China
Africa
Explore chapters and articles related to this topic
IoT and Wearable Sensors for Health Monitoring
Published in Rashmi Gupta, Arun Kumar Rana, Sachin Dhawan, Korhan Cengiz, Advanced Sensing in Image Processing and IoT, 2022
Radhika G. Deshmukh, Akanksha Pinjarkar, Arun Kumar Rana
A magnetometer is a device that measures magnetic dipole moment or magnetic field. Magnetometers measure the direction, strength, or change in the strength of a magnetic field at a specific area. For inertial measurement unit (IMU), they can be used with accelerometers and gyroscopes. All these sensors have three axes, work similarly to a compass, and can help with balance. Magnetometers match them by filtering the motion orientation, but gyroscopes and accelerometers are commonly employed along with them. A magnetometer sensor is shown in Figure 7.4.
Direct Current (dc) Electronics
Published in Dale R. Patrick, Stephen W. Fardo, Electricity and Electronics Fundamentals, 2020
Dale R. Patrick, Stephen W. Fardo
Magnetism has been studied for many years. Some metals in their natural state attract small pieces of iron. This property is called magnetism. Materials that have this ability are called natural magnets. The first magnets used were called lodestones. Now, artificial magnets are made in many different strengths, sizes, and shapes. Magnetism is important because it is used in electric motors, generators, transformers, relays, and many other electrical devices. The earth itself has a magnetic field like a large magnet.
Magnetic and Electrical Properties
Published in Elaine A. Moore, Lesley E. Smart, Solid State Chemistry, 2020
Elaine A. Moore, Lesley E. Smart
Shielding is used either to protect electronic components, for example magnetic lenses in electron microscopes or components of electronic devices, from external magnetic fields or to confine magnetic fields from powerful magnets such as those in MRI machines. One way of doing this is to use a soft magnetic material. The shield acts by providing an alternative path for the magnetic field lines. The shield must be easy to magnetise and have a strong response to the magnetic field. This means it should have a low coercivity and high permeability, that is, a thin, steep hysteresis curve. Widely used materials are nickel–iron alloys. One example is mu-metal., which is 80% Ni, 15.5% Fe, and 4.5% Mo. The alloy is heated to high temperatures to increase the size of the magnetic domains. Most ferromagnetic materials undergo small changes in their shape and dimensions when a magnetic field is applied. This effect can be used in transducers to produce ultrasound waves and is responsible for the hum from transformers. Mu-metal is interesting because its shape and dimensions are virtually unchanged when a magnetic field is applied.
A similarity-based neuro-fuzzy modeling for driving behavior recognition applying fusion of smartphone sensors
Published in Journal of Intelligent Transportation Systems, 2019
Hamid Reza Eftekhari, Mehdi Ghatee
Based on these conditions, the accelerometer, the gyroscope and the magnetometer, which are referred as Inertial Measurement Unit (IMU) sensors, are good options. In contrast to the sensors like GPS, which are turned on by a user or an application, IMU sensors are always activated. In the following, some details are stated from (2700-2017-IEEE Standard for Sensor Performance Parameter Definitions, 2018):Accelerometer: This is a sensor that measures the rate of change of velocity with high accuracy in recording the smallest changes in acceleration and gestures along the three directions of the device. This sensor is a good candidate to determine vehicle acceleration because of its high updating rate. Also, this sensor consumes low energy and it is always turned on.Magnetometer: This sensor measures magnetic field. For example, this sensor can sense the magnetic field around the earth or magnetic objects. By fusion of this sensor and the gyroscope, one can detect the angle between the device and the coordination axis of the base (Renaudin, 2010). This sensor also consumes low energy.Gyroscope: This sensor measures rotation velocity. By this senso, one can detect the rotation of vehicle. Some studies have used this sensor, together with the accelerometer, as a complementary sensor, see e.g., (Bejani & Ghatee, 2018).
Characteristics and potential human health hazards of charged aerosols generated by high-voltage power lines
Published in International Journal of Occupational Safety and Ergonomics, 2019
Joon-Sig Jung, Jae Won Lee, Rajitha Kawshalya Mailan Arachchige Don, Duck Shin Park, Seung Cheol Hong
With the ongoing rapid increase in power consumption, there is a growing trend to install high-voltage power lines (HVPLs) to provide a more stable and efficient power supply. Electronic equipment and power supply infrastructure produce electromagnetic fields, and there have been many disputes on whether these fields may have a harmful effect on the human body. Previous studies have focused mainly on the direct effects of magnetic fields on human health, revealing that they are associated with the release of hormones and higher incidence of malignant diseases such as hormone-dependent cancers, pediatric leukemia and brain tumors. Although many researchers have explored this issue, there is still no definitive evidence to support the association of HVPLs with health problems [1–5]. Despite the results from a great deal of epidemiological and experimental research, little is known about the biological response of the human body to electromagnetic fields.
Static and thermal instability analysis of embedded functionally graded carbon nanotube-reinforced composite plates based on HSDT via GDQM and validated modeling by neural network
Published in Mechanics Based Design of Structures and Machines, 2022
Ali Forooghi, Nasim Fallahi, Akbar Alibeigloo, Hosein Forooghi, Saber Rezaey
The magnetic field is obtained from the moving electric charges. To define how this complex environment is generated by electric charges and currents, the classic Maxwell’s equations are determined in the differential form according to the following relations (Karami et al. 2018): in which where represents the displacement vector. is the two-dimensional (2D) magnetic field vector that is applied to the considered system with the angle θ as follows (Ghorbanpour Arani et al. 2013):