title: Preparation and characterisation of decoloured Novatein and modified PLA blends

authors: Izuchukwu, Sandra C.P.

abstract: Modified Poly (lactic acid) (PLA) was blended with Decoloured Novatein® (DNTP), a thermoplastic protein material using reactive extrusion to produce a degradable material with improved properties compared to neat Decoloured Novatein®. PLA was modified through free radical grafting of itaconic anhydride to create reactive side-chain groups. Varying ratios of DNTP/ PLA-g-IA or PLA were prepared. Blending DNTP with PLA was found to increase tensile strength  between 22% to 538% and modulus between 201 GPa to 3193 GPa, whereas the strain at break decreased between 80% to 94% depending on the blend ratio. The glass transition temperature of the blends which was measured as the tan δ peak, also revealed an increase when compared to neat DNTP.  Scanning electron microscope revealed an enhanced interfacial adhesion between the two phases in the blends with PLA-g-IA suggesting a more homogenous microstructure. WAXS result revealed an insignificant decrease in the crystallinity of the blends compared to neat DNTP, indicating that blending with PLA had no structural effect on DNTP. The results show the possibility and feasibility of blending DNTP with PLA for use in agricultural and packaging applications.

text: Preparation and characterisation of decoloured Novatein and modified PLA blends Modified Poly (lactic acid) (PLA) was blended with Decoloured Novatein® (DNTP), a thermoplastic protein material using reactive extrusion to produce a degradable material with improved properties compared to neat Decoloured Novatein®. PLA was modified through free radical grafting of itaconic anhydride to create reactive side-chain groups. Varying ratios of DNTP/ PLA-g-IA or PLA were prepared. Blending DNTP with PLA was found to increase tensile strength  between 22% to 538% and modulus between 201 GPa to 3193 GPa, whereas the strain at break decreased between 80% to 94% depending on the blend ratio. The glass transition temperature of the blends which was measured as the tan δ peak, also revealed an increase when compared to neat DNTP.  Scanning electron microscope revealed an enhanced interfacial adhesion between the two phases in the blends with PLA-g-IA suggesting a more homogenous microstructure. WAXS result revealed an insignificant decrease in the crystallinity of the blends compared to neat DNTP, indicating that blending with PLA had no structural effect on DNTP. The results show the possibility and feasibility of blending DNTP with PLA for use in agricultural and packaging applications.

year: 2017

title: Online Thermal Analysis of Batch Roasted Coffee Beans

authors: Kelly, Cameron Brian Desmond

subjects: coffee roasting

abstract: We constructed and instrumented a fluidised-bed coffee roaster. This work has been carried out as part of a search for the “ideal point”, which is the point in time when an expert roaster would terminate the roast in order to yield beans that produce the optimal brew. We roasted Costa Rican Arabica beans whilst controlling the roasting temperature to follow a linear ramp. We measured and recorded the input, output, and coffee bean surface temperatures. We introduce the idea of “bean load”, an uncalibrated measure of the heat load presented by the material being roasted. The bean load under constantly-ramping bean surface temperature shows the roast is increasingly endothermic. Toward the end of the roast the endothermic phenomena decrease, or are assisted by exothermic activity. The bean load also has a repeatable dip around first crack. Due to limitations with the roaster we were not able to make reliable measurements at and beyond second crack. We observed no waypoints or events that might be used to pinpoint the “ideal point” to end the roast.

text: Online Thermal Analysis of Batch Roasted Coffee Beans We constructed and instrumented a fluidised-bed coffee roaster. This work has been carried out as part of a search for the “ideal point”, which is the point in time when an expert roaster would terminate the roast in order to yield beans that produce the optimal brew. We roasted Costa Rican Arabica beans whilst controlling the roasting temperature to follow a linear ramp. We measured and recorded the input, output, and coffee bean surface temperatures. We introduce the idea of “bean load”, an uncalibrated measure of the heat load presented by the material being roasted. The bean load under constantly-ramping bean surface temperature shows the roast is increasingly endothermic. Toward the end of the roast the endothermic phenomena decrease, or are assisted by exothermic activity. The bean load also has a repeatable dip around first crack. Due to limitations with the roaster we were not able to make reliable measurements at and beyond second crack. We observed no waypoints or events that might be used to pinpoint the “ideal point” to end the roast.

year: 2014

title: He pūrongo whakahokinga kōrero a te akomanga rūmaki o Te Tohu Paetahi

authors: Nock, Sophie

subjects: Reo Māori

abstract: Ko te whāinga matua o tēnei rangahau he whakakaokao, he wetewete āno hoki i ngā whakahokinga kōrero a te hunga uiui i kake atu ai ki runga i te waka o Te Tohu Paetahi i te tau 2008, i raro i te kōawa o Rehutai, i raro anō hoki i te maru o Te Whare Wānanga o Waikato. Ka aro atu ki ngā urupare a te hunga tekau mā ono mō te kaupapa nei o Te Tohu Paetahi, ka mutu, ka matapakihia ngā kōrero me ngā whakaaro o taua hunga kia āta kitea ai, āe rānei e tika ana te whakahaere, te mahi whakaako i te reo, te tautoko mai hoki a ngā kaiwhakaako me te kura. I te mutunga iho tautoko katoa te hunga uiui ki aua mea katoa.

text: He pūrongo whakahokinga kōrero a te akomanga rūmaki o Te Tohu Paetahi Ko te whāinga matua o tēnei rangahau he whakakaokao, he wetewete āno hoki i ngā whakahokinga kōrero a te hunga uiui i kake atu ai ki runga i te waka o Te Tohu Paetahi i te tau 2008, i raro i te kōawa o Rehutai, i raro anō hoki i te maru o Te Whare Wānanga o Waikato. Ka aro atu ki ngā urupare a te hunga tekau mā ono mō te kaupapa nei o Te Tohu Paetahi, ka mutu, ka matapakihia ngā kōrero me ngā whakaaro o taua hunga kia āta kitea ai, āe rānei e tika ana te whakahaere, te mahi whakaako i te reo, te tautoko mai hoki a ngā kaiwhakaako me te kura. I te mutunga iho tautoko katoa te hunga uiui ki aua mea katoa.

year: 2012-05