title: Curing kinetics and effects of fibre surface treatment and curing parameters on the interfacial and tensile properties of hemp/epoxy composites

authors: Islam, Mohammad Saiful

subjects: hemp fibre

abstract: The curing kinetics of neat epoxy (NE) and hemp fibre/epoxy composites was studied and assessed using two dynamic models (the Kissinger and Flynn-Wall-Ozawa Models) and an isothermal model (the Autocatalytic Model) which was generally supported by the experimental data obtained from dynamic and isothermal differential scanning calorimetry (DSC) scans. The activation energies for the curing of composites exhibited lower values compared to curing of NE which is believed to be due to higher nucleophilic activity of the amine groups of the curing agent in the presence of fibres. The highest tensile strength, σ was obtained with composites produced with an epoxy to curing agent ratio of 1:1 and the highest Young's modulus, E was obtained with an epoxy to curing agent ratio of 1:1.2. Alkali treated hemp fibre/epoxy (ATFE) composites were found to have higher σ and E values compared to those for untreated hemp fibre/epoxy (UTFE) composites which was consistent with the trend for interfacial shear strength (IFSS) values. Composites σ and E were found to be higher for a processing temperature of 70°C than for 25°C for both UTFE and ATFE composites, but were found to decrease as the curing temperature was increased further to 120°C.

text: Curing kinetics and effects of fibre surface treatment and curing parameters on the interfacial and tensile properties of hemp/epoxy composites The curing kinetics of neat epoxy (NE) and hemp fibre/epoxy composites was studied and assessed using two dynamic models (the Kissinger and Flynn-Wall-Ozawa Models) and an isothermal model (the Autocatalytic Model) which was generally supported by the experimental data obtained from dynamic and isothermal differential scanning calorimetry (DSC) scans. The activation energies for the curing of composites exhibited lower values compared to curing of NE which is believed to be due to higher nucleophilic activity of the amine groups of the curing agent in the presence of fibres. The highest tensile strength, σ was obtained with composites produced with an epoxy to curing agent ratio of 1:1 and the highest Young's modulus, E was obtained with an epoxy to curing agent ratio of 1:1.2. Alkali treated hemp fibre/epoxy (ATFE) composites were found to have higher σ and E values compared to those for untreated hemp fibre/epoxy (UTFE) composites which was consistent with the trend for interfacial shear strength (IFSS) values. Composites σ and E were found to be higher for a processing temperature of 70°C than for 25°C for both UTFE and ATFE composites, but were found to decrease as the curing temperature was increased further to 120°C.

year: 2009

title: Psychosocial pathways to inconsistent condom use among male sex workers: personality, drug misuse and criminality

authors: Cortez, Fernanda C. Prado

subjects: Brazil

abstract: Background: This research compared street male sex workers in Santo André, Brazil, that reported consistent condom use with those that revealed inconsistent condom use with their clients, concerning personality aspects, impulsiveness, alcohol and drug consumption, depressive symptoms, sociodemographic data and criminal involvement. Methods: Eighty-six male sex workers were evaluated in face-to-face interviews at their place of work. A ‘snowball’ sampling procedure was used to access this hard-to-reach population. Findings: Male sex workers with inconsistent condom use showed greater involvement with criminal activities, higher reward dependence level and more frequent self-report of being HIV-positive. Conclusions: Conceptualisation of male sex workers’ psychological characteristics may be required where HIV risk is not only attributed to sex work per se, but to other aspects such as personality-related factors and negative identity.

text: Psychosocial pathways to inconsistent condom use among male sex workers: personality, drug misuse and criminality Background: This research compared street male sex workers in Santo André, Brazil, that reported consistent condom use with those that revealed inconsistent condom use with their clients, concerning personality aspects, impulsiveness, alcohol and drug consumption, depressive symptoms, sociodemographic data and criminal involvement. Methods: Eighty-six male sex workers were evaluated in face-to-face interviews at their place of work. A ‘snowball’ sampling procedure was used to access this hard-to-reach population. Findings: Male sex workers with inconsistent condom use showed greater involvement with criminal activities, higher reward dependence level and more frequent self-report of being HIV-positive. Conclusions: Conceptualisation of male sex workers’ psychological characteristics may be required where HIV risk is not only attributed to sex work per se, but to other aspects such as personality-related factors and negative identity.

year: 2011

title: Ngā kanohi hou – identifying and exploring the issues: Experiences of an intern

authors: Masters-Awatere, Bridgette

subjects: Maori

abstract: The current paper reflects upon the discovery of an intern from the post graduate diploma in community psychology programme (PGDipPsych (Com). The PGDipPsych (Com) is currently facilitated through the University of Waikato School of Arts and Social Sciences, Psychology Department. This journey of discovery is presented from the perspective of a Māori student who is employed in a mainstream public health organisation. The perspective of a person who is new to the workforce, and the “real world,” who views the surrounding environment with a pair of fresh eyes.

This paper highlights the importance of the internship period as it supports the student who moves from a structured environment with a strong emphasis on theory, towards a competitive, semi structured environment that is driven by deadlines, budgets and contracts.

Factors identified are the demands of Māori communities on Māori health researchers, supportive versus competitive environments, the benefits and drawbacks of being based in a mainstream health organisation, and the future direction of Māori health research. It is hoped that the current paper will encourage further discussion about the future direction of a diploma programme such as the PGDipPsychCom for Māori graduates of a New Zealand tertiary institution.

text: Ngā kanohi hou – identifying and exploring the issues: Experiences of an intern The current paper reflects upon the discovery of an intern from the post graduate diploma in community psychology programme (PGDipPsych (Com). The PGDipPsych (Com) is currently facilitated through the University of Waikato School of Arts and Social Sciences, Psychology Department. This journey of discovery is presented from the perspective of a Māori student who is employed in a mainstream public health organisation. The perspective of a person who is new to the workforce, and the “real world,” who views the surrounding environment with a pair of fresh eyes.

This paper highlights the importance of the internship period as it supports the student who moves from a structured environment with a strong emphasis on theory, towards a competitive, semi structured environment that is driven by deadlines, budgets and contracts.

Factors identified are the demands of Māori communities on Māori health researchers, supportive versus competitive environments, the benefits and drawbacks of being based in a mainstream health organisation, and the future direction of Māori health research. It is hoped that the current paper will encourage further discussion about the future direction of a diploma programme such as the PGDipPsychCom for Māori graduates of a New Zealand tertiary institution.

year: 1999