title: Degradation as a result of UV radiation of bloodmeal-based thermoplastics

authors: Verbeek, Casparus Johan R.

subjects: bloodmeal

abstract: Polymers are known for their susceptibility to degradation as a result of ultra-violet (UV) radiation. In this study, the UV stability of bloodmeal-based thermoplastics (BMT) was evaluated over a period of 12 weeks. Formulations with and without plasticiser were tested and moisture was excluded during accelerated weathering to isolate the effect of UV because of the material’s known sensitivity to moisture. It was found that embrittlement due to loss of water overshadowed the effect of UV degradation. Embrittlement caused the material’s toughness to be reduced by an order of magnitude after only two weeks of exposure, for either plasticised or unplasticised samples. An initial increase in tensile strength was observed after two weeks followed by a steady decline in strength. The elastic modulus reached a plateau after about two weeks of exposure. FTIR did not confirm any chemical changes after 12 weeks exposure and TGA suggested that low molecular mass species were quickly lost during the course of the test. The absence of chemical changes does not suggest resistance to environmental degradation, although the dark pigmentation of bloodmeal may have contributed to the lack of UV degradation. Embrittlement remains a greater concern and requires further attention.

text: Degradation as a result of UV radiation of bloodmeal-based thermoplastics Polymers are known for their susceptibility to degradation as a result of ultra-violet (UV) radiation. In this study, the UV stability of bloodmeal-based thermoplastics (BMT) was evaluated over a period of 12 weeks. Formulations with and without plasticiser were tested and moisture was excluded during accelerated weathering to isolate the effect of UV because of the material’s known sensitivity to moisture. It was found that embrittlement due to loss of water overshadowed the effect of UV degradation. Embrittlement caused the material’s toughness to be reduced by an order of magnitude after only two weeks of exposure, for either plasticised or unplasticised samples. An initial increase in tensile strength was observed after two weeks followed by a steady decline in strength. The elastic modulus reached a plateau after about two weeks of exposure. FTIR did not confirm any chemical changes after 12 weeks exposure and TGA suggested that low molecular mass species were quickly lost during the course of the test. The absence of chemical changes does not suggest resistance to environmental degradation, although the dark pigmentation of bloodmeal may have contributed to the lack of UV degradation. Embrittlement remains a greater concern and requires further attention.

year: 2011

title: Development of an Intraruminal Controlled-Release Device

authors: McLellan, Bradley John

subjects: gas-producing cell

abstract: Slow-release devices retained in the rumen, are a simple method for continuous administration of bioactives to ruminant animals.  To satisfy regulatory requirements and avoid waste of bioactive due to under- or over-dosing, it is advantageous to have a constant and predictable release rate.  Existing intraruminal controlled-release technologies cannot easily be adapted for different bioactives or rates of release and can be influenced by the variable physiological environment in the rumen.  Some existing commercial products use the pressure generated by a hydrogen gas-producing cell to extrude fluids from a syringe-like device.  This technology may provide advantages for ruminal controlled-release as the gas production rate is unaffected by environment in the rumen and can be easily adjusted using electrical resistance applied to the gas cell.  This technology was adapted for use in the rumen in these studies.
Initial experiments identified the need for greater understanding of the rate that hydrogen is produced by the gas cell and the rate that gas diffuses through the barrel walls.  Gas production rate was found to be inversely proportional to the resistance applied to the gas-producing cell.  Factors affecting gas diffusion rate from the device were studied and a polymer was identified that reduced hydrogen diffusion to 5% of that for the initial components used.  A relationship was developed to predict the release profile of a device.  Controlled-release devices were constructed from selected materials.  They released blank formulation at in vitro at a constant rate, which was within experimental variation of predicted values.  Release rates from the devices used in vivo were slightly higher than predicted.  The presence of rumen gases inside in vivo devices suggested that the difference may be due to inward diffusion of these gases; these may be eliminated by further study of barrel materials.  Recommendations on the redesign of this technology for use as a generic intraruminal delivery system are given.

text: Development of an Intraruminal Controlled-Release Device Slow-release devices retained in the rumen, are a simple method for continuous administration of bioactives to ruminant animals.  To satisfy regulatory requirements and avoid waste of bioactive due to under- or over-dosing, it is advantageous to have a constant and predictable release rate.  Existing intraruminal controlled-release technologies cannot easily be adapted for different bioactives or rates of release and can be influenced by the variable physiological environment in the rumen.  Some existing commercial products use the pressure generated by a hydrogen gas-producing cell to extrude fluids from a syringe-like device.  This technology may provide advantages for ruminal controlled-release as the gas production rate is unaffected by environment in the rumen and can be easily adjusted using electrical resistance applied to the gas cell.  This technology was adapted for use in the rumen in these studies.
Initial experiments identified the need for greater understanding of the rate that hydrogen is produced by the gas cell and the rate that gas diffuses through the barrel walls.  Gas production rate was found to be inversely proportional to the resistance applied to the gas-producing cell.  Factors affecting gas diffusion rate from the device were studied and a polymer was identified that reduced hydrogen diffusion to 5% of that for the initial components used.  A relationship was developed to predict the release profile of a device.  Controlled-release devices were constructed from selected materials.  They released blank formulation at in vitro at a constant rate, which was within experimental variation of predicted values.  Release rates from the devices used in vivo were slightly higher than predicted.  The presence of rumen gases inside in vivo devices suggested that the difference may be due to inward diffusion of these gases; these may be eliminated by further study of barrel materials.  Recommendations on the redesign of this technology for use as a generic intraruminal delivery system are given.

year: 2007

title: How usable is a smartphone with a Māori-language interface?

authors: Mato, Paora James

subjects: Mäori

abstract: Major languages dominate contemporary technologies. For Mäori, there is opportunity to engage with some technologies using their language and to participate within Mäori- language communities in various digital media. A smartphone launched by Two Degrees Mobile Limited provides a Mäori- language interface option. An initial pilot study indicated users will engage with this interface, but when pushed for time will switch the interface to the English- language option. This paper reports on a study undertaken to test the usability of the smartphone Mäorilanguage interface. Participants reported diffi culties and some frustration as they struggled with new words and unfamiliar uses of words. They also expressed disappointment at poor translations and arbitrary truncations. The feedback highlights perceived shortcomings encountered when technologies that are normally developed and used in a major language are translated for use in minority Indigenous languages. Mäori-language strategies that consider using translated application interfaces should be cognisant of such issues.

text: How usable is a smartphone with a Māori-language interface? Major languages dominate contemporary technologies. For Mäori, there is opportunity to engage with some technologies using their language and to participate within Mäori- language communities in various digital media. A smartphone launched by Two Degrees Mobile Limited provides a Mäori- language interface option. An initial pilot study indicated users will engage with this interface, but when pushed for time will switch the interface to the English- language option. This paper reports on a study undertaken to test the usability of the smartphone Mäorilanguage interface. Participants reported diffi culties and some frustration as they struggled with new words and unfamiliar uses of words. They also expressed disappointment at poor translations and arbitrary truncations. The feedback highlights perceived shortcomings encountered when technologies that are normally developed and used in a major language are translated for use in minority Indigenous languages. Mäori-language strategies that consider using translated application interfaces should be cognisant of such issues.

year: 2016