray diffraction (XRD)—to explore and quantify the crystallinity of Poly (ether ether ketone) (PEEK) and its composites. Thermogravimetric analysis was used to determine the resin content of the composites, which is essential for the density and DSC methods. The density method, based on Archimedes' principle, calculated both mass and volume crystallinity. DSC assessed crystallinity by analyzing differences in melting enthalpy, while XRD determined crystallinity through diffraction patterns and peak analysis. The results demonstrate that these three techniques can be effectively utilized for calculating the crystallinity of PEEK and its composites. Using the density method, PEEK exhibited a crystallinity of (26.53 ± 1.30)% by mass and (24.57 ± 1.24)% by volume. The prepreg, CF/PEEK, and CF/PEEK‐AA1 composites showed enhanced crystallinity values. Crystallinity calculated by DSC was 29.16% for PEEK, 55.35% for prepreg, 55.48% for CF/PEEK, and 53.50% for CF/PEEK‐AA1. XRD results provided crystallinity values of 46.35% for PEEK, 63.20% for prepreg, 64.80% for CF/PEEK, and 66.57% for CF/PEEK‐AA1, along with detailed information about unit cells and crystal planes. This study contributes to a better understanding of these methods, paving the way for future refinement and integration, thereby improving the precision of crystallinity determination.Crystallinity study of PEEK and CF/PEEK composites by density, DSC and XRD methods. Crystallinity calculated by methods in different principles are irrelevant. Crystallinity estimated by density and DSC requires resin content. Information on crystal and crystallinity can be obtained by XRD independently. Crystallinity calculated by XRD is the highest. Results obtained by density and DSC method are close. [ABSTRACT FROM AUTHOR]

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]

In the present study, TiXMo5Cu alloys were produced utilizing the powder metallurgy technique. Alloy samples with different ratios of Mo added were shaped by uniaxial pressing under 550 MPa pressure. The shaped samples were subjected to a sintering process at 5 different temperatures for a waiting time of 180 min in a 99.99% pure argon gas atmosphere. The densities of the fabricated specimens were found with the Archimedes principle. Microstructures of the obtained samples were attained by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) examinations. For the determination of the mechanical characteristics, micro hardness and tensile tests were applied. According to the density measurements, the highest relative density values were attained with the sintering temperature of 1300 °C, and a higher Mo ratio resulted in a lower relative density. The microstructure of the fabricated specimens is comprised of α-Ti and β-Ti phases. The α-Ti phase ratio in the microstructure reduced based on rising Mo, while the ratio of the β-Ti phase increased. Accordingly, while the hardness values increased, the strength values decreased. [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.

Purpose: Material extrusion (ME) is a low-cost additive manufacturing (AM) technique that is capable of producing metallic components using desktop 3D printers through a three-step printing, debinding and sintering process to obtain fully dense metallic parts. However, research on ME AM, specifically fused filament fabrication (FFF) of 316L SS, has mainly focused on improving densification and mechanical properties during the post-printing stage; sintering parameters. Therefore, this study aims to investigate the effect of varying processing parameters during the initial printing stage, specifically nozzle temperatures, Tn (190°C–300°C) on the relative density, porosity, microstructures and microhardness of FFF 3D printed 316L SS. Design/methodology/approach: Cube samples (25 x 25 x 25 mm) are printed via a low-cost Artillery Sidewinder X1 3D printer using a 316L SS filament comprising of metal-polymer binder mix by varying nozzle temperatures from 190 to 300°C. All samples are subjected to thermal debinding and sintering processes. The relative density of the sintered parts is determined based on the Archimedes Principle. Microscopy and analytical methods are conducted to evaluate the microstructures and phase compositions. Vickers microhardness (HV) measurements are used to assess the mechanical property. Finally, the correlation between relative density, microstructures and hardness is also reported. Findings: The results from this study suggest a suitable temperature range of 195°C–205°C for the successful printing of 316L SS green parts with high dimensional accuracy. On the other hand, Tn = 200°C yields the highest relative density (97.6%) and highest hardness (292HV) in the sintered part, owing to the lowest porosity content (<3%) and the combination of the finest average grain size (∼47 µm) and the presence of Cr23C6 precipitates. However, increasing Tn = 205°C results in increased porosity percentage and grain coarsening, thereby reducing the HV values. Overall, these outcomes suggest that the microstructures and properties of sintered 316L SS parts fabricated by FFF AM could be significantly influenced even by adjusting the processing parameters during the initial printing stage only. Originality/value: This paper addresses the gap by investigating the impact of initial FFF 3D printing parameters, particularly nozzle temperature, on the microstructures and physical characteristics of sintered FFF 316L SS parts. This study provides an understanding of the correlation between nozzle temperature and various factors such as dimensional integrity, densification level, microstructure and hardness of the fabricated parts. [ABSTRACT FROM AUTHOR]

