This page contains locations from the His Dark Materials trilogy by Philip Pullman.
Bolvangar
Bolvangar, meaning the Fields of Evil, is a fictional place where there is an experimental station set up by the General Oblation Board in order to conduct experiments involving intercision, the process of severing a child from his or her dæmon (an external manifestation of the soul in animal form). Large numbers of children have been taken as a result, including children of the Gyptian people and Roger, a friend of Lyra Belacqua and former kitchen-hand from Jordan College, Oxford. Lyra manages to save most of the children who have been kidnapped and return them to the Gyptians, who have come to rescue them. The station at Bolvangar is apparently destroyed in the ensuing battle.)
Bolvangar appears in Northern Lights (The Golden Compass).
Svalbard
Svalbard is the real-life name of an island in the Arctic. In His Dark Materials it is the home of the panserbjørne, large and robust bears that almost always wear their armour consisting of flawless metal. Iofur Raknison, the King of Svalbard and the panserbjørne for a brief time, built a palace of marble and gold on Svalbard that Iorek Byrnison destroyed after killing Iofur Raknison in a fight and becoming king. Svalbard appears only in Northern Lights (The Golden Compass).
Cittàgazze
Cittàgazze (sometimes abbreviated to Ci'gazze out of slang), is a fictional city within an unknown world (and parallel universe). It is occasionally and informally called the 'City of Magpies'.
Cittàgazze is a seaside town, reminiscent of those near the Mediterranean, which seems to have Italian-like roots. Its main features are quaint restaurants and cafés, parasols hung over circular tables beneath trailing plants, wide cobbled roads, and ancient architecture. However, it should not necessarily be considered "old-world". There is mention of electric devices (electric lights and refrigerators) and the world appears to be roughly as technological as our own. Furthermore, the world contains familiar brand names such as Coca Cola.
The world of Cittàgazze is plagued by deadly, ghostly beings called Spectres. They are invisible to pre-adolescents, but once individuals are old enough to see them (and are post-pubescent), the spectres take an interest in them, eating away the people's souls (or dæmon in the case those whose soul has taken an external manifestation) leaving them alive but zombie-like. Spectres cluster around children approaching adolescence and consume them the moment they come of age. However, they avoid the Torre degli Angeli because within the tower is the Æsahættr, an item which they avoid.
Spectres have been common in this world for several generations, however their number was greatly multiplied after Lord Asriel created a huge window through his world into that of Cittàgazze. This huge upsurge of the soul-devouring wraiths is why the city is entirely devoid of adults and is populated by small rag-tag gangs of children called spectre-orphans. Later in The Subtle Knife it is learned that the adults are elsewhere in order to escape the spectres. Ironically, the creation of spectres in Cittàgazze is due to the constant use of the Æsahættr in its vicinity. The knife, which can create windows to other worlds, creates a new spectre every time it is used to open such a window. The world of Cittàgazze was once prosperous, however it had come upon hard times three hundred years earlier and so the philosophers of the guild of the Torre degli Angeli would use the Æsahættr to open windows into other worlds and steal things to regain wealth. This was how the city earned the nickname of the 'City of Magpies', referring to the same thieving characteristic that is inherent in the bird.
The first reference to the city appears in the first volume of the trilogy, Northern Lights (The Golden Compass), as 'the city in the sky' (the city visible in the aurora borealis, an occurrence which, according to the novel, thins the barrier between the dimension in which the story takes place and the dimension of Cittàgazze). The most expansive description of the city is given as Lyra and Will venture into it and other surrounding universes in The Subtle Knife. It is also mentioned in the final volume, The Amber Spyglass, but is no more significant than as a point of transit between Lyra and Will's worlds.
Torre degli Angeli
Perhaps the most significant feature of Cittàgazze, the Torre degli Angeli (Tower of Angels) is a great tower of old-style architecture that stands in the middle of the spectre-haunted city. It was once the home of the philosophers that created Æsahættr, the subtle knife, where it still resides. It is in the Torre degli Angeli that Will Parry fights a young man called Tullio and obtains the blade and later where Giacomo Paradisi, the ex-bearer of the knife, teaches Will Parry how to use it. The knife first appears in The Subtle Knife.
