Using Assessment as a Teaching Tool

Author(s):  
Joa˜o E. M. Marques

Based upon two personal beliefs, with regard to teaching that firstly "teaching is helping others to discover" and secondly that "assessment is a necessary inconvenience", a method has been developed in teaching Fluid Dynamics to undergraduate students, in a Mechanical Engineering Course. The main goal of this method is changing from a traditional theoretical approach of teaching "what is in the book" to a much more practical confrontation between theory and what can be found in laboratory experiment. The program contents are covered by four laboratory apparatuses: • Reynolds experiment, • Head losses in tubes, • Hydraulic turbines, • Centrifugal pumps, which are presented to all the students during a particular class so they can prepare for their next return to the laboratory, now organized into small groups. Meanwhile, each group must define their specific objectives and work planning, so the students can accomplish the experiments off-line, with the laboratory supervisor's eventual help and subsequent report must be written within a determined period. The main results achieved a success rate which has risen from about 50%, of the evaluated students before setting up the method to 70%, but keeping the same lecturer, i.e. the same quality demand.

2009 ◽  
Vol 133 (9) ◽  
pp. 1457-1462
Author(s):  
Anurag Saxena ◽  
Raenelle Nesbitt ◽  
Punam Pahwa ◽  
Sheryl Mills

Abstract Context.—Second-year medical students are introduced to many new terms and concepts in a short time frame in the hematology system and the neoplasia section of the undergraduate pathology course. It is a challenge to provide adequate practice and necessary repetition to reinforce key concepts. Objective.—To determine student perceptions of the usefulness of crosswords as a quick and effective way to reinforce essential concepts and vocabulary. Design.—Crosswords with ensured content validity built on a free Internet resource were completed by the students in collaborative and cooperative groups of 6 to 7 with a reward for the first group to successfully complete the puzzle. Student perceptions of the value of crosswords for their learning were examined in 2003 (39 students) with a survey of yes or no responses and in 2004 (41 students) with a survey using questions with a 5-point Likert scale. Results.—Many students (37 of 39 in 2003 and 24 of 41 in 2004) indicated that crosswords were useful and contributed to their learning. Specifically, crosswords were found to be useful for identifying key concepts and vocabulary and for their collaborative and competitive aspects. Written and informal comments indicated student enthusiasm for and a desire to participate in more of these exercises. Students have transferred this review strategy to other classes and the peer teachers have expressed an interest in it as an adjunct teaching tool. Conclusions.—The judicious use of crosswords was useful for near transfer content and provided an opportunity to discuss and recall essential concepts, think critically, and collaborate in small groups.


2020 ◽  
Vol 4 (1) ◽  
pp. 10-19
Author(s):  
Dahlia Dahlia

The development of instructional especially media of a herbarium book is an innovation that aims to assist students in searching directly the object of leaf morphology studies. This development research starts from the needs analysis stage which is used to gather information, planning in media making, media design, media making, after that product validation by a team of media experts and material experts, then testing individual products, small groups and large groups. The subject of this product testing were students of the Biology Education Study Program at Pasir Pengaraian University. The results of the validation by the material experts showed that the quality of learning media using the herbarium book on leaf morphology material was included in the "very feasible" criteria, with an average score of 86.46%. The results of validation by media experts are included in the "very feasible" criteria, with an average score of 88.54%. Individual assessment obtained the criteria of "very feasible", with an average score of 84.16%. Judgement from small groups obtained a percentage of eligibility of 81.45% with very feasible criteria, and judgement from large groups of 83.95% with "very feasible" criteria. The results of the development of herbarium book media are very decent.


1961 ◽  
Vol 83 (1) ◽  
pp. 74-78 ◽  
Author(s):  
C. P. Kittredge

Centrifugal pumps may be used to advantage as small hydraulic turbines where low initial cost is imperative. Pump and turbine characteristics are presented for typical units and a procedure for pump selection is discussed.


Fluids ◽  
2020 ◽  
Vol 5 (1) ◽  
pp. 40 ◽  
Author(s):  
Andrei Medved ◽  
Riley Davis ◽  
Paula A. Vasquez

The Langevin equations (LE) and the Fokker–Planck (FP) equations are widely used to describe fluid behavior based on coarse-grained approximations of microstructure evolution. In this manuscript, we describe the relation between LE and FP as related to particle motion within a fluid. The manuscript introduces undergraduate students to two LEs, their corresponding FP equations, and their solutions and physical interpretation.


