Plates of 3–5 mm in thickness were extracted from an AZ91D ingot and then butt joints of the plates were produced using tungsten inert gas (TIG) welding method. The TIG arc was also used to deposit welding beads on some of the thin plates. No cracking was found in the butt joints. However, hot cracking was always observed to propagate from the heat affected zone (HAZ) under the welding bead int...

This study investigated the effect of oxygen and micro-cracking on the flotation of low grade nickel sulphide ore. The ore treated contained serpentine minerals which have a history of being difficult to process efficiently. The use of oxygen as a bubbling gas has been noted to be effective because it increases the pulp potential. The desired effect of micro cracking the ore is that the nickel ...

Petroleum refineries utilize thermal cracking, catalytic cracking and hydrogenation processes to produce high quality oil products. Hydrodesulfurization is one of the most important methods to remove sulfur from petroleum fractions. Heavy oil contains various types of sulfur compound. The structure of the sulfur compounds affects the ease of sulfur removal1). Acyclic sulfur compounds including ...

To reveal the breakdown mechanism of dry hot rock (HDR) induced by liquid nitrogen (LN) fracturing, laboratory tests were performed on high temperature granite using specialized apparatus. The pressure and fracture morphology granites subjected to different heating temperatures thermal treatments analyzed. results showed that decreased with increasing. As increased from 25 °C 300 °C, 40.63%. In...

(This is part 2, continued from “Use of harsh Wafer Probing to Evaluate Traditional Bond Pad Structures”). Goals for circuit under pad (CUP) in aluminum – silicon dioxide (Al – SiO2) based IC pad structures include the design of metal interconnects in all layers beneath the pad Al, and the ability to withstand harsh probing and wirebonding stress without SiO2 cracking, without deforming or bend...

Brittle materials propagate opening cracks under tension. When stress increases beyond a critical magnitude, then quasistatic crack propagation becomes unstable. In the presence of several precracks, a brittle material always propagates only the weakest crack, leading to catastrophic failure. Here, we show that all these features of brittle fracture are fundamentally modified when the material ...

Password policies alone do not stand a chance of securing computer systems which rely on the use of secretbased, password authentication methods. The enforcement of “strong” passwords via pro-active password strengthening utilities and password cracking tools should be employed by system administrators to reduce the number of “weak” passwords in a computer system. With the availability of low-c...

In this letter, the quantity effect of radial cracks on the cracking propagation behavior as well as the circular crack generation on the impacted glass plate within the sandwiched glass sheets are experimentally investigated via high-speed photography system. Results show that the radial crack velocity on the backing glass layer decreases with the crack number under the same impact conditions ...

Effect of solid solution treatment (T4) on stress corrosion cracking (SCC) behavior of an as-forged Mg-6.7%Zn-1.3%Y-0.6%Zr (in wt.%) alloy has been investigated using slow strain rate tensile (SSRT) testing in 3.5 wt.% NaCl solution. The results demonstrated that the SCC susceptibility index (ISCC) of as-forged samples was 0.95 and its elongation-to-failure (εf) was only 1.1%. After T4 treatmen...

The three major distress conditions affecting the performance of asphalt pavements are permanent deformation or rutting, fatigue or load associated cracking, and low temperature or thermal cracking. In an earlier technical topics article (Fall, 1998), we examined the causes of fatigue cracking and the importance of good compaction during construction to help minimize this type of distress. In t...