Key Engineering Materials

A solar basin still with the cross - section of 100 cm × 100 cm and an inclination of 11o was fabricated and experimented at St. Mother Theresa Engineering College, Tuticorin, Tamilnadu, India, at (11.9310° N, 79.7852° E). In order to accelerate heat transfer the surface was painted dark black, the basin was provided with fins and a reflecting mirror was placed at the base surface. In addition, a solar-powered pond with a top surface area measuring 90 cm x 90 cm and a base surface area measuring 30 cm x 30 cm, equipped with fins at its base and the top of the pond is affixed with reflecting mirrors for storing more heat intensity inside the solar pond. The pond was sectioned into three layers based on the rate of heat transfer: Upper converting layer (UCL), Middle converting layer (MCL), and Lower converting layer (LCL). The primary investigation was carried out on January, February, and March 2023 and the readings were noted for eight hours a day on a regular basis. The lower converting layer experienced the high radiation strike of the sun during the day yielding the optimal output. This paper discusses the results of the experiments conducted on the solar still with a single basin that was connected to a solar-powered sectioned pond.

Digital Light Processing (DLP) 3D printing is an additive manufacturing technique that uses a digital light projector to cure photopolymer resin layer-by-layer to create high-precision solid structures. In addition to the planar resolution, the control of curing depth has a critical impact on the success of precise printing and the geometric features of the printed product. This issue is aggravated in the case of projection micro-stereolithography (PμSL), which uses an objective lens to enhance the planar resolution of the projected pattern. In this study, we investigated possible measures to control the cured layer thickness from both material and optical perspectives. As-received commercial resin was used to obtain the raw cured layer thickness, and then Sudan I or carbon black was added separately to study their effects. Eventually, the grayscale of the exposed pattern was adjusted to reduce light intensity and achieve a thinner layer thickness. Combining the above measures reduced the single-layer cured thickness from the raw 250 μm to 5.8 μm, approaching the usual minimum layer dimension setting of 5 μm. By exploring the variables affecting cured layer thickness, the findings in this study are expected to improve DLP 3D printing technology in producing high-resolution structures, especially in the z-direction.

Solar desalination efficiency can be significantly altered by combining several approaches to improve evaporation rate. The objective of this research is to find a way to make solar stills (SS) more efficient by combining evacuated tube solar collectors, blue metal stones, and corrugated fins. An investigation into a six-tube evacuated solar collector was conducted to increase the system's evaporation rate. Corrugated fins were thought of to rise the surface area of heat transfer between the water and absorber. Blue metal stone was proposed to keep the water at a maximum temperature even when solar radiation is minimal. Separate displays of the cumulative distillate output (DO) numbers and hourly values for each time period provide a comprehensive view. Based on the findings, the peak period for DO moves from 1 p.m. on a sample day in May 2024, which is six months into the project. In comparison to CSS, MSS temperature values are over 55 °C higher at the peak and nearly 26 °C higher on average. On top of that, the total DO during the day can reach 2.64 to 6.82 L, while at night it rises from 0.067 to 0.96 L. In addition, there is a 146.3% improvement in the average DO during the six months, going from 3.02 to 7.22 L. Additionally, MSS is 0.43₹ per liter and CSS is 0.47₹ per liter, in that order. The net amount of carbon dioxide reduction achieved by modified solar stills was approximately 2.44 times greater than that of conventional solar stills.

Questions arise whether construction delay combined with construction method modification of a long-span bridge will affect bridge resistance to withstand the working load in the long term. A continuous bridge with a span of 78 m - 145 m - 77 m that crosses a large river has experienced this condition. In its implementation, there was a difference in construction time compared to the initial design. As a result, it is necessary to conduct an analysis of the effects of the difference in construction time on the bridge structure. An analysis of the stages of bridge construction was carried out using the Midas Civil program to determine the stress and deflection that occurred. Stress and deflection over a long period of time were calculated to determine the effect of construction methods and delays.

Long-span bridges are generally often needed in the world of civil engineering to reduce the number of the bridge piers. A long span steel box girders with a mid-span of 120-meter and two side-spans of 70-meter is studied. The static bridge deflection needs to be evaluated as the constructed slab thicknesses of the steel I-girder composite slab was not constant along the bridge longitudinal span. Results from numerical simulation with those of loading tests carried out on the bridge after its completion are compared.

