Impact of Fomes fomentarius growth on the mechanical properties of material extrusion additively manufactured PLA and PLA/Hemp biopolymers.

Objective: This article aims to analyze and revalidate the available scientific evidence on the impact of sustainable practices in construction and its environmental impacts. Theoretical framework: Civil construction plays a crucial role in economic and social development, however, its activities cause significant environmental impacts. Construction activities use large amounts of natural resources, such as water, wood, sand and minerals. Method: The present study is based on an exploratory and analytical perspective, with the aim of investigating in detail the connection between environmental sustainability and the impacts of civil construction. Databases such as: Scielo, Scopus and Web of Science were used, using specific keywords related to sustainability and civil construction. Results and conclusion: The studies reveal that the incorporation of sustainable practices in civil construction is an urgent and viable need. The effectiveness of these practices has shown positive results in reducing impacts, demonstrating that it is possible to align development with environmental responsibility. Research Implications: The results of this investigation offer valuable insights for designing sustainable government policies. The findings highlight the relevance of prioritizing and reinforcing sustainable practices in construction. Originality/value: The study incorporates a diverse range of relevant theories, ranging from environmental theories to construction models focused on consumerist practices. This comprehensive methodology offers a broader and more detailed view of the intersection between sustainability and civil engineering.

Polycarbonate-based nanocomposites were developed herein through a material extrusion (MEX) additive manufacturing (AM) process. The fabrication of the final nanocomposite specimens was achieved by implementing the fused filament fabrication (FFF) 3D printing process. The impact of aluminum nitride (AlN) nanoparticles on the thermal and mechanical behavior of the polycarbonate (PC) matrix was investigated thoroughly for the fabricated nanocomposites, carrying out a range of thermomechanical tests. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) provided information about the morphological and surface characteristics of the produced specimens. Using energy dispersive spectroscopy (EDS), the elemental composition of the nanocomposite materials was validated. Raman spectroscopy revealed no chemical interactions between the two material phases. The results showed the reinforcement of most mechanical properties with the addition of the AlN nanoparticles. The nanocomposite with 2 wt.% filler concentration exhibited the best mechanical performance overall, with the highest improvements observed for the tensile strength and toughness of the fabricated specimens, with a percentage of 32.8% and 51.6%, respectively, compared with the pure polymer. The successful AM of PC/AlN nanocomposites with the MEX process is a new paradigm, which expands 3D printing technology and opens a new route for the development of nanocomposite materials with multifunctional properties for industrial applications.

Herein, polytetrafluoroethylene (PTFE) is evaluated as a reinforcement agent in material extrusion (MEX) additive manufacturing (AM), aiming to develop nanocomposites with enhanced mechanical performance. Loadings up to 4.0 wt.% were introduced as fillers of polylactic acid (PLA) and polyamide 12 (PA12) matrices. Filaments for MEX AM were prepared to produce corresponding 3D-printed samples. For the thorough characterization of the nanocomposites, a series of standardized mechanical tests were followed, along with AFM, TGA, Raman spectroscopy, EDS, and SEM analyses. The results showed an improved mechanical response for filler concentrations between 2.0 and 3.0 wt.%. The enhancement for the PLA/PTFE 2.0 wt.% in the tensile strength reached 21.1% and the modulus of elasticity 25.5%; for the PA12/PTFE 3.0 wt.%, 34.1%, and 41.7%, respectively. For PLA/PTFE 2.0 wt.%, the enhancement in the flexural strength reached 57.6% and the modulus of elasticity 25.5%; for the PA12/PTFE 3.0 wt.%, 14.7%, and 17.2%, respectively. This research enables the ability to deploy PTFE as a reinforcement agent in the PA12 and PLA thermoplastic engineering polymers in the MEX AM process, expanding the potential applications.

Strain rate sensitivity metrics of PSU and PPSU high-performance polymers in extrusion-based additive manufacturing

ABSTRACTTo better meet global sustainable development goals will require more focus on Arab countries like Kuwait, which contribute one and a half times more global greenhouse gas emissions per capita than the United States. Buildings contribute more than half of these emissions. Rating systems like LEED and BREEAM can help reduce energy emissions from buildings globally when used during construction, but these rating systems are not entirely applicable to Kuwait as they are not tailored for its geographic climate and social context, and there is currently no rating system tailored for energy efficient and environmentally sustainable buildings. The research presented in this paper measures the industry's perceptions about sustainable design and construction practices in Kuwait. A synthesized list of sustainable design and construction principles were developed from the six most common rating systems globally that are currently being used in the Arab region. Construction professionals (n = 131) from Kuwait were asked in a qualitative survey which sustainable design principles and construction practices are the most applicable but are not being implemented. The majority of professionals responded that sustainable practices related to water use reduction and renewable energy sources are most applicable but are not currently being implemented. They also responded that sustainable practices related to bicycle facilities, green roofs, and rainwater harvesting are not applicable but are currently being implemented. The lack of training and limited awareness of the benefits of sustainable design and construction may be contributing to the lack of sustainable practices. As a whole, professionals in Kuwait appear to undervalue sustainable design and construction practices that promote environmental sustainability. This study provides a benchmark, indicating a lack of shared viewpoints and illustrates the need for more common objectives and the need for training among design and construction professionals in the region.

