As smartphone users know, a sleeping device can still consume the power of a battery. One solution for extending the battery life of wireless devices is to add a wake - up receiver that can tun on a shut - off device.

Angad Rekhi, a university student, and Amin Arabians, an assistant professor have developed a wake - up receiver that turns on a device in response to ultrasonic (超声波的)signals. By working at a significantly smaller wavelength and switching from radio waves to ultrasound, this receiver is much smaller than similar wake - up receivers.

This wake - up receiver has many potential applications, particularly in designing the next generation of networked devices, including the smart devices that can communicate directly with one another without human’s role.

Once attached to a device, a wake - up receiver listens for a unique ultrasonic pattern that tells it when to turn the device on. It only needs a very small amount of power to maintain this constant listening, so it still saves energy.

The designing of these receivers presented a number of challenges. “Miniaturizing wake - up receivers and driving down power consumption while maintaining or extending range are fundamental challenges,” Angad said. “By doing so, the receivers can be small but powerful enough to fit in with the environment.”

By comparison, the ultrasound wake - up receiver requires a battery but has much greater range than the wirelessly powered devices, These two technologies - wireless power and wake - up receivers would likely serve different purposes, but both indicate a turning point in devices that make up the Internet of things.

“In light of a long - promised future where interconnected, autonomous, widespread and remarkable technologies make life easier, the networked devices available now, like video doorbells and app - enabled lights, seem like rather slight advances” the researchers explained. They believe technologies could help cross the gap between the Internet of things as we know it and the Internet of things at their best.

When you imagine a robot, you might picture R2-D2 in Star Wars, but there’s a new robotic system called particle robotics that is changing what it means to be a robot.

Looking like some kids forgot to pick up their toys, the robot is a collection of plastic disks (圆盘). The designers refer to each disk as a “particle”. Alone, a single disk can’t do much of anything. But when working as a system, they become what the designers call a “particle robot” and can do simple tasks.

Scientists behind the project were inspired by nature. In the human body, for example, individual cells (细胞) work together as muscle tissue. Many other types of cells also move together as a group. The robot moves in the same way.

Tiny magnets (磁铁) on the disks’ outer rims (边缘) make them stick together. When one disk expands or shrinks (放大或缩小), it pushes or pulls on its neighbors. When all of those small pushes and pulls add up, suddenly the robot starts to move — very slowly.

Even though the disks don’t communicate directly with each other, they can act as a group. The scientists showed this by fitting sensors on each disk that could recognize light. Then they programmed the disks to expand and shrink faster or slower, depending on how strong the light was. When the researchers shone a bright light, the robot slowly moved toward it — the result of all those individual expansions and shrinks.

Right now, the robot only moves across a smooth surface. It is believed that future robots, such as this one, will continue to copy nature, influencing how they might look and move. There will be more and more biologically based designs.

“We've designed buildings for 100-year floods;” says Kevin Van Den Wymelenberg, director of the Institute for Health in the Built Environment. “But there will be another epidemic or another pandemic - or there might just be another flu season. Let's go ahead and learn to design for the 100-year flu. ”

Public health officials agree that one of the simplest wåys to prevent the indoor spread of the virus is to increase the amount of outside air that comes into our buildings. The simple act of opening a window can meaningfully reduce the concentration of infectious (感染的) particles in the air.

But in many current office buildings, the windows aren't operable. Creating a tight air seal in a building is one of the main strategies used to make buildings more energy-saving. So architects are now wrestling with how to increase air circulation without accelerating energy consumption. One solution, according to Kevin Van Den Wymelenberg, is a special type of window design. This allows outside air to be warmed or cooled, as needed, when it enters the building.

Most current office buildings usually adopt open-plan offices, which are suitable for modern office work. But in time of pandemic, viruses spread easily among workers in the office. Rather than seal employees into individual hard-walled rooms, office designers can preserve the benefits of open-plan offices by fitting airflow systems that clean the air breathed out. For example, vents (通风口) can be installed at the top of the room to pull out the cloud of exhaled (呼出的) air and for fresh air to be delivered along the floor. This type of “biophilic design” can increase productivity and improve physical health.

What all these changes have in common is that they'll happen only if the public continue to focus on indoor health after the acute crisis of the pandemic has passed. In the long run, what's perhaps even more important is making whole environments support human immune function.