Author: Buntara Gan
Publisher: CRC Press
ISBN: 0429680708
Category : Technology & Engineering
Languages : en
Pages : 276
Book Description
Condensed Isogeometric Analysis for Plates and Shell Structures proposes a novel technique for plate and shell governing equations based on isogeometric analysis, which condenses the dynamic equilibrium equation for plate and shell structures—suitable for reducing the computation cost of large degrees of freedom due to the adoption of Non-Uniform Rational Basis Spline (NURBS) models in the plate and shell element formulations. It features useful guidance for understanding the isogeometric approach and includes accompanying MATLAB® source code in each chapter to deepen readers' understanding of the fundamental theories and methods of civil, architectural, and mechanical engineering. Features: Adopts a progressive and rigorous presentation of relevant topics to facilitate use by students, academics, and professionals Seamlessly integrates the CAD geometrical data into the conventional FE plate and shell classical element codes Allows computation of analytical solutions of plate and shell theories based on a newly-introduced condensation method, not approximation theory Includes relevant MATLAB® codes
Condensed Isogeometric Analysis for Plate and Shell Structures
Author: Buntara Gan
Publisher: CRC Press
ISBN: 0429680708
Category : Technology & Engineering
Languages : en
Pages : 276
Book Description
Condensed Isogeometric Analysis for Plates and Shell Structures proposes a novel technique for plate and shell governing equations based on isogeometric analysis, which condenses the dynamic equilibrium equation for plate and shell structures—suitable for reducing the computation cost of large degrees of freedom due to the adoption of Non-Uniform Rational Basis Spline (NURBS) models in the plate and shell element formulations. It features useful guidance for understanding the isogeometric approach and includes accompanying MATLAB® source code in each chapter to deepen readers' understanding of the fundamental theories and methods of civil, architectural, and mechanical engineering. Features: Adopts a progressive and rigorous presentation of relevant topics to facilitate use by students, academics, and professionals Seamlessly integrates the CAD geometrical data into the conventional FE plate and shell classical element codes Allows computation of analytical solutions of plate and shell theories based on a newly-introduced condensation method, not approximation theory Includes relevant MATLAB® codes
Publisher: CRC Press
ISBN: 0429680708
Category : Technology & Engineering
Languages : en
Pages : 276
Book Description
Condensed Isogeometric Analysis for Plates and Shell Structures proposes a novel technique for plate and shell governing equations based on isogeometric analysis, which condenses the dynamic equilibrium equation for plate and shell structures—suitable for reducing the computation cost of large degrees of freedom due to the adoption of Non-Uniform Rational Basis Spline (NURBS) models in the plate and shell element formulations. It features useful guidance for understanding the isogeometric approach and includes accompanying MATLAB® source code in each chapter to deepen readers' understanding of the fundamental theories and methods of civil, architectural, and mechanical engineering. Features: Adopts a progressive and rigorous presentation of relevant topics to facilitate use by students, academics, and professionals Seamlessly integrates the CAD geometrical data into the conventional FE plate and shell classical element codes Allows computation of analytical solutions of plate and shell theories based on a newly-introduced condensation method, not approximation theory Includes relevant MATLAB® codes
Condensed Isogeometric Analysis for Plate and Shell Structures
Author: Buntara Gan
Publisher: CRC Press
ISBN: 0429680694
Category : Technology & Engineering
Languages : en
Pages : 242
Book Description
Condensed Isogeometric Analysis for Plates and Shell Structures proposes a novel technique for plate and shell governing equations based on isogeometric analysis, which condenses the dynamic equilibrium equation for plate and shell structures—suitable for reducing the computation cost of large degrees of freedom due to the adoption of Non-Uniform Rational Basis Spline (NURBS) models in the plate and shell element formulations. It features useful guidance for understanding the isogeometric approach and includes accompanying MATLAB® source code in each chapter to deepen readers' understanding of the fundamental theories and methods of civil, architectural, and mechanical engineering. Features: Adopts a progressive and rigorous presentation of relevant topics to facilitate use by students, academics, and professionals Seamlessly integrates the CAD geometrical data into the conventional FE plate and shell classical element codes Allows computation of analytical solutions of plate and shell theories based on a newly-introduced condensation method, not approximation theory Includes relevant MATLAB® codes
Publisher: CRC Press
ISBN: 0429680694
Category : Technology & Engineering