Purpose This study investigates the impact and role of digital twin technology in building automation (DTBA) from a sustainability viewpoint. It aims to enhance the understanding of how DTBA can boost efficiency, optimize quality and support sustainable practices in contemporary construction. By exploring the integration of DTBA with sustainable practices, the study seeks to demonstrate how DT can revolutionize building management and operations, leading to significant improvements in resource efficiency, environmental impact and overall operational excellence. Design/methodology/approach This research employs a bibliographic analysis and systematic review of 176 publications from the past five years (January 1, 2019 to December 31, 2023), focusing on the application and development of DTBA. The study methodically analyzes current trends, identifies research gaps and suggests future directions by synthesizing data from various studies, offering a comprehensive overview of the current state of DTBA research. The approach combines quantitative and qualitative analyses to provide robust insights into the advancements and challenges in the field. Findings The review identifies key development areas in DTBA, such as energy and environmental management, resource utilization within a circular economy and technology integration and interoperability. It highlights the necessity for further research to maximize DTBA’s potential in sustainable building automation. The findings suggest that while significant progress has been made, there is a critical need for innovations in data interoperability, predictive analytics and the integration of renewable energy sources to fully realize the benefits of DTBA in enhancing building sustainability. Originality/value This paper provides a thorough review of DTBA from a sustainability perspective, offering valuable insights into its current applications and future development potential. It serves as a crucial resource for researchers and practitioners looking to advance sustainable practices in the construction sector using DT technology. By bridging the gap between theoretical research and practical applications, the paper underscores the transformative potential of DTBA in driving sustainable development and provides a roadmap for future research and innovation in the field.

Airport sustainable construction practices are becoming more popular and a necessity in every construction project in the United States (US) and around the world. Sustainability is no longer just a trend but a good engineering practice. The Fort Lauderdale Executive Airport (FXE), as well as most airports in the US, has been applying sustainable design and construction practices to all their airport projects, airside and landside. FXE serves over 160,000 aircraft operations per year, one of the busiest General Aviation airports in the United States and the 61st busiest airport overall. Over 700 aircraft, including 115 jets and 37 helicopters, make FXE their year-round home. Recently, FXE completed the construction of an Aviation Service and Equipment Facility that obtained the LEED (Leadership in Energy and Environmental Design) Gold Certification from the US Green Building Council (USGBC). This paper will present the current sustainable practices been implemented in the new construction of airport facilities at FXE as well as other airports around the US including buildings and airfield pavement rehabilitation projects.

The use of building information modeling (BIM) has provided a means of increasing total project quality, providing accurate quantity take-offs, and improving scheduling, consequently diminishing total project contingencies and costs. Although BIM is a recent development, a lot of research has been conducted in order to further enhance the capabilities of BIM in design and construction. However, there has been very little research done so far on the effect that BIM has on sustainable construction practices. Hence, the goal of this research is to investigate the perceptions of the use of BIM for sustainable design and construction among designers and constructors. A survey was developed and administered through the Internet to determine the existing trends of BIM application in general as well as its use as a tool in sustainable design and construction. The survey results indicated that although the majority of the respondents believed that sustainable design and construction practices were of impor...

The energy‐intensive residential sector critically requires sustainable and highly efficient thermal insulation solutions. Due to the increasing demand for complex‐shaped parts, it remains challenging to give them insulating properties. Indeed, traditional processing methods for foam production offer limited control over the internal architecture, a key factor in performance. This paper aims to fill that gap by using Material Extrusion Additive Manufacturing (MEAM) as a new technique to produce tailored atactic Polystyrene components, leveraging additive manufacturing's ability to create complex geometries and control the internal structure (lattice)—capabilities that are usually restricted by traditional methods. Polystyrene is a favored material due to its lower thermal conductivity compared to other polymeric materials; however, conventional manufacturing processes, such as extrusion foaming or foam injection molding, are limited to standardized geometries and lack precise control over the internal cellular structure, a critical factor in determining thermal insulating capabilities. The MEAM process was optimized, revealing that a bed temperature above the glass transition temperature (T g ) is crucial for interlayer adhesion, while moderate printing speeds (e.g., 2200 mm/min) yielded the best mechanical performance. Thermal conductivity was found not to be linearly dependent on the infill density, showing a minimum of 0.03 W/(mK) at 25% infill density for the octahedral structure. Numerical simulations, validated against experimental heat flux data, confirmed the significance of natural convection within the air‐occluded cells, supported by high Jeffreys’ numbers (∼10 5 ). The closed‐cell structure obtained by MEAM positively contributes to thermal insulation by reducing the effects of natural convection within the cells. This work established MEAM as a promising pathway for fabricating structurally optimized insulators with performance that can rival or be tailored beyond traditional foams.

