Author: Milan Paunovic
Publisher: John Wiley & Sons
ISBN: 047000939X
Category : Science
Languages : en
Pages : 388
Book Description
Excellent teaching and resource material . . . it is concise, coherently structured, and easy to read . . . highly recommended for students, engineers, and researchers in all related fields." -Corrosion on the First Edition of Fundamentals of Electrochemical Deposition From computer hardware to automobiles, medical diagnostics to aerospace, electrochemical deposition plays a crucial role in an array of key industries. Fundamentals of Electrochemical Deposition, Second Edition is a comprehensive introduction to one of today's most exciting and rapidly evolving fields of practical knowledge. The most authoritative introduction to the field so far, the book presents detailed coverage of the full range of electrochemical deposition processes and technologies, including: * Metal-solution interphase * Charge transfer across an interphase * Formation of an equilibrium electrode potential * Nucleation and growth of thin films * Kinetics and mechanisms of electrodeposition * Electroless deposition * In situ characterization of deposition processes * Structure and properties of deposits * Multilayered and composite thin films * Interdiffusion in thin film * Applications in the semiconductor industry and the field of medicine This new edition updates the prior edition to address the new developments in the science and its applications, with new chapters on innovative applications of electrochemical deposition in semiconductor technology, magnetism and microelectronics, and medical instrumentation. Added coverage includes such topics as binding energy, nanoclusters, atomic force, and scanning tunneling microscopy.Example problems at the end of chapters and other features clarify and improve understanding of the material. Written by an author team with extensive experience in both industry and academe, this reference and text provides a well-rounded introduction to the field for students, as well as a means for professional chemists, engineers, and technicians to expand and sharpen their skills in using the technology.
Fundamentals of Electrochemical Deposition
Author: Milan Paunovic
Publisher: John Wiley & Sons
ISBN: 047000939X
Category : Science
Languages : en
Pages : 388
Book Description
Excellent teaching and resource material . . . it is concise, coherently structured, and easy to read . . . highly recommended for students, engineers, and researchers in all related fields." -Corrosion on the First Edition of Fundamentals of Electrochemical Deposition From computer hardware to automobiles, medical diagnostics to aerospace, electrochemical deposition plays a crucial role in an array of key industries. Fundamentals of Electrochemical Deposition, Second Edition is a comprehensive introduction to one of today's most exciting and rapidly evolving fields of practical knowledge. The most authoritative introduction to the field so far, the book presents detailed coverage of the full range of electrochemical deposition processes and technologies, including: * Metal-solution interphase * Charge transfer across an interphase * Formation of an equilibrium electrode potential * Nucleation and growth of thin films * Kinetics and mechanisms of electrodeposition * Electroless deposition * In situ characterization of deposition processes * Structure and properties of deposits * Multilayered and composite thin films * Interdiffusion in thin film * Applications in the semiconductor industry and the field of medicine This new edition updates the prior edition to address the new developments in the science and its applications, with new chapters on innovative applications of electrochemical deposition in semiconductor technology, magnetism and microelectronics, and medical instrumentation. Added coverage includes such topics as binding energy, nanoclusters, atomic force, and scanning tunneling microscopy.Example problems at the end of chapters and other features clarify and improve understanding of the material. Written by an author team with extensive experience in both industry and academe, this reference and text provides a well-rounded introduction to the field for students, as well as a means for professional chemists, engineers, and technicians to expand and sharpen their skills in using the technology.
Publisher: John Wiley & Sons
ISBN: 047000939X
Category : Science
Languages : en
Pages : 388
Book Description
Excellent teaching and resource material . . . it is concise, coherently structured, and easy to read . . . highly recommended for students, engineers, and researchers in all related fields." -Corrosion on the First Edition of Fundamentals of Electrochemical Deposition From computer hardware to automobiles, medical diagnostics to aerospace, electrochemical deposition plays a crucial role in an array of key industries. Fundamentals of Electrochemical Deposition, Second Edition is a comprehensive introduction to one of today's most exciting and rapidly evolving fields of practical knowledge. The most authoritative introduction to the field so far, the book presents detailed coverage of the full range of electrochemical deposition processes and technologies, including: * Metal-solution interphase * Charge transfer across an interphase * Formation of an equilibrium electrode potential * Nucleation and growth of thin films * Kinetics and mechanisms of electrodeposition * Electroless deposition * In situ characterization of deposition processes * Structure and properties of deposits * Multilayered and composite thin films * Interdiffusion in thin film * Applications in the semiconductor industry and the field of medicine This new edition updates the prior edition to address the new developments in the science and its applications, with new chapters on innovative applications of electrochemical deposition in semiconductor technology, magnetism and microelectronics, and medical instrumentation. Added coverage includes such topics as binding energy, nanoclusters, atomic force, and scanning tunneling microscopy.Example problems at the end of chapters and other features clarify and improve understanding of the material. Written by an author team with extensive experience in both industry and academe, this reference and text provides a well-rounded introduction to the field for students, as well as a means for professional chemists, engineers, and technicians to expand and sharpen their skills in using the technology.
