Providing efficient and clean power is a challenge for devices that range from the micro to macro in scale. Although there has been significant progress in the development of micro-, meso-, and macro-scale power supplies and technologies, realization of many devices is limited by the inability of power supplies to scale with the diminishing sizes of CMOS-based technology. Here, the authors provide an overview of piezoelectric energy harvesting technology along with a discussion of proof of concept devices, relevant governing equations, (...) and figures of merit. They present two case studies: (a) energy capture from the operation of a novel shear and elastic modulus indentation device subjected to applied voltage and (b) energy capture from vibrating commercial bimorph piezoelectric structures mounted on household appliances. Lastly, areas of development needed for realization of commercial energy harvesting devices are suggested. (shrink)

We describe in some detail how to build an infinite computing machine within a continuous Newtonian universe. The relevance of our construction to the Church-Turing thesis and the Platonist-Intuitionist debate about the nature of mathematics is also discussed.

A dialogue between a foreign philosopher and a powerful statesman outline Plato's reflections on the family, the status of women, property rights, and criminal law.

I examine Popper’s claims about Newton’s use of induction in Principia with the actual contents of Principia and draw two conclusions. Firstly, in common with most other philosophers of his generation, it appears that Popper had very little acquaintance with the contents and methodological complexities of Principia beyond what was in the famous General Scholium. Secondly Popper’s ideas about induction were less sophisticated than those of Newton, who recognised that it did not provide logical proofs of the results obtained using (...) it, because of the possibilities of later, contrary evidence. I also trace the historical background to commonplace misconceptions about Newton’s method.Author Keywords: Newton; Popper; Induction; Principia; Kepler’s laws. (shrink)

The ideas and methods of cybernetics are increasingly penetrating the biological and medical sciences, and today we are justified in speaking of a new branch of science: biological and medical cybernetics. This branch already has a number of important and encouraging subfields.

The regular increase in the proportion of resolved feet in the iambic trimeters of Euripides' later plays was first commented upon in 1807 by J. Gottfried Hermann, who therefrom deduced the principle that the date of any play of Euripides could be directly determined from the frequency of its resolutions. This criterion he restated in several of his works in the following years, and when Elmsley objected that it was of uncertain value on account of the small number of plays (...) of certain date by which it might be verified, he replied with a strong defence of his case: he did not, however, develop his principle in detail or give figures in its support. The first scholar to publish the totals of trisyllabic feet in each play was Zirndorfer: relying largely on these, he produced a chronology of Euripides' dramatic composition in several respects superior to any predecessor's. His conclusions were questioned by C. F. W. Müller, who, while accepting Hermann's thesis as being in general correct, doubted its reliability for determining the exact period of a tragedy's composition. Consequently, although he gave the totals of trisyllabic feet en passant, Müller made no attempt to suggest dates. At almost the same time as Müller's treatise appeared, J. Rumpel published an article giving a full and detailed list of references to all trisyllabic feet in Euripides: from this evidence he divided the dramas into four age-groups, but did not go so far as to assign specific dates. (shrink)

We discuss the extent to which the visibility of the heavens was a necessary condition for the development of science, with particular reference to the measurement of time. Our conclusion is that while astronomy had significant importance, the growth of most areas of science was more heavily influenced by the accuracy of scientific instruments, and hence by current technology.

We discuss the philosophical status of the statement that (9n – 1) is divisible by 8 for various sizes of the number n. We argue that even this simple problem reveals deep tensions between truth and verification. Using Gillies's empiricist classification of theories into levels, we propose that statements in arithmetic should be classified into three different levels depending on the sizes of the numbers involved. We conclude by discussing the relationship between the real number system and the physical continuum.