title: Investigation into low power active electromagnetic damping for automotive applications

authors: Fow, Alista John

subjects: Electromagnetic

abstract: Automobile suspension systems carry out two important functions; road handling and passenger comfort. Hydraulic passive dampers are the most common system employed on vehicles, yet it is well known that passive suspension systems are less effective on lightweight vehicles. Modern damper technologies such as semi-active and active dampers, offer potential benefits when used in these vehicles. An active
electromagnetic (e.m.) damper could offer these same benefits with lower power consumption and with less mechanical complexity than existing active suspension systems. This research investigates the effectiveness of e.m. passive and active damping on the performance of lightweight electric vehicles and develops a novel, fully integrated model of the e.m. damper in both passive and active modes.
    The proposed e.m. damper consisted of one or more cylindrical permanent magnets that travelled axially through one or more cylindrical solenoids. A magnet/solenoid damper system was modelled for both the passive and active modes. The magnets were modelled as a current carrying solenoid and from Maxwell's Laws the magnetic field was determined. For the passive damper, the magnetic field was used with Faraday's Law to determine the forces generated. In the case of the active damper the magnetic field and the current in the damper solenoid were used to calculate the magnetic force.
     Both a passive and active e.m. damper were modelled for a small, one degree  of freedom experimental system. The active e.m. damper was modelled as a pure Skyhook damper. There was a good correlation between the modelled and experimental data for the magnet, the passive and the active Skyhook dampers. The passive damper model was scaled up as a two degree of freedom system using realistic values for a road legal lightweight electric vehicle and demonstrated that sufficient passive damping could be achieved for automotive uses, but at the price of excessive mass. For the scaled up active damper model, sufficient force could be achieved with a mass similar to a commercial hydraulic damper. The power consumption was less than 5 % of an equivalent active hydraulic suspension system. 
     This demonstrated that the passive damper was currently impractical for lightweight electric vehicles, but the active electromagnetic damper was of sufficiently low weight and power consumption: had enough authority and offered sufficient passenger comfort benefits to include in future lightweight electric vehicle designs.

text: Investigation into low power active electromagnetic damping for automotive applications Automobile suspension systems carry out two important functions; road handling and passenger comfort. Hydraulic passive dampers are the most common system employed on vehicles, yet it is well known that passive suspension systems are less effective on lightweight vehicles. Modern damper technologies such as semi-active and active dampers, offer potential benefits when used in these vehicles. An active
electromagnetic (e.m.) damper could offer these same benefits with lower power consumption and with less mechanical complexity than existing active suspension systems. This research investigates the effectiveness of e.m. passive and active damping on the performance of lightweight electric vehicles and develops a novel, fully integrated model of the e.m. damper in both passive and active modes.
    The proposed e.m. damper consisted of one or more cylindrical permanent magnets that travelled axially through one or more cylindrical solenoids. A magnet/solenoid damper system was modelled for both the passive and active modes. The magnets were modelled as a current carrying solenoid and from Maxwell's Laws the magnetic field was determined. For the passive damper, the magnetic field was used with Faraday's Law to determine the forces generated. In the case of the active damper the magnetic field and the current in the damper solenoid were used to calculate the magnetic force.
     Both a passive and active e.m. damper were modelled for a small, one degree  of freedom experimental system. The active e.m. damper was modelled as a pure Skyhook damper. There was a good correlation between the modelled and experimental data for the magnet, the passive and the active Skyhook dampers. The passive damper model was scaled up as a two degree of freedom system using realistic values for a road legal lightweight electric vehicle and demonstrated that sufficient passive damping could be achieved for automotive uses, but at the price of excessive mass. For the scaled up active damper model, sufficient force could be achieved with a mass similar to a commercial hydraulic damper. The power consumption was less than 5 % of an equivalent active hydraulic suspension system. 
     This demonstrated that the passive damper was currently impractical for lightweight electric vehicles, but the active electromagnetic damper was of sufficiently low weight and power consumption: had enough authority and offered sufficient passenger comfort benefits to include in future lightweight electric vehicle designs.

year: 2015

title: Structure, light & temperature induced changes in the compound eyes of Antarctic crustaceans

