Definition
CALPHAD stands for Calculation of PHAse Diagrams. An equilibrium phase diagram is usually a diagram with axes for temperature and composition of a chemical system. It shows the regions where substances or solutions (i.e. phases) are stable and regions where two or more of them coexist. Phase diagrams are a very powerful tool for predicting the state of a system under different conditions and were initially a graphical method to rationalize experimental information on states of equilibrium. The CALPHAD approach is based on the fact that a phase diagram is a manifestation of the equilibrium thermodynamic properties of the system, which are the sum of the properties of the individual phases. It is thus possible to calculate a phase diagram by first assessing the thermodynamic properties of all the phases in a system.
Methodology
With the CALPHAD method one collects all experimental information on phase equilibria in a system and all thermodynamic information obtained from thermochemical and thermophysical studies. The thermodynamic properties of each phase are then described with a mathematical model containing adjustable parameters. The parameters are evaluated by optimizing the fit of the model to all the information, also involving coexisting phases. It is then possible to recalculate the phase diagram as well as the thermodynamic properties of all the phases. The philosophy of the CALPHAD method is to obtain a consistent description of the phase diagram and the thermodynamic properties so to reliably predict the set of stable phases and their thermodynamic properties in regions without experimental information and for metastable states during simulations of phase transformations.
There are two crucial factors for the success of the CALPHAD method. The first factor is to find realistic as well as convenient mathematical models for the Gibbs energy for each phase. The Gibbs energy is used because most experimental data have been determined at known temperature and pressure and any other thermodynamic quantities can be calculated from it. It is not possible to obtain an exact description of the behavior of the Gibbs energy of a multi-component system with analytical expressions. It is thus necessary to identify the main features and base the mathematical models on them. The discrepancy between model and reality is finally represented by a power series expansion in temperature, pressure and constitution of the phase. The adjustable parameters of these model descriptions are refined to reproduce the experimental data. The strength of the CALPHAD method is that the descriptions of the constituent sub-systems can be combined to describe a multi-component system.
The second crucial factor is the availability of computer software for calculating equilibria and various kinds of diagrams and databases with the stored assessed information. As there are at present many different kinds of models used for different kinds of phases there are several thermodynamic databases available, either free or commercially, for different materials like steels, super-alloys, semiconductor materials, aqueous solutions, slags, etc. There are also several different kinds of software available using different kinds of algorithms for computing the equilibrium. It is an advantage if the software allows the equilibrium to be calculated using many different types of conditions for the system, not only the temperature, pressure and overall composition because in many cases the equilibrium may be determined at constant volume or at a given chemical potential of an element or a given composition of a particular phase.
Applications
CALPHAD had a slow start in the 60’s but sophisticated thermodynamic data bank systems started to appear in the 80’s and today there are several commercial products on the market, e.g. , , and . They are used in research and industrial development, where they save large amounts of time and resources by reducing the experimental work and by making thermodynamic predictions available for multi-component systems that would be practically non-attainable without this approach. There is a journal with this name where recent scientific achievements are published but scientific papers describing the use of the CALPHAD methods are published also in many other journals.
CALPHAD stands for Calculation of PHAse Diagrams. An equilibrium phase diagram is usually a diagram with axes for temperature and composition of a chemical system. It shows the regions where substances or solutions (i.e. phases) are stable and regions where two or more of them coexist. Phase diagrams are a very powerful tool for predicting the state of a system under different conditions and were initially a graphical method to rationalize experimental information on states of equilibrium. The CALPHAD approach is based on the fact that a phase diagram is a manifestation of the equilibrium thermodynamic properties of the system, which are the sum of the properties of the individual phases. It is thus possible to calculate a phase diagram by first assessing the thermodynamic properties of all the phases in a system.
Methodology
With the CALPHAD method one collects all experimental information on phase equilibria in a system and all thermodynamic information obtained from thermochemical and thermophysical studies. The thermodynamic properties of each phase are then described with a mathematical model containing adjustable parameters. The parameters are evaluated by optimizing the fit of the model to all the information, also involving coexisting phases. It is then possible to recalculate the phase diagram as well as the thermodynamic properties of all the phases. The philosophy of the CALPHAD method is to obtain a consistent description of the phase diagram and the thermodynamic properties so to reliably predict the set of stable phases and their thermodynamic properties in regions without experimental information and for metastable states during simulations of phase transformations.
There are two crucial factors for the success of the CALPHAD method. The first factor is to find realistic as well as convenient mathematical models for the Gibbs energy for each phase. The Gibbs energy is used because most experimental data have been determined at known temperature and pressure and any other thermodynamic quantities can be calculated from it. It is not possible to obtain an exact description of the behavior of the Gibbs energy of a multi-component system with analytical expressions. It is thus necessary to identify the main features and base the mathematical models on them. The discrepancy between model and reality is finally represented by a power series expansion in temperature, pressure and constitution of the phase. The adjustable parameters of these model descriptions are refined to reproduce the experimental data. The strength of the CALPHAD method is that the descriptions of the constituent sub-systems can be combined to describe a multi-component system.
