Thermal expansion study of a uvarovite rich garnet

Thermal expansion measurements have been performed on a uvarovite rich garnet sample for the first time and compared with the expansion data on grossular and pyrope-rich garnets reported in the literature. A semiclassical model has been used to analyze the data and to obtain various thermodynamic parameters. Using these parameters, the lattice specific heat and the corresponding entropy have also been calculated. © World Scientific Publishing Company

Sugarcane Bagasse-Derived Activated Carbon- (AC-) Epoxy Vitrimer Biocomposite: Thermomechanical and Self-Healing Performance

Vitrimeric materials have emerged as fascinating and sustainable materials owing to their malleability, reprocessability, and recyclability. Sustainable vitrimeric materials can be prepared by reinforcing polymeric matrix with bioderived fillers. In the current work, a sustainable vitrimer is prepared by incorporating biomass-derived activated carbon (AC) filler into the epoxy matrix to achieve enhanced thermal and mechanical properties. Thus, prepared biocomposite vitrimers demonstrate a lower-temperature self-healing (70°C for 5 min) via disulfide exchanges, compared to the pristine epoxy vitrimers (80°C for 5 min). Significantly, the self-healing performances have been studied extensively with the flexural studies; and changes in material healing efficiency have been demonstrated based on the observed changes in modulus

Introduction to general relativity

INTRODUCTION TO GENERAL RELATIVITY begins with a description of the geometry of curved space, explaining geodesics, parallel transport, covariant differentiation, geodesic deviation and spacetime symmetry by killing vectors. It then introduces Einstein's theory of gravitation followed by Schwarzschild solution with its relevance to Positive Mass theorem. The three tests for Einstein's gravity are explained. Other exact solutions such as Vaidya, Kerr and Reisner - Nordstrom metric are included. In the Chapter on cosmological solutions, a detailed description of Godel metric is provided. It then introduces five dimensional spacetime of Kaluza showing the unification of gravity with electromagnetism. This is extended to include non-Abelian gauge theory by invoking compact extra dimensions. Explicit expressions in this case for Christoffel connections and ricci tensor are derived and the higher dimensional gravity action is shown to compactification are given

Evolutionary Patterns of Flexible Automation and Performance: A Longitudinal Study

This study presents a longitudinal analysis of patterns of investment in advanced manufacturing technologies (AMT) and financial performance. Investments in AMT from 112 manufacturing plants in the metal-working industries are examined. Data were collected via a mail survey administered to 202 plants in 1994, and readministered to 112 of the same plants in 1996. This study seeks to fill a void in the area of technology management, which is comprised primarily of cross-sectional studies that do not address the dynamic nature of investments in technology. Four major conclusions are drawn from the data. First, several individual technologies have higher investments in 1996 than in 1994. In particular, electronic mail has the largest increase in investment, a finding that suggests that manufacturing firms are finding ways to take advantage of the exploding potential of electronic communication. Our second conclusion is that plants invest in technology in an incremental fashion over time rather than using an all-or-nothing approach. Plants with low investments follow one of three technology strategies as their investments in AMTs evolve: (1) continued low investment, (2) investment primarily in design-based technologies, or (3) equalized investment in design, manufacturing, and administrative AMTs. Third, analysis of the degree of manufacturing involvement in developing business strategy indicates that plants that have a more proactive role for manufacturing invest greater resources in AMTs. Finally, while AMT investment was not positively associated with performance in a cross-sectional analysis, longitudinal analysis of data collected two years later does reveal a relationship. In short, the analysis supports the proposition that there is a lag between initial investment and resulting performance improvements.advanced manufacturing technology, technology management, operations strategy, longitudinal research, empirical research