Axiomatic design of a manually powered wheelchair lift mechanism

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007.Includes bibliographical references (leaves 65-66).The objective of this research is to create an inexpensive mechanism which gives wheelchair users the ability to adjust the vertical height of their chair while seated. There are currently 1.5 million manual wheelchair users in the United States. However, no manual height adjust mechanisms are available in the current marketplace. Increased vertical range of sight and reach will result in unprecedented levels of independence for wheelchair users. We applied the theory of axiomatic design as a methodology for designing a mechanism to fill this compelling unmet need. Careful consideration of the functional and physical domains guided us to an effective solution to this design problem. A proof of concept prototype was created to demonstrate the potential of this design solution. This prototype is capable of lifting a person of 2501bs weight 15 inches off of the ground while seated in the wheelchair. This design solution is viable, and with continued work we hope that it may someday come to fruition as an effective and useful product.by Kevin DiGenova and Chris Coleman.S.B

Magnetic quantum phase transition in an anisotropic Kondo lattice

The quantum phase transition between paramagnetic and antiferromagnetic phases of the Kondo lattice model with Ising anisotropy in the intersite exchange is studied within the framework of extended dynamical mean-field theory. Nonperturbative numerical solutions at zero temperature point to a continuous transition for both two- and three-dimensional magnetism. In the former case, the transition is associated with critical local physics, characterized by a vanishing Kondo scale and by an anomalous exponent in the dynamics close in value to that measured in heavy-fermion CeCu_{5.9}Au_{0.1}.Comment: 4 pages, 3 figures. Version published in Phys. Rev. Let

Physico-chemical properties of ionic-liquid water mixtures

In order for Ionic Liquids (ILs) to be utilized to their full potential, it is necessary to have a complete understanding of their physical properties, including phase transitions temperatures1. We have previously reported into the extent of structuring of ILs using photochromic molecular probes, and investigated the appropriate IL water content to yield hydrated IL systems for analysis of polarity and to create environments suitable for effective enzyme activity 1,2,3. In this study we investigated interactions in hydrated ILs containing variable hydrophobic and hydrophilic regions through optical and thermal analysis. The enthalpies and phase transitions of the systems were compared, between the temperature range -50°C to +30°C for the ILs with varying degrees of hydration. Reichardtʼs dye was used as a molecular probe to monitor changes in interactions in the ILs as a function of temperature. Comparisons were made between ILs and for ILs with varying degrees of hydration. Spectroscopic studies were performed using Perkin Elmer UV-Visible Spectrometer and phase transitions monitored using a Perkin Elmer Differential Scanning Calorimeter. The ILs examined are; Trihexyltetradecylphosphonium Chloride [P6,6,6,14 Cl] Tributyl-tetradecylphosphonium Chloride, [P4,4,4,14 Cl], 1-Ethyl-methyl-3-imidazolium-ethyl Sulfate [Emim][EtSO4] and Trihexyltetradecylphosphonium Dicyanamide [P6,6,6,14 DCA]. 1. Robert Byrne, Simon Coleman, Simon Gallagher, and Dermot Diamond. Designer Molecular Probes for Phosphonium Ionic Liquids. Physical Chemistry Chemical Physics, 2010. 2. Kyoko Fujita, Douglas R. MacFarlane, Maria Forsyth, Masahiro Yoshizawa-Fujita, Kenichi Murata,† Nobuhumi Nakamura, and Hiroyuki Ohno*,Solubility and Stability of Cytochrome c in Hydrated Ionic Liquids: Effect of Oxo Acid Residues and Kosmotropicity, 2007. 3. SergeiV.DzyubaandRichardA.Bartsch,Expandingthepolarityrange of ionic liquids, Tetrehedron Letters, 2002