authors: Tiang, Kin Ming

abstract: The structure of the photoreceptors of three different Antarctic crustaceans was investigated by light and electron microscopy. Special attention was paid to light and temperature induced changes of the normal, i.e. dark-adapted eye. 
The apposition eye of Orchomene plebs shows structural modifications which are interpreted as adaptations to maximise photon capture in an environment of low ambient light intensities. Dark-light adaptational changes affect the position of the screening pigment granules, the volume of the random and the composition and density of the organelles in both retinula and interstitial cells. Exposure to a temperature of +10°c for seven hours affects the structural integrity of the rhabdoms and mimicks light-adaptation in animals that are kept in the dark. Rhabdoms regenerate as long as the animals are returned to water of 0°C.
The ommatidia of the dorsal eye of Glyptonotus antarcticus possess very large diameters and are of the apposition type. Dark-light adaptational changes, which are confined to the dark eye if one eye is painted black and the other is left untouched, involve radial migration of screening pigment granules in the retinula cells surrounding the rhabdom. An elevation of the temperature also affects the position of the screening pigments, but the rhabdom ultrastructure is far less affected than that of Orchomene plebs. 
The compound eyes of the Ross Ice Shelf amphipod Orchomene grandis show the highest degree of structural adaptation to a dimly-lit environment. Following exposure to sunlight or darkness for one week at a temperature of approximately +1°C. the extraordinarily massive rhabdoms exhibit almost total disintegration. The density of screening pigment granules is so low that migrations upon dark-light adaptation are insignificant. The eye of Orchornene grandis shows the smallest capacity of all three species studied to adapt to different ambient light levels.

text: Structure, light & temperature induced changes in the compound eyes of Antarctic crustaceans The structure of the photoreceptors of three different Antarctic crustaceans was investigated by light and electron microscopy. Special attention was paid to light and temperature induced changes of the normal, i.e. dark-adapted eye. 
The apposition eye of Orchomene plebs shows structural modifications which are interpreted as adaptations to maximise photon capture in an environment of low ambient light intensities. Dark-light adaptational changes affect the position of the screening pigment granules, the volume of the random and the composition and density of the organelles in both retinula and interstitial cells. Exposure to a temperature of +10°c for seven hours affects the structural integrity of the rhabdoms and mimicks light-adaptation in animals that are kept in the dark. Rhabdoms regenerate as long as the animals are returned to water of 0°C.
The ommatidia of the dorsal eye of Glyptonotus antarcticus possess very large diameters and are of the apposition type. Dark-light adaptational changes, which are confined to the dark eye if one eye is painted black and the other is left untouched, involve radial migration of screening pigment granules in the retinula cells surrounding the rhabdom. An elevation of the temperature also affects the position of the screening pigments, but the rhabdom ultrastructure is far less affected than that of Orchomene plebs. 
The compound eyes of the Ross Ice Shelf amphipod Orchomene grandis show the highest degree of structural adaptation to a dimly-lit environment. Following exposure to sunlight or darkness for one week at a temperature of approximately +1°C. the extraordinarily massive rhabdoms exhibit almost total disintegration. The density of screening pigment granules is so low that migrations upon dark-light adaptation are insignificant. The eye of Orchornene grandis shows the smallest capacity of all three species studied to adapt to different ambient light levels.

year: 1980

title: A cultural encounter through volunteer tourism: Towards the ideals of sustainable tourism?

authors: McIntosh, Alison J.

subjects: cultural tourism

abstract: International volunteering is increasingly recognised as a form of alternative tourism. However, the nature of the ‘alternative’ experience gained, and the ensuing narrative between host and volunteer, remains under-explored in published research, especially in volunteer tourism research within a cultural context in a developed nation. This paper examines the nexus between volunteer tourism and cultural tourism in the search for alternative and sustainable experiences through tourism. Qualitative research using in-depth interviews, diaries and participant observation was conducted to examine the pre-, during and post-trip experiences of 12 Australian visitors undertaking organised volunteer activities in an indigenous Maori community in the North Island of New Zealand during January 2005. Members of the indigenous Maori community were also interviewed to provide an important host perspective. Findings suggest that the nature of the interaction and cultural experiences gained were perceived as mutually beneficial and seemingly different from those gained from traditional cultural products. In particular, the volunteers experienced an alternative Maori cultural product and engaged in a different narrative with their Maori hosts through their volunteer work, one rich in authentic cultural content, genuine and reflective of modern Maori life in New Zealand society.

text: A cultural encounter through volunteer tourism: Towards the ideals of sustainable tourism? International volunteering is increasingly recognised as a form of alternative tourism. However, the nature of the ‘alternative’ experience gained, and the ensuing narrative between host and volunteer, remains under-explored in published research, especially in volunteer tourism research within a cultural context in a developed nation. This paper examines the nexus between volunteer tourism and cultural tourism in the search for alternative and sustainable experiences through tourism. Qualitative research using in-depth interviews, diaries and participant observation was conducted to examine the pre-, during and post-trip experiences of 12 Australian visitors undertaking organised volunteer activities in an indigenous Maori community in the North Island of New Zealand during January 2005. Members of the indigenous Maori community were also interviewed to provide an important host perspective. Findings suggest that the nature of the interaction and cultural experiences gained were perceived as mutually beneficial and seemingly different from those gained from traditional cultural products. In particular, the volunteers experienced an alternative Maori cultural product and engaged in a different narrative with their Maori hosts through their volunteer work, one rich in authentic cultural content, genuine and reflective of modern Maori life in New Zealand society.

year: 2007