Hasil untuk "Mechanical industries"

Kiman Silas, Naeemah A. Ibrahim, Umar Abdullahi Isah et al.

The study aimed to optimize the composition and evaluate the performance of briquettes produced from leaves biomass, Arabic gum, and clay for sustainable and eco-friendly energy applications. This study aims to address the challenge of developing sustainable, high-energy-density briquettes from locally available materials to provide an eco-friendly alternative to traditional fuels for energy production. The briquettes were analyzed using Scanning Electron Microscopy (SEM), thermogravimetric analysis (TGA), proximate and ultimate analyses, water boiling test (WBT), and shatter index (SI) tests. Response Surface Methodology (RSM) was employed to optimize the briquette production process by evaluating the effects of binder, biomass and clay. The SEM revealed heterogeneous microstructures with clay contributing to mechanical strength, biomass enhancing porosity, and Arabic gum providing cohesion. TGA showed thermal decomposition stages: drying (100–300 °C), devolatilization (300–420 °C), and char combustion (420–830 °C), with ignition, maximum, and burnout temperatures at 300 °C, 385 °C, and 420 °C, respectively. Proximate analysis reported moisture, ash, volatile matter, and fixed carbon contents as 4.67 %, 35.92 %, 45.33 %, and 40.96 %, respectively, while ultimate analysis revealed high carbon (53.32 %) and low sulfur (0.06 %). WBT efficiency ranged from 36 % to 72 %, with ΔT varying from 26 °C to 56 °C. SI ranged from 20 to 166.6, influenced by binder and clay ratios. Optimal briquettes achieved 56 min burning time and 1.8 min ignition time. The study demonstrates the potential of briquette for producing efficient, durable, and sustainable solid fuel for low to medium energy demand applications.

Minghui WU, Limei CHENG, Qing YIN et al.

The working principle and the main functions of the high-temperature confocal scanning laser microscope (HT-CSLM) are presented. In situ observation of the evolution of high-temperature microstructure of materials can be performed using the HT-CSLM. This is important for studying in detail the processes of material melting, solidification, high-temperature stretching, martensitic transformation, etc. It can also be used in the metallurgical field to study the dissolution, collision, agglomeration, and growth behavior of inclusions. The recent advancements in the aggregation of inclusions using the HT-CSLM are summarized. In-situ observations of collisions, aggregation, and growth of inclusions on the surface of molten steel, slag, and at the steel–slag interface, along with the dynamic studies and model derivations, are included. The collision behavior of non-metallic inclusions at the steel/Ar interface has been analyzed using high-temperature confocal microscopy. This is an important parameter for understanding the collision, agglomeration, and growth behavior of non-metallic inclusions in steel and for exploring the methods to improve steel cleanliness. According to the law of agglomeration of inclusions at the steel/Ar interface, inclusions with similar phases exhibit attraction: the attraction between the solid phases is the strongest, followed by that of the semisolid–semisolid pairs and the liquid–liquid pairs. For inclusions with different states, both attractive and repulsive forces exist simultaneously. The difference between the forces depends on their physical properties, in particular, the contact angle between inclusions and molten steel. Research on the parameters of the capillary force model shows that the effect of the density, size, and contact angle of inclusions is significant on capillary suction, while that of the steel surface tension is relatively weaker. Previous studies have included Al2O3, Al2O3–SiO2, Al2O3–CaO, MgO, Al2O3–MgO, Al2O3–Ce2O3, and Ca–, Si–, and Al-type inclusions in carbon steel. However, there has been limited research on other types of composite inclusions, such as Ti-type oxides and titanium aluminum spinel. The influence of different gradients of the same element on the collision between inclusions should also be taken into consideration. The current model for calculating the attractive force between inclusions is explored, and the impact of factors such as density, size, and distance on the trend of inclusion aggregation and collision in steel is analyzed. The scope for further research on the use of high-temperature confocal microscopy in the field of inclusion collision is also included. The K–P model for calculating the capillary force between inclusions at the steel/Ar interface still has many limitations: a large amount of physical property data, such as the contact angles between various inclusions and the molten steel, is required. This in turn makes the calculation of the magnitude of capillary forces between all inclusions on the surface of the molten steel difficult. Therefore, correcting the K–P model or establishing a new collision model for inclusions on the surface of molten steel is crucial in the study of the collision trend of inclusions on the surface of molten steel.

