EVALUATION OF GEOMETRIC SCALE EFFECTS FOR SCRAMJET ISOLATORS

A numerical analysis was conducted to study the effects of geometrically scaling scramjet inlet-combustor isolators. Three-dimensional fully viscous numerical simulation of the flow inside constant area rectangular ducts, with a downstream back pressure condition, was analyzed using the SolidWorks Flow Simulation software. The baseline, or 1X, isolator configuration has a 1” x 2.67” cross section and 20” length. This baseline configuration was scaled up based on the 1X configuration mass flow to 10X and 100X configurations, with ten and one hundred times the mass flow rate, respectively. The isolator aspect ratio of 2.67 was held constant for all configurations. To provide for code validation, the Flow Simulation program was first used to analyze a converging-diverging channel and a wind tunnel nozzle. The channel case was compared with analytical theory and showed good agreement. The nozzle case was compared with AFRL experimental data and showed good agreement with the entrance and exit conditions (Pi0= 40 psia, Ti0= 530ºR, Pe= 18.86 psia, Te= 456ºR, respectively). While the boundary layer thickness remained constant, the boundary layer thickness with respect to the isolator height decreased as the scale increased. For all the isolator simulations, a shock train was expected to form inside the duct. However, the flow simulation failed to generate this flow pattern, due to improper sizing of the isolator and combustor for a 3-D model or having a low pressure ratio of 2.38. Instead, a single normal shock wave was established at the same relative location within the length of each duct, approximately 80% of the duct length from the isolator entrance. The shape of the shock changed as the scale increased from a normal shock wave, to a bifurcated shock wave, and to a normal shock train, respectively for the 1X, 10X, and 100X models

Rules of origin for preferential trading arrangements : implications for the ASEAN Free Trade Area of EU and U.S. experience

With free trade areas (FTAs) undernegotiation between Japan and the ASEAN Free Trade Area (AFTA) members and between the Republic of Korea and AFTA members, preferential market access will become more important in Asian regionalism. Protectionist pressures will likely increase through rules of origin, the natural outlet for these pressures. Based on the experience of the European Union and the United States with rules of origin, the authors argue that, should these FTAs follow in the footsteps of the EU and the U.S. and adopt similar rules of origin, trading partners in the region would incur unnecessary costs. Using EU trade under the Generalized System of Preferences with Africa, Caribbean, and Pacific partners, the authors estimate how the use of preferences would likely change if AFTA were to veer away from its current uniform rules of origin requiring a 40 percent local content rate. Depending on the sample used, a 10 percentage point reduction in the local value content requirement is estimated to increase the utilization rate of preferences by between 2.5 and 8.2 percentage points.Free Trade,Rules of Origin,Trade and Regional Integration,Economic Theory&Research,Trade Policy

Care-Teach: Proposing an Open-Source Approach to Personalized Learning

Care-Teach is an algorithmic educational model that provides teachers and educators with the tools to create interactive, text-based lessons that address a student’s need for continuity and reinforcement. Care-Teach is built around two core components: a Student Behavior Profile and the Skill Tree. These models work together to give each student a personalized learning experience that reinforces their pre-existing strengths and inclinations. The Student Behavior Profile model keeps track of a learner’s inclinations and mood, utilizing metrics such as average response time and accuracy to categorize opportunities for educator involvement. The Skill Tree is an organizational model that guides progress through learning objectives. Each activity is linked to an expected set of skills, and each skill is descended from a core axiom, allowing one to draw a clear line from a lesson to the most basic concept needed to understand it. Informed by the Student Behavior Profile, one can serve up activities and axioms from previous lessons to promote a holistic understanding of the subject with each assignment. The Care-Teach system provides a versatile foundation for the development of open-source companion apps, which will assist educators in enriching their programs in both online and traditional teaching situations

How Much Market Access in FTAs? Textiles Under NAFTA

This paper estimates the effective market-access granted under NAFTA in textiles and apparel by combining two approaches. First, we estimate the effect of tariff preferences and rules of origin on the border prices of Mexican final goods exported to the US and of US intermediates exported to Mexico.NAFTA, Rules of Origin, regional integration

