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Purpose Public–private partnership (PPP) has been adopted in many areas especially within the architecture, engineering and construction research domain. However, the PPP in critical infrastructure resilience (CIR) has not received the needed attention even though it has been acclaimed to be the panacea for building infrastructure resilience. This paper aims to adopt a systematic review to proactively identify the risks factors that pertains to using PPP as a mechanism to build the resilience of critical infrastructure. Design/methodology/approach Using a systematic methodology, a total record of 51 academic publications and 5 institutional reports from reputable organizations were identified and analyzed. Findings The selected literature was subjected to content analysis to retrieve 46 risk factors in PPP in CIR. The outcome of the systematic revealed the topmost risks as corruption, natural and unavoidable catastrophes, wars, terrorism, sabotage, cost overrun issues, a lack of centralized mechanism for coordinating integrated actions, inconsistent government policies, inadequate supervision, high operational cost due to robust and redundant measure, lack of supporting infrastructure, lack of open and integrated communication, unstable government, political interference, lack of PPP experience and legislation change. A conceptual framework was developed by grouping the identified risks under 13 categories. Research limitations/implications The outcome of this study will be a guide for decision makers and stakeholders with the responsibility of building the resilience of critical infrastructure. Originality/value The study contributes to CIR research area by providing an in-depth knowledge on risks that are inherent in PPP in CIR.

In recent years, rapid urbanisation has caused a large volume of construction and demolition waste in China. Although China has introduced some documents and policies to manage the waste, these documents are not operable or detailed enough to guide the practice further. It is of great importance to analyse critical success factors (CSFs) that could contribute to the successful development of construction and demolition waste management in China. A survey questionnaire was delivered to 150 participants, with 121 responses returned. Eighteen CSFs were identified and evaluated. The results showed that five factors – namely, ‘polluter-pays principle’, ‘subsidies for recycling activities’, ‘waste minimisation at the planning stage’, ‘value-added tax deduction’ and ‘penalties on violations’ – were considered the most important factors. Additionally, differences among the perspectives of three groups of related stakeholders (researchers, industry practitioners and government officers) on the criticality of the 18 CSFs were investigated. ‘City plan for land use’ was considered to have significant disagreement among researchers and government officers. However, the perceptions of industry practitioners were significantly different from those of researchers and government officers. The disagreements might be caused by the different interests, needs and objectives of related stakeholders. The findings of this study will likely prompt the policymakers in China to consider relevant CSFs to enhance the performance of construction and demolition waste management.

Occupant behaviour (OB) is impacted by several interdisciplinary factors: environmental, psychosocial, cultural and economic. One of these impacting factors is the climate. In this study, the patterns of OB interactions with heating, cooling, lighting, equipment, windows and shading collected in questionnaire surveys were used as input data in the simulation models of two university buildings. The buildings, a green-rated and a non-rated one, are in Western Sydney University in Sydney, Australia. Then, the models were simulated in eight different climate zones in Australia. Therefore, this research aimed to understand how different climate zones may impact the energy related to OB and compare this impact between a green-rated building and a building without any rating. The results showed that there is no correlation between climate and OB and the levels of discomfort are related to the cooling season. The green building is less subjected to external changes, indicating that in buildings with automatic and properly controlled centralised management systems, the impacts related to the misuse of energy due to OB would be almost irrelevant. The results of this study should not be extended to other occupant behavioural patterns or situations. The results should be confined within the present research and context.

PurposeThis paper proposes an intact framework for building life cycle energy estimation (LCEE), which includes three major energy sources: embodied, operational and mobile.Design/methodology/approachA systematic review is conducted to summarize the selected 109 studies published during 2012–2021 related to quantifying building energy consumption and its major estimation methodologies, tools and key influence parameters of three energy sources.FindingsResults show that the method limitations and the variety of potential parameters lead to significant energy estimation errors. An in-depth qualitative discussion is conducted to identify research knowledge gaps and future directions.Originality/valueWith societies and economies developing rapidly across the world, a large amount of energy is consumed at an alarming rate. Unfortunately, its huge environmental impacts have forced many countries to take energy issues as urgent social problems to be solved. Even though the construction industry, as the one of most important carbon contributors, has been constantly and academically active, researchers still have not arrived at a clear consensus for system boundaries of life cycle energy. Besides, there is a significant difference between the actual and estimated values in countless current and advanced energy estimation approaches in the literature.