Fundamentals of Electrochemical Growth and Surface Limited Deposition
Author: S. Brankovic
Publisher: The Electrochemical Society
ISBN: 160768697X
Category : Science
Languages : en
Pages : 23
Book Description
Publisher: The Electrochemical Society
ISBN: 160768697X
Category : Science
Languages : en
Pages : 23
Book Description
Electrochemical Phase Formation and Growth
Author: Evgeni B. Budevski
Publisher: John Wiley & Sons
ISBN: 3527614923
Category : Science
Languages : en
Pages : 421
Book Description
Electrochemical processes and methods are basic to many important scientific disciplines, materials science and nanotechnology being only two keywords. For the first time in more than twenty years this volume presents a critical survey of the foundations, methodology and applications of electrochemical phase formation and growth processes. Written by a team of three internationally renowned authors, it is an invaluable source of information for all scientists concerned with electrocrystallization of metals or the in-situ characterization of electron-conducting surfaces. Not only the numerous illustrations (partly in colour) but also the vast number of references covering the literature up to and including 1995 make this volume indispensable for every laboratory working in electrochemical or materials science.
Publisher: John Wiley & Sons
ISBN: 3527614923
Category : Science
Languages : en
Pages : 421
Book Description
Electrochemical processes and methods are basic to many important scientific disciplines, materials science and nanotechnology being only two keywords. For the first time in more than twenty years this volume presents a critical survey of the foundations, methodology and applications of electrochemical phase formation and growth processes. Written by a team of three internationally renowned authors, it is an invaluable source of information for all scientists concerned with electrocrystallization of metals or the in-situ characterization of electron-conducting surfaces. Not only the numerous illustrations (partly in colour) but also the vast number of references covering the literature up to and including 1995 make this volume indispensable for every laboratory working in electrochemical or materials science.
Electrocrystallization
Author: Alexander Milchev
Publisher: Springer Science & Business Media
ISBN: 0306475529
Category : Science
Languages : en
Pages : 274
Book Description
“Electrocrystallization is a particular case of a first order phase transition” and “Electrocrystallization is a particular case of electrochemical kinetics” are two statements that I have heard and read many times. I do not like them for a simple reason: it is annoying to see that the subject to which you have devoted more than 30 years of your life may be considered as a “particular case”. Therefore, I decided to write this book in which Electrocrystallization is the main subject. To become competent in the field of Electrocrystallization one should possess knowledge of Electrochemistry, Nucleation and Crystal Growth, which means knowledge of Physical Chemistry, Physics and Mathematics. That is certainly difficult and in most cases those who study Electrocrystallization are either more electrochemists, or more physical chemists, or more physicists, very often depending on whom has been their teacher. Of course, there are scientists who consider themselves equally good in all those fields. Very frequently they are, unfortunately, equally bad. The difference is essential but strange enough, it is sometimes not easy to realize the truth immediately.
Publisher: Springer Science & Business Media
ISBN: 0306475529
Category : Science
Languages : en
Pages : 274
Book Description
“Electrocrystallization is a particular case of a first order phase transition” and “Electrocrystallization is a particular case of electrochemical kinetics” are two statements that I have heard and read many times. I do not like them for a simple reason: it is annoying to see that the subject to which you have devoted more than 30 years of your life may be considered as a “particular case”. Therefore, I decided to write this book in which Electrocrystallization is the main subject. To become competent in the field of Electrocrystallization one should possess knowledge of Electrochemistry, Nucleation and Crystal Growth, which means knowledge of Physical Chemistry, Physics and Mathematics. That is certainly difficult and in most cases those who study Electrocrystallization are either more electrochemists, or more physical chemists, or more physicists, very often depending on whom has been their teacher. Of course, there are scientists who consider themselves equally good in all those fields. Very frequently they are, unfortunately, equally bad. The difference is essential but strange enough, it is sometimes not easy to realize the truth immediately.
