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Measurement forms an essential part of our view of the world. Our world is measured and calibrated, and we are all subject to the tyranny of these numbers. In this updated and extended edition, Jeffrey Huw Williams outlines the history of measurement; particularly of the International System of units (SI). Since the previous edition, the base units of the SI have been redefined; realizing a 150-year-old dream for a measurement system based on unchanging, fundamental quantities of nature. This change has created a new SI, a Quantum SI, which will significantly change the way we look at nature in a quantitative manner, and greatly facilitate the advance of science. Key Features   Significantly updated and extended new edition The first book to include the new Quantum SI base unit definitions Features wider societal and philosophical implications of a move away from physical standards Outlines the history of the science of measurement, and the origin of the Metric System More than a textbook of metrology, it is also a history of how we have arrived at the Quantum SI

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There are more than 20 million chemicals in the literature, with new materials being synthesized each week. Most of these molecules are stable, and the 3-dimensional arrangement of the atoms in the molecules, in the various solids may be determined by routine x-ray crystallography. When this is done, it is found that this vast range of molecules, with varying sizes and shapes can be accommodated by only a handful of solid structures. This limited number of architectures for the packing of molecules of all shapes and sizes, to maximize attractive intermolecular forces and minimizing repulsive intermolecular forces, allows us to develop simple models of what holds the molecules together in the solid. In this volume we look at the origin of the molecular architecture of crystals; a topic that is becoming increasingly important and is often termed, crystal engineering. Such studies are a means of predicting crystal structures, and of designing crystals with particular properties by manipulating the structure and interaction of large molecules. That is, creating new crystal architectures with desired physical characteristics in which the molecules pack together in particular architectures; a subject of particular interest to the pharmaceutical industry.

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Measurements and experiments are made each and every day, in fields as disparate as particle physics, chemistry, economics and medicine, but have you ever wondered why it is that a particular experiment has been designed to be the way it is. Indeed, how do you design an experiment to measure something whose value is unknown, and what should your considerations be on deciding whether an experiment has yielded the sought after, or indeed any useful result? These are old questions, and they are the reason behind this volume. We will explore the origins of the methods of data analysis that are today routinely applied to all measurements, but which were unknown before the mid-19th Century. Anyone who is interested in the relationship between the precision and accuracy of measurements will find this volume useful. Whether you are a physicist, a chemist, a social scientist, or a student studying one of these subjects, you will discover that the basis of measurement is the struggle to identify the needle of useful data hidden in the haystack of obscuring background noise.

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The present theme concerns the forces of nature, and what investigations of these forces can tell us about the world we see about us. The story of these forces is long and complex, and contains many episodes that are not atypical of the bulk of scientific research, which could have achieved greater acclaim 'if only…'. The intention of this book is to introduce ideas of how the visible world, and those parts of it that we cannot observe, either because they are too small or too large for our scale of perception, can be understood by consideration of only a few fundamental forces. The subject in these pages will be the authority of the commonly termed, laws of physics, which arise from the forces of nature, and the corresponding constants of nature (for example, the speed of light, c, the charge of the electron, e, or the mass of the electron, me).

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