Experimental and Numerical Study of a Synthetic Jet Ejector

A traditional synthetic jet ejector is a combination of synthetic jet and mixing tube or shroud in which flow from the surroundings is entrained through the space between the jet and shroud and discharged from the end of a mixing tube. An objective of the current research is to evaluate the accuracy of a previous simplified numerical model using results from an improved numerical model and an experimental synthetic jet ejector water flow facility. The improved model gives a better representation of the primary jet velocity profile by accurately modeling the piston motion using the dynamic mesh option. Also, flow approaching the secondary inlet plane is considered in the new model by including the surrounding fluid in the solution domain. The model is used to show the shortcomings of certain assumptions made in the simplified model. Experimentally, the phase-averaged velocity field within the shroud is determined using Particle Image Velocimetry. It is shown that the improved numerical model gives a more accurate prediction of the variation of phase-averaged volume flow rate throughout the cycle and the cycle averaged values than the previous simplified model. Also, the numerical and phase-averaged experimental flow field patterns show some similarities however, certain details of the profiles are quite different. Extremely high turbulence level or intense mixing is detected near the exit of the synthetic jet. This is thought to be responsible for the shorter flow development noticed in the experiments compared with the numerical solution

A Case Study of Game-Based Learning in Interior Design Studios

The purpose of this paper is to understand perceptions of interior design students after using game-based learning (GBL) as an approach to address workload distribution, lack of clear assessment criteria, and deficiencies of the master-apprentice model during the process of solving several small-scale design problems along the course of a semester. A literature review of the instructional issues in design studios is presented along with an overview of the activity systems theory as an underpinning theoretical perspective. This research paper explains the research design behind the case study methodology used to perform data collection, analysis measures and organize coding schemes. Findings from the study conclude that GBL fits into the iterative and experimental nature of the design process, helps students focus on the design process through trial and error without a significant risk, changes the studio’s feedback structure, allows students to track their progress while having creative freedom. This paper provides empirical evidence supporting the existence of instructional issues in traditional design studios, provides considerations for using GBL to address these issues, and suggests directions for future research studies in fields of instructional technology, design pedagogy and higher education policy

On The Maintenance Modeling and Optimization of Repairable Systems: Two Different Scenarios

The use of mathematical modeling for the purpose of analyzing and optimizing the performance of repairable systems is widely studied in the literature. In this dissertation, we study two different scenarios on the maintenance modeling and optimization of repairable systems. First, we study the long-run availability of a traditional repairable system that is subjected to imperfect corrective maintenance. We use Kijima\u27s second virtual age model to describe the imperfect repair process. Because of the complexity of the underlying probability models, we use simulation modeling to estimate availability performance and meta-modeling to convert the reliability and maintainability parameters of the repairable system into an availability estimate without the simulation effort. As a last step, we add age-based, perfect preventive maintenance to our analysis. Second, we optimize a preventive maintenance policy for a two-component repairable system. When either component fails, instantaneous, minimal, and costly corrective maintenance is performed on the component. At equally-spaced, discrete points during the system\u27s useful life, the decision-maker has the option to perform instantaneous, imperfect, and costly preventive maintenance on one or both of the components, to instantaneously replace one or both of the components, or to do nothing. We use a Genetic Algorithm in an attempt to find a cost-optimal set of preventive maintenance and replacement decisions

A game-based design studio: An exploration of an interior design studio environment for implementing game-based learning

The design studio is an active, participatory, and experimental learning environment. Since the 19th century, the studio has been a place for learning through doing with a community of peers seeking knowledge, skills, and a space for unleashing creativity. The advancement in teaching and learning has shown to address a variety of instructional issues in a variety of fields using digital technology and innovative pedagogies. The design studio, despite its many affordances, has been criticized over the past decade for multiple reasons. This three-article dissertation focuses on using the game-based learning (GBL) pedagogy to address three instructional issues in interior design studios; time management and workload distribution, high dependency on the master-apprentice model, and ambiguity of assessment measures of student work. Each of the three articles stands as an independent piece of scholarly work. Yet all articles complement each other in multiple ways

Computer aided design and optimization of bi-layered tube hydroforming process

Tube hydroforming is one of the unconventional metal forming processes in which high fluid pressure and axial feed are used to deform a tube blank in the desired shape. However, production of bi-layered tubular components using this process has not been investigated in detail in spite of the large number of research studies conducted in this area. Bi-layered tubing can be useful in complex working environments as it offers dual properties that a single layer structure doesn’t have. Consequently, for wider implementation of this technology, a detailed investigation on bi-layered tube hydroforming is required. In this research, both single and bi-layered tube hydroforming processes were numerically modelled using the finite element method (ANSYS LS-DYNA). Experiments were conducted to check the numerical models validation. In addition, Response Surface Methodology (RSM) using the Design-Expert statistical software has been employed along with the finite element modelling to attain a detailed investigation of bi-layered tube hydroforming in the X-type and T-type dies. The process outputs were modelled as functions of both the geometrical factors (tube length, tube diameter, die corner radius, and thicknesses of both layers.) and the process parameters (internal pressure coordinates, axial feed, and coefficient of friction.). Furthermore, the desirability approach was used in conjunction with the RSM models to identify the optimal combinations of each the geometrical factors and process parameters that achieve different objectives simultaneously. In addition, a different optimization approach that applies the iterative optimization algorithm in the ANSYS software was implemented in the process optimization. The finite element models of single and bi-layered tube hydroforming processes were experimentally validated. A comparison of both processes was carried out under different loading paths. Also, response surface modelling of the bi-layered tube hydroforming process outputs was successfully achieved, and the main effects and interaction effects of the input parameters on the responses were discussed. Based on the RSM models, the process was optimized by finding the inputs levels at which the desired objectives are satisfied. Finally, a comparison of the RSM based optimization approach and the iterative optimization algorithm was performed based on the optimum results of each technique

