Self-advancing, hydraulically-powered supports temporarily hold up the roof while coal is extracted. When the coal has been extracted from the area, the roof is allowed to collapse. Over 75% of the coal in the deposit can be extracted from panels of coal that can extend 3km through the co...
Coal mining satiates roughly 1/4 of our global energy demands, and it is coal that has powered America’s power needs for decades. This is not only true of the US; Europe has also reaped the rich benefits of coal. The industrial revolution was only possible due to the utilization of coa...
and, as is so common with failures in the lab, he ended up with a nasty, black solid residue in the bottom of his flask. While cleaning the flask, he found that the mess contained a purple-colored compound that was soluble in alcohol. ...
Through pure serendipity, Perkins had discovered the first aniline coal-tar dye. But it was by seizing the serendipitous opportunity that Perkins became the modern chemical industry founding father. The list of serendipitous...
There is a blackboard in the front of the classroom. 教室里前部有一块黑板。 18. find, find out 两者都有“发现”的意思,但语义有差别。 find有偶然发现某物的意味。 如: He found a bag on the floor. 他发现地板上有个书包。 find out指“经过,探听,询问”,指调查之后的“发现”或“弄清楚”...
The trend for bioethanol stoves in Africa is slowly gaining traction, driven by the need for cleaner cooking solutions. Traditional stoves using wood or charcoal contribute to indoor air pollution and health problems, making bioethanol stoves an attractive alternative due to their cleaner combustion. ...
aAs teachers,we should concern ourselves with what is said in class,not what we think ought to be said. 作为老师,我们应该有关自己与什么在类说,没有什么我们认为应该说。[translate] aExplain how coal is a store of solar energy 解释怎么煤炭是太阳能商店[translate]...
The world is getting warmer. Human activity is the main reason for this, the United Nations (UN) said. For example, people use fossil fuels (化石燃料)like coal and oil. They give off a lot of greenhouse gases (温室气体)(especially CO2) into the air. This warms the earth. As a ...
As mentioned earlier, gasoline begins as crude oil, a fossil fuel. Fossil fuels are the carbon-rich remnants of dead animals and plants that have been pressurized and heated at high temperatures underground for millions of years. The end product is crude oil, natural gas or coal. ...