Rilwan Balogun

Chalcogenide crystals are used in many different industries, but most notably as energy-conversion thermoelectric materials. We have calculated the Seebeck coefficient, electrical conductivity, electronic thermal conductivity, power factor, and figure of merit of MgBS3 (B = Hf, Zr) chalcogenide crystals using semiclassical Boltzmann theory and first-principles calculations. A Quantum Espresso program is used to determine the Fermi level and compute the electronic properties. The transport properties are then computed using the BoltzTraP algorithm. We first make our materials available to the public. We report on our first principle investigation of MgBS3 (B = Hf, Zr), a new class of ternary semiconductor alloys. The structural and elastic properties of these constituents demonstrate their low energy of formation and mechanical stability. In the valence band maximum, the observed electronic energy band gap data show a direct electronic transition including Hf-d states (B = Hf & Zr) along the Γ-symmetry direction, as well as mixed contributions from Mg-s states, Hf-d states, and Zr-d states. Furthermore, to assess the thermoelectric potential of pure MgHfS3 and MgZrS3, the temperature-dependent transport properties were examined. Among the simple measures employed were the "maximum" thermoelectric figure of merit, zT, power factor, Seebeck effect, and their anticipated thermal and electrical conductivity. It provided findings with improved zT values, higher PF, moderate Seebeck effect, and efficient thermal and electrical conductivity compared to the current state of bulk thermoelectric materials. Furthermore, we discover that it is highly improbable to get the necessary zT values for typical device applications by using several additional semiconductors, or chalcogenides perovskites, as described in our work. These results provide an excellent bulk chalcogenide database that is necessary for many potential applications in the renewable energy sector.

Bastos David, Attaei Mahboobeh, Pederneiras Cinthia Maia et al.

The cement and concrete sectors are known for their significant contribution to CO2 emissions. Carbonation curing of concrete precast elements in a CO₂-rich atmosphere is a sustainable approach to reducing the carbon footprint of these industries while simultaneously enhancing the mechanical properties of cement-based materials. This study systematically investigates the influence of mix design and pre- conditioning on CO2 uptake efficiency and the mechanical performance of mortars. The findings highlight that both factors play a crucial role in optimizing carbonation efficiency. Notably, the study demonstrates that maximizing CO2 sequestration of 3 wt.% of the mortar can be achieved through controlled pre-curing while mechanical properties are preserved or even improved. This study confirms that carbonation curing can be seamlessly integrated into the precast concrete manufacturing process without requiring additional processing steps. This breakthrough paves the way for practical implementation in industrial settings, offering the dual benefit of carbon reduction and material performance enhancement.

Maria Cidália R. Castro, Pedro Veiga Rodrigues, Vasco Cruz et al.

The packaging industry has made efforts to reduce food waste and improve the resilience of food systems worldwide. Active food packaging, which incorporates active agents, represents a dynamic area where industry and academia have developed new strategies to produce innovative and sustainable packaging solutions that are more compatible with conventional options. Due to health and environmental concerns, industries have sought alternatives to petroleum-based materials and have found biopolymers to be a viable option because of their biodegradable and safe nature. The combination of PLA/TPS has emerged as an effective system for packaging film; however, they are thermodynamically immiscible. This work highlights the development of a starch-based compatibilizer to connect the PLA and TPS phases by functionalizing maize starch with glycidyl methacrylate, glycerol, or garlic oil. Garlic oil was chosen for its plasticizing ability and antioxidant properties. The films produced exhibited excellent compatibility, with enhanced interfacial adhesion between PLA and TPS components. The introduction of compatibilizers also increased the systems’ crystallinity and improved their mechanical properties. The wettability of the films significantly increased with higher garlic oil content, along with enhanced antioxidant properties. These advancements will enable the production of a compatible PLA/TPS system with improved properties for application in the packaging industry.

Rüstem Binali, Leonardo Rosa Ribeiro da Silva, Danil Yu Pimenov et al.