The Clouded Mountain
The Clouded Mountain (also known as the Chariot) is a giant mountain fortress surrounded by mist and clouds. It is home to The Authority (God), Metatron (the Regent of Heaven), and a citadel to all angels apart from the rebels. It is defended with gun emplacements built into the rock and can apparently move under its own power.
It is described only once in the series, in The Amber Spyglass, when Mrs Coulter arrives there in The Intention Craft, to trick the Regent into following her to his death when she plunges him into the empty abyss created by an interdimensional bomb the Magisterium set off to kill Lyra Belacqua. The Clouded Mountain's fate is not revealed, but it can be presumed it was destroyed or captured after Metatron's death in the abyss.
Jordan College, Oxford
Jordan College is a college of the University of Oxford in Lyra's world, and is considered her home.
The Jordan College appears at the beginning of Northern Lights (The Golden Compass) and at the end of The Amber Spyglass, and is the primary setting of Lyra's Oxford.
For detailed information, see the main article.
University of Oxford Botanic Garden
The University of Oxford Botanic Garden, which exists in both Lyra and Will's world, is home to a bench with a special significance to them both. The bench, featured late in The Amber Spyglass, actually exists.
His Dark Materials
Locations
Bolvangar
Bolvangar, meaning the Fields of Evil, is a fictional place where there is an experimental station set up by the General Oblation Board in order to conduct experiments involving intercision, the process of severing a child from his or her dæmon (an external manifestation of the soul in animal form). Large numbers of children have been taken as a result, including children of the Gyptian people and Roger, a friend of Lyra Belacqua and former kitchen-hand from Jordan College, Oxford. Lyra manages to save most of the children who have been kidnapped and return them to the Gyptians, who have come to rescue them. The station at Bolvangar is apparently destroyed in the ensuing battle.)
Bolvangar appears in Northern Lights (The Golden Compass).
Svalbard
Svalbard is the real-life name of an island in the Arctic. In His Dark Materials it is the home of the panserbjørne, large and robust bears that almost always wear their armour consisting of flawless metal. Iofur Raknison, the King of Svalbard and the panserbjørne for a brief time, built a palace of marble and gold on Svalbard that Iorek Byrnison destroyed after killing Iofur Raknison in a fight and becoming king. Svalbard appears only in Northern Lights (The Golden Compass).
Cittàgazze
Cittàgazze (sometimes abbreviated to Ci'gazze out of slang), is a fictional city within an unknown world (and parallel universe). It is occasionally and informally called the 'City of Magpies'.
Cittàgazze is a seaside town, reminiscent of those near the Mediterranean, which seems to have Italian-like roots. Its main features are quaint restaurants and cafés, parasols hung over circular tables beneath trailing plants, wide cobbled roads, and ancient architecture. However, it should not necessarily be considered "old-world". There is mention of electric devices (electric lights and refrigerators) and the world appears to be roughly as technological as our own. Furthermore, the world contains familiar brand names such as Coca Cola.
The world of Cittàgazze is plagued by deadly, ghostly beings called Spectres. They are invisible to pre-adolescents, but once individuals are old enough to see them (and are post-pubescent), the spectres take an interest in them, eating away the people's souls (or dæmon in the case those whose soul has taken an external manifestation) leaving them alive but zombie-like. Spectres cluster around children approaching adolescence and consume them the moment they come of age. However, they avoid the Torre degli Angeli because within the tower is the Æsahættr, an item which they avoid.
Spectres have been common in this world for several generations, however their number was greatly multiplied after Lord Asriel created a huge window through his world into that of Cittàgazze. This huge upsurge of the soul-devouring wraiths is why the city is entirely devoid of adults and is populated by small rag-tag gangs of children called spectre-orphans. Later in The Subtle Knife it is learned that the adults are elsewhere in order to escape the spectres. Ironically, the creation of spectres in Cittàgazze is due to the constant use of the Æsahættr in its vicinity. The knife, which can create windows to other worlds, creates a new spectre every time it is used to open such a window. The world of Cittàgazze was once prosperous, however it had come upon hard times three hundred years earlier and so the philosophers of the guild of the Torre degli Angeli would use the Æsahættr to open windows into other worlds and steal things to regain wealth. This was how the city earned the nickname of the 'City of Magpies', referring to the same thieving characteristic that is inherent in the bird.
