title: Energy efficiency measures for batch retort sterilization in the food processing industry

authors: Peesel, Ron-Hendrik

abstract: The purpose of this study is to highlight the energy saving potentials of a batch retort sterilization process operated by steam and to develop concepts for improving its energy efficiency. By using the methodical approach of the Onion Diagram and the recovery of low grade heat sources, four comprehensive improved energy efficiency concepts have been developed. Two concepts increase the initial product temperature resulting in lower transient steam consumption rates and a decreased energy demand. The other two options transform the waste heat and the energy for product cooling into heat streams for supplying nearby heat sinks or other processes in the plant. Results show that the total energy demand can be reduced by more than 23 % and 42 % of the energy injected into the system can be recovered. The scope of the study focused on a single, independent retort to ensure the transferability of the concepts. This study also shows, using a practical example, the importance of a comprehensive process understanding and analysis prior to application of Pinch Analysis, which is needed to ensure that the correct waste heat stream temperatures are defined, necessary processing constraints are appreciated, and all possible heat sinks in the process are considered.

text: Energy efficiency measures for batch retort sterilization in the food processing industry The purpose of this study is to highlight the energy saving potentials of a batch retort sterilization process operated by steam and to develop concepts for improving its energy efficiency. By using the methodical approach of the Onion Diagram and the recovery of low grade heat sources, four comprehensive improved energy efficiency concepts have been developed. Two concepts increase the initial product temperature resulting in lower transient steam consumption rates and a decreased energy demand. The other two options transform the waste heat and the energy for product cooling into heat streams for supplying nearby heat sinks or other processes in the plant. Results show that the total energy demand can be reduced by more than 23 % and 42 % of the energy injected into the system can be recovered. The scope of the study focused on a single, independent retort to ensure the transferability of the concepts. This study also shows, using a practical example, the importance of a comprehensive process understanding and analysis prior to application of Pinch Analysis, which is needed to ensure that the correct waste heat stream temperatures are defined, necessary processing constraints are appreciated, and all possible heat sinks in the process are considered.

year: 2016

title: On microstructural evolution and mechanical properties of Ti-5Al-5V-5Mo-3Cr alloy synthesised from elemental powder mixtures

authors: Yang, Fei

subjects: Science & Technology

abstract: In this paper, we explored to prepare a multi-compositional titanium alloy, Ti-5Al-5V-5Mo-3Cr (Ti-5553), by powder compact extrusion from elemental powder mixtures, and investigate the microstructure variation during the synthesising process and after post heat treatments and the changes of mechanical properties. XRD, OM and SEM were used to analyse the phase constitutions and microstructures of the Ti-5553 alloy at different processing conditions, and tensile tests were conducted to examine their mechanical properties. The results showed that a homogeneous Ti-5553 alloy was successfully produced by powder compact extrusion from the powder mixtures, β phase was mainly contained in the hot-pressed and 1200°C-extruded Ti-5553 alloy and had an equiaxed microstructure. Different types of α phase precipitated from the β matrix after heat treatment, and this significantly changed the microstructures and improved the mechanical properties of the extruded Ti-5553 alloy, with yield strength of 1250 MPa and ultimate strength of 1300 MPa for the alloy treated at 675 °C for 2 h, and the ductility of about 6.1% for the alloy treated at 780 °C for 2 h.

text: On microstructural evolution and mechanical properties of Ti-5Al-5V-5Mo-3Cr alloy synthesised from elemental powder mixtures In this paper, we explored to prepare a multi-compositional titanium alloy, Ti-5Al-5V-5Mo-3Cr (Ti-5553), by powder compact extrusion from elemental powder mixtures, and investigate the microstructure variation during the synthesising process and after post heat treatments and the changes of mechanical properties. XRD, OM and SEM were used to analyse the phase constitutions and microstructures of the Ti-5553 alloy at different processing conditions, and tensile tests were conducted to examine their mechanical properties. The results showed that a homogeneous Ti-5553 alloy was successfully produced by powder compact extrusion from the powder mixtures, β phase was mainly contained in the hot-pressed and 1200°C-extruded Ti-5553 alloy and had an equiaxed microstructure. Different types of α phase precipitated from the β matrix after heat treatment, and this significantly changed the microstructures and improved the mechanical properties of the extruded Ti-5553 alloy, with yield strength of 1250 MPa and ultimate strength of 1300 MPa for the alloy treated at 675 °C for 2 h, and the ductility of about 6.1% for the alloy treated at 780 °C for 2 h.

year: 2018

title: How Maori have been affected through the notion and practice of schooling: A theoretical analysis

authors: Williamson, Laurie Thomas

abstract: Education has always been associated according to the public with a necessary function to equip individuals to fit into society when they reach adulthood. The fact that it functions with efficiency is attributed in part to the implementation of social norms, which "impose uniformity of behaviour" (Young 2006, p. 1).

This thesis delves into how Maori have been positioned under a mainstream schooling discourse which has put them at a disadvantage since the implementation of a discourse requires the subjugation of those who are not the majority power holders to assimilate into someone else's discourse. The effect of assimilation into a mainstream discourse has political implications for Maori, as schools are the gateway towards social stratification. This thesis will look at the historical and developmental concept of schooling within a western context, moving towards the development of formal schooling in New Zealand and also look at the sociological and political impact of schooling upon Maori students.

I will also differentiate between the terms schooling and education to suggest Maori forms of educational discourse has been marginalised in favour of assimilation into a supposedly equitable rigid, formal system of schooling. I will illustrate the broader concept of education that takes place outside of schools formal boundaries as a way to contrast the level of control and regulation the government initiates within the formal schooling environment. I will also look at the way schools have been used from its colonial beginnings in New Zealand as a way to civilise or impose one cultural practice on another as a way of breaking down uncivilised beliefs and traditions.

text: How Maori have been affected through the notion and practice of schooling: A theoretical analysis Education has always been associated according to the public with a necessary function to equip individuals to fit into society when they reach adulthood. The fact that it functions with efficiency is attributed in part to the implementation of social norms, which "impose uniformity of behaviour" (Young 2006, p. 1).

This thesis delves into how Maori have been positioned under a mainstream schooling discourse which has put them at a disadvantage since the implementation of a discourse requires the subjugation of those who are not the majority power holders to assimilate into someone else's discourse. The effect of assimilation into a mainstream discourse has political implications for Maori, as schools are the gateway towards social stratification. This thesis will look at the historical and developmental concept of schooling within a western context, moving towards the development of formal schooling in New Zealand and also look at the sociological and political impact of schooling upon Maori students.

I will also differentiate between the terms schooling and education to suggest Maori forms of educational discourse has been marginalised in favour of assimilation into a supposedly equitable rigid, formal system of schooling. I will illustrate the broader concept of education that takes place outside of schools formal boundaries as a way to contrast the level of control and regulation the government initiates within the formal schooling environment. I will also look at the way schools have been used from its colonial beginnings in New Zealand as a way to civilise or impose one cultural practice on another as a way of breaking down uncivilised beliefs and traditions.

year: 2012