Bio-based materials and phase change materials (PCMs) are currently being gradually noticed and emphasized as passive building envelopes. This study focuses on the effect of PCM placement and phase transition temperature on hygrothermal and energy performance. Systematic studies reveal that placing PCM with a phase transition temperature of 24-28 °C in the scenario PCM middle provides considerable results, reducing the summer temperature and relative humidity amplitude, heat load and moisture load by 5%, 0.03%, 8% and 5.8%, respectively. Besides, performance is further optimized with the scenario PCM middle of phase transition temperature of 26-30 °C, with the reductions in temperature and relative humidity fluctuations, heat load and moisture load by 88.6%, 85.4%, 69.65% and 69.63%, respectively. Overall, strategic PCM placement and phase transition temperature improve building energy efficiency and comfort, offering valuable insights for designing bio-based concrete structures.

The development of physiological detection is advancing rapidly, driven largely by the increase in the awareness of sport, healthcare, and biomedical knowledge. Wearable electronics have been integrated into real-world physiological sensing applications, with many recent studies aimed at enhancing their capabilities from both material selection and fabrication perspectives. To create the best fit for specific wearers, three-dimensional (3D) printing is an excellent candidate because of its potential to create structures ranging from simple to highly complex. This work investigates the effect of infill densities (20%, 40%, and 60%) on the electromechanical properties of 3D-printed thermoplastic polyurethane (TPU) using fused deposition modeling (FDM). The printing conditions were consistently controlled throughout the study, specifically using a honeycomb infill pattern. The flexible TPU substrates were successfully 3D-printed, and 1% w/v of multiwalled carbon nanotubes (MWCNTs) were embedded in the 3D-printed samples using an ultrasonic cavitation-enabled treatment and thermal-assisted method. This process aims to prevent CNT fallout while maintaining the compression load-bearing capacity. A compressive load of 10 kN was applied to the samples during electromechanical testing. The results show that a 20% infill density provides the optimum sensitivity of 11.32 MPa⁻¹ at 2V applied voltage due to its appropriate current path, which is confirmed by scanning electron microscope (SEM). The dimension accuracy of the 3D-printed TPU samples tend to increase with higher infill densities and application of the double treatment.

Due to the demeaning character of fossil fuels and their detrimental harmful effects on the ecosystem, studies have focused on finding appropriate non-edible replacements. In the present research, the emissions and performance features of the blends of biodiesel generated from the chosen raw materials (flamboyant seed), which includes B25, B50, B75, and B100, were evaluated in the early stages of the research. A diesel engine continues to operate at an authorized rate of 1500 rpm. In the following phase of the research, the focus is on defining the appropriate blend's performance as well as its emission characteristics under the ideal operating circumstances. The FME blend B25 is found to be satisfactory, and the optimal parameters to stated standards have been CR 18.5.With the exception of NOX emission, the ideal blend surpassed alternatives in terms of BSFC and BTHE associated with reduced CO and HC outputs. The optimum fuel's BSFC and BTHE at the maximum load, for CR 18.5, are 0.257 kg/kW-hr and 31.47%, respectively. The emission levels of CO, HC, and NOX are 0.08%, 51 ppm, and 1029 ppm.

The micro and nano structures of porous material have strong influence on their transfer properties such as porosity, permeability, tortuosity and adsorption isotherm curves. In the construction and building material field, these properties are strongly related to hydro and thermal comfort, due to the fact that heat and mass transfer mechanisms are determined by the micro porous structure. In the present work, we aim to predict heat and mass transfer on such micro-nano structured materials, with a statistical quantification method that is extracted from morphology aspect. A large range of the pore size (from 20nm to 1mm) is covered and investigated by the multiple approaches, including FIB-SEM, X-Ray Tomography, and MIP (Mercury Intrusion Porosimetry). The 3D view of pore structures is obtained in concrete, as well as their size distribution, and pore zones. A reconstruct of 3D view of pore networks is extracted, with the spatial resolution of 20 nm/pixel. A global view of multiple testing methods and the corresponding size ranges are drawn to summarize the multi-scale approaches, for a potential further understanding of relationship between porous structure and thermal-hydro properties.