In contemporary manufacturing industries, composite materials such as carbon fiber reinforced plastics (CFRPs) have become indispensable, finding extensive applications in aerospace, automotive, shipbuilding, high-tech sports equipment, and more. The exceptional chemical, physical, and mechanical properties of CFRPs, including high corrosion resistance, superior strength-to-weight ratio, high fatigue strength, and oxidation resistance, make them highly sought after. However, these very advantages pose significant challenges during machining due to the abrasive nature of composites, anisotropic mechanical properties, and poor thermal conductivity, which collectively exacerbate tool wear. This review paper addresses the critical need for innovative solutions to improve the machinability of CFRPs, a subject of paramount importance for advancing manufacturing efficiency and product quality. It comprehensively examines the latest research progress, current practices, and emerging trends in machining techniques such as turning, drilling (including reaming and countersinking), milling and grinding. The review delves into the influence of various cutting conditions, environments, and tool geometries. It also examines tool textures, materials, and coatings. Additionally, advanced machining methods, including vibration, thermal, and hybrid-assisted machining, are discussed. These factors impact key performance metrics such as cutting forces and torques, tool wear and life, chip morphology, surface roughness, and the quality of machined surfaces, including defect analysis. By synthesizing a vast array of literature for the first time, this paper highlights the most effective strategies to enhance machinability while extending tool life and improving surface finish. Notably, it underscores the innovative use of dry and flood lubrication, minimum quantity lubrication, cryogenic lubrication, and high-pressure cooling. Additionally, it emphasizes optimizing cutting tool geometry, employing diamond tools, and coating tools with TiN and TiAlN, alongside the application of heat treatment and hybrid machining methods, particularly those incorporating vibration machining techniques. This review not only identifies the current challenges but also proposes cutting-edge solutions, making it an essential resource for researchers and practitioners aiming to push the boundaries of CFRP machining technology.

Dr. shaimaa atef Mohamed abdelsalam qura

The furniture industry is one of the important industries in Egypt, of which many complementary industries fall. Many different materials are involved in the furniture industry, which vary in their formation and assembly methods affected by their physical, chemical and mechanical properties. Wood has been used for centuries in the manufacture of furniture and building materials. However, since wood is a natural material, it requires constant maintenance and can degrade faster than other materials, especially since wood constantly gains moisture and loses it due to its properties, resulting in a change in its dimensions and aesthetic appearance. Accordingly, there was a need to use technological progress to improve the properties of wood materials that can be used in the furniture industry, which has a great impact on the design functionally and aesthetically. In this research study, the most important smart wood materials used in interior design and furniture design will be addressed, which are the following types: Wpl “wood plastic laminated board” Rubber wood Flexible ply wood Triangle flexible wood Liquid wood Through the use of these materials, a wood-based product will be manufactured with highly controlled physical and mechanical properties, and then come up with an interior design and design of wooden furniture in its final integrated form that achieves a balance between functionality and contemporary.

Xin Zhang, Zixuan Shao, Muqun Sun et al.

High-strength steels are widely used in various mechanical production and construction industries for their low cost, high strength and high toughness. Among these, bainitic steels have better comprehensive performance relative to martensite and ferrite. In this paper, from the point of view of its microscopic fine structure and mechanical properties, the high-carbon silicon-containing steel Fe-0.99C-1.37Si-0.44Mn-1.04Cr-0.03Ni was austenitized at high temperature after a brief isothermal treatment at 280 °C and is briefly reviewed. We have used EBSD, TEM and 3D-APT to observe a unique transformation in which high-carbon silicon-containing steels form nanostructured bainite with nanometer widths. Intriguingly, as the isothermal duration decreases, the beam bainite width becomes increasingly finer. When the beam bainite width falls below 50 nm, there is a sudden shift in defect type from the conventional edge-type dislocations to a defect characterized by the insertion of a semi-atomic surface in the opposite direction, which leads to different degrees of reduction in the micro- and macro-mechanical properties of high-carbon silicon-containing steels from 1754 MPa to 1667 MPa. This sudden change in the sub-structural properties is typical of the reverse Hall–Petch effect.

