30 research outputs found

    Developing whole-life cost models for retrofit options in office buildings

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    Office retrofit building projects have become a subject of increased attention among building researchers in the United Kingdom, and in many economically advanced nations. Existing whole-life costing models have however, not proven to be robust enough to deal with these retrofit building scenarios. There is a growing body of evidence that conceptual modifications in the mechanics of whole-life cost modelling, could facilitate improvements in the long-term cost assessment of buildings. Recent research has made a case for the existence of revocability and disruption, in the appraisal of retrofit building investments. Revocability, connotes the potential for variability, in the future cost projections of a building over its estimated life. Disruption relates to the diminished building use, or unusability, over a period of implementing a retrofit initiative. Existing whole-life cost models have however, not recognised the implications of revocability and disruption in their framework. This study conducts an investigation into the whole-life costing of office retrofit building projects, and develops a Fuzzy New-Generation Whole-life Costing approach. Two office retrofit building projects are adopted, to appraise the identified issues in the whole-life costing framework. A number of building configuration permutations (BCPs) constituting different retrofit options, are developed in both projects. The potential implication of revocability and disruption, are evaluated based on probability and fuzzy logic principles respectively. Sensitivity analysis is applied to discount rate assumptions over the estimated lives, of the projects considered. The Spearman’s rank correlation coefficient is used in analysing the ranking results of selected projects. This provided an assessment of the relative preference of BCPs in the projects.Results from the case studies show 1) disruption issues account for up to 12% of initial capital costs; 2) revocability accounts for up to 35% of initial capital cost, over a 20-year life; up to 119%, over a 60-year life; 3) up to 2% underestimation in the whole-life cost, over a 20-year life; and up to 45% underestimation, over a 60-year period, in the SPACE project; 4) up to 9% underestimation in the whole-life cost, over a 20-year life; and up to 53% underestimation, over a 60-year life, in the MS project

    Developing whole-life cost models for retrofit options in office buildings

    Get PDF
    Office retrofit building projects have become a subject of increased attention among building researchers in the United Kingdom, and in many economically advanced nations. Existing whole-life costing models have however, not proven to be robust enough to deal with these retrofit building scenarios. There is a growing body of evidence that conceptual modifications in the mechanics of whole-life cost modelling, could facilitate improvements in the long-term cost assessment of buildings. Recent research has made a case for the existence of revocability and disruption, in the appraisal of retrofit building investments. Revocability, connotes the potential for variability, in the future cost projections of a building over its estimated life. Disruption relates to the diminished building use, or unusability, over a period of implementing a retrofit initiative. Existing whole-life cost models have however, not recognised the implications of revocability and disruption in their framework. This study conducts an investigation into the whole-life costing of office retrofit building projects, and develops a Fuzzy New-Generation Whole-life Costing approach. Two office retrofit building projects are adopted, to appraise the identified issues in the whole-life costing framework. A number of building configuration permutations (BCPs) constituting different retrofit options, are developed in both projects. The potential implication of revocability and disruption, are evaluated based on probability and fuzzy logic principles respectively. Sensitivity analysis is applied to discount rate assumptions over the estimated lives, of the projects considered. The Spearman’s rank correlation coefficient is used in analysing the ranking results of selected projects. This provided an assessment of the relative preference of BCPs in the projects.Results from the case studies show 1) disruption issues account for up to 12% of initial capital costs; 2) revocability accounts for up to 35% of initial capital cost, over a 20-year life; up to 119%, over a 60-year life; 3) up to 2% underestimation in the whole-life cost, over a 20-year life; and up to 45% underestimation, over a 60-year period, in the SPACE project; 4) up to 9% underestimation in the whole-life cost, over a 20-year life; and up to 53% underestimation, over a 60-year life, in the MS project

    Perception of farmers on agroforestry systems adoption in Akinyele Local Government Area, Ibadan, Oyo State, Nigeria

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    The study assessed farmers’ characteristic variables and perception towards the adoption of agroforestry practices in Akinyele Local Government, Ibadan, Oyo State. Multistage Sampling Technique was used for the study. Five Wards which include Ijaye /Ojedeji, Ajibade/Alabata/Elekuru,  Akinyele/Isabiyi/Irepodun, Ojo Emo/Moniya and Ojoo/Ajibode/Laniba were randomly selected from the Local Government Area. Ajeja, Alabata, Akinyele, Moniya and Idowu oko areas were selected from each of the Wards, respectively while ten (10) farmers were selected from each of these areas. Descriptive statistics such as frequency and percentage distributions as well as correlational studies were used to analyse the collected data. 34 % of the respondents were involved in the practice of agroforestry according to the study. The correlation (r value) at (p< 0.01) also shows that there is a significant association between respondents’ characteristic variables such as age, educational and marital status and adoption of agroforestry practices, while age, sex, marital and educational status are significant on agroforestry perception. It is recommended that awareness  on benefits of agroforestry should be raised in order to create needed awareness and its importance, adequate technical supports should be  provided for farmers interested in practicing agroforestry and also the efficient use of available farmlands of all types of landholders should be  ensured. Keywords: Farmers’ characteristic variables; Perception; Adoption; Agroforestry practices