The first reference to the city appears in the first volume of the trilogy, Northern Lights (The Golden Compass), as 'the city in the sky' (the city visible in the aurora borealis, an occurrence which, according to the novel, thins the barrier between the dimension in which the story takes place and the dimension of Cittàgazze). The most expansive description of the city is given as Lyra and Will venture into it and other surrounding universes in The Subtle Knife. It is also mentioned in the final volume, The Amber Spyglass, but is no more significant than as a point of transit between Lyra and Will's worlds.
Torre degli Angeli
Perhaps the most significant feature of Cittàgazze, the Torre degli Angeli (Tower of Angels) is a great tower of old-style architecture that stands in the middle of the spectre-haunted city. It was once the home of the philosophers that created Æsahættr, the subtle knife, where it still resides. It is in the Torre degli Angeli that Will Parry fights a young man called Tullio and obtains the blade and later where Giacomo Paradisi, the ex-bearer of the knife, teaches Will Parry how to use it. The knife first appears in The Subtle Knife.
The Clouded Mountain
The Clouded Mountain (also known as the Chariot) is a giant mountain fortress surrounded by mist and clouds. It is home to The Authority (God), Metatron (the Regent of Heaven), and a citadel to all angels apart from the rebels. It is defended with gun emplacements built into the rock and can apparently move under its own power.
It is described only once in the series, in The Amber Spyglass, when Mrs Coulter arrives there in The Intention Craft, to trick the Regent into following her to his death when she plunges him into the empty abyss created by an interdimensional bomb the Magisterium set off to kill Lyra Belacqua. The Clouded Mountain's fate is not revealed, but it can be presumed it was destroyed or captured after Metatron's death in the abyss.
Jordan College, Oxford
Jordan College is a college of the University of Oxford in Lyra's world, and is considered her home.
The Jordan College appears at the beginning of Northern Lights (The Golden Compass) and at the end of The Amber Spyglass, and is the primary setting of Lyra's Oxford.
For detailed information, see the main article.
University of Oxford Botanic Garden
The University of Oxford Botanic Garden, which exists in both Lyra and Will's world, is home to a bench with a special significance to them both. The bench, featured late in The Amber Spyglass, actually exists.
His Dark Materials
Locations
Matilda Harriet Jane Hunter (often referred to as "Mattie") is a fictional character in the Australian soap opera Home and Away. She has been portrayed by actress Indiana Evans since January 2004.
Character
When Matilda’s father, Jack Hunter, decided there was no future on the farm, he sent his youngest daughter and her twin brother, Henry (Tobi Atkins), to boarding school. Matilda and Henry would visit their family during school holidays in Summer Bay.
This became more of a permanent arrangement when their father died and Matilda soon settled into Summer Bay. While at first Matilda was a selfish, snobby "drama queen", she mellowed.
She is passionate about music, movies and horse riding and is kind and caring toward animals. When Matilda met Lucas Holden (Rhys Wakefield), her new neighbour, they soon fell in love. When Matilda's mother Beth (Clarissa House) and Lucas' father Tony (Jon Sivewright) fell in love, they decided to share the same house.
When Matilda and Lucas broke up, Matilda was devastated. As a result of this stress, issues with self-esteem plus having family members Kit (Amy Mizzi) and Robbie (Jason Smith) lost in the bush, Matilda developed bulimia. Having overcome that, she is currently trying to focus on friends, school and a new relationship with Ric Dalby (Mark Furze), whom she lost her virginity to.
She had developed a rivalry with Belle Taylor due to Belle breaking up Cassie Turner, Matilda's best friend, and Ric. Ironically, Matilda, now dating Cassie's and Belle's ex-boyfriend Ric, and Belle, now dating Matilda's ex-boyfriend Lucas, were forced to meet together due to Ric and Lucas' close friendship. Although Belle and Matilda are not the closest of friends, they are no longer arch-rivals.
Then, Beth, her mother died in a car crash. This sent her into absolute shock and devastation which made her run away from home. Along the way she fell into the sea. Lily jumps in after her but a sudden ocean rip knocks her unconscious placing both their lives in danger. However Ric then rescues the both of them from further danger.
