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In Chapter 11, first an introduction to cutting tools is presented, followed by case studies for two hard coatings. For the TiAlN PVD coating case, we describe how to adjust the formation of metastable phase, select the deposition temperature, and manipulate microstructure to obtain desired mechanical properties through first-principles calculations and thermodynamic calculations. The deposition of the TiAlN/TiN and TiAlN/ZrN multilayer guided by first-principles calculations is also briefly mentioned. For the TiCN CVD coating, we demonstrate that computed CVD phase diagrams can accurately describe phases and their compositions under the given temperature, total pressure, and pressures of various gases. Subsequently, computational fluid dynamics (CFD) is used to provide temperature field, velocity, and distributions of various gases inside the CVD reactor. From that information, calculations-designed experiments were conducted and TiCN coatings were deposited highly efficiently. These simulation-driven designs for the hard coatings have found industrial applications in just two years, much quicker compared to the costly experimental approach.
Chapter 9 focuses on superalloys operating at high temperature where high strength as well as creep and corrosion resistance are demanded. We take Ni-based single-crystal superalloys and Ni–Fe-based superalloys for advanced ultrasupercritical (A-USC) power plants as examples to demonstrate how alloy design is accomplished in these multicomponent alloy systems. The first case study introduces the design procedure of Ni-based single-crystal superalloy by using a multicriterion constrained multistart optimization algorithm. In the second case study, the design procedure of an Ni–Fe-based superalloy with the artificial neural network (ANN) model combined with a genetic algorithm (GA) based on an experimental dataset is presented.
Chapter 6 starts with a definition of thermophysical properties, followed by detailed descriptions of important terms and equations in diffusion, including Fick’s laws on diffusion; four types of diffusion coefficients (self-diffusion, impurity diffusion, intrinsic diffusion, and interdiffusion); atomic mechanisms of diffusion; diffusion equations in binary, ternary, and multicomponent phases; as well as phases with narrow homogeneity range. Short-circuit diffusion is also briefly mentioned. Subsequently, several computational methods, including first-principles calculations, MD simulation, semi-empirical approaches, and DICTRA software, are presented to calculate or estimate diffusivity and atomic mobilities from which various diffusivities can be computed. Modeling of selected important thermophysical properties, including interfacial energy, viscosity, volume, and thermal conductivity, is briefly introduced. A procedure to establish thermophysical databases is described from a materials design point of view. A case study for simulating age hardening in AA6005 Al alloys is demonstrated mainly using thermophysical properties as input to show their importance for materials design.
Chapter 12 shows strategies to design hydrogen storage materials (example LiBH4) and Li-ion batteries (example LixMn2O4 spinel cathode) through computations. The first case shows that the dehydrogenation of LiBH4 and the role of catalysts could be understood by first-principles (FP) calculations, thermodynamic modeling, and ab initio molecular dynamics simulations. CALPHAD calculations reveal phase relations and decomposition reactions for the targeted systems. Further understanding of LiBH4 decomposition is generated by FP calculations associated with formation and migration of lattice point defects. The second case aims at understanding the performance of Li-ion batteries from a comprehensive composition-structure-property relationship. The key factors (energy density, cyclability and safety) determining the performance of the battery can be evaluated by cell voltage, capacity, electrochemical stability, extent of Jahn-Teller distortion, thermodynamic stability, and extent of oxygen gas release. All these properties are obtained by combining FP calculations with CALPHAD calculations.
The basics of atomistic simulation methods, density functional theory and molecular dynamics, are first presented in Chapter 2. Then we demonstrate how to calculate some basic materials properties (including lattice parameter, thermodynamic properties, elastic properties, and defect properties) through first-principles (FP) methods. Because of the remarkable accuracy in predicting such physical and chemical properties of materials, FP is widely used in computational materials science. Finally, we take the design of Mg–Li alloys for ultralightweight application as an example to show the important role of atomistic simulation methods in material design.
