Osmotically driven membrane processes (ODMPs) such as forward osmosis (FO) and pressure retarded osmosis (PRO) are extensively investigated for utilization in a broad range of applications. In ODMPs, the operating conditions and membrane properties play more critical roles in mass transport and process performance than in pressure-driven membrane processes. Search of the literature reveals that ODMP membranes, especially newly developed ones, are tested under different temperatures, draw solution compositions and concentrations, flow rates, and pressures. In order to compare different membranes, it is important to develop standard protocols for testing of membranes for ODMPs. In this article we present a standard methodology for testing of ODMP membranes based on experience gained and operating conditions used in FO and PRO studies in recent years. A round-robin testing of two commercial membranes in seven independent laboratories revealed that water flux and membrane permeability coefficients were similar when participants performed the experiments and calculations using the same protocols. The thin film composite polyamide membrane exhibited higher water and salt permeability than the asymmetric cellulosebased membrane, but results with the high permeability thin-film composite membrane were more scattered. While salt rejection results in RO mode were relatively similar, salt permeability coefficients for both membranes in FO mode were more varied. Results suggest that high permeability ODMP membranes should be tested at lower hydraulic pressure in RO mode and that RO testing be conducted with the same membrane sample used for testing in FO mode. AbstractOsmotically driven membrane processes (ODMP) such as forward osmosis (FO) and pressure retarded osmosis (PRO) are extensively investigated for utilization in a broad range of applications. In ODMPs, the operating conditions and membrane properties play more critical roles in mass transport and process performance than in pressure-driven membrane processes.Search of the literature reveals that ODMP membranes, especially newly developed ones, are tested under different temperatures, draw solution compositions and concentrations, flowrates, and pressures. In order to compare different membranes, it is important to develop standard protocols for testing of membranes for ODMP. In this article we present a standard methodology for testing of ODMP membranes based on experience gained and operating conditions used in FO and PRO studies in recent years. A round-robin testing of two commercial membranes in seven independent laboratories revealed that water flux and membrane permeability coefficients were similar when participants performed the experiments and calculations using the same protocols. The thin film composite polyamide membrane exhibited higher water and salt permeability than the asymmetric cellulose-based membrane, but results with the high permeability thin-film composite membrane were more scattered. While salt rejection results in RO mode were...
Background Many students may not respond strongly to instruction that they do not perceive as engaging. One pedagogical approach to help engage students involves the use of games. Educational games can provide students with a motivating and stimulating environment while providing them with immediate feedback to promote learning.Purpose This systematic review examines research focused on the implementation of games to teach undergraduate engineering students; it summarizes prevailing features and cites examples from a variety of engineering disciplines. Scope/MethodThe systematic review was conducted through a detailed search of Science Direct journals and the Scopus, Web of Science, Compendex/Inspec, and ERIC Education Research Abstract databases using terms pertinent to games in engineering education. A total of 191 papers was included after application of the inclusion/exclusion criteria. After screening those to determine if assessment of student learning outcomes was performed, 62 papers were found suitable for more detailed analysis. ConclusionsResearch on the implementation of games in undergraduate engineering classrooms has shown that, despite diverse forms of assessment applied, there is a general trend that both student learning and attitudes are improved by game-based activities. However, since only a relatively small subset of the literature demonstrates a systematic, validated approach in assessment, significant opportunities remain for future research.Despite many advances in active learning techniques and their dissemination, the predominant method of student instruction remains the transmission model: information is a quantifiable resource, and the instructor's role is to transmit that information to learners, who must store and act upon it (Tishman, Jay, & Perkins, 1993). While the transmission model can be effective when teaching for understanding, it may be less effective in developing skills and providing experiences, such as communication, teamwork, and creativity.Recently, game-based learning has come to the forefront of potential pedagogical methods for educating students and providing them with the motivation and opportunities to practice Journal of Engineering Education V C 2016 ASEE.
Closed-loop pressure retarded osmosis (PRO) has been recently proposed as a means of transforming unusable forms of energy, such as waste heat, into valuable electricity. The process, which is also referred to as an osmotic heat engine (OHE), also enables a form of osmotic grid storage for intermittently available renewable energy sources, where available energy is stored as an osmotic potential and that energy is released via PRO when energy demand is high. The OHE has the potential to generate greater power than conventional open loop PRO because the draw solution can be engineered to have very high osmotic pressures, via enhanced temperature, solute concentration, or a combination of both. These variables change fluid properties and the performance of the membrane, which may or may not be beneficial to overall OHE operation. Using a custom-built, bench-top PRO system, a commercially available forward osmosis membrane from Hydration Technology Innovations TM (HTI) was evaluated for water flux and power density at two temperatures (20°C and 40°C) and three draw solution concentrations (0.5, 1.0, and 1.5 M sodium chloride) that are similar to temperatures and draw solution osmotic pressures capable in an osmotic heat engine. In general, power density increased with increasing draw concentration and temperature, with the highest observed power © 2015. This manuscript version is made available under the Elsevier user license http://www.elsevier.com/open-access/userlicense/1.0/ densities (18.0 ± 2.3 W/m 2 ) were measured at 20.7 bar (300 psi) using a 1.5 M sodium chloride draw solution at 40°C. Experimental data compared favorably to predicted performance using conventional PRO flux and power density models.
Gamification, or the introduction of game-like mechanics into non-game contexts, has received increasing attention recently, largely for its perceived ability to motivate participants into desired courses of action by making mandatory or mundane tasks rewarding in some way. Examples of this in the business world include frequent flyer reward programs, social programs such as FourSquare or Facebook Check In, and app-type gamification of to-do lists, weight-loss programs, or exercise programs.Application of gamification to education is a logical extension, as it has the potential to motivate students to perform extra learning tasks that they might not otherwise do by couching those tasks in the larger context of a game, or by providing small but tangible non-grade rewards for their completion. To study this phenomenon, we chose to overlay a collaborative team-based game context over the traditional senior capstone chemical engineering laboratory course. As a laboratory course, the structure is such that students are naturally clustered into teams working on different experiments. This allowed us to easily divide the students into randomly assigned teams ('guilds' in our example) that were united by a common purpose -completing their major experiment. By completing required tasks such as lab reports and presentations, students earned XP (experience points), which translated directly into a traditional grade. In addition, other, optional tasks were added that could earn a student additional XP (effectively extra credit), but also another resource, called Reputation. While reputation did not affect a student's grade directly, by working collectively with other students in their guild, students could pool Reputation to effectively 'win' the game. In this context, the guild with the most reputation at the end of the semester was allowed to choose from several rewards (dinner out with the faculty, the ability to choose an experiment the following semester, a small boost to one of their best grades, etc.). Optional tasks were ones that the instructors thought would benefit the students, but in practice, without incentivization, few students attempted. Examples include peer evaluation of their work, seeking out and using external references in their writing, and performing data analysis during the course of the experiment and using that information to modify their experimental plan.Both pre-and post-course surveys were carried out, which collected data on the students' experience with a multitude of game types, as well as their personal habits. Additionally, their attitude and perceptions about gamification and our particular implementation were surveyed both prior to the start of the class and after the semester ended to compare differences. After one semester of implementation, comparison of scores on lab reports from a non-gamified offering of the class with the gamified version showed no statistical difference. However, the student participation in incentivized tasks was high, and showed a broad appeal across different...
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