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The aim of this experimental investigation is to assess the antibacterial resistance of a biodegradable Polylactic acid (PLA) based composite material enriched with non-copper metallic particles, notably Stainless Steel, and Aluminum as alternatives to copper. The composite materials were processed using additive manufacturing technology using commercial fused deposition modeling printers to produce samples for antibacterial testing. The antibacterial materials were assessed according to international standards to evaluate the antibacterial efficacy at different time intervals. It has been disclosed that the biodegradable PLA composite enhanced with Stainless Steel or Aluminum demonstrated an excellent resistance against distinct kinds of bacteria through the observed significant reduction in the bacteria levels.

Construction projects are often challenged by tight budgets and limited resources. Contractors are looking for ways to become competitive by using methods and materials that are sustainable and cost-effective. Using sustainable 3D printing to produce cost-effective construction elements is becoming a feasible option to make contractors more competitive locally and globally. Along this line, contractors are attempting to improve production skills to satisfy certain specifications and standards while keeping costs within competitive ranges. The aim of this research is to investigate the production process capability of 3D printers using fused deposition modelling (FDM) to produce 3D-printed sustainable parts made from plastic waste for the use in the construction of buildings with different infill structures and internal designs. The production capabilities and requirements of FDM printers were first examined and possible applications in construction are then presented. The outcome of this study indicates that 3D-printers can be used to produce parts made from plastic waste using FDM printers. These parts are sustainable and less expensive as compared to some traditional non-load bearing construction elements such as lightweight concrete hollow blocks and lightweight concrete bricks since they are less expensive and have higher compressive strength. However, it is not feasible to use 3D printed material from plastic waste as an alternative for gypsum board drywalls since it is more expensive; however, it might be considered as an alternative since it provides a higher compressive strength.

Novel strategies and materials have gained the attention of researchers due to the current pandemic, the global market high competition, and the resistance of pathogens against conventional materials. There is a dire need to develop cost-effective, environmentally friendly, and biodegradable materials to fight against bacteria using novel approaches and composites. Fused filament fabrication (FFF), also known as fused deposition modeling (FDM), is the most effective and novel fabrication method to develop these composites due to its various advantages. Compared to metallic particles alone, composites of different metallic particles have shown excellent antimicrobial properties against common Gram-positive and Gram-negative bacteria. This study investigates the antimicrobial properties of two sets of hybrid composite materials, i.e., Cu-PLA-SS and Cu-PLA-Al, are made using copper-enriched polylactide composite, one-time printed side by-side with stainless steel/PLA composite, and second-time with aluminum/PLA composite respectively. These materials have 90 wt.% of copper, 85 wt.% of SS 17-4, 65 wt.% of Al with a density of 4.7 g/cc, 3.0 g/cc, and 1.54 g/cc, respectively, and were fabricated side by side using the fused filament fabrication (FFF) printing technique. The prepared materials were tested against Gram-positive and Gram-negative bacteria such as Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), Pseudomonas aeruginosa (P. aeruginosa), Salmonella Poona (S. Poona), and Enterococci during different time intervals (5 min, 10 min, 20 min, 1 h, 8 h, and 24 h). The results revealed that both samples showed excellent antimicrobial efficiency, and 99% reduction was observed after 10 min. Hence, three-dimensional (3D) printed polymeric composites enriched with metallic particles can be utilized for biomedical, food packaging, and tissue engineering applications. These composite materials can also provide sustainable solutions in public places and hospitals where the chances of touching surfaces are higher.

This paper aims to investigate experimentally and using finite element analysis the performance of using three-dimensional printing technology to produce a composite sandwich panel that is made of the high-flexible core as well as with high stiffness upper and lower surfaces made of a glass fiber reinforced composite filament. There are many advantages of using sandwich structures in many applications, especially the aerospace field, where the high stiffness to strength and the lightweight is the most preferred in such applications. The conventional manufacturing methods that are used to produce sandwich panels are limited to particular core geometry, whereas manufacturing a composite core is not possible by these traditional production methods. So by using additive manufacturing technology, it becomes more applicable to design a combination of different geometries and materials to achieve properties that have never been made before, especially combining flexibility and high energy absorption keeping high strength to failure. A central deflection to a length of 0.26 is observed within the elastic zone, a remarkable ratio in beams that reflects the three-dimensional printed sandwich beams’ capability with a highly flexible core to absorb energy that would open doors for many industrial applications that is attributed to the lowest flexural rigidity (167E-3Pa · m4) of the sandwich by using the TriHex infill pattern. In contrast, the Gyroid infill structure could afford the highest central load (0.264 kN). At the peak load applied on the sandwich beam, a maximum error of 5.4% is estimated by finite element analysis lower than the experimental values.