How Much Market Access in FTAs? Textiles Under NAFTA

This paper estimates the effective market-access granted under NAFTA in textiles and apparel by combining two approaches. First, we estimate the effect of tariff preferences and rules of origin on the border prices of Mexican final goods exported to the US and of US intermediates exported to Mexico.NAFTA;Rules of Origin;regional integration

Phase-field Dislocation Dynamics Code Optimization

The importance of the study of nanocrystalline materials has gained a huge amount of attention these years due to its extraordinary mechanical, electrical and chemical properties. One significant way to progress in this field is by simulating the behavior of the particles in nano scale, which is not only a need but a challenge due to massive interactions that occur there. The phase-field dislocation dynamics (PFDD) method has been successfully employed in the modeling of plastic deformation, creep and grain boundary sliding. In PFDD, the plastic strain and the energy are functions of phase fields that obey a set of complex equations. In the algorithm approach this complexity increases depending on different factors that, in the end, increase the time and computational resource used, which this research pretend optimize. Even though Fast Fourier Transformation and MPI have been utilized in the PFDD code due to his optimal approach and matricial representation which makes the algorithms more understandable the efficiency is still a major concern in matters of computational time and resource consumption. This research intends to give an improvement to the programs that simulates the nanocrystalline materials and the models that follows the dynamics locations so outgoing researchers can use it in a more efficient way. The result will be a improved program that follows the PFDD models and simulates the nanocrystalline behavior with different materials and different constraints in the environment as in the materials itselfs with a more friendly and intelligent input for the user

Commercial polycarbonate track-etched membranes as substrates for low-cost optical sensors

