94 research outputs found
A 2D description of the single crystal thin plate growth from the melt by micro- pulling- down method. Part 2
No full textThis paper is the second part of a 2D description of a single crystal thin plate growth by micro-pulling–down (μ-PD) method. This part concerns the following aspects: temperature distribution and melt flow in the melt–crystal system (section 2); impurity distribution (section 3). Numerical illustration concerning the above aspects are given for the growth of a thin Si plate of 0.0001 [m] by using COMSOL Multiphysics software. The advantage of this description is that it helps in the better understanding of the impurity dispersion in meniscus and may help the
improvement of crystal quality
A 2D description of the single crystal thin plate growth from the melt by micro - pulling - down method. Part 1
No full textThis paper is the first part of a 2D description of a single crystal thin plate growth by micro-pulling–down (μ-PD) method. This part concerns the following aspects: the free surface equation and the pressure difference across the free surface (section 2); limits of the pressure difference p across the free surface (section 3); static stability of the free surface (section 4); the plate half thickness change rate due to the change of the pressure difference p across the free surface and the half half-thickness control (section 5).
Numerical illustrations of the above aspects is given in case of a Si thin plate of 0.0001 [m] by using the Maple 17 software.
The advantage of this description is that it helps to better understand the dependence of the meniscus free surface shape and size on the pressure difference across the meniscus free surface and may help the automation of manufacturing
Balint seminars: The transatlantic experience through videoconference
No full textIntroduction: The Balint seminar is used in many family medicine residencies to improve and strengthen the patient-doctor relationship: to make better doctors. Given the lack of Balint leaders in developing countries, the family medicine department at the American University of Beirut (AUB) decided to collaborate with the Medical University of South Carolina (MUSC)-with more than 30 years of experience-to start Balint seminars through videoconferencing. Objective: Evaluate the feasibility and effectiveness of Balint seminars conducted through videoconference. Methods: A qualitative research using focus group and leaders' feedback to evaluate feasibility of delivery of Balint seminars through videoconference. A Polycom videoconference was set up between residents at AUB and two credentialed Balint leaders at MUSC. The videoconference was composed of two parts: (i) MUSC faculty facilitating Balint seminars; and (ii) MUSC and AUB faculty debriefing following each Balint session. Results: Twenty-six videoconferences were conducted from 15 February 2013 to 31 March 2014. Four themes emerged: technology and connectivity issues, administrative issues, coordination among different time zones and cultural/contextual issues. The videoconferencing with family medicine residents at AUB seemed quite natural and very familiar to the Balint leaders at MUSC. The seminars encouraged the residents to see things from the patients' perspective, inspiring new thoughts and ideas on how to deal with troubling patients. Conclusion: Videoconference Balint seminars offer a promising way to extend the activity to health care providers in other disciplines, states and countries. Moreover, this format has the potential to increase the number of trained Balint leaders. © The Author 2014. Published by Oxford University Press. All rights reserved
The effect of the pressure difference across the free surface in case of a NdYAG micro fiber growth by the micro-pulling-down process
No full textDoctors at times of national instability: What Balint seminars reveal
No full textBackground: It is not known in what ways is the doctor whose practice is secure in a clinic challenged to maintain a therapeutic doctor–patient relationship when confronting a flood of immigrants within a country that is politically volatile, internally fractionalized, and surrounded by sporadic military incursions? Methods: During Balint seminars, a family medicine resident presents a troubling case which all group members reflect upon from the perspective of the doctor, the patient, and their relationship. Balint leaders later debrief and review the work of the group. Lebanon has passed through many political, social, and religious conflicts and was affected by the onset of the Syrian Civil War in 2010. The Balint leaders had begun to see in resident case presentations reflections of war’s disruption of the doctor–patient relationship. Two Balint leaders reviewed a log of all the cases between 2013 and 2016. Results: In our observations, the discussion of the presented cases mirrored the cultural, social, religious, and political context of the country. First, the political situation was reflected in the dynamics of the group: agitation, conflicts, hopelessness, and a search for norms. Second, the residents subconsciously chose words in their discussion that reflect the country’s situation. Third, the presented case was stirred by a tragic war-related event. Conclusions: The social/political/religious context in which the physician is practicing distracts the doctor from fulfilling his/her professional role. Balint seminars are an example of direct, experiential learning that provide an excellent opportunity for the special training of primary care physicians who deal with refugees and citizens to self-reflect on war’s impact on them and their profession. © The Author(s) 2018
Existence and stability of a capillary free surface appearing in dewetted Bridgman process. I.
No full text
Global and local stability and instability of the constant spatially developing gas flow
No full textIn this paper different types of stabilities (global, local) with respect to instantaneous perturbations and permanent source produced time harmonic perturbations are presented in case of a
spatially developing gas flow. Some types of instabilities (global absolute, local convective) are also presented. For this purpose the Euler equations linearized at the constant gas flow are used. It is shown for instance, that the constant gas flow is global absolutely unstable with respect to some instantaneous and some permanent source produced time harmonic perturbations. The locally convective instability is also proven with respect to some instantaneous and permanent source produced time harmonic perturbations
Existence and Stability of the Solution of a Nonlinear Boundary Value Problem
No full textThe purpose is to find conditions assuring the existence of solutions for a nonlinear, boundary value problem in case of the axis-symmetric Young-Laplace differential equation. The equation describes the capillary surface between two static fluids. Necessary or sufficient conditions are found for the existence of a solution. The static stability of the obtained solution is also analyzed and stability or instability results are revealed. For the NdYAG microfiber growth, by the pulling-down method, numerical illustrations are given
Numerical illustration of the global and local stability and instability of the constant spatially developing 1D gas flow
No full textIn this paper different types of stabilities (global, local) with respect to instantaneous perturbations and permanent source produced time harmonic perturbations are numerically
illustrated in case of a constant spatially developing 1D gas flow. Some types of instabilities (global absolute, local convective) are also illustrated. For this purpose the 1D Euler equations linearized at the constant gas flow are used. It is illustrated for instance, that the constant gas flow is globally absolutely unstable with respect to some instantaneous and some permanent source produced time harmonic perturbations. The locally convective instability is also illustrated with respect to some instantaneous and some permanent source produced time harmonic perturbations
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