vtuking

General Characteristics

General Characteristics

The lion is a well-muscled cat with a long body, large head, and short legs. Size and appearance vary considerably between the sexes. The male’s outstanding characteristic is his mane, which varies between different individuals and populations. It may be entirely lacking; it may fringe the face; or it may be full and shaggy, covering the back of the head, neck, and shoulders and continuing onto the throat and chest to join a fringe along the belly. In some lions the mane and fringe are very dark, almost black, giving the cat a majestic appearance. Manes make males look larger and may serve to intimidate rivals or impress prospective mates. A full-grown male is about 1.8–2.1 metres (6–7 feet) long, excluding the 1-metre tail; he stands about 1.2 metres high at the shoulder and weighs 170–230 kg (370–500 pounds). The female, or lioness, is smaller, with a body length of 1.5 metres, a shoulder height of 0.9–1.1 metres, and a weight of 120–180 kg. The lion’s coat is short and varies in colour from buff yellow, orange-brown, or silvery gray to dark brown, with a tuft on the tail tip that is usually darker than the rest of the coat.

Lions are unique among cats in that they live in a group, or pride. The members of a pride typically spend the day in several scattered groups that may unite to hunt or share a meal. A pride consists of several generations of lionesses, some of which are related, a smaller number of breeding males, and their cubs. The group may consist of as few as 4 or as many as 37 members, but about 15 is the average size. Each pride has a well-defined consisting of a core area that is strictly defended against intruding lions and a fringe area where some overlap is tolerated. Where prey is abundant, a territory area may be as small as 20 square km (8 square miles), but if game is sparse, it may cover up to 400 square km. Some prides have been known to use the same territory for decades, passing the area on between females. Lions proclaim their territory by roaring and by  Their distinctive roar is generally delivered in the evening before a night’s and again before getting up at dawn. Males also proclaim their presence by urinating on bushes, trees, or simply on the ground, leaving a pungent scent behind. and rubbing against bushes leave different scent markings.

As shown in Fig. 13.12, the stress–strain curve for materials that exhibit dynamic recrystallization generally has a broad peak in stress that is different from the monotonic rise to a plateau stress, characteristic of a material that undergoes only dynamic recovery (Fig. 13.1). Under conditions of low Zener–Hollomon parameter, multiple peaks may be exhibited at low strains, as shown in Fig. 13.12.

Figure 13.12. The effect of temperature on the stress–strain curves for 0.68%C steel, deformed in axisymmetric compression, Petkovic et al., 1975 (Petkovic et al., 1975).

A critical (εc) is necessary in order to initiate dynamic recrystallization. This occurs somewhat before the peak (σmax) of the stress-strain curve. For a range of testing conditions, σmax is uniquely related to the Zener–Hollomon parameter.

εc decreases steadily with decreasing stress or Z, although at very low (creep) strain rates the critical strain may increase again (Sellars, 1978).

The size of dynamically recrystallized grains (DR) increases monotonically with decreasing stress. Grain growth does not occur and the grain size remains constant during the deformation.

The flow stress σ and DR are almost independent of the initial grain size D0, although the kinetics of dynamic recrystallization are accelerated in specimens with smaller initial grain sizes.

Dynamic recrystallization is usually initiated at preexisting grain boundaries although for very low strain rates and large initial grain sizes, intravenous granular becomes more important.

vtuking

26 Comments

  1. Reply

    Nice

  2. Reply

    Good

  3. Reply

    Great

  4. Reply

    Good

  5. Reply

    Nice article

  6. Profile photo ofItz Kvng Twitch

    Reply

    Very interesting

  7. Reply

    Very interesting article

  8. Reply

    Okay

  9. Reply

    General

  10. Reply

    Nice

  11. Reply

    nice piece

  12. Reply

    Very interesting you know

  13. Reply

    Very educative write up

  14. Reply

    Good

  15. Reply

    Tnks for this

  16. Reply

    Wonderful

  17. Reply

    Nice

  18. Reply

    nice info thanks for the update

  19. Profile photo ofSommycruz

    Reply

    Good one

  20. Reply

    Good update

  21. Reply

    Good

  22. Reply

    Cool

  23. Reply

    Interesting

  24. Profile photo ofYusuf

    Reply

    Is it so??

  25. Reply

    Nice

  26. Reply

    Really informative……thanks for updating

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these <abbr title="HyperText Markup Language">HTML</abbr> tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>