3,206 research outputs found
Exciting Students About Materials Science and Engineering: A Project-Based, Service-Learning Museum Design Course
A new course was developed for Materials Engineering students to design, create, and install interactive, educational displays on Materials Science & Engineering for a science museum at a local K-6 charter school. The course grew out of an ASM Foundation grant “to excite young people in materials, science, and engineering careers,” and the challenge was put forth to Cal Poly students. A formal design sequence was applied to give the students the opportunity to learn about the design process, project management, and teamwork. User profiles were created for the stakeholders, and project values were established. The class partnered with the museum curator to develop functional and design requirements for the displays, and to gain valuable feedback during the project development. Guest lectures and discussions with museum exhibit developers, education specialists, and design experts assisted the class. Three different displays that highlighted materials were developed: “Metallic Trampoline” (amorphous metal), “Smart Materials” (NiTi shape memory alloys), and “Touch and See” (heat sensing liquid crystals). The final museum displays were well received by the client and end users. A survey at the end of the quarter revealed that the engineering students gained valuable design and project experiences
Compositional influences on the microstructures, phase stability, and mechanical properties of TiCrâ‚‚ laves phase alloys
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1996.Includes bibliographical references.by Katherine C. Chen.Ph.D
Assessment of the Compositional Influences on the Toughness of TiCr\u3csub\u3e2\u3c/sub\u3e-Base Laves Phase Alloys
Systematic studies of alloys based on TiCr, have been performed in order to improve the toughness of Laves phase intermetallics. The extent to which alloy compositions and annealing treatments influence the toughness was quantified by Vickers indentation. The single-phase Laves behavior was first established by studying stoichiometric and nonstoichiometric TiCr,. Next, alloying effects were investigated with ternary Laves phases based on TiCr2. Different microstructures of two-phase alloys consisting of (Ti,Cr)-bcc+TiCr2, were also examined. Various toughening theories based on vacancies, site-substitutions, crystal structure (C14, C36, or Cl5) stabilization, and the presence of a second phase were evaluated. The most effective factors improving the toughness of TiCr2, were determined, and toughening mechanisms are suggested
Curricula to Educate the 2020 MSE Engineering Professional: Simple But Powerful Changes in the Way that MSE is Taught
National leaders in science and technology sectors speak in unison as they call for engineers who are not only technically competent in their fields, but who possess the abilities to communicate well, to work on teams, to apply systems thinking, to operate in the global business environment, to design within a greater set of constraints (environmental, health and safety, sustainability, economic, societal, political, manufacturability, and ethical). In short, our challenge is to educate an engineering professional who is far more sophisticated than the engineer of the 20th century. Additionally, challenges brought on by the overuse of natural resources put a special responsibility on materials science and engineering (MSE) faculty, whose role it is to assist in shaping the MSE profession. How can faculty deliver relevant curricula for the MSE engineering professional in an already crowded curriculum? Certainly curricular content must be up-to-date. However, a number of the goals can be met through changing the way in which the curriculum is delivered. In particular, we have emphasized mastery at the lower levels to increase retention, and implemented a number of learning “best practices”. Our preliminary results are promising: within one year, we were able to reverse a five-year trend in declining enrollment; we have just finished our fourth consecutive year of 100% on-time completions of senior projects; students exhibit a shift in mindset towards a greater awareness of their professional responsibility to serve humanity. In this paper, we will provide a survey of the techniques that we have used along with some preliminary results from our program
Effects of Hydrogen on the Phases and Transition Temperatures of NiTi
Austenitic (B2) NiTi samples were cathodically charged with various amounts of hydrogen. Trends are tracked based on temperature, time and voltage throughout the process to establish consistent and predictive hydrogen charging procedures. The effect of hydrogen on the austenitic structure and the formation of hydrides are studied with x-ray diffraction (XRD). An increase in the austenite lattice parameter with increased hydrogen content is observed up to a hydrogen solubility limit of approximately 85 wppm. At greater hydrogen concentrations, additional XRD peaks appear, suggesting possible hydride formation. Differential scanning calorimetry (DSC) results show a decrease in both the austenitic and martensitic transition temperatures with increased atomic hydrogen content and increased hydride phase. Scanning electron microscopy (SEM) is used to reveal the hydride phase. The effect of atomic hydrogen on NiTi and the structure of the hydride phase are compared with previous hydrogen studies
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IL-17A produced by αβ T cells drives airway hyper-responsiveness in mice and enhances mouse and human airway smooth muscle contraction.
Emerging evidence suggests that the T helper 17 (T(H)17) subset of αβ T cells contributes to the development of allergic asthma. In this study, we found that mice lacking the αvβ8 integrin on dendritic cells did not generate T(H)17 cells in the lung and were protected from airway hyper-responsiveness in response to house dust mite and ovalbumin sensitization and challenge. Because loss of T(H)17 cells inhibited airway narrowing without any obvious effects on airway inflammation or epithelial morphology, we examined the direct effects of T(H)17 cytokines on mouse and human airway smooth muscle function. Interleukin-17A (IL-17A), but not IL-17F or IL-22, enhanced contractile force generation of airway smooth muscle through an IL-17 receptor A (IL-17RA)-IL-17RC, nuclear factor κ light-chain enhancer of activated B cells (NF-κB)-ras homolog gene family, member A (RhoA)-Rho-associated coiled-coil containing protein kinase 2 (ROCK2) signaling cascade. Mice lacking integrin αvβ8 on dendritic cells showed impaired activation of this pathway after ovalbumin sensitization and challenge, and the diminished contraction of the tracheal rings in these mice was reversed by IL-17A. These data indicate that the IL-17A produced by T(H)17 cells contributes to allergen-induced airway hyper-responsiveness through direct effects on airway smooth muscle
The Foundation Series on Corrosion: Integrating Science, Math, Engineering & Technology in a Lab Setting
We have developed a laboratory module focusing on the subject of corrosion. The module itself is designed to be completed in one three-hour session. It consists of three parts: I. The Impact of Corrosion Media, II. The Impact of Corroding Materials, III. The Impact of Anode/Cathode Sizes. Our objectives in developing this module were to address the need for clear bridges between math, science and technology in the engineering curriculum and to provide a means of faculty development primarily at community colleges. As a result, it was designed to allow the engineering student to experience the synergy of science, math and engineering technology in a laboratory setting. Recent findings in learning theory research were used in the design of the module to reach students of diverse learning styles. Our targeted audience is sophomore engineering majors at community colleges and institutions without Materials Science and Engineering programs. In this paper we will present the module, its goals, objectives and performance criteria, and the preliminary results of its implementation
Phase Changes in Ni-Ti Under Laser Shock Loading
Near-equiatomic Ni-Ti, known for its shape memory behavior, can decompose to martensitic phases and/or second phase compounds. This phase competition is investigated in NixTi100-x (494Ti3 but no martensite in the AQ state, consistent with resistivity and dilatometry results which showed no hysteresis indicative of first order phase changes over 1.9 K4Ti3 amounts (present in the AQ state) did change upon loading, indicating the importance of shock-induced heating. A thermodynamically complete equation of state (EOS) for NiTi in its B2 (CsCl) structure was generated by ab initio quantum mechanical calculations. This was tested by performing laser-launched flyer experiments, which showed consistency with the theoretical EOS, validating its use in the prediction of dynamic loading histories in the samples during direct drive loading
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