Egg -related research promises unique opportunities for food science and technology. There is an urgent need to develop non-destructive methodologies for defining key egg parameters, e.g., egg volume (V) and surface area (S), based only on egg images. Herewith, V can be measured using the Archimedes' principle (i.e., dipping in water), while S can be inferred using formulae that include V as one of its variables. Although the Archimedes' principle is the best approach for determining K dipping an egg into water cannot be practicable. In this study, we derived the appropriate mathematical approaches to calculate Vand S based on measurements of quail eggs linear parameters. The proposed calculation formulae are suitable for eggs of any shape and species. This innovative procedure can be employed as the basis of the most accurate of all existing methods for computing S and is suitable for both analytical and industrial measurements of V. [ABSTRACT FROM AUTHOR]

We explore the stability of floating objects at a two-fluid interface through mathematical modeling and experimentation. Our models are based on standard ideas of center of gravity, center of buoyancy, and Archimedes' Principle extended to the two-fluid scenario. We investigate floating shapes with uniform, two-dimensional cross sections and identify analytically and/or computationally a potential energy landscape that helps identify stable and unstable floating orientations. We compare our analyses and computations to experiments on floating objects designed and created through 3D printing. Additionally, the paper includes open problems for further study. [ABSTRACT FROM AUTHOR]

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]

In the present study, we have prepared six glass samples of bismuth borate using the melt-quenching method with the composition (70-x)B2O3-10CaO-20Na2O-xBi2O3; x  = 0, 3, 6, 9, 12 and 15 mol%. The density of the prepared glasses was determined using Archimedes principle. The X-ray diffraction patterns provide confirmation of the amorphous nature of the prepared samples, whereas the Fourier transform infrared measurements pointed to the existence of structural units like BO3, BO4, BiO3 and BiO6 within the glass network. An assessment of the optical absorption spectra unveiled that with the increase in the bismuth oxide content, there was a decrease observed in both the direct and indirect band gap energies. Specifically, they decreased from 3.40 to 2.79 eV and from 3.10 to 2.46 eV, respectively. The properties related to gamma ray attenuation, including the mass attenuation coefficient (μ m), effective atomic number (Z eff), half-value layer (HVL) and mean free path (MFP), were examined for all the glass samples. This investigation was carried out using the Phy-X/PSD software, covering the energy range from 0.511 to 1.332 MeV. Out of all the samples, Bi-15, featuring the highest Bi2O3 content, demonstrated the highest μ m, Z eff, the smallest HVL and MFP. These results suggest that the glass with 15 mol% of Bi2O3 offers the most effective gamma radiation shielding performance. Moreover, the glasses examined in this study exhibit superior radiation shielding characteristics compared with specific concrete types, namely, ordinary concrete, Hematite serpentine concrete and barite concrete, as well as commercial glasses such as RS-360 and RS-253. [ABSTRACT FROM AUTHOR]

A combined experimental and numerical research study is conducted to investigate the complex relationship between the structure and the aerodynamic performances of an Archimedes spiral wind turbine (ASWT). Two ASWTs are considered, a prototypical version and an improved version. It is shown that the latter achieves the best aerodynamic performance when the spread angles at the three sets of blades are α1 = 30°, α2 = 55°, α3 = 60°, respectively and the blade thickness is 4 mm. For a velocity V = 10 m/s, a tip speed ratio (TSR) = 1.58 and 2, the maximum CP values are 0.223 and 0.263 for the prototypical ASWT and improved ASWT, respectively, and the maximum CP enhancement is 17.93%. For V = 10 m/s and TSR = 2, the CP values of the prototypical ASWT and improved ASWT are 0.225 and 0.263, respectively, with an aerodynamic performance enhancement of 16.88%. Through mutual verification of the test outcomes and numerical results, it is concluded that the proposed approach can effectively lead to aerodynamic performance improvement. [ABSTRACT FROM AUTHOR]

