" In fact, current QCD lattice models seem to suggest a significantly lower mass of these quarks from that of this table. The fermions can be arranged in three generations, the first one consisting of the electron, the up and down quarks, and the electron neutrino . All ordinary matter is made from first generation particles; the higher generation particles decay quickly into the first generation ones and can only be generated for a short time in high-energy experiments. The reason for arranging them in generations is that the four fermions in each generation behave almost exactly like their counterparts in the other generations; the only difference is in their masses. For example, the electron and the muon both have half-integer spin and unit electric charge, but the muon is about 200 times more massive. The electron and the electron-neutrino, and their counterparts in the other generations, are called "leptons", "weakly interacting particles". Unlike the quarks, they do not possess a quality called "color", and their interactions are only weak and electromagnetic, and fall off with distance. Ship Model World War 2 On the other hand, the strong or "color" force between quarks gets stronger with distance, so that quarks are always found in colorless combinations called hadrons, a phenomenon known as quark confinement. These are either fermionic baryons composed of three quarks (the proton and neutron being the most familiar example) or bosonic mesons composed of a quark-antiquark pair (such as pions). "

" To speed assembly, between 1915 and 1925 it was only available in one color, black. Black paint was also cheaper and more durable. Henry Ford is reputed to have made the statement "Any customer can have a car painted any color that he wants so long as it is black. " Model Ts in different colors were produced from 1908 to 1914, and then again from 1926 to 1927. By 1914, the assembly process for the Model T had been so streamlined it took only 93 minutes to assemble a car. That year Ford produced more cars than all other automakers combined. The Model T was a great commercial success, and for years in the late 1910s and early 1920s it was estimated that more than half of all motorcars in existence in the world were Model T Fords. Model Cargo Ship In fact, it was so successful that Ford did not purchase any advertising between 1917 and 1923; in total, more than 15 million Model Ts were manufactured, more than any other model of automobile for almost a century. This record has now been surpassed by the Volkswagen Beetle, and the Toyota Corolla and Ford F-Series nameplates have both sold more. "