99 resultados para Faria, Almeida, 1943-


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Highway infrastructure development typically requires major capital input. Unless planned properly, such requirements can cause serious financial constraints for investors. The push for sustainability adds a new dimension to the complexity of evaluating highway projects. Finding environmentally and socially responsible solutions for highway construction will improve its potential for acceptance by the society and in many instances the infrastructure's life span. Even so, the prediction and determination of a project's long-term financial viability can be a precarious exercise. Existing studies in this area have not indicated details of how to identify and deal with costs incurred in pursuing sustainability measures in highway infrastructure. This paper provides insights into the major challenges of implementing sustainability in highway project development in terms of financial concerns and obligations. It discusses the results from recent research through a literature study and a questionnaire survey of key industry stakeholders involved in highway infrastructure development. The research identified critical cost components relating to sustainability measures based on perspectives of industry stakeholders. All stakeholders believe sustainability related costs are an integral part of the decision making. However, the importance rating of these costs is relative to each stakeholder's core business objectives. This will influence the way these cost components are dealt with during the evaluation of highway investment alternatives and financial implications. This research encourages positive thinking among the highway infrastructure practitioners about sustainability. It calls for the construction industry to maximise sustainability deliverables while ensuring financial viability over the life cycle of highway infrastructure projects.

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Several chronic infections known to be associated with malignancy have established oncogenic properties. However the existence of chronic inflammatory conditions that do not have an established infective cause and are associated with the development of tumours strongly suggests that the inflammatory process itself provides the prerequisite environment for the development of malignancy. This environment includes upregulation of mediators of the inflammatory response such as cyclo-oxygenase (COX)-2 leading to the production of inflammatory cytokines and prostaglandins which themselves may suppress cell mediated immune responses and promote angiogenesis. These factors may also impact on cell growth and survival signalling pathways resulting in induction of cell proliferation and inhibition of apoptosis. Furthermore, chronic inflammation may lead to the production of reactive oxygen species and metabolites such as malondialdehyde within the affected cells that may in turn induce DNA damage and mutations and, as a result, be carcinogenic. Here it is proposed that the conditions provided by a chronic inflammatory environment are so essential for the progression of the neoplastic process that therapeutic intervention aimed at inhibiting inflammation, reducing angiogenesis and stimulating cell mediated immune responses may have a major role in reducing the incidence of common cancers. © 2001 Cancer Research Campaign http://www.bjcancer.com.

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Collaborative infrastructure projects use hybrid formal and informal governance structures to manage transactions. Based on previous desk-top research, the authors identified the key mechanisms underlying project governance, and posited the performance implications of the governance (Chen et al. 2012). The current paper extends that qualitative research by testing the veracity of those findings using data from 320 Australian construction organisations. The results provide, for the first time, reliable and valid scales to measure governance and performance of collaborative projects, and the relationship between them. The results confirm seven of seven hypothesised governance mechanisms; 30 of 43 hypothesised underlying actions; eight of eight hypothesised key performance indicators; and the dual importance of formal and informal governance. A startling finding of the study was that the implementation intensity of informal mechanisms (non-contractual conditions) is a greater predictor of project performance variance than that of formal mechanisms (contractual conditions). Further, contractual conditions do not directly impact project performance; instead their impact is mediated by the non-contractual features of a project. Obligations established under the contract are not sufficient to optimise project performance.

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Participation in sufficient levels of physical activity provides significant health benefits, particularly in older adults. The monitoring of physical activity levels in the Western Australian population is therefore necessary for developing and implementing strategies and programs for increasing participation. The Premier’s Physical Activity Taskforce (PATF) conducted a survey in 2006 to measure physical activity levels among Western Australian adults to follow-up the 1999 and 2002 state physical activity surveys. There is now widespread agreement that many health problems of older life – including the onset of frailty and disability – can be postponed or delayed by adopting health-enhancing habits such as physical activity. Adults over 65 years are the most rapidly growing age group and will continue to rise as more persons turn 65. If older adults could be encouraged to be more active as they age, frailty and disability associated with falls would be reduced, and function and physical and mental health in older people would be improved thereby reducing the burden of disease and injury. Given that physical inactivity is one of the most important and modifiable risk factors contributing to ill health, particularly for people as they age, the overall aim of this study was to examine patterns of physical activity in those aged 45 years and over – referred to hereafter as baby boomers+ – in more detail.

