This paper addresses the challenge of mobile robot navigation in indoor environments. There is a critical need for cost-effective, reliable, and fairly accurate solutions to meet the demands of indoor robotic applications. Currently, researchers are exploring various approaches for this problem. The one we are presenting in this paper is based on QR (Quick Response) codes to provide location references for mobile robots. The mobile robot is equipped with a Smartphone that is programmed to detect and read information on QR codes that are strategically placed in the operating environment of the robot. The mobile robot can perform the autonomous run throughout the guide route by using real-time QR code recognition. The lab information on QR code is played to the visitors using Text-to-Speech provided through Android device. Ultrasonic range sensors which can detect objects and measure distances with high accuracy are used to implement the wallfollowing and obstacle-avoidance behaviors. The collected sonar range information by ultrasonic range sensors is processed by a microcontroller that autonomously controls a tour guide robot. An algorithm based on a proportional-integral-derivative (PID) control is applied to the tour guide robot to perform more accurate robot motion control. A Bluetooth technology is used to send stored information on QR codes from the Smartphone to the tour guide robot wirelessly. The experimental setup of the tour guide robot along with the successful implementation of the efficient method for a navigation technique is presented.

Bypassing transient current through copper (Cu) stabilizer layers reduces heat generation and temperature rise of high-temperature superconducting (HTS) conductors, which could protect HTS cables from burning out during transient conditions. The Cu layer connected in parallel with HTS tape layers impacts current distribution among layers and variations of phase resistance in either steady-state or transient conditions. Modeling the multilayer HTS power cable is important for transient studies. However, existing models of HTS power cables have only proposed HTS cables without the use of a Cu-former layer. To overcome this problem, the authors proposed a multilayer HTS power cable model that used a Cu-former layer in each phase for transient study. It was observed that resistance of the HTS conductor increased significantly in the transient state due to a quenching phenomenon, which made the transient current mainly flow into the Cu-former layers. Since resistance of the Cu-former layer has a significant impact on the transient current, detailed modeling of the Cu-former layer is described in this study. The feasibility of the developed HTS cable model is evaluated in the PSCAD/EMTDC program.

No abstract

No abstract

The effect of hydrogenation on the room-temperature 1.54 μm Er3+ photoluminescent properties of erbium-doped silicon-rich silicon oxide thin films is investigated. Two samples with 7 and 1 at. % excess silicon and 0.4 at. % erbium were prepared by electron cyclotron resonance plasma-enhanced chemical vapor deposition of SiH4 and O2 with cosputtering of erbium and subsequent rapid thermal anneal at 900 °C. Hydrogenation by exposure to D plasma doubles the 1.54 μm Er3+ luminescence intensity from the high excess silicon content sample but halves that from the low excess silicon content sample. The lifetimes and excitation power dependence of Er+ luminescence show that hydrogenation primarily affects the active erbium fraction, increasing it in case of the high excess silicon sample but decreasing it in case of the low excess silicon content sample. With proper treatments, Er3+ luminescence lifetime of over 7 ms is obtained.