Handbook of Electrochemistry
Author: Cynthia G. Zoski
Publisher: Elsevier
ISBN: 0444519580
Category : Science
Languages : en
Pages : 935
Book Description
Electrochemistry plays a key role in a broad range of research and applied areas including the exploration of new inorganic and organic compounds, biochemical and biological systems, corrosion, energy applications involving fuel cells and solar cells, and nanoscale investigations. The Handbook of Electrochemistry serves as a source of electrochemical information, providing details of experimental considerations, representative calculations, and illustrations of the possibilities available in electrochemical experimentation. The book is divided into five parts: Fundamentals, Laboratory Practical, Techniques, Applications, and Data. The first section covers the fundamentals of electrochemistry which are essential for everyone working in the field, presenting an overview of electrochemical conventions, terminology, fundamental equations, and electrochemical cells, experiments, literature, textbooks, and specialized books. Part 2 focuses on the different laboratory aspects of electrochemistry which is followed by a review of the various electrochemical techniques ranging from classical experiments to scanning electrochemical microscopy, electrogenerated chemiluminesence and spectroelectrochemistry. Applications of electrochemistry include electrode kinetic determinations, unique aspects of metal deposition, and electrochemistry in small places and at novel interfaces and these are detailed in Part 4. The remaining three chapters provide useful electrochemical data and information involving electrode potentials, diffusion coefficients, and methods used in measuring liquid junction potentials. * serves as a source of electrochemical information * includes useful electrochemical data and information involving electrode potentials, diffusion coefficients, and methods used in measuring liquid junction potentials * reviews electrochemical techniques (incl. scanning electrochemical microscopy, electrogenerated chemiluminesence and spectroelectrochemistry)
Publisher: Elsevier
ISBN: 0444519580
Category : Science
Languages : en
Pages : 935
Book Description
Electrochemistry plays a key role in a broad range of research and applied areas including the exploration of new inorganic and organic compounds, biochemical and biological systems, corrosion, energy applications involving fuel cells and solar cells, and nanoscale investigations. The Handbook of Electrochemistry serves as a source of electrochemical information, providing details of experimental considerations, representative calculations, and illustrations of the possibilities available in electrochemical experimentation. The book is divided into five parts: Fundamentals, Laboratory Practical, Techniques, Applications, and Data. The first section covers the fundamentals of electrochemistry which are essential for everyone working in the field, presenting an overview of electrochemical conventions, terminology, fundamental equations, and electrochemical cells, experiments, literature, textbooks, and specialized books. Part 2 focuses on the different laboratory aspects of electrochemistry which is followed by a review of the various electrochemical techniques ranging from classical experiments to scanning electrochemical microscopy, electrogenerated chemiluminesence and spectroelectrochemistry. Applications of electrochemistry include electrode kinetic determinations, unique aspects of metal deposition, and electrochemistry in small places and at novel interfaces and these are detailed in Part 4. The remaining three chapters provide useful electrochemical data and information involving electrode potentials, diffusion coefficients, and methods used in measuring liquid junction potentials. * serves as a source of electrochemical information * includes useful electrochemical data and information involving electrode potentials, diffusion coefficients, and methods used in measuring liquid junction potentials * reviews electrochemical techniques (incl. scanning electrochemical microscopy, electrogenerated chemiluminesence and spectroelectrochemistry)
Electrochemical Science and Technology
Author: Keith Oldham
Publisher: John Wiley & Sons
ISBN: 0470710853
Category : Science
Languages : en
Pages : 420
Book Description
Electrochemistry is a discipline of wide scientific and technological interest. Scientifically, it explores the electrical properties of materials and especially the interfaces between different kinds of matter. Technologically, electrochemistry touches our lives in many ways that few fully appreciate; for example, materials as diverse as aluminum, nylon, and bleach are manufactured electrochemically, while the batteries that power all manner of appliances, vehicles, and devices are the products of electrochemical research. Other realms in which electrochemical science plays a crucial role include corrosion, the disinfection of water, neurophysiology, sensors, energy storage, semiconductors, the physics of thunderstorms, biomedical analysis, and so on. This book treats electrochemistry as a science in its own right, albeit resting firmly on foundations provided by chemistry, physics, and