The advance of human civilization with materials development from the Stone Age to the Information Age is the starting point of Chapter 1, highlighting significant roles of computational design of materials. Important terms (model, simulation, database, and materials design) used in computational materials science are defined. The past and present development of computational design of materials is then introduced. A few milestones for alloy design, such as the Hume–Rothery rule, the Phase Computation (PHACOMP) method, and the calculation of phase diagrams (CALPHAD) approach, are highlighted. The past two-decade focus on three aspects in computational design of materials (multiscale/multilevel modeling methodologies, simulation software, and scientific database) in the core of the Materials Genome Initiative is emphasized. A general framework of materials design is demonstrated with two flowcharts: through-process simulation of Al alloys during heat treatment, and the three stages for the development of engineering materials. The two-part structure of the book – fundamentals and case studies – is explained.
Chapter 13 starts with brief summary of Chapters 1–12. Subsequently, to show that the strategy described in this book is valid for design of other materials, computational designs for other four materials (Mo2BC thin film, Cu3Sn interconnect material, slag/metal/gas LD-converter steel process, and slag recycling) were highlighted. In view of the need for establishing more quantitative relationships among four cornerstones (composition/processing-structure–properties–performance) in materials science and engineering as well as advancing product design methods, several future orientations and challenges for computational design of engineering materials are suggested. These are (1) advancement of models and approaches for more quantitative simulation in materials design, such as interfacial thermodynamics, thermodynamics under external fields, and a more quantitative phase-field model; (2) the need for scientific databases and materials informatics; (3) enhanced simulation software packages; and (4) concurrent design of materials and products (CDMP). Finally, the correlations among ICME, MGI, and CDMP are discussed.
In Chapter 4, firstly a few basic terms (object and configuration, stress, strain, and constitutive relation between stress tensor and strain tensor), three coordinate systems (shape coordinate, lattice coordinate, and laboratory coordinate), deformation gradient as well as fundamental equations in continuum mechanics are briefly recalled for the sake of understanding fundamental equations of the crystal plasticity finite element method (CPFEM). A few advantages of CPFEM (including its abilities to analyze multiparticle problems and solve crystal mechanics problems with complex boundary conditions) are highlighted. Then, representative mechanical constitutive laws of crystal plasticity including dislocation-based constitutive models and constitutive models for displacive transformation are briefly described, followed by a short introduction to the finite element method (FEM), several FEM software packages (including Adina, ABAQUS, Deform, and ANSYS) and a procedure for CPFEM simulation. Finally, a case study of plastic deformation-induced surface roughening in Al polycrystals is demonstrated to show important features of crystal plasticity finite element method in materials design.
Chapter 7 briefly introduces steels, including classification, production processes, microstructure, and properties as well as computational tools for design of steels. Two case studies for S53 and AISI H13 steels are demonstrated. For S53 steel, high strength and good corrosion resistance are needed. For that purpose, plots of thermodynamic driving forces for precipitates were established, guaranteeing the accurate precipitation of M2C strengthener in steels. In addition, a martensite model is developed, designing maximal strengthening effect and appropriate martensite start temperature to maintain an alloy with lath martensite as the matrix. The corrosion resistance was designed by analyzing thermodynamic effects to maximize Cr partitioning in spinel oxide and enhance the grain boundary cohesion. In the case of AISI H13 steel, precipitations of carbides were simulated. Then simulated microstructure was coupled with structure–property models to predict the stress–strain curve and creep properties. Subsequently, those simulated properties were coupled with FEM to predict the relaxation of internal stresses and deformation behavior at the macroscopic scale during tempering of AISI H13
Test anxiety refers to maladaptive cognitive and physiological reactions that interfere with optimal performance. Self-regulatory models suggest test anxiety occurs when there is a perceived discrepancy between current functioning and mental representations of desired academic goals. Interestingly, prior investigations have demonstrated those with greater interhemispheric communication are better able to detect discrepancies between current functioning and preexisting mental representations. Thus, the current study was designed to investigate the relationship between test anxiety and handedness—a commonly used proxy variable for interhemispheric communication. Undergraduate and graduate students (N = 277, 85.20% female, 68.19% Caucasian, $ \overline{\chi} $age = 29.88) (SD = 9.53) completed the FRIEDBEN Test Anxiety Scale and Edinburgh Handedness Inventory – Short Form. A series of Mann–Whitney U tests were used to test for differences in the cognitive, physiological, and social components of test anxiety between mixed- and consistent-handers. The results indicated that mixed-handers had significantly higher levels of cognitive test anxiety than consistent-handers. We believe this information has important implications for our understanding of the role of discrepancy detection and interhemispheric communication in eliciting and maintaining test-anxious responses.
