title: The effect of flotation cell shape on deinking behaviour

authors: Jones, Lewis

subjects: engineering

abstract: Studies were undertaken to investigate the deinking behaviour of different shaped deinking cells of the same volume. For comparative purposes, most oprational variables were kept constant, and the same injector was used throughout the study. The position of the injector, however, was varied in some cases to go along with the particular cell shape being studied. 

Three types of cell shapes were studied, (1) cylindrical with tangential air injection, (2) rectanular with vertical injection, and (3) rectangular with horizontal injection. Eucalyptus/toner slurries and news/mag wastepaper slurries were deinked. Flow patterns in the cells and the corresponding deinking efficiencies were measured. 

It was found that strong and excessive re-circulatory flows within the cells could under certain conditions be a major factor in reducing brightness lift. Vertical injection into a rectangular cell gave stable flow patterns, non-wavy froth removal and sustained brightness lift for a wide range of feed and airflow rates. Horizontal injection into a similar rectangular shaped cell exhibited quite different characteristics. High brightness lift was possible for certain conditions and not for others. Wavy froth and excessive recirculation flow patterns varied with feed and airflow. The cylindrical cell with tangential injection gave stable circulatory flow and stable froth removal at low flow rates but was unable to deink at high flows.

text: The effect of flotation cell shape on deinking behaviour Studies were undertaken to investigate the deinking behaviour of different shaped deinking cells of the same volume. For comparative purposes, most oprational variables were kept constant, and the same injector was used throughout the study. The position of the injector, however, was varied in some cases to go along with the particular cell shape being studied. 

Three types of cell shapes were studied, (1) cylindrical with tangential air injection, (2) rectanular with vertical injection, and (3) rectangular with horizontal injection. Eucalyptus/toner slurries and news/mag wastepaper slurries were deinked. Flow patterns in the cells and the corresponding deinking efficiencies were measured. 

It was found that strong and excessive re-circulatory flows within the cells could under certain conditions be a major factor in reducing brightness lift. Vertical injection into a rectangular cell gave stable flow patterns, non-wavy froth removal and sustained brightness lift for a wide range of feed and airflow rates. Horizontal injection into a similar rectangular shaped cell exhibited quite different characteristics. High brightness lift was possible for certain conditions and not for others. Wavy froth and excessive recirculation flow patterns varied with feed and airflow. The cylindrical cell with tangential injection gave stable circulatory flow and stable froth removal at low flow rates but was unable to deink at high flows.

year: 2001

title: Flow clustering using machine learning techniques

authors: McGregor, Anthony James

subjects: Science & Technology

abstract: Packet header traces are widely used in network analysis. Header traces are the aggregate of traffic from many concurrent applications. We present a methodology, based on machine learning, that can break the trace down into clusters of traffic where each cluster has different traffic characteristics. Typical clusters include bulk transfer, single and multiple transactions and interactive traffic, amongst others. The paper includes a description of the methodology, a visualisation of the attribute statistics that aids in recognising cluster types and a discussion of the stability and effectiveness of the methodology.

text: Flow clustering using machine learning techniques Packet header traces are widely used in network analysis. Header traces are the aggregate of traffic from many concurrent applications. We present a methodology, based on machine learning, that can break the trace down into clusters of traffic where each cluster has different traffic characteristics. Typical clusters include bulk transfer, single and multiple transactions and interactive traffic, amongst others. The paper includes a description of the methodology, a visualisation of the attribute statistics that aids in recognising cluster types and a discussion of the stability and effectiveness of the methodology.

year: 2004

title: A critical analysis of the place of culture in evaluation

authors: Masters-Awatere, Bridgette

abstract: For the past 100 or so years formal evaluation has taken its lead from frameworks that originate from a culturally blind standpoint. Worldwide the major influence on evaluation practice comes from the United States of America. The absence of non-dominant (or indigenous) culturally constructed frameworks has been replicated around the world. Before the formation of the Aotearoa New Zealand Evaluation Association (ANZEA), as a New Zealand specific evaluation group, practitioners generally belonged to the Australasian Evaluation Society (AES) and joined in the sharing, adoption and adaptation of USAs Program Evaluation Standards. However, the context of evaluation in New Zealand has been somewhat different from the rest of the world, becoming more culturally centered than other countries. The role and place of the Treaty of Waitangi has been acknowledged as an attributing factor (ANZEA, 2011). Four indigenous “By Maori for Maori” health & wellbeing programmes externally evaluated were case studies within my research. I draw upon examples from the cases studies to highlight the vulnerable and contentious position indigenous service providers and indigenous evaluators were in. Adapting Sandra Grande’s (2004) analysis, I critiqued the context of the case study evaluations that commissioners considered as Kaupapa Maori. In this presentation I argue that while stakeholders perceived the work to be an indigenous evaluation, the case studies demonstrate that whitestream evaluation was prevalent.

text: A critical analysis of the place of culture in evaluation For the past 100 or so years formal evaluation has taken its lead from frameworks that originate from a culturally blind standpoint. Worldwide the major influence on evaluation practice comes from the United States of America. The absence of non-dominant (or indigenous) culturally constructed frameworks has been replicated around the world. Before the formation of the Aotearoa New Zealand Evaluation Association (ANZEA), as a New Zealand specific evaluation group, practitioners generally belonged to the Australasian Evaluation Society (AES) and joined in the sharing, adoption and adaptation of USAs Program Evaluation Standards. However, the context of evaluation in New Zealand has been somewhat different from the rest of the world, becoming more culturally centered than other countries. The role and place of the Treaty of Waitangi has been acknowledged as an attributing factor (ANZEA, 2011). Four indigenous “By Maori for Maori” health & wellbeing programmes externally evaluated were case studies within my research. I draw upon examples from the cases studies to highlight the vulnerable and contentious position indigenous service providers and indigenous evaluators were in. Adapting Sandra Grande’s (2004) analysis, I critiqued the context of the case study evaluations that commissioners considered as Kaupapa Maori. In this presentation I argue that while stakeholders perceived the work to be an indigenous evaluation, the case studies demonstrate that whitestream evaluation was prevalent.

year: 2015