mathematics. Early chapters discuss the electrical and chemical properties of materials from which electrochemical cells are constructed. The behavior of such cells is addressed in later chapters, with emphasis on the electrodes and the reactions that occur on their surfaces. The role of transport to and from electrodes is a topic that commands attention, because it crucially determines cell efficiency. Final chapters deal with voltammetry, the methodology used to investigate electrode behavior. Interspersed among the more fundamental chapters are chapters devoted to applications of electrochemistry: electrosynthesis, power sources, “green electrochemistry”, and corrosion. Electrochemical Science and Technology is addressed to all who have a need to come to grips with the fundamentals of electrochemistry and to learn about some of its applications. It will constitute a text for a senior undergraduate or graduate course in electrochemistry. It also serves as a source of material of interest to scientists and technologists in various fields throughout academia, industry, and government – chemists, physicists, engineers, environmentalists, materials scientists, biologists, and those in related endeavors. This book: Provides a background to electrochemistry, as well as treating the topic itself. Is accessible to all with a foundation in physical science, not solely to chemists. Is addressed both to students and those later in their careers. Features web links (through www.wiley.com/go/EST) to extensive material that is of a more tangential, specialized, or mathematical nature. Includes questions as footnotes to support the reader’s evolving comprehension of the material, with fully worked answers provided on the web. Provides web access to Excel® spreadsheets which allow the reader to model electrochemical events. Has a copious Appendix of relevant data.
Publisher: John Wiley & Sons
ISBN: 0470710853
Category : Science
Languages : en
Pages : 420
Book Description
Electrochemistry is a discipline of wide scientific and technological interest. Scientifically, it explores the electrical properties of materials and especially the interfaces between different kinds of matter. Technologically, electrochemistry touches our lives in many ways that few fully appreciate; for example, materials as diverse as aluminum, nylon, and bleach are manufactured electrochemically, while the batteries that power all manner of appliances, vehicles, and devices are the products of electrochemical research. Other realms in which electrochemical science plays a crucial role include corrosion, the disinfection of water, neurophysiology, sensors, energy storage, semiconductors, the physics of thunderstorms, biomedical analysis, and so on. This book treats electrochemistry as a science in its own right, albeit resting firmly on foundations provided by chemistry, physics, and mathematics. Early chapters discuss the electrical and chemical properties of materials from which electrochemical cells are constructed. The behavior of such cells is addressed in later chapters, with emphasis on the electrodes and the reactions that occur on their surfaces. The role of transport to and from electrodes is a topic that commands attention, because it crucially determines cell efficiency. Final chapters deal with voltammetry, the methodology used to investigate electrode behavior. Interspersed among the more fundamental chapters are chapters devoted to applications of electrochemistry: electrosynthesis, power sources, “green electrochemistry”, and corrosion. Electrochemical Science and Technology is addressed to all who have a need to come to grips with the fundamentals of electrochemistry and to learn about some of its applications. It will constitute a text for a senior undergraduate or graduate course in electrochemistry. It also serves as a source of material of interest to scientists and technologists in various fields throughout academia, industry, and government – chemists, physicists, engineers, environmentalists, materials scientists, biologists, and those in related endeavors. This book: Provides a background to electrochemistry, as well as treating the topic itself. Is accessible to all with a foundation in physical science, not solely to chemists. Is addressed both to students and those later in their careers. Features web links (through www.wiley.com/go/EST) to extensive material that is of a more tangential, specialized, or mathematical nature. Includes questions as footnotes to support the reader’s evolving comprehension of the material, with fully worked answers provided on the web. Provides web access to Excel® spreadsheets which allow the reader to model electrochemical events. Has a copious Appendix of relevant data.
Fundamentals of Electrochemical Corrosion
Author: Ele Eugene Stansbury
Publisher: ASM International
ISBN: 1615030670
Category : Technology & Engineering
Languages : en
Pages : 487
Book Description
Covering the essential aspects of the corrosion behavior of metals in aqueous environments, this book is designed with the flexibility needed for use in courses for upper-level undergraduate and graduate students, for concentrated courses in industry, for individual study, and as a reference book.
