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  2. Rotamer - Wikipedia

    en.wikipedia.org/wiki/Rotamer

    The textbook explanation for the existence of the energy maximum for an eclipsed conformation in ethane is steric hindrance, but, with a C-C bond length of 154 pm and a Van der Waals radius for hydrogen of 120 pm, the hydrogen atoms in ethane are never in each other's way. The question of whether steric hindrance is responsible for the eclipsed ...

  3. File:Ethane conformations and relative energies.svg - Wikipedia

    en.wikipedia.org/wiki/File:Ethane_conformations...

    B is highest & A lowest in energy. A is thus the most stable conformation. Valleys are local energy minima. A can thus be classified as a rotamer (a class of conformers). Peaks are not rotamers, & are caused by repulsive forces of the hydrogens. Source for conformation names & rotamer classification:

  4. Soil formation - Wikipedia

    en.wikipedia.org/wiki/Soil_formation

    Soil formation, also known as pedogenesis, is the process of soil genesis as regulated by the effects of place, environment, and history. Biogeochemical processes act to both create and destroy order ( anisotropy ) within soils.

  5. Soil mechanics - Wikipedia

    en.wikipedia.org/wiki/Soil_mechanics

    Different criteria can be used to define the "shear strength" and the "yield point" for a soil element from a stress–strain curve. One may define the peak shear strength as the peak of a stress–strain curve, or the shear strength at critical state as the value after large strains when the shear resistance levels off.

  6. Rotamers - Wikipedia

    en.wikipedia.org/wiki/Syn_conformation

    The textbook explanation for the existence of the energy maximum for an eclipsed conformation in ethane is steric hindrance, but, with a C-C bond length of 154 pm and a Van der Waals radius for hydrogen of 120 pm, the hydrogen atoms in ethane are never in each other's way. The question of whether steric hindrance is responsible for the eclipsed ...

  7. Physical properties of soil - Wikipedia

    en.wikipedia.org/wiki/Physical_properties_of_soil

    Soil texture is determined by the relative proportion of the three kinds of soil mineral particles, called soil separates: sand, silt, and clay. At the next larger scale, soil structures called peds or more commonly soil aggregates are created from the soil separates when iron oxides , carbonates , clay, silica and humus , coat particles and ...

  8. Soil organic matter - Wikipedia

    en.wikipedia.org/wiki/Soil_organic_matter

    The dry matter consists mainly of carbon, oxygen, and hydrogen. Although these three elements make up about 92% of the dry weight of the organic matter in the soil, other elements present are essential for the nutrition of plants, including nitrogen, phosphorus, potassium, sulfur, calcium, magnesium, and many micronutrients. [1]

  9. Soil - Wikipedia

    en.wikipedia.org/wiki/Soil

    However, humus in its most stable forms may persist over centuries if not millennia. [175] Charcoal is a source of highly stable humus, called black carbon, [176] which had been used traditionally to improve the fertility of nutrient-poor tropical soils.