Liquid crystal elastomers (LCEs) are programmable materials par excellence. I review the history and state of the art of LCE materials and processing development from the perspective of the important remaining step of moving out of the academic research lab and applying LCEs as soft actuators or strain sensors. After a brief introduction for the non-expert of what LCEs are and which their main advantages and limitations are, I discuss the key breakthroughs that LCE research has undergone over its 50-year history. Building on this and drawing from fresh results from on-going research, I consider possible future development trajectories that would help address the outstanding key obstacles to reach mass production at competitive cost. I end with discussing a selected set of application scenarios with good opportunities for LCEs to perform functions that no other material could deliver. Specifically, I focus on responsive buildings incorporating LCE actuator fibres and sheets/ribbons, structural health monitoring with LCE strain sensors monitoring crack growth and propagation or alerting residents of buildings exposed to dangerous levels of deformation, and kinetic and responsive garments incorporating LCE fibre actuators and/or strain sensors.
Biodesign is a recent discipline broad in scale and scope, reaching towards solving complex ecological issues such as climate breakdown, pollution, biodiversity loss and social justice. Designers manipulate living matter and translate scientific discoveries and methods into real-world applications. Although some specialization and knowledge have emerged from working with specific organisms like algae, mycelium, bacteria, for example, the variety and vastness of the natural sciences require a greater understanding of the intricacies of the collaborative nature and interrelationships between lab protocols, scientific tools and methods and the tools and techniques for design production. As a result, the ingenuity of biodesigners to adapt, transform and invent new interdisciplinary methods is an emerging space. We are looking at presenting and discussing the invention of new technical skills, toolkits and machines that allow for the calibration and manipulation of living systems for the the advancement of the discipline of Biodesign.
Yield decline has been the hallmark of Ethiopian sugarcane plantations. However, the extent and causes of the decline have not yet been empirically studied, making it difficult to manage the problem. This study aimed at analyzing the long-term yield data (1954–2022) with respect to variety and soil type. Thus, 8,923 records of yield data were summarized and sorted into decades, varieties, and soil types and then analyzed by applying Mann-Kendall and Tukey’s tests. The fields were classified and mapped using ArcGIS 10.3. The results revealed that 69% of the plantation fields were classified as “yield declining,” and the overall rate of decline has been 8.4 quintals ha−1 year−1 (R2 = 0.76). The rate of decline was higher for older than newer varieties and for vertisols than cambiols. Therefore, the older varieties should be micropropagated or replaced with improved ones, and the vertisols should be amended through practices such as green manuring, improved fallows, etc.
The crystal structure of 5-(3-methoxyphenyl)indoline-2,3-dione (C15H11NO3) was solved and refined using laboratory powder diffraction data and optimized using density functional techniques. The title compound crystallizes in space group Pbca with a = 11.1772(3) Å, b = 7.92536(13) Å, c = 27.0121(7) Å, and V = 2392.82(10) Å3. The asymmetric unit contains one molecule. Isatin molecules are joined into almost flat chains along the a direction by N–H⋯O bonds. The chains are linked into layers by π-stacking interactions. Finally, the third dimension of the crystal is formed by weaker C–H⋯π and C–H⋯O contacts.