The management of heavy construction equipment is a difficult task. Equipment managers are often called upon to make complex economic decisions involving the machines in their charge. These decisions include those concerning acquisitions, maintenance, repairs, rebuilds, replacements, and retirements. The equipment manager must also be able to forecast internal rental rates for their machinery. Repair and maintenance expenditures can have significant impacts on these economic decisions and forecasts. The purpose of this research was to identify a regression model that can adequately represent repair costs in terms of machine age in cumulative hours of use. The study was conducted using field data on 270 heavy construction machines from four different companies. Nineteen different linear and transformed non-linear models were evaluated. A second-order polynomial expression was selected as the best. It was demonstrated how this expression could be incorporated in the Cumulative Cost Model developed by Vorster where it can be used to identify optimum economic decisions. It was also demonstrated how equipment managers could form their own regression equations using standard spreadsheet and database software. / Ph. D.

Major changes that emphasise the importance of a balanced work and family life have occurred within organisations. Inability to manage this integration between the work and home domains can affect the performance of organisations and the wellbeing of their employees. In order to measure work-home interaction and wellbeing, it is important to use valid, equivalent and reliable instruments. However, there is a lack of empirical research when investigating work-home interaction, burnout and work engagement in the earthmoving equipment industry in South Africa. Furthermore, the earthmoving equipment industry is a multicultural environment and construct equivalence across subgroups therefore becomes important when measuring work-home interaction, burnout and work engagement across different cultural or language groups. It also seems relevant to consider differences in the work-home interaction and work wellness levels between important demographic groups in the earthmoving equipment industry. It appears as if burnout and engagement can be seen as part of the total wellness continuum; and that job characteristics may be related to burnout and engagement through negative and positive work-home interaction. However, little information was found that included these factors in a structural model for the earthmoving equipment industry. The objectives of this research were to test the psychometric properties of the Survey Work- Home Interaction - Nijmegen (SWING), the Maslach Burnout Inventory - General Survey (MBI-GS) and the Utrecht Work Engagement Scale (UWES); to determine if various demographic groups differ with regard to work-home interaction and wellbeing; and to test a structural model that includes job characteristics, work-home interaction and wellbeing for employees in the earthmoving industry. A cross-sectional survey design was used. Random samples (n = 528) were taken from employees in the earthmoving equipment industry in Gauteng, the Limpopo Province, Mpumalanga, the Northern Cape, the Western Cape, the Eastern Cape, Kwa-Zulu Natal and the North West Province. Structural equation modelling confirmed a four-factor model of work-home interaction which measures negative work-home interference, positive work-home interference, negative homework interference and positive home-work interference. This factor structure was equivalent across language, ethnicity, gender, education, marital status and parental status. All four factors were reliable. The participants reported more negative WHI than negative HWI, and more positive HWI than positive WHI. It was found that statistically significant differences that are based on age, gender, language, ethnicity, a partner's contribution to household income and the different business units exist between the demographic groups. The results confirmed a four-factor structure of burnout (exhaustion, cognitive weariness, cynicism and professional efficacy) and a two-factor structure of work engagement (including vigour and dedication). These structures were equivalent across language and education groups, and all scales were reliable. SEM analyses supported a two-factor structure for the wellness construct, consisting of burnout (exhaustion, cognitive weariness and cynicism) and engagement (vigour, dedication and professional efficacy), which was equivalent for the language and education groups. Statistically significant differences that are based on age, gender, language and the different business units were found between the demographic groups. Structural equation modelling showed that job demands are associated with negative WHI and consequently with burnout, providing support for a full-mediation effect of negative WHI. Job resources were associated with negative WHI and consequently with burnout, providing support for partial mediation of negative WHI between job resources and burnout. Job resources were also associated with positive WHI and consequently with engagement, providing support for partial mediation of positive WHI between job resources and engagement. Recommendations for the organisation and future research were made. / Thesis (Ph.D. (Industrial Psychology))--North-West University, Potchefstroom Campus, 2007.

