Social Media: Revolutionizing the Business World

Public communication avenues were greatly affected through the invention of the Internet; however, what has developed communication processes even further is the rise of social media. This thesis explains how the utilization of social media tools is revolutionizing the business world and also provides information to understand the direction in which social media is heading

Thermophysical and Thermochemical Property Measurement and Prediction of Liquid Metal Titanium Alloys with Applications in Additive Manufacturing

Accurate high-temperature thermophysical property data for liquid metals and alloys are important for simulation of laser-based 3D printing processes. To understand and better control such additive manufacturing processes, knowledge of density, viscosity, and surface tension of liquid metals and alloys versus composition and temperature is needed. Likewise, thermochemical property data information regarding alloys, including chemical activities and free energies relative to composition and temperature, aid in the understanding and development of phase data important in the material design process. Vacuum electrostatic levitation (ESL) is an important technique through which both thermophysical and thermochemical property measurements can be accomplished without physical contact with the liquid. We performed ESL measurements on molten Ti-based alloys, including elemental Ti, Ti-xAl binaries (x = 0-10 percent weight), Ti-6Al-4V, and Ti-6Al-4V-10Mo, through a container-less oscillating drop technique at the NASA Marshall Space Flight Center. Ti-Al-V-Mo quaternary alloy was studied for laser-based 3D printing, and showed improved mechanical properties over traditional β Ti alloys. Results for elemental Ti, Ti-xAl, and Ti-6Al-4V are compared with previously published results, while those for Ti-6Al-4V-10Mo are reported here for the first time. Additional thermodynamic data are generated for binary Ti-Al, and compared to CALPHAD results while viscosity and density values of liquid titanium were calculated via molecular dynamics and compared to experimental values. The test and simulation procedure developed provides a framework for the development of new and higher-order alloys in the high temperature regime and in the liquid phase

Fractional Super Lie Algebras and Groups

n^{th} root of a Lie algebra and its dual (that is fractional supergroup) based on the permutation group $S_n$ invariant forms are formulated in the Hopf algebra formalism. Detailed discussion of $S_3$-graided $sl(2)$ algebras is done.Comment: 13 pages, detailed discussion of $S_3$-graided $sl(2)$ is adde

Flexible rod design for educational wind balance

This is a copy of the author 's preprint version of an article published in the journal Experimental techniques. The final publication is available at Springer via http://dx.doi.org/10.1007/s40799-016-0017-9This article provides a technical description of a flexible hinge for wind tunnel rigs. For academic purposes, the device was integrated into several rod flexures to build a home-made external wind balance system. The cylindrical elastic element incorporates several notches, and the flexure linkage is able to transmit force in the main axial direction without hindering perpendicular movement. The flexural element described here is simple and easily manufactured, and can also be used with other types of wind balance. The flexure described in this article has similar functionality to those mentioned in the reference section, but has a more compact element. The project's effectiveness was demonstrated in a series of experimental comparisons of forces and moments measured on a wing using the N.A.C.A. Clark-Y airfoil profile.Preprin

Estimation of wall shear stress using 4D flow cardiovascular MRI and computational fluid dynamics

Electronic version of an article published as Journal of mechanics in medicine and biology, 0, 1750046 (2016), 16 pages. DOI:10.1142/S0219519417500464 © World Scientific Publishing CompanyIn the last few years, wall shear stress (WSS) has arisen as a new diagnostic indicator in patients with arterial disease. There is a substantial evidence that the WSS plays a significant role, together with hemodynamic indicators, in initiation and progression of the vascular diseases. Estimation of WSS values, therefore, may be of clinical significance and the methods employed for its measurement are crucial for clinical community. Recently, four-dimensional (4D) flow cardiovascular magnetic resonance (CMR) has been widely used in a number of applications for visualization and quantification of blood flow, and although the sensitivity to blood flow measurement has increased, it is not yet able to provide an accurate three-dimensional (3D) WSS distribution. The aim of this work is to evaluate the aortic blood flow features and the associated WSS by the combination of 4D flow cardiovascular magnetic resonance (4D CMR) and computational fluid dynamics technique. In particular, in this work, we used the 4D CMR to obtain the spatial domain and the boundary conditions needed to estimate the WSS within the entire thoracic aorta using computational fluid dynamics. Similar WSS distributions were found for cases simulated. A sensitivity analysis was done to check the accuracy of the method. 4D CMR begins to be a reliable tool to estimate the WSS within the entire thoracic aorta using computational fluid dynamics. The combination of both techniques may provide the ideal tool to help tackle these and other problems related to wall shear estimation.Peer ReviewedPostprint (author's final draft