2007 ◽  
Vol 25 (2) ◽  
pp. 163-172 ◽  
Author(s):  
David Rawlings ◽  
Ann Locarnini

The Creativity Scale for Diverse Domains (CSDD) of Kaufman and Baer (2004), measures self-reported creativity in nine different domains, as well as “creativity in general.” The study reports a criterion validation of the scale, using small groups of professional scientists and artists, in addition to two groups of undergraduate students planning major studies in the arts/humanities or in science/mathematics. Similar patterns of inter-correlation between items, and a similar factor structure, were found to those reported in the original study. In support of the validity of the scale, professional scientists were clearly highest on items measuring creativity in science and mathematics; professional artists on items measuring creativity in art and general creativity. There were minimal differences between the student groups. The results provide substantial support for the usefulness of the CSDD when a short measure of creativity in different areas is sought.


2019 ◽  
Vol 141 (10) ◽  
Author(s):  
Tingcheng Wu ◽  
Luis San Andrés

In multiple stage centrifugal pumps, balance pistons, often comprising a grooved annular seal, equilibrate the full pressure rise across the pump. Grooves in the stator break the evolution of fluid swirl and increase mechanical energy dissipation; hence, a grooved seal offers a lesser leakage and lower cross-coupled stiffness than a similar size uniform clearance seal. To date, bulk-flow modelbulk-flow models (BFMs) expediently predict leakage and rotor dynamic force coefficients of grooved seals; however, they lack accuracy for any other geometry besides rectangular. Note that scalloped and triangular (serrated) groove seals are not uncommon. In these cases, computational fluid dynamics (CFD) models seals of complex shape to produce leakage and force coefficients. Alas, CFD is not yet ready for routine engineer practice. Hence, an intermediate procedure presently takes an accurate two-dimensional (2D) CFD model of a smaller flow region, namely a single groove and adjacent land, to produce stator and rotor surface wall friction factors, expressed as functions of the Reynolds numbers, for integration into an existing BFM and ready prediction of seal leakage and force coefficients. The selected groove-land section is well within the seal length and far away from the effects of the inlet condition. The analysis takes three water lubricated seals with distinct groove shapes: rectangular, scalloped, and triangular. Each seal, with length/diameter L/D = 0.4, has 44 grooves of shallow depth dg ∼ clearance Cr and operates at a rotor speed equal to 5,588 rpm (78 m/s surface speed) and with a pressure drop of 14.9 MPa. The method validity is asserted when 2D (single groove-land) and three-dimensional (3D) (whole seal) predictions for pressure and velocity fields are compared against each other. The CFD predictions, 2D and 3D, show that the triangular groove seal has the largest leakage, 41% greater than the rectangular groove seal does, albeit producing the smallest cross-coupled stiffnesses and whirl frequency ratio (WFR). On the other hand, the triangular groove seal has the largest direct stiffness and damping coefficients. The scalloped groove seal shows similar rotordynamic force coefficients as the rectangular groove seal but leaks 13% more. For the three seal groove types, the modified BFM predicts leakage that is less than 6% away from that delivered by CFD, whereas the seal stiffnesses (both direct and cross-coupled) differ by 13%, the direct damping coefficients by 18%, and the added mass coefficients are within 30%. The procedure introduced extends the applicability of a BFM to predict the dynamic performance of grooved seals with distinctive shapes.


Author(s):  
Carlos Luis Moreno ◽  
Alejandro Fuenmayor ◽  
Gilberto Núñez ◽  
Jesús De Andrade ◽  
Ricardo Noguera ◽  
...  

