No abstract

Intelligent tires can be used in autonomous vehicles to insure the vehicle safety by monitoring the tire and tire-road conditions using sensors embedded on the tire. These sensors and their wireless communication systems need to be powered by energy sources such as batteries or energy harvesters. The deflection of tires during rotation is an available and reliable source of energy for electric power generation using piezoelectric energy harvesters to feed tire self-powered sensors and their wireless communication systems. The aim of this study is to design, analyze, and optimize a rainbow-shaped piezoelectric energy harvester mounted on the inner layer of a pneumatic tire for providing enough power for microelectronics devices required for monitoring intelligent tires. It is shown that the designed piezoelectric energy harvester can generate sufficient voltage, power, and energy required for a tire pressure monitoring system (TPMS) with high data transmission speed or three TPMSs with average data transmission speed. The effect of the vehicle speed on the voltage and electric energy generated by the designed piezoelectric is also studied. The geometry and the circuit load resistance of the piezoelectric energy harvester are optimized in order to increase the energy harvesting efficiency. It is shown that the optimized rainbow piezoelectric energy harvester can reach the highest power generation among all the strain-based energy harvesters that partially cover the inner layer of the tire.

Summary Basic parameters affecting vehicle safety and performance such as pressure, temperature, friction coefficient, and contact‐patch dimensions are measured in intelligent tires via sensors that require electric power for operation and wireless communication to be synchronized to the vehicle monitoring and control system. Piezoelectric energy harvesters (PEHs) can extract a fraction of energy that is wasted as a result of deflection during rolling of tires, and this extracted energy can be used to power up sensors embedded in intelligent tires. A new design of PEH inspired from Cymbal PEHs is introduced, and its performance is evaluated in this paper. Cymbal PEHs are proven to be useful in vibration energy harvesting, and in this paper, for the first time, the modified shape of Cymbal energy harvester is used as strain‐based energy harvester for the tire application. The shape of the harvester is adjusted in a way that it can be safely embedded on the inner surface of tires. In addition to the high performance, ease of manufacturing is another advantage of this new design. A multiphysics model is developed and validated to determine the output voltage, power, and energy of the designed PEH. The modeling results indicated that the maximum output voltage, the maximum electric power, and the accumulated harvested energy are about 3.5 V, 2.8 mW, and 24 mJ/rev, respectively, which are sufficient to power two sensors. In addition, the possibility is shown to supply power to five sensors by increase in piezoelectric material thickness. The effect of rolling tire temperature on the performance of the proposed PEH is also studied.

Background. Diabetes mellitus (DM) is an interdisciplinary disorder that needs many different specialties’ attention; however, the importance of dermatologists’ knowledge has not been highlighted regarding this issue. As a result, we aim to assess the prevalence and variety of DM skin and nail manifestations in an effort to further acquaint dermatologists and other clinicians with diabetic dermatologic manifestations. Methods. This was a cross-sectional study; subjects who had a diagnosis of DM, attending to the outpatient endocrinology clinics of Rassoul Akram Hospital, Tehran, Iran, were evaluated by one dermatologist for diabetic dermopathy. The results were recorded in prepared data sheets, and general descriptions of DM duration, DM type, DM control, and drug history as well as the demographic data were gathered. Results. Among a total of 255 subjects, the prevalence of one or more identifiable skin conditions was 88.4%. 15.7% of the subjects had nail manifestations. Among cutaneous manifestations, acanthosis nigricans, acral erythema, and onychoschizia showed a significant relationship with the age and disease duration (p<0.05); and knuckle pebbles, eczema, facial erythema, and koilonychias had a meaningful relationship with FBS level and glycated hemoglobin, HbA1c (p<0.05). Conclusion. This study provides an overview that facilitates earlier detection and treatment of DM. Also, this data can help physicians and endocrinologists to visualize DM control level.