Before the spread of the Internet, everyone dealt with letters and stamps. One of the pastimes of that time was to separate the stamp from the envelope and keep it. I also had a stamp album when I was a teenager. Therefore, it is not strange that when I started my career as a welding engineer, I looked for the connection between postage stamps and welding.
The file below is the result of that effort.
PS: Unfortunately, I have not written down the references that I used.
خواندن بعدی
اگر به موسیقی ایرانی علاقه دارید شاید دوست داشته باشید بدانید که قدیمیترین تصنیف کدام است. شعر قدیمیترین تصنیف ایرانی …
In below tables the elements are arranged by atomic number with the year of discovery and the discoverer. The discovery of an element made the discoverer well known and also gave credit to his/her country. Source: Encyclopedia of the Elements, …
