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יוני 2018
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יוני
05
2018
אירועים בתאריך 05 ביוני 2018

סמינר המחלקה להנדסת מכונות

תאריך:5.6.2018
שעה:00:00
מיקום: 299D1
זמן תחילת האירוע: 12:50
זמן סיום האירוע: 13:40
הגוף המארגן: המחלקה להנדסת מכונות
דמי השתתפות: חינם
קהל יעד: כולם
תיאור האירוע: Industry-oriented research in polymer materials and product design: two examples יום שלישי 5.6.18 בשעה 12.50 בכיתה 299D1 Speaker: Dr. Fabian Rios, Plazit-Polygal Group ============================================================ First Example: Materials Design: Plastics have a weight advantage over metals but they lack their strength, stiffness, dimensional stability and electrical conduction. Fiber reinforced plastics have been used to bridge this properties gap, specifically engineering thermoplastics including carbon fibers (CFs). These composites are light, strong and stiff, electrostatically dissipating, and relatively easy to process by injection molding. However, the high aspect ratio and rigidity of the CFs cause orientation and anisotropy, especially when injection molded, thus reducing dimensional stability on the final product and limiting its use in precision components. In this study, hybrid polymer composite formulations of polyether imide containing CFs and carbon nanotubes (CNTs) were compounded and injection molded following a basic design of experiments (DOE) methodology. The coefficient of thermal expansion (CTE) in the polymer flow direction and perpendicular to the flow direction were used to evaluate the thermal expansion isotropy. The electrical resistivity, impact strength and morphological structure were also investigated. It was found that the addition of CNT caused a significant reduction in the thermal expansion anisotropy of the parts without compromising the impact strength. Also, it was found that CNTs are significantly more efficient than CFs for reducing the electrical resistivity. The conclusions of this study can be used to fine-tune polymer composites with high dimensional thermal stability, electrostatic dissipation and good mechanical properties, suitable for high-performance devices. Second Example: product Design The presence of weld lines can cause a significant reduction in the mechanical properties of injection molded plastic parts, especially when they contain minerals additives or fiber reinforcements, and it is a common reason for their failure. In this work a method for modifying the flow pattern in the weld line zone using a "flow disruptor" is proposed to strengthen the weld lines of fiber reinforced polypropylene. The flow disruptor is a small insert introduced inside the injection molding cavity, in the weld line area, and its objective is to mix the melt and disrupt fountain flow in order to blur and erase the weld line. The method is simple and low cost, does not require special machines or molds and does not affect the part shape or surface. Flow disruptors were designed, their effects analyzed using Moldflow® simulation, fabricated from different materials and encapsulated within injection molded tensile test samples for mechanical properties evaluation. The results of this work demonstrate that the mechanical properties in the weld line can be improved by the use of a well-designed flow disruptor, made from suitable materials. About the Lecturer: Dr. Fabian Rios is the R&D and Technical Support Manager of the Plazit-Polygal Group, a leading multinational company specializing in plastics extrusion. He is also an Adjunct Senior Lecturer at the Department of Materials Engineering, the Graduate Department of Chemical Engineering and the Graduate Interdepartmental Program in Polymer Engineering at the Technion in Haifa. Dr. Rios specializes in polymer materials and properties, polymer processing and plastics product design. The talk will be given in Hebrew
שם איש קשר: עמליה
דוא"ל: amhaim@braude.ac.il

סמינר המחלקה למתמטיקה

תאריך:5.6.2018
שעה:00:00
מיקום: EM303
זמן תחילת האירוע: 13:00
זמן סיום האירוע: 14:00
הגוף המארגן: המחלקה למתמטיקה
קהל יעד: פתוח לכולם
תיאור האירוע: Speaker: Dr. Leonid Helmer, ORT Braude College Title: Reflexivity in non-commutative Hardy Algebras' Abstract Let H∞(E) be a non-commutative Hardy algebra associated with a W∗-correspondence E. These algebras were introduced in 2004 by Muhly and Solel, and generalize the classical Hardy algebra of the unit disc H∞(D). As a special case one obtains also the algebra F∞n of Popescu, which is H∞(Cn) in our setting. In this paper we view the algebra H∞(E) as acting on a Hilbert space via an induced representation. We write it ρπ(H∞(E)) and we study the reflexivity of ρπ(H∞(E)). This question was studied by Arias and Popescu in the context of the algebra F∞n , and by other authors in several other special cases. As it will be clear from our presentation, the extension to the case of a general W∗-correspondence E over a general W∗-algebra M requires new techniques and approach. We obtain some partial results in the general case and we turn to the case of a correspondence over a factor. Under some additional assumptions on the representation : M → B(H) we show that ρπ(H∞(E)) is reflexive. Then we apply these results to analytic crossed products ρπ(H∞(αM)) and obtain their reflexivity for any automorphism α ∈ Aut(M) whenever M is a factor.
שם איש קשר: פרופ' חגי כתריאל
דוא"ל: katriel@braude.ac.il