Microcrack Growth Properties of Granite under Ultrasonic High-Frequency Excitation

Microcrack Initiation and Growth

A Monte Carlo simulation technique to predict the mean and scatter in fatigue lifetime of certain 2000 and 7000 series aluminum alloys is described. The method is based upon models of surface microcrack nucleation and early growth, which comprise the initiation phase of the fatigue failure process. The experimental basis for the models is discussed, and examples of predicted numbers and lengths...

degradation of oil impregnated paper insulation under influence of repetitive fast high voltage impulses

در طی سالهای اخیراستفاده ازمنابع انرژی تجدید پذیر در شبکه های مدرن بنا به دلایل زیست محیطی و اقتصادی به طور گسترده استفاده شده است همچون نیروگاههای بادی و خورشیدی .ولتاژتولیدی این نیروگاهها اغلب به فرم dc می باشد وادوات الکترونیک قدرت به عنوان مبدل و پل بین شکل موج dc وac استفاده می شوند.این پروسه باعث ایجاد پالسهایی برروی شکل موج خروجی می شود که می تواند وارد تجهیزات قدرت همچون ترانسفورماتور ی...

The Effect of Microcrack Dilatancy on the Permeability of Westerly Granite

Controlling plasma properties under differing degrees of electronegativity using odd harmonic dual frequency excitation

The charged particle dynamics in low-pressure oxygen plasmas excited by odd harmonic dual frequency waveforms (low frequency of 13.56 MHz and high frequency of 40.68 MHz) are investigated using a one-dimensional numerical simulation in regimes of both low and high electronegativity. In the low electronegativity regime, the time and space averaged electron and negative ion densities are approxim...

Controlled excitation of ultrasonic transducers

The reproducibility of ultrasonic measurements complicates the interpretation of measurement results. The signal from ultrasonic transducers varies for to several reasons, like manufacturing tolerances in a batch, cable length, amplifier properties etc. A known problem that is caused by this effect is the quantitative interpretation of C-scan images from laminates, particularly the porosity pre...