Resiliencia familiar y el énfasis en los recursos del sistema

En este artículo, las reflexiones como investigadora sobre la capacidad de sacar un individuo de eventos adversos ha despertado el interés por revisar bibliografía e investigaciones para buscar unas respuestas aproximadas a la pregunta: ¿Por qué algunas personas pueden mantener o lograr una trayectoria de desarrollo positiva en circunstancias que muchos otros viviendo acontecimientos similares no lo logran? En otras palabras, ¿De dónde proviene la resiliencia individual? Se identifican factores protectores a nivel individual y se avanza en estudiar en el contexto cercano al individuo, es decir la familia, los aspectos que contribuyen a fomentar la resiliencia familiar y un análisis de ésta, desde el enfoque sistémico

Family resilience and the emphasis on system resources

En este artículo, las reflexiones como investigadora sobre la capacidad de sacar un individuo de eventos adversos ha despertado el interés por revisar bibliografía e investigaciones para buscar unas respuestas aproximadas a la pregunta: ¿Por qué algunas personas pueden mantener o lograr una trayectoria de desarrollo positiva en circunstancias que muchos otros viviendo acontecimientos similares no lo logran? En otras palabras, ¿De dónde proviene la resiliencia individual? Se identifican factores protectores a nivel individual y se avanza en estudiar en el contexto cercano al individuo, es decir la familia, los aspectos que contribuyen a fomentar la resiliencia familiar y un análisis de ésta, desde el enfoque sistémico.In this article, reflections as a researcher on the ability to remove an individual from adverse events has aroused interest in reviewing literature and research to find approximate answers to the question: Why some people can maintain or achieve a positive development trajectory in circumstances that many others living similar events do not achieve? In other words, where does individual resilience come from? Protective factors are identified at the individual level and progress is made in studying in the context close to the individual, that is, the family, the aspects that contribute to fostering family resilience and an analysis of this, from the systemic approach

Promoting lab engagement in experimental compressible flow modelling

The present work depicts the development of an experimental equipment that reveals compressible fluid dynamics, while collecting data from an incompressible flow like water in an open-channel. It consists of an extensive theoretical framework followed by a practical analysis, the aim of which was to trigger the hydraulic jump, both normal and oblique, in order to illustrate its hydro-gasdynamic analogy with a shock wave, occurring in supersonic compressible flows. The assembly, called “water table”, arises from the necessity of economical alternatives to expensive supersonic wind tunnels in the experimental study of compressible flows. Thus, a canal based on a Laval nozzle was constructed where water flow could experiment a hydraulic jump. Through its visual and experimental perception, fellow interested could more easily understand the physics and engineering behind this phenomenon. Multiple design alternatives were evaluated considering environmental, economic, functional and aesthetic factors. A low-cost implementation was critical in the design process. The measurements revealed that the geometry of the nozzle and the wedges designed as obstacles to cause obliquity were the most influential elements in the formation of a hydraulic jump in the set-up. Regarding the experimental variables, the upstream and downstream heights had the highest relevance. Therefore, their manipulation and analysis could lead to further educational investigations. This research is a step forward to support students in the understanding of compressible flow principles by providing an in-house experimental set-up. The equipment is an opportunity of carrying out lab measurements, which certainly guides to a major commitment in the fieldPostprint (published version

In-house low-cost water table prototype to practically analyse the modelling compressible flow in a fluid engineering course

The present work studies the hydro-gasdynamic analogy between a shock wave, occurring in supersonic internal or external compressible flows, and a hydraulic jump, a sort of normal shock occurring in open-channel flows. It consists of an extensive theoretical framework followed by a practical analysis, the aim of which was to experimentally trigger the hydraulic jump, both normal and oblique, while using a low-cost designed lab prototype. The assembly development, called ‘water table’, arises from the necessity of economical alternatives to expensive supersonic wind tunnels in the experimental study of compressible fluid dynamics. With this objective in mind, a hydraulic canal based on a Laval nozzle was constructed where water flow could accelerate from subcritical to critical to supercritical regime and then return to subcritical regime through a hydraulic jump. In addition, multiple design alternatives were evaluated considering environmental, economic, functional and aesthetics factors. A low-cost implementation was the critical criterion in the design process. The measurements have revealed that the geometry of the nozzle and the wedges designed as obstacles to cause obliquity are the most significant and influential elements in the formation of a hydraulic jump in the experimental set-up. Regarding the experimental variables, the experiments demonstrate the effect of the upstream and downstream heights of the hydraulic jump in the data collection. This experience is a step forward in supporting students in the understanding of compressible flow and its principles by providing an in-house experimental set-up that promotes active learning, motivation and interest in fluid mechanicsPostprint (author's final draft