Languages : en
Pages : 242
Book Description
Condensed Isogeometric Analysis for Plates and Shell Structures proposes a novel technique for plate and shell governing equations based on isogeometric analysis, which condenses the dynamic equilibrium equation for plate and shell structures—suitable for reducing the computation cost of large degrees of freedom due to the adoption of Non-Uniform Rational Basis Spline (NURBS) models in the plate and shell element formulations. It features useful guidance for understanding the isogeometric approach and includes accompanying MATLAB® source code in each chapter to deepen readers' understanding of the fundamental theories and methods of civil, architectural, and mechanical engineering. Features: Adopts a progressive and rigorous presentation of relevant topics to facilitate use by students, academics, and professionals Seamlessly integrates the CAD geometrical data into the conventional FE plate and shell classical element codes Allows computation of analytical solutions of plate and shell theories based on a newly-introduced condensation method, not approximation theory Includes relevant MATLAB® codes
Anisotropic Doubly-Curved Shells
Author: Francesco Tornabene
Publisher: Società Editrice Esculapio
ISBN: 8835328993
Category : Technology & Engineering
Languages : en
Pages : 1199
Book Description
This book aims to present in depth several Higher-order Shear Deformation Theories (HSDTs) by means of a unified approach for the mechanical analysis of doubly-curved shell structures made of anisotropic and composite materials. In particular, the strong and weak formulations of the corresponding governing equations are discussed and illustrated. The approach presented in this volume is completely general and represents a valid tool to investigate the structural behavior of many arbitrarily shaped structures. An isogeometric mapping procedure is also illustrated to this aim. Special attention is given also to advanced and innovative constituents, such as Carbon Nanotubes (CNTs), Variable Angle Tow (VAT) composites and Functionally Graded Materials (FGMs). In addition, several numerical applications are developed to support the theoretical models. Accurate, efficient and reliable numerical techniques able to approximate both derivatives and integrals are presented, which are respectively the Differential Quadrature (DQ) and Integral Quadrature (IQ) methods. Finally, two numerical techniques, named Strong Formulation Finite Element Method (SFEM) and Weak Formulation Finite Element Method (WFEM), are developed to deal with multi-element domains characterized by arbitrary shapes and discontinuities.
Publisher: Società Editrice Esculapio
ISBN: 8835328993
Category : Technology & Engineering
Languages : en
Pages : 1199
Book Description
This book aims to present in depth several Higher-order Shear Deformation Theories (HSDTs) by means of a unified approach for the mechanical analysis of doubly-curved shell structures made of anisotropic and composite materials. In particular, the strong and weak formulations of the corresponding governing equations are discussed and illustrated. The approach presented in this volume is completely general and represents a valid tool to investigate the structural behavior of many arbitrarily shaped structures. An isogeometric mapping procedure is also illustrated to this aim. Special attention is given also to advanced and innovative constituents, such as Carbon Nanotubes (CNTs), Variable Angle Tow (VAT) composites and Functionally Graded Materials (FGMs). In addition, several numerical applications are developed to support the theoretical models. Accurate, efficient and reliable numerical techniques able to approximate both derivatives and integrals are presented, which are respectively the Differential Quadrature (DQ) and Integral Quadrature (IQ) methods. Finally, two numerical techniques, named Strong Formulation Finite Element Method (SFEM) and Weak Formulation Finite Element Method (WFEM), are developed to deal with multi-element domains characterized by arbitrary shapes and discontinuities.
Finite Elements in Structural Analysis
Author: Horst Werkle
Publisher: Springer Nature
ISBN: 3030498409
Category : Science
Languages : en
Pages : 709
Book Description
The book introduces the basic concepts of the finite element method in the static and dynamic analysis of beam, plate, shell and solid structures, discussing how the method works, the characteristics of a finite element approximation and how to avoid the pitfalls of finite element modeling. Presenting the finite element theory as simply as possible, the book allows readers to gain the knowledge required when applying powerful FEA software tools. Further, it describes modeling procedures, especially for reinforced concrete structures, as well as structural dynamics methods, with a particular focus on the seismic analysis of buildings, and explores the modeling of dynamic systems. Featuring numerous illustrative examples, the book allows readers to easily grasp the fundamentals of the finite element theory and to apply the finite element method proficiently.
