A recent study suggested that buildings globally consume up to 40% of energy and responsible for half of world greenhouse gas emission. Introducing life cycle assessment (LCA) to the building ...industry is important because it can measure every environmental impact involved in every process from cradle to grave systematically. Within the last decade, research on LCA has increased covering from construction process to manufacturing of building materials. The methods to assess buildings are diverse as buildings have different functions, materials, sizes and locations. The aim of this article is to review the LCA methods and to distinguish phases and materials that affect significantly to environment. The findings show the methods are based on ISO 14040 series with variance to suit different scopes, aims and limitations. The operational phase is identified to consume the highest energy and concrete responsible for the highest embodied energy. The findings also suggested that building material with lower embodied energy does not necessarily have lower life cycle energy. Therefore, implementation of LCA can determine and mitigate the environmental impacts in the development stage thus promoting sustainability in building industry.
Research on agricultural wastes management, as a natural resource material, is state of the art and desirable subject in many engineering subcategories. The benefits include ease of access and ...implementation, affordability and environmental friendliness. Optimal use of agricultural wastes has always been a concern for humans, and the utilization of them for various purposes is an efficient way of environmental management. Among bio-waste ashes, some of them such as rice husk ash has a high pozzolanic content that stems from their abundant silica concentration. The significantly low reaction time and the high utilization of these materials, when compared to traditional mechanical methods, has generated interest from researchers. The present paper surveys the experimental studies of biomass waste ash as a pozzolanic additive for engineering applications. This paper initially provides some essential background information includes agricultural waste ash preparation procedures and its composition, then reviews the various physical and chemical pretreatment methods. Finally, the paper explores the potential application of rice husk ash as green and sustainable material in various industries.
•The Rice husk is an agricultural residue can use as natural resources.•The use of RHA contributes to economic and environmental benefits.•RHA can potentially stabilize the soil and reduce construction cost.•RHA as a raw material can use as adsorbent or catalyst for biodiesel production.
AbstractChemical stabilization is commonly used to improve engineering properties of problematic soils. This study investigates the possibility of using calcium carbide residue (CCR), a by-product of ...the acetylene production process, to improve engineering properties of clays. For this purpose, an array of unconfined compressive strength (UCS) and consolidation tests is performed on green bentonite (with predominantly montmorillonite mineralogy) and white kaolin (with predominantly kaolinite mineralogy) to assess strength and compressibility of the stabilized clays with different CCR dosages and at various curing times. Furthermore, a suite of microlevel tests characterizes the microstructural properties of the stabilized clay matrices to provide further insight into the mechanism of strength development. Microlevel assessments are performed using field emission scanning electron microscopy (FESEM), X-ray fluorescence (XRF), particle size analysis (PSA), and nitrogen-based Brunauer-Emmett-Teller (N2-BET) surface-area analysis tests. The experimental results suggest that CCR can significantly improve the strength and compressibility characteristics of the tested clays. The highest strength improvements are attained with 9 and 12% of CCR for the tested bentonite and kaolin, respectively. Furthermore, the UCS values from the current study are compared with those reported in the literature for the same clays stabilized with several traditional and nontraditional additives. Microlevel observations delineate the formation of new cementing materials that result from chemical reactions between CCR and clay minerals. Less-porous and denser soil fabrics are seen on the surface of clay particles. Findings of this study confirm the potential of CCR as a sustainable alternative to traditional stabilizers for soil improvement purposes in civil engineering applications.
Purpose
The purpose of this paper is to advance knowledge on the implications of perceived corporate social responsibility (CSR) on employee levels of commitment and citizenship behaviour (OCB) by ...investigating a trust-based mediational process in the context of academia.
Design/methodology/approach
The research data are collected from a sample of 736 academics through a questionnaire based survey administered in different Pakistani universities. The nature of trust-based mechanism underlying the relationships between CSR, affective commitment and OCB is determined through structural equation modelling of the research data.
Findings
The findings suggest that the perceived CSR is an important predictor of academics’ attitudes and behaviour in universities. Whilst the findings implicate the mediating role of trust in the process by which perceived CSR influences academics’ commitment, trust does not appear to mediate the perceived CSR’s relationship with OCB.
