Enhancing the Learning of Surface Wave Dynamics in a Modern Mechanical Engineering Program

Author(s):  
Afshin Goharzadeh ◽  
Arman Molki

This paper outlines a proposed low-cost experimental setup for characterization of surface waves that was designed and fabricated in conjunction with a senior design project. The proposed experimental setup will enhance the student’s learning of surface waves at water-air interface inside an open transparent channel. The experimental study is based on the flow visualization of water waves combined with measurement of water level using a conductance wave height probe. The detail of the data acquisition system and the characteristics of the wave probes are presented. Finally a teaching strategy for implementing the water wave experimental setup in a Mechanical Engineering curriculum is discussed.

Author(s):  
Afshin Goharzadeh ◽  
Arman Molki ◽  
Peter Rodgers ◽  
Shrinivas Bojanampati

This paper outlines a proposed low-cost experimental setup for the measurement of two-phase liquid-gas flows in a vertical column. The objective of the test facility is to familiarize students with the challenges in applying measurement techniques to characterize such flows. The test facility incorporates two complementary intrusive and non-intrusive measurement techniques for detecting and studying the dynamics of air bubbles transported in water. The intrusive measurement method uses conductivity probes, while the non-intrusive technique is laser based. For both measurement techniques, details of the data acquisition system and the characteristics of sensors employed are presented. In addition, the teaching strategy is discussed for implementing the use of the proposed two-phase flow experimental setup in a Mechanical Engineering curriculum.


Author(s):  
Musa K. Jouaneh ◽  
William J. Palm

Most Mechanical Engineering curricula include courses in system dynamics, controls, mechatronics, and vibrations. At most schools, these courses do not have a laboratory component. Even at schools that have such a component, laboratory access is often limited, and thus there is a need to increase students’ laboratory experience. This paper addresses the development and initial testing of instructional material in the form of take-home software and hardware kits that can be used to perform laboratory experiments and measurements at home to illustrate system dynamics concepts. Rather than having students perform an experiment in the university laboratory, the students are given a compact, low cost software and hardware kit with which they can perform an experiment at home using only their PC. The kits are designed so that the experiments can be conducted on a provided experimental setup such as a DC motor/tachometer system or can be used to perform dynamic measurements on engineering systems that are available at home such as motor powered devices and heating/cooling systems. The take-home kit consists of three components. The first component is a hardware interface board that is built around a PIC18F4550 microcontroller which interfaces with the student’s PC and with the experiment hardware. The second component is a Windows based user interface program that is loaded on the student’s PC and is used to run the experiment and collect data. The third component is the actual experimental setup or the sensor system to perform the measurement. Fifty five kits have been fabricated to perform five different experiments. Two of these experiments were tested in two courses in the mechanical engineering department at the University of Rhode Island. The paper discusses the design of the kit components, the details of the experiments, as well the initial experiences gained from using this new approach for laboratory experimentation.


Electronics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 140
Author(s):  
Lichen Liu ◽  
Ziping Cao ◽  
Min Chen ◽  
Jun Jiang

This paper reports the fabrication and characterization of (Bi0.48Sb1.52)Te3 thick films using a tape casting process on glass substrates. A slurry of thermoelectric (Bi0.48Sb1.52)Te3 was developed and cured thick films were annealed in a vacuum chamber at 500–600 °C. The microstructure of these films was analyzed, and the Seebeck coefficient and electric conductivity were tested. It was found that the subsequent annealing process must be carefully designed to achieve good thermoelectric properties of these samples. Conductive films were obtained after annealing and led to acceptable thermoelectric performance. While the properties of these initial materials are not at the level of bulk materials, this work demonstrates that the low-cost tape casting technology is promising for fabricating thermoelectric modules for energy conversion.


Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1327
Author(s):  
Dwinanto Sukamto ◽  
Monica Siroux ◽  
Francois Gloriant

The building sector is the largest consumer of energy, but there are still major scientific challenges in this field. The façade, being the interface between the exterior and interior space, plays a key role in the energy efficiency of a building. In this context, this paper focuses on a ventilated bioclimatic wall for nearly zero-energy buildings (NZEB). The aim of this study is to investigate an experimental setup based on a hot box for the characterization of the thermal performances of the ventilated wall. A specific ventilated prototype and an original thermal metrology are developed. This paper presents the ventilated prototype, the experimental setup, and the experimental results on the thermal performances of the ventilated wall. The influence of the air space thickness and the air flow rate on the thermal performances of the ventilated wall is studied.


