Search results

Because of the anisotropy of the process and the variability in the quality of printed parts, finite element analysis is not directly applicable to recycled materials manufactured using fused filament fabrication. The purpose of this study is to investigate the numerical-experimental mechanical behavior modeling of the recycled polymer, that is, recyclable polyethylene terephthalate (rPET), manufactured by a deposition FFF process under compressive stresses for new sustainable designs.

In all, 42 test specimens were manufactured and analyzed according to the ASTM D695-15 standards. Eight numerical analyzes were performed on a real design manufactured with rPET using Young's compression modulus from the experimental tests. Finally, eight additional experimental tests under uniaxial compression loads were performed on the real sustainable design for validating its mechanical behavior versus computational numerical tests.

As a result of the experimental tests, rPET behaves linearly until it reaches the elastic limit, along each manufacturing axis. The results of this study confirmed the design's structural safety by the load scenario and operating boundary conditions. Experimental and numerical results show a difference of 0.001–0.024 mm, allowing for the rPET to be configured as isotropic in numerical simulation software without having to modify its material modeling equations.

The results obtained are of great help to industry, designers and researchers because they validate the use of recycled rPET for the ecological production of real-sustainable products using MEX technology under compressive stress and its configuration for numerical simulations. Major design companies are now using recycled plastic materials in their high-end designs.

Validation results have been presented on test specimens and real items, comparing experimental material configuration values with numerical results. Specifically, to the best of the authors’ knowledge, no industrial or scientific work has been conducted with rPET subjected to uniaxial compression loads for characterizing experimentally and numerically the material using these results for validating a real case of a sustainable industrial product.

In this study, researchers applied blended learning program to investigate the success of a blended learning program on satisfaction of the psychological needs, and academic achievement of chemistry students of O-Levels, following curriculum prescribed by University of Cambridge.

Research pattern is quantitative aligned with the quasi-experimental and pre-post experimental design which aimed at examining the efficiency of a motivational strategies adopted with the use of blended learning program on psychological needs satisfaction (competence, autonomy, and relatedness) and achievement in chemistry O-Levels Syllabus, at the end of the research program.

Hypothesis testing represented that use of blended learning program has significant and positive impact on academic achievements through the mediation of autonomy. Results also revealed the substantial association of blended learning on other psychological needs (i.e., competence and relatedness); however, the competence and relatedness have no effect on academic achievements in this study. Thus, research concludes that providing an autonomous environment in substitution of the controlled environment promotes learning and produces positive outcomes.

Blended learning or use of Learning Management Systems is being commonly used mostly in the tertiary level of studies; however, blended learning with secondary classes especially in the field of chemistry is yet not studied in detail. Similarly, the usefulness of the motivational strategies to learn chemistry is observed with university-level students, but very rare data about encouraging students at the secondary level have been gathered. Therefore, the researcher designed this blended learning program to enhance students’ motivation towards achievements in secondary chemistry.

The “chiralisation” of Euclidean polygonal tessellations is a novel, recent method which has been used to design new auxetic metamaterials with complex topologies and improved geometric versatility over traditional chiral honeycombs. This paper aims to design and manufacture chiral honeycombs representative of four distinct classes of 2D Euclidean tessellations with hexagonal rotational symmetry using fused-deposition additive manufacturing and experimentally analysed the mechanical properties and failure modes of these metamaterials.

Finite Element simulations were also used to study the high-strain compressive performance of these systems under both periodic boundary conditions and realistic, finite conditions. Experimental uniaxial compressive loading tests were applied to additively manufactured prototypes and digital image correlation was used to measure the Poisson’s ratio and analyse the deformation behaviour of these systems.

The results obtained demonstrate that these systems have the ability to exhibit a wide range of Poisson’s ratios (positive, quasi-zero and negative values) and stiffnesses as well as unusual failure modes characterised by a sequential layer-by-layer collapse of specific, non-adjacent ligaments. These findings provide useful insights on the mechanical properties and deformation behaviours of this new class of metamaterials and indicate that these chiral honeycombs could potentially possess anomalous characteristics which are not commonly found in traditional chiral metamaterials based on regular monohedral tilings.

To the best of the authors’ knowledge, the authors have analysed for the first time the high strain behaviour and failure modes of chiral metamaterials based on Euclidean multi-polygonal tessellations.

Employee engagement has been directly linked to organizational outcomes, and at present, improving employee engagement has increasingly been a main focus for organizations. However, studies evaluating the impact of storytelling interventions on increasing the level of employee engagement are limited. Storytelling is one of the intervention methods that can provide cognitive stimulus to employees, which in turn could change their attitudes toward work including employee engagement. The purpose of this study is to determine the effectiveness of storytelling as an intervention tool for increasing employee engagement in one of the state-owned enterprises (SOEs) in West Java, Indonesia.