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This paper uses finite element techniques to investigate the performance of buried tunnels subjected to surface blasts incorporating fully coupled Fluid Structure Interaction and appropriate material models which simulate strain rate effects. Modelling techniques are first validated against existing experimental results and then used to treat the blast induced shock wave propagation and tunnel response in dry and saturated sands. Results show that the tunnel buried in saturated sand responds earlier than that in dry sand. Tunnel deformations decrease with distance from explosive in both sands, as expected. In the vicinity of the explosive, the tunnel buried in saturated sand suffered permanent deformation in both axial and circumferential directions, whereas the tunnel buried in dry sand recovered from most of the axial deformation. Overall, response of the tunnel in saturated sand is more severe for a given blast event and shows the detrimental effect of pore water on the blast response of buried tunnels. The validated modelling techniques developed in this paper can be used to investigate the blast response of tunnels buried in dry and saturated sands.

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It has become more and more demanding to investigate the impacts of wind farms on power system operation as ever-increasing penetration levels of wind power have the potential to bring about a series of dynamic stability problems for power systems. This paper undertakes such an investigation through investigating the small signal and transient stabilities of power systems that are separately integrated with three types of wind turbine generators (WTGs), namely the squirrel cage induction generator (SCIG), the doubly fed induction generator (DFIG), and the permanent magnet generator (PMG). To examine the effects of these WTGs on a power system with regard to its stability under different operating conditions, a selected synchronous generator (SG) of the well-known Western Electricity Coordinating Council (WECC three-unit nine-bus system and an eight-unit 24-bus system is replaced in turn by each type of WTG with the same capacity. The performances of the power system in response to the disturbances are then systematically compared. Specifically, the following comparisons are undertaken: (1) performances of the power system before and after the integration of the WTGs; and (2) performances of the power system and the associated consequences when the SCIG, DFIG, or PMG are separately connected to the system. These stability case studies utilize both eigenvalue analysis and dynamic time-domain simulation methods.

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Numerous research studies have evaluated whether distance learning is a viable alternative to traditional learning methods. These studies have generally made use of cross-sectional surveys for collecting data, comparing distance to traditional learners with intent to validate the former as a viable educational tool. Inherent fundamental differences between traditional and distance learning pedagogies, however, reduce the reliability of these comparative studies and constrain the validity of analyses resulting from this analytical approach. This article presents the results of a research project undertaken to analyze expectations and experiences of distance learners with their degree programs. Students were given surveys designed to examine factors expected to affect their overall value assessment of their distance learning program. Multivariate statistical analyses were used to analyze the correlations among variables of interest to support hypothesized relationships among them. Focusing on distance learners overcomes some of the limitations with assessments that compare off- and on-campus student experiences. Evaluation and modeling of distance learner responses on perceived value for money of the distance education they received indicate that the two most important influences are course communication requirements, which had a negative effect, and course logistical simplicity, which revealed a positive effect. Combined, these two factors accounted for approximately 47% of the variability in perceived value for money of the educational program of sampled students. A detailed focus on comparing expectations with outcomes of distance learners complements the existing literature dominated by comparative studies of distance and nondistance learners.