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]

Archimedes Optimization Algorithm (AOA) is a recent optimization algorithm inspired by Archimedes' Principle. In this study, a Modified Archimedes Optimization Algorithm (MDAOA) is proposed. The goal of the modification is to avoid early convergence and improve balance between exploration and exploitation. Modification is implemented by a two phase mechanism: optimizing the candidate positions of objects using the dimension learning-based (DL) strategy and recalculating predetermined five parameters used in the original AOA. DL strategy along with problem specific parameters lead to improvements in the balance between exploration and exploitation. The performance of the proposed MDAOA algorithm is tested on 13 standard benchmark functions, 29 CEC 2017 benchmark functions, optimal placement of electric vehicle charging stations (EVCSs) on the IEEE-33 distribution system, and five real-life engineering problems. In addition, results of the proposed modified algorithm are compared with modern and competitive algorithms such as Honey Badger Algorithm, Sine Cosine Algorithm, Butterfly Optimization Algorithm, Particle Swarm Optimization Butterfly Optimization Algorithm, Golden Jackal Optimization, Whale Optimization Algorithm, Ant Lion Optimizer, Salp Swarm Algorithm, and Atomic Orbital Search. Experimental results suggest that MDAOA outperforms other algorithms in the majority of the cases with consistently low standard deviation values. MDAOA returned best results in all of 13 standard benchmarks, 26 of 29 CEC 2017 benchmarks (89.65%), optimal placement of EVCSs problem and all of five real-life engineering problems. Overall success rate is 45 out of 48 problems (93.75%). Results are statistically analyzed by Friedman test with Wilcoxon rank-sum as post hoc test for pairwise comparisons. [ABSTRACT FROM AUTHOR]

In this study, epoxy matrix composites containing mica with different particle sizes (40 and 80 µm) and quantities (0, 10, 20, 40 wt.%) were produced by the casting method. Composites were coated with a commercial agent imparting hydrophobicity in order to decrease water absorption. The bulk density and % open porosity values of the finished composites were determined by Archimedes' principle, and detailed microstructural analysis was carried out with scanning electron microscopy (SEM). The surfaces were characterized by the contact angle and roughness measurements. The durability and protective performance of the coating were quantified by the water absorption tests for various immersion times and temperatures (ASTM D570-98) and salt water resistance tests. Microstructure analysis showed that for all filler ratios and particle sizes, mica particles were homogeneously dispersed in the epoxy matrix and the mica–polymer interface was well bonded. It has been observed that the % theoretical density values of the composite products vary between 91.1 and 98.6%, and the total porosity varies between 1.4 and 8.87%. As the amount of mica increased, the total porosity also increased, regardless of the size of the mica particles. The neat epoxy matrix absorbed a higher quantity of water than composites in almost all cases, and the water absorption of the composites decreased with the increasing mica quantities and the decreasing particle size. The hydrophobic coating definitely caused the water absorption rates of the composite samples to decrease and the salt water resistance to increase, rendering them a convenient moisture- and corrosion-resistant composite material. [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.

The article discusses common student misconceptions about volume and capacity, emphasizing the need for a deeper understanding of these concepts. It highlights the importance of hands-on activities to develop conceptual understanding and differentiate between volume and capacity. The text also delves into the historical context of volume measurement units and the significance of understanding units in measurement. Practical examples and activities are provided to enhance learning and address misconceptions effectively. [Extracted from the article]

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]