In an ever-changing world, people are constantly faced with the challenge of simultaneously managing multiple roles in their work as well as their home-sphere. It therefore becomes increasingly important to maintain a balance in these two life spheres. Unfortunately, a gap exists between the positive and negative side of work-home balance as most research focuses on the negative side. Recently, a much needed instrument was develop in the Netherlands, namely the Survey Work-Home Interaction - Nijmegen (SWING), which measures both the direction of influence (work→home and vice versa) and the quality of influence (negative vs. positive). The objectives of this study were to validate the Survey Work-Home Interaction - Nijmegen (SWING) for workers of the earthmoving equipment industry in a South African context, to determine its construct equivalence and bias for different language groups, and to determine differences regarding work-home interaction between different demographic groups. A cross-sectional survey design was used. Random samples (n = 330) were taken of workers in the earthmoving equipment industry across South Africa. The SWING and a biographical questionnaire were administered. Item bias analyses, exploratory factor analysis, Cronbach alpha coefficients, MANOVAs, ANOVAs and T-tests were used to analyse the data. Exploratory factor analysis showed that the SWING consists of four factors, namely Negative Work-Home Interference, Negative Home-Work Interference, Positive Work-Home Interference and Positive Home-Work Interference. All four factors showed acceptable internal consistencies. No evidence was found for uniform or non-uniform bias of the items of the SWING for different language groups. Exploratory factor analysis with target rotations confirmed the construct equivalence of the work-home interface construct. There were also no differences regarding work-home interaction between different demographic groups, except for a practically significant difference (medium effect) between males and females with respect to negative Work-Home Interaction levels. Recommendations were made for further research. / Thesis (M.Com. (Industrial Psychology))--North-West University, Potchefstroom Campus, 2005.

In an ever-changing world, people are constantly faced with the challenge of simultaneously managing multiple roles in their work as well as their home-sphere. It therefore becomes increasingly important to maintain a balance in these two life spheres. Unfortunately, a gap exists between the positive and negative side of work-home balance as most research focuses on the negative side. Recently, a much needed instrument was develop in the Netherlands, namely the Survey Work-Home Interaction - Nijmegen (SWING), which measures both the direction of influence (work→home and vice versa) and the quality of influence (negative vs. positive). The objectives of this study were to validate the Survey Work-Home Interaction - Nijmegen (SWING) for workers of the earthmoving equipment industry in a South African context, to determine its construct equivalence and bias for different language groups, and to determine differences regarding work-home interaction between different demographic groups. A cross-sectional survey design was used. Random samples (n = 330) were taken of workers in the earthmoving equipment industry across South Africa. The SWING and a biographical questionnaire were administered. Item bias analyses, exploratory factor analysis, Cronbach alpha coefficients, MANOVAs, ANOVAs and T-tests were used to analyse the data. Exploratory factor analysis showed that the SWING consists of four factors, namely Negative Work-Home Interference, Negative Home-Work Interference, Positive Work-Home Interference and Positive Home-Work Interference. All four factors showed acceptable internal consistencies. No evidence was found for uniform or non-uniform bias of the items of the SWING for different language groups. Exploratory factor analysis with target rotations confirmed the construct equivalence of the work-home interface construct. There were also no differences regarding work-home interaction between different demographic groups, except for a practically significant difference (medium effect) between males and females with respect to negative Work-Home Interaction levels. Recommendations were made for further research. / Thesis (M.Com. (Industrial Psychology))--North-West University, Potchefstroom Campus, 2005.