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The construction industry has long been burdened with inherent adversarial relationships among the parties and the resulting disputes. Dispute review boards (DRBs) have emerged as alternatives to settle construction-related disputes outside courts. Although DRBs have found support in some quarters of the construction industry, the quantitative assessment of the impact of DRBs has not been adequately addressed. This paper presents the results of a research project undertaken to assess the impact of DRBs on the construction program of a large-scale highway agency. Three dimensions of DRB impact were assessed: (1) influence on project cost and schedule performance, (2) effectiveness of DRBs in preventing and resolving construction disputes, and (3) costs of DRB implementation. The analyses encompass data from approximately 3,000 projects extending over a 10-year period (2000–2009). Quantitative measures of performance were developed and analyzed for each category. Projects that used DRBs faced reduced costs and schedule growth (6.88 and 12.92%, respectively) when compared to non-DRB projects (11.53 and 28.96%). DRBs were also found to be effective in avoiding and settling disputes; the number of arbitration cases reduced consistently after DRB implementation, and DRBs have a success rate of 97% in settling disputes for which DRBs were used. Moreover, costs of DRBs were found to comprise a relatively small fraction (i.e., approximately 0.3%) of total project budgets. It was concluded that DRBs were effective dispute prevention and resolution alternatives with no significant adverse effects on project performance.

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A total of 1,625 tornadoes occurred in the United States in 2011, resulting in economic losses that exceeded $25 billion. Two tornado outbreaks stand out because they caused more than half of those losses. The tornadoes that cut through Tuscaloosa, Alabama, on April 27 and Joplin, Missouri, on May 22 were responsible for a combined 223 fatalities and more than 13,000 damaged buildings in the two cities. Although the economic losses associated with tornado damage are well documented, the writers argue that the overall impact should encompass longer term, broader considerations such as the social disruption and psychological effects that impact communities. This paper examines observations by tornado damage assessment teams led by the first author in these two medium-sized cities and suggests that the evolution of building codes and past approaches to construction have led to conditions that made this extent of damage possible. The authors outline a multidisciplinary path forward that incorporates engineering research and social and economic studies into a new design paradigm leading to building code changes and social practices that will improve resistance and mitigate future losses at a community level from tornadoes.

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Repair, maintenance, minor alteration, and addition work (RMAA) has become more and more important in developed societies, but its safety performance is alarming. For example, RMAA projects accounted for 53.2% of the total construction market and the percentage of RMAA accidents to all construction accidents in the Hong Kong Special Administrative Region (HKSAR) increased considerably in 2007. The RMAA sector has a huge potential for safety improvement. This study aims to explore and evaluate the difficulties of implementing safety practices in RMAA work. The mixed methods approach was adopted, and semistructured interviews and a two-round Delphi survey were conducted for the data collection. Major difficulties were identified, including limited safety resources for small and medium enterprises (SMEs), difficulty in changing the mindset of RMAA workers, and difficulty in performing safety supervision. These obstacles for implementing safety practices in the RMAA sector, if successfully removed, could significantly improve the safety performance of the RMAA sector and the construction industry as a whole.

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Safety of repair, maintenance, alteration, and addition (RMAA) works have long been neglected because RMAAworks are often minute and only last for a short period of time. With rising importance of the RMAA sector in many developed societies, safety of RMAA works has begun to draw attention. Many RMAA contracting companies are small- and medium-sized enterprises (SMEs) that do not have comprehensive safety management systems. Existing safety legislation and regulations for new construction sites are not fully applicable to RMAAworks. Instead of relying on explicit and well-established safety systems, tacit safety knowledge plays an extremely important role in RMAA projects. To improve safety of RMAAworks, safety knowledge should be better managed. However, safety knowledge is difficult to capture in RMAA works. This study aims to examine safety management practices of RMAA contracting companies to see how safety knowledge of RMAA projects is managed. Findings show that RMAA contracting companies undertaking large-scale RMAA projects have more initiatives of safety management. Safety management of small-scale RMAA works relies heavily on the motivation of site supervisors and self-regulation of workers. Better tacit knowledge management improves safety performance. To enhance safety capability of RMAA contracting companies, a knowledge sharing culture should be cultivated. The government should provide assistance to SMEs to implement proper safety management practices in small-sized projects. Potentials of applying computer software technology in RMAA projects to capture, store, and retrieve safety information should be explored. Employees should be motivated to share safety knowledge by giving proper recognition to those who are willing to share.