Publisher: ASM International
ISBN: 1615030670
Category : Technology & Engineering
Languages : en
Pages : 487
Book Description
Covering the essential aspects of the corrosion behavior of metals in aqueous environments, this book is designed with the flexibility needed for use in courses for upper-level undergraduate and graduate students, for concentrated courses in industry, for individual study, and as a reference book.
Analytical Electrochemistry
Author: Joseph Wang
Publisher: John Wiley & Sons
ISBN: 0471460796
Category : Science
Languages : en
Pages : 228
Book Description
The critically acclaimed guide to the principles, techniques, and instruments of electroanalytical chemistry-now expanded and revised Joseph Wang, internationally renowned authority on electroanalytical techniques, thoroughly revises his acclaimed book to reflect the rapid growth the field has experienced in recent years. He substantially expands the theoretical discussion while providing comprehensive coverage of the latest advances through late 1999, introducing such exciting new topics as self-assembled monolayers, DNA biosensors, lab-on-a-chip, detection for capillary electrophoresis, single molecule detection, and sol-gel surface modification. Along with numerous references from the current literature and new worked-out examples, Analytical Electrochemistry, Second Edition offers clear, reader-friendly explanations of the fundamental principles of electrochemical processes as well as important insight into the potential of electroanalysis for problem solving in a wide range of fields, from clinical diagnostics to environmental science. Key topics include: The basics of electrode reactions and the structure of the interfacial region Tools for elucidating electrode reactions and high-resolution surface characterization An overview of finite-current controlled potential techniques Electrochemical instrumentation and electrode materials Principles of potentiometric measurements and ion-selective electrodes Chemical sensors, including biosensors, gas sensors, solid-state devices, and sensor arrays
Publisher: John Wiley & Sons
ISBN: 0471460796
Category : Science
Languages : en
Pages : 228
Book Description
The critically acclaimed guide to the principles, techniques, and instruments of electroanalytical chemistry-now expanded and revised Joseph Wang, internationally renowned authority on electroanalytical techniques, thoroughly revises his acclaimed book to reflect the rapid growth the field has experienced in recent years. He substantially expands the theoretical discussion while providing comprehensive coverage of the latest advances through late 1999, introducing such exciting new topics as self-assembled monolayers, DNA biosensors, lab-on-a-chip, detection for capillary electrophoresis, single molecule detection, and sol-gel surface modification. Along with numerous references from the current literature and new worked-out examples, Analytical Electrochemistry, Second Edition offers clear, reader-friendly explanations of the fundamental principles of electrochemical processes as well as important insight into the potential of electroanalysis for problem solving in a wide range of fields, from clinical diagnostics to environmental science. Key topics include: The basics of electrode reactions and the structure of the interfacial region Tools for elucidating electrode reactions and high-resolution surface characterization An overview of finite-current controlled potential techniques Electrochemical instrumentation and electrode materials Principles of potentiometric measurements and ion-selective electrodes Chemical sensors, including biosensors, gas sensors, solid-state devices, and sensor arrays
Crystal Growth for Beginners
Author: Ivan V. Markov
Publisher: World Scientific
ISBN: 9812382453
Category : Science
Languages : en
Pages : 566
Book Description
This is the first-ever textbook on the fundamentals of nucleation, crystal growth and epitaxy. It has been written from a unified point of view and is thus a non-eclectic presentation of this interdisciplinary topic in materials science. The reader is required to possess some basic knowledge of mathematics and physics. All formulae and equations are accompanied by examples that are of technological importance. The book presents not only the fundamentals but also the state of the art in the subject. The second revised edition includes two separate chapters dealing with the effect of the Enrich-Schwoebel barrier for down-step diffusion, as well as the effect of surface active species, on the morphology of the growing surfaces. In addition, many other chapters are updated accordingly. Thus, it serves as a valuable reference book for both graduate students and researchers in materials science.
