A Pilot Investigation of Critical Thinking in Undergraduate Students of Communication Sciences and Disorders

Speech-language pathologists use critical thinking on a daily basis to identify, evaluate, and implement evidence-based practices with their clients. Currently, however, there are minimal data describing the critical thinking of undergraduate students in the field of communication sciences and disorders. Without these data, it is unclear if and how students’ critical thinking differs at various points during their pre-service training. In the present study, we used the Cornell Critical Thinking Test – Level Z to describe the general critical thinking skills of 142 undergraduate students enrolled in two lower- (n = 95) and upper- (n = 47) level courses at a single university. We found no statistically significant differences between these two groups on the CCTT regarding their overall critical thinking performance (p = .068) or their skills of induction (p = .970), deduction (p = .160), observation (p = .384), assumptions (p = .342), or meaning interpretation (p = .155). Upper-level students, however, did consistently score slightly higher than their lower-level counterparts. Faculty should continue to develop undergraduate students’ critical thinking during their course of study. Although critical thinking appears to develop over the course of students’ undergraduate careers, formal instruction might be necessary to develop the skills necessary for successful practice as speech-language pathologists

Round-robin study for ice adhesion tests

Ice adhesion tests are widely used to assess the performance of potential icephobic surfaces and coatings. A great variety of test designs have been developed and used over the past decades due to the lack of formal standards for these types of tests. In many cases, the aim of the research was not only to determine ice adhesion values, but also to understand the key surface properties correlated to low ice adhesion surfaces. Data from different measurement techniques had low correspondence between the results: Values varied by orders of magnitude and showed different relative relationships to one another. This study sought to provide a broad comparison of ice adhesion testing approaches by conducting different ice adhesion tests with identical test surfaces. A total of 15 test facilities participated in this round-robin study, and the results of 13 partners are summarized in this paper. For the test series, ice types (impact and static) as well as test parameters were harmonized to minimize the deviations between the test setups. Our findings are presented in this paper, and the ice- and test-specific results are discussed. This study can improve our understanding of test results and support the standardization process for ice adhesion strength measurements

Evaluation of functional coatings to reduce contamination of aircraft leading edges

The use of new surface coatings on aircraft wings and stabilizers appears to be very promising in terms of clean-liness of the surface as well as potential energy savings when employed in combination with the anti-icing system. The actual limitation of these coatings is linked to their durability in aeronautical conditions, i.e. erosion resistance and weathering… Encouraging results have appeared recently but progress is still to be done

Parameter Study for the Ice Adhesion Centrifuge Test

In this study, we assessed the effects of ice types, test parameters, and surface properties on measurement data of the ice adhesion centrifuge test. This method is often used for the evaluation of low ice adhesion surfaces, although no test standard has been defined yet. The aim of this paper is to improve the understanding of the relevant test parameter and identify crucial criteria to be considered in harmonization and standardization efforts. Results clearly indicate that the ice type (static vs. impact ice) has the greatest impact on the test results, with static ice delivering higher values in a broader data span. This is beneficial for material developers as it eases the evaluation process, but it contradicts the technical efforts to design tests that are as close as possible to realistic technical environments. Additionally, the selected ice type has a significant impact on the relevance of the surface properties (roughness, wettability). Despite the complexity of interactions, a trend was observed that the roughness is the determining surface parameter for high impact velocity ice (95 m/s). In contrast, for tests with static ice, the wettability of the test surface is of higher relevance, leading to the risk of overestimating the icephobic performance of structured surfaces. The results of this paper contribute to the demanding future tasks of defining well-founded test standards and support the development of icephobic surfaces

Parameter Study for the Ice Adhesion Centrifuge Test

In this study, we assessed the effects of ice types, test parameters, and surface properties on measurement data of the ice adhesion centrifuge test. This method is often used for the evaluation of low ice adhesion surfaces, although no test standard has been defined yet. The aim of this paper is to improve the understanding of the relevant test parameter and identify crucial criteria to be considered in harmonization and standardization efforts. Results clearly indicate that the ice type (static vs. impact ice) has the greatest impact on the test results, with static ice delivering higher values in a broader data span. This is beneficial for material developers as it eases the evaluation process, but it contradicts the technical efforts to design tests that are as close as possible to realistic technical environments. Additionally, the selected ice type has a significant impact on the relevance of the surface properties (roughness, wettability). Despite the complexity of interactions, a trend was observed that the roughness is the determining surface parameter for high impact velocity ice (95 m/s). In contrast, for tests with static ice, the wettability of the test surface is of higher relevance, leading to the risk of overestimating the icephobic performance of structured surfaces. The results of this paper contribute to the demanding future tasks of defining well-founded test standards and support the development of icephobic surfaces

Icephobic Coating Based on Novel SLIPS Made of Infused PTFE Fibers for Aerospace Application

