In a recent paper by Lyon et al. (Flow through Collapsible Tubes at Low Reynolds Numbers. Circ Res 47: 68-73, 1980), the authors contend that waterfall models adequately predict flow through a Starling resistor only for Reynolds numbers <1. Their basic conclusion was that caution should be used when applying waterfall models to the mammalian circulatory system since Reynolds numbers are usually...

Catastrophic outburst floods carved amphitheater-headed canyons on Earth and Mars, and the steep headwalls of these canyons suggest that some formed by upstream headwall propagation through waterfall erosion processes. Because topography evolves in concert with water flow during canyon erosion, we suggest that bedrock canyon morphology preserves hydraulic information about canyon-forming floods...

Headwater accident is a natural phenomenon that occurs in every flow channel, resulting in tremendous incidents that involve vulnerable lives and destruction of its surroundings. This study focuses on simulation of potential headwater accidents at Lata Kinjang waterfall (Perak, Malaysia) with the aim of understanding the behavior of headwater accidents from the hydraulic aspect. By deploying th...

Software quality is one of our most important software concerns. Agile methods may produce software faster but we also need to know how they meet our quality requirements. In this paper we compare the waterfall model with agile processes to show how agile methods achieve software quality. We also show how agile methods attain quality under time pressure and in an unstable requirements environme...

Computer R apid change in information technology brings with it a frequent need to undo the effects of previous culture change efforts. This process, while often challenging and frustrating, offers numerous rewards for success. Organizations can change from slow, reactive, adversarial, separated software and systems engineering processes to unified, concurrent processes. These processes better ...

Software development life cycle or SDLC for short is a methodology for designing, building, and maintaining information and industrial systems. So far, there exist many SDLC models, one of which is the Waterfall model which comprises five phases to be completed sequentially in order to develop a software solution. However, SDLC of software systems has always encountered problems and limitations...

THE SOFTWARE DEVELOPMENT LIFE CYCLE (SDLC) MODEL IS A FUNDAMENTAL AND IMPORTANT CONCEPT IN THE HELD OF SOFTWARE ENGINEERING. AUTOMATION OF THE SOFTWARE PROCESS USING C A S E TECHNOLOGY IS BASED ON THE SOFTWARE DEVELOPMENT UFE CYCLE CONCEPT. THOUGH C A S E TECHNOLOGY IS A MATURE SOFTWARE TECHNOLOGY, THERE IS LTTTLE CHANGE IN THE LIFE CYCLE MODELS USED BY C A S E SINCE THE 'WATERFALL* MODEL WAS I...

, where E(x=La) is the erosion rate at the upstream end of the flow acceleration zone above a waterfall, Fr is the Froude number at this setting, and n ranges between 0.5–1.7. This amplification expression suggests that erosion at the lip could be as much as 2–5 times higher relative to erosion at a normal setting with identical hydraulic geometry. Utilizing this erosion amplification expressio...