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The purpose of this paper is to investigate the effect of an admixture, Swine-waste Bio-char (SB), on the water absorption characteristics of cement pastes.

The effect of SB percentages, heat treatment temperatures, water/binder ratios, and age on the water absorption percentages (WAPs) of SB modified cement pastes were investigated using scanning electron microscopy-energy dispersive spectra, FTIR, Brunauer-Emmett-Teller, and laboratory experiments.

The WAPs of cement pastes with SBs produced at the low treatment temperature (LTT) of 340°C and 400°C were significantly lower (p<0.01) than pastes with SBs produced at the high treatment temperature (HTT) of 600°C and 800°C. This was attributed primarily to the more dominant presence of hydrophobic alkyl surface groups from non-volatilized matter in LTT-SBs. This had also resulted in lower surface areas and pore volumes in LTT-SBs. As a result of the volatilization of these labile hydrophobic groups at HTT, HTT-SBs were more hydrophilic and had higher surface areas and pore volumes. Consequently, HTT-SB pastes had higher WAPs and no significant differences (p<0.05) existed between HTT-SB pastes and control pastes. Also, low water/binder ratios and aging reduced water absorption of SB modified cement pastes.

LTT-SBs reduce water absorption and could reduce concrete deterioration; and as such, associated building repair, maintenance, and adaptation costs. Notably, reductions in concrete water absorption will extend the service life of concrete buildings and infrastructures, particularly in unfavorable environmental conditions. The observed benefits are tempered by the current lack of information on the effects of SB on compression strength, workability, and other durability properties.

SB utilization in concrete buildings will enhance swine-waste disposal and reduce negative environmental impacts on swine farming communities; consequently, improving their quality of life.

Current bio-char research is focused on plant-derived bio-char toward soil remediation and contaminant removal, with very limited applications in concrete. This research advances knowledge for developing livestock-derived bio-char, as a PCRM, toward more sustainable and durable concrete structures.

The purpose of this study is to explore the feasibility of utilizing agricultural (almond shell, rice husk and wood) waste biochars for partial cement replacement by evaluating the relationships between the physiochemical properties of biochars and the early-age characteristics of cement pastes.

Biochars are prepared through the thermal decomposition of biomass in an inert atmosphere. Using varying percentages, biochars are used to replace ordinary Portland cement (OPC) in cement pastes at a water/binder ratio of 0.35. Characterization methods include XPS, FTIR, SEM, TGA, BET, Raman, loss-on-ignition, setting, compression and water absorption tests.

Accelerated setting in biochar-modified cement pastes is attributed to chemical interactions between surface functional groups of biochars and calcium cations from OPC, leading to the early development of metal carboxylate and alkyne salts, alongside the typical calcium-silicate-hydrate (C-S-H). Also, metal chlorides such as calcium chlorides in biochars contribute to the accelerate setting in pastes. Lower compression strength and higher water absorption result from weakened microstructure due to poor C-S-H development as the high carbon content in biochars reduces water available for optimum C-S-H hydration. Amorphous silica contributes to strength development in pastes through pozzolanic interactions. With its optimal physiochemical properties, rice-husk biochars are best suited for cement replacement.

While biochar parent material properties have an impact on biochar properties, these are not investigated in this study. Additional investigations will be conducted in the future.

Carbon/silicon ratio, oxygen/carbon ratio, alkali and alkaline metal content, chlorine content, carboxylic and alkyne surface functional groups and surface areas of biochars may be used to estimate biochar suitability for cement replacement. Biochars with chlorides and reactive functional groups such as C=C and COOH demonstrate potential for concrete accelerator applications. Such applications will speed up the construction of concrete structures and reduce overall construction time and related costs.

Reductions in OPC production and agricultural waste deterioration will slow down the progression of negative environmental and human health impacts. Also, agricultural, manufacturing and construction employment opportunities will improve the quality of life in agricultural communities.

Empirical findings advance research and practice toward optimum utilization of biomass in cement-based materials.

This study aims to investigate the effect of productivity and quality on profitability in the US airline industry.

Airlines operations and performance data were used to determine the effect of productivity and quality on profitability. Correlation and multivariate regression analysis have been used for data analysis.

The results show that labor productivity is the most significant predictor of profitability. On‐time performance has no relationship with profitability. The findings suggest that labor productivity, gas price, average annual maintenance cost and employee salary are significant predictors of profitability. The relationship between labor productivity and employee salary with profitability is positive, while gas price and average annual maintenance cost have a negative relationship with profitability.

The research could be more detailed by taking into account measures of airline safety. Additional measures for service quality could be considered.

Operational performance (labor productivity) is the main source of profitability in the US airline industry followed by customer satisfaction and service quality.

The study captures the performance of the airline industry based on longitudinal data from 1989 to 2008. Previous studies have used either quarterly or monthly observations. Second, the study examines the significance of productivity and quality on profitability. Previous studies have provided little insight regarding the effect of productivity and quality on profitability.

This study aims to develop a production-oriented approach for optimal mass-customisation of floor panel layouts in cross-laminated timber (CLT) buildings. The study enables meeting building clients’ unique floor plan requirements at an optimal cost and simultaneously enhances manufacturers’ profit by minimising material and manufacturing process waste.

The present research uses a hybrid approach consisting of field data collection, mathematical modelling, development of a Genetic Algorithm (GA) and scenario analysis. Field data includes engineered timber production information, design data and building code requirements. The study adopts the Flexible Demand Assignment (FDA) technique to formulate a mathematical model for optimising the design of mass timber buildings and employs GA to identify optimal production solutions. Scenario analysis is performed to validate model outputs.

The proposed model successfully determines the load-bearing wall placement and building spans and specifications of floor panels that result in optimal production efficiency and the desired architectural layout. The results indicate that buildings made of a single category of thickness of panels but customised in various lengths to suit building layout are the most profitable scenario for CLT manufacturers and are a cost-effective option for clients.

The originality of the present study lies in its mathematical and model-driven approach towards implementing mass customisation in multi-storey buildings. The proposed model has been developed and validated based on a comprehensive set of real-world data and constraints.

This study aims to present a comprehensive knowledge mapping and an in-depth analysis of plastic and sustainability research to understand better global trends and directions in this field that emerged between 1995 and 2022.

This study presents a visual analysis of 1933 research articles listed in the Web of Science (WoS) databases between the years 1995 and 2022 related to plastic and sustainability. The knowledge mapping based on CiteSpace and VOSviewer presents the current research status, which contains the analysis of the collaboration network, co-citation network, references with citation bursts and keyword analysis.

The results reveal that China and the USA are the most prominent countries in exploring the notion of sustainability and plastic. The Chinese Academy of Science is the most prominent institution. Chai Qiang, Friedrich Daniel, Sahajwalla Veena and Ok Yong Sik are the most prolific authors in this field. Furthermore, circular economy, bioplastic, sustainable development, polyester and bioplastics are the highly discussed issues in recent years. Not surprisingly, COVID-19 is the latest topic of discussion started in 2021 due to its negative impact on plastic pollution and the challenges it posed to sustainability.

This study is among the pioneers to shed light on the current research status of plastic and sustainability using the bibliometric method and the newest data. This study also suggests that collaborations between scholars and institutions require to be enhanced for better management of plastic pollution and to contribute to sustainable development.