Publisher: World Scientific
ISBN: 9812382453
Category : Science
Languages : en
Pages : 566
Book Description
This is the first-ever textbook on the fundamentals of nucleation, crystal growth and epitaxy. It has been written from a unified point of view and is thus a non-eclectic presentation of this interdisciplinary topic in materials science. The reader is required to possess some basic knowledge of mathematics and physics. All formulae and equations are accompanied by examples that are of technological importance. The book presents not only the fundamentals but also the state of the art in the subject. The second revised edition includes two separate chapters dealing with the effect of the Enrich-Schwoebel barrier for down-step diffusion, as well as the effect of surface active species, on the morphology of the growing surfaces. In addition, many other chapters are updated accordingly. Thus, it serves as a valuable reference book for both graduate students and researchers in materials science.
Electrochemical Engineering
Author: Thomas F. Fuller
Publisher: John Wiley & Sons
ISBN: 111900425X
Category : Science
Languages : en
Pages : 450
Book Description
A Comprehensive Reference for Electrochemical Engineering Theory and Application From chemical and electronics manufacturing, to hybrid vehicles, energy storage, and beyond, electrochemical engineering touches many industries—any many lives—every day. As energy conservation becomes of central importance, so too does the science that helps us reduce consumption, reduce waste, and lessen our impact on the planet. Electrochemical Engineering provides a reference for scientists and engineers working with electrochemical processes, and a rigorous, thorough text for graduate students and upper-division undergraduates. Merging theoretical concepts with widespread application, this book is designed to provide critical knowledge in a real-world context. Beginning with the fundamental principles underpinning the field, the discussion moves into industrial and manufacturing processes that blend central ideas to provide an advanced understanding while explaining observable results. Fully-worked illustrations simplify complex processes, and end-of chapter questions help reinforce essential knowledge. With in-depth coverage of both the practical and theoretical, this book is both a thorough introduction to and a useful reference for the field. Rigorous in depth, yet grounded in relevance, Electrochemical Engineering: Introduces basic principles from the standpoint of practical application Explores the kinetics of electrochemical reactions with discussion on thermodynamics, reaction fundamentals, and transport Covers battery and fuel cell characteristics, mechanisms, and system design Delves into the design and mechanics of hybrid and electric vehicles, including regenerative braking, start-stop hybrids, and fuel cell systems Examines electrodeposition, redox-flow batteries, electrolysis, regenerative fuel cells, semiconductors, and other applications of electrochemical engineering principles Overlapping chemical engineering, chemistry, material science, mechanical engineering, and electrical engineering, electrochemical engineering covers a diverse array of phenomena explained by some of the important scientific discoveries of our time. Electrochemical Engineering provides the critical understanding required to work effectively with these processes as they become increasingly central to global sustainability.
Publisher: John Wiley & Sons
ISBN: 111900425X
Category : Science
Languages : en
Pages : 450
Book Description
A Comprehensive Reference for Electrochemical Engineering Theory and Application From chemical and electronics manufacturing, to hybrid vehicles, energy storage, and beyond, electrochemical engineering touches many industries—any many lives—every day. As energy conservation becomes of central importance, so too does the science that helps us reduce consumption, reduce waste, and lessen our impact on the planet. Electrochemical Engineering provides a reference for scientists and engineers working with electrochemical processes, and a rigorous, thorough text for graduate students and upper-division undergraduates. Merging theoretical concepts with widespread application, this book is designed to provide critical knowledge in a real-world context. Beginning with the fundamental principles underpinning the field, the discussion moves into industrial and manufacturing processes that blend central ideas to provide an advanced understanding while explaining observable results. Fully-worked illustrations simplify complex processes, and end-of chapter questions help reinforce essential knowledge. With in-depth coverage of both the practical and theoretical, this book is both a thorough introduction to and a useful reference for the field. Rigorous in depth, yet grounded in relevance, Electrochemical Engineering: Introduces basic principles from the standpoint of practical application Explores the kinetics of electrochemical reactions with discussion on thermodynamics, reaction fundamentals, and transport Covers battery and fuel cell characteristics, mechanisms, and system design Delves into the design and mechanics of hybrid and electric vehicles, including regenerative braking, start-stop hybrids, and fuel cell systems Examines electrodeposition, redox-flow batteries, electrolysis, regenerative fuel cells, semiconductors, and other applications of electrochemical engineering principles Overlapping chemical engineering, chemistry, material science, mechanical engineering, and electrical engineering, electrochemical engineering covers a diverse array of phenomena explained by some of the important scientific discoveries of our time. Electrochemical Engineering provides the critical understanding required to work effectively with these processes as they become increasingly central to global sustainability.