Research limitations/implications
This study utilises single-sourced and cross-sectional data, which may have resulted in common method bias.
Practical implications
By furnishing evidence of the beneficial effects of perceived CSR on academics’ levels of trust, commitment and citizenship behaviour, this study provides a business case for universities’ involvement in CSR. The findings are particularly useful to academic administrators and managers who are interested in nurturing positive attitudes and behaviours amongst academic staff.
Originality/value
There is a paucity of research on CSR in the academic work settings of developing countries. This is the first study to examine the trust-based microfoundation of CSR in the context of academia in Pakistan.
Stability of the soil slopes is one of the most challenging issues in civil engineering projects. Due to the complexity and non-linearity of this threat, utilizing simple predictive models does not ...satisfy the required accuracy in analysing the stability of the slopes. Hence, the main objective of this study is to introduce a novel metaheuristic optimization namely Harris hawks’ optimization (HHO) for enhancing the accuracy of the conventional multilayer perceptron technique in predicting the factor of safety in the presence of rigid foundations. In this way, four slope stability conditioning factors, namely slope angle, the position of the rigid foundation, the strength of the soil, and applied surcharge are considered. Remarkably, the main contribution of this algorithm to the problem of slope stability lies in adjusting the computational weights of these conditioning factors. The results showed that using the HHO increases the prediction accuracy of the ANN for analysing slopes with unseen conditions. In this regard, it led to reducing the root mean square error and mean absolute error criteria by 20.47% and 26.97%, respectively. Moreover, the correlation between the actual values of the safety factor and the outputs of the HHO–ANN (
R
2
= 0.9253) was more significant than the ANN (
R
2
= 0.8220). Finally, an HHO-based predictive formula is also presented to be used for similar applications.
Carbon emissions from the peat fire problem—a review Che Azmi, Nor Azizah; Mohd Apandi, Nazirah; A. Rashid, Ahmad Safuan
Environmental science and pollution research international,
04/2021, Letnik:
28, Številka:
14
Journal Article
Recenzirano
Peat fires in tropical peatland release a substantial amount of carbon into the environment and cause significant harm to peatlands and the ecology, resulting in climate change, biodiversity loss, ...and the alteration of the ecosystem. It is essential to understand peat fires and to develop more effective methods for controlling them. To estimate carbon emissions and monitor fires, the depth of burning can measure the overall burnt down the volume, which is proportional to the carbon emissions that are emitted to the environment. The first step is to understand the technique of measuring the depth of the burn. However, there is a lack of integrated information regarding the burning depth for peat fires. This review paper discusses the techniques used to measure the burning depth, with particular attention given to quantifying carbon emissions. The article also provides information on the types of methods used to determine the burning depths. This research contributes to the field of peat fire by providing a readily available reference for practitioners and researchers on the current state of knowledge on peat fire monitoring systems.
AbstractResearch on the utilization of recycled concrete aggregate (RCA) in civil engineering applications is gaining popularity worldwide due to the increased efforts to promote preservation of the ...environment and sustainable development. Recycled concrete aggregate concrete is, however, presently still limited to nonstructural applications. Recycled concrete aggregate concrete can still be considered as a rigid pavement material when its flexural strength is improved adequately to sustain future traffic loads. In this study, polyvinyl alcohol (PVA), a water-soluble polymer, was used to improve the flexural strength of RCA concrete. The influence of PVA-to-cement (p/c) and water-to-cement (w/c) ratios on the compressive and flexural strengths of RCA-PVA concrete was investigated via scanning electron microscopy (SEM) and X-ray diffraction (XRD). Polyvinyl alcohol films were found to retard the hydration process, resulting in the delay in initial and final setting times of cement-PVA paste, therefore reducing the compressive strength of RCA-PVA concrete. For all the w/c ratios tested, the flexural strength increased with increasing p/c ratios up to an optimum p/c ratio that provided the highest flexural strength, followed by a subsequent decrease beyond this peak value. The optimum p/c ratio tended to increase with an increase in w/c ratio, being 0.5, 0.5, 1.0, and 1.5 for w/c ratios of 0.3, 0.4, 0.5, and 0.6, respectively. Based on the requirements of the Department of Highways, Thailand, the p/c ≤1 at w/c ≤0.5 was found to be suitable for developing RCA-PVA concrete for rigid pavements. The outcome of this research confirms the viability of using PVA to improve the flexural strength of RCA concrete for usage as a sustainable rigid pavement material.