After finding out that Ric knew that Tony had slept with her English teacher, Naomi Preston, she began to shut him out and she and Lucas got drunk in the beach party when at Drew's 18th birthday. When Matilda sees Ric with another woman she thinks he is cheating on her. She soon finds out that this is untrue. In an attempt to make her see that he loves her, he gets the engagement ring that her mother left her in her will and gets it shaped and resized.
Then, a new teen named Reuben arrived. She took an instant liking to him and in the process got Ric concerned that she was cheating on him. His suspicions were confirmed when he caught the pair kissing at a party. Despite Ric's attempts to reassure her that they will always be together, Matilda didn't think so. Feeling alone she left Summer Bay with Reuben, determined never to return.
Reuben has tried to kiss her more than once but she resists saying she does not feel that way about him and also they always get interuppted by Ric, who had a punch up with Reuben as he thought they were having sex in his van. It was then confirmed that it wasn't Mattie and it was another girl. Although Ric wanted to try to reason with her, Matilda told him she never wanted to speak to or see him again.
After her best friend Cassie persuaded her to come home, Matilda tried to show Ric they still have a future together, by asking to live with him. Unfortunately, Sally decided it was too early in their relationship for this to happen. Matilda decided to move into the Diner Flat, sharing it with Martha. After sharing the flat with Martha for a bit, Matilda decided it was too much for her so she decided to move back in with Tony and Lucas.
More recently Ric found a pregnancy test in the bin which was Emma's but he thought it was Mattie's. When he said, "We can work this out, I promise," she told him it was none of his business, thinking it was about her cheating on a test. Then he said, "It's my baby," and she told him that she wasn't pregnant. Donald Fisher, the deputy principal, eventually found out that Matilda and her friend, Emma, had cheated on their first HSC exam. After talking to Sally Fletcher about her punishment, Sally and Don decided to take marks off her exam. However, Matilda had already scored below the pass mark, leading her to fail her best subject, Maths.
Lately Matilda and her boyfriend Ric have been going through tough times after Ric's attraction to a married woman called Viv Anderson. There were many problems but they managed to get over it. Recently, Noel Anderson, Viv's husband, suspects Viv of cheating with Ric. However, he was cheating himself with a blonde woman. At the year 12 formal, Ric and Matilda break up after Noel came and accused Ric in front of Matilda. Matilda said that she could not trust him anymore and breaks up. Ric then kisses Viv passionately. The next day Matilda and Ric talk things through and are back together. Or were they? Just a few days later, Viv revealed to Matilda about her and Ric sleeping together. Ric denied this instanly but when Matilda overheard Ric telling his best mate, Lucas, about Viv being pregnant, she knew that enough was enough! She had announced that their relationship was over; this time, it was for ever.
In the upcoming 2008 season, she is set to strike up a long-term relationship with new character, Roman. Although Ric desperately continues to try to win her back, she then says to him "go find some other woman to spend the rest of your life with". So are they really over? Only time will tell.
Family Tree
*Graham Walters (grandfather, deceased) married to Amanda Walters (step-grandmother)
**Elizabeth Walters (mother, deceased), married to Jack Hunter (father, deceased) and Rhys Sutherland (divorced)
***Scott Hunter (brother), engaged to Hayley Lawson
****Noah Lawson II (nephew)
***Kit Hunter (sister), in a relationship with Kim Hyde
****Archie Hunter (nephew)
***Robert Hunter (brother), married to Natasha Andrews
****Ella Hunter (niece)
***Henry Hunter (brother)
Character
When Matilda’s father, Jack Hunter, decided there was no future on the farm, he sent his youngest daughter and her twin brother, Henry (Tobi Atkins), to boarding school. Matilda and Henry would visit their family during school holidays in Summer Bay.
This became more of a permanent arrangement when their father died and Matilda soon settled into Summer Bay. While at first Matilda was a selfish, snobby "drama queen", she mellowed.
