title: Moisture sorption and plasticization of bloodmeal-based thermoplastics

authors: Verbeek, Casparus Johan R.

subjects: tri-ethylene glycol

abstract: Sorption characteristics, thermo-mechanical and mechanical properties of bloodmeal-based thermoplastics have been investigated between water activities (aw) of 0.2 and 0.8, using water and tri-ethylene glycol (TEG) as plasticizers. Three different mass ratios of TEG to water were used, 1:1, 1:2 and 5:6 with a total plasticizer content of 60 parts per hundred parts bloodmeal. It was found that the equilibrium moisture content and mechanical properties were highly dependent on relative humidity suggesting that material properties may vary during use. The BET and Flory–Huggins equations gave the best fit for desorption and adsorption, respectively, but a significant difference was observed between adsorption and desorption behaviour below a water activity of 0.6, which was thought to be due to changes in intermolecular interactions. The monolayer adsorption capacity (0.05 g/g) was unaffected by the TEG content, using the BET sorption isotherm. The water activity required to form a monolayer (awl) was also independent of the amount of TEG, but was different for adsorption and desorption (about 0.5 and 0.2, respectively). Increasing TEG did not have a strong influence on the equilibrium moisture content, especially at low water activity. Dynamic mechanical analysis revealed that the glass transition temperature decreased almost linearly with increasing water activity, ranging between 3 and 85 ℃, however, above a water activity of 0.6 a second transition was observed, most likely due to phase separation. Depending of TEG content, tensile strength increased from about 10 to 15 MPa at a water activity of 0.4, where after a drastic decrease was observed. A similar trend was observed for elongation at break. At low water activity (below 0.4) elongation was less than 3%, increasing between 30 and 50% at higher water activities. It was concluded that 10–15 wt% represented a critical point above which mechanical properties becomes very sensitive to the relative humidity of the environment.

text: Moisture sorption and plasticization of bloodmeal-based thermoplastics Sorption characteristics, thermo-mechanical and mechanical properties of bloodmeal-based thermoplastics have been investigated between water activities (aw) of 0.2 and 0.8, using water and tri-ethylene glycol (TEG) as plasticizers. Three different mass ratios of TEG to water were used, 1:1, 1:2 and 5:6 with a total plasticizer content of 60 parts per hundred parts bloodmeal. It was found that the equilibrium moisture content and mechanical properties were highly dependent on relative humidity suggesting that material properties may vary during use. The BET and Flory–Huggins equations gave the best fit for desorption and adsorption, respectively, but a significant difference was observed between adsorption and desorption behaviour below a water activity of 0.6, which was thought to be due to changes in intermolecular interactions. The monolayer adsorption capacity (0.05 g/g) was unaffected by the TEG content, using the BET sorption isotherm. The water activity required to form a monolayer (awl) was also independent of the amount of TEG, but was different for adsorption and desorption (about 0.5 and 0.2, respectively). Increasing TEG did not have a strong influence on the equilibrium moisture content, especially at low water activity. Dynamic mechanical analysis revealed that the glass transition temperature decreased almost linearly with increasing water activity, ranging between 3 and 85 ℃, however, above a water activity of 0.6 a second transition was observed, most likely due to phase separation. Depending of TEG content, tensile strength increased from about 10 to 15 MPa at a water activity of 0.4, where after a drastic decrease was observed. A similar trend was observed for elongation at break. At low water activity (below 0.4) elongation was less than 3%, increasing between 30 and 50% at higher water activities. It was concluded that 10–15 wt% represented a critical point above which mechanical properties becomes very sensitive to the relative humidity of the environment.

year: 2011

title: Scaling of anisotropy in hydromagnetic turbulence

authors: Matthaeus, William H.

subjects: turbulence

abstract: We present evidence that anisotropy of low frequency plasma turbulence scales linearly with the ratio of fluctuating to total magnetic field strength for a useful range of parameters, for incompressible, weakly compressible, and driven magnetohydrodynamic turbulence.

text: Scaling of anisotropy in hydromagnetic turbulence We present evidence that anisotropy of low frequency plasma turbulence scales linearly with the ratio of fluctuating to total magnetic field strength for a useful range of parameters, for incompressible, weakly compressible, and driven magnetohydrodynamic turbulence.

year: 1998

title: Is there evidence that traditional mōteatea (Māori laments) were composed from a common stock of oral formulae?

authors: Roa, Raukura

subjects: New Zealand

abstract: Oral formulaic composition, which involves the use of communally owned formulae of various kinds, is a common feature of verbal arts produced in many different languages. It is particularly associated with pre-literate cultures and tends to be gradually replaced by more individualistic verbal art forms when societies become literate. There are very few publications in which the analysis of mōteatea (Māori laments) is linked explicitly to oral formulaic theory. Nevertheless, there is sufficient evidence in published sources to indicate that traditional mōteatea (defined here as mōteatea that are not fundamentally influenced by European cultural beliefs and practices) exhibit evidence of regularly recurring, conventional themes (such as death, separation, loss and travel) and motifs (such as the setting sun, the presence of rain or mist and sleeplessness). The research reported here set out to test the hypothesis that traditional mōteatea were made up of verbal formulae, that is, of the same or very similar groups of words derived from a common store of poetic resources. Based on the analysis of the mōteatea included in Ngā mōteatea, a collection initially established by Sir Apirana Ngata, I conclude that this hypothesis must be rejected.

text: Is there evidence that traditional mōteatea (Māori laments) were composed from a common stock of oral formulae? Oral formulaic composition, which involves the use of communally owned formulae of various kinds, is a common feature of verbal arts produced in many different languages. It is particularly associated with pre-literate cultures and tends to be gradually replaced by more individualistic verbal art forms when societies become literate. There are very few publications in which the analysis of mōteatea (Māori laments) is linked explicitly to oral formulaic theory. Nevertheless, there is sufficient evidence in published sources to indicate that traditional mōteatea (defined here as mōteatea that are not fundamentally influenced by European cultural beliefs and practices) exhibit evidence of regularly recurring, conventional themes (such as death, separation, loss and travel) and motifs (such as the setting sun, the presence of rain or mist and sleeplessness). The research reported here set out to test the hypothesis that traditional mōteatea were made up of verbal formulae, that is, of the same or very similar groups of words derived from a common store of poetic resources. Based on the analysis of the mōteatea included in Ngā mōteatea, a collection initially established by Sir Apirana Ngata, I conclude that this hypothesis must be rejected.

year: 2007