The development of slippery surfaces has been widely investigated due to their excellent icephobic properties. A distinct kind of an ice-repellent structure known as a slippery liquid-infused porous surface (SLIPS) has recently drawn attention due to its simplicity and efficacy as a passive ice-protection method. These surfaces are well known for exhibiting very low ice adhesion values (τice < 20 kPa). In this study, pure Polytetrafluoroethylene (PTFE) fibers were fabricated using the electrospinning process to produce superhydrophobic (SHS) porous coatings on samples of the aeronautical alloy AA6061-T6. Due to the high fluorine–carbon bond strength, PTFE shows high resistance and chemical inertness to almost all corrosive reagents as well as extreme hydrophobicity and high thermal stability. However, these unique properties make PTFE difficult to process. For this reason, to develop PTFE fibers, the electrospinning technique has been used by an PTFE nanoparticles (nP PTFE) dispersion with addition of a very small amount of polyethylene oxide (PEO) followed with a sintering process (380 °C for 10 min) to melt the nP PTFE together and form uniform fibers. Once the porous matrix of PTFE fibers is attached, lubricating oil is added into the micro/nanoscale structure in the SHS in place of air to create a SLIPS. The experimental results show a high-water contact angle (WCA) ≈ 150° and low roll-off angle (αroll-off) ≈ 22° for SHS porous coating and a decrease in the WCA ≈ 100° and a very low αroll-off ≈ 15° for SLIPS coating. On one hand, ice adhesion centrifuge tests were conducted for two types of icing conditions (glaze and rime) accreted in an ice wind tunnel (IWT), as well as static ice at different ice adhesion centrifuge test facilities in order to compare the results for SHS, SLIPs and reference materials. This is considered a preliminary step in standardization efforts where similar performance are obtained. On the other hand, the ice adhesion results show 65 kPa in the case of SHS and 4.2 kPa of SLIPS for static ice and <10 kPa for rime and glace ice. These results imply a significant improvement in this type of coatings due to the combined effect of fibers PTFE and silicon oil lubricant

Runback water behavior on hydro-phobic/philic surfaces of circular cylinder placed in flow field

Coating has been recently considered as having good potential for use in preventing in-cloud icing on the leading edge of the lifting surfaces of an aircraft in cold climates. In terms of wettability, a coat may exhibit hydrophobicity or hydrophilicity depending on its specific properties. The same applies to the ice adhesion strength, which maybe either high or low. It is thus necessary to determine which type of anti-icing or de-icing coat would be appropriate for a particular application in order to fully utilize its specific properties. Notwithstanding, a coat is incapable of preventing ice accretion by itself, and a perfect ice phobic coat is yet to be developed. Coating is also sometimes applied to the surfaces of electrical heaters and load-applying machines to enable them to function more effectively and use less energy. The coating used for an electric heater, for instance, should be hydrophobic because of the need for rapid removal of molten water from the surface. The nanostructured surface of a coating of this type produces a lotus-like effect. During in-cloud icing on the surfaces of the wings of an aircraft, minute supercooled airborne water droplets collide with the leading edges of the wings at almost the same speed as that of the aircraft. If the wing surface is hydrophobically coated and heated by an installed heating system, the droplets would remain in the liquid state on the leading edge immediately after impingement, and then begin to move toward the trailing edge. It has been observed from icing wind tunnel tests conducted on scale airfoil models with hydrophobically coated surfaces that the molten water droplets detach themselves from the surface after attaining a particular size. In contrast, if the surface is hydrophilic, the water would move backward in rivulets along the surface. In the present study, we conducted wind tunnel tests at room temperature using circular cylindrical models to determine the precise behavior of water droplets on the model surfaces, which were variously modified for super hydrophobicity and hydrophilicity. The models were designed to ooze water from their windward surfaces and were set inside the closed test section of the wind tunnel. A high-speed camera was used to monitor how the water droplets behaved on the surfaces of the cylinders for different air speeds. The results provide some fundamental insights into the behavior of water on a coated cylindrical surface in a flow field, and would be useful for the design of coating-type aircraft ice protection systems

Harsh-environment-resistant OH-vibrations-sensitive mid-infrared water-ice photonic sensor

State-of-the-art ultrahigh-sensitivity photonic sensing schemes rely on exposing the evanescent field of tightly confined light to the environment. Yet, this renders an inherent fragility to the device, and since adding a protective layer disables light exposure, there exists a technology gap for highly sensitive harsh-environment-resistant surface photonic sensors. Here, a novel type of mid-infrared waveguide sensors is reported which exploit vibrational resonance-driven directional coupling effects besides absorption, with optical sensing elements that can be buried (≈1–10 µm) and resist systematic exposure to industrial environments without failure. A harsh-environment-resistant, fiber-coupled, surface sensor for monitoring the structural phase of water (liquid-supercooled-solid), as well as the type of ice microstructure (clear rime), is shown. It is demonstrated how this type of sensor can be designed to detect ice layers with nanometric (≈100 nm) to microscopic (≈30 µm or higher) thicknesses, and the first experimental tests both in optical laboratory and in icing wind tunnel inflight aircraft simulation tests are reported