The second crucial factor is the availability of computer software for calculating equilibria and various kinds of diagrams and databases with the stored assessed information. As there are at present many different kinds of models used for different kinds of phases there are several thermodynamic databases available, either free or commercially, for different materials like steels, super-alloys, semiconductor materials, aqueous solutions, slags, etc. There are also several different kinds of software available using different kinds of algorithms for computing the equilibrium. It is an advantage if the software allows the equilibrium to be calculated using many different types of conditions for the system, not only the temperature, pressure and overall composition because in many cases the equilibrium may be determined at constant volume or at a given chemical potential of an element or a given composition of a particular phase.
Applications
CALPHAD had a slow start in the 60’s but sophisticated thermodynamic data bank systems started to appear in the 80’s and today there are several commercial products on the market, e.g. , , and . They are used in research and industrial development, where they save large amounts of time and resources by reducing the experimental work and by making thermodynamic predictions available for multi-component systems that would be practically non-attainable without this approach. There is a journal with this name where recent scientific achievements are published but scientific papers describing the use of the CALPHAD methods are published also in many other journals.
SingSing was a rock musical group formed in Kansas City, Missouri in 1990. The lineup included Johnny Wayne on Guitar, Bryan Portera on bass, Patrick Mullendore on keyboards and Aaron Mumma who replaced original drummer Mark Wulff. The band became one of the most popular club acts in the Midwest before touring the United States in support of their one and only release in 1994. The first single from the self-titled "SingSing" called "Wheels In Motion" gained popularity as an anthem for Harley-Davidson motorcycle riders. Despite the popularity of the song in middle America, it was unable to gain airplay in the major markets on the East and West coast and the group disbanded in 1995.
The "Sailboat 4" was the logo used by television station WTMJ in Milwaukee, Wisconsin. It was retired in 2004 after having been in use (in some form) for a total of 31 years. It was referred to as such because the inside of the 4 made the shape of a sail, which could allude to the numerous sailboats found on Milwaukee's Lakefront in the summer months. During its run, it became one of the most recognizable local television station logos in the United States.
The "Unofficial" Sailboat 4's
Although it is not recognized as an "official" Sailboat 4, this version shares some similarities with the Sailboat 4 and in many ways can be seen as the precursor to the future logo. It debuted in 1967 with the television colors of red, blue and green chosen to promote the station's conversion to full color capability. In 1976, the logo was given a makeover and skewed towards red, white and blue and a star was added to celebrate the American Bicentennial before giving way to the "Tube 4" the following year.
First Generation Sailboat 4/Peacock 4
The First Generation Sailboat 4 debuted in 1980. It would become a staple on Milwaukee television for the next 23 years, undergoing only evolutionary changes during that time. The current NBC Peacock was unvieled on May 12, 1986 and soon appeared alongside the Sailboat 4 per a mandate to all of the networks affiliates. The "Peacock 4" was shown numerous times in the 1988 movie Major League which was filmed on-location in Milwaukee. The movie even featured a scene where a player was being interviewed by a WTMJ reporter, but the station was based in Cleveland for continuity purposes.
"Today's TMJ" Version
The final version of the Sailboat 4 debuted in 1992 during the Summer Olympic Games to help launch a new campaign featuring the station's new marketing slogan "Today's TMJ." The slogan was also the first to acknowledge the colloquial term "TMJ" which had long been used by viewers to refer to the station. Minimal changes were made to the logo as it was slanted towards the right giving it the appearance of moving forward with the colors being skewed towards gold, purple and red. A second version using green and gold was used for broadcasts involving the Green Bay Packers. The reasons for this were two-fold. It not only showed the stations status as the "Official Packers Station" in Milwaukee, but it was also felt the regular colors too closely resembled the Packers' rivals, the Minnesota Vikings. The Sailboat 4 was finally retired in 2004 when it was thought to look too dated for the HDTV generation (Ironically, rival Milwaukee station WISN is still using its even older "12" logo). the current glossier 4 debuted during the 2004 Olympics, ending the Sailboat 4's run as the longest continuously used logo in the station's history.
The "Unofficial" Sailboat 4's
Although it is not recognized as an "official" Sailboat 4, this version shares some similarities with the Sailboat 4 and in many ways can be seen as the precursor to the future logo. It debuted in 1967 with the television colors of red, blue and green chosen to promote the station's conversion to full color capability. In 1976, the logo was given a makeover and skewed towards red, white and blue and a star was added to celebrate the American Bicentennial before giving way to the "Tube 4" the following year.
