Gas sensors sound the smoldering fire alarm

 

Smoke detectors are everywhere, but still thousands of people die in fires annually. Fire gas detectors, which detect carbon monoxide and nitrogen oxide, identify fires at an early stage. Thanks to a new measurement principle developed by Fraunhofer researchers, these costly sensors will soon be inexpensive and ready for the mass market. As the stars twinkle in the sky high above the house, people lie sleeping in their beds. It's just an ordinary night -- and yet, on this night, the slumberers' lives are at stake: A cable is smoldering away and poisonous carbon monoxide spreads unnoticed through the room. The smoke detector doesn't sound the alarm because it responds only to smoke, which is not always produced in a smoldering fire. In short, the room's occupants are in great danger. Reliably detects carbon monoxide Gas sensors could wake people in time and save their lives. Researchers at the Fraunhofer Institute for Physical Measurement Techniques IPM in Freiburg have developed just such a sensor. It recognizes a fire not by its smoke but by the carbon monoxide it emits. Nitrogen dioxide, which is produced a little later in the course of the fire, also triggers the alarm. Even the tiniest amounts of these gases suffice. "The sensors are extremely sensitive, so they respond very early in the fire's development. After all, every second counts," explains Dr. Carolin Pannek, a researcher at the IPM. Life-saving carbon-monoxide sensors of this kind are already available today, but they are too expensive for the mass market. Furthermore, they require maintenance and use a lot of electricity. Commercially available semiconductor gas sensors are cheaper, but can't distinguish between different gases. That's not the case with the new sensor type created by the IPM researchers. "Ours responds only to carbon monoxide and nitrogen dioxide -- it ignores other gases. By using roll-to-roll processing, we can produce the sensors very inexpensively, making it affordable for consumers," confirms Pannek. This is primarily thanks to the dyes at the core of the sensor. Just as a lock opens only with a specific key, each dye responds only to a specific gas. Thus the sensor contains one dye for carbon monoxide and another for nitrogen dioxide. It works by having a small LED shine blue light into a waveguide coated with a polymer into which the dyes have been mixed. The light travels in a zigzag path to the other end of the waveguide, where it meets up with a detector. If the air in the room is normal, the coating glows purple -- which means it absorbs only a small amount of blue light and lets most of the blue light reach the detector. If however there is carbon monoxide in the air, the dye glows yellow. The yellow dye absorbs more blue light -- so the overall amount of light reaching the detector is lower. Below a given threshold value this trips the alarm. To detect nitrogen oxide, the researchers include a second waveguide coated with another dye. Costs slightly more than a smoke detector The researchers were careful to ensure that the sensor could be manufactured cost-effectively in bulk -- after all, no one wants to dig much deeper in their pocket than they would for a conventional smoke detector, even though gas sensors offer significantly more protection. "When mass produced, the sensors will cost about the same as smoke detectors -- and significantly less than the fire gas detectors currently available," Panneck believes. To make their fire gas sensors, the researchers use the same components found in smoke detectors and supplement them with the optical waveguides. The electronics determine the threshold at which the sensor should sound the alarm. To manufacture these components, the researchers have worked together with an industry partner to develop a roll-to-roll process similar to newspaper printing that is capable of printing 15,000 measurement systems on a continuous roll. The process is both suitable for mass production and cost effective. But it will certainly take a few years for the gas sensors to become as ubiquitous in living and bedrooms as smoke detectors are now.   http://www.sciencedaily.com/releases/2015/09/150903081500.htm

Pulses for better posture

 

