다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

More than a decade of research in the field of thermal, motion, vibration and electromagnetic radiation energy harvesting has yielded increasing power output and smaller embodiments. Power management circuits for rectification and DC-DC conversion are becoming able to efficiently convert the power from these energy harvesters. This paper summarizes recent energy harvesting results and their power management circuits.

Micropower energy harvesting

Linear electric actuators and generators (LEAGs) are electromagnetic devices which develop directly short-travel progressive (or oscillatory) linear motion. Machine tool sliding tables, pen recorders and free piston power machines are typical industrial applications for LEAGs. Their recent revival in applications in compressors, pumps, electromagnetic valve actuators, active shock absorbers, vibrators, etc. Prompts this review, which presents main LEAGs configurations, their principles of operations, comparative performance evaluation, motion control and existing as well as potential applications.

Linear Electric Actuators and Generators

A petroleum well has an electronic module and a number of sensors which communicate with the surface using the tubing string and casing as conductors. Induction chokes at the surface and downhole electrically impede AC flow through the (tubing or casing if so configured) with the resulting voltage potential useful for power and communication. A high bandwidth, adaptable spread spectrum communications system is used to communicate between the downhole electronics module and a surface master spread spectrum modem. Downhole sensors, such as pressure, temperature, acoustic and seismic sensors accurately assess downhole physical conditions. In a preferred form, the electronics module and sensors are wireline insertable and retrievable into a side pocket mandrel in the tubing string. Permanent downhole sensors that can communicate with the surface allow such diverse applications as optimizing well and field performances, monitoring and assessing the geophysics of the fomrations around the well, assessing well and reservoir reserves, assessing reservoir conditions.

Petroleum well having downhole sensors, communication and power

A system and method of communicating among devices via a piping structure using at least one induction choke about the piping structure to route a time-varying current carrying communication signals between the devices. A communications system comprises a piping structure, a first communication device, a second communication device, and an induction choke. The piping structure comprises a first location, a second location, and an electrically conductive portion extending between the first and second locations. The first and second locations are distally spaced along the piping structure. The first and second communication devices are each electrically connected to the electrically conductive portion of the piping structure along the first location and second location, respectively, and each is adapted to send and receive communication signals via time-varying current. The induction choke is located about an electrically choked portion of the electrically conductive portion of the piping structure, such that the induction choke is adapted to route time-varying current within the piping structure between the electrical connection location for the first communication device and the electrical connection location for the second communication device, and such that the first communication device can communicate with the second communication device via the piping structure. A preferred application of the present invention is a well for producing petroleum products (e.g., oil, natural gas), comprising a communication system as described above.

Permanent downhole, wireless, two-way telemetry backbone using redundant repeaters

The purpose of this study is to demonstrate the energy harvesting of power-line magnetic noise. To the best of the authors' knowledge, no research has yet been carried out to confirm this possibility. In this paper, we present a simple circuit design model, and confirm its validity by experimental results. For small self-sufficient devices in a wireless sensor network, the target energy level is 1 mW. We prepare an energy harvesting module with an air-core coil and resonant capacitor. From experimental and simulated results, we investigate the desired conditions for harvesting 1 mW from a uniform magnetic field of 60 Hz. Through experimental results with iron cores, the benefits and drawbacks of the use of a magnetic core are also discussed. With our best harvested module, we successfully demonstrated the energy harvesting of 6.32 mW from a magnetic field of 21.2 μT at 60 Hz. If the usable magnetic flux density increases tenfold, the harvesting energy increased 100-fold. If the magnetic flux density is at an acceptable level in a public space of 200 μT at 60 Hz, the harvesting power density becomes 130 μW/cm3. This value is comparable to the value of an energy harvesting module of a light source during a cloudy day.

/pdf/energy-harvesting-of-magnetic-power-line-noise-1nddjm3bts.pdf

Energy Harvesting of Magnetic Power-Line Noise

This paper proposes an eddy-current testing (ECT) probe composed of a spin-valve giant magnetoresistance (SV-GMR) sensor and a meander coil for the inspection of bare printed circuit board. The SV-GMR sensor serves as a magnetic sensor for the ECT probe to sense the variation of the magnetic field distribution occurred on the printed circuit board. The SV-GMR sensor is used specifically to detect the changing magnetic field distribution occurred at the defect point. The characteristics of the proposed probe are discussed in this paper. The comparisons of signal-to-noise ratios obtained from ECT probe with SV-GMR sensor and with solenoid coil verify that the applying of SV-GMR sensor to the ECT probe can improve the PCB inspection results.

/pdf/eddy-current-testing-probe-with-spin-valve-type-gmr-sensor-rotfev9q6r.pdf

Eddy-current testing probe with spin-valve type GMR sensor for printed circuit board inspection

This paper discusses the effect of inductive coil shape on the sensing performance of a linear displacement sensor. The linear displacement sensor consists of a thin type inductive coil with a thin pattern guide, thus being suitable for tiny space applications. The position can be detected by measuring the inductance of the inductive coil. At each position due to the change in inductive coil area facing the pattern guide the value of inductance is different. Therefore, the objective of this research is to study various inductive coil pattern shapes and to propose the pattern that can achieve good sensing performance. Various shapes of meander, triangular type meander, square and circle shape with different turn number of inductive coils are examined in this study. The inductance is measured with the sensor sensitivity and linearity as a performance evaluation parameter of the sensor. In conclusion, each inductive coil shape has its own advantages and disadvantages. For instance, the circle shape inductive coil produces high sensitivity with a low linearity response. Meanwhile, the square shape inductive coil has a medium sensitivity with higher linearity.

https://www.mdpi.com/1424-8220/11/11/10522/pdf

Effect of inductive coil shape on sensing performance of linear displacement sensor using thin inductive coil and pattern guide.

When measuring torque, there are many demands, such as non-contact to the shaft, a small size, and a simple installation. Other critical factors include, special processing in the shaft, which is not required, and being cost-effective. Therefore, we have proposed a new magnetostrictive type torque sensor [IEEE Trans. Mag. 35 (1999) 4503] (MTS) for a steering shaft using an inverse magnetostrictive effect. Generally, a magnetostrictive type torque sensor has a large hysteresis property. With this sensor, we have shown that the hysteresis can be drastically decreased, if the excitation magnetic field double the value or more of the coercive force of the shaft material is applied.

New magnetostrictive type torque sensor for steering shaft

The comparative evaluation based on the power speed density of several types of portable Permanent Magnet Generator (PMG) considered for agricultural applications is presented. These generators are purposely designed to be used in agriculture sectors and thereby it should be of lightweight, small in size and ease to use. Six difierent generator topologies are developed for investigation of such purposes. A number of design parameters are considered to analyze the performance characteristics for each type of developed PMG. Based on the power speed density factor that is used to describe better generator performance, the suitable PMG for the agricultural application is identifled through a comprehensive evaluation.

/pdf/comparative-evaluation-on-power-speed-density-of-portable-lp6f7bporb.pdf

Hiroyuki Wakiwaka

Papers

Energy Harvesting of Magnetic Power-Line Noise

Eddy-current testing probe with spin-valve type GMR sensor for printed circuit board inspection

Effect of inductive coil shape on sensing performance of linear displacement sensor using thin inductive coil and pattern guide.

New magnetostrictive type torque sensor for steering shaft

Comparative Evaluation on Power-Speed Density of Portable Permanent Magnet Generators for Agricultural Application