Abstract:This paper addresses the short-term scheduling problem for the ethylene cracking process with feedstocks and energy constraints. The cracking production of ethylene is a process with units that have decaying performance, requiring periodic cleanup to restore their performance. Under the condition of limited feedstocks, the production operating mode of the cracking furnaces is to keep y...

At the age of 3.5 years, wild chimpanzees at Bossou, Guinea, begin to use hammer and anvil stones to crack oil-palm nuts to get the kernels. To clarify the developmental processes, the authors did a field experiment in which stones and oil-palm nuts were provided. Infant chimpanzees' stone-nut manipulation was observed and video recorded. Data were collected from 3 infants younger than 4 years ...

Two problems of technological importance for microelectromechanical systems ~MEMS! and microelectronics industry are addressed: fatigue of thin films and nanoscale film cracking. A device is described that can ~1! conduct biaxial fatigue tests on thin films and ~2! be utilized to study fracture patterns in nanoscale coatings under biaxial stress state. Thin-film specimens, in the form of circul...

Article history: Received: 11.03.2013. Received in revised form: 02.04.2013. Accepted: 02.04.2013. This paper puts forward an innovative criterion in the cellar automata (CA) technique for both matching zone similarity and mapping failure pattern of masonry wall panel. The criterion proposed in this paper is a two-step matching method. Firstly, calculate the state values of the cells in the bas...

Existing design guidelines for concrete hinges consider bending-induced tensile cracking, but the structural behavior is oversimplified to be time-independent. This is the motivation to study creep and bending-induced tensile cracking of initially monolithic concrete hinges systematically. Material tests on plain concrete specimens and structural tests on marginally reinforced concrete hinges a...

Cross-linked protein crystals (CLPCs) are very useful materials in applications such as biosensors, catalysis, and X-ray crystallography. Hence, preparation of CLPCs is an important research direction. During the preparation of CLPCs, an often encountered problem is that cracks may appear in the crystals, which may finally lead to shattering of the crystals into small pieces and cause problem i...

Researchers are currently developing new value-added uses for almond shells, an abundant agricultural by-product. Almond varieties are distinguished by processors as being either hard or soft shelled, but these two broad classes of almond also exhibit varietal diversity in shell morphology and physical characters. By defining more precisely the physical and chemical characteristics of almond sh...

Solutions are presented for the elastic plane-strain problem of a crack in a coating on a compliant substrate of finite thickness. Analysis of the problem shows that substrate thickness has a significant effect on the steady-state energy release rate for channel cracks. This is so over a wide range of elastic mismatch between film and substrate, but is especially important if the substrate is m...

Corrosion-fatigue, a cracking mechanism in fossil-fueled generating plants, predominately occurs in the water walls and economizers of sub-critical plants. Cracking attributed to corrosion-fatigue has occurred in water wall tubing of both membrane and tangential designs. The occurrence (particularly in membrane water wall tubing) presents a challenge for nondestructive evaluation (NDE) because ...

The cracking resistance of Alloy 600, Alloy 690 and their welds, EN82H and EN52, was characterized by conducting JICtests in air and hydrogenated water. All test materials displayed excellent toughness in air and high temperature water, but Alloy 690 and the two welds were severeiy embrittled in low temperature water. In 54°C water with 150 cc Hz/kg H20, JICvalues were typically 70~o to !35Y0 ]...