title: Modelling heat transfer during chilling and freezing of packaged foods in industrial refrigeration facilities

authors: Hoang, Duy

subjects: Modelling

abstract: Industrial refrigeration equipment companies are continuously looking for ways to optimise the design of chilling and freezing tunnels in order to minimise food quality loss and increase the energy efficiency of the equipment. However, possibilities for dedicated experimental tests of the industrial operations are limited due to a large amount of food product involved while the number of design variables to be considered is high. A cost-effective alternative to experiments is numerical modelling. The main goal of this research was to simulate heat transfer of packaged food products in a chilling and freezing tunnel. Computational fluid dynamics (CFD) models were developed to improve prediction in industrial cheese chilling and chicken freezing. The industrial cheese chilling model was developed based on six blocks of agar that mimic the product arrangement and airflow pattern of a cheese chiller; while the chicken freezing model represents the first case of a CFD freezing model where the geometry was derived empirically via computed tomography scan data. The model predictions were validated by experimental temperature histories generated as part of the study. Once validated, the model was used to investigate the cooling heterogeneity and the effect of different operating conditions on the processing time. In addition to the CFD model, a simple heat transfer simulation based on the one-dimensional finite difference method was developed for industrial users. Thermal property models in the literature were also reviewed to propose the most suitable choice for thermal processing calculations.

text: Modelling heat transfer during chilling and freezing of packaged foods in industrial refrigeration facilities Industrial refrigeration equipment companies are continuously looking for ways to optimise the design of chilling and freezing tunnels in order to minimise food quality loss and increase the energy efficiency of the equipment. However, possibilities for dedicated experimental tests of the industrial operations are limited due to a large amount of food product involved while the number of design variables to be considered is high. A cost-effective alternative to experiments is numerical modelling. The main goal of this research was to simulate heat transfer of packaged food products in a chilling and freezing tunnel. Computational fluid dynamics (CFD) models were developed to improve prediction in industrial cheese chilling and chicken freezing. The industrial cheese chilling model was developed based on six blocks of agar that mimic the product arrangement and airflow pattern of a cheese chiller; while the chicken freezing model represents the first case of a CFD freezing model where the geometry was derived empirically via computed tomography scan data. The model predictions were validated by experimental temperature histories generated as part of the study. Once validated, the model was used to investigate the cooling heterogeneity and the effect of different operating conditions on the processing time. In addition to the CFD model, a simple heat transfer simulation based on the one-dimensional finite difference method was developed for industrial users. Thermal property models in the literature were also reviewed to propose the most suitable choice for thermal processing calculations.

year: 2020

title: Work distribution of multiple Cartesian robot arms for kiwifruit harvesting

authors: Barnett, Josh

subjects: Science & Technology

abstract: Employing multiple robot arms for kiwifruit harvesting can raise the efficiency since the task completion time is shortened. However, task partitioning and reachability are two major concerns. It is found that the task completion time is minimized if task partitions for robot arms are uniform. However, the partition uniformity is influenced by the fruit indivisibility and fruit cluster growing style. It is also constrained by the fruit distribution across the canopy and the robot arm positions which affect the fruit reachability. This article investigates how to partition the tasks of kiwifruit harvesting so that the harvesting can be completed by multiple robot arms in the minimum time with an assumption that the fruits can be harvested by any robot arm. A parameter termed work distribution is introduced to measure how the task partitioning is different from the optimum. A research platform with two robot arms is implemented to show how to approximate the assumption. Ten field experiments of kiwifruit harvesting had been run by the research platform in two kiwifruit orchards in New Zealand with satisfactory outcomes.

text: Work distribution of multiple Cartesian robot arms for kiwifruit harvesting Employing multiple robot arms for kiwifruit harvesting can raise the efficiency since the task completion time is shortened. However, task partitioning and reachability are two major concerns. It is found that the task completion time is minimized if task partitions for robot arms are uniform. However, the partition uniformity is influenced by the fruit indivisibility and fruit cluster growing style. It is also constrained by the fruit distribution across the canopy and the robot arm positions which affect the fruit reachability. This article investigates how to partition the tasks of kiwifruit harvesting so that the harvesting can be completed by multiple robot arms in the minimum time with an assumption that the fruits can be harvested by any robot arm. A parameter termed work distribution is introduced to measure how the task partitioning is different from the optimum. A research platform with two robot arms is implemented to show how to approximate the assumption. Ten field experiments of kiwifruit harvesting had been run by the research platform in two kiwifruit orchards in New Zealand with satisfactory outcomes.

year: 2020-02-01

title: Strategic framing: indigenous culture, identity, and politics

authors: Schoenberger-Orgad, Michèle Anne

subjects: New Zealand

abstract: This article analyses the role played by culture and the strategic communication of culture in the formation and establishment of the Māori Party. As an indigenous grassroots party, which achieved electoral success in the 2005, general election in New Zealand, the Māori Party offers an unusual case of cultural primacy as a political party for indigenous people. The Māori Party campaigned to be the first successful party to give a distinctive voice to Māori in a parliament dominated by Pakeha (New Zealand Europeans).

In examining the Māori Party's formation and campaign as a case study, the article focuses on socio-political conditions, issues of national identity, media changes, and the cultural relations between Māori and Pakeha. It pays particular attention to those that influenced public opinion during the 14 months of election campaigning. It argues that the strategic framing of the Māori Party as a movement giving a distinctive voice for Māori established the foundations for the campaign's success. In conclusion, the significance of the achievements of the Māori Party in the 2008 general election are discussed as evidence of the now distinct and recognized representation of Māori within the New Zealand democratic process.

text: Strategic framing: indigenous culture, identity, and politics This article analyses the role played by culture and the strategic communication of culture in the formation and establishment of the Māori Party. As an indigenous grassroots party, which achieved electoral success in the 2005, general election in New Zealand, the Māori Party offers an unusual case of cultural primacy as a political party for indigenous people. The Māori Party campaigned to be the first successful party to give a distinctive voice to Māori in a parliament dominated by Pakeha (New Zealand Europeans).

In examining the Māori Party's formation and campaign as a case study, the article focuses on socio-political conditions, issues of national identity, media changes, and the cultural relations between Māori and Pakeha. It pays particular attention to those that influenced public opinion during the 14 months of election campaigning. It argues that the strategic framing of the Māori Party as a movement giving a distinctive voice for Māori established the foundations for the campaign's success. In conclusion, the significance of the achievements of the Māori Party in the 2008 general election are discussed as evidence of the now distinct and recognized representation of Māori within the New Zealand democratic process.

year: 2011