Major changes that emphasise the importance of a balanced work and family life have occurred within organisations. Inability to manage this integration between the work and home domains can affect the performance of organisations and the wellbeing of their employees. In order to measure work-home interaction and wellbeing, it is important to use valid, equivalent and reliable instruments. However, there is a lack of empirical research when investigating work-home interaction, burnout and work engagement in the earthmoving equipment industry in South Africa. Furthermore, the earthmoving equipment industry is a multicultural environment and construct equivalence across subgroups therefore becomes important when measuring work-home interaction, burnout and work engagement across different cultural or language groups. It also seems relevant to consider differences in the work-home interaction and work wellness levels between important demographic groups in the earthmoving equipment industry. It appears as if burnout and engagement can be seen as part of the total wellness continuum; and that job characteristics may be related to burnout and engagement through negative and positive work-home interaction. However, little information was found that included these factors in a structural model for the earthmoving equipment industry. The objectives of this research were to test the psychometric properties of the Survey Work- Home Interaction - Nijmegen (SWING), the Maslach Burnout Inventory - General Survey (MBI-GS) and the Utrecht Work Engagement Scale (UWES); to determine if various demographic groups differ with regard to work-home interaction and wellbeing; and to test a structural model that includes job characteristics, work-home interaction and wellbeing for employees in the earthmoving industry. A cross-sectional survey design was used. Random samples (n = 528) were taken from employees in the earthmoving equipment industry in Gauteng, the Limpopo Province, Mpumalanga, the Northern Cape, the Western Cape, the Eastern Cape, Kwa-Zulu Natal and the North West Province. Structural equation modelling confirmed a four-factor model of work-home interaction which measures negative work-home interference, positive work-home interference, negative homework interference and positive home-work interference. This factor structure was equivalent across language, ethnicity, gender, education, marital status and parental status. All four factors were reliable. The participants reported more negative WHI than negative HWI, and more positive HWI than positive WHI. It was found that statistically significant differences that are based on age, gender, language, ethnicity, a partner's contribution to household income and the different business units exist between the demographic groups. The results confirmed a four-factor structure of burnout (exhaustion, cognitive weariness, cynicism and professional efficacy) and a two-factor structure of work engagement (including vigour and dedication). These structures were equivalent across language and education groups, and all scales were reliable. SEM analyses supported a two-factor structure for the wellness construct, consisting of burnout (exhaustion, cognitive weariness and cynicism) and engagement (vigour, dedication and professional efficacy), which was equivalent for the language and education groups. Statistically significant differences that are based on age, gender, language and the different business units were found between the demographic groups. Structural equation modelling showed that job demands are associated with negative WHI and consequently with burnout, providing support for a full-mediation effect of negative WHI. Job resources were associated with negative WHI and consequently with burnout, providing support for partial mediation of negative WHI between job resources and burnout. Job resources were also associated with positive WHI and consequently with engagement, providing support for partial mediation of positive WHI between job resources and engagement. Recommendations for the organisation and future research were made. / Thesis (Ph.D. (Industrial Psychology))--North-West University, Potchefstroom Campus, 2007.

The objectives of this study were to validate the Maslach Burnout Inventory - General Survey (MBI-GS) and the Oldenburg Burnout Inventory (OLBI), to determine the construct equivalence and item bias of these instruments for employees in an earthmoving equipment industry in South &ca of different language groups, to determine the correlation between the MBI-GS and the OLBI, and to investigate the relationship between burnout and various demographic characteristics. A random sample of 326 employees in an earthmoving equipment industry of eight provinces in South Africa was taken. The MBI-GS, the OLBI and a biographical questionnaire were used as measuring instruments. Cronbach alpha coefficients, inter-item correlation coefficients, Pearson product-moment correlation coefficients and exploratory factor analysis were used to analyse the data The results showed that three factors of the MBI-GS and two factors of the OLBI exist for different language groups. Exploratory factor analysis with target rotations confirmed the construct equivalence of the three factors of the MBI-GS and the two factors for the OLBI for different language groups. No evidence was found for uniform or non-uniform bias of the items of the MBI-GS or the OLBI for different language groups. Results indicated that no differences with respect to levels of burnout exist between various demographic characteristics. Recommendations were made for further research. / Thesis (M.Com. (Industrial Psychology))--North-West University, Potchefstroom Campus, 2005.

The objectives of this study were to validate the Maslach Burnout Inventory - General Survey (MBI-GS) and the Oldenburg Burnout Inventory (OLBI), to determine the construct equivalence and item bias of these instruments for employees in an earthmoving equipment industry in South &ca of different language groups, to determine the correlation between the MBI-GS and the OLBI, and to investigate the relationship between burnout and various demographic characteristics. A random sample of 326 employees in an earthmoving equipment industry of eight provinces in South Africa was taken. The MBI-GS, the OLBI and a biographical questionnaire were used as measuring instruments. Cronbach alpha coefficients, inter-item correlation coefficients, Pearson product-moment correlation coefficients and exploratory factor analysis were used to analyse the data The results showed that three factors of the MBI-GS and two factors of the OLBI exist for different language groups. Exploratory factor analysis with target rotations confirmed the construct equivalence of the three factors of the MBI-GS and the two factors for the OLBI for different language groups. No evidence was found for uniform or non-uniform bias of the items of the MBI-GS or the OLBI for different language groups. Results indicated that no differences with respect to levels of burnout exist between various demographic characteristics. Recommendations were made for further research. / Thesis (M.Com. (Industrial Psychology))--North-West University, Potchefstroom Campus, 2005.