Centrifugal pump performance is affected when pumping viscous liquids, requiring a larger power input than the same pump handling water. In applications of chemical, civil, environmental, and mechanical engineering that involve centrifugal pumps, it is a challenge to accurately estimate and even more of a challenge to improve their performance when handling viscous liquids. When accurate performance data is needed, difficult experiments must be conducted with the operating viscous flow. The extension of the applicability of numerical techniques for solving fluid dynamics (CFD) permits the consideration of these tools as a definite possibility for predicting the performance of centrifugal pumps with viscous flows. The purpose of this study is to perform a 3D-CFD steady-state simulation of three different configurations of centrifugal pumps. The first is an impeller-diffuser pump (ns = 19) taken from an ESP model. The second is a Francis Pump-Turbine (ns = 28). Finally, the third configuration possesses an impeller and volute (ns = 32). The objective is to characterize and evaluate their performances with four different fluids from 1 to 420 cSt. These are: water at 25°C, SAE10 and SAE30 oils, and Fuel Oil Medium (FOM). For water flow conditions, the numerical results were compared with experimental data, and found to be consistent with global performance parameters. With regard to the higher viscosity fluids, the CFD calculation was compared with those obtained through the standard empirical method (ANSI/HI9.6.7). This resulted in good agreement between the performance results. The commercial software ANSYS-CFX was used for the CFD calculations. The resulting pump performance curve (head, hydraulic efficiency and power output) is consistent with that expected by theory. In general, as the viscosity of fluids increases, the hydraulic energy losses increase. Of the three pumps, slip factor for SAE30 oil was larger for all volumetric flows since it features the best guidance of the flow in the impeller blade passage. For the ns32 pump and the pump-turbine ns28, the volute losses rose from water to FOM, just like the impeller hydraulic losses. For these two turbo machines, the impeller losses were larger than volute losses. For the pumps with volute, the effects of fluid viscosity on the radial forces were evaluated. It was found that the radial forces decrease when the viscosity increases. This paper attempts to contribute to a better understanding of fluid dynamics within centrifugal pump impellers handling viscous fluids, and intends to shed more light on the approaches that performance prediction models should follow in the future.


Author(s):  
Ivaylo Nedyalkov ◽  
Martin Wosnik

Computational Fluid Dynamics (CFD) has become a widely used tool in industry as the cost for simulations is usually lower than the cost for multiple experiments. CFD is an effective tool for comparing design alternatives, investigating specific flow features and in some cases it may be the only feasible option for studying engineering flows. As a result, the demand for mechanical engineers with CFD skills keeps increasing. Nevertheless CFD is still not adequately presented in undergraduate engineering curricula, which can lead to expensive mistakes, if for example it is relied on without understanding its limitations. One excellent platform for CFD, which can be introduced to fluid mechanics classes, is the open-source environment OpenFOAM, which is widely used in both academia and industry. In addition to being open-source, OpenFOAM code can be viewed and modified by the user, and a wide range of modules for OpenFOAM are available with new modules being developed constantly. One major disadvantage, however, is that OpenFOAM has a rather steep learning curve and although there are many resources available online, it is difficult to find short introductory courses. A tutorial was developed to provide a brief introduction to OpenFOAM and allow the students to perform simple simulations. Upon completing the tutorial, the students can build their own simulations. The tutorial covers geometry, mesh, boundary and initial conditions, solvers, schemes, post processing, and some additional features, such as shell scripts and parallel processing. A large portion of the tutorial is devoted to the geometry and mesh generation as this is one of the more challenging aspects of OpenFOAM compared to conventional graphical user interface CFD packages. Nevertheless, the students are exposed to the importance of properly setting the other simulation parameters through simple examples — e.g., comparing 2D channel flow simulations using potential flow and using turbulence modeling. One crucial aspect of the tutorial is that students are encouraged to experiment with deliberate modifications of the simulations to experience and understand how some of them do not provide reasonable results. Although the tutorial is rather brief and does not cover the topics in much detail, it aims to familiarize students with the basics of OpenFOAM, so that they can better understand other relevant resources. The OpenFOAM tutorial offers an alternative introduction to CFD compared to commercial CFD packages, which may not be readily available. The tutorial has already been utilized for three consecutive years at the University of New Hampshire, mostly by undergraduate students who worked/are working on senior projects involving CFD. The feedback has been generally positive.


1990 ◽  
Vol 66 (2) ◽  
pp. 503-508 ◽  
Author(s):  
John D. Martin ◽  
Garland E. Blair ◽  
Judy R. Bledsoe

The subjects, 60 undergraduate students, were administered the Test of Nonverbal Intelligence (TONI) individually. The Shipley Institute of Living Scale was administered in small groups. A Pearson correlation of .56 was obtained for TONI Quotients, Forms A and B. TONI Quotients, Forms A and B, correlated with Shipley estimated WAIS—R IQ .50 and .46, respectively, and corrected to .71 and .64, with Shipley Total T scores, .52 and .44, respectively (corrected to .71 and .61), with Shipley Abstraction T scores, .51 and .42, respectively (corrected, .63 and .52), and with Shipley Vocabulary T scores .26 and .32, respectively (corrected to .63 and .52). TONI scores seem more closely related to Shipley Total and Abstraction scores than to Shipley Vocabulary.


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