Purpose This paper aims to use quick response (QR) code along with online videos to teach one of the college foundation courses in an international institution to enhance the grasp of the students and to boost the students’ learning outcomes. Design/methodology/approach The study discussed and elaborated the findings that mainly focused on the usage of the online resources to teach Engineering Economy course. Besides, the authors analyzed how the gender may have different feedback for the student. Findings The study emphasized on the expectations of the students to use videos in the learning experience that preferred to be developed by course educator and to be published on the university platform, like blackboard or faculty website, that conforms university transformation vision undergoing nowadays. It is recommended to have a successful learning experience; it is the educator's responsibility to improve the personal digitization skills that would be used in the e-learning implementations, that will be used for the educational technology, which requires the use of creative media production mobile applications. Practical implications The education field has witnessed significant development over the past years in terms of using digital technologies as pedagogical tools to enhance the students’ learning experience especially the internet, where the traditional trends become outdated to be used in the classrooms. One of the main players in this field is videos that are considered as the main influencer to this educational change, where it has been demonstrated to and boost the quality of the learning experience. Originality/value In this study, students participated to explore the usefulness of using online learning through using videos blended with QR code to enhance the students’ performance in understanding one of the undergraduate foundation courses in the college of engineering, namely, engineering economy. A survey was distributed to students after the core material of the course was covered. The collected responses were then studied and analyzed.

E-learning offers tremendous benefits to teachers and students as it enhances the teaching and learning experience. Despite the adoption of e-learning in many educational institutions worldwide, de...

Due to the prevailing existence of the COVID-19 pandemic, novel and practical strategies to combat pathogens are on the rise worldwide. It is estimated that, globally, around 10% of hospital patients will acquire at least one healthcare-associated infection. One of the novel strategies that has been developed is incorporating metallic particles into polymeric materials that neutralize infectious agents. Considering the broad-spectrum antimicrobial potency of some materials, the incorporation of metallic particles into the intended hybrid composite material could inherently add significant value to the final product. Therefore, this research aimed to investigate an antimicrobial polymeric PLA-based composite material enhanced with different microparticles (copper, aluminum, stainless steel, and bronze) for the antimicrobial properties of the hybrid composite. The prepared composite material samples produced with fused filament fabrication (FFF) 3D printing technology were tested for different time intervals to establish their antimicrobial activities. The results presented here depict that the sample prepared with 90% copper and 10% PLA showed the best antibacterial activity (99.5%) after just 20 min against different types of bacteria as compared to the other samples. The metallic-enriched PLA-based antibacterial sheets were remarkably effective against Staphylococcus aureus and Escherichia coli; therefore, they can be a good candidate for future biomedical, food packaging, tissue engineering, prosthetic material, textile industry, and other science and technology applications. Thus, antimicrobial sheets made from PLA mixed with metallic particles offer sustainable solutions for a wide range of applications where touching surfaces is a big concern.

This experimental study aims to explore the failure behavior of a pre- and post-cracked polymeric 3D printed components subjected to tensile mode. A set of through-thickness pre-cracked specimens of different cracks patterns and geometry was designed and implemented in the 3D printed parts. The specimens are then subjected to a tensile test mode. Besides, analogous intact samples were produced by 3D printing technology where the through-thickness post-cracks were created using laser cutting process of a geometry with cracks similar to those of the pre-cracked specimens. It has been observed that the pre-cracked samples initially introduced, and 3D printed cracked specimens have more resistance to fracture mechanics failure due to crack-bridging caused by the 3D printing filament profile around the crack profile. On the other hand, the samples with post-cracks made by laser cutting demonstrated a significant drop in the fracture failure resistance due to the interruption of the 3D printed filaments of the intact specimens. In conclusion, this study revealed that pre-cracked 3D printed components did not show the actual failure and fracture mechanics behavior. This is because the cracks could be introduced in the components after the additive manufacturing process during the service life and that would damage the 3D printed filament path of the components and, hence, will cause high-stress concentration that leads to unpredicted and fast failure.