[EN] Porous materials have become one of the best options for the development of optical sensors, since they maximize the interaction between the optical field and the target substances, which boosts the sensitivity. In this work, we propose the use of a readily available mesoporous material for the development of such sensors: commercial polycarbonate track-etched membranes. In order to demonstrate their utility for this purpose, we firstly characterized their optical response in the near-infrared range. This response is an interference fringe pattern, characteristic of a Fabry¿Pérot interferometer, which is an optical device typically used for sensing purposes. Afterwards, several refractive index sensing experiments were performed by placing different concentrations of ethanol solution on the polycarbonate track-etched membranes. As a result, a sensitivity value of around 56 nm/RIU was obtained and the reusability of the substrate was demonstrated. These results pave the way for the development of optical porous sensors with such easily available mesoporous material.This research was funded by the Spanish Government through grant TEC2015-63838-C3-1-R-OPTONANOSENS and the Universitat Politecnica de Valencia through grants PAID-01-17.Martinez-Perez, P.; García-Rupérez, J. (2019). Commercial polycarbonate track-etched membranes as substrates for low-cost optical sensors. Beilstein Journal of Nanotechnology. 10:677-683. https://doi.org/10.3762/bjnano.10.6767768310Ruiz-Tórtola, Á., Prats-Quílez, F., González-Lucas, D., Bañuls, M.-J., Maquieira, Á., Wheeler, G., … García-Rupérez, J. (2018). Experimental study of the evanescent-wave photonic sensors response in presence of molecular beacon conformational changes. Journal of Biophotonics, 11(10), e201800030. doi:10.1002/jbio.201800030Caroselli, R., Martín Sánchez, D., Ponce Alcántara, S., Prats Quilez, F., Torrijos Morán, L., & García-Rupérez, J. (2017). Real-Time and In-Flow Sensing Using a High Sensitivity Porous Silicon Microcavity-Based Sensor. Sensors, 17(12), 2813. doi:10.3390/s17122813Prabowo, B., Purwidyantri, A., & Liu, K.-C. (2018). Surface Plasmon Resonance Optical Sensor: A Review on Light Source Technology. Biosensors, 8(3), 80. doi:10.3390/bios8030080Levitsky, I. (2015). Porous Silicon Structures as Optical Gas Sensors. Sensors, 15(8), 19968-19991. doi:10.3390/s150819968Ponce-Alcántara, S., Martín-Sánchez, D., Pérez-Márquez, A., Maudes, J., Murillo, N., & García-Rupérez, J. (2018). Optical sensors based on polymeric nanofibers layers created by electrospinning. Optical Materials Express, 8(10), 3163. doi:10.1364/ome.8.003163Qiu, H.-J., Li, X., Xu, H.-T., Zhang, H.-J., & Wang, Y. (2014). Nanoporous metal as a platform for electrochemical and optical sensing. J. Mater. Chem. C, 2(46), 9788-9799. doi:10.1039/c4tc01913jShindell, O., Mica, N., Ritzer, M., & Gordon, V. D. (2015). Specific adhesion of membranes simultaneously supports dual heterogeneities in lipids and proteins. Physical Chemistry Chemical Physics, 17(24), 15598-15607. doi:10.1039/c4cp05877aPárraga-Niño, N., Quero, S., Ventós-Alfonso, A., Uria, N., Castillo-Fernandez, O., Ezenarro, J. J., … Sabrià, M. (2018). New system for the detection of Legionella pneumophila in water samples. Talanta, 189, 324-331. doi:10.1016/j.talanta.2018.07.013Martín-Sánchez, D., Ponce-Alcántara, S., Martínez-Pérez, P., & García-Rupérez, J. (2019). Macropore Formation and Pore Morphology Characterization of Heavily Doped p-Type Porous Silicon. Journal of The Electrochemical Society, 166(2), B9-B12. doi:10.1149/2.0051902jesWilson, R. H., Nadeau, K. P., Jaworski, F. B., Tromberg, B. J., & Durkin, A. J. (2015). Review of short-wave infrared spectroscopy and imaging methods for biological tissue characterization. Journal of Biomedical Optics, 20(3), 030901. doi:10.1117/1.jbo.20.3.030901Aran, K., Sasso, L. A., Kamdar, N., & Zahn, J. D. (2010). Irreversible, direct bonding of nanoporous polymer membranes to PDMS or glass microdevices. Lab on a Chip, 10(5), 548. doi:10.1039/b924816aGarcía-Rupérez, J., Toccafondo, V., Bañuls, M. J., Castelló, J. G., Griol, A., Peransi-Llopis, S., & Maquieira, Á. (2010). Label-free antibody detection using band edge fringes in SOI planar photonic crystal waveguides in the slow-light regime. Optics Express, 18(23), 24276. doi:10.1364/oe.18.024276Sani, E., & Dell’Oro, A. (2016). Spectral optical constants of ethanol and isopropanol from ultraviolet to far infrared. Optical Materials, 60, 137-141. doi:10.1016/j.optmat.2016.06.041Ooi, C. H., Bormashenko, E., Nguyen, A. V., Evans, G. M., Dao, D. V., & Nguyen, N.-T. (2016). Evaporation of Ethanol–Water Binary Mixture Sessile Liquid Marbles. Langmuir, 32(24), 6097-6104. doi:10.1021/acs.langmuir.6b01272Ogończyk, D., Jankowski, P., & Garstecki, P. (2012). Functionalization of polycarbonate with proteins; open-tubular enzymatic microreactors. Lab on a Chip, 12(15), 2743. doi:10.1039/c2lc40204aKosobrodova, E., Jones, R. T., Kondyurin, A., Chrzanowski, W., Pigram, P. J., McKenzie, D. R., & Bilek, M. M. M. (2015). Orientation and conformation of anti-CD34 antibody immobilised on untreated and plasma treated polycarbonate. Acta Biomaterialia, 19, 128-137. doi:10.1016/j.actbio.2015.02.027Godeau, G., Amigoni, S., Darmanin, T., & Guittard, F. (2016). Post-functionalization of plasma treated polycarbonate substrates: An efficient way to hydrophobic, oleophobic plastics. Applied Surface Science, 387, 28-35. doi:10.1016/j.apsusc.2016.06.053Sultanova, N. G., Kasarova, S. N., & Nikolov, I. D. (2012). Characterization of optical properties of optical polymers. Optical and Quantum Electronics, 45(3), 221-232. doi:10.1007/s11082-012-9616-