Emergency Mask Pod (面罩舱) is a plastic, 3D-printed and football-shaped case that contains a mask that protects the lungs of someone trapped in a fire until they were rescued. Alexis got the idea for the Emergency Mask Pod after hearing that a mother had thrown her baby out of the second floor window of their smoke-filled apartment during a fire in the building. The family was trapped in their apartment by the smoke.

Alexis wondered whether there was a means for people waiting outside, such as neighbors and first responders, to deliver smoke masks to people trapped in the second floors of burning buildings. Her research showed that there was no such delivery system, so Alexis set about to invent one.

First, she found a small, lightweight smoke mask. The next step was to develop a way to launch or throw the mask up into an open second-story window. Alexis built several different pods, which were tested by local firefighters. Each pod was cast into a second story window more than 290 times by a total of 37 firefighters. The football-shaped pod, which Alexis printed on her MakerBot 3D printer, was the clear winner, with an accuracy rate of over 70 percent.

The firefighters testing the Emergency Mask Pod told her that it is needed by firefighters arriving at the scene of a fire. They told Alexis that when they find people trapped inside, they wish they could give them some form of relief so they can breathe safely while firefighters try to reach them. A smoke delivery system could be used to provide that relief.

The Emergency Mask Pod requires no special equipment, training, or permits; people at the scene of a fire could help fire victims (受害者) trapped inside smoky rooms without hesitation. EMTs, police officers, and firefighters could keep the mask and EM Pod in their vehicles and apartment complexes could store them in approachable places like community centers. The mask could easily be retrieved by victims and put on, giving them precious time for firefighters to rescue them and potentially saving hundreds or thousands of lives.

If someone created a flying machine able to track you down by listening for your voice, you might be terrified. But what if you were trapped in ruins after a natural disaster and first responders couldn’t locate you? Maybe then a human-seeking drone (无人机) wouldn’t be such a terrible idea. That concept is the focus for engineers at Germany’s Fraunhofer FKIE Institute, who’ve built a drone to find people by detecting human screams.

The human seeking drone would be ideal for post-disaster situations, such as earthquakes, hurricanes and wildfires,” said Macarena Varela, one of the lead engineers. “They could hover over an area that rescue crews have difficulty getting to and locate exactly where people may be trapped.”

Locating people by sound presents its share of challenges. An auditory system would need to tell human cries from sounds that often happen in nature, such as animal calls and wind. It might also need to recognize patterns associated with kicking, clapping or other ways people try to get the attention of rescue teams.

Engineers took those situations into account when building out their concept drone. They recorded themselves screaming, tapping and creating other noises that might be a sign of people in trouble. Then, they analyzed each sound frequency to find common signatures and used those to train artificial intelligence software. They also worked to remove the noise created by the drone and other environmental sounds.

Once the software part was completed, the team placed tiny digital microphones under the drone and used signal processing techniques that enabled them to track where human noises are coming from. The microphones also enhanced the volume and clearness of the speech. So far, they have conducted successful open field experiments finding that the drone can estimate a victim’s location within a few seconds of picking up sound.

Next, they would like to add a higher frequency microphone to a drone to acquire more audio sound signals. The idea is to pick up noises from hundreds of meters away, Varela said. In the real world, victim’s location date might one day be sent wirelessly to emergency crews carrying a tablet.

It is hard to say the first day of school in the United States because when the first day of school is and what happens on the first day of school usually are different by districts (地区).

The first day of school for many school districts in different states is on the day after the first Monday in September. In some other school districts, school begins in mid-to-late August. For example, the Denver, Colorado schools go back in mid-August and schools in Cleveland, Ohio start back usually one week before the first Monday in September. The Boston, Chicago, New York City and San Diego schools start back on the Tuesday or Wednesday after the first Monday in September.

Schools in Cleveland, Ohio used to start the school year on the day after the first Monday in September, but in the 1976—1977 and 1977—1978 academic years, the school year was affected by several bad snowstorms, extremely cold. In the 1978—1979 school year, the Ohio Department of Education moved the start of the year to late August, one week before the first Monday in September. This went into effect in the 1980—1981 school year.

In most school districts in Utah, the school year starts between August 25 and August 30, and goes until the last week of May or the first week in June next year.

In American high schools, the freshmen class usually goes back one or two days before the rest of the school body for an orientation (迎新) period. An orientation period helps the freshmen get familiar with their new school, its rules, and surroundings.

In some schools, the freshmen classes have their photographs taken for identification purposes. Some high schools have tried to make the first week of school fun for incoming freshmen.