Major cities in most of the developing countries are becoming increasingly crowded. Conventional open-trench methods are expensive and lead to traffic disruption. The domestic government is looking at alternative approaches to install and rehabilitate aging underground utilities. The purpose of this study is to investigate the level of awareness and utilization of no-dig (i.e., trenchless technology) methods, the potential of their future growth, and their impact on social costs in a developing country. A survey was first conducted to investigate the use of trenchless technology methods in new construction and rehabilitation of infrastructure projects. The pertaining impact on social costs was then examined. Survey data were analyzed, and the potential of future growth of using trenchless technology methods was investigated. It has been found that “horizontal directional drilling” is the prevalent trenchless method used, while “robotic spot repair” is the least utilized one among all the methods used for new construction or rehabilitation of underground utilities. The results also revealed that using trenchless construction has a maximum impact on the “travel/traffic delay” type of social costs. The “horizontal directional drilling” method has the highest potential of future growth in new construction, while the “lining of pipe” was ranked first among rehabilitation methods. The data analysis results have also revealed that a critical social implication of using trenchless construction methods is their limited disruptions to the society when installing or rehabilitating underground utilities. Such social disruptions include road closures, traffic delays, and detours resulting in noise and loss of access to homes/businesses.

This paper presents the use of an interactive learning approach in the Engineering Ethics course. Intuitive learning is being implemented in traditional teaching methods, which will engage students in class activities, improve their self-learning skills, and promote active learning. Integrating interactive learning activities has been noted to improve students' learning, course attainment, and learning outcomes. This study is aimed to demonstrate the use of web-based applications (e.g., Quizlet and Kahoot!) to improve students' academic achievement and enhance their engagement in class.

It has been addressed that one of the factors that has a significant impact on the properties of the composite is the fiber/matrix interface that would increase the interfacial levels of the stresses which will reduce the overall composite stiffness and the fatigue lifetime eventually causing composite failure. Besides it has been concluded that interfacial stresses play a major role in the deterioration of the composite characteristics due to increase in the possibility of the debonding between fiber/matrix zone that will raise the interfacial levels of the stresses and lead to the failure at the end. Different methods have been adopted experimentally and theoretically to understand the mechanism of interfacial failure between fiber/matrix in the composite. In this chapter, we focus on the simulation and the mathematical model that has been developed and used to investigate the impact of the fiber/matrix role in the deterioration and the failure of the composite using micromechanics, finite element method, and other methods.

Construction projects are complex and involve thousands of details and complex interrelationships among several parties. In this multidisciplinary environment, claims are immanent and appear to cau...

Construction projects are often challenged by tight budgets and limited time and resources. Contractors are, therefore, looking for ways to become competitive by improving efficiency and using cost-effective materials. Using three-dimensional (3D) printing for shaping materials to produce cost-effective construction elements is becoming a feasible option to make contractors more competitive locally and globally. The process capabilities for 3D printers and related devices have been tightened in recent years with the booming of 3D printing industries and applications. Contractors are attempting to improve production skills to satisfy firm specifications and standards, while attempting to have costs within competitive ranges. The aim of this research is to investigate and test the production process capability (Cp) of 3D printers using fused deposition modeling (FDM) to manufacture 3D printed parts made from plastic waste for use in the construction of buildings with different infill structures and internal designs to reduce cost. This was accomplished by calculating the actual requirement capabilities of the 3D printers under consideration. The production capabilities and requirements of FDM printers are first examined to develop instructions and assumptions to assist in deciphering the characteristics of the 3D printers that will be used. Possible applications in construction are then presented. As an essential outcome of this study, it was noticed that the 3D printed parts made from plastic waste using FDM printers are less expensive than using traditional lightweight non-load bearing concrete hollow masonry blocks, hourdi slab hollow bocks, and concrete face bricks.

With the rapid growth in the manufacturing industry and increased urbanization, higher amounts of composite material waste are being produced, causing severe threats to the environment. These environmental concerns, coupled with the fact that undergraduate students typically have minimal experience in research, have initiated the need at the UAE University to promote research among undergraduate students, leading to the development of a summer undergraduate research program. In this study, a recycling methodology is presented to test lab-fabricated Carbon-Fiber-Reinforced Polymer (CFRP) for potential applications in industrial composite waste. The work was conducted by two groups of undergraduate students at the UAE University. The methodology involved the chemical dissolution of the composite waste, followed by compression molding and adequate heat treatment for rapid curing of CFRP. Subsequently, the CFRP samples were divided into three groups based on their geometrical distinctions. The mechanical properties (i.e., modulus of elasticity and compressive strength) were determined through material testing, and the results were then compared with steel for prompt reference. The results revealed that the values of mechanical properties range from 2 to 4.3 GPa for the modulus of elasticity and from 203.7 to 301.5 MPa for the compressive strength. These values are considered competitive and optimal, and as such, carbon fiber waste can be used as an alternate material for various structural applications. The inconsistencies in the values are due to discrepancies in the procedure as a result of the lack of specialized equipment for handling CFRP waste material. The study concluded that the properties of CFRP composite prepreg scrap tend to be reusable instead of disposable. Despite the meager experimental discrepancies, test values and mechanical properties indicate that CFRP composite can be successfully used as a material for nonstructural applications.

