Pollution Maintenance Techniques in Coastal High Voltage Installations

Pollution of outdoor high voltage insulators is a common problem for utilities, with a considerable impact to power system reliability. In an effort to prevent possible flashovers due to pollution, many methods have been applied, aiming to improve the insulation performance, either by suppressing the formation of surface conductivity or by increasing the possible insulation level. In the case of substations, the selection of the appropriate technique is complex due to certain issues correlated to the nature of the installation. In this paper, several techniques usually implemented by utilities, are investigated based on the experienced gained in the case of Crete, a Greek island in southern Europe, where due to the coastal development of the power system, the majority of high voltage installations are exposed to intense marine pollution. The technique of coating insulators with Room Temperature Vulcanized Silicone Rubber (RTV SIR) has proved rather efficient and therefore is presented extendedly. Correlation of the material behaviour with environmental conditions is discussed and results from long term monitoring, including environmental parameters and leakage current measurements, in a 150 kV Substation are presented. It is shown that RTV SIR coatings have remarkably suppressed surface activity and that porcelain insulators exhibit different activity period when coated

Isokinetic Evaluation of the Elbow Joint at 45° and 80° of Shoulder Abduction

Since Hislop and Thistle published the first reports on isokinetic exercise, a lot of progress has been made towards the use of isokinetic exercise and isokinetic evaluation of muscle and joint performance in sports and orthopedic physical therapy. Cybex II+ with the Cybex Data Reduction Computer is one of the most widely used isokinetic systems for research and rehabilitation purposes. There are more than 500 published works describing the use of Cybex in various applications, Many investigations have used the Cybex isokinetic system to develop normative data on torque and work measurements of various muscle groups. Normative data are valuable to clinicians in the evaluation of the severity of an injury in terms of muscle performance deficits. In addition, such data provide physical therapists with objective data in setting rehabilitation goals, and enabling sports medicine experts to identify functional deficiencies during screening of athletes. There is a limited number of published works that have developed normative data for elbow flexor and extensor muscle groups. While there is some information about peak torque and agonist-antagonist ratios, minimal information is available about torque acceleration energy, work endurance ratios, average power and flexion-extension total work ratios. The purpose of this study was to examine the effects of 450 and 800 of shoulder abduction on torque and work measurements of the elbow joint. In addition, normative data for elbow flexion and extension at both arm positions (testing positions suggested by Cybex) were developed

A Labview Based Leakage Current Monitoring System For HV Insulators

In this paper, a Labview based leakage current monitoring system for High Voltage insulators is described. The system uses a general purpose DAQ system with the addition of different current sensors. The DAQ system consists of a chassis and hot-swappable modules. Through the proper design of current sensors, low cost modules operating with a suitable input range can be employed. Fully customizable software can be developed using Labview, allowing on-demand changes and incorporation of upgrades. Such a system provides a low cost alternative to specially designed equipment with the added advantage of maximum flexibility. Further, it can be modified to satisfy the specifications (technical and economical) set under different scenarios. In fact, the system described in this paper has already been installed in the HV Lab of the TEI of Crete whereas a variation of it is currently in use in TALOS High Voltage Test Station

Development of an online service for coping with spousal loss by means of human-centered and stakeholder-inclusive design: the case of LEAVES.

To support older mourners after the loss of their partner, LEAVES, an online self-help service that delivers the LIVIA spousal bereavement intervention, was developed. It integrates an embodied conversational agent and an initial risk assessment. Based on an iterative, human-centered, and stakeholder inclusive approach, interviews with older mourners and focus groups with stakeholders were conducted to understand their perspective on grief and on using LEAVES. Subsequently, the resulting technology and service model were evaluated by means of interviews, focus groups, and an online survey. While digital literacy remains a challenge, LEAVES shows promise of being supportive to the targeted end-users

Cohesin SMC1β protects telomeres in meiocytes

Telomeres fail to attach to the nuclear envelope and lose structural integrity in cells lacking SMC1β