This study investigated the impact of boron and copper on the microstructure and mechanical properties of Spheroidal graphite Cast Iron (SCI). The addition of boron increased the ferrite content, while copper increased the stability of pearlite. The interaction between boron and copper significantly increased the ferrite content. Differential Scanning Calorimetry (DSC) revealed that boron decreased the enthalpy change of the α + Fe3C -> γ transformation and increased the enthalpy change of the α -> γ transformation. The addition of boron and copper reduced the tensile and yield strength but increased elongation and impact energy. The findings provide valuable insights into the effect of boron and copper on SCI, facilitating the design and development of high-performance SCI materials.

The theory of heterogeneous nucleation was initially developed as a part of condensed matter physics and later it was used as an important engineering tool to design metallurgical processes. The success leads to wide applications of the theory in metallurgical practice. For example, engineering heterogeneous nucleation in ductile iron has been used to reduce shrinkage defects, suppress cementite formation, and modify size and shape of micro-structural constituencies. This demonstrates how theoretical knowledge could benefit industry practice. This overview aims to summarize the authors’ published studies in co-authorship with colleagues and students, which covered different aspects of engineering heterogeneous nucleation in multiphase cast alloys. Several approaches for engineering heterogeneous nucleation using thermodynamic simulation and practical methods for improving efficiency of nucleation using co-precipitation technique and a local transient melt supersaturation were suggested. Automated Scanning Electron Microscopy Energy-Dispersive-X-ray (SEM/EDX) analysis and a high-resolution Transmission Electron Microscopy (TEM) were used to verify simulation predictions. Practical examples of controlling micro-porosity shrinkage in cast irons with spheroidal graphite are presented to illustrate the power of engineering heterogenous nucleation. The authors appreciate the great efforts that the co-authors have made on the original, overviewed articles here.

The aim of this paper is to introduce a new methodology for the fault diagnosis of induction machines working in transient regime, when time-frequency analysis tools are used. The proposed method relies on the use of the optimized Slepian window for performing the short time Fourier transform (STFT) of the stator current signal. It is shown that for a given sequence length of finite duration the Slepian window has the maximum concentration of energy, greater than can be reached with a gated Gaussian window, which is usually used as analysis window. In this paper the use and optimization of the Slepian window for fault diagnosis of induction machines is theoretically introduced and experimentally validated through the test of a 3.15 MW induction motor with broken bars during the start-up transient. The theoretical analysis and the experimental results show that the use of the Slepian window can highlight the fault components in the current's spectrogram with a significant reduction of the required computational resources.

Articular chondrocytes are surrounded by chondroitin sulfate proteoglycan, which attracts an abundant volume of interstitial water. The articular cartilage is compressed with joint-loading and weight-bearing stresses, followed by a bulging of the tissue during times of off-loading. Thus, osmotic pressure in articular cartilage is higher than in other tissues due to the fixed charged density and altered between loading and off-loading due to change in water content. Another unique characteristic of the articular cartilage is that it has longitudinal depth: surface, middle, and deep zones. Since each zone composes unique components of extracellular matrices, each zone has a various level of the osmotic pressure. It was unclear how changes in osmotic pressure affected chondrocyte homeostasis and matrix accumulation in specific longitudinal zone. We hypothesized that change in extrinsic osmotic pressure alters metabolic functions and histogenesis of extracellular matrix by zone-specific chondrocytes. We compared the gene expression of matrix related typical anabolic and catabolic molecules produced by zone specific articular chondrocytes and the immunohistology of these corresponding genes. Since the newly synthesized matrix needed a space to accumulate, we used a chondrocyte-spheroid model formed by longitudinal depth zone-derived cells and altered extrinsic osmotic pressure by changing media containing different osmotic pressures. Anabolic molecules upregulated continuously at high osmotic pressure and transiently by switching back the osmotic pressure from high to low. Each zone derived chondrocytes showed zone specific level of the gene expression. The spheroids once exposed to the high osmotic pressure accumulated extracellular matrices with empty spaces.