title: Options for solar thermal and heat recovery loop hybrid system design

authors: Walmsley, Michael R.W.

abstract: Integration of solar thermal energy into low temperature pinch processes, like dairy and food and beverage processes is more economic when combined with a Heat Recovery Loop (HRL) to form a hybrid inter-plant heat recovery system. The hybrid system shares common infrastructure and improves solar heat utilisation through direct solar boosting of the HRL intermediate fluid’s temperature and enthalpy either through parallel or series application. The challenge of dealing with variable solar energy supply is less of a problem in the hybrid system because the HRL with its associated storage acts as an enthalpy buffer which absorbs temperature and flow rate fluctuations on both the heat supply (including solar) and heat demand side simultaneously. Three options for integrating solar thermal directly into HRLs are applied to a large multi-plant dairy case study to demonstrate the hot utility savings potential of the Solar-HRL hybrid system. HRL performance with Variable Temperature Storage (VTS) and solar is dynamically modelled with historical plant data. The series configuration is shown to be consistently better than parallel configuration for the same thermal storage volumes and similar heat exchanger areas.

text: Options for solar thermal and heat recovery loop hybrid system design Integration of solar thermal energy into low temperature pinch processes, like dairy and food and beverage processes is more economic when combined with a Heat Recovery Loop (HRL) to form a hybrid inter-plant heat recovery system. The hybrid system shares common infrastructure and improves solar heat utilisation through direct solar boosting of the HRL intermediate fluid’s temperature and enthalpy either through parallel or series application. The challenge of dealing with variable solar energy supply is less of a problem in the hybrid system because the HRL with its associated storage acts as an enthalpy buffer which absorbs temperature and flow rate fluctuations on both the heat supply (including solar) and heat demand side simultaneously. Three options for integrating solar thermal directly into HRLs are applied to a large multi-plant dairy case study to demonstrate the hot utility savings potential of the Solar-HRL hybrid system. HRL performance with Variable Temperature Storage (VTS) and solar is dynamically modelled with historical plant data. The series configuration is shown to be consistently better than parallel configuration for the same thermal storage volumes and similar heat exchanger areas.

year: 2014-08-31

title: Fabrication of blended chitosan nanofibers by the free surface wire electrospinning

authors: AlJbour, Nawzat D.

abstract: Nanofibers are fibers with diameters in the nanometer range. They are characterized by their high surface area to volume ratio, flexible surface functionalities, and superior mechanical properties. Chitosan is a polycationic polymer which is abundant in nature. Chitosan nanofibers have been widely explored for different potential applications such as wound dressing, tissue engineering, and drug delivery systems. It is difficult to directly spin pure chitosan, due to its high molecular weight, low solubility, and high viscosity. To produce nanofibers, chitosan is commonly blended with other polymers that possess fiber forming capabilities such as polyvinyl alcohol, polycaprolactone, and Polylactic acid. In this study chitosan oligomers of an average molecular weight 15 kDa was blended with the three copolymers at different weight ratios. The fibers were prepared by the free surface wire electrospinning process, and the formed Chitosan nanofibers were characterized by Scanning Electron Microscopy (SEM). SEM results showed that blending chitosan with PLA enhances its spinnability and facilitates uniform and smooth morphology. Blending chitosan with PLA produced nanofibers with better quality, compared to PVA, and PCL.

text: Fabrication of blended chitosan nanofibers by the free surface wire electrospinning Nanofibers are fibers with diameters in the nanometer range. They are characterized by their high surface area to volume ratio, flexible surface functionalities, and superior mechanical properties. Chitosan is a polycationic polymer which is abundant in nature. Chitosan nanofibers have been widely explored for different potential applications such as wound dressing, tissue engineering, and drug delivery systems. It is difficult to directly spin pure chitosan, due to its high molecular weight, low solubility, and high viscosity. To produce nanofibers, chitosan is commonly blended with other polymers that possess fiber forming capabilities such as polyvinyl alcohol, polycaprolactone, and Polylactic acid. In this study chitosan oligomers of an average molecular weight 15 kDa was blended with the three copolymers at different weight ratios. The fibers were prepared by the free surface wire electrospinning process, and the formed Chitosan nanofibers were characterized by Scanning Electron Microscopy (SEM). SEM results showed that blending chitosan with PLA enhances its spinnability and facilitates uniform and smooth morphology. Blending chitosan with PLA produced nanofibers with better quality, compared to PVA, and PCL.

year: 2023-01-01

title: Reducing our prison population: Past failures and new approaches

authors: Tauri, Juan Marcellus

abstract: Earlier this year the Minister of Justice, Andrew Little announced the latest in a long line of reviews, taxpayer-funded summits and inter-agency, ‘wholeof-government’ projects stretching back to the late-1980s, all aimed in some form or other, at making the criminal justice system more ‘safe’ and ‘effective’. Officially launched at a summit held in Porirua in August 2018, the aim of the latest review is to reduce New Zealand’s prison muster by 30% over the next 15 years. And unsurprisingly, given our significant over-representation in prisons, a specific focus of the review is on identifying ways to significantly reduce Māori over-representation in the prison population. This commentary represents a modest offering in response to the current government’s stated aim of making the justice system safer and more effective, and to reduce the prison muster, and it is based on two core arguments, namely that successive governments and the public service have failed to reduce offending and imprisonment and that successful solutions require community empowerment and government/public service accountability.

text: Reducing our prison population: Past failures and new approaches Earlier this year the Minister of Justice, Andrew Little announced the latest in a long line of reviews, taxpayer-funded summits and inter-agency, ‘wholeof-government’ projects stretching back to the late-1980s, all aimed in some form or other, at making the criminal justice system more ‘safe’ and ‘effective’. Officially launched at a summit held in Porirua in August 2018, the aim of the latest review is to reduce New Zealand’s prison muster by 30% over the next 15 years. And unsurprisingly, given our significant over-representation in prisons, a specific focus of the review is on identifying ways to significantly reduce Māori over-representation in the prison population. This commentary represents a modest offering in response to the current government’s stated aim of making the justice system safer and more effective, and to reduce the prison muster, and it is based on two core arguments, namely that successive governments and the public service have failed to reduce offending and imprisonment and that successful solutions require community empowerment and government/public service accountability.

year: 2019