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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.

Tests of assumed mediation models are common in research in many disciplines, including managerial psychology, industrial and organizational psychology, organizational behavior, and organizational theory. Thus, the purpose of this paper is to detail experimental design options for conducting such tests in a manner that has the potential to yield results that have high levels of internal and construct validity.

The paper presents a logical analysis of strategies for testing mediation models so as to insure valid inferences about causal relations between variables.

The most appropriate strategy for testing assumed mediation models is research that uses randomized experimental designs.

Managers should base their actions on valid evidence about phenomena. More specifically, managerial actions should be predicated on research results that have high levels of internal, construct, and statistical conclusion validity. Thus, this paper encourages managers to base decisions about organizational policies and practices on well‐designed experimental research.

This paper addresses a number of points about issues involving internal and construct validity in tests of assumed causal models that have not been covered in previous work.

The purpose of this paper is to report a field-based quasi-experimental study designed to examine the effectiveness of a transformational leadership intervention in remediating poor performance. The intervention was conducted on elements of the organization that senior management perceived as being low performing.

A quasi-experimental pre-test post-design was employed to evaluate the effectiveness of the transformational leadership intervention. Pre-test data were collected four months prior to the intervention starting and the post-test data were collected eight months after the intervention had started. Follower perceptions of their leader's behavior and group cohesion, together with training outcome data were used to evaluate the effectiveness of the intervention.

Results revealed that from pre-test to post-test changes in perceptions of leadership, group cohesion, and training outcome indicated that the intervention had beneficial effects. These beneficial effects were evidenced in one of two ways: desirable behaviors increased in the experimental group from pre-test to post-test while they remained the same or were decreased in the control group; or desirable behaviors remained the same in the experimental group while they decreased in the control group.

The current study is the first to utilize a quasi-experimental organization wide design to examine the efficacy of a transformational leadership intervention. Furthermore, the current study provides evidence that transformational leadership can buffer negative environmental effects.

In this article, we survey experiments that are directly related to monetary policy and central banking. We argue that experiments can also be used as a tool for central bankers for bench testing policy measures or rules. We distinguish experiments that analyze the reasons for non-neutrality of monetary policy, experiments in which subjects play the role of central bankers, experiments that analyze the role of central bank communication and its implications, experiments on the optimal implementation of monetary policy, and experiments relevant for monetary policy responses to financial crises. Finally, we mention open issues and raise new avenues for future research.

We review the experimental evidence on risk aversion in controlled laboratory settings. We review the strengths and weaknesses of alternative elicitation procedures, the strengths and weaknesses of alternative estimation procedures, and finally the effect of controlling for risk attitudes on inferences in experiments.

Using a pre‐test‐post‐test control group experimental research design, this paper seeks to examine the effects of the 20‐week structure of intellect (SOI) training programme on the critical thinking skills of a group of participants in a manufacturing facility in Ireland as measured by both Watson‐Glaser critical thinking skills assessment (CTSA) and Raven’s standard progressive matrices (SPM). The results demonstrate no statistically significant difference in the experimental group pre‐ and post‐test scores on the Watson‐Glaser CTSA, but the results derived from the administration of Raven’s SPM were significant (p = 0.003). As expected, no statistically significant difference was found between the pre‐ and post‐test performance of the control group on either test. A number of possible reasons for the results are advanced.

The purpose of this study is to understand the functional properties of ball valve in a compressible flow and simulation of experimental data collection of ball valve, was completely simulated.

Equations are solved according to finite volume and simplified algorithms. By measuring the flow parameters, including pressure and temperature at different points in the simulation circuit, flow coefficients and localized drop in the valve were determined in different openness cases of test valve and compared with experimental results. Determining a graph for flow coefficient variations in terms of the percentage of openness of the valve is very effective on the flow control as well as on optimizing its cross-section.

In the supersonic flow, flow coefficients and local drops of the valve are dependent on several parameters, including fluid flow rate. Flow coefficient graphs at different angles of the test valve show that by increasing the valve opening angle, the flow coefficient increases so that it reaches from 1.72 m³/h at a 30° angle to 46.29 m³/h at a 80° angle. It should be noted that these values in the experimental test were obtained 1.53 m³/h and 49.68 m³/h, respectively, and the percentage difference of these values by simulation was obtained for the angle of 30 degrees 11.7% and for the angle of 80°, about 7% per hour at an angle of 80°. Also, the coefficients of localized loss at different angles of test valve show that by increasing the angle of opening of the valve, the amount of localized loss decreases, so that the average value of 1515.2 in the angle of 30° reaches 1.9 at an angle of 80°. The percentage difference of these values by simulation, for the angle of 30° and 3.5% for the angle of 80°, was about 11.1%.

Determining a graph for flow coefficient variations versus the percentage of openness of the valve is very effective on the flow control as well as on optimizing its cross-section. In the supersonic flow, flow coefficients and local drop coefficients of the valve are dependent on several parameters, including fluid flow rate.

Experimental economics has been treated with skepticism by some Austrian economists. We argue that experimental methods are consistent with strong versions of praxeology, and are therefore not methodologically problematic for Austrians. We further argue that experimental research methods have illustrated many uniquely Austrian themes and provide a fruitful method for future Austrian-inspired research.

The purpose of this research is present an experimental and numerical study of the mechanical properties of the acrylonitrile butadiene styrene (ABS) in the additive manufacturing (AM) by fused filament fabrication (FFF). The characterization and mechanical models obtained are used to predict the elastic behavior of a prosthetic foot and the failure of a prosthetic knee manufactured with FFF.

Tension tests were carried out and the elastic modulus, yield stress and tensile strength were evaluated for different material directions. The material elastic constants were determined and the influence of infill density in the mechanical strength was evaluated. Yield surfaces and failure criteria were generated from the tests. Failures over prosthetic elements in tridimensional stresses were analyzed; the cases were evaluated via finite element method.

The experimental results show that the material is transversely isotropic. The elasticity modulus, yield stress and ultimate tensile strength vary linearly with the infill density. The stresses and the failure criteria were computed and compared with the experimental tests with good agreement.

This research can be applied to predict failures and improve reliability in FFF or fused deposition modeling (FDM) products for applications in high-performance industries such as aerospace, automotive and medical.

This research aims to promote its widespread adoption in the industrial and medical sectors by increasing reliability in products manufactured with AM based on the failure criterion.

Most of the models studied apply to plane stress situations and standardized specimens of printed material. However, the models applied in this study can be used for functional parts and three-dimensional stress, with accuracy in the range of that obtained by other researchers. The researchers also proposed a method for the mechanical study of fragile materials fabricated by processes of FFF and FDM.

The purpose of this paper is to present the results of an experimental campaign conducted on a recently developed fire protection system (FPS), specifically designed for installation on continuous glass curtain walls systems typical of multi-story buildings.

The authors will first present the theoretical derivation of the relevant parameters to characterize and predict the fire evolution and probability of flashover, according to existing codes and standards. Then, the results of two full-scale tests will be presented in terms of temperature fields, thermal gradients and position of the neutral plane.

The experimental evidence shows how the proposed system is able to dramatically reduce internal temperatures in the rooms interested by the fire, also allowing for safer evacuation procedures by increasing the height of the neutral plane.

The novel window frame element comprises an automatic doubly convergent aperture system that induces ventilation in the compartment by increasing internal convection in the rooms subject to the fire. This allows for an efficient dispersion of hot gases and fumes and a drastic improvement in safety for both the occupants and firefighting operators. The theoretical results are then compared to the experimental evidence to evaluate the performance of the proposed ventilation system in the context of existing standards and design procedures.