In this study, an experimental investigation was conducted to understand the failure mechanism of geopolymeric recycled aggregate concrete (GRAC) under compression. GRAC specimens with different recycled aggregate (RA) replacement ratios were prepared and tested. A digital image correlation (DIC) system was used to monitor the displacement field and strain distribution over the surface of the specimen. The results revealed that RA replacement adversely affected the mechanical properties of geopolymeric concrete, including compressive strength, elastic modulus, and splitting tensile strength. For all the specimens, cracks mainly initiated near the interfacial transition zones, and usually nucleated around natural aggregate (NA) rather than RA. As observed from the final crack patterns, it was more frequent for the RA that cracks passed through the aggregate particles, in comparison with the NA. The location of strain concentration region detected by the DIC method was closely consistent with that of the formed macro cracks.

Selecting suitable construction designs for efficient energy management and moderating greenhouse gas emissions regarding to a construction project's life-cycle of are typically demanding to design...

This study aims to investigate the combined influence of varying concentration of waste steel fibre and fly ash on rheological and mechanical performance of fibre-reinforced concrete (FRC). Cement ...

The present study examines the development of a push-pull ventilation system with localized extraction located for use in wastewater treatment. The proposed approach aims to minimize the concentrat...

Worldwide the construction industry presents a significant demand for new technologies ensuring certainty, cost-effectiveness and time efficiency. Modern construction relies on digital resources, a...

Perceptions of occupants to energy use, collected in questionnaire surveys, were used as input variable for building simulations. These perceptions are related to occupant interactions with lightin...

Purpose The growth in ageing population globally has led to the increase in demand for retirement or aged care homes. Adopting public–private partnership (PPP) in the global retirement village market has become the new approach to address some of the emerging challenges. This paper aims to explore and analyse the critical success factors (CSFs) for the adoption of PPP in the global retirement village market. Design/methodology/approach An empirical questionnaire survey was conducted with experienced practitioners in the global PPP and retirement village markets. Mean score analysis, normalization range method, Kendall’s coefficient of concordance and factor analysis were used for analysis. Findings Results show that out of the 27 CSFs identified, the most significant ones in developing PPP retirement village projects are “the age-friendly design of villages”, “appropriate location of PPP retirement village”, “reliable and accessible health and physical facilities” and “effective social inclusion and integration in villages”. Further analysis shows that the 27 CSFs can be grouped into 7 major factor groupings, namely, “effective project monitoring”, “financial support”, “social integration”, “effective contractual arrangement between parties”, “government commitment and support”, “sustainable design of village” and “effective payment structure”. Originality/value The outputs of this study will adequately inform retirement village developers, retirement village stakeholders and local government authorities of the best practices they should put in place to ensure the sustainable growth of the global retirement village market.

Building’s window-to-wall ratio (WWR) plays a significant role for predicting energy consumption in tropical climate because huge amount of solar heat gain occurs through the exterior windows for h...

The physical and mechanical properties of high-strength lightweight concrete were investigated considering various parameters including mixture design proportions, dosages and types of superplasticiser and silica fume and cement content aiming at a design strength of 45 MPa. The experimental results of density, tensile strength, modulus of elasticity and efficiency factor (ratio of compressive strength to density) were compared with empirical equations previously proposed in the literature. In earlier studies, using expanded clay coarse aggregate of maximum size 25 mm, the lightweight concrete presented a maximum strength of 30 MPa and an efficiency factor of 18·9 MPa.dm3/kg. By reducing the maximum size to 9·5 mm, a higher compressive strength of approximately 46·9 MPa and an efficiency factor of 28·3 MPa.dm3/kg were obtained. However, using expanded shale coarse aggregate yielded higher values of compressive strength and efficiency factor at 64·3 MPa and 36·3 MPa.dm3/kg, respectively. The replacement of coarse expanded clay aggregate with expanded shale resulted in a high-strength lightweight aggregate concrete with the best properties in this study: fc28 = 64·3 MPa, a density of 1·77 kg/dm3 and an efficiency factor of 36·3 MPa.dm3/kg.

PurposeOccupants are one of the most impacting factors in the overall energy performance of buildings, according to literature. Occupants’ behaviours and actions may impact the overall use of energy in more than 50%. In order to quantify the impact that occupant behaviour has in the use of energy, this study simulated interactions between occupants and the systems present in two actual buildings. The main aim was to compare the deviations due to occupant behaviour with the actual conditions and energy use of the two buildings.Design/methodology/approachThe buildings used as a case study in this research were green buildings, rated according to the Australian Green Star certification system as a 6-star and a non-rated building. The two buildings are university buildings with similar characteristics, from Western Sydney University, in Sydney, Australia. A comparison was performed by means of building simulations among the use of energy in both buildings, aiming to understand if the green rating had any impact on the energy related to occupant behaviour. Therefore, to represent the actual buildings' conditions, the actual data related with climate, geometry, systems, internal loads, etc. were used as input variables in the simulation models of the green and the non-rated buildings. Both models were calibrated and validated, having as target the actual monitored use of electricity.FindingsOccupants were categorized according to their levels of energy use as follows: saving, real and intensive energy users. Building simulations were performed to each building, with varying parameters related with lighting, plug loads, windows/doors opening, shading and air conditioning set points. Results show that occupant behaviour may impact the buildings' energy performance in a range of 72% between the two extremes. There is no significant relationship between the green rating and the way occupants behave in terms of the energy use.Originality/valueThis study intends to show the impact of different categories of occupant behaviour in the overall energy performance of two university buildings, a non-rated and a green-rated building, having as reference an actual representation of the buildings. Additionally, the study aims to understand the main differences between a green-rated and a non-rated building when accounting with the previous categories.

