In 11 cemeteries of Cundinamarca and Meta (Colombia) departments we found 203 nests of stingless bees pertaining to 15 species.The majority of the found nests (61%) belong to genus Nannotrigona Cokerell, 1922.Nannotrigona mellaria was the specie with the M Hoodies greater nests number and higher population; Trigona (Tetragonisca) angustula was foun
Filling mining is a main technology of mining coal resources under buildings, and it has a good effect on preventing ground subsidence.Taking Wangtaipu coal mine of the Shanxi Jincheng Anthracite Coal Mining Group as Tinting the engineering background, in order to solve the problem of traditional closed brick wall at the end of working face, which
High-voltage transmission lines are the main facilities for power transmission, and they are mainly composed of aluminum conductor steel-reinforced (ACSR).Over long-term outdoor use, overhead transmission lines will encounter lightning strikes, chemical pollutant corrosion, deicing, wind vibration, and other external forces.This often results in a
Manufacturers face challenges when dealing with abrasives that lose roundness, wear excessively, and suffer from pitting of the surface of the grinding wheel that needs rectification using dressing techniques.Nanostructured abrasive grits manufactured by hybrid fusion processes and by sintering/extrusion/printing processes are found to reduce pitti