She is passionate about music, movies and horse riding and is kind and caring toward animals. When Matilda met Lucas Holden (Rhys Wakefield), her new neighbour, they soon fell in love. When Matilda's mother Beth (Clarissa House) and Lucas' father Tony (Jon Sivewright) fell in love, they decided to share the same house.
When Matilda and Lucas broke up, Matilda was devastated. As a result of this stress, issues with self-esteem plus having family members Kit (Amy Mizzi) and Robbie (Jason Smith) lost in the bush, Matilda developed bulimia. Having overcome that, she is currently trying to focus on friends, school and a new relationship with Ric Dalby (Mark Furze), whom she lost her virginity to.
She had developed a rivalry with Belle Taylor due to Belle breaking up Cassie Turner, Matilda's best friend, and Ric. Ironically, Matilda, now dating Cassie's and Belle's ex-boyfriend Ric, and Belle, now dating Matilda's ex-boyfriend Lucas, were forced to meet together due to Ric and Lucas' close friendship. Although Belle and Matilda are not the closest of friends, they are no longer arch-rivals.
Then, Beth, her mother died in a car crash. This sent her into absolute shock and devastation which made her run away from home. Along the way she fell into the sea. Lily jumps in after her but a sudden ocean rip knocks her unconscious placing both their lives in danger. However Ric then rescues the both of them from further danger.
After finding out that Ric knew that Tony had slept with her English teacher, Naomi Preston, she began to shut him out and she and Lucas got drunk in the beach party when at Drew's 18th birthday. When Matilda sees Ric with another woman she thinks he is cheating on her. She soon finds out that this is untrue. In an attempt to make her see that he loves her, he gets the engagement ring that her mother left her in her will and gets it shaped and resized.
Then, a new teen named Reuben arrived. She took an instant liking to him and in the process got Ric concerned that she was cheating on him. His suspicions were confirmed when he caught the pair kissing at a party. Despite Ric's attempts to reassure her that they will always be together, Matilda didn't think so. Feeling alone she left Summer Bay with Reuben, determined never to return.
Reuben has tried to kiss her more than once but she resists saying she does not feel that way about him and also they always get interuppted by Ric, who had a punch up with Reuben as he thought they were having sex in his van. It was then confirmed that it wasn't Mattie and it was another girl. Although Ric wanted to try to reason with her, Matilda told him she never wanted to speak to or see him again.
After her best friend Cassie persuaded her to come home, Matilda tried to show Ric they still have a future together, by asking to live with him. Unfortunately, Sally decided it was too early in their relationship for this to happen. Matilda decided to move into the Diner Flat, sharing it with Martha. After sharing the flat with Martha for a bit, Matilda decided it was too much for her so she decided to move back in with Tony and Lucas.
More recently Ric found a pregnancy test in the bin which was Emma's but he thought it was Mattie's. When he said, "We can work this out, I promise," she told him it was none of his business, thinking it was about her cheating on a test. Then he said, "It's my baby," and she told him that she wasn't pregnant. Donald Fisher, the deputy principal, eventually found out that Matilda and her friend, Emma, had cheated on their first HSC exam. After talking to Sally Fletcher about her punishment, Sally and Don decided to take marks off her exam. However, Matilda had already scored below the pass mark, leading her to fail her best subject, Maths.
Lately Matilda and her boyfriend Ric have been going through tough times after Ric's attraction to a married woman called Viv Anderson. There were many problems but they managed to get over it. Recently, Noel Anderson, Viv's husband, suspects Viv of cheating with Ric. However, he was cheating himself with a blonde woman. At the year 12 formal, Ric and Matilda break up after Noel came and accused Ric in front of Matilda. Matilda said that she could not trust him anymore and breaks up. Ric then kisses Viv passionately. The next day Matilda and Ric talk things through and are back together. Or were they? Just a few days later, Viv revealed to Matilda about her and Ric sleeping together. Ric denied this instanly but when Matilda overheard Ric telling his best mate, Lucas, about Viv being pregnant, she knew that enough was enough! She had announced that their relationship was over; this time, it was for ever.
In the upcoming 2008 season, she is set to strike up a long-term relationship with new character, Roman. Although Ric desperately continues to try to win her back, she then says to him "go find some other woman to spend the rest of your life with". So are they really over? Only time will tell.
