Quantitative,Qualitative, and Mixed Research Methods in Engineering Education

The purpose of this research review is to open dialog about quantitative, qualitative, and mixed research methods in engineering education research. Our position is that no particular method is privileged over any other. Rather, the choice must be driven by the research questions. For each approach we offer a definition, aims, appropriate research questions, evaluation criteria, and examples from the Journal of Engineering Education. Then, we present empirical results from a prestigious international conference on engineering education research. Participants expressed disappointment in the low representation of qualitative studies; nonetheless, there appeared to be a strong preference for quantitative methods, particularly classroom‐based experiments. Given the wide variety of issues still to be explored within engineering education, we expect that quantitative, qualitative, and mixed approaches will be essential in the future. We encourage readers to further investigate alternate research methods by accessing some of our sources and collaborating across education/social science and engineering disciplinary boundaries.     

Auditory habituation in young and older adults: The verbal transformation effect.

In 3 experiments, auditory massed repetition was used to examine age-related differences in habituation by means of the verbal transformation paradigm. Participants heard 10 words (5 high frequency and 5 low frequency), each presented 180 times, and they reported perceived changes in the repeated words (verbal transformations). In these experiments, older adults reported fewer illusory percepts than young adults. Older adults' loss of auditory acuity and slowing of processing, stimulus degradation (in young adults), and instructions biasing the report of these illusory percepts did not account for the fewer illusory percepts reported by the older adults. These findings suggest that older adults' reduced susceptibility to habituation arises from centrally located declines in the transmission of information within the word recognition pathway. The discussion focuses on the implications that these age-related declines may have on word identification during on-line speech perception. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Experimental Results on Centrifugated GFRP Poles for Electric Lifelines

In this paper the results of an experimental investigation on glass fiber reinforced plastic (GFRP) centrifugated transmission utility poles are discussed. The study is principally aimed to analyze the effect of manufacturing process on the mechanical properties of the poles. The results of the experimental investigation are especially concerned with the analysis of some parameters that mostly affect the tensile behavior of the poles in terms of stiffness and strength; among these, physical parameters such as glass percentage and thickness, and mechanical parameters such as longitudinal modulus and tensile strength are considered. The analysis evidenced the high quality of the manufacturing process in providing a product that has low tolerances in the experimental values of dimensional and tensile properties of the poles. An effective stiffness is defined to model satisfactorily the experimental tensile response and to provide a design tool for the mechanical properties of the poles. This parameter, which directly includes the dependency on glass content and thickness values, appears an effective tool in the prediction of the poles' structural response.     

A Monolithic Force‐Sensitive 3D Microgripper Fabricated on the Tip of an Optical Fiber Using 2‐Photon Polymerization

Microscale robotic devices have myriad potential applications including drug delivery, biosensing, cell manipulation, and microsurgery. In this work, a tethered, 3D, compliant grasper with an integrated force sensor is presented, the entirety of which is fabricated on the tip of an optical fiber in a single‐step process using 2‐photon polymerization. This gripper can prove useful for the interrogation of biological microstructures such as alveoli, villi, or even individual cells. The position of the passively actuated grasper is controlled via micromanipulation of the optical fiber, and the microrobotic device measures approximately 100 µm in length and breadth. The force estimation is achieved using optical interferometry: high‐dimensional spectral readings are used to train artificial neural networks to predict the axial force exerted on/by the gripper. The design, characterization, and testing of the grasper are described and its real‐time force‐sensing capability with an accuracy below 2.7% of the maximum calibrated force is demonstrated.     

Role of Fiber Reinforced Plastic Sheets in Shear Response of Reinforced Concrete Beams: Experimental and Analytical Results

The paper is principally aimed at analyzing the role of externally applied fiber reinforced plastic (FRP) sheets in the shear ultimate behavior of reinforced concrete elements. A theoretical model for predicting the shear resisting contribution of FRP sheets is illustrated. The proposal is based on a complete equilibrium/compatibility approach for reinforced concrete beams failing in shear and considers the possible interactions between the composite contribution and the resisting mechanisms of an ordinary reinforced concrete beam. The proposal is discussed and tested by means of an experimental investigation carried out on beams reinforced by glass FRP composite sheets with a shear span to depth ratio equal to 3. Further comparisons are then performed that consider the predictions of other existing approaches reported in the literature.     

Electroless deposited Ni–P alloys: corrosion resistance mechanism

Electroless Ni–P alloys are produced as coatings on a broad variety of substrates. They exhibit a corrosion resistance that is superior to pure nickel but do not form a NiO oxide film (passive film) as pure nickel does. Despite the fact that many mechanisms have been proposed to explain this superior corrosion behaviour, no consensus has yet been reached. In this work electrochemical and XPS surface analytical methods have been combined in order to gain a deeper insight into the mechanisms underlying the corrosion resistance of electroless deposited Ni–P alloys with phosphorus content between 18 and 22 at.%. The anodic polarization curves in acidic and neutral solutions confirm a broad current plateau followed by a region with increasing current density. During potentiostatic polarization in the plateau region the current decays according to a power law with exponent ca. −0.5 indicating diffusion-limited dissolution of nickel. XPS/XAES measurements performed after potentiostatic polarization show that phosphorus is present in three different chemical environments. Based on the Auger parameter concept and on the chemical state plot, the three phosphorus states were assigned to phosphorus in the bulk alloy, phosphates and an intermediate phosphorus compound attributed to elemental phosphorus. Angle-resolved XPS analysis has shown that the elemental phosphorus is enriched at the interface between the alloy and the outermost surface in contact with the corrosive solution. These results suggest the following conclusions: the high corrosion resistance of electroless deposited Ni–P alloys can be explained by a strong enrichment of elemental phosphorus at the interface which limits the dissolution of nickel via a diffusion mechanism. A complementary explanation––not yet advanced––for the high corrosion resistance may lie in the electronic state of nickel in the Ni–P alloys.     

Evaluating the performance of paper people.

111 studies published, 1975–1984, were grouped into 5 major substantive categories, and a comparative meta-analysis was used to contrast the outcomes of paper people studies (i.e., raters read performance vignettes and then rated the performance of several hypothetical ratees) to those of similar studies in which ratings were based on the direct or indirect observation (e.g., via videotape) of ratee behavior. Effect sizes were found to be significantly larger in paper people studies, although this difference was not uniform across all research areas. Results are discussed in terms of differences in signal-to-noise ratios across the 2 methods. (101 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Simple Model for Bond Behavior of Masonry Elements Strengthened with FRP

The aim of the present paper is the development of a simple procedure for the analysis of the bond behavior of fiber-reinforced polymer (FRP) sheets or plates externally applied to masonry supports for the strengthening or repair of masonry constructions. The procedure allows evaluation of the bond strength and the fracture energy developed during the debonding process through simple formulas based on a few parameters, evaluated either by standard tests performed on the materials making up the support and the strengthening system or by theoretical considerations. A brief discussion on the main experimental evidence and the theoretical models provided by the literature is also reported in this paper. The comparison between the theoretical results obtained by applying the proposed procedure and the experimental data deduced from literature is carried out.