الهام طهرانی

This research is a laboratory study to improve the geotechnical properties of sandy soils. Concrete waste with a grain size of 1.2 to 1 inch was used for this purpose. The effect of using concrete waste at 0, 10, 20 and 30 weight percent on dry sandy soil in two loose and dense states was investigated. Based on the results of the direct cutting test, the addition of concrete waste has increased the shear strength and the internal friction angle of the soil; The loose samples made with ٪30 of concrete waste had the greatest effect, so adding ٪30 of concrete waste to loose sand increased the internal friction angle of the soil by ٪32 and the shear strength by ٪42 Similarly, adding ٪10 of concrete waste to dense sand increased the internal angle of friction of the soil by ٪4 and the shear strength by ٪6.

One of the books in the field of astronomy and mathematics written in the 11th AH/17th AD century, during the Safavid era, is Tohfˉa Abbasiyya by Mirza Qazi b. Kashifuddin Mohammad Yazdi Ardakani. This book is still in manuscript form, and no research has been done about it. The purpose of this research is to introduce the manuscripts and study the book's scientific position in astronomy and the history of astronomy in the Safavid era.

Research Method /Approach: 

The research method is descriptive-analytics that gathers the manuscripts of Tohfˉa Abbasiyya book by referring to the libraries and lists written in the field of manuscripts and studies the content, and compares the copies.

Qazi Yazdi wrote the book Tohfˉa Abbasiyya in the introduction of an instrument, Maqalid al-Samawat va al-‘Arz (The reins of the heavens and the earth), which he made instead of Zaat al-Sha‘baatin (With two branches). The results revealed that there are five manuscripts of the book in Iran's libraries, which are very similar and almost complete, and only some pages of the Parliament copy are missing. All copies have nineteen illustrations that were precisely drawn with ruler, compass and geometrical tools; especially the Astan Quds Razavi library copy which has illustrated the astronomical positions with different colors. At least two copies were scripted in the author's era, although the scriber is unknown. In three chapters of the book Tohfˉa Abbasiyya, Qazi, while criticizing the Zaat al-Sha‘baatin system, which has been in use since the time of Ptolemy, has expressed the advantages of the Maqalid al-Samawat system. Then he presents and criticizes the ideas of great astronomers and mathematicians from Greece and the Islamic period to his own time, relying on their books.
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