Family Tree
*Graham Walters (grandfather, deceased) married to Amanda Walters (step-grandmother)
**Elizabeth Walters (mother, deceased), married to Jack Hunter (father, deceased) and Rhys Sutherland (divorced)
***Scott Hunter (brother), engaged to Hayley Lawson
****Noah Lawson II (nephew)
***Kit Hunter (sister), in a relationship with Kim Hyde
****Archie Hunter (nephew)
***Robert Hunter (brother), married to Natasha Andrews
****Ella Hunter (niece)
***Henry Hunter (brother)
eccount is a financial term describing a safe way to store, manage, spend, share, receive and withdraw funds that are held in the form of electronic money.
An eccount can be topped-up with cash at retail outlets, Post Offices®, some bank branches, online by debit or credit card, or by bank transfer and standing order. Wages or salaries can also be paid directly into an eccount.
An eccount offers users a range of features to help them manage their money such as a 24 hour interface from mobile phones, the internet or telephone to access their eccount balance and exchange rates; the ability to move funds to an authorised user’s card; flexibility to set up text alerts; locking and unlocking cards for extra security.
Using a prepaid card (not a debit or credit card) that is issued together with an eccount, funds held can be used to make payments, purchase goods in stores, shop online, buy over the phone or order goods by mail. Cash can also be withdrawn at ATMs throughout the world. Prepaid cards are issued in conjunction with leading international payment networks such as MasterCard® and .
The term eccount was originated by the financial services company Tuxedo Money Solutions, whose products are regulated by the UK Financial Services Authority®.
An eccount can be topped-up with cash at retail outlets, Post Offices®, some bank branches, online by debit or credit card, or by bank transfer and standing order. Wages or salaries can also be paid directly into an eccount.
An eccount offers users a range of features to help them manage their money such as a 24 hour interface from mobile phones, the internet or telephone to access their eccount balance and exchange rates; the ability to move funds to an authorised user’s card; flexibility to set up text alerts; locking and unlocking cards for extra security.
Using a prepaid card (not a debit or credit card) that is issued together with an eccount, funds held can be used to make payments, purchase goods in stores, shop online, buy over the phone or order goods by mail. Cash can also be withdrawn at ATMs throughout the world. Prepaid cards are issued in conjunction with leading international payment networks such as MasterCard® and .
The term eccount was originated by the financial services company Tuxedo Money Solutions, whose products are regulated by the UK Financial Services Authority®.
A fractor is an elementary electronic component, with characteristics of both capacitors and resistors. The fractor is most useful in the field of control, where the phase properties of the fractor help naturally stabilize systems. The fractor was invented during the exploration of materials that show power-law relaxation behavior, such as piezoelectric actuators. The most accurate model for the relaxation behavior turned out to be based in fractional calculus.
The continuous nature of the differintegral allows a control systems designer to select an arbitrary phase angle of the response of their systems. Integer order calculous only allows 90 degree phase shifts, in contrast. Before the invention of the fractor, control systems designers were required to scale a 90 degree phase lag with a 90 degree phase lead, in what is commonly known as a PID controller.
The fractor replaces the ID (integer/derivative) terms of the PID with a single F term of the desired phase.
Principle of Operation
A fractor device depends on the non exponential nature shared by most dielectric materials. The dielectric material used in capacitors are selected to behave in such a way that the exponential model used to predict the behaviour of the devices is accurate. A perfect capacitor is expected to demonstrate an exponential decay in potential when it is discharged through a resistor. Unfortunatly, a perfect capacitor does not exist.
A perfect capacitor would not retain charge after it had been discharged, as can be seen by letting a freshly discharged capacitor sit for some time with its leads insulated from each other. A memory effect within the capacitor can be observed by measuring the voltage on the leads. The precise measurement of the voltage after a varying amount of time is effected by the amount voltage and the duration of time it was applied. This memory effect can be seen much more dramatically in chemical batteries, which are very sensitive to the way in which they are charged.
The memory effect of a fractor is carefully controlled to make an industrially usefully device, i.e. one which behaves consistently. A dielectric material with a desired fractional impedance is applied to roughened conductive plates, which are pressed together to build a capacitor like device. The plates are then clamped together, compressing the dielectric. Subtle performance changes can be seen by varying the pressure applied to the plates.
