Ease of miniaturization, and less or no maintenance, among other advantages, have pushed towards replacement of conventional batteries with energy harvesters in particular, vibratory energy harvesters. In the recent years, nonlinearity has been intentionally introduced into the otherwise linear energy harvesters in the hope of increasing the frequency bandwidth and power density. However, funda...

In this study, we fabricated piezoelectric energy harvesters composed of lead-free (K,Na)NbO3 (KNN) thin films and compared the power generation performance with PZT-thin film energy harvesters. Both of the piezoelectric thin films were deposited on Pt/Ti/Si cantilevers by rf-sputtering. The KNN and PZT thin films had perovskite structure, and showed the relative dielectric constants of 744 and...

Pyroelectric harvesters convert time-dependent temperature variations into electric current. The appropriate geometry of the pyroelectric cells, coupled with the optimal period of temperature fluctuations, is key to driving the optimal load resistance, which enhances the performance of pyroelectric harvesters. The induced charge increases when the thickness of the pyroelectric cells decreases. ...

UNLABELLED The various kinds of work may interfere in the laborer's quality of sleep. Among the factors, the unemployment caused by the period between the coffee harvests on the agriculture of South Minas may influence the appearance of anxiety and depression symptoms, and it may cause impairments to the quality of life and changes in the rural laborers' pattern of sleep. OBJECTIVE To apprais...

Once local expert knowledge regarding the harvesting of various non-timber forest products (NTFPs) is lost, it is difficult to recover. We investigated whether the knowledge of expert forest harvesters can be used to determine the habitat distribution and harvesting sites of three popular edible wild ferns, i.e., ostrich fern (Matteuccia struthiopteris), bracken (Pteridium aquilinum), and royal...

Energy harvesting has become an increasingly important topic thanks to the advantages in renewability and environmental friendliness. In this paper, a comprehensive study on contemporary portable wind energy harvesters has been conducted. The electrical power generation methods of portable wind energy harvesters are surveyed in three major groups, piezoelectric-, electromagnetic-, and electrost...

The authors suspected that suspended onion particles contributed to corneal ulcers in onion harvesters in southern Taiwan. In the present study, the authors used manikins to study suspended onion particles in fields in an effort to simulate typical conditions experienced by onion harvesters. An animal eye-exposure simulation study was also performed by the authors, who impacted suspended soil g...

The sickle is still an ultimate choice hand tool for harvesting the new variety of rice. This preference continues. The sickles used by Balinese harvester are usually nonserrated. The sharpness of nonserrated sickles is reduced quickly, so the harvester needs time to sharpen them frequently, which mean time loss and productivity reduction. To solve this problem, research has been conducted usin...

FACULTY OF PHYSICAL AND APPLIED SCIENCES SCHOOL OF ELECTRONICS AND COMPUTER SCIENCE Doctor of Philosophy DESIGN, MODELLING AND CHARACTERISATION OF IMPACT BASED AND NON-CONTACT PIEZOELECTRIC HARVESTERS FOR ROTATING OBJECTS

Energy consumption is a perennial issue in the design of wireless sensor networks (WSNs) which typically rely on portable sources like batteries for power. Recent advances in ambient energy harvesting technology have made it a potential and promising alternative source of energy for powering WSNs. By using energy harvesters with supercapacitors, WSNs are able to operate perpetually until hardwa...