Publisher: Springer Nature
ISBN: 3030498409
Category : Science
Languages : en
Pages : 709
Book Description
The book introduces the basic concepts of the finite element method in the static and dynamic analysis of beam, plate, shell and solid structures, discussing how the method works, the characteristics of a finite element approximation and how to avoid the pitfalls of finite element modeling. Presenting the finite element theory as simply as possible, the book allows readers to gain the knowledge required when applying powerful FEA software tools. Further, it describes modeling procedures, especially for reinforced concrete structures, as well as structural dynamics methods, with a particular focus on the seismic analysis of buildings, and explores the modeling of dynamic systems. Featuring numerous illustrative examples, the book allows readers to easily grasp the fundamentals of the finite element theory and to apply the finite element method proficiently.
Nonlinear Finite Element Analysis of Solids and Structures
Author: René de Borst
Publisher: John Wiley & Sons
ISBN: 1118376013
Category : Technology & Engineering
Languages : en
Pages : 481
Book Description
Built upon the two original books by Mike Crisfield and their own lecture notes, renowned scientist René de Borst and his team offer a thoroughly updated yet condensed edition that retains and builds upon the excellent reputation and appeal amongst students and engineers alike for which Crisfield's first edition is acclaimed. Together with numerous additions and updates, the new authors have retained the core content of the original publication, while bringing an improved focus on new developments and ideas. This edition offers the latest insights in non-linear finite element technology, including non-linear solution strategies, computational plasticity, damage mechanics, time-dependent effects, hyperelasticity and large-strain elasto-plasticity. The authors' integrated and consistent style and unrivalled engineering approach assures this book's unique position within the computational mechanics literature. Key features: Combines the two previous volumes into one heavily revised text with obsolete material removed, an improved layout and updated references and notations Extensive new material on more recent developments in computational mechanics Easily readable, engineering oriented, with no more details in the main text than necessary to understand the concepts. Pseudo-code throughout makes the link between theory and algorithms, and the actual implementation. Accompanied by a website (www.wiley.com/go/deborst) with a Python code, based on the pseudo-code within the book and suitable for solving small-size problems. Non-linear Finite Element Analysis of Solids and Structures, 2nd Edition is an essential reference for practising engineers and researchers that can also be used as a text for undergraduate and graduate students within computational mechanics.
Publisher: John Wiley & Sons
ISBN: 1118376013
Category : Technology & Engineering
Languages : en
Pages : 481
Book Description
Built upon the two original books by Mike Crisfield and their own lecture notes, renowned scientist René de Borst and his team offer a thoroughly updated yet condensed edition that retains and builds upon the excellent reputation and appeal amongst students and engineers alike for which Crisfield's first edition is acclaimed. Together with numerous additions and updates, the new authors have retained the core content of the original publication, while bringing an improved focus on new developments and ideas. This edition offers the latest insights in non-linear finite element technology, including non-linear solution strategies, computational plasticity, damage mechanics, time-dependent effects, hyperelasticity and large-strain elasto-plasticity. The authors' integrated and consistent style and unrivalled engineering approach assures this book's unique position within the computational mechanics literature. Key features: Combines the two previous volumes into one heavily revised text with obsolete material removed, an improved layout and updated references and notations Extensive new material on more recent developments in computational mechanics Easily readable, engineering oriented, with no more details in the main text than necessary to understand the concepts. Pseudo-code throughout makes the link between theory and algorithms, and the actual implementation. Accompanied by a website (www.wiley.com/go/deborst) with a Python code, based on the pseudo-code within the book and suitable for solving small-size problems. Non-linear Finite Element Analysis of Solids and Structures, 2nd Edition is an essential reference for practising engineers and researchers that can also be used as a text for undergraduate and graduate students within computational mechanics.