‘Resilience Engineering (RE)’ is a paradigm shift, a discipline, a theory which can be pursuited with a variety of approaches for proactive safety management, which can help the adopted organizatio...

The effects of strength grades, loading modes, and stress levels on the performance deterioration of sustainable recycled aggregate concrete (RAC) subjected to mechanical loading or coupled mechani...

The aim of this study was to determine the effect of zinc supplementation on anthropometric measures. In this systematic review and dose–response meta-analysis, we searched PubMed, Scopus, ISI Web of Science, and the Cochrane Library from database inception to August 2018 for relevant randomized controlled trials. Mean differences and SDs for each outcome were pooled using a random-effects model. Furthermore, a dose–response analysis for zinc dosage was performed using a fractional polynomial model. Quality of evidence was evaluated using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology. Twenty-seven trials (n = 1438 participants) were included in the meta-analysis. There were no significant changes in anthropometric measures after zinc supplementation in the overall analysis. However, subgroup analyses revealed that zinc supplementation increased body weight in individuals undergoing hemodialysis (HD) [3 trials, n = 154 participants; weighted mean difference (WMD) = 1.02 kg; 95% CI: 0.38, 1.65 kg; P = 0.002; I(2) = 11.4%] and decreased body weight in subjects who are overweight/obese but otherwise healthy (5 trials, n = 245 participants; WMD = −0.55 kg; 95% CI: −1.06, −0.04 kg; P = 0.03; I(2) = 31.5%). Dose–response analyses revealed a significant nonlinear effect of supplementation dosage on BMI (P = 0.001). Our data suggest that zinc supplementation increases body weight in patients undergoing HD and decreases body weight in individuals who are overweight/obese but otherwise healthy, although after normalization for study duration, the association observed in subjects who are overweight/obese disappeared. Although more high-quality studies are needed to reach a definitive conclusion, our study supports the view that zinc may be associated with body weight.

Thermal insulation is a significant factor in building construction. As a result, Green Star in Australia requires building envelopes to be insulated properly. Further, green buildings require at least 15% above the required R-values (which are measured in m2 K/W) for achieving Green Star credit points. Thermal insulation of the roof depends on various factors such as insulation material, sarking material, air films and roof covering. Therefore, there are many options with different combinations available to obtain the required total R-values. This research aims to identify optimum solutions for roofing solutions considering the life-cycle cost. There are ten commonly used roof types in Australia. Therefore, this research calculated the life-cycle costs using the net present value technique for more than 2000 options of roofing solutions and selected optimum solutions for each climate zone in Australia. The outcome shows that the initial cost and the replacement cost significantly influence the life-cycle cost. Further, the maintenance, replacement and disposal costs vary from 47 to 69% of the life-cycle cost. Sensitivity analysis concludes that the discounting rate has a significant influence on the life-cycle cost of the roofing solution. However, the changes in labour rate have only a slight impact on the life-cycle cost of roofing solutions.

Purpose Addressing global warming challenge, carbon emissions reduction potential of the construction industry has received additional attentions. The decoupling of construction industry and carbon emissions through policies, technologies and model innovations is an effective way for reducing environmental pollution and achieve eco-urban target. The paper aims to discuss these issues. Design/methodology/approach Within the scope of green building carbon emissions (GB-CO2) research, a large number of scientific literature has been published in construction discipline over the past few decades. However, it seems that a systematic summary of strategies, techniques, models and scientific discussion of future direction of GB-CO2 is lacking. Therefore, this paper carries out data mining on authoritative journals, identified the key research topics, active research areas and further research trends through visualization studies. Findings This study contributes to the body of knowledge in GB-CO2 by critically reviewing and summarizing: professional high-quality journals have a greater influence in the scope of research, developed countries and developing countries are all very concerned about sustainable buildings, and the current hot topics of research focus on the application of the life cycle models, energy efficiency, environmental performance of concrete material, etc. Moreover, further research areas that could expand the knowledge of cross-national long-term carbon mechanisms, develop comprehensive life cycle carbon emissions assessment models, build technical standards and tests for the sustainable building material and systems, and exploit multi-objective decision models considering decarbonizing design and renewable energy. Originality/value This study is of value in systematic insight the state-of-the-art of GB-CO2 research in the more recent decade. A more vividly and effectively method is documented in extending the traditional bibliometric review to a deeper discussion. This study can also benefit construction practitioners by providing them a focused perspective of strategy and technologies innovations for emerging practices in green building projects.

