title: Comparison of dynamic properties of magnetorheological elastomers with existing antivibration rubbers

authors: Shuib, Raa Khimi

subjects: Science & Technology

abstract: Tan δ and energy dissipated during hysteresis testing of isotropic and anisotropic MREs containing silane modified iron sand particles in a natural rubber matrix were compared with existing antivibration rubbers. Tan δ was measured using dynamic mechanical analysis (DMA) over a range of frequency (0.01–130 Hz), strain amplitude (0.1–4.5%), and temperature (−100–50 °C). Energy dissipated was measured using a universal tester under cyclic tensile loading. The chosen antivibration rubbers for comparison contained different contents of carbon black filler (30, 50 and 70 phr) in a natural rubber matrix. It was found that energy absorption for comparative samples was generally higher than isotropic and anisotropic MREs over the range of frequency and strain amplitude explored, as well as in hysteresis testing and this was believed to be largely due the presence of carbon black in the formulation. Further assessment was carried out on materials that were the same as anisotropic MREs except they had additions of carbon black. The energy absorption was found higher than comparative samples with the same carbon black contents, supporting the use of iron sand to improve damping. However, trends for energy absorption at around Tg were found to reverse which is considered to be due to the segmental motion of rubber chains being by far the most significant influence on energy absorption in the glass transition zone.

text: Comparison of dynamic properties of magnetorheological elastomers with existing antivibration rubbers Tan δ and energy dissipated during hysteresis testing of isotropic and anisotropic MREs containing silane modified iron sand particles in a natural rubber matrix were compared with existing antivibration rubbers. Tan δ was measured using dynamic mechanical analysis (DMA) over a range of frequency (0.01–130 Hz), strain amplitude (0.1–4.5%), and temperature (−100–50 °C). Energy dissipated was measured using a universal tester under cyclic tensile loading. The chosen antivibration rubbers for comparison contained different contents of carbon black filler (30, 50 and 70 phr) in a natural rubber matrix. It was found that energy absorption for comparative samples was generally higher than isotropic and anisotropic MREs over the range of frequency and strain amplitude explored, as well as in hysteresis testing and this was believed to be largely due the presence of carbon black in the formulation. Further assessment was carried out on materials that were the same as anisotropic MREs except they had additions of carbon black. The energy absorption was found higher than comparative samples with the same carbon black contents, supporting the use of iron sand to improve damping. However, trends for energy absorption at around Tg were found to reverse which is considered to be due to the segmental motion of rubber chains being by far the most significant influence on energy absorption in the glass transition zone.

year: 2015-12-15

title: Thermonema lapsum gen. nov., sp. nov., a Thermophilic Gliding Bacterium

authors: Hudson, J. Andrew

subjects: biology

abstract: We previously reported the isolation of five strains of a thermophilic gliding organism. These strains are described here as a new genus and species, Thermonema lapsum. The isolates can be readily distinguished from other thermophilic gliding bacteria as they are apparently unicellular aerobic filaments that grow optimally at 60°C. Their cell walls are similar in ultrastructure to those of gram-negative cells, but they are susceptible to penicillin G. Our isolates can be grown on a fully defined medium containing amino acids. Oxidation-versus-fermentation tests indicate that deamination takes place. The type strain, strain 23/9, has been deposited with the American Type Culture Collection as strain ATCC 43542.

text: Thermonema lapsum gen. nov., sp. nov., a Thermophilic Gliding Bacterium We previously reported the isolation of five strains of a thermophilic gliding organism. These strains are described here as a new genus and species, Thermonema lapsum. The isolates can be readily distinguished from other thermophilic gliding bacteria as they are apparently unicellular aerobic filaments that grow optimally at 60°C. Their cell walls are similar in ultrastructure to those of gram-negative cells, but they are susceptible to penicillin G. Our isolates can be grown on a fully defined medium containing amino acids. Oxidation-versus-fermentation tests indicate that deamination takes place. The type strain, strain 23/9, has been deposited with the American Type Culture Collection as strain ATCC 43542.

year: 1989

title: Maori sustainable development in the 21st Century: The importance of Maori values, strategic planning and information systems

authors: Harmsworth, Garth

subjects: Development studies

abstract: The term ‘sustainable development’ has been widely used since the latter part of the 20th century. The concept implies economic and social development, economic growth, and environmental responsibility in order to sustain improved standards of living based on economic growth, to achieve some form of social equity, and to manage the environment in a sustainable way. Sustainable development should generally be at a rate that allows future generations to meet their needs without causing degradation of the natural environment, and should avoid economic or social decay. The concept has been debated and criticised by many as being ambiguous, untenable, and difficult to achieve, and frequently labelled part of global capitalism. But the concept provides a challenge to all of us, on how to balance economic, social, and cultural goals, while at the same time safeguarding and responsibly managing the environment for future generations. Attempts by indigenous peoples internationally to achieve sustainable development have been based on holistic approaches and frameworks that seek to balance economic, social, cultural and environmental objectives, and these provide effective models for viable sustainable development approaches. Māori Sustainable Development in Aotearoa-New Zealand is a term often used to describe a pathway to Māori autonomy, self-determination, the building of human and social capacity, as part of a strategic direction to capitalise on opportunities in the 21st century. This paper outlines research undertaken between 1998 and 2002 and funded by the Foundation for Research, Science, and Technology (FRST) in the programme “Māori Sustainable Development in Te Puku o Te Ika”, contract UOWX0005, simply referred to as the MSD programme. It focuses on the importance of determining Māori values, a vision, strategic planning and development of information systems as a holistic framework and process method to achieve Māori sustainable development.

text: Maori sustainable development in the 21st Century: The importance of Maori values, strategic planning and information systems The term ‘sustainable development’ has been widely used since the latter part of the 20th century. The concept implies economic and social development, economic growth, and environmental responsibility in order to sustain improved standards of living based on economic growth, to achieve some form of social equity, and to manage the environment in a sustainable way. Sustainable development should generally be at a rate that allows future generations to meet their needs without causing degradation of the natural environment, and should avoid economic or social decay. The concept has been debated and criticised by many as being ambiguous, untenable, and difficult to achieve, and frequently labelled part of global capitalism. But the concept provides a challenge to all of us, on how to balance economic, social, and cultural goals, while at the same time safeguarding and responsibly managing the environment for future generations. Attempts by indigenous peoples internationally to achieve sustainable development have been based on holistic approaches and frameworks that seek to balance economic, social, cultural and environmental objectives, and these provide effective models for viable sustainable development approaches. Māori Sustainable Development in Aotearoa-New Zealand is a term often used to describe a pathway to Māori autonomy, self-determination, the building of human and social capacity, as part of a strategic direction to capitalise on opportunities in the 21st century. This paper outlines research undertaken between 1998 and 2002 and funded by the Foundation for Research, Science, and Technology (FRST) in the programme “Māori Sustainable Development in Te Puku o Te Ika”, contract UOWX0005, simply referred to as the MSD programme. It focuses on the importance of determining Māori values, a vision, strategic planning and development of information systems as a holistic framework and process method to achieve Māori sustainable development.

year: 2002