The NURBS Book
Author: Les Piegl
Publisher: Springer Science & Business Media
ISBN: 3642592236
Category : Computers
Languages : en
Pages : 650
Book Description
Until recently B-spline curves and surfaces (NURBS) were principally of interest to the computer aided design community, where they have become the standard for curve and surface description. Today we are seeing expanded use of NURBS in modeling objects for the visual arts, including the film and entertainment industries, art, and sculpture. NURBS are now also being used for modeling scenes for virtual reality applications. These applications are expected to increase. Consequently, it is quite appropriate for The.N'URBS Book to be part of the Monographs in Visual Communication Series. B-spline curves and surfaces have been an enduring element throughout my pro fessional life. The first edition of Mathematical Elements for Computer Graphics, published in 1972, was the first computer aided design/interactive computer graph ics textbook to contain material on B-splines. That material was obtained through the good graces of Bill Gordon and Louie Knapp while they were at Syracuse University. A paper of mine, presented during the Summer of 1977 at a Society of Naval Architects and Marine Engineers meeting on computer aided ship surface design, was arguably the first to examine the use of B-spline curves for ship design. For many, B-splines, rational B-splines, and NURBS have been a bit mysterious.
Publisher: Springer Science & Business Media
ISBN: 3642592236
Category : Computers
Languages : en
Pages : 650
Book Description
Until recently B-spline curves and surfaces (NURBS) were principally of interest to the computer aided design community, where they have become the standard for curve and surface description. Today we are seeing expanded use of NURBS in modeling objects for the visual arts, including the film and entertainment industries, art, and sculpture. NURBS are now also being used for modeling scenes for virtual reality applications. These applications are expected to increase. Consequently, it is quite appropriate for The.N'URBS Book to be part of the Monographs in Visual Communication Series. B-spline curves and surfaces have been an enduring element throughout my pro fessional life. The first edition of Mathematical Elements for Computer Graphics, published in 1972, was the first computer aided design/interactive computer graph ics textbook to contain material on B-splines. That material was obtained through the good graces of Bill Gordon and Louie Knapp while they were at Syracuse University. A paper of mine, presented during the Summer of 1977 at a Society of Naval Architects and Marine Engineers meeting on computer aided ship surface design, was arguably the first to examine the use of B-spline curves for ship design. For many, B-splines, rational B-splines, and NURBS have been a bit mysterious.
Encyclopedia of Continuum Mechanics
Author: Holm Altenbach
Publisher: Springer
ISBN: 9783662557709
Category : Science
Languages : en
Pages : 0
Book Description
This Encyclopedia covers the entire science of continuum mechanics including the mechanics of materials and fluids. The encyclopedia comprises mathematical definitions for continuum mechanical modeling, fundamental physical concepts, mechanical modeling methodology, numerical approaches and many fundamental applications. The modelling and analytical techniques are powerful tools in mechanical civil and areospsace engineering, plus in related fields of plasticity, viscoelasticity and rheology. Tensor-based and reference-frame-independent, continuum mechanics has recently found applications in geophysics and materials.
Publisher: Springer
ISBN: 9783662557709
Category : Science
Languages : en
Pages : 0
Book Description
This Encyclopedia covers the entire science of continuum mechanics including the mechanics of materials and fluids. The encyclopedia comprises mathematical definitions for continuum mechanical modeling, fundamental physical concepts, mechanical modeling methodology, numerical approaches and many fundamental applications. The modelling and analytical techniques are powerful tools in mechanical civil and areospsace engineering, plus in related fields of plasticity, viscoelasticity and rheology. Tensor-based and reference-frame-independent, continuum mechanics has recently found applications in geophysics and materials.