This study uses a quantitative method. Employees from a West Java branch of large SOEs were randomly assigned into experimental and control groups. The research design used a pretest and a post-test with an expressive writing method to identify the extent of employee engagement by comparing participant groups and measuring the increase of employee engagement as a result of the storytelling intervention. The experimental group participated in three storytelling sessions that had been set up by panels of experts, while the control group was not given any treatment. The expressive writing analysis was conducted using software that has been developed and tested for validity and reliability. Furthermore, statistical analysis was used to test the results of expressive writing scoring to determine the impact of storytelling interventions.

Direct storytelling is proven to be one of the most effective methods of increasing employee engagement in one of the SOEs in the West Java region. The results of this study showed that there were differences between the experiment and control groups after experiencing a direct storytelling intervention where there was a significant increase in the dimensions of employee engagement. Participants in experimental group had higher scores than participants in control group in most of the employee engagement dimensions. Additionally, expressive writing methods are also proven to be able to provide a stimulus for employees in expressing thoughts, perceptions and motivations for employee engagement in the company.

As direct storytelling has not been frequently used, especially to improve employee engagement, more studies should be conducted in various settings, with different measurement tools, and in a more controlled environment to confirm the effects of the intervention.

This paper provides insight into how companies can use direct storytelling to improve the dimensions of employee engagement. Additionally, this research can also be used as a reference by companies in Indonesia, especially SOEs, for applying the same method in an effort to improve work-related attitudes, such as employee satisfaction and organizational commitment.

This study raises social implications in which employees enthusiasm increases in improving personal relationships between employees and storytellers, who are middle or upper management employees. In addition, employees also more appreciate their struggles when starting their careers, so they care more about increasing their role and involvement in the company.

This paper provides resources and information for companies and organizations to improve employee engagement through the implementation of direct storytelling. The focus of this paper is to gain information on the role of direct storytelling in improving employee engagement within a company or organization.

Entrepreneurship-based learning (EBL) is one of the student-center learningmethods that can answer learning challenges in the era of industrial revolution 4.0. EBL is expected to improve students’ competencies and make students more adaptable to the changes in the world of work in the future. The paper aims to discuss this issue.

This study uses quasi-experiments and divides classes into project class and control class. The project consists of making business proposals, conducting business, liquidating the partnership, and recording business transaction using the Xero platform. The Wilcoxon Signed Ranks Test, Mann–Whitney Test and independent t-test were carried out to test whether there are differences of cognitive abilities and entrepreneurial (general, social and functional) competencies between the project class and control class.

The results of the study shows there are differences of understanding of partnership accounting and the achievement of social and functional entrepreneurial competencies between the project class and control class.

This study implies in using EBL to improve entrepreneurial skills for students beyond cognitive abilities.

The novelty of this research is the implementation of EBL in partnership accounting topics.

The purpose of the research was to, first, investigate if the use of maps as instructional resources will boost scholarly performance and, second, examine if gender can moderate the effect of map usage on scholarly performance.

The study was a quasi-experimental pre-test and post-test. A sample of 260 JSS II Students from 8 schools were selected through the purposive sampling technique. A Social Studies Scholarly Performance Test (SSSPT) with a reliability index of 0.79 was the instrument for data collection. The students were assigned into two groups: control and experimental. Both groups were pre-tested taught for a timeline of six weeks and thereafter post-tested.

The study reported a significant increase in the scholarly performance of students taught with maps; a significant difference occurred in the scholarly performance of both groups and gender did not moderate the effect of maps.

The social studies teachers used for the study did not have previous knowledge or map skills; this could have affected the outcome. Secondly, the treatment took place for just six weeks, and the time allotted for social studies in the school timetable was used. This may not have given the students enough time to master map interpretation.

A major implication of the study is that results will show that maps can promote the scholarly performance of students in social studies. Secondly, the fact that gender did not moderate the effect of maps suggests that maps are gender-friendly.

The results of the study, if implemented, would make social studies teachers to become inventive and resourceful in the use of maps as instructional resources for junior secondary students' scholarly performance in social studies without taking gender into consideration.

This study is a product of the researcher’s doctoral thesis; therefore, it is original and has value. The results are the product of a painstaking study carried out by the author for a period of three years on the effect of instructional resources on social studies students’ scholarly performance. Maps were one of the instructional resources studied for the award of a Ph.D. degree.

