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This standard defines property classes, the metric equivalent of a screw grade, that are almost identical to those defined by ISO 898-1, [2] except for the addition of the 8.8.3 and 10.9.3 classes. These two additional standards are fasteners that have the same mechanical properties as their base property class (i.e. 8.8 and 10.9), but are made ...
The oldest known mathematics textbook is the Rhind papyrus, dated from c. 1650 BCE in Egypt. [184] Due to a scarcity of books, mathematical teachings in ancient India were communicated using memorized oral tradition since the Vedic period (c. 1500 – c. 500 BCE). [185]
As a result, the 2010 exam session introduced the grade A*—which serves to distinguish between the better candidates. [9] Prior to the 2017 reforms, the A* grade in maths was awarded to candidates who achieve an A (480/600) in their overall A Level, as well as achieving a combined score of 180/200 in modules Core 3 and Core 4.
Using isobutane, gasoline-grade "blendstocks" are generated with high branching for good combustion characteristics. Typical products created with isobutane are 2,4-dimethylpentane and especially 2,2,4-trimethylpentane. [7] Typical acid-catalyzed route to 2,4-dimethylpentane.
Probability density function (pdf) or probability density: function whose value at any given sample (or point) in the sample space (the set of possible values taken by the random variable) can be interpreted as providing a relative likelihood that the value of the random variable would equal that sample.
The first light bulbs ever lit by electricity generated by nuclear power at EBR-1 at Argonne National Laboratory-West, December 20, 1951. [7]The process of nuclear fission was discovered in 1938 after over four decades of work on the science of radioactivity and the elaboration of new nuclear physics that described the components of atoms.
Ethiopia, [c] officially the Federal Democratic Republic of Ethiopia, is a landlocked country located in the Horn of Africa region of East Africa.It shares borders with Eritrea to the north, Djibouti to the northeast, Somalia to the east, Kenya to the south, South Sudan to the west, and Sudan to the northwest.
Radiation exposure such as ultraviolet radiation and radioactive material is a risk factor for cancer. [72] [73] [74] Many non-melanoma skin cancers are due to ultraviolet radiation, mostly from sunlight. [73] Sources of ionizing radiation include medical imaging and radon gas. [73] Ionizing radiation is not a particularly strong mutagen. [75]