Conventional methods of teaching structural engineering topics focus on face-to-face delivery of course materials. This study shows that using video-based e-learning in delivering an undergraduate Structural Steel Design course satisfactorily achieved most of the course learning outcomes. Video-based e-learning with animations and simulations gives students a profound understanding of the course intricate design materials. To gauge the effectiveness of video-based e-learning of the course, an online evaluation was conducted by sixty-eight undergraduate students at the United Arab Emirates University using Blackboard. The evaluation consisted of an online survey that was accessible by students who took the structural steel design course in the academic year 2019 using instructional videos provided to them as Quick Response (QR)-codes. The structural steel design course has six learning outcomes (CLOs), and the performance of students in the six CLOs was compared with that of students who took the same course in the academic year 2018 using the traditional face-to-face lecturing method. The survey data was statistically analyzed, and the results revealed that students’ performance improved, and most of the CLOs were attained. Video-based e-learning with animations resulted in better learning outcomes compared to face-to-face lecturing. Accessing the course instruction videos anytime and anywhere is one of the remarkable benefits to the students studying through the e-learning approach.

This paper investigates the impact of corporate governance on the profitability of joint-stock insurance firms listed and unlisted in the ‘Damascus Securities Exchange’ in Syria during the period from 2013 to 2019. Research data was collected from the financial reports of the insurance firms and the reports of the ‘Syrian Insurance Supervisory Commission’ and the ‘Syrian Commission of Financial Markets and Securities’. A model was then proposed for corporate governance of insurance firms. The proposed model considers eight independent variables (board size, independence of board members, non-executive board members, solvency, ownership, firm size, firm age, and joint-stock) and two dependent variables (return on equity and return on shares). Multi regression analysis for the ‘Balanced Panel Data’ is used to analyze the relationship between the governance of insurance firms and their profitability. The analysis of the results revealed that some independent variables (such as firm size, ownership, and none-executive members) have a significant positive impact on the return on equity while the ‘firm size’ and ‘ownership’ independent variables have a significant positive impact on the return on shares. The ‘solvency’ variable has a significant negative impact on the return on equity and return on shares. On the other hand, the ‘firm age’ variable has a significant negative impact on the return on equity while the ‘joint-stock’ variable is considered statistically significant with a positive impact on the return on shares. It was also observed that the ‘independence of board members’ variable has no impact on the dependent variables.

One of the main challenges that the educator faces in integrating 3D printing technology in a traditional engineering course in the capability of introducing and merging the 3d printing technology at the right educational material. The paper aims to present the challenges and the achievements of integrating 3D printing technology in teaching design and manufacturing courses in the mechanical engineering department to enhance the students’ skills and engagement with the course material. One of the course experiments was nominated to introduce the 3D printing technology, where the students were asked to use the systematic design method as well as design matrix procedure to explore different options to come up with a solution to hold a mechanical component for quality control task. Besides, the students had to design an engineering measurement procedure to achieve the assigned mission of the experiment, where the mechanical part was described to present the main dimensions needed for the measurement sequence. Different groups submitted innovative ideas that were evaluated initially and discussed individually before submitting the final design and the holder prototype. The students presented a functional 3D printed prototype with a full report that clarifies the engineering procedure adopted to achieve the goal of the experiment. The innovation in the addressed solution revealed the importance of 3D printing technology to enhance the students’ skill and engagement with the course material and help them to encounter challenges to come up with creative engineering solutions.

Current environmental concerns have led to a search of more environmentally friendly manufacturing methods; thus, natural fibers have gained attention in the 3D printing industry to be used as bio-filters along with thermoplastics. The utilization of natural fibers is very convenient as they are easily available, cost-effective, eco-friendly, and biodegradable. Using natural fibers rather than synthetic fibers in the production of the 3D printing filaments will reduce gas emissions associated with the production of the synthetic fibers that would add to the current pollution problem. As a matter of fact, natural fibers have a reinforcing effect on plastics. This review analyzes how the properties of the different polymers vary when natural fibers processed to produce filaments for 3D Printing are added. The results of using natural fibers for 3D Printing are presented in this study and appeared to be satisfactory, while a few studies have reported some issues.