Volodymyr Volianiuk, Dmytro Mishchuk, Eugene Gorbatyuk

Loading and unloading works are an integral part of the construction process. Cranes of various types were mostly use to perform these works. To ensure trouble-free operation and increase the reliability of cranes, when calculating structures and components of their working equipment, it is important to take into account dynamic loads, which are several times higher than static loads. Elements of dynamic loads in the crane suspension are its elastic components (flexible traction bodies) - ropes. The process of lifting a load from a rigid base and picking it up is considered, which divided into three stages: the first is the selection of clearances and the tension of the ropes; the second is the pre-opening stage of lifting the load; the third is the post-detachment stage of lifting the load. For each stage, the initial conditions accepted, the differential equations of the movement of loads compiled, their solution given taking into account many factors, and expressions derived for determining the forces in the load suspension. At the first stage, the duration of the gap selection (tension of the ropes) is determined, at the second stage, the speed of separation of the load from the base is determined, at the third stage, the maximum force in the elastic element determined. The method of determining the forces in the suspension of the load, the duration of the selection of clearances (tension of the ropes), the speed of separation of the load from the base, and the maximum force in the elastic element presented in the work allows you to significantly simplify the solution of complex equations, to determine simple expressions and to determine them with sufficient accuracy for practical calculations values.

Sanaz Jafari

Rotating disks are used in industries, such as aerospace, automotive, and power plants. These disks are under time-dependent mechanical loading when the machine starts or stops working conditions. Thermal stresses caused by temperature changes with this time-dependent mechanical load create dangerous conditions. Therefore, the estimation of the elastic limit angular velocity and acceleration as a criterion for the initiation of plastic deformations has special importance in the start-stop process. An analytical Homotopy perturbation method is used to solve the heat transfer equation and the governing Navier equations in both radial and tangential directions of functionally graded rotating disks with non-uniform thickness. The Tamura-Tomoto-Ozawa model is implemented to calculate the yield stress at a different radius of the disk. The obtained results will be verified with the higher-order finite difference method. The effect of thickness parameter, type of thermal and boundary conditions on the angular velocity and acceleration, and also the starting radius of the plastic deformations are investigated by numerical examples. It is shown that by defining the appropriate temperature gradient on the outer surface of the disk and the parameters in the time-dependent angular velocity function, the level of stresses can be controlled and optimized in all working processes.

Penghui Bai, Chunlei Shang, Dexin Zhu et al.

Aluminum alloys are extensively utilized in the transportation and aerospace industries due to their excellent processability and corrosion resistance. A key aspect affecting the application of aluminum alloys is fatigue failure, with fatigue strength constituting an essential indicator for assessing the failure mode. In this study, 859 data sets were collected to evaluate the effects of aluminum alloy composition and mechanical properties on fatigue strength. To comprehensively evaluate the features that exert a great influence on the fatigue strength of wrought aluminum alloys, atomic physical quantities of aluminum alloys were added to the original data set. To improve the computational efficiency and physical interpretability of the model, Spearman correlation analysis, optimal subset method, and other methods were used to perform feature selection on the atomic feature quantities and mechanical properties in the data set. Finally, a mathematical relationship between material descriptors and fatigue strength was established based on the alloy composition and the three most relevant features in the feature screening, which helps to better understand and predict the fatigue behavior of wrought aluminum alloys.

Raji Luqman, Raji Luqman, Abdul-Jeleel Kehinde Issa et al.

Qiuping Ran, Mengtian Huang, Huanan Li et al.

Abstract In the process of bioethanol production, more stable and active cellulase in high temperature condition is required. In this study, syringic acid was applied in cellulase hydrolysis system. At 70°C, TvEG3 activity increased 201.36%, CtBglA activity decreased 72.79% by syringic acid. With syringic acid assisting, TvEG3 thermostability was improved, CtBglA thermostability was reduced. Syringic acid scarcely affected CtCBH. In hydrolysis system with the cellulases containing TvEG3, CtCBH, and CtBglA, the reducing sugar yield improved by 28.37% with syringic acid assisting. With the molecular dynamic simulation in syringic acid system, the backbone root‐mean‐square deviation (RMSD) and the residue root‐mean‐square fluctuation (RMSF) of TvEG3, CtCBH reduced, while the RMSD and RMSF of CtBglA increased. The reduction in the number of secondary structures, especially α‐helix, caused the structure of CtBglA in the presence of syringic acid to collapse at high temperature. More secondary structures in TvEG3 and more α‐helix in CtCBH in the presence of syringic acid make them more stable at high temperatures. These means syringic acid can stabilize TvEG3 and CtCBH structure, destabilize CtBglA structure at high temperature. In summary, this study not only provides insight into cellulase hydrolysis at high temperature with syringic acid assisting but also demonstrates the promoting mechanism of syringic acid.