To perform a comparative study of the performance combustion and emission characteristics of pure diesel and mustered blends, a single-cylinder stationary Kirloskar TV1 Engine.xls engine was used. The ratio of mustered oil blends to diesel was 60%. The mustered blend was selected appropriately and the compression ratio was optimized for this study. From this report it is proven that the most favorable of mustered and diesel blends is 60% of mustered and 40% of diesel with compression ratio 14:1,15:1,16:1 & 17.5:1.In comparison, the release of CO was reduced; however, there was a moderate increase in the release of NOx. Therefore, with only a slight alteration in the present diesel engines, the algae blend can be used.

Nowadays, the requirements of scaffolds and bone grafts are increasing along with large defects increasing every year. Furthermore, large defects that occur in human bones are customary. However, this obstacle can be overcome by using 3D printing. This study aims to investigate the morphology, deviation dimension, shrinkage and hardness of hydroxyapatite (HA)/collagen composite, which these materials mimic with human bone. HA/collagen composite was printed using three-dimensional bioprinting based on extrusion with a print speed of 10 mm/min and a layer height of 0.5 mm. The composition of HA and collagen material is 70% and 30%, respectively, where this composition mimics natural bone. Morphology and dimension of HA/collagen composite were obtained by transmission electron microscope. Moreover, the deviation dimension and shrinkage were measured using the Miviewcap optical microscope and software Image J. The resulting HA/collagen composite clearly showed that collagen was in the form of fibers while HA was in an irregular shape. The average width and length of collagen were 5.98 + 0.20 nm and 82.48 + 6.23 nm, respectively. Moreover, the Average width and length of HA were 21.85 + 0.53 nm and 23.30 + 1.33 nm. The average deviation dimension in the X, Y, and Z axes was 2.69%, 1.40%, and 24.12%. Furthermore, shrinkage was 12.27%, 10.18%, and 19.06% on the X, Y, and Z axes. The average hardness of specimen 1 and 2 of HA/collagen composite were 0.0021594 HV.

An exact analytical solution to the problem of plane transverse bending of a section of a narrow multilayer beam under the action of a normal load on the longitudinal faces, distributed according to the law of the trapezoid, is presented. The solution is constructed using the principle of superposition on the basis of the authors’ general solutions to the problems of bending multilayer consoles under the action of loads at the free end, uniformly and linearly distributed load on longitudinal faces. On its basis, separate interchanges for multilayer beams with different methods of fixing the ends were obtained: hinged, rigid and combined. The obtained relations make it possible to determine the stress-strain state of multilayer beams with an arbitrary number of homogeneous (orthotropic, isotropic) and functional-gradient layers, taking into account transverse shear and compression deformations.

Magnetite (Fe₃O₄) nanoparticles have garnered significant attention in biomedicine due to their distinctive magnetic properties, biocompatibility, and ease of functionalization for diverse applications. In this study, Fe₃O₄ nanoparticles were synthesized via the co-precipitation method, followed by the synthesis of a SiO₂ coating on Fe₃O₄ (Fe₃O₄@SiO₂) and an amino group coating on Fe₃O₄@SiO₂ (Fe₃O₄@SiO2_NH2) before chitosan coating. Chitosan concentration was varied at 1% and 5% to improve their stability and biocompatibility. Characterization of the nanoparticles was conducted using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDXS). XRD analysis confirmed that the synthesized nanoparticles were magnetite (Fe₃O₄), while FTIR confirmed the presence of -OH and -NH₂ functional groups, which increased after coating with a chitosan layer on the magnetite surface. SEM/EDX analysis revealed that the average diameter of the uncoated Fe₃O₄ nanoparticles was approximately 12 nm, and EDX analysis indicated the presence of sodium after coating with chitosan. Using chitosan as a coating material enhanced the biocompatibility, stability, and functional versatility of the nanoparticles. The results demonstrated the successful coating of chitosan on the Fe₃O₄ nanoparticles, which retained their superparamagnetic properties, making them promising candidates for drug delivery applications.