In this research, the novel metaheuristic algorithm Harris hawks optimization (HHO) is applied to landslide susceptibility analysis in Western Iran. To this end, the HHO is synthesized with an ...artificial neural network (ANN) to optimize its performance. A spatial database comprising 208 historical landslides, as well as 14 landslide conditioning factors-elevation, slope aspect, plan curvature, profile curvature, soil type, lithology, distance to the river, distance to the road, distance to the fault, land cover, slope degree, stream power index (SPI), topographic wetness index (TWI), and rainfall-is prepared to develop the ANN and HHO-ANN predictive tools. Mean square error and mean absolute error criteria are defined to measure the performance error of the models, and area under the receiving operating characteristic curve (AUROC) is used to evaluate the accuracy of the generated susceptibility maps. The findings showed that the HHO algorithm effectively improved the performance of ANN in both recognizing (AUROC
= 0.731 and AUROC
= 0.777) and predicting (AUROC
= 0.720 and AUROC
= 0.773) the landslide pattern.
Artificial neural network (ANN) aimed to simulate the behavior of the nervous system as well as the human brain. Neural network models are mathematical computing systems inspired by the biological ...neural network in which try to constitute animal brains. ANNs recently extended, presented, and applied by many research scholars in the area of geotechnical engineering. After a comprehensive review of the published studies, there is a shortage of classification of study and research regarding systematic literature review about these approaches. A review of the literature reveals that artificial neural networks is well established in modeling retaining walls deflection, excavation, soil behavior, earth retaining structures, site characterization, pile bearing capacity (both skin friction and end-bearing) prediction, settlement of structures, liquefaction assessment, slope stability, landslide susceptibility mapping, and classification of soils. Therefore, the present study aimed to provide a systematic review of methodologies and applications with recent ANN developments in the subject of geotechnical engineering. Regarding this, a major database of the web of science has been selected. Furthermore, meta-analysis and systematic method which called PRISMA has been used. In this regard, the selected papers were classified according to the technique and method used, the year of publication, the authors, journals and conference names, research objectives, results and findings, and lastly solution and modeling. The outcome of the presented review will contribute to the knowledge of civil and/or geotechnical designers/practitioners in managing information in order to solve most types of geotechnical engineering problems. The methods discussed here help the geotechnical practitioner to be familiar with the limitations and strengths of ANN compared with alternative conventional mathematical modeling methods.
Over the past years, numerous Internet of Things (IoT)-based healthcare systems have been developed to monitor patient health conditions, but these traditional systems do not adapt to constraints ...imposed by revolutionized IoT technology. IoT-based healthcare systems are considered mission-critical applications whose missing deadlines cause critical situations. For example, in patients with chronic diseases or other fatal diseases, a missed task could lead to fatalities. This study presents a smart patient health monitoring system (PHMS) based on an optimized scheduling mechanism using IoT-tasks orchestration architecture to monitor vital signs data of remote patients. The proposed smart PHMS consists of two core modules: a healthcare task scheduling based on optimization and optimization of healthcare services using a real-time IoT-based task orchestration architecture. First, an optimized time-constraint-aware scheduling mechanism using a real-time IoT-based task orchestration architecture is developed to generate autonomous healthcare tasks and effectively handle the deployment of emergent healthcare tasks. Second, an optimization module is developed to optimize the services of the e-Health industry based on objective functions. Furthermore, our study uses Libelium e-Health toolkit to monitors the physiological data of remote patients continuously. The experimental results reveal that an optimized scheduling mechanism reduces the tasks starvation by 14% and tasks failure by 17% compared to a conventional fair emergency first (FEF) scheduling mechanism. The performance analysis results demonstrate the effectiveness of the proposed system, and it suggests that the proposed solution can be an effective and sustainable solution towards monitoring patient’s vital signs data in the IoT-based e-Health domain.
PDF