Quantum Critical Behavior in Kondo Systems

This article briefly reviews three topics related to the quantum critical behavior of certain heavy-fermion systems. First, we summarize an extended dynamical mean-field theory for the Kondo lattice, which treats on an equal footing the quantum fluctuations associated with the Kondo and RKKY couplings. The dynamical mean-field equations describe an effective Kondo impurity model with an additional coupling to vector bosons. Two types of quantum phase transition appear to be possible within this approach---the first a conventional spin-density-wave transition, the second driven by local physics. For the second type of transition to be realized, the effective impurity model must have a quantum critical point exhibiting an anomalous local spin susceptibility. In the second part of the paper, such a critical point is shown to occur in two variants of the Kondo impurity problem. Finally, we propose an operational test for the existence of quantum critical behavior driven by local physics. Neutron scattering results suggest that CeCu$_{6-x}$Au$_x$ passes this test.Comment: 6 pages, 4 eps figures, REVTeX (epsf style

Building a Multicultural Competent Counseling Approach Focused on Advocacy for Gifted and Talented Students

The Illinois Mathematics and Science Academy (IMSA) counseling department strives to support and advocate for students of all cultural backgrounds and financial means. The counselors aspire to meet or exceed multicultural competencies established when working with gifted and talented students. Current competency based counseling models address multicultural concepts but do not integrate updated framework to include social justice advocacy. Utilizing the United Nations’ sustainable goal of reducing inequality as the catalyst for this presentation, our focus will explore current research around competently counseling gifted and talented students in a multicultural fashion, and weaving newly developed advocacy based framework

EXPLORING THE ANTECEDENTS TO INFORMATION SYSTEMS DISCONTINUITIES: A COMPARISON OF THREE CASE STUDIES

An unanswered question in information systems (IS) research is: What triggers organizations to undertake reengineering or replacement of a mission-critical information system? While the benefits of reengineering efforts and new system implementations are well-documented, these large scale discontinuous system-changes are costly and known to be risky. IS projects frequently fail. A great deal of research has focused on understanding how new system implementations can be successful, once the decision to move forward is made. Alternatively, this research examines the antecedents of undertaking that costly and risky discontinuous change, as well as the role of inertia that precipitates the undertaking. We conducted 37 semistructured interviews in three organizations. We explored the reasons for replacing or reengineering their mission-critical information systems. We employ three theoretical explanations of change as derived from the organization theory and strategy literatures to conduct a cross-case analysis. While in some case studies external environmental forces and internal strategy changes reveal themselves as antecedents, we found that across all three cases, inherent constraints in the system slowed and even stifled the adaptation and design of these systems. We draw on structural inertia organizational change theories to explain these antecedents and how the systems evolved into their current states

Negotiating the Sacred

Religion; Sociology; Blasphemy; Sacrilege; Offenses against religio

An electromyographic comparison of neck conditioning exercises in healthy controls

The purpose of this study was to compare surface electromyography (EMG) activation levels of selected neck muscles for two common neck-training modalities (Thera-Band and Cybex). Seventeen asymptomatic subjects (eight men and nine women) with a mean age 23.4 years were recruited. EMG activation normalized to maximal voluntary isometric contraction (MVIC) was measured with subjects performing exercises with green, blue, and black Thera-Bands and 50%, 70%, and 90% of 3RM for the Cybex modality. Four variables were used to depict exercise intensity: average and peak EMG activation in the concentric and eccentric phases. Significant differences (P &lt;= 0.05) in EMG activation were evident when comparing intensities of the Cybex modality with each other and when comparing the Cybex intensities with Thera-Band intensities in most cases. Minimal differences were found among differing intensities of Thera-Band. Thera-Band exercise resulted in low-level EMG activation (range, flexion 3.8-15.7% MVIC; range, extension 20.2-34.8% MVIC); therefore, such exercise may be useful in rehabilitation programs. Cybex exercise (range, flexion 20.9-83.5% MVIC; range, extension 40.6-95.8% MVIC) may be useful for occupation-related injury prevention. However, exercise prescription should be undertaken with care as the mechanical loading on passive spinal structures is unknown.<br /