title: Rheology and Processing of Novatein Thermoplastic Protein

authors: Mohan, Velram Balaji

subjects: Rheology

abstract: Biopolymers have become suitable alternatives to petro-chemical polymers as they can biodegrade and are considered environmentally friendly. Novatein Thermoplastic Protein (NTP) is a newly developed plastic material using bovine bloodmeal. Knowledge of the rheology of NTP is required to assess processability and to optimise process design. The objective of this research was to use capillary rheometry and batch mixing to determine the rheology and processing behaviour of NTP. These were evaluated at constant plasticiser content, but using three different ratios of water to plasticiser (triethylene glycol, TEG). Each of these was evaluated at 115, 120 and 125 °C. It was shown that NTP is a non-Newtonian, shear thinning fluid with similar behaviour compared to linear low density polyethylene. It was found that viscosity is highly dependent on water content; decreasing with increasing water content. At a shear rate of 15 s-1, the apparent viscosity for the standard formulation (60 parts water per hundred parts bloodmeal) was 2000 Pa.s compared to 7000 Pa.s for the formulation containing 30 parts water [water (30) : TEG (30)], measured at 115 °C. Viscosity decreased slightly with increasing temperature and the degree of non-Newtonian behaviour was mostly unaffected by temperature. The flow behaviour index, n, was found to be in the range 0.11 to 0.17, with no discernable temperature dependence. In the standard formulation, the total amount of plasticiser and ratio water to TEG was higher, which resulted in different flow behaviour with respect to temperature. Batch mixing was used to determine the processing window (∆t) by monitoring torque changes over time during mixing. Processing window for standard NTP decreased from 260 to 220 seconds when the mixing speed was increased from 75 to 95 RPM. The processing window was shortened with reducing water content or an increase in temperature. At 125 °C and 95 RPM the processing window was only 67 seconds for the formulation with 30 parts water and 30 parts TEG. It was concluded that crosslinking was accelerated with an increase in shear and temperature or a reduction in moisture content. Thermal or mechanical energy activates crosslinking, while water plasticises the polymer which decreases the rate of crosslinking. Processing NTP required a delicate balance of supplying enough mechanical and thermal energy for chain rearrangement and consolidation, but preventing fast crosslinking. Crosslinking can be retarded using larger amounts of water, but excessive water may lead to problems after product moulding. Replacing water with TEG does not prevent crosslinking, but does lower the apparent viscosity during processing.

text: Rheology and Processing of Novatein Thermoplastic Protein Biopolymers have become suitable alternatives to petro-chemical polymers as they can biodegrade and are considered environmentally friendly. Novatein Thermoplastic Protein (NTP) is a newly developed plastic material using bovine bloodmeal. Knowledge of the rheology of NTP is required to assess processability and to optimise process design. The objective of this research was to use capillary rheometry and batch mixing to determine the rheology and processing behaviour of NTP. These were evaluated at constant plasticiser content, but using three different ratios of water to plasticiser (triethylene glycol, TEG). Each of these was evaluated at 115, 120 and 125 °C. It was shown that NTP is a non-Newtonian, shear thinning fluid with similar behaviour compared to linear low density polyethylene. It was found that viscosity is highly dependent on water content; decreasing with increasing water content. At a shear rate of 15 s-1, the apparent viscosity for the standard formulation (60 parts water per hundred parts bloodmeal) was 2000 Pa.s compared to 7000 Pa.s for the formulation containing 30 parts water [water (30) : TEG (30)], measured at 115 °C. Viscosity decreased slightly with increasing temperature and the degree of non-Newtonian behaviour was mostly unaffected by temperature. The flow behaviour index, n, was found to be in the range 0.11 to 0.17, with no discernable temperature dependence. In the standard formulation, the total amount of plasticiser and ratio water to TEG was higher, which resulted in different flow behaviour with respect to temperature. Batch mixing was used to determine the processing window (∆t) by monitoring torque changes over time during mixing. Processing window for standard NTP decreased from 260 to 220 seconds when the mixing speed was increased from 75 to 95 RPM. The processing window was shortened with reducing water content or an increase in temperature. At 125 °C and 95 RPM the processing window was only 67 seconds for the formulation with 30 parts water and 30 parts TEG. It was concluded that crosslinking was accelerated with an increase in shear and temperature or a reduction in moisture content. Thermal or mechanical energy activates crosslinking, while water plasticises the polymer which decreases the rate of crosslinking. Processing NTP required a delicate balance of supplying enough mechanical and thermal energy for chain rearrangement and consolidation, but preventing fast crosslinking. Crosslinking can be retarded using larger amounts of water, but excessive water may lead to problems after product moulding. Replacing water with TEG does not prevent crosslinking, but does lower the apparent viscosity during processing.

year: 2010

title: Graph-RAT programming environment

authors: McEnnis, Daniel

subjects: computer science

abstract: Graph-RAT is a new programming environment specializing in relational data mining. It incorporates a number of different techniques into a single framework for data collection, data cleaning, propositionalization, and analysis. The language is functional where algorithms are executed over arbitrary sub-graphs of the data. Analytical results can be conducted using collaborative filtering or machine learning techniques. The example algorithms are under BSD license.

text: Graph-RAT programming environment Graph-RAT is a new programming environment specializing in relational data mining. It incorporates a number of different techniques into a single framework for data collection, data cleaning, propositionalization, and analysis. The language is functional where algorithms are executed over arbitrary sub-graphs of the data. Analytical results can be conducted using collaborative filtering or machine learning techniques. The example algorithms are under BSD license.

year: 2009-08-12

title: Using Twitter in an Indigenous language: An analysis of te reo Māori tweets

authors: Keegan, Te Taka Adrian Gregory

abstract: Language revitalization theory suggests that one way to improve the health of a language is to increase the number of domains where the language is used. Social network platforms provide a variety of domains where indigenous- language communities are able to communicate in their own languages. Although the capability exists, is social networking being used by indigenous- language communities? This paper reports on one particular social networking platform, Twitter, by using two separate methodologies. First, Twitter statistics collated from the Indigenous Tweets website are analysed. The data show that languages such as Basque, Haitian Creole, Welsh, Irish Gaelic, Frisian and Kapampangan do have a presence in the “Twittersphere”. Further analysis for te reo Māori (the Māori language) shows that tweets in te reo Māori are rising and peak when certain events occur. The second methodology involved gathering empirical data by tweeting in te reo Māori. This served two purposes: it allowed an ancillary check on the validity of the Indigenous Tweets data and it allowed the opportunity to determine if the number of indigenous- language tweets could be influenced by the actions of one tweeter.

text: Using Twitter in an Indigenous language: An analysis of te reo Māori tweets Language revitalization theory suggests that one way to improve the health of a language is to increase the number of domains where the language is used. Social network platforms provide a variety of domains where indigenous- language communities are able to communicate in their own languages. Although the capability exists, is social networking being used by indigenous- language communities? This paper reports on one particular social networking platform, Twitter, by using two separate methodologies. First, Twitter statistics collated from the Indigenous Tweets website are analysed. The data show that languages such as Basque, Haitian Creole, Welsh, Irish Gaelic, Frisian and Kapampangan do have a presence in the “Twittersphere”. Further analysis for te reo Māori (the Māori language) shows that tweets in te reo Māori are rising and peak when certain events occur. The second methodology involved gathering empirical data by tweeting in te reo Māori. This served two purposes: it allowed an ancillary check on the validity of the Indigenous Tweets data and it allowed the opportunity to determine if the number of indigenous- language tweets could be influenced by the actions of one tweeter.

year: 2015