Stereology is a discipline that allows us to obtain quantitative information about the geometric structure of three‐dimensional objects. In this study, the volume of grey matter (GM), white matter (WM), and lateral ventricle (LV) of the cerebral hemispheres (CH) in sheep and goats were calculated. For this purpose, six healthy male sheep and goat brains (1–2 years old) without any anomaly were used. Brains were fixed with 10% formaldehyde in the skull. The skull was opened using standard anatomical dissection methods, and the brains were carefully removed. Brain weight and volume were measured (using Archimedes' principle) after the meninges were removed. The cerebral hemispheres were separated from the other parts of the brain by a section made in front of the rostral colliculus. In the same way, the weight and volume of the cerebral hemispheres were measured. Afterward, the cerebral hemispheres were blocked with agar, and transversal cross sections (from rostral to caudal) with an average thickness of 3.42 mm were taken from the cerebral hemispheres. Grey matter was stained with Berlin blue macroscopic staining method. The stained cross sections were scanned at 600 dpi resolution, and a point counting grid was placed on the images with the ImageJ software. Cavalieri's principle calculated the surface area and volume measurements of the grey matter, white matter, and lateral ventricle. GM, WM, and LV volumes in sheep and goat cerebral hemispheres were calculated as 54.94, 21.48 and 3.06 mL in sheep, 57.46, 24.13 and 3.12 mL in goats, respectively. The percentages of these structures in the total hemisphere volume were 71.83%, 28.17% and 4.00% in sheep, 70.42%, 29.58% and 3.82% in goats, respectively. Asymmetry was not observed in cerebral hemispheres in both species. A difference was found in the WM, LV and LV: CH ratios in the right/left comparison of the goat (p < 0.05). In comparing sheep and goats, a significant difference was observed in WM right, WM left, WM total, CH left and CH total (p < 0.05). In conclusion, the cerebral hemispheres' grey matter and white matter ratio are frequently used to diagnose neurodegenerative diseases. In recent years, the increase in neurodegenerative disease models in farm animals has been enormous. It is thought that these values obtained from healthy animals in the current study will be important for such experimental studies in the future. [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]

Titanium and its alloys are used to make dental implants because of its low density, high strength, and corrosion resistance. This paper describes the development of a potential biomaterial Ti‐10Nb by powder metallurgy utilizing four different compaction pressures and analyses its microstructural, physical, mechanical, electrochemical, biological, and tribological behavior under various situations. The alloys were fabricated using four different compaction pressures, that is, 600, 650, 700, and 750 MPa, and sintered in a vacuum atmosphere at 1000°C for 1.5 h. The density of the samples was measured using Archimedes principle. X‐ray diffraction and scanning electron microscopy equipped with energy dispersive spectroscopy were used to investigate the phase composition and microstructure, and a profilometer was used to examine the surface roughness of various samples. Vickers hardness tester was used to evaluate hardness, and a universal testing machine was used for compression testing. Corrosion and wear behavior were examined using a potentiostat and a Bio‐Tribometer, respectively. This Ti‐10Nb alloys consist of α + β phase, and have 16% highest porosity in sample compacted at 600 MPa. The samples compacted at 750 MPa achieved highest hardness, yield strength, compressive strength, and elastic modulus of 450 ± 29.72 HV, 718.22 ± 16.37 MPa, 1543.59 ± 24.37 MPa, and 41.27 ± 3.29 GPa, respectively. In addition, it also possesses highest corrosion and wear resistance with lowest icorr of 0.3954 ± 0.008 μA/cm2 and wear volume of (31.25 ± 0.206) × 10−3 mm3. These results indicate that the developed alloys have a variety of desirable properties, including high hardness, adequate compressive strength, good corrosion and wear resistance, apatite‐forming capability, and a low elastic modulus, which is advantageous for avoiding stress shielding. Therefore, it may be recommended to use it as a dental implant material. [ABSTRACT FROM AUTHOR]

In contemporary transportation and automotive industries, the demand for materials featuring optimal physical and mechanical properties coupled with reduced weight is paramount. This study investigates the influence of alumina reinforcement, utilizing powders of varying particle sizes, on the properties of Al-Cu-Mg composite materials. Specifically, the effects of incorporating alumina powder with a particle size of 56μm and 20nm, each at a volume ratio of 1%, into Al-Cu-Mg composite alloys were examined. The density of the composites was assessed employing the Archimedes principle, while their porosity and microhardness were also evaluated. Additionally, the composites underwent SEM characterization, quantitative analysis, and EDS mapping. The findings reveal that the composite reinforced with nano-sized Aluminum Oxide (Al2O3) demonstrated superior performance, manifesting a relative density of 55.61%, the lowest porosity at 5.47%, and the highest microhardness value of 55.7HV. These enhanced characteristics are corroborated by the results of the SEM-EDS microstructural observations. The employment of nano-Al2O3 in the Al-Cu-Mg composite alloy significantly optimizes its physical and mechanical attributes, rendering it an advantageous material for the fabrication of lighter and more robust components in transportation and automotive applications. The study's outcomes underscore the critical role of particle size in the reinforcement of aluminum matrix composites, highlighting the potential of nano-reinforcements in advancing material properties for industryspecific applications. [ABSTRACT FROM AUTHOR]