PurposeDespite the popularity of existing course management systems, they do not consider the management of course material changes, particularly courses that require more than one instructor. The main purpose of this study is to instantly communicate course material changes to all instructors teaching the same course and to communicate approved changes to students registered on the course.Design/methodology/approachThe fundamental hypothesis tested was whether the developed system effectively communicates changes in a timely manner. The level of students' acceptance to this new system was also tested. A dynamic course material change‐management system was developed using visual basic programming language and an Access database. The system was applied to a hypothetical case study and to a currently running undergraduate civil engineering course.FindingsResults indicated that changes made to a course material were instantly communicated to all instructors teaching the same course. It also indicated that approved changes were instantly communicated to affected students. As a result, students were satisfied with the instant notifications they receive whenever a change takes place.Research limitations/implicationsThe proposed system does not include a methodology for online tests, course grades, and course assessment. The system needs to be integrated with these important features. Developments pertaining to integrating the system with these features will be considered for future investigation.Originality/valueThe novel aspect of the developed system is the effective management of challenges made to course material and communicating these changes to instructors and students in a timely manner. The system can benefit any institution at different educational levels.

In an effort to improve productivity and optimize resource use, the activity-on-arrow (AOA) approach is used in this paper to model and simulate real-world complex construction operations. First, simulation models for two construction operations of a large-size real-world international project were developed. Several experiments on these models were then conducted using different resource combinations to arrive at the best combination that improves productivity and reduces the operational cost. The developed models were used to experiment with different resource alternatives and overtime options for a single project and repetitive projects in order to arrive at the best alternatives that provide the least total direct cost or the shortest completion time for the two operations. The potential of using this approach for resource optimization of large infrastructure networks was then investigated and, finally, possible future extensions to the present study were discussed.

The development of trenchless methods has gained impetus in the construction industry in United Arab Emirates due to increasing amounts of investment in underground infrastructures that are new, deteriorating, or under capacity. This paper presents the results of a questionnaire survey of trenchless construction methods used by municipalities and contractors in United Arab Emirates. The survey provides an indication of current and expected future trends in the application of trenchless construction technologies including types of technologies employed and percentage of projects that employed trenchless technologies. The survey results indicate that trenchless technology is gaining increasing popularity among contractors and municipalities across United Arab Emirates. The survey results also indicate that trenchless technology is gaining increasing popularity among municipal engineers across UAE. The survey revealed current, and by extrapolation likely future growth, in utilizing trenchless construction methods and the average expenditures of municipalities in UAE for new construction and for rehabilitation.

Construction safety education for engineering students may involve two main aspects: construction site safety and design for construction safety (DfCS). Progress has been made in the developed countries to incorporate both aspects in the engineering curriculum. However, the extent to which engineering students in the Middle East and North Africa (MENA) region receive construction safety education during their undergraduate study is not known. To assess this extent, two survey forms were designed and distributed to engineering practitioners and construction-related engineering programs in the MENA region. The practitioners’ survey was also utilized to assess the need for comprising construction safety education in the engineering curriculum. The study showed that about 70 % of the surveyed practitioner engineers did not receive construction safety knowledge during their university education. Of those who did, almost half received such knowledge during internship. Meanwhile, about 50 % of those who received some construction safety education ranked the received level as being “average.” Results also showed that the majority of the surveyed practitioners believe that there is a need for more construction safety education at the university level. In terms of inclusion in the engineering curriculum, surveyed practitioners ranked 15 suggested safety aspects as important to very important to be included in the undergraduate curriculum. Responses received from contacted engineering programs indicated that assigning an entire course to cover construction safety is not common in the MENA region. While the majority of construction safety coverage was shown to be either as an integral part of a core course or through the internship, only 40 % of the programs indicated inclusion of construction safety topics as integral parts of elective courses that are commonly offered once a year. A major observation was that construction safety is included in less than 15 % of the graduation project courses offered by the responding programs, indicating a possibly high deficiency in comprising DfCS in the curriculum. In addition, Occupational Safety and Health Administration (OSHA) standards and in-house developed materials were reported as the most common data sources for teaching construction safety. The study proposes enhancing the current level of construction safety education for engineering students in the MENA region by incorporating a core course in the curriculum and by integrating several suggested topics of DfCS in traditional design courses.