The implant uses electrical pulses to stimulate muscles. In the future, the unit will be implanted in the patient’s groin area. The picture shows the prototype of the implant. Credit: © Fraunhofer IPMS In an effort to find a better treatment for spinal curvature in children and young people, the EU's "StimulAIS" project is focused on electrostimulation of muscles. Fraunhofer scientists worked with partners from industry and research to develop a prototype implant that would do the job. "Sit up straight!" It's an instruction almost every child has heard some day -- but sometimes being reminded to consider your posture isn't enough: two out of every hundred children and young people between the ages of 10 and 18 suffer from a curvature of the spine. Known as adolescent scoliosis, this growth disorder causes a lasting deformation of the back. These deformations are clearly visible and sufferers often feel disfigured by them. In nine out of ten cases, the exact causes of the spinal curvature are unknown -- what doctors refer to as idiopathic. Recent research suggests that adolescent idiopathic scoliosis, or AIS for short, is caused by a disease of the central nervous system. "According to this theory, the connection between the nerves and the relevant muscles is impaired, but only on one side of the back. When muscles on the healthy side contract, the muscles on the unhealthy side fail to receive the signal to balance the contraction out. This causes the spinal column to twist and buckle," explains Dr. Andreas Heinig from the Fraunhofer Institute for Photonic Microsystems IPMS in Dresden. Building on this theory and working with research and industry partners in Spain and France, Heinig's team has developed a novel approach to treat this form of scoliosis. It makes use of functional electrostimulation, whereby targeted electrical impulses replace the nerve signals that the disease has caused to be either too weak or completely absent. The aim is for the impulses to stimulate the deep muscles along the spinal column so that they build up the necessary counter-contractions to allow symmetrical growth. Within the space of just two years, the interdisciplinary European consortium was able to develop a prototype implant. The implant's principal function is to deliver a pattern of electrical pulses made up of active phases and rest periods, with doctors adjusting the pattern on an ongoing basis to match patients' individual needs. The device's core is implanted in the groin region. It contains circuit boards from which eight one-millimeter electrical cables lead to selected spots along the spinal cord. There, electrodes both stimulate the slack muscles on the side of the body neglected by the brain and monitor their activity. Several additional electrodes lead to the healthy side of the body to record muscle activity there -- providing a set of reference values. An internal control mechanism compares these differing datasets with a view to constantly adjusting the muscle stimulation in line with the progress of the treatment. It takes 50 pulses per second to stimulate the rotator muscles -- and these pulses must be delivered over a long period of time. A typical training program involves six to eight hours of treatment every day, preferably during the night or at other quiet times, with several waves of muscle stimulation, each lasting a maximum of ten seconds, separated by at least ten minutes of rest. Tailoring stimulation and resting times to the muscles The battery the implant uses to carry out the standard program lasts around nine days before it needs to be recharged. Recharging takes roughly 90 minutes and is realized wirelessly via an inductive coupling. The data, too, are sent wirelessly from the implant to an external reader device -- and vice versa. This makes it possible both to track the muscle activity measured in the body and to tailor each AIS patient's stimulation and resting times on an ongoing basis depending on the state of their muscles. "Our partners in Valencia were responsible for designing the relevant system. Should the implant be given to children with AIS one day, it will be their attending physician who operates the reader device," says Heinig. Initial testing showed that the technology works in principle, with researchers sending data in both directions without a hitch. The muscle activation worked as planned, too. To position the fine electrodes in exactly the right place in the deep muscles along the spinal column, French company Synimed (another member of the consortium) developed special precision surgical instruments. Compared to today's therapies, which oblige children to wear a corset or which involve operations to fuse the spine with metal plates and pins, the concept of functional electrostimulation is superior: this minimally invasive implant-based treatment not only promises to prevent the worst, but also opens the way to achieving a lasting correction of deformations. Whether the concept proves itself in practice is something only time will tell, Heinig stresses: "We have clearly shown that this form of therapy is technically feasible. Now it's up to future clinical studies to demonstrate that the therapy is medically effective and can cure or at least alleviate scoliosis." Story Source: The above post is reprinted from materials provided by Fraunhofer-Gesellschaft. Note: Materials may be edited for content and length.

Citações ao ribombar dos trovões

 

Stress management: Know your triggers

 

Your response to the demands of the world determines your stress level. Take time to consider common stressors and how they affect you . By Mayo Clinic Staff The kids are screaming, the bills are due and the pile of papers on your desk is growing at an alarming pace. It's undeniable — life is full of stress. Understanding the types and sources of stress — short term and long term, internal and external — is an important part of stress management. So what stresses you out? Two main types of stress Stress is your body's reaction to the demands of the world. Stressors are events or conditions in your surroundings that may trigger stress. Your body responds to stressors differently depending on whether the stressor is new — acute stress — or whether the stressor has been around for a longer time — chronic stress. Acute stress Also known as the fight-or-flight response, acute stress is your body's immediate reaction to a perceived threat, challenge or scare. The acute-stress response is immediate and intense, and in certain circumstances it can be thrilling. Examples of acute stressors include having a job interview or getting a speeding ticket. A single episode of acute stress generally doesn't cause problems for healthy people. However, severe acute stress can cause mental health problems, such as post-traumatic stress disorder, and even physical difficulties such as a heart attack. Chronic stress Mild acute stress can actually be beneficial — it can spur you into action, motivate and energize you. The problem occurs when stressors pile up and stick around. This persistent stress can lead to health problems, such as headaches and insomnia. The chronic-stress response is more subtle than is the acute-stress response, but the effects may be longer lasting and more problematic. Effective stress management involves identifying and managing both acute and chronic stress. Next References See more In-depth   http://www.mayoclinic.org/healthy-lifestyle/stress-management/in-depth/stress-management/art-20044151