Polycarbonate/antibacterial blend nanocomposites in material extrusion 3D printing: Thermomechanical response, rheology, and biocidal metrics

Multi-parameter optimization of 3D-printed polyphenylene sulfide (PPS) for enhanced mechanical performance

Current research in sustainable development of the built environment acknowledge the role of building environmental sustainability assessment methods as market changers for sustainable buildings’ design and construction. While most of the existing studies are focused either on developing and comparing assessment methods, or on assessment methods’ performance outcomes, this research addresses how assessment methods are adopted in practice. To address this, a pilot study was designed with desktop study of literature and regulation documents, as well as 7 guided in-depth interviews with 8 professionals engaged with assessment methods in the UAE. While, the spread of sustainable design and construction practices is motivated by mandating the assessment methods for all projects, but, with various rating requirements for government and private development projects, the analysis has revealed the continuous development of communication channels for the spread of sustainable design and construction practices between the regulative bodies with: (a) clients through raising awareness activities, (b) projects professionals through training and technical support, and (c) suppliers of sustainable systems and products through quality assurance and certification procedures. Finally, the paper discusses these findings and outlines possible impact on theory, policy and practice.

Do extrusion temperature, printing speed, and layer time affect mechanical performance of interlayer bonds in material extrusion additive manufacturing (MEAM)? The question is one of the main challenges in 3D printing of polymers. This article aims to analyze the independent effect of printing parameters on interlayer bonding in MEAM. In previous research, printing parameters were unavoidably interrelated, such as printing speed and layer cooling time. Here, original specimen designs allow the effects to be studied independently for the first time to provide new understanding of the effects of a wide range of thermal factors on mechanical properties of 3D-printed polylactide. The experimental approach used direct GCode design to manufacture specially designed single-filament-thick specimens for tensile testing to measure mechanical and thermal properties normal to the interface between layers. In total, five different extrusion temperatures (a range of 60°C), five different printing speeds (a 16-fold change in the magnitude) and four different layer times (an 8-fold change) were independently studied. The results demonstrate interlayer bond strength to be equivalent to that of the bulk material within experimental scatter. This study provides strong evidence about the crucial role of microscale geometry for apparent interlayer bond strength relative to the role of thermal factors. By designing specimens specifically for the MEAM process, this study clearly demonstrates that bulk-material strength can be achieved for interlayer bonds in MEAM even when printing parameters change severalfold. Widespread industrial and academic efforts to improve interlayer bonding should be refocused to study extrusion geometry-the primary cause of anisotropy in MEAM.

ABSTRACTThree‐point bending tests were performed on notched specimens extracted from cuboids of 316L stainless steel produced via material extrusion additive manufacturing. The cuboids were printed vertically and horizontally on the printing platform to account for the building orientation effect on the mechanical performance. For each orientation, three notch sizes were considered. Overall, the specimens printed with building direction parallel to the loading direction outperformed the others. A significant notch size effect was observed in these specimens since the sharpest notch provoked a decrease in the peak load reached by the specimens in comparison with larger notches. On the contrary, this effect was less relevant among the other specimens, which presented a conspicuous amount of residual porosity that contributed to the premature failure. Further investigations were carried out to correlate the building orientation to the density of the parts and, ultimately, to the investigated mechanical properties. The ASED and TCD criteria were also applied to assess their accuracy in the failure prediction of the tested specimens.

PurposeMechanical anisotropy associated with material extrusion additive manufacturing (AM) complicates the design of complex structures. This study aims to focus on investigating the effects of design choices offered by material extrusion AM – namely, the choice of infill pattern – on the structural performance and optimality of a given optimized topology. Elucidation of these effects provides evidence that using design tools that incorporate anisotropic behavior is necessary for designing truly optimal structures for manufacturing via AM.Design/methodology/approachA benchmark topology optimization (TO) problem was solved for compliance minimization of a thick beam in three-point bending and the resulting geometry was printed using fused filament fabrication. The optimized geometry was printed using a variety of infill patterns and the strength, stiffness and failure behavior were analyzed and compared. The bending tests were accompanied by corresponding elastic finite element analyzes (FEA) in ABAQUS. The FEA used the material properties obtained during tensile and shear testing to define orthotropic composite plies and simulate individual printed layers in the physical specimens.FindingsExperiments showed that stiffness varied by as much as 22% and failure load varied by as much as 426% between structures printed with different infill patterns. The observed failure modes were also highly dependent on infill patterns with failure propagating along with printed interfaces for all infill patterns that were consistent between layers. Elastic FEA using orthotropic composite plies was found to accurately predict the stiffness of printed structures, but a simple maximum stress failure criterion was not sufficient to predict strength. Despite this, FE stress contours proved beneficial in identifying the locations of failure in printed structures.Originality/valueThis study quantifies the effects of infill patterns in printed structures using a classic TO geometry. The results presented to establish a benchmark that can be used to guide the development of emerging manufacturing-oriented TO protocols that incorporate directionally-dependent, process-specific material properties.