توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱Dynamic Analysis of High Speed Spindles Based on a Simplified Model for Angular Contact Bearings
نویسنده(ها): ، ،
اطلاعات انتشار: دومین کنفرانس بین المللی و هشتمین کنفرانس ملی مهندسی ساخت و تولید، سال
تعداد صفحات: ۱۰
Accurate and realistic modeling of high speed spindles is essential for design of precision high speed machine tools. The bearings play an essential role in the dynamic performance of the spindles and their behavior is usually nonlinear. In this work, a five DOF simplified model for angular contact ball bearings is presented which takes into account the effects of high speed rotation on variation of the contact angles of the inner and the outer rings of the bearing. The model uses an average contact angle calculated at each rotational speed. It is shown that considering the changes in contact angles has a small effect on dynamic behavior of the bearing for typical range of spindle speeds currently available on most high speed machine tools. Therefore, the presented model can be safely used for modeling of the spindle bearings in such spindles with reasonable accuracy and reduced computational cost.<\div>

۲The Study of Improvement of Dispersive Soil Using Magnetic Field
نویسنده(ها): ، ، ،
اطلاعات انتشار: Journal of the Structural Engineering and Geotechnics، دوم،شماره۱، ۲۰۱۲، سال
تعداد صفحات: ۶
In this study, the feasibility of using magnetic technology to reduce the dispersion of soil has been investigated. The reference treatment was potable water and 3 magnetic water devices (with different magnetic intensities) were used for magnetizing the potable water. The results showed that the magnetic field has a significant effect in order of 5 percent on increasing of magnesium concentration in soil columns and the calcium concentration in magnetic treatment was more than the reference treatment. It seemed that improving in hydrogen bonding between water molecules and clay particles and water trapping in soil caused reduction of salt in the soil. According to the increase of calcium and magnesium bivalent Cations in the soil, it is suggested that the use of magnetic field could improve soil’s dispersion and decrease the degree of soil’s dispersion.
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