中期プレイストセンのアチェーレ族のような石工学 ボーゼ盆地,中国南
1Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Box 643, Beijing 100044, China.
まとめ
東アジアで最も古い大型切削工具 (LCT) は,80万3000年前のもので,南中国で発見された. これらのアチェーレアのような石器は,この地域の初期の技術的進歩を示しています.
科学分野:
- 考古学考古学とは
- 旧石器時代の研究
- 東アジア史前史 (東アジア史前史)
背景:
- プレイストセンの半ばの東アジアにおける初期の人間の存在と技術的な能力は,完全に理解されていません.
- 以前の研究は,後期に焦点を当てており,この地域の最も初期の洗練された石器工業に関する知識のギャップを残しています.
関連する概念動画
Quarrying of Stone
Quarrying is the process of extracting stone from a quarry, where specialized techniques are employed to remove large blocks of stone safely and efficiently. This process can involve controlled explosions or more precision-oriented methods such as cutting and drilling.
One common method involves using a diamond belt saw to cut large blocks from the quarry face. These blocks can be about 50 feet long and 12 feet high. After the initial vertical cut, drilling is performed at the base of the block.
One common method involves using a diamond belt saw to cut large blocks from the quarry face. These blocks can be about 50 feet long and 12 feet high. After the initial vertical cut, drilling is performed at the base of the block.
Stone Masonry
Stone masonry is a construction technique that uses individual stones to build structures and can be categorized into two main types: rubble and ashlar. Rubble masonry uses uneven, naturally shaped stones such as river rocks or fragments from quarries. This method often requires the mason to select and possibly shape each stone to fit the designated space, ensuring a proper build, even with irregular stone sizes and shapes. Ashlar masonry, on the other hand, employs uniformly cut stones that...
Placing Concrete
The concrete is placed as close as possible to its final position to avoid segregation. The placed concrete is then fully compacted to expel the entrapped air, and the next layer of concrete is laid while the underlying layer is still in the plastic state. The rate at which concrete is placed and compacted is kept equal.
While placing concrete, care is taken to ensure that the concrete is laid in uniform layers, and hand shoveling and moving concrete using poker vibrators is avoided. Also,...
While placing concrete, care is taken to ensure that the concrete is laid in uniform layers, and hand shoveling and moving concrete using poker vibrators is avoided. Also,...
Preplaced Aggregate Concrete
Preplaced aggregate concrete is ideal for construction environments that are not easily accessible. The process begins by properly wetting the gap-graded coarse aggregates to remove the dirt, then placing it in the form and compacting it. Voids are filled with a mortar mix pumped under pressure through slotted pipes. This mortar typically consists of Portland cement, pozzolan, fine aggregates, water, and a fluidizing aid. The pozzolan helps reduce bleeding and segregation while improving the...
Design Example: Managing Concrete Workability
This example deals with managing the workability of concrete for a raft foundation project under hot weather conditions. Workability is crucial for ensuring the concrete is easy to place, compact, and finish. In this scenario, a slump test — a common method to measure the workability of fresh concrete — initially indicated low workability. This was attributed to the rapid water loss from the concrete mix, exacerbated by the high temperatures causing the course aggregates to heat up.
To address...
To address...
Design Example: Maintaining Level of an Embankment
Constructing a roadway embankment over uneven terrain requires precise leveling to ensure stability and proper drainage. Surveyors use a leveling instrument and staff to calculate ground elevations and determine the required fill material at each point along the embankment alignment.The process begins by positioning a leveling instrument near a benchmark with a known elevation. A backsight reading establishes the instrument height, which serves as a reference for subsequent measurements. A...