    Life cycle option appraisal in retrofit buildings

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    © 2018 Elsevier B.V. Determining the economic benefits of building asset retrofitting has been a difficult task due to the paucity of reliable data and the inherent limitations of existing life-cycle costing models. For example, most life cycle costing models do not accommodate revocability (i.e. the economic impacts of reversing a decision previously made on a building configuration). Thus, the impact of revocability in the life cycle appraisal of a retrofit building project is assessed in this paper. Using a case-study approach, the economic impact of revocability is appraised using a real-options framework. The flexibility and non-flexibility of life cycle options are evaluated and compared. It is revealed that the cost of revocability may be as high as 27% in retrofit buildings. Flexible options have up to 50% chance of exceeding the performance of non-flexible retrofit options when fabric insulation measures and smart control installations are considered. The incorporation of renewable energy may undermine the performance of flexible options due to their inherent uncertainties in the cost and evolution in the future. There is, however, a need to develop holistic lifecycle option appraisal approaches for scenario feasiblility assessments to optimise the value of retrofit interventions in buildings

    Risk assessment in the maintenance of offshore caisson operations

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    Undertaking maintenance of offshore caissons is a pervasive challenge that involves an array of risks and uncertainties. Despite the adoption of standardised and routine maintenance procedures that are subject to on-going improvements, the rate of failure in offshore caissons remains relatively high. To manage the effect of risk and uncertainties associated with the maintenance of offshore caissons, expert judgment can be drawn upon to better understand and capture the issues that contribute to their failure. Using a case study of an offshore hydrocarbon discharge caisson in the North Sea of the United Kingdom, expert judgements from industry practitioners are obtained using the Delphi Interview and Analytic Hierarchy Process (AHP) technique to rank 14 possible recovery options. Sensitivity analysis is used to ascertain the suitability of each of the options. Results reveal that the Delphi technique employed provided a robust means to garner invaluable insights from experts about the issues associated with caisson failure. The corollary is the development of a framework that serves as a point of reference to identify and assess the risks in offshore caisson maintenance operations. This framework can also be used in conjunction with existing probabilistic methods to improve the effectiveness of decision-making during operations and maintenance

    An assessment of cross infection control practice in Nigerian oral health care workers

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    Objective: This study was aimed at assessing the cross infection control practices among dental health care practitioners in Nigeria.Method: Questionnaires were administered to 137 Dentists, 56 Dental Therapists and 62 Dental Surgery Assistants (DSAs) practicing in both government and private practices across the six geopolitical areas of the country. Each questionnaire comprised of questions on basic infection control procedures.Result: Results indicate that all the participants use gloves during treatment, 93.8% wear face mask, 48.5% wear eye protection, 95.5% clinical gown/coat. Furthermore 27.3% have had a puncture or laceration from a dental needle or instrument while only 41.4% have had Hepatitis B vaccination.Conclusion: Infection control practice by dental personnel in Nigeria has improved compared to previous studies, particularly in the use of gloves. However in the areas of sterilization, vaccination, there are needs for improvement.Key words: Infection Control, Dental Health Care Workers, Sterilization, Immunizatio

    Burnout and Work Engagement among US Dentists

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    Burnout and Work Engagement among US Dentists

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    © Wolters Kluwer Health, Inc. All rights reserved.Background Burnout is a threat to patient safety. It relates to emotional exhaustion, depersonalization, and lack of personal accomplishment. Work engagement conversely composed of levels of vigor, dedication, and absorption in one's profession. The aim of this study was to examine burnout and work engagement among US dentists. Methods This study used the extensively validated Maslach Burnout Inventory-Human Services Survey and Utrecht Work Engagement Scale to measure burnout in a self-administered survey of 167 US dentists who attended continuing education courses held in Boston, Pittsburg, Iowa City, and Las Vegas. The mean scores on the 3 subscales of Maslach Burnout Inventory-Human Services Survey and Utrecht Work Engagement Scale were computed. The interscale correlations between the components of burnout and work engagement were assessed using Pearson correlations. We used 1-way analysis of variance and independent 2 sample t tests to examine the relationship between burnout and work engagement across sex and various age categories. Prevalence of burnout in our study population was also computed. Results We observed that 13.2% of our study population experienced burnout and 16.2% of our study population was highly work engaged. There was a statistically significant, unadjusted association between burnout risk and work engagement (χ2 = 22.51, P < 0.0001). Furthermore, the scores in the subscales of burnout were significantly correlated with scores in the subscales of work engagement. Conclusions In this preliminary study, we observed some evidence of burnout among practicing US dentists. It is imperative that the dental profession understands this and works to promote professional practices that increase work engagement and decrease burnout

    Letter to the Editor: Authors’ response

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