A Technical Study Evaluating the Three Major Brands of Spark Plugs

In this research study the researcher will prove which spark plugs will perform the best in all operating conditions. These conditions are structural strength, anti-fouling characteristics, carbon tracking resistance, extended operational performance, high temperatures, high pressures, high voltage, seal ability, combustion performance, and the ability to resist detonation and pre-ignition

Engineering needs environmental and global thinkers: a contextual analysis of student learning preferences

The need for engineering graduates who are environmentally and globally aware is now a recognised priority in professional practice. This paper presents an analysis of learning preferences of entry level students in a course which builds an early awareness of global environmental practice. The course on Engineering and the Environment started in 1991 as part of the undergraduate Environmental Engineering program at RMIT University. Subsequently the course was extended to Geological and then to Civil Engineering programs. The curriculum has paralleled the development of environmental practice in the professions of engineering and mining and provides a fundamental environmental context for students' subsequent learning in their programs and on-going professional practice. Curriculum development and some specific learning activities are briefly outlined. A challenge has been how to engage a diverse and increasingly large cohort of almost several hundred students in "non traditional" engineering lectures. A detailed analysis of student responses to a set of multiple choice exam questions has been conducted to test the hypothesis that various factors such as student choice of program may influence receptivity to different modes of learning and curriculum content. The study shows no significant difference between the various groups in regards to preference for evaluative type environmental learning, versus more traditional factual based engineering learning

On the security of a new image encryption scheme based on chaotic map lattices

This paper reports a detailed cryptanalysis of a recently proposed encryption scheme based on the logistic map. Some problems are emphasized concerning the key space definition and the implementation of the cryptosystem using floating-point operations. It is also shown how it is possible to reduce considerably the key space through a ciphertext-only attack. Moreover, a timing attack allows the estimation of part of the key due to the existent relationship between this part of the key and the encryption/decryption time. As a result, the main features of the cryptosystem do not satisfy the demands of secure communications. Some hints are offered to improve the cryptosystem under study according to those requirements.Comment: 8 pages, 8 Figure

Metachronal waves in the flagellar beating of Volvox and their hydrodynamic origin.

Groups of eukaryotic cilia and flagella are capable of coordinating their beating over large scales, routinely exhibiting collective dynamics in the form of metachronal waves. The origin of this behavior--possibly influenced by both mechanical interactions and direct biological regulation--is poorly understood, in large part due to a lack of quantitative experimental studies. Here we characterize in detail flagellar coordination on the surface of the multicellular alga Volvox carteri, an emerging model organism for flagellar dynamics. Our studies reveal for the first time that the average metachronal coordination observed is punctuated by periodic phase defects during which synchrony is partial and limited to specific groups of cells. A minimal model of hydrodynamically coupled oscillators can reproduce semi-quantitatively the characteristics of the average metachronal dynamics, and the emergence of defects. We systematically study the model's behaviour by assessing the effect of changing intrinsic rotor characteristics, including oscillator stiffness and the nature of their internal driving force, as well as their geometric properties and spatial arrangement. Our results suggest that metachronal coordination follows from deformations in the oscillators' limit cycles induced by hydrodynamic stresses, and that defects result from sufficiently steep local biases in the oscillators' intrinsic frequencies. Additionally, we find that random variations in the intrinsic rotor frequencies increase the robustness of the average properties of the emergent metachronal waves.This work was supported in part by the EPSRC (M.P.), ERC Advanced Investigator grant 247333 and a Senior Investigator Award from the Wellcome Trust.This is the final version. It was first published by Royal Society Publishing at http://rsif.royalsocietypublishing.org/content/12/108/20141358

Long-range interactions, wobbles, and phase defects in chains of model cilia

Eukaryotic cilia and flagella are chemo-mechanical oscillators capable of generating long-range coordinated motions known as metachronal waves. Pair synchronization is a fundamental requirement for these collective dynamics, but it is generally not sufficient for collective phase-locking, chiefly due to the effect of long-range interactions. Here we explore experimentally and numerically a minimal model for a ciliated surface: hydrodynamically coupled oscillators rotating above a no-slip plane. Increasing their distance from the wall profoundly affects the global dynamics, due to variations in hydrodynamic interaction range. The array undergoes a transition from a traveling wave to either a steady chevron pattern or one punctuated by periodic phase defects. Within the transition between these regimes the system displays behavior reminiscent of chimera states.Human Frontier Science Program; Wellcome Trust; EU ERC CoG Hydrosyn