title: A simple experiment to determine the activation energy of the viscous flow of polymer solutions using a glass capillary viscometer

authors: Rohindra, D.R.

abstract: A simple viscometry experiment undertaken by an undergraduate polymer class as a research project is described. Viscosity is a measure of a fluid's resistance to flow and is affected by several factors, such as concentration and temperature. In this experiment, the viscosities of polyvinylpyrrolidone solutions (a polymeric material) of different concentrations were prepared in water and measured at various temperatures. The solution viscosity was found to increase gradually with increasing concentration up to similar to 5 mass%, with a dramatic increase after this. The calculated viscosity of water at different temperatures was comparable to reported values. The activation energy of viscous flow (E-a) of the different solutions was calculated and followed a similar trend as that for the viscosities of solutions of various concentrations. This experiment allowed students to better understand and explain the behaviour of macromolecules with respect to changing concentration and temperature. Furthermore, students correlated the viscosity and E-a results to understand how an increase in the concentration of a polymer solution resulted in increased entanglement of the polymer chains, consequently leading to an increase in viscosity and an increase in the activation energy of viscous flow. This experiment is safe, low cost, simple and requires only readily available apparatus.

text: A simple experiment to determine the activation energy of the viscous flow of polymer solutions using a glass capillary viscometer A simple viscometry experiment undertaken by an undergraduate polymer class as a research project is described. Viscosity is a measure of a fluid's resistance to flow and is affected by several factors, such as concentration and temperature. In this experiment, the viscosities of polyvinylpyrrolidone solutions (a polymeric material) of different concentrations were prepared in water and measured at various temperatures. The solution viscosity was found to increase gradually with increasing concentration up to similar to 5 mass%, with a dramatic increase after this. The calculated viscosity of water at different temperatures was comparable to reported values. The activation energy of viscous flow (E-a) of the different solutions was calculated and followed a similar trend as that for the viscosities of solutions of various concentrations. This experiment allowed students to better understand and explain the behaviour of macromolecules with respect to changing concentration and temperature. Furthermore, students correlated the viscosity and E-a results to understand how an increase in the concentration of a polymer solution resulted in increased entanglement of the polymer chains, consequently leading to an increase in viscosity and an increase in the activation energy of viscous flow. This experiment is safe, low cost, simple and requires only readily available apparatus.

year: 2012

title: Nuclear power in New Zealand: Attitudes and prospects

authors: Smith, Ron C.

subjects: nuclear

abstract: Traditional New Zealand attitudes with regard to all things nuclear are subjected to critical scrutiny.  It is argued that these may frequently lead us to take policy positions that do not best serve our national interests.  In the context of continuing anxiety about future energy supplies, an unreflective refusal to even consider civilian nuclear power is an outstanding example of this.  The chapter author makes a ‘modest proposal’.

text: Nuclear power in New Zealand: Attitudes and prospects Traditional New Zealand attitudes with regard to all things nuclear are subjected to critical scrutiny.  It is argued that these may frequently lead us to take policy positions that do not best serve our national interests.  In the context of continuing anxiety about future energy supplies, an unreflective refusal to even consider civilian nuclear power is an outstanding example of this.  The chapter author makes a ‘modest proposal’.

year: 2008

title: The Determinants of Tribal Population Growth in the New Zealand Census

authors: Rarere, Moana

subjects: tribal population growth

abstract: By the early twentieth century the notion that ethnic populations would dissipate was a commonly held belief.  However, after World War II, the modern world has seen an incredible resurgence in ethnic identities.  Ethnic conflicts, mobilisations, and the political movements of the 1950s and 1960s served as a major catalyst in the diffusion of indigenous identities and rights.  Consequently, indigenous groups in settler states, especially in North America, experienced population growth beyond the levels of natural demographic factors, that is, fertility, mortality and migration.  Researchers attributed a significant proportion of this growth to changing patterns of ethnic identification, also referred to as ethnic mobility .  Although this phenomenon is well documented in North America, it is only just beginning to be understood in relation to the New Zealand context. 

During the 1970s and 1980s, the indigenous Māori population of New Zealand gained substantial progress in political, social and economic spheres, following the same patterns of ethnic identity growth as in North America.  Despite these gains, the average individual socio-economic outcomes for Māori remain poor, especially in comparison to New Zealand Europeans/Pākehā.  Through key legislation, iwi (tribal) organisations became the core mechanism in which to address Māori socio-economic issues, achieve Māori aspirations and to manage Treaty of Waitangi settlement monies.  Subsequently, the need for iwi statistics for policy and planning purposes saw the reinstatement of iwi data in the New Zealand census in 1991.  Surprisingly, however, very little attention has been given to contemporary patterns of iwi demography.