Vietnam is one of the largest rice producers in Southeast Asia, generating substantial quantities of rice husk as a by-product of rice milling. Currently, rice husk is predominantly disposed of as agricultural waste. This study investigates the utilization of rice husk to synthesize silicon carbide (SiC) and crystal silica (SiO2). The device for the experiment was built by the authors with simple accessories. SiC and crystal SiO2 from rice husk were synthesized successfully at low temperatures compared to a chemical reaction of silica reduced by carbon. The research outlines the production conditions for achieving a little SiC from recycled rice husk and explores potential development pathways for applying this technology in structural and material manufacturing industries. The characterization of the synthesized SiC was measured using X-ray diffraction (XRD) and scanning electron microscopy (SEM).

An analytical method for calculating the bending of ring plates resting on a non-homogeneous elastic Winkler foundation has been developed for the case when the bedding factor and load are given by any continuous functions. The method is based on the exact solution of the corresponding differential equation. Calculation formulas for the parameters of the stress-strain state of the plate are given in closed form. An example illustrates the practical application of the developed method. The case is considered when the bedding factor changes according to the parabolic law, and the load is given by the sine law. Calculation results are presented in numerical and graphic formats. For comparison, the calculation results obtained by the finite element method are also provided.

Temperature and steel fiber content have a great influence on the mechanical behavior of concrete, so it is urgent to study the mechanical properties of concrete at different temperatures and steel fiber content. The effects of temperature and steel fiber content on the mechanical properties of concrete are studied in this paper. Based on the uniaxial compression testing machine, the uniaxial compression tests of concrete under different temperatures (150°C, 300°C, 450°C) and different steel fiber content (0%, 1%, 2%, 3%) are carried out. With the increase of temperature, the compressive strength of concrete first increases and then decreases, which indicates that there is a critical temperature for the influence of temperature on the compressive strength of concrete. In addition, the addition of steel fiber content significantly improves the compressive strength of concrete. In addition, temperature and steel fiber content significantly affect the peak strain of concrete. Based on the SEM test results, the temperature effect of concrete was investigated from the microscopic perspective.

In the process of iron production in a blast furnace, a large amount of dust is generated as a by-product. The main components of this dust include iron and carbon, so a circular process should be implemented to protect the environment and reduce production costs. In this investigation, blast furnace dust (BFD) was used to produce pellets with iron ore as raw charging materials into the blast furnace. The mixture consists of BFD, iron ore, and 2 % in mass of bentonite as a binder in the pelletization process, with the ratio of BFD in the mixtures with fine iron ore being 0:100, 10:90, 20:80, and 30;70, respectively. Green pellets were dried at 105 °C for 24 hours obtaining dried pellets. Dried pellets are fired at 1200 °C in the atmosphere for 60 minutes to achieve the required mechanical properties obtaining fired pellets. The fired pellets were reduced at 1000 °C and 1100 °C for 45 minutes by coke breeze. XRD and SEM were then used to analyze the properties of the pellets. The results showed that the pellets exhibited improved metallurgical properties, making them suitable for charging material into the blast furnace.

A new version of the mathematical theory of non-thin multilayer nonlinearly elastic Kauderer plates of symmetric structures has been constructed. The components of the stress-strain state (SSS) and boundary conditions on the side surface of the plate are considered functions of three spatial coordinates. The variant is based on the development of components of the SSS of the plate along the transverse coordinate with the help of combinations of Legendre polynomials within each layer. The three-dimensional physically nonlinear boundary value problem for a multilayer non-thin plate is reduced to a two-dimensional one using the three-dimensional equations of the theory of elasticity and Reissner's variational principle. The main dependencies are obtained. Derived systems of high-order differential equations of equilibrium with partial derivatives and boundary conditions containing nonlinear terms from the SSS. The conjugation conditions at the boundary of adjacent layers (rigid connection) are exactly fulfilled for displacements, transverse tangential and normal stresses. The boundary conditions for stresses on the horizontal faces of the plate are also exactly fulfilled. The system of high-order differential equations of equilibrium is transformed into two systems that independently describe skew-symmetric and symmetric deformation relative to the median plane of the plate. In turn, each of these systems is transformed into differential equations that describe vortex boundary effects and equations that describe an internal SSS with a potential boundary layer-type boundary effect. The solution of systems of high-order equations by the developed method is reduced to the solution of second-order differential equations (Poisson and Helmholtz equations). General solutions of the system of differential equilibrium equations are obtained. The validity and accuracy of the variant of the mathematical theory is confirmed by comparisons with exact solutions of bending problems for linearly elastic plates with different mechanical and geometrical parameters. The newly constructed variant of the theory and the developed method provide a real opportunity to solve boundary problems in a spatial formulation with high accuracy for multilayer platens under various loads and boundary conditions on the lateral surface.