Structural Analysis with the Finite Element Method. Linear Statics
Author: Eugenio Oñate
Publisher: Springer Science & Business Media
ISBN: 1402087438
Category : Technology & Engineering
Languages : en
Pages : 894
Book Description
STRUCTURAL ANALYSIS WITH THE FINITE ELEMENT METHOD Linear Statics Volume 1 : The Basis and Solids Eugenio Oñate The two volumes of this book cover most of the theoretical and computational aspects of the linear static analysis of structures with the Finite Element Method (FEM). The content of the book is based on the lecture notes of a basic course on Structural Analysis with the FEM taught by the author at the Technical University of Catalonia (UPC) in Barcelona, Spain for the last 30 years. Volume1 presents the basis of the FEM for structural analysis and a detailed description of the finite element formulation for axially loaded bars, plane elasticity problems, axisymmetric solids and general three dimensional solids. Each chapter describes the background theory for each structural model considered, details of the finite element formulation and guidelines for the application to structural engineering problems. The book includes a chapter on miscellaneous topics such as treatment of inclined supports, elastic foundations, stress smoothing, error estimation and adaptive mesh refinement techniques, among others. The text concludes with a chapter on the mesh generation and visualization of FEM results. The book will be useful for students approaching the finite element analysis of structures for the first time, as well as for practising engineers interested in the details of the formulation and performance of the different finite elements for practical structural analysis. STRUCTURAL ANALYSIS WITH THE FINITE ELEMENT METHOD Linear Statics Volume 2: Beams, Plates and Shells Eugenio Oñate The two volumes of this book cover most of the theoretical and computational aspects of the linear static analysis of structures with the Finite Element Method (FEM).The content of the book is based on the lecture notes of a basic course on Structural Analysis with the FEM taught by the author at the Technical University of Catalonia (UPC) in Barcelona, Spain for the last 30 years. Volume 2 presents a detailed description of the finite element formulation for analysis of slender and thick beams, thin and thick plates, folded plate structures, axisymmetric shells, general curved shells, prismatic structures and three dimensional beams. Each chapter describes the background theory for each structural model considered, details of the finite element formulation and guidelines for the application to structural engineering problems Emphasis is put on the treatment of structures with layered composite materials. The book will be useful for students approaching the finite element analysis of beam, plate and shell structures for the first time, as well as for practising engineers interested in the details of the formulation and performance of the different finite elements for practical structural analysis.
Publisher: Springer Science & Business Media
ISBN: 1402087438
Category : Technology & Engineering
Languages : en
Pages : 894
Book Description
STRUCTURAL ANALYSIS WITH THE FINITE ELEMENT METHOD Linear Statics Volume 1 : The Basis and Solids Eugenio Oñate The two volumes of this book cover most of the theoretical and computational aspects of the linear static analysis of structures with the Finite Element Method (FEM). The content of the book is based on the lecture notes of a basic course on Structural Analysis with the FEM taught by the author at the Technical University of Catalonia (UPC) in Barcelona, Spain for the last 30 years. Volume1 presents the basis of the FEM for structural analysis and a detailed description of the finite element formulation for axially loaded bars, plane elasticity problems, axisymmetric solids and general three dimensional solids. Each chapter describes the background theory for each structural model considered, details of the finite element formulation and guidelines for the application to structural engineering problems. The book includes a chapter on miscellaneous topics such as treatment of inclined supports, elastic foundations, stress smoothing, error estimation and adaptive mesh refinement techniques, among others. The text concludes with a chapter on the mesh generation and visualization of FEM results. The book will be useful for students approaching the finite element analysis of structures for the first time, as well as for practising engineers interested in the details of the formulation and performance of the different finite elements for practical structural analysis. STRUCTURAL ANALYSIS WITH THE FINITE ELEMENT METHOD Linear Statics Volume 2: Beams, Plates and Shells Eugenio Oñate The two volumes of this book cover most of the theoretical and computational aspects of the linear static analysis of structures with the Finite Element Method (FEM).The content of the book is based on the lecture notes of a basic course on Structural Analysis with the FEM taught by the author at the Technical University of Catalonia (UPC) in Barcelona, Spain for the last 30 years. Volume 2 presents a detailed description of the finite element formulation for analysis of slender and thick beams, thin and thick plates, folded plate structures, axisymmetric shells, general curved shells, prismatic structures and three dimensional beams. Each chapter describes the background theory for each structural model considered, details of the finite element formulation and guidelines for the application to structural engineering problems Emphasis is put on the treatment of structures with layered composite materials. The book will be useful for students approaching the finite element analysis of beam, plate and shell structures for the first time, as well as for practising engineers interested in the details of the formulation and performance of the different finite elements for practical structural analysis.
Advances in Applied Mechanical Engineering
Author: Hari Kumar Voruganti
Publisher: Springer Nature
ISBN: 9811512019
Category : Science
Languages : en
Pages : 1161
Book Description
This book presents select peer reviewed proceedings of the International Conference on Applied Mechanical Engineering Research (ICAMER 2019). The books examines various areas of mechanical engineering namely design, thermal, materials, manufacturing and industrial engineering covering topics like FEA, optimization, vibrations, condition monitoring, tribology, CFD, IC engines, turbo-machines, automobiles, manufacturing processes, machining, CAM, additive manufacturing, modelling and simulation of manufacturing processing, optimization of manufacturing processing, supply chain management, and operations management. In addition, recent studies on composite materials, materials characterization, fracture and fatigue, advanced materials, energy storage, green building, phase change materials and structural change monitoring are also covered. Given the contents, this book will be useful for students, researchers and professionals working in mechanical engineering and allied fields.