As a supplemental technique for disease diagnosis, expelled breath monitoring is becoming extremely prevalent. Nevertheless, because of the significant number of factors that must be considered, researchers are forced to create new algorithms for accurate data interpretations. In our study, a novel noninvasive breath biomarkers-based diabetic detection strategy is introduced by upcoming three main processes "pre-processing, feature extraction and diabetes detection". Raw data (breath signal) are initially pre-processed via data normalization to increase acquired breath signal quality. Most important features, such as "Improved empirical wavelet functions (IEWF), empirical mode decomposition (EMD), local mean decomposition (LMD), continuous wavelet transform (CWT) method, and entropy-based feature," are extracted from the pre-processed data. These attributes are fused together and are subsequently used to train the ensemble of classifiers in the diabetes detection stage. An ensemble of classifiers, including an "optimized quantum deep neural network (QDNN), a convolutional neural network (CNN), and a recurrent neural network (RNN)", is used to depict the diabetes detection phase. The CNN and RNN are trained using the retrieved fused features. The optimized QDNN receives the output of the CNN and RNN. The final detected result is provided by the optimized QDNN. A unique hybrid optimization model, Archimedes Principle with Enhanced Honey Badger Exploitation (APEHBE) algorithm, that combines the Archimedes Optimization Algorithm (ArchOA) and the Honey Badger Algorithm (HBA) is used to fine-tune the weight of QDNN. The effectiveness of the anticipated model is then verified by a comparison analysis. [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]

This article discusses a study published in Antarctic Science that examines the effects of repeated freezing on the buoyancy and photosynthesis of southern bull kelp, a species known to raft to Antarctica. The researchers found that freezing and thawing events led to decreased buoyancy and photosynthetic efficiency in the kelp samples. These findings suggest that freezing can have significant impacts on the health and success of non-native species in the Antarctic. The study highlights the importance of further research to understand the effects of freezing on kelp's reproductive viability and long-term survival and growth. Overall, this research has implications for the potential establishment of non-native species on Antarctic coastlines. [Extracted from the article]

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]

The article in the Physics Teacher journal discusses a novel method of using a smartphone's pressure sensor to measure the density of a solid object. By comparing pressure values when the object is in air and fully immersed in a nonreactive liquid, the density of the object can be determined. The experiment involves placing the object on a ziplock bag and recording pressure readings, leading to a calculated density value. The study demonstrates the potential of smartphone technology for scientific measurements and practical demonstrations of physics principles. [Extracted from the article]

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]

Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

One of these lab books from 1907 was recently discovered and has been republished in French under the title I Leçons de Marie Curie. i [11] Kept by the young student Isabelle Chavannes, it contains a step-by-step record of 10 physics lessons on such topics as pressure, mass, density, and the Archimedes principle. Colleague Dr. Jean Perrin described Curie as "the greatest lab director I have ever known."[14] Lab worker Moise Haissinsky, wrote, She was able to direct the huge institute and its numerous physical and chemical laboratories, aware of all that was going on in them, mindful of every detail of the work we were involved in. Many people extol Marie Sklodowska Curie as a two-time Nobel Prize winner. One of Curie's students, Hélène Emmanuel-Zavizziano, from Greece, said that "la patronne" (Dr. Curie) would stop by every two or three days to discuss the progress of her experiments. [Extracted from the article]

The melt-quenching approach was implemented to create terbium-doped lithium sodium potassium borate glasses (LNKBTb). Archimedes' principle, absorption and luminescence spectra, including CIE chromaticity were used to characterize the properties of glasses. Terbium in glasses absorbs photon in the visible and near infrared ranges. The intense green emission at 544 nm was generated by the terbium 5D4 to 7F5 transition when excited with ultraviolet–visible (UV–Vis) light. The emission intensities of LNKBTb glasses increased with increasing terbium concentrations up to 4 mol%, after which they decreased, resulting in the concentration quenching effect, whereas decay time decreases as Tb2O3 content increases. In CIE 1931, the overall color of emission is green. May bring can continue to develop to use as a photonic material in green light sources and lasers. [ABSTRACT FROM AUTHOR]