This study uses direct microwave heating to investigate the direct reduction process in carbon-iron ore composite briquettes under varying pressing forces. The composite briquettes, made from magnetite iron ore concentrate, anthracite coal, and bentonite as binder, were pressed at 1-ton, 2-ton, and 3-ton loads and then subjected to microwave irradiation. X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy were employed to analyze the phase composition and structural changes. The results show that the 1-ton briquettes exhibited predominantly metallic Fe with minor fayalite and FeO phases, whereas the 2-ton and 3-ton samples displayed increased fayalite formation. Notably, re-oxidation occurred in the 2-ton and 3-ton samples, as indicated by the presence of Fe₃O₄. The higher pressing forces caused reduced air permeability and lower CO diffusion efficiency, hindering the reduction process. These findings highlight the influence of compaction pressure on the reduction process and the potential of microwave heating as an energy-efficient alternative in ironmaking.

This study investigates the medicinal potential of proteins derived from Phallus indusiatus, commonly known as bamboo mushroom, focusing on their bioactive properties of the mushroom proteins, including antioxidant, anticancer and anti-inflammatory effects. Using a non-solvent extraction method, crude proteins were isolated and purified through anion-exchange chromatography. After stepwise NaCl elution, distinct eluted peaks were collected, designated P1-P4 fraction. Each purified protein fractions primarily demonstrated moderate antioxidant activity. Bioactivity assessments were further conducted on several protein fractions (P1, P2, P3, and P4) using LPS-stimulated RAW264.7 cells to evaluate their anti-inflammatory properties. The results revealed that proteins P1, P3, and P4 significantly reduced nitric oxide production, with P4 demonstrating the most potent effect. As the results, P1, P3, and P4 would be exhibited as Fungal Immunomodulatory Proteins (FIPs) with selective anti-inflammatory activity, suggesting their potential for further therapeutic applications. Anticancer activity was assessed against A549, where all protein fractions exhibited notable cytotoxicity against cancer cell, without affecting normal Vero cells. These findings highlight the potential of P. indusiatus proteins containing pharmacological properties for developing mushroom-based meat analogs.

Reinforced concrete (RC) bearing walls are commonly used in building structures to resist axial and lateral loads. Therefore, their ability to withstand loads when exposed to fire is important. The behavior of RC walls under fire exposure is affected by various factors, such as slenderness ratio, concrete strength and composition, and axial load. This paper investigates the effect of slenderness ratio on the structural performance of RC walls subjected to fire. A series of numerical simulations were conducted on RC walls with different slenderness ratios. The simulations are performed on a three-dimensional (3D) finite element (FE) model, after validating its thermal and structural behavior using previously published experimental data. The walls were exposed to standard fire curves (ISO834) on one side. The thermal and structural response of the walls were assessed in terms of axial deformations, out-of-plane deformations, and fire resistance. The results showed that slenderness ratio had a significant influence on the fire behavior of RC walls. The walls with higher slenderness ratios exhibited higher temperature gradients and larger deflections compared to the walls with lower slenderness ratios. Moreover, the fire resistance of the walls was significantly reduced when the slenderness ratio was increased.