Sensors ◽  
2020 ◽  
Vol 20 (9) ◽  
pp. 2471 ◽  
Author(s):  
Daniel Flor ◽  
Danilo Pena ◽  
Luan Pena ◽  
Vicente A. de Sousa ◽  
Allan Martins

Vehicular acoustic noise evaluations are a concern of researchers due to health and comfort effects on humans and are fundamental for anyone interested in mitigating audio noise. This paper focuses on the evaluation of the noise level inside a vehicle by using statistical tools. First, an experimental setup was developed with microphones and a microcomputer located strategically on the car’s panel, and measurements were carried out with different conditions such as car window position, rain, traffic, and car speed. Regression analysis was performed to evaluate the similarity of the noise level from those conditions. Thus, we were able to discuss the relevance of the variables that contribute to the noise level inside a car. Finally, our results revealed that the car speed is strongly correlated to interior noise levels, suggesting the most relevant noise sources are in the vehicle itself.


Author(s):  
Pedro Coimbra ◽  
Stefania Faria ◽  
Mario Vala ◽  
Joao Felicio ◽  
Carlos Fernandes ◽  
...  

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 459
Author(s):  
Ignacio Cazcarro ◽  
Albert E. Steenge

This article originates from the theoretical and empirical characterization of factors in the World Trade Model (WTM). It first illustrates the usefulness of this type of model for water research to address policy questions related to virtual water trade, water constraints and water scarcity. It also illustrates the importance of certain key decisions regarding the heterogeneity of water and its relation to the technologies being employed and the prices obtained. With regard to WTM, the global economic input–output model in which multiple technologies can produce a “homogeneous output”, it was recently shown that two different mechanisms should be distinguished by which multiple technologies can arise, i.e., from “technology-specific” or from “shared” factors, which implies a mechanism-specific set of prices, quantities and rents. We discuss and extend these characterizations, notably in relation to the real-world characterization of water as a factor (for which we use the terms technology specific, fully shared and “mixed”). We propose that the presence of these separate mechanisms results in the models being sensitive to relatively small variations in specific numerical values. To address this sensitivity, we suggest a specific role for specific (sub)models or key choices to counter unrealistic model outcomes. To support our proposal we present a selection of simulations for aggregated world regions, and show how key results concerning quantities, prices and rents can be subject to considerable change depending on the precise definitions of resource endowments and the technology-specificity of the factors. For instance, depending on the adopted water heterogeneity level, outcomes can vary from relatively low-cost solutions to higher cost ones and can even reach infeasibility. In the main model discussed here (WTM) factor prices are exogenous, which also contributes to the overall numerical sensitivity of the model. All this affects to a large extent our interpretation of the water challenges, which preferably need to be assessed in integrated frameworks, to account for the main socioeconomic variables, technologies and resources.


Author(s):  
Dorota Zając ◽  
Dariusz Przybylski ◽  
Jadwiga Sołoducho

AbstractDeveloping effective and low‐cost organic semiconductors is an opportunity for the development of organic solar cells (OPV). Herein, we report the molecular design, synthesis and characterization of two molecules with D–A–D–A configuration: 2-cyano-3-(5-(8-(3,4-ethylenodioxythiophen-5-yl)-2,3-diphenylquinoxalin-5-yl)thiophen-2-yl)acrylic acid (6) and 2-cyano-3-(5-(2,3-diphenyl-8-(thiophen-2-yl)quinoxalin-5-yl)thiophen-2-yl)acrylic acid (7). Moreover, we investigated the structural, theoretical and optical properties. The distribution of HOMO/LUMO orbitals and the values of the ionization potential indicate good semiconducting properties of the compounds and that they can be a bipolar material. Also, the optical study show good absorption in visible light (λabs 380–550 nm). We investigate the theoretical optoelectronic properties of obtained compounds as potential materials for solar cells.


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