critical pressure gradient
111Manhattan Project — This article is about the atomic bomb project. For other uses, see Manhattan Project (disambiguation). Manhattan District The Manhattan Project created the first nuclear bombs. The Trinity test …
112Refractive index — Refraction of light at the interface between two media. In optics the refractive index or index of refraction of a substance or medium is a measure of the speed of light in that medium. It is expressed as a ratio of the speed of light in vacuum… …
113building construction — Techniques and industry involved in the assembly and erection of structures. Early humans built primarily for shelter, using simple methods. Building materials came from the land, and fabrication was dictated by the limits of the materials and… …
114roads and highways — ▪ transportation Introduction traveled way on which people, animals, or wheeled vehicles move. In modern usage the term road describes a rural, lesser traveled way, while the word street denotes an urban roadway. Highway refers to a major… …
115Glossary of rail terminology — Rail transport Operations Track Maintenance High speed Gauge Stations …
116Lightning — This article is about the atmospheric electrical phenomenon. For other uses, see Lightning (disambiguation). See also: Lightning strike Lightning striking Atlanta, United States Lightning is an atmospheric electrostatic discharge (spar …
117nature, philosophy of — Introduction the discipline that investigates substantive issues regarding the actual features of nature as a reality. The discussion here is divided into two parts: the philosophy of physics and the philosophy of biology. In this… …
118Membrane potential — Differences in concentration of ions on opposite sides of a cellular membrane lead to a voltage called the membrane potential. Many ions have a concentration gradient across the membrane, including potassium (K+), which is at a high inside and a… …
119River — For other uses, see River (disambiguation). The Tigris River near Hasankeyf, in southeastern Turkey …
120Microbial enhanced oil recovery — (MEOR) is a biological based technology consisting in manipulating function or structure, or both, of microbial environments existing in oil reservoirs. The ultimate aim of MEOR is to improve the recovery of oil entrapped in porous media while… …
