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Wildfires In just seconds, a spark or even the sun's heat alone sets off an extremely large fire. The wildfire quickly spreads, consuming the thick, dried-out plants and almost everything else in its path. What was once a forest becomes a virtual powder keg of untapped fuel. In a seemingly instantaneous burst, the wildfire overtakes thousands of acres of surrounding land, threatening the homes and lives of many in the vicinity. Fire Starters On a hot summer day, when drought conditions peak, something as small as a spark from a train car's wheel striking the track can ignite a raging wildfire. Sometimes, fires occur naturally, ignited by heat from the sun or a lightning strike. However, the majority of Wildfires are the result of human carelessness. Common causes for wildfires include: Arson Campfires Discarding lit cigarettes Improperly burning debris Playing with matches or fireworks Prescribed fires Everything has a temperature at which it will burst into flames. This temperature is called a material's flash point. Wood's flash point is 572 degrees Fahrenheit(300 ℃). When wood is heated to this temperature, it releases hydrocarbon gases that mix with oxygen in the air, combust and create fire. There are three components needed for ignition and combustion to occur. A fire requires fuel to burn, air to supply oxygen, and a heat source to bring the fuel Up to ignition temperature. Heat, oxygen and fuel form. the fire triangle. Firefighters often talk about the fire triangle when they are trying to put out a blaze. The idea is that if they can take away any one of the pillars of the triangle, they can control and ultimately extinguish the fire. After combustion occurs and a fire begins to burn, there are several factors that determine how the fire spreads. These three factors include fuel, weather and topography. Depending on these factors, a fire can quickly fizzle or turn into a raging blaze that scorches thousands of acres. Fueling the Flames Wildfires spread based on the type and quantity of fuel that surrounds it. Fuel can include everything from trees, underbrush and dry grassy fields to homes. The amount of flammable material that surrounds a fire is referred to as the fuel load. Fuel load is measured by the amount of available fuel per unit area, usually tons per acre. A small fuel load will cause a fire to burn and spread slowly, with a low intensity. If there is a lot of fuel, the fire will burn more intensely, causing it to spread faster. The faster it heats up the material around it, the faster those materials can ignite. The dryness of the fuel can also affect the behavior. of the fire. When the fuel is very dry, it is consumed much faster and creates a fire that is much more difficult to contain. Here are the basic fuel characteristics that decide how it affects a fire: Size and shape Arrangement Moisture content Small fuel materials, also called flashy fuels, such as dry grass, pine needles, dry leaves, twigs and other dead brush, burn faster than large logs or stumps(this is why you start a fire with kindling rather than logs). On a chemical level, different fuel materials take longer to ignite than others. But in a wildfire, where most of the fuel is made of the same sort of material, the main variable in ignition time is the ratio of the fuel's total surface area to its volume. Since a twig's surface area is much larger than its volume, it ignites quickly. By comparison, a tree's surface area is much smaller than its volume, so it needs more time to heat up before it ignites. As the fire progresses, it dries out the material just beyond it—heat and smoke approaching potential fuel causes the fuel's moisture to
A.
Y
B.
N
C.
NG
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【单选题】患者散发烂苹果样气味,常提示为()
A.
水肿病晚期
B.
消渴病危重
C.
失血重证
D.
脏腑败坏
E.
瘟疫病
【单选题】操纵控制器的类型很多,按操纵方式划分可分为( ):
A.
手动控制器和脚动控制器
B.
手动控制器和声动控制器
C.
开关控制器和转换控制器
D.
调整控制器和转换控制器
【简答题】Python 中定义函数的关键字是 。
【单选题】患者散发烂苹果样气味 , 常提示为 ()
A.
水肿病晚期
B.
消渴病危重期
C.
 失血重证
D.
脏腑败坏
【单选题】Python中定义函数的关键字是:
A.
function
B.
def
C.
fun
D.
define
【单选题】It doesn’t make any difference how we get there because we’re going to be late________.
A.
however
B.
therefore
C.
anywhere
D.
anyway
【单选题】在页面内绘制一个矩形后,在属性栏中对这个矩形进行输入缩放比例,在变换的同时,这个矩形会自动复制,如果要取消这项功能,应该怎样设置
A.
在属性栏中击右键,选择变换,在变换面板中将“应用于再制”按钮弹起
B.
在属性栏中击右键,选择变换,在变换面板中将“相对于对象”按钮弹起
C.
在属性栏中,将变换比例后的小锁点击弹起
D.
在选项的工作区中进行设置
【单选题】操纵控制器的类型很多,按操纵方式划分可分为:
A.
调整控制器和转换控制器
B.
开关控制器和转换控制器
C.
手动控制器和脚动控制
D.
手动控制器和声动控制器
【单选题】We're simply going to have to do it, __________ how much it costs.
A.
regardless of
B.
worthy of
C.
/
D.
/
【单选题】如图所示,图中左侧的气球上标志进行的封套变形,“样式”项为凸出,弯曲数值为46%。将操作记录为动作并对右侧蓝色气球上的标志应用。希望弯曲数值可以在播放动作的时候自行设定,请问以下说法正确的是?()
A.
对于需要设置参数的操作,播放动作时会自动弹出对话框,无需录制动作时插入项目
B.
无法在录制动作时实现,需要插入暂停,然后手动执行命令后继续执行动作
C.
录制动作时,插入菜单项目,选择菜单中的封套变形命令
D.
录制动作时,在封套变形动作前面插入一个允许继续的暂停
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