First Generation Sailboat 4/Peacock 4
The First Generation Sailboat 4 debuted in 1980. It would become a staple on Milwaukee television for the next 23 years, undergoing only evolutionary changes during that time. The current NBC Peacock was unvieled on May 12, 1986 and soon appeared alongside the Sailboat 4 per a mandate to all of the networks affiliates. The "Peacock 4" was shown numerous times in the 1988 movie Major League which was filmed on-location in Milwaukee. The movie even featured a scene where a player was being interviewed by a WTMJ reporter, but the station was based in Cleveland for continuity purposes.
"Today's TMJ" Version
The final version of the Sailboat 4 debuted in 1992 during the Summer Olympic Games to help launch a new campaign featuring the station's new marketing slogan "Today's TMJ." The slogan was also the first to acknowledge the colloquial term "TMJ" which had long been used by viewers to refer to the station. Minimal changes were made to the logo as it was slanted towards the right giving it the appearance of moving forward with the colors being skewed towards gold, purple and red. A second version using green and gold was used for broadcasts involving the Green Bay Packers. The reasons for this were two-fold. It not only showed the stations status as the "Official Packers Station" in Milwaukee, but it was also felt the regular colors too closely resembled the Packers' rivals, the Minnesota Vikings. The Sailboat 4 was finally retired in 2004 when it was thought to look too dated for the HDTV generation (Ironically, rival Milwaukee station WISN is still using its even older "12" logo). the current glossier 4 debuted during the 2004 Olympics, ending the Sailboat 4's run as the longest continuously used logo in the station's history.
Dr Neel L. Burton (born 3 June 1978 in Mauritius, Indian Ocean) qualified in medicine from King's College London, UK in 2002. He is currently specialising in psychiatry in Oxford, UK.
As the author of two medical textbooks, Clinical Skills for OSCEs and Psychiatry, he has made a notable contribution to medical education.
Medical textbooks
Clinical Skills for OSCEs is a preparation guide for medical students preparing to take their "OSCE" (Objective Structured Clinical Examination) or practical exam. It contains 112 clinical scenarios covering medical histories, physical examinations, investigative procedures, and communication skills. It is currently in its second edition, and has been translated into a number of foreign languages.
Psychiatry is an innovative textbook of psychiatry employing artistic and literary excerpts to stimulate the reader to think more deeply about the subject matter of psychiatry and, in so doing, challenge the stigma attached to mental illness. In his foreword, Professor John Cox, Secretary General of the World Psychiatric Association, praised the textbook for providing a fresh perspective to the field. In a review in the International Journal of Psychiatry in Clinical Practice (11(1): 79), Dr Khalil Ajel of Southampton University called the textbook "excellent, enjoyable, and enlivening". In September 2007, the textbook was short-listed for the Society of Authors and Royal Society of Medicine Richard Asher Prize.
Living with Schizophrenia
Living with Schizophrenia, Neel Burton's third book (co-authored with Dr Phil Davison), is an information and self-help guide for schizophrenia-sufferers and their friends, relatives, and carers. Living with Schizophrenia is due to be published in December 2007, and has been endorsed by Marjorie Wallace, Chief Executive of the UK mental health charity SANE.
Bibliography
- Clinical Skills for OSCEs (2003, 2006) ISBN 1859963404
- Psychiatry (2006) ISBN 1405136529
- Living with Schizophrenia (2007)
As the author of two medical textbooks, Clinical Skills for OSCEs and Psychiatry, he has made a notable contribution to medical education.
Medical textbooks
Clinical Skills for OSCEs is a preparation guide for medical students preparing to take their "OSCE" (Objective Structured Clinical Examination) or practical exam. It contains 112 clinical scenarios covering medical histories, physical examinations, investigative procedures, and communication skills. It is currently in its second edition, and has been translated into a number of foreign languages.
Psychiatry is an innovative textbook of psychiatry employing artistic and literary excerpts to stimulate the reader to think more deeply about the subject matter of psychiatry and, in so doing, challenge the stigma attached to mental illness. In his foreword, Professor John Cox, Secretary General of the World Psychiatric Association, praised the textbook for providing a fresh perspective to the field. In a review in the International Journal of Psychiatry in Clinical Practice (11(1): 79), Dr Khalil Ajel of Southampton University called the textbook "excellent, enjoyable, and enlivening". In September 2007, the textbook was short-listed for the Society of Authors and Royal Society of Medicine Richard Asher Prize.
Living with Schizophrenia
Living with Schizophrenia, Neel Burton's third book (co-authored with Dr Phil Davison), is an information and self-help guide for schizophrenia-sufferers and their friends, relatives, and carers. Living with Schizophrenia is due to be published in December 2007, and has been endorsed by Marjorie Wallace, Chief Executive of the UK mental health charity SANE.
Bibliography
- Clinical Skills for OSCEs (2003, 2006) ISBN 1859963404
- Psychiatry (2006) ISBN 1405136529
- Living with Schizophrenia (2007)