Publisher: Springer Nature
ISBN: 9811512019
Category : Science
Languages : en
Pages : 1161
Book Description
This book presents select peer reviewed proceedings of the International Conference on Applied Mechanical Engineering Research (ICAMER 2019). The books examines various areas of mechanical engineering namely design, thermal, materials, manufacturing and industrial engineering covering topics like FEA, optimization, vibrations, condition monitoring, tribology, CFD, IC engines, turbo-machines, automobiles, manufacturing processes, machining, CAM, additive manufacturing, modelling and simulation of manufacturing processing, optimization of manufacturing processing, supply chain management, and operations management. In addition, recent studies on composite materials, materials characterization, fracture and fatigue, advanced materials, energy storage, green building, phase change materials and structural change monitoring are also covered. Given the contents, this book will be useful for students, researchers and professionals working in mechanical engineering and allied fields.
The Scaled Boundary Finite Element Method
Author: Chongmin Song
Publisher: John Wiley & Sons
ISBN: 1119388457
Category : Science
Languages : en
Pages : 775
Book Description
An informative look at the theory, computer implementation, and application of the scaled boundary finite element method This reliable resource, complete with MATLAB, is an easy-to-understand introduction to the fundamental principles of the scaled boundary finite element method. It establishes the theory of the scaled boundary finite element method systematically as a general numerical procedure, providing the reader with a sound knowledge to expand the applications of this method to a broader scope. The book also presents the applications of the scaled boundary finite element to illustrate its salient features and potentials. The Scaled Boundary Finite Element Method: Introduction to Theory and Implementation covers the static and dynamic stress analysis of solids in two and three dimensions. The relevant concepts, theory and modelling issues of the scaled boundary finite element method are discussed and the unique features of the method are highlighted. The applications in computational fracture mechanics are detailed with numerical examples. A unified mesh generation procedure based on quadtree/octree algorithm is described. It also presents examples of fully automatic stress analysis of geometric models in NURBS, STL and digital images. Written in lucid and easy to understand language by the co-inventor of the scaled boundary element method Provides MATLAB as an integral part of the book with the code cross-referenced in the text and the use of the code illustrated by examples Presents new developments in the scaled boundary finite element method with illustrative examples so that readers can appreciate the significant features and potentials of this novel method—especially in emerging technologies such as 3D printing, virtual reality, and digital image-based analysis The Scaled Boundary Finite Element Method: Introduction to Theory and Implementation is an ideal book for researchers, software developers, numerical analysts, and postgraduate students in many fields of engineering and science.
Publisher: John Wiley & Sons
ISBN: 1119388457
Category : Science
Languages : en
Pages : 775
Book Description
An informative look at the theory, computer implementation, and application of the scaled boundary finite element method This reliable resource, complete with MATLAB, is an easy-to-understand introduction to the fundamental principles of the scaled boundary finite element method. It establishes the theory of the scaled boundary finite element method systematically as a general numerical procedure, providing the reader with a sound knowledge to expand the applications of this method to a broader scope. The book also presents the applications of the scaled boundary finite element to illustrate its salient features and potentials. The Scaled Boundary Finite Element Method: Introduction to Theory and Implementation covers the static and dynamic stress analysis of solids in two and three dimensions. The relevant concepts, theory and modelling issues of the scaled boundary finite element method are discussed and the unique features of the method are highlighted. The applications in computational fracture mechanics are detailed with numerical examples. A unified mesh generation procedure based on quadtree/octree algorithm is described. It also presents examples of fully automatic stress analysis of geometric models in NURBS, STL and digital images. Written in lucid and easy to understand language by the co-inventor of the scaled boundary element method Provides MATLAB as an integral part of the book with the code cross-referenced in the text and the use of the code illustrated by examples Presents new developments in the scaled boundary finite element method with illustrative examples so that readers can appreciate the significant features and potentials of this novel method—especially in emerging technologies such as 3D printing, virtual reality, and digital image-based analysis The Scaled Boundary Finite Element Method: Introduction to Theory and Implementation is an ideal book for researchers, software developers, numerical analysts, and postgraduate students in many fields of engineering and science.