Applied Mechanics and Materials Vol. 919

Abstract: A large amount of dust is formed as one of the primary by-products during the blast furnace ironmaking process. Iron and carbon are mainly compositions in the dust. Blast furnace dust (BFD) is cycled to protect the environment and recover valuable components. In this study, BFD is used pelletization process with iron ore concentration for raw materials charging to the iron-making furnace. The mixture of BFD and iron ore (30; 40; 50 by mass %) with 2 % bentonite as a binder was used for making pellets. The produced pellets were tested drop strength and fired at 1200 °C for 30 minutes in the atmosphere environment. Fired pellets were examined compressive strength and reduced at 900; 1000; 1100 °C in 30 minutes. Mechanical, porosity and reduction degree properties of reduced pellets were analysed. The results show that green strength and compressive strength are acceptable values. Good porosity is observed when using a high amount of BFD so that it gives a high degree of reduction. XRD, SEM were used for characterization. Iron whiskers were observed in the sample, which was reduced at 1000 °C. It is clearly shown that the pellets using BFD are appropriated for charging to blast furnace as raw materials.

Abstract: The civil construction area is one of the activities with the highest consumption of raw materials, presenting a large generation of waste. The use of EPS polymer (expanded polystyrene), in addition to being technological, has a low environmental impact by reducing the use of traditional concrete inputs, in addition to being 100% recyclable, cost-effective. The study enabled the elaboration of the composite based on concrete with different contents of recycled expanded polystyrene (EPS) added (0.20; 0.10 and 0.05%, in % weight/weight). The use of this material allowed the partial replacement of standard sand in the composite aggregate, obtaining an environmentally sustainable material, with low specific mass, thermal resistance with insulating, hydrophobic properties that allow low water absorption, with a low impact manufacturing process. This addition of EPS to the fresh concrete mixture showed a reduction in water penetration, making the construction material more hydrophobic, minimizing infiltration problems, reducing the physical process of absorption. The specimens for the concentration of 0.10% (weight/weight) showed better axial mechanical performance, with an average of 11.4 kgf, 52% in gain of reinforcement effect, in relation to the concentration of 0.20% (weight/weight). For this concentration of 0.20 (weight/weight), the EPS beads obtained greater homogeneity in the dispersion in the cementitious matrix, promoting better impact absorption during mechanical efforts. The absorption test was carried out for 10 and 20 minutes, and with that the percentage of water absorbed for each composite was verified. The specimens prepared with higher contents of styrofoam (0.20% and 0.10%), with 0.98 and 1.29%, respectively, of absorbed water, showed a more hydrophobic character due to the higher percentage of presence of pearls. EPS, making the material less permeable to water. The absorption results were quite satisfactory, showing values ​​below 20%, as recommended in the NBR 8491 standard.

Abstract: Resistance spot welding (RSW) is a commonly used process in a variety of fields such as automotive, aerospace, household, furniture, and railway for welding sheet metal parts. These industries further demand a welding machine that is portable and versatile in terms of where it can be utilized, such as, among others, remote locations, and is cost and energy-efficient, reliable, and highly efficient performance-wise. With this aim, the work develops a portable spot-welding machine with specific specifications, of an electrode of 0.394 inches in diameter and 10 inches in length, made of copper, and transformer specifications of 6 V-1500 A with 7 variable current settings. This machine is designed to provide accurate, consistent, and reliable welding readings. Additionally, the machine works on an AC supply of 220 volts, making it easily usable. The machine is found to be cost-effective, with a development cost of only 6100 rupees. It has also been found to be reliable and effective in welding up to two 3 mm mild steel plates under different currents, resistivity, and voltage settings. The machine is simple to operate and user-friendly and with a compact and lightweight design, it is highly versatile and easy to operate for a wide range of welding applications.

Abstract: The tremendous exhaustion of resources, a surprising price increase of petroleum fuel and worldwide ecological issues implement to find renewable fuel for compression ignition engine. Non-edible vegetable oils have proven consensus to opt as a replacement for diesel fuel due to comparable properties and less-pollutant characteristics. Using Unmixed Untreated Non-edible Vegetable Oil (UUNVO) in the CI engine matches the needs of a sustainable future and restricts the intensifying cost involved in biodiesel production. This paper aims to review the influence of various UUNVO (Karanja, Jatropha, Neem, Linseed, Mahua and Rubber Seed etc.) on the important performance parameters and emission level of diesel engine. UUNVO can be fuelled to the unmodified CI engine. However, the viscosity of UUNVO is reasonably higher compare to diesel fuel at room temperature, which deteriorates the engine performance and exhaust emission. Minor changes in the injection line for preheating the UUNVO and operating parameters are the way to improve it. It can clearly understand here that preheated UUNVOs typically increase NO_x emissions and decrease PM, HC, and CO emissions level compared to standard diesel. UUNVO can substitute diesel fuel completely for short-duration operation. With the long-duration operation, UUNVO produces problems like poor engine performance, injector chocking, and erosion of piston crown, rings, cylinder liner, and other internal parts, and degradation of the lubricant. Problems raised due to durability can be minimized by controlling operational parameters.

