Purpose: A collocation technique based on re-defined quintic B-splines over Crank-Nicolson is presented to solve the Fisher's type equation. We take three cases of aforesaid equation. The stability analysis and rate of convergence are also done.Design/methodology/approach: The quintic B-splines are re-defined which are used for space integration. Taylor series expansion is applied for linearization of the nonlinear terms. The discretization of the problem gives up linear system of equations. A Gaussian elimination method is used to solve these systems.Findings: Three examples are taken for analysis. The analysis gives guarantee that the present method provides much better results than previously presented methods in literature. The stability analysis and rate of convergence show that the method is unconditionally stable and quadratic convergent for Fisher's type equation. Moreover, the present method is simple and easy to implement, so it may be considered as an alternative method to solve PDEs.Originality/value: This work is the original work of authors which is neither published nor submitted anywhere else for publication.

Ti–6Al–4V alloy is used in high-temperature aerospace applications such as aircraft turbine discs, airframes, and other structural parts. Solid particle erosion is quite common in aerospace components. In the present work, a study has been conducted to see the effect of solid particle erosion on Ti–6Al–4V alloy fabricated by direct metal laser sintering. The fabricated sample was characterized using optical microscopy and scanning electron microscopy. It was observed that a long martensitic phase structure (in the form of α/α' laths) was retained since the heat treatment temperature was far below the β transus value. Using the Taguchi experimental approach, the SPE tests were conducted for different impact angles, velocities, and temperatures. This approach optimized the number of experiments for measuring the erosion rate and predicted the most influencing variable in the test. The scanning electron microscopy technique was also used to characterize the eroded sample. The effect of impact velocity dominated the erosion behaviour of Ti–6Al–4V alloy, followed by temperature and impact angle. At highest temperature of 650 K, erosion rate decreased with an increase in impact angle and increased with an increase in impact velocity. This study aims to identify the optimal parameter combination to minimize the erosion rate.

The acoustic behaviour of a classroom is vital for an effective teaching-learning process. The present work aims to experimentally determine the acoustic performance of a typical classroom. The full-scale experiment was conducted at the Seminar Hall, the Department of Applied Mechanics, MNNIT Allahabad, Prayagraj, using a method with limited resource requirements. The Seminar Hall was divided into four planes by threads, and the sound pressure level (SPL) was measured at 30 coordinates in each plane for the specified sound source location. Data were collected from three different sound source locations. The study revealed that the sound source location and frequency significantly influence the sound pressure levels in the classroom, impacting its acoustic performance. The broader implications of interior materials, such as wall material and the position of elements like the teaching board, door, and podium, are highlighted as critical considerations for future classroom acoustic optimization. Furthermore, a numerical model was developed to predict the variation in the SPL with change in the sound source locations and frequencies. The collected data validated with the finite element (FE) model. The verification experiments for the modeling results were performed for each plane. The results of the FE model and experiments were found consistent across all four planes of the seminar hall and the various sound source locations.

An Erratum to this paper has been published: https://doi.org/10.1134/S1061830924070015

Medium entropy alloys (MEAs) have shown potential by replicating mechanical, erosion, and corrosion properties similar to conventional alloys. The present study focuses on the effect of NiCoCr MEA coatings on EN8 carbon steel using laser cladding on microstructure, erosion, and corrosion behavior. The laser cladding technique provides good bonding using a lower dilution rate to the substrate. The in-depth microstructure of the cladding surface was studied using optical microscopy, scanning electron microscopy, and electron backscattered diffraction. The air jet erosion (AJE) study was conducted on the cladded samples at the impact angles of 30°, 60° and 90°. The electrochemical corrosion study was performed in 3.5 wt.% NaCl medium. The microstructure shows the heterogeneity with columnar, cellular and equiaxed regions at different places in all the samples. The NiCoCr MEA-cladded samples showed lower hardness (261.9 ± 6.7 H _V ) than the substrate (281.0 ± 8.1 H _V ). The weight loss of the NiCoCr-cladded samples during AJE process was found lower that the substrate due to lower hardness values. The electrochemical corrosion tests show that the cladded samples provide better corrosion resistance than the substrate. The study highlights on the erosion characteristics and improvement in the corrosion resistance, with potential applications in advanced engineering fields.