Month: July 2014

When selecting optics for cameras Canon eos 500D is necessary to take into account crop factor – in other words, to determine the real value of the zoom range lens, the focal lengths must be multiplied by 1.6. Model is compatible with all lenses Canon ef, but it is more preferable to use optical series EF-S, the focal lengths of which are shifted to wide-area, and design allows for smaller size and regular structure of light detectors. Moreover, with similar optical characteristics, EF-S lenses easier and cheaper counterparts, fired from the expectation of full kadr. Despite their belonging to the amateur class, Canon eos 500D has an excellent feature that, coupled with excellent features, it allows you to use this camera for professional photography. On the other hand, ease of management and intelligent automation makes the model an excellent choice for beginners who buy a camera "for growth".

Focusing System Canon eos 500D provides nine located in the diamond-shaped points Focus, which covers a large part of the frame. Traditionally for the eos af system is available in one of three modes: single-frame, witness, or intellectually. The model is able to maintain autofocus in face priority mode, as well as the model 450D, is able to operate in direct sight picture through the monitor (Live View). Measuring the exposure occurs on 35-zonnomu spc. In the evaluative metering by conjugation zone metering with the focus point, which increases measurement accuracy. It is also possible to select center-weighted and partial (4% or 9% of frame) measurement methods.

Exposure can occur in one of the scene modes (Auto, Portrait, Landscape, Close-up, Sports, Night Portrait, No Flash, video), or in creative zone modes (Program ae, Shutter Shutter-priority, Shutter-priority ae, manual mode, auto exposure control depth of field). If necessary, the photographer can use the correction and exposure bracketing. White balance can installed either automatically or manually: Preset or through customization. Ability to set color temperature values directly in degrees Kelvin is missing, but it partially offset by the presence of the model features a color shift in the areas from blue to amber and from crimson to green. It is also possible White Balance Bracketing. The model is equipped with built-in flash and has the possibility of joining the outside. You can sync at 1 / 200 sec., Wireless control group of flashes, and second curtain sync. It is also possible correction and bracketing power impulsa. can be recorded in raw or jpeg. If desired, images can be "set" styles, which accentuate the character of the image (portrait, landscape, etc.). Greatly simplify the work of the photographer user settings (up to 39 settings of 13 functions). Despite the large matrix resolution, the camera has a high rate – 3.4 frames / sec. with a maximum length series of 170 shots (JPEG). Video recording is carried out in the H.264 format with a maximum 1920×1080 resolution at a frequency of 20 frames / sec. or a lower resolution at 30 frames / sec. Record in the H.264 format provides a minimum file size while preserving superior image quality.

Matter, space, time and movement is not divisible ad infinitum, and have limits of divisibility. And it is these, rather than the opposite properties can be programmed into the computer. And what about the speed of movement? Until the middle of the xix century. in physics took place disputes between supporters of the so-called 'long range' and 'short range'. Long-range interaction is instantaneous (without intermediaries, through a vacuum) the transfer of administration (eg, gravitational or electric) of one body on another, no matter how far these bodies may be located from each other, that is the principle of long-range acknowledges the existence of an infinitely high speed. Supporters of 'short range' believed that the body interact only with finite rates, and by direct contact or through the physical fields (gravitational, electromagnetic, etc.) – through intermediaries, which ultimately also interact directly with the body, their Radiant and with the body absorbing them.

Supporters of long-range were eminent scientists, in particular, Ampere and pendant. Only Faraday firmly on the position of the short-range, and finally secured a position Maxwell, creating a middle of the xix century, a mathematically perfect electromagnetic field theory, which proved the finiteness of the rate of interaction. Infinity – including infinite speed – program in your computer impossible, because the victory of supporters of the 'short range' means an addition of one more weights on the scales in favor of an artificial origin of our universe. But there are even more stringent conditions to the Universe can be programmed in the computer.

The engineering significance of creep Creep strains in its simplest form is the progressive accumulation of plastic strain in a specimen or machine part under stress at elevated temperature over a period of time. Creep failure occurs when the accumulated creep strain results in a deformation of the machine part that exceeds the design limits. Creep rupture is an extension of the creep process to the limiting condition where the stressed member actually separates into two parts. Stress is a term used interchangeably by many with creep rupture rupture; However, others reserve the term stress rupture for the rupture termination of creep process in which steady-state creep is never reached and use the term creep rupture for the rupture termination of a creep process in which a period of steady-state creep has persisted. Figure 26 illustrates these differences. The interaction of creep and stress rupture with cyclic stressing and the fatigue process has not yet been clearly understood but is of great importance in many modern high-performance engineering systems. Creep strains of engineering significance are not usually encountered until the operating temperatures reach an absolute temperature. Not only is excessive deformation due to creep an important consideration, but other consequences of the creep process may also be important.

These might include creep rupture, thermal relaxation, dynamic creep under cyclic loads or cyclic temperatures, creep and rupture under mulfaxial states of stress, cumulative effects, and effects creep of combined creep and fatigue. Creep deformation and rupture are initiated in the grain boundaries and proceed by sliding and separation. Thus, creep rupture failures are intercrystalline, in contrast, for example, to the transcrystalline failure exhibited by room temperature surface fatigue failures. Although creep is a plastic flow phenomenon, the intercrystalline failure path gives a rupture surface that has the appearance of brittle fracture. Creep rapture typically occurs without necking and without warning. Current state-of-the-art knowledge does not permit a reliable prediction of creep or stress rupture properties on a theoretical basis. Furthermore, there seems to be little or no correlation between the creep properties of a material and its room temperature mechanical properties.

Therefore, test data and empirical methods of extending these data are relied on heavily for prediction of creep behavior under anticipated service conditions. Metallurgical stability under long – time exposure to elevated temperatures is mandatory for good creep-resistant alloys. Prolonged time at elevated temperatures acts as a tempering process, and any improvement in properties originally gained by quenching may be lost. Resistance to oxidation and other corrosive media are also usually important attributes for a good creep-resistant alloy. Larger grain size may also be advantageous since this reduces the length of grain boundary, where much of the creep process resides. We provide Professional technology, excellent product quality and intimate after-sales service when you purchase Rotary dryer, raymond mill, from our company.As a professional mining machinery exporter, we will win your trust with our delivery speed, Enterprises Credit and product quality.