Abstract: This study presents an analytical investigation of the vibration of fluid-conveying pipes on viscoelastic foundations using the differential transform method. The effects of a new time dependent viscosity parameter in the modified Winkler viscoelastic foundation is studied and analyzed. The governing equation is a fourth-order partial differential equation with pinned-pinned boundary conditions, which required a special analytical method for solution. The differential transform method was applied to obtain the solution of the governing partial differential equation for the fluid-conveying pipes on viscoelastic foundations. The time-dependent viscosity parameter in the modified Winkler viscoelastic model was implemented and simulated to determine the behavior of the viscoelastic foundation. The obtained analytical solution was validated with Runge-Kutta order four numerical method. The effects of foundation stiffness , coefficient of foundation damping and the frequency mass ratio on the governing model equation were investigated. In addition, the bending and deflection of the pipe on a viscoelastic foundation are compared with those on an elastic foundation. The analytical and the numerical solutions are in good agreement. From the study, it is observed that an increase in the foundation stiffness results in increase in the pipe inherent frequencies. Furthermore, the vibration of the pipe on a viscoelastic foundation shows better control and reduction compared with its vibration on an elastic foundation.

Abstract: A wear test was performed under the long-used machine oil sliding environment on Cu-based alloys Al-bronze and α-brass. A pin-on-disc wear testing method was applied where normal pressure of 0.255 to 2.55 MPa and a constant sliding speed of 0.641 m/s were considered. For the assessment dry and fresh machine oil sliding environments were also conducted. The results from the experiment demonstrated that the wear rate and friction coefficient in dry sliding condition were much greater for their direct contact but lower under machine oil due to the reduced roughness by the sealing effect as oil forms a thin lubricating film between the contact surfaces. Used oil displayed some degree of higher wear rate along with friction coefficient due to heavy and harmful chemical compounds in it. Al-bronze performed the better wear properties with lower wear rate and coefficient of friction for all the environments as it achieved the strength through different intermetallic formations. In case of α-brass, it had little effect on wear characteristics. Examined by optical microscopy and SEM analysis, worn surfaces showed that Al-bronze improved wear resistance through mild and smooth abrasive grooves filled with oxides in dry sliding conditions. In case of oil sliding environment, smooth surfaces were created by the resistance of the oil film to the direct contact between the surfaces. Used oil sliding conditions reduced the surface smoothness of the Cu and Cu-based alloys for the presence of damaging chemical compounds.

Abstract: In this work, we examine the effects of viscous dissipation and local thermal non-equilibrium (LTNE) on Couette flow in a duct filled with a porous media under the influence of an angled magnetic field. The bottom plate of the duct is in motion and subjected to a constant heat flux, while the top plate remains stationary and adiabatic. The Jeffrey fluid flow model is consistent with the unidirectional flow in the porous zone. The studies provide more precise measurements of the effects of the Jeffrey parameter (λ), inclined angle (ϕ), Hartmann number (M_W), thermal conductivity ratio (ν), Brinkman number (Br_W), and Biot number (Bi_W) on improving heat transmission. The governing equations are solved analytically. The present investigation gives dimensionless temperatures for fluid-solid phases and fully developed Nusselt number (FDNN) profiles. Variation of Jeffrey parameter, inclined angle, Brinkman number, and Hartman number in the temperature field in both phases and FDNN. Furthermore, the temperature in the solid phase is higher than the temperature in the fluid phase for the Jeffrey parameter and Hartman number in the Couette flow, which supports LTNE validation.

Abstract: Thermoelectric technology is one of the fast-developing technologies in the present days due to its excellent heat transfer and heat conversion capabalities. This uses the electromotive force produced by the temperature difference at each end of the device to produce electricity and vice versa. There are various applications developed based on this thermoelectric technology which includes thermoelectric coolers, thermoelectric generators, and thermoelectric air conditioners. This paper provides a comprehensive analysis of thermoelectric (TE) technologies, starting with a complete summary of their working principles explaining the effects like Seebeck, Peltier, and Thomson effects, as well as optimization techniques, applications, semi-conductor materials used, and potential future developments.

Abstract: With the increasing population, the demand for food products is increasing day by day. The agriculture sector is adapting to technological reforms of traditional processes to maintain a proper balance between the demand-supply relationship. The intervention of the technology is resulting in the enhanced productivity of the agricultural process, and at the same time, it is also helping in the workload management of the farmers. In the last two decades, unmanned aerial vehicles (UAVs) or drones have emerged as indispensable tools in modern agricultural processes. Drones and allied smart technologies are being used for a variety of applications in this sector. This work presents a comprehensive survey of drones in the agriculture sector. The latest trends in the usage of drones from agricultural viewpoints are discussed. The work emphasizes the drone’s architectures, sensor integration, and availability in the open market. Furthermore, the challenges associated with this technology are also outlined.

Abstract: Several advancements in the field of parallel manipulators have taken place in recent days as they offer many advantages over serial manipulators in terms of accuracy, agility, stiffness, speed, etc. The Parallel Kinematic Machines (PKMs) with lower Degree of Freedom (DoF) joints are being explored for a variety of industrial applications and, in particular, machining applications as these offer more accuracy, high machining capability, and more stiffness. This research work focuses on the modeling, kinematics, workspace and dexterity analyses of a 3DoF Translational PKM having coplanar rails along the Cartesian axes: -X, +X, +Y. Actuation of sliders, independently along the respective rails, offer the tool platform pure translational motion. Fixed length links are used to connect the sliders and tool platform. The PKM under study is modeled in CATIA. Inverse kinematics and workspace analysis are carried out using the performance indices, namely, Workspace Volume Index (WVI) and Global Condition Index (GCI). Attempts are also made to find the optimal dimensions of the PKM through multi-objective optimization using Genetic Algorithms in MATLAB. The methodology presented is helpful to predict the PKM's performance capability while the results obtained are helpful for the development of a physical prototype necessary for further experimental investigations.