Since the 1991 census, observations of total iwi population growth patterns indicate these patterns cannot solely be explained by natural demographic factors.  Furthermore, the growth trajectories of individual iwi were markedly different, and in some cases erratic.  These initial observations have raised the following key research questions: What do patterns of iwi growth look like?  What is the role of ethnic mobility?  What factors drive ethnic mobility?  Who changes iwi identification?  Why should we care?  

This thesis examines patterns of iwi identification in the New Zealand Census of Population and Dwellings from 1991 to 2006.  It uses statistical methods to not only document iwi population changes but to also identify the key determinants driving these trajectories.  In addition, this thesis considers ethnic mobility as an important driver of population growth but, situates this within the broader macro-political environment.  Along with the analysis of aggregate iwi population changes, this thesis also provides an in-depth analysis of four iwi groups – Ngāi Tahu, Waikato, Ngāti Awa and Tūhoe, in order to observe individual iwi dynamics that are not clearly visible at the aggregate level.

The findings of this thesis raise important implications for theories of ethnicity and the demographic study of ethnic populations.  For example, this thesis argues that the category of ethnic mobility is mainly contextual, that is, decisions to change ethnic responses are influenced by the broader political, social and economic contexts.  Furthermore this thesis contends that individual ethnic identification decisions are for the most part defined by ethnic categories imposed by the State.  While traditional views suggest ethnicity is fixed, intrinsic and kinship based, this thesis finds significant support for contemporary views that argue ethnicity is fluid, extrinsic and socially constructed.  Rather than reject traditional views of Maori identity, this study recognises that ethnic identities are complex, and that shifts in iwi identification is about connecting and reconnecting with whakapapa.  Thus this thesis argues that in order to understand individual iwi dynamics both points of view need to be considered.

text: The Determinants of Tribal Population Growth in the New Zealand Census By the early twentieth century the notion that ethnic populations would dissipate was a commonly held belief.  However, after World War II, the modern world has seen an incredible resurgence in ethnic identities.  Ethnic conflicts, mobilisations, and the political movements of the 1950s and 1960s served as a major catalyst in the diffusion of indigenous identities and rights.  Consequently, indigenous groups in settler states, especially in North America, experienced population growth beyond the levels of natural demographic factors, that is, fertility, mortality and migration.  Researchers attributed a significant proportion of this growth to changing patterns of ethnic identification, also referred to as ethnic mobility .  Although this phenomenon is well documented in North America, it is only just beginning to be understood in relation to the New Zealand context. 

During the 1970s and 1980s, the indigenous Māori population of New Zealand gained substantial progress in political, social and economic spheres, following the same patterns of ethnic identity growth as in North America.  Despite these gains, the average individual socio-economic outcomes for Māori remain poor, especially in comparison to New Zealand Europeans/Pākehā.  Through key legislation, iwi (tribal) organisations became the core mechanism in which to address Māori socio-economic issues, achieve Māori aspirations and to manage Treaty of Waitangi settlement monies.  Subsequently, the need for iwi statistics for policy and planning purposes saw the reinstatement of iwi data in the New Zealand census in 1991.  Surprisingly, however, very little attention has been given to contemporary patterns of iwi demography.

Since the 1991 census, observations of total iwi population growth patterns indicate these patterns cannot solely be explained by natural demographic factors.  Furthermore, the growth trajectories of individual iwi were markedly different, and in some cases erratic.  These initial observations have raised the following key research questions: What do patterns of iwi growth look like?  What is the role of ethnic mobility?  What factors drive ethnic mobility?  Who changes iwi identification?  Why should we care?  

This thesis examines patterns of iwi identification in the New Zealand Census of Population and Dwellings from 1991 to 2006.  It uses statistical methods to not only document iwi population changes but to also identify the key determinants driving these trajectories.  In addition, this thesis considers ethnic mobility as an important driver of population growth but, situates this within the broader macro-political environment.  Along with the analysis of aggregate iwi population changes, this thesis also provides an in-depth analysis of four iwi groups – Ngāi Tahu, Waikato, Ngāti Awa and Tūhoe, in order to observe individual iwi dynamics that are not clearly visible at the aggregate level.

The findings of this thesis raise important implications for theories of ethnicity and the demographic study of ethnic populations.  For example, this thesis argues that the category of ethnic mobility is mainly contextual, that is, decisions to change ethnic responses are influenced by the broader political, social and economic contexts.  Furthermore this thesis contends that individual ethnic identification decisions are for the most part defined by ethnic categories imposed by the State.  While traditional views suggest ethnicity is fixed, intrinsic and kinship based, this thesis finds significant support for contemporary views that argue ethnicity is fluid, extrinsic and socially constructed.  Rather than reject traditional views of Maori identity, this study recognises that ethnic identities are complex, and that shifts in iwi identification is about connecting and reconnecting with whakapapa.  Thus this thesis argues that in order to understand individual iwi dynamics both points of view need to be considered.

year: 2012