The rapid economic growth in recent years has led to the use of glass material in many activities, resulting in a large amount of glass waste. The efficient use of waste glass recycling has gained increasing attention. Researchers propose a method for recycling waste glass to reduce glass manufacturing costs and investigate the physical, optical, and luminescence properties of chromium oxide-doped glass with the stoichiometry of (35-x) B2O3: 35SiO2 (use waste glass as SiO2): 12Na2O: 7.9CaO: 0.1Sb2O3: 10BaO: xCr2O3 when x = 0.00 to 0.05 mol%. Glass was synthesized using the melt quenching at 1,200 degrees Celsius for 3 h. Archimedes' principle and the Abbe refractometer were used to calculating density and refractive index decrease with the addition of 0.01 mol% of Cr3+ concentration. At room temperature, absorption spectra were analyzed using a UV-VIS-NIR spectrometer exhibiting two broadband at 438 and 625 nm intense bands, and the luminescence properties of the Cr3+ glasses system were investigated using an excitation wavelength of 567 nm, with luminescence peaks observed around 750 nm. CIE L* a* b* shows the green color. [ABSTRACT FROM AUTHOR]

This research assesses the suitability of the Archimedes Optimization Algorithm (AOA) as a metaheuristic technique to fine-tune a PID controller in a closed-loop DC-DC buck converter. The converter's core function is to regulate output voltage, ensuring stability despite load fluctuations and input voltage changes. The operational effectiveness of the converter hinges significantly on the gain settings of the PID controller and determining the optimal gain setting for the PID controller is a nontrivial task. For robust performance, the PID controller necessitates optimal gain settings, attainable through metaheuristic optimization. The algorithm aids in identifying ideal proportional, integral, and derivative gains based on varying load conditions. Leveraging the metaheuristic algorithm, the PID controller is optimized to minimize voltage errors, reduce overshoot, and enhance response time. The proposed PID controller, optimized using AOA, is contrasted with PID controllers tuned via alternative algorithms including the hybrid Nelder-Mead method (AEONM), artificial ecosystembased optimization (AEO), differential evolution (DE), and particle swarm optimizer (PSO). Performance evaluation involves injecting a voltage disturbance into the buck converter with load changes of up to 20%. Results demonstrate the superiority of the AOA-optimized PID controller in voltage recovery. It demonstrates a faster response time and outstanding voltage regulation performance, while also exhibiting minimal performance degradation during load changes. This study concludes that the AOA optimization algorithm surpasses other methods in tuning the PID controller for closed-loop DC-DC buck converters. [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]

This study investigated the morphological features of the ventricular system of the brain in Akkaraman sheep in a measured and structural manner. In the study, 24 adults male Akkaraman sheep, which is a common and hornless breed were used. Anatomical features of the ventricular system were determined by latex injection and dissection, acrylic injection and corrosion cast and magnetic resonance imaging. In the measurements, a precise digital calliper, Archimedes' principle, Cavalieri's principle and ITK‐SNAP imaging were used by comparing them with each other. The average weight of fresh sheep brains was 102 g (0.226 lb), the volume 115.8 mL and the length, height and width were 130.78, 40.58 and 70.08 mm, respectively. The olfactoric bulb contained a cavity associated with the lateral ventricle, large enough to be called a ventricle. The cavity of septum pellucidum has a large cavity was observed. However, there was no cerebrospinal fluid in this cavity. The interventricular foramen of the dissected brain was also an opening measuring 1.4 mm × 3.9 mm × 5.5 mm. The total volume of the ventricles of the brain of Akkaraman sheep was found to be 7107.71 ± 479, 7115 ± 737 and 7080 ± 647 mm3 and 6200 mm3 using the Planimetry, Point Counting method, ITK‐SNAP program, and Archimedes' principle, respectively. In the study, species and breed‐specific brain indices values and many detailed morphometric data were obtained. [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]