This paper presents a study from an ongoing research project on the bond performance of flexural prisms strengthened using carbon-fiber-reinforced polymer (CFRP) laminates. The primary objective is to evaluate the effect of normal-strength concrete (NSC – 30MPa) and high-strength concrete (HSC - 50MPa) on the bond performance of plain concrete prisms notched at the mid-span and strengthened using CFRP laminates. Six of the twelve plain concrete prisms were strengthened using CFRP laminates, while the remaining prisms were unstrengthened to serve as control specimens. After achieving 28 days of curing in standard lab conditions, all prisms were tested under a four-point bending test. The ultimate mid-span deflection, maximum and ultimate strains at the mid-span, strain distribution at different positions along the length of the laminate, and bond/shear stress versus slip were analyzed to evaluate the bond performance of flexural prisms. The average ultimate load-carrying capacities and mid-span deflection of the NSC and HSC groups were 31.33 and 35.02 kN and 0.55 and 1.54 mm, respectively. The average CFRP strain values at the mid-span corresponding to the ultimate load were 5005 and 3544 με for the NSC and HSC groups, respectively. The maximum attained bond-stress values for NSC and HSC groups were 1.71 and 1.42 MPa, respectively. The corresponding values for slip at maximum bond stress are 0.27 and 0.24 mm for the two groups, respectively. It was concluded from the study that the concrete compressive strength has minimal effect on the flexural bond performance of concrete prisms externally bonded with CFRP laminates.

Desert soils present some issues that need improvement. Some of these are high permeability and collapsibility potential. These problems are due to the uniform particle size distribution and the lack of particle edges. Soil improvement is required to mitigate these issues. Cement is widely used for soil stabilization but has environmental issues since it is a significant source of CO2 emissions and requires high energy consumption. In this study, the calcined shale material is utilized as a partial replacement for cement to reduce the permeability and compressibility of soils more sustainably. The study considers three cement doses of 5%, 10%, and 15% and four calcined shale percentages of 10, 30, 50, and 70%. A series of falling head permeability and one-dimensional consolidation tests were conducted to examine the performance of cement and calcined shale as stabilizers. The results of the study indicate that the addition of 30% calcined shale as a partial replacement of cement has the most significant effect on the conductivity and compressibility of the soils. An increase in cement content decreases the permeability and compressibility of the soil due to the hydration of cement. Conversely, the conductivity and consolidation of the soil are initially decreased with an increase in the calcined shale up to 30% and then start to increase. In summary, this study reveals that the presence of CS and cement has a substantial effect on the conductivity and compressibility of the soils.

In this study, an adhesive was prepared using waste polystyrene foam for wood-to-wood bonding. The effects of natural rubber (NR) and methylene diphenyl diisocyanate (MDI) content on adhesion were investigated. NR modifies polystyrene, acting as a plasticizer to address its hardness and brittleness, while MDI functions as a curing agent for the adhesive system. Characteristics such as the viscosity and wettability of the liquid adhesive were determined. Differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) were employed to evaluate the properties and structure of the resulting adhesive films. The bonding ability between two wood plates using this adhesive was evaluated through tensile shear strength and impact strength. An experimental plan was devised to identify the optimal content of NR and MDI, providing the highest tensile shear strength and impact strength of the bond. The research revealed that the highest tensile shear strength achieved was 3.87 N/mm² at 16.468% NR and 7.882 phr MDI, while the highest impact strength reached 15.352 kJ/m² with NR and MDI contents of 16.079% and 7.620 phr, respectively. The experimental planning models demonstrated a good fit for predicting tensile shear strength and impact strength.

Since electric arc furnace dust (EAFD) contains a certain amount of zinc (Zn), recovery of this metal is important. Many methods have been applied to recover Zn from EAFD so far. Pyro- and hydrometallurgical methods are recommended for this purpose. EAFD was leached using an ammonia carbonate solution, but the leached residue still had an amount of Zn that needed to be recovered. In the present study, the residue was mixed with coke, compressed into pellets, and heated at 1000 - 1200 °C for 30 - 90 minutes to investigate the reducing ability of the Zn compound. The residue was characterized by wet chemical analysis and the XRD method. The Zn content of heated pellets was analyzed to calculate the Zn removal efficiency. The obtained results showed that higher temperatures provided a strongly reducing reaction, the Zn removal efficiency was higher than 90 % for the pellet heated at 1100 °C for 60 minutes. It was concluded that combining the leaching method and carbothermic reduction could recover all amounts of Zn in the EAFD.