Current wireless secrecy research in the literature has mainly been performed for one wiretapper under correlated fading. In this paper, a new wireless secrecy framework for multiple wiretappers under multivariate exponentially-correlated (exp.c.) Nakagami- $m$ fading is proposed. Using the distribution of multivariate exp.c. Nakagami- $m$ fading, new, exact, and compact expressions for the ergodic secrecy capacity, and secrecy outage probability (SOP) under multiple wiretappers are obtained for an integer fading parameter $m$ . A secrecy analysis is also performed for the first time in this paper using an adaptive on/off transmission encoder under multivariate exp.c. Nakagami- $m$ fading. A secrecy analysis with three wiretappers under quadrivariate exp.c. Nakagami- $m$ fading is also given, which shows the effectiveness of the new framework. Simulation results are shown to exactly match theoretical predictions.

Despite the importance of proper risk management during the construction execution stage, the current studies mainly focus on risk management at the planning stage. In order to effectively manage risks and accomplish a project success, it is instrumental to manage and mitigate risks at the execution stage where the most of risks are actually occurred. Hence, this research aims to identify the most critical success factors for effective risk management at the execution stage of a construction project. A mixed method was adopted to identify the priorities among various success factors for risk management through a questionnaire survey, and follow-up interviews were conducted to retrieve more insights and lessons learnt from construction professionals. Total 55 construction professionals responded that a) Project management capacity; b) knowledge and experience; c) early involvement of contractors and d) socio-cultural forces are the most critical success factors for successful risk management during the execution stage. This research identified the critical success factors and its relative importance expected to provide a means for the construction professionals to prioritise critical success factors for risk management at the execution stage, and it will serve a risk management supporting tool to make a proper plan and decision on risks. Refereed/Peer-reviewed

Context Rare partial/complete loss-of-function mutations in the melanocortin-4 receptor (MC4R) gene are the most common cause of Mendelian obesity in European populations, but their contribution to obesity in the Mexican population is unclear. Objective and Design We investigated whether deleterious mutations in MC4R contribute to obesity in Mexican children and adults. Results We provide evidence that the MC4R p.Ile269Asn (rs79783591) mutation may have arisen in modern human populations from a founder event in native Mexicans. The MC4R Isoleucine 269 is perfectly conserved across 184 species, which suggests a critical role for the amino acid in MC4R activity. Four in silico tools (SIFT, PolyPhen-2, CADD, MutPred2) predicted a deleterious impact of the p.Ile269Asn substitution on MC4R function. The MC4R p.Ile269Asn mutation was associated with childhood (Ncontrols = 952, Ncases = 661, odds ratio (OR) = 3.06, 95% confidence interval (95%CI) [1.94–4.85]) and adult obesity (Ncontrols = 1445, Ncases = 2,487, OR = 2.58, 95%CI [1.52–4.39]). The frequency of the MC4R p.Ile269Asn mutation ranged from 0.52 to 0.59% and 1.53 to 1.59% in children and adults with normal weight and obesity, respectively. The MC4R p.Ile269Asn mutation co-segregated perfectly with obesity in 5 multigenerational Mexican pedigrees. While adults with obesity carrying the p.Ile269Asn mutation had higher BMI values than noncarriers, this trend was not observed in children. The MC4R p.Ile269Asn mutation accounted for a population attributable risk of 1.28% and 0.68% for childhood and adult obesity, respectively, in the Mexican population. Conclusion The MC4R p.Ile269Asn mutation may have emerged as a founder mutation in native Mexicans and is associated with childhood and adult obesity in the modern Mexican population.

Due to the rapid growth of the ageing population and the shrinking of family size in China, there has been a steady increase in the demand for nursing homes. The Chinese government has encouraged the development of nursing homes. However, there is no clear understanding of the thermal environment of nursing homes and the thermal comfort of their residents. Therefore, this paper describes a pilot study that was undertaken to investigate the thermal comfort of senior residents living in nursing homes. A wireless sensor network system was developed to continuously monitor the thermal environment of nursing homes for an entire year. Site measurements and a questionnaire also were conducted. The results revealed significant seasonal variations in the thermal environment of nursing homes and in the thermal comfort, thermal sensation and adaptive behaviours of older adults. The calculation of thermal comfort was modified according to the older adults’ behaviour patterns. The knowledge acquired in this initial study will enrich knowledge of the thermal comfort of older adults living in nursing homes. It also will provide preliminary insights for caregivers, designers and policymakers in their efforts to deliver a more comfortable, healthy and sustainable environment in nursing homes in China.