Emily Caston

The screen advertising production sector as a distinctive sector of film and television production supplying content to the advertising industry. Due to different employment practices, legal and production processes, it has a distinctively different set of issues to theatrical and high end drama. An analysis of a number of case studies of this sector using company accounts and SIC codes, however, shows that it has been rendered invisible in Government commissioned reports. That could be corrected through partnership work between the sector’s trade association the Advertising Producers’ Association. Recognition of the sector’s integration within the UK independent film and television production sector would increase knowledge and understanding of the sector as a whole. This article recommends a theoretical model of horizontal integration of vertical value chains to progress new research in the area and identifies some of the consequences for existing scholarship.

Zhenzhen Gui, Fen Wang, Junyi Zhang et al.

A magnesium alloy processed by equal-channel angular pressing (ECAP) exhibited excellent microstructure refinement and improved strength and hardness. The comprehensive mechanical properties of magnesium alloys have supported the expansion of their applications in the automotive, aerospace, and biomedical industries. Herein, pre-treatment of a solution-treated Mg-2.9Gd-1.5Nd-0.3Zn-0.3Zr alloy was conducted to investigate the precipitate behavior and microstructure evolution during the ECAP process. β1 phase grains quickly precipitated from the solution-treated alloy, which accelerated grain refinement and enhanced the ductility after the ECAP process, as compared to the as-cast alloy reported in our previous study. Moreover, spherical precipitates (∼200 nm) and fine phases (∼100 nm) precipitated along the stripe-like Zn2Zr3 phase, which formed a kabap-like structure dispersing homogeneously in the solution-treated alloy during the ECAP process. Owing to grain refinement, dislocations, spherical β1 precipitates, and texture evolution, the solution-treated alloy after eight passes of ECAP exhibited good comprehensive mechanical properties, with the ultimate tensile strength, yield strength, and elongation values reaching 210.9 MPa, 263.9 MPa, and 27.9%, respectively.

Weerapot Wanajaroen, Christophe Buisset, Thierry Lépine et al.

The Thai Space Consortium aims at building capacities in space technologies and industries with the objective to develop satellites in Thailand. In this framework, the first Earth Observation satellite that will be developed by this consortium is called TSC-1. This satellite comprises a hyperspectral imager orbiting in a Sun-Synchronous Low-Earth Orbit at the altitude equal to 630 km. The optical payload is specified to provide data cubes with a Ground Sample Distance equal to 30 m, a swath equal to 30 km, a spectral resolution equal to 10 nm over the spectral domain from 400 nm to 1000 nm with a Signal-to-Noise Ratio (SNR) higher than 100. Firstly, we present the trade-off performed to select the design of the Front Telescope and the Spectrometer. Secondly, we describe the payload design and present the image quality, Modulation Transfer Function and distortion. Next, we establish the tolerance budget to estimate the performance of the optical system including manufacturing errors, assembly errors and stability of the mechanical structure. After that, we calculate the instrument’s spatial and spectral response functions and the contamination of the adjacent pixels due to the straylight. Finally, we estimate radiometric performance in both nadir pointing mode and forward motion compensation mode.

