[Solved] Strikes or lockouts that have an adverse effect on the national interest may be declared national emergency disputes. Sediment: Particles of organic or inorganic matter that accumulate in a solid layer on the bottom of a body of water or other liquid due to the process of sedimentation. Naked Eye: Relating to the ability to see or observe an object or event unaided by any optical instruments, such as telescopes or microscopes. Sandstone: A sedimentary rock consisting of sand-sized mineral particles or rock fragments compacted and cemented together. Natural Cements: Substances that occur in nature, which can act to bind materials together through a chemical or physical process.