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The accident record of the repair, maintenance, minor alteration, and addition (RMAA) sector has been alarmingly high; however, research in the RMAA sector remains limited. Unsafe behavior is considered one of the key causes of accidents. Thus, the organizational factors that influence individual safety behavior at work continue to be the focus of many studies. The safety climate, which reflects the true priority of safety in an organization, has drawn much attention. Safety climate measurement helps to identify areas for safety improvement. The current study aims to identify safety climate factors in the RMAA sector. A questionnaire survey was conducted in the RMAA sector in Hong Kong. Data were randomly split into the calibration and the validation samples. The RMAA safety climate factors were determined by exploratory factor analysis on the calibration sample. Three safety climate factors of the RMAA works were identified: (1) management commitment to occupational health and safety (OHS) and employee involvement, (2) application of safety rules and work practices, and; (3) responsibility for health and safety. Confirmatory factor analysis (CFA) was then conducted on the validation sample. The CFA model showed satisfactory goodness of fit, reliability, and validity. The suggested RMAA safety climate factors can be utilized by construction industry practitioners in developed economies to measure the safety climate of their RMAA projects, thereby enhancing the safety of RMAA works.

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As the biggest expo site in history, construction of the Shanghai Expo site faced a lot of challenges, including involvement of lots of investors, megaconstruction scale, concurrent construction mode, involvement of more than 40,000 migrant workers, and extremely tight completion deadlines, among others. Consequently, these challenges imposed great obstacles on accomplishing the safety, quality, and environmental goals. Through a case study of the Shanghai Expo construction, this paper paper presents the design and implementation of multicriteria incentives in megaprojects to accomplish the safety, quality, and environmental goals. Both quantitative and qualitative findings were triangulated to demonstrate the outcome of the incentives. Six critical success factors (CSFs) for the incentives, rule design, process orientation, top management support, training and promotion, communication in process, and process learning and improvement are identified and validated through case study data and content analysis. It is believed that the findings of this paper can enhance understanding of multicriteria incentive schemes in general and provide insights in implementing these incentive schemes in future megaprojects, particularly in the People’s Republic of China (PRC).

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This paper presents a computational method for eliminating severe stress concentration at the unsupported railhead ends in rail joints through innovative shape optimization of the contact zone, which is complex due to near field nonlinear contact. With a view to minimizing the computational efforts, hybrid genetic algorithm method coupled with parametric finite element has been developed and compared with the traditional genetic algorithm (GA). The shape of railhead top surface where the wheel contacts nonlinearly was optimized using the hybridized GA method. Comparative study of the optimal result and the search efficiency between the traditional and hybrid GA methods has shown that the hybridized GA provides the optimal shape in fewer computational cycles without losing accuracy. The method will be beneficial to solving complex engineering problems involving contact nonlinearity.

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Design-build (DB) is regarded as an effective means of delivering high performance green buildings, and the selection of DB contractors is of critical importance. The objective of this study is to evaluate the selection of design-builders for public buildings seeking Leadership in Energy and Environmental Design (LEED) certification and compare the selection practices involved with those of non-LEED-seeking DB projects through a robust content analysis of 74 DB request for proposals (RFPs) for public DB projects. The results of the content analysis reveal that the level of LEED certification is the dominant means of conveying the sustainability requirements in RFPs for contractor selection, with the majority of RFPs (60%) including sustainability requirements as part of the contractor evaluation package. With the exception of contractors' past performance, there is no statistically significant difference in the importance weightings of selection criteria between LEED-seeking and non-LEED-seeking buildings, and DB owners tend to place more emphasis on innovative technical solutions rather than the past performance of DB contractors. Additionally, the research findings also indicate that owners of LEED-seeking building projects tend to provide less design decisions in RFPs in order to solicit innovative design alternatives from potential DB contractors. This study provides DB owners with a number of practical implications for selecting appropriate design-builders for green DB projects.