Sustainability assessment of flooring systems in the city of Tehran: An AHP-based life cycle analysis

In recent years, numerous attempts have been made to reduce the global environmental and associated socio-economic impacts of construction activities to achieve sustainable development goals. A sustainable system or activity refers to an eco-friendly, cost effective and socio-politically viable solution. This paper utilizes triple-bottom-line (TBL) sustainability criteria for the selection of a sustainable flooring system in Tehran (Iran). Three types of block joisted flooring systems – concrete, clay, and expanded polystyrene (EPS) blocks – have been investigated using life cycle analysis (LCA). Proposed approach provides a comprehensive evaluation system based on TBL criteria that are further divided into thirteen sub-criteria. It includes: (1) Environmental concerns (resource depletion, waste and emissions, waste management, climate change, environmental risk, embodied energy and energy loss); (2) Economic concerns (material cost, construction cost, and occupation and maintenance cost); and (3) Socio-political issues (social acceptance, vulnerability of area, and building weight). Analytical hierarchy process (AHP) is used as a multi-criteria decision making technique that helps to aggregate the impacts of proposed (sub)criteria into a sustainability index (SI) through a five-level hierarchical structure. Integration of AHP and LCA provides a framework for robust decision making that is consistent with sustainable construction practices. A detailed analysis shows that the EPS block is the most sustainable solution for block joisted flooring system in Tehran.     

An overview of air emission intensities and environmental performance of grey cement manufacturing in Canada

Air emissions generated in grey cement manufacturing originate primarily from the combustion of fossil fuels required to heat the kiln and the chemical reaction of raw materials in the pyroprocessing phase. Given that the kiln system is enclosed, air emissions generated, discharge from a single point source kiln stack. Unlike other industries, the point source kiln stack enables the cement sector to accurately monitor and record total air emissions. The largest contributors to air emissions from grey cement manufacturing are carbon dioxide (CO₂), oxides of nitrogen (NO _x ), sulphur dioxide (SO₂) and dust/particulate matter (PM). In Canada, grey cement manufacturing facilities are required to annually report these emissions through the National Pollutant Release Inventory (NPRI). Since CO₂, NO _x , SO₂ and PM are the largest contributors to air emissions, and Canadian grey cement facilities are required to report these emissions, combining NPRI data with annual grey cement production data allows for the development of intensity-based environmental performance indicators. Based on data provided by NPRI, in combination with industry production, we can better understand the environmental performance of Canada’s grey cement manufacturing. On the global stage, intensity-based performance measures provide a useful tool for comparison and demonstrate a strong environmental performance for grey cement production in Canada. As an energy intensive and trade exposed (EITE) grey cement manufacturing is vulnerable to unbalanced environmental policy, which may ultimately result in leakage of production and air emissions to developing countries.     

Emergy-based life cycle assessment (Em-LCA) for sustainability appraisal of infrastructure systems: a case study on paved roads

Civil infrastructure systems are critical assets that are subjected to damage, service-life deterioration, and increasing maintenance and rehabilitation cost. Effective infrastructure management and principles of sustainable development can help to find an optimal compromise between economic growth and environmental protection for all stakeholders. Colloquially, sustainability refers to meeting triple-bottom-line (TBL) performance objectives including environmental protection, economic prosperity, and social acceptability and equity as a result of short- and long-term policy decisions. In this paper, a comprehensive framework based on the integration of emergy synthesis and life cycle assessment (LCA) has been investigated for a public infrastructure system. The main purpose of the applied method, emergy-based LCA (Em-LCA), is to facilitate an informed decision making process for different asset management scenarios, by identifying and quantifying the attributes of TBL impacts over the life cycle of a civil infrastructure system. As a case study, Em-LCA framework has been applied to evaluate the sustainability of two different scenarios for a road construction project in interior British Columbia, Canada. The results indicate that Em-LCA offers a good understanding to address sustainability issues in infrastructure systems and provides quantitative and transparent results to facilitate informed decision making for asset management.     

