Mandeep Kaur

The Editorial Office and Editorial Board of Sensors are jointly issuing a resolution and removal of the Journal Notice linked to this article

Optical devices are frequently being used in medical applications to image lesions and malignancies, and to assist with surgical procedures. The advances in micro-electro-mechanical systems (MEMSs) and optics led to the fabrication of flexible endoscopes as small as a few millimeters in diameter. The design of a sub-millimeter sized optical fiber scanner is presented in this paper. The proposed scanner consisted of a vibrating optical fiber that carried the laser light to the targeted imaging sample. The desired vibratory motion of the scanning device was obtained using a U-shaped electrothermal actuator where the asymmetry in the actuator’s arm length caused the free end of the actuating device to bend allowing a bidirectional motion at its free end. The periodic square current wave passing through the actuator caused it to bend in a timely manner. By matching the signal frequency to the resonant frequency of the cantilever fiber and placing the cantilever appropriately relative to the actuator, the distal end of the fiber was allowed to follow a Lissajous scan. In optical scanners, the Lissajous scan pattern is normally obtained using a pair of actuators. This paper presents the design of a scanner providing a 2D Lissajous scan using a single actuator. Such a technique can provide basis for the development of sub-millimeter sized forward-viewing endoscopic catheters, whereas the smallest single fiber endoscope has a diameter of 1.2 mm. In the medical field, such a device has the potential to image small cavities of the body increasing the diagnostic yield of the medical procedures.

Optical scanners are used frequently in medical imaging units to examine and diagnose cancers, assist with surgeries, and detect lesions and malignancies. The continuous growth in optics along with the use of optical fibers enables fabrication of imaging devices as small as a few millimeters in diameter. Most forward viewing endoscopic scanners contain an optical fiber acting as cantilever which is vibrated at resonance. In many cases, more than one actuating element is used to vibrate the optical fiber in two directions giving a 2D scan. In this paper, it is proposed to excite the cantilever fiber using a single actuator and scan a 2D region from its vibrating tip. An electrothermal actuator is optimized to provide a bidirectional (horizontal and vertical) displacement to the cantilever fiber placed on it. A periodic current, having a frequency equal to the resonant frequency of cantilever fiber, was passed through the actuator. The continuous expansion and contraction of the actuator enabled the free end of fiber to vibrate in a circle like pattern. A small change in the actuation frequency permitted the scanning of the area inside the circle.

Endoscopes are used routinely in modern medicine for in-vivo imaging of luminal organs. Technical advances in the micro-electro-mechanical system (MEMS) and optical fields have enabled the further miniaturization of endoscopes, resulting in the ability to image previously inaccessible small-caliber luminal organs, enabling the early detection of lesions and other abnormalities in these tissues. The development of scanning fiber endoscopes supports the fabrication of small cantilever-based imaging devices without compromising the image resolution. The size of an endoscope is highly dependent on the actuation and scanning method used to illuminate the target image area. Different actuation methods used in the design of small-sized cantilever-based endoscopes are reviewed in this paper along with their working principles, advantages and disadvantages, generated scanning patterns, and applications.

The growth and development of optical components and, in particular, the miniaturization of micro-electro-mechanical systems (MEMSs), has motivated and enabled researchers to design smaller and smaller endoscopes. The overarching goal of this work has been to image smaller previously inaccessible luminal organs in real time, at high resolution, in a minimally invasive manner that does not compromise the comfort of the subject, nor introduce additional risk. Thus, an initial diagnosis can be made, or a small precancerous lesion may be detected, in a small-diameter luminal organ that would not have otherwise been possible. Continuous advancement in the field has enabled a wide range of optical scanners. Different scanning techniques, working principles, and the applications of endoscopic scanners are summarized in this review.

Medical professionals increasingly rely on endoscopes to carry out many minimally invasive procedures on patients to safely examine, diagnose, and treat a large variety of conditions. However, their insertion tube diameter dictates which passages of the body they can be inserted into and, consequently, what organs they can access. For inaccessible areas and organs, patients often undergo invasive and risky procedures—diagnostic confirmation of peripheral lung nodules via transthoracic needle biopsy is one example from oncology. Hence, this work sets out to present an optical-fiber scanner for a scanning fiber endoscope design that has an insertion tube diameter of about 0.5 mm, small enough to be inserted into the smallest airways of the lung. To attain this goal, a novel approach based on resonance thermal excitation of a single-mode 0.01-mm-diameter fiber-optic cantilever oscillating at 2–4 kHz is proposed. The small size of the electro-thermal actuator enables miniaturization of the insertion tube. Lateral free-end deflection of the cantilever is used as a benchmark for evaluating performance. Experimental results show that the cantilever can achieve over 0.2 mm of displacement at its free end. The experimental results also support finite element simulation models which can be used for future design iterations of the endoscope.

Microgrid (MG) has emerged as a new paradigm for effective integration of intermittent Renewable Energy Sources (RESs) and to meet increase in energy demand. With the advancement in control and telecommunication technology, consumers can participate in the energy market. But with the restructuring of power market, MG faces the problem of developing optimal bidding strategies to maximize its profit. In this paper, optimization based self-scheduling and strategy for bidding of MG in day ahead energy market is proposed to maximize utilities benefit. A low voltage 14-bus system having generating resources like solar, pumped hydro, wind and diesel generator including different types of consumers is considered for investigation. The role of consumers has been investigated for the system scheduling and in bidding process. The analysis shows that the consumers can play vital role in determining the optimal scheduling and bidding strategy of MG for participation in the energy market which not only maximizes its benefit but also reduces the burden on grid.