State of Existence
Only a few fractors have actually ever been made, and they were made by hand. A sample control circuit was designed and built largely from NSF funds. The circuit was used to stabilize a remote spring arm which was operated from a PC joystick. This sample control system known as the "Fractolizer". Unfortunately, after the Fractolizer was constructed and demonstrated at Montana State University to work exactly as expected, all funding for further development was lost. Research continues at Utah State University, in Logan, Utah.
The remaining devices have been tested periodically since their first construction, and most have shown a consistent decline in performance characteristically. Only the few devices that were not sealed after being clamped have stayed somewhat consistent. Ironically, it appears the dielectric reacts more to the glue used to protect the material than the water vapor it meant to defend against.
Publications
AIP Conference Proceedings -- August 3, 2001 -- Volume 582, pp. 175-184
The 11th williamsburg workshop on fundamental physics of ferroelectrics
Fractional Calculus and Biomimetic Control - http://www.csois.usu.edu/people/yqchen/paper/04C16_robio04d.pdf
Links
YanQuan Chen's Group at USU - http://www.ece.usu.edu/csois/people/yqchen/
Fractional Order Control - http://mechatronics.ece.usu.edu/foc/
Digital Fractor in C++ - http://www.cs.montana.edu/~bohannan/Fractor/index.htm
The continuous nature of the differintegral allows a control systems designer to select an arbitrary phase angle of the response of their systems. Integer order calculous only allows 90 degree phase shifts, in contrast. Before the invention of the fractor, control systems designers were required to scale a 90 degree phase lag with a 90 degree phase lead, in what is commonly known as a PID controller.
The fractor replaces the ID (integer/derivative) terms of the PID with a single F term of the desired phase.
Principle of Operation
A fractor device depends on the non exponential nature shared by most dielectric materials. The dielectric material used in capacitors are selected to behave in such a way that the exponential model used to predict the behaviour of the devices is accurate. A perfect capacitor is expected to demonstrate an exponential decay in potential when it is discharged through a resistor. Unfortunatly, a perfect capacitor does not exist.
A perfect capacitor would not retain charge after it had been discharged, as can be seen by letting a freshly discharged capacitor sit for some time with its leads insulated from each other. A memory effect within the capacitor can be observed by measuring the voltage on the leads. The precise measurement of the voltage after a varying amount of time is effected by the amount voltage and the duration of time it was applied. This memory effect can be seen much more dramatically in chemical batteries, which are very sensitive to the way in which they are charged.
The memory effect of a fractor is carefully controlled to make an industrially usefully device, i.e. one which behaves consistently. A dielectric material with a desired fractional impedance is applied to roughened conductive plates, which are pressed together to build a capacitor like device. The plates are then clamped together, compressing the dielectric. Subtle performance changes can be seen by varying the pressure applied to the plates.
State of Existence
Only a few fractors have actually ever been made, and they were made by hand. A sample control circuit was designed and built largely from NSF funds. The circuit was used to stabilize a remote spring arm which was operated from a PC joystick. This sample control system known as the "Fractolizer". Unfortunately, after the Fractolizer was constructed and demonstrated at Montana State University to work exactly as expected, all funding for further development was lost. Research continues at Utah State University, in Logan, Utah.
The remaining devices have been tested periodically since their first construction, and most have shown a consistent decline in performance characteristically. Only the few devices that were not sealed after being clamped have stayed somewhat consistent. Ironically, it appears the dielectric reacts more to the glue used to protect the material than the water vapor it meant to defend against.
Publications
AIP Conference Proceedings -- August 3, 2001 -- Volume 582, pp. 175-184
The 11th williamsburg workshop on fundamental physics of ferroelectrics
Fractional Calculus and Biomimetic Control - http://www.csois.usu.edu/people/yqchen/paper/04C16_robio04d.pdf
Links
YanQuan Chen's Group at USU - http://www.ece.usu.edu/csois/people/yqchen/
Fractional Order Control - http://mechatronics.ece.usu.edu/foc/
Digital Fractor in C++ - http://www.cs.montana.edu/~bohannan/Fractor/index.htm