Suitability of carbon fiber-reinforced polymers as power cable cores: Galvanic corrosion and thermal stability evaluation

The increasing demand for electrical energy and the difficulties involved in installing new transmission lines presents a global challenge. Transmission line cables need to conduct more current, which creates the problem of excessive cable sag and limits the distance between towers. Therefore, it is necessary to develop new cables that have low thermal expansion coefficients, low densities, and high resistance to mechanical stress and corrosion. Continuous fiber-reinforced polymers are now widely used in many industries, including electrical utilities, and provide properties that are superior to those of traditional ACSR (aluminum conductor steel reinforced) cables. Although composite core cables show good performance in terms of corrosion, the contact of carbon fibers with aluminum promotes galvanic corrosion, which compromises mechanical performance. In this work, three different fiber coatings were tested (phenol formaldehyde resin, epoxy-based resin, and epoxy resin with polyester braiding), with measurements of the galvanic current. The use of epoxy resin combined with polyester braiding provided the best inhibition of galvanic corrosion. Investigation of thermal stability revealed that use of phenol formaldehyde resin resulted in a higher glass transition temperature. On the other hand, a post-cure process applied to epoxy-based resin enabled it to achieve glass transition temperatures of up to 200 degrees C. (C) 2014 Elsevier Ltd. All rights reserved.

Bilateral hydronephrosis and hydroureter after ovariohysterectomy using nylon cable tie: a case report

A spayed crossbred female dog was presented due to progressive weight loss, emesis and anorexia over the preceding month. A complete blood count, urinalysis, serum biochemical panel, and ultrasound were initially performed. Computed tomography urography was performed as a complementary exam. Based on ultrasound and CT findings an exploratory celiotomy was performed to remove hyperdense structures that could be the cause of the hydronephrosis and hydroureter in both kidneys. An extensive granulomatous reaction was found near the caudal pole to the left kidney. A nylon cable tie adhering firmly to this tissue was removed during surgical excision. On the dorsal surface of the bladder an extensive granulomatous reaction that had entrapped the right ureter was also noted. Another nylon cable tie was removed and the ureter was released. Eight months postoperatively, the dog was in good general physical condition, showing appetite and vigour. Abdominal ultrasonography showed improvement of the hydronephrosis in both kidneys. The urea ratio was normal, but the creatinine level was slightly elevated, suggesting a guarded prognosis. Thus, bilateral hydronephrosis as observed in the present study should be considered as a major complication after elective ovariohysterectomy.