Auxiliary power system is an indispensable part of the train; the auxiliary systems of both electric locomotives and EMUs mainly are powered by one of the two ways, which are either from auxiliary windings of traction transformers or from DC-link voltage of traction converters. Powered by DC-link voltage of traction converters, the auxiliary systems were maintained of uninterruptable power supply with energy from electric braking. Meanwhile, powered by traction transformers, the auxiliary systems were always out of power while passing the neutral section of power supply grid and control system is powered by battery at this time.

Uninterrupted power supply of auxiliary power system powered by auxiliary winding of traction transformer was studied. Failure reasons why previous solutions cannot be realized are analyzed. An uninterruptable power supply scheme for the auxiliary systems powered by auxiliary windings of traction transformers is proposed in this paper. The validity of the proposed scheme is verified by simulation and experimental results and on-site operation of an upgraded HXD3C type locomotive. This scheme is attractive for upgrading practical locomotives with the auxiliary systems powered by auxiliary windings of traction transformers.

This scheme regenerates braking power supplied to auxiliary windings of traction transformers while a locomotive runs in the neutral section of the power supply grid. Control objectives of uninterrupted power supply technology are proposed, which are no overvoltage, no overcurrent and uninterrupted power supply.

The control strategies of the scheme ensure both overvoltage free and inrush current free when a locomotive enters or leaves the neutral section. Furthermore, this scheme is cost low by employing updated control strategy of software and add both the two current sensors and two connection wires of hardware.

This paper aims to elaborate the method and algorithm for the analysis of the influence of temperature on back electromotive force (BEMF) waveforms in a line start permanent magnet synchronous motor (LSPMSM).

The paper presents a finite element analysis of temperature influence on BEMF and back electromotive coefficient in a LSPMSM. In this paper, a two-dimensional field model of coupled electromagnetic and thermal phenomena in the LSPMSM was presented. The influence of temperature on magnetic properties of the permanent magnets as well as on electric and thermal properties of the materials has been taken into account. Simulation results have been compared to measurements. The selected results have been presented and discussed.

The simulations results are compared with measurements to confirm the adequacy of this approach to the analysis of coupled electromagnetic-thermal problems.

The paper offers appropriate author’s software for the transient and steady-state analysis of coupled electromagnetic and thermal problems in LSPMS motor.

The present study aims to synthesize and conceptualize, through a systematic literature review (SLR), the current state of gamification knowledge in the tourism and hospitality (T&H) sector, providing a roadmap for future research recommendations for service research and practice.

The research is based on a systematic literature review and adopts a systematic quantitative approach to summarize existing evidence on gamification usage in the T&H sector, focusing on relevant service literature on gamification. The authors analyze 36 papers published between 2011 and 2019.

The authors synthesize existing knowledge into five themes describing gamification's role in T&H (Edutainment, Sustainable behavior, Engagement factors, Service provider-generated content and User-generated reviews). Then, a cross-analysis of the five themes reveals the pivotal elements (affordances, behavioral and psychological outcomes, and benefits) generated by gamification mechanics in T&H, simultaneously highlighting potential implications and relevant insights for service literature. The review identifies critical issues affecting gamification research and provides a future research agenda, considering opportunities for T&H and service research.

The study provides the first SLR investigating gamification in T&H. The findings present potential implications and relevant insights for T&H contributing to the construction of a more holistic understanding of gamification adoption in service research.

The purpose of this study concerns numerical studies and experimental validation of the mechanical behavior of hybrid specimens. These kinds of composite specimens are made up of thin carbon and glass substrates on which some Macro Fiber Composite^® (MFC) piezoelectric patches are glued. A proper design and manufacturing of the hybrid specimens as well as testing activities have been performed. The research activity has been carried out under the FutureWings project, funded by the European Commission within the 7th Framework.

The paper describes the basic assumptions made to define specimen geometries and to carry out experimental tests. Finite element (FE) results and experimental data (laser technique measurements) have been compared: it shows very good agreement for the displacements’ distribution along the specimens.

Within the objectives of the project, the study of passive and active deformation characteristics of the hybrid composite material has provided reference technical data and has allowed for the correct adaptation of the FE models. More in particular, using the hybrid specimens, both the bending deformations and the torsion deformations have been studied.

The deformation capability of the hybrid specimens will be used in the development of prototypical three-dimensional structures, that, through the electrical control of the MFC patches, will be able to change the curvature of their cross section or will be able to change the angle of torsion along their longitudinal axis.

The design of nonstandard specimens and the tests executed represent a novelty in the field of structures using piezoelectric actuators. The numerical and experimental data of the present research constitute a small step forward in the field of smart materials technology.