The Effects Of Statement Persuasiveness, Statement Strength, And Regulatory Focus On Manipulative Intent Inference

The current research investigates consumers’ perception of information when no influence attempt is perceived. Results indicate that presenting information in a non-persuasive form, such as a warning statement, results in lowering manipulative intent inferences, but only as long as the statement is not strong. Moreover, a difference in manipulative intent inference as a result of statement persuasiveness and statement strength exists only when consumers are promotion focused. Additionally, the current results demonstrate that inference of manipulative intent has a negative effect on perceived quality

Warranty and Price as Quality Signals: The effect of Signal Consistency and Unexpectedness on Product Perception

This dissertation investigates the effect of signal consistency/inconsistency and signal unexpectedness on a consumer\u27s evaluation of a product. It consists of two studies. Study One examines the effect of signal consistency/inconsistency on product quality, where consistent signals are those of the same valance. Prior research has found that a positive cue not only was unable to improve product quality perception, but also had a negative effect on perceived quality when a positive cue was combined with a negative one. The results of Study One indicate that when signals are inconsistent, consumers engage in an attribution process to explain inconsistency. If consumers attribute inconsistency to persuasive motive, then perception of quality decreases. If no persuasive motive is perceived, then consumers tend to discount inconsistent signals and perceived product quality is not affected by those signals. Study One contributes to the literature in three ways. First, the study adds to our knowledge of multiple signals as it increases our understanding of the interaction among extrinsic cues, which is an under-researched area (Purohit and Srivastava 2001). Second, current literature provides adequate explanations of the disappearance of signals\u27 effects on product quality perception; however, no explanation is available for the negative effect of signals on product quality perception, an effect documented by Boulding and Kirmani (1993). This study offers such explanation. Third, the study provides the first empirical examination of the effect of extrinsic cues on the use of persuasion knowledge. Study Two examines the effect of signal unexpectedness on perceived quality. In current literature, credibility is assumed to be based only on the existence of a bond of some kind (Boulding and Kirmani 1993). Using a reputable firm or manipulating a firm\u27s reputation was assumed by previous research to be the primary way to obtain signal credibility (Boulding and Kirmani 1993; Price and Dawar 2002; Agarwal and Teas 2001; Miyazaki, Grewal, and Goodstein 2005). Current findings, therefore, cannot be generalized to new firms that have not established a reputation of any kind. To overcome the problem of basing signals\u27 credibility solely on a firm\u27s reputation, Study Two examines the effect of some signals on the credibility and effectiveness of other signals. The results of Study Two indicate that when faced with a diagnostic cue with ambiguous credibility, consumers use other cues to reach a conclusion about diagnostic cue credibility. When the diagnostic cue is determined to be credible, consumers use that cue when evaluating the product. When the diagnostic cue is determined to not be credible, consumers do not use that cue in evaluating the product. Study Two contributes to the literature in two ways. First, the study provides the first empirical examination of the effect of warranty on perceived quality when warranty is unexpectedly long. Second, this study adds to the literature by building credibility, using signals other than the firm\u27s reputation

Humanitarian aid and relief distribution (HARD) game

© 2020 American Society for Engineering Education. Coordinating humanitarian supply chains can be challenging in terms of getting timely aid to those who need it. While operations in commercial supply chains have been well studied, research studies that address coordination in humanitarian supply chains are still lacking. Unlike commercial supply chains, humanitarian supply chains focus on delivering what customers need rather than want within difficult environments rife with uncertainty. This paper introduces the Humanitarian Aid and Relief Distribution (HARD) Game as an experiential learning tool that explores the potential for increased operational efficiency while balancing decision tradeoffs impacting humanitarian supply chain performance, including beneficiary demand satisfaction, operational costs, and transportation resources utilization. The HARD game is intended for graduate and undergraduate students in courses dealing with topics on supply chain management. It allows students to analyze aspects that significantly impact humanitarian supply chain operations, such as: supply chain coordination and planning, supply chain risks, demand volatility, and competing objectives. Statistical analysis of students\u27 survey responses provide evidence that the HARD game is an effective pedagogical tool that is engaging for students and complementary to the traditional lecture format in the field of supply chain management education

A review on condition-based maintenance optimization models for stochastically deteriorating system

© 2016 Elsevier Ltd Condition-based maintenance (CBM) is a maintenance strategy that collects and assesses real-time information, and recommends maintenance decisions based on the current condition of the system. In recent decades, research on CBM has been rapidly growing due to the rapid development of computer-based monitoring technologies. Research studies have proven that CBM, if planned properly, can be effective in improving equipment reliability at reduced costs. This paper presents a review of CBM literature with emphasis on mathematical modeling and optimization approaches. We focus this review on important aspects of the CBM, such as optimization criteria, inspection frequency, maintenance degree, solution methodology, etc. Since the modeling choice for the stochastic deterioration process greatly influences CBM strategy decisions, this review classifies the literature on CBM models based on the underlying deterioration processes, namely discrete- and continuous-state deterioration, and proportional hazard model. CBM models for multi-unit systems are also reviewed in this paper. This paper provides useful references for CBM management professionals and researchers working on CBM modeling and optimization