Marine Water Quality Assessment Of Synthetic-Based Drilling Waste Discharges

Drilling muds or fluids used in drilling operations serve several functions: they lubricate the drill bit; maintain borehole pressure; clean and condition the hole; and flush rock cuttings to the surface. Drilling mud also adheres to rock cuttings, as can formation oil. Barite is used as a weighting agent, which approximately makes up approximately 33% of synthetic mud. It contains traces of heavy metals, which contribute to the toxicity of drilling waste. As environmental issues attract increasing public awareness, the treatment and disposal of spent drilling fluids and contaminated rock cuttings from drilling operations have become sensitive issues for offshore operations around the world. Within the last decade, the oil and gas industry has introduced synthetic-based drilling fluids as substitutes for oil-based fluids. This pollution prevention measure has been complemented by improvements in solid control systems technology. This paper adopts the current U.S. Environmental Protection Agency methodology for a hypothetical case study of an oil field on the East Coast of Canada to determine the water quality impacts of disposal of drilling wastes. The concentration of pollutants at the edge of the mixing zone in the water column and pore water are estimated and compared with Canadian water quality guidelines for protection of aquatic life.     

Atomic force microscopy and Raman scattering studies of femtosecond laser-induced nanohillocks on CR-39

The phenomenon of nanohillock-like defect formation on the surfaces of CR-39 by ultra-short laser irradiation is investigated using an Atomic Force Microscope (AFM) and Raman Scattering. A polymer CR-39 target was exposed to Ti:sapphire 25-fs laser pulses with a central wavelength at 800 nm. Samples were irradiated for different laser fluences both in air and vacuum. Detailed surface topographical features of the bombarded samples were characterized by atomic force microscopy in contact mode in air at room temperature. AFM reveals that the growth of nanohillocks and their features are strongly dependent on the ambient condition, target position from focus, and irradiation fluence. The appearance of these nanohillocks in the range 1–20 nm in height and 10–90 nm in diameter are regarded as typical features for fast electronic processes (correlated with existence of hot electrons) and are explained on the basis of Coulomb explosion. These nanostructures due to localization of laser energy deposition in small areas provide a possible pathway from dense electronic excitation to atomic motion causing permanent structural modification which are well correlated to structural alterations, like crosslinking and chain scissions, inferred from Raman spectroscopy.     

On the Issue of Incomplete and Missing Water-Quality Data in Mine Site Databases: Comparing Three Imputation Methods

Large water-quality databases are valuable for predicting mine drainage chemistry, identifying optimal measures for mitigation and remediation, and refuting/refining models and theories. However, such databases often have missing values due to periodic lack of sampling and analysis or input errors. These missing values lead to problems in machine learning and statistical analysis of water-quality data from mine sites. Using water-quality data collected from 1971 to 1994 from many locations at a copper-molybdenum-gold-silver-rhenium mine site, we compared three imputation methods to estimate missing water-quality data: iterative robust model-based imputation (IRMI), multiple imputations of incomplete multivariate data (AMELIA), and sequential imputation for missing values (IMPSEQ). These methods were evaluated based on mean absolute error, relative absolute error, and percent bias techniques. The results showed that IMPSEQ and IRMI are suitable to impute missing values in water-quality databases at mine sites, whereas AMELIA is not.     

Attitudes towards mobile banking: are there any differences between users and non-users?

Extant research has focused on monitoring the behaviour of people who use mobile banking (MB) but it has paid little attention to understanding the impact of information technology usage behaviour due to cultural differences. Humans are the weakest link in information technology adoption; past research has shown that not all users are predisposed to change their behaviour radically and adopt new channels of banking. This paper examines the demographic patterns of users and non-users of MB. The paper also investigates the attitudinal influences of users and non-users of MB based on innovation attributes. Using empirical research, the study identifies constructs of innovation attributes that were perceived to be significantly different among the users and non-users of MB. The study provides valuable insights into MB in Saudi Arabia that have not been previously investigated. From a practical point, findings of this study will be particularly useful to banks, financial institutions and telecommunication service providers.