Jean Pierre Hulin Knihy

This work delves into the science of granular media, the most abundant form of solid matter on Earth, consisting of numerous grains that can be consolidated or loose. Unlike traditional classifications of matter, granular materials, akin to a bag of marbles, challenge the standard definitions of solid, liquid, and gas. They serve as a model for various research fields, including engineering, physics, and biology. Pioneering researchers explore the hidden science behind these simple grains, illuminating collective behaviors in disordered environments. The authors begin with the characteristics of individual grains—covering their origins, shapes, and sizes—before examining how they behave when piled or stacked. They discuss the packing fraction, a key factor influencing the properties of granular materials in practical applications. The text also investigates small-scale deformations in disordered grain piles, focusing on friction, and presents theories on different modes of disorder. Concepts such as force chains, arching effects, wet grains, sticky contacts, and inertial effects are thoroughly discussed. By integrating recent numerical simulations with established physics and mechanics principles, this book serves as an accessible introduction to a rapidly evolving field.

The hidden elegance in everyday objects and physical mechanisms, from crumpled paper to sandcastles. Hidden Wonders focuses on the objects that populate our everyday life--crumpled paper, woven fabric, a sand pile--but looks at them with a physicist's eye, revealing a hidden elegance in mundane physical mechanisms. In six chapters--Builders, Creating Shapes, Building with Threads, From Sand to Glass, Matter in Motion, and Fractures--the authors present brief stories, set in locales ranging from the Eiffel Tower to a sandcastle, that illustrate the little wonders hidden in the ordinary. A simple experiment that readers can perform at home concludes each story. More than 200 illustrations bring the stories to life.