Nthateng Nkhasi, Willie du Preez, Hertzog Bissett

Metal powders suitable for use in powder bed additive manufacturing processes should ideally be spherical, dense, chemically pure and of a specified particle size distribution. Ti6Al4V is commonly used in the aerospace, medical and automotive industries due to its high strength-to-weight ratio and excellent corrosion resistance properties. Interstitial impurities in titanium alloys have an impact upon mechanical properties, particularly oxygen, nitrogen, hydrogen and carbon. The plasma spheroidisation process can be used to spheroidise metal powder consisting of irregularly shaped particles. In this study, the plasma spheroidisation of metal powder was performed on Ti6Al4V powder consisting of irregularly shaped particles. The properties of the powder relevant for powder bed fusion that were determined included the particle size distribution, morphology, particle porosity and chemical composition. Conclusions were drawn regarding the viability of using this process to produce powder suitable for additive manufacturing.

Ehsan Mohammadpour, Willey Yun Hsien Liew, Nik Radevski et al.

High temperature thermal-mechanical stability of tribological thin coatings is extremely important to a large number of applications in modern industries. DC magnetron sputtering of single metallic element (Cr, Si) and alloy (Ni:Cr) targets formed transition metal nitrides film coatings, CrSiN and CrNiN onto M2 steel. High temperature in-situ synchrotron X-ray diffraction, in the range 25 °C–700 °C, obtained experimental data for a range of structural and mechanical properties. Furthermore, experimental room temperature Nanoindentation measurements, made before and after the in-situ heating cycle, provided corresponding hardness and shear modulus results. The structural results identified microstructure and phase transformation changes, while the mechanical results identified microstrain, hardness, elastic modulus and deformation resistance properties of the coatings. Density functional theory (DFT) and quasi-harmonic approximation (QHA) modelled the high temperature thermal and mechanical properties such as: Young's modulus, shear modulus and thermal expansion coefficients (populated up to 1200 °C). Estimates of hardness are made by correlating the bulk phase hardness and shear modulus, of the CrN and Ni phases, as a function of temperature. Results indicate that Si doping enhances the hardness of the CrN framework, increasing from 29 to 36 GPa and improves the coatings elastic modulus, and resistance to deformation. However the addition of Ni reduced these properties. Furthermore, formation of (Cr,Si)N and Ni(Cr) solid solutions is inferred from DFT, Rietveld and lattice constant analysis.

Isaev Alexander, Khamzin Ramil, Minin Ilya et al.

Micromachining is an increasingly important material cutting process which is performed on workpieces in micro-scale. It is widely used in rapidly developing advanced areas like electronic, aerospace and medical industries. In medical industry, micromachining is applied for producing instruments, joint implants and dentures. The medical components should be made only of biologically compatible and hard-to- machine materials such as cobalt and nickel based alloys, ceramics and titanium alloys. For manufacturing medical components, small-sized end mills with working diameter of less than 1 mm are often used. Such micro milling cutters impose difficulties on the mechanical micromachining process. To determine the functional relationships between structural strength, cutting properties and geometry of a micro milling cutter, a mathematical model is derived in this paper. Before experimental phase, the calculation of cutting forces was performed as this will reduce the time to determine the optimal cutting data and maximize the tool life.

W. Woo, J. S. Jeong, D.-K. Kim et al.

Abstract Stacking fault energies (SFE) were determined in additively manufactured (AM) stainless steel (SS 316 L) and equiatomic CrCoNi medium-entropy alloys. AM specimens were fabricated via directed energy deposition and tensile loaded at room temperature. In situ neutron diffraction was performed to obtain a number of faulting-embedded diffraction peaks simultaneously from a set of (hkl) grains during deformation. The peak profiles diffracted from imperfect crystal structures were analyzed to correlate stacking fault probabilities and mean-square lattice strains to the SFE. The result shows that averaged SFEs are 32.8 mJ/m2 for the AM SS 316 L and 15.1 mJ/m2 for the AM CrCoNi alloys. Meanwhile, during deformation, the SFE varies from 46 to 21 mJ/m2 (AM SS 316 L) and 24 to 11 mJ/m2 (AM CrCoNi) from initial to stabilized stages, respectively. The transient SFEs are attributed to the deformation activity changes from dislocation slip to twinning as straining. The twinning deformation substructure and atomic stacking faults were confirmed by electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). The significant variance of the SFE suggests the critical twinning stress as 830 ± 25 MPa for the AM SS 316 L and 790 ± 40 MPa for AM CrCoNi, respectively.