Bush encroachment leads to land degradation in semiarid to arid regions. Over 45 million hectares of agricultural land in Namibia are affected. This is worrisome as nearly 70% of the Namibian population depends on agricultural activities and the beef industry is the mainstay of the farming communities. This study employed secondary data sources to provide a review of the problems and benefits o...

In this study; iron based powder metal (PM) bushing compacts were sintered via medium frequency induction heating system. Iron based powders were mixed with 2 wt.% copper (Cu), 0.3 wt.% carbon (C) and 1 wt.% zinc stearat (Zn-st) via V-Type mixer. PM compacts were sintered by 2 different sintering processes. One of them was conventional sintering method other was medium frequency induction sinte...

This paper presents the results of a comprehensive investigation of five blackouts that occurred on 28 August to 8 September 2011 due to bushing failures of the 132/33 kV, 125 MVA transformers at JBB Ali Grid station. The investigation aims to explore the root causes of the bushing failures and come up with recommendations that help in rectifying the problem and avoiding the reoccurrence of sim...

The objective of this study is to design rubber bushing at desired level of stiffness characteristics in order to achieve the ride quality of the vehicle. A differential evolution algorithm based approach is developed to optimize the rubber bushing through integrating a finite element code running in batch mode to compute the objective function values for each generation. Two case studies were ...

Considering the number of failures in high voltage power transformers caused by problems in bushing and winding insulation, it is important to study means for diagnosing incipient failures, to avoid long unavailability periods and its consequences. The aim of this work is to study detection and measurement procedures, concerning the evaluation of position of partial discharge inside the transfo...

A bushing bearing was required between the aluminum connecting rod and the wrist pin to reduce wrist pin bearing wear in a severe application. The bushing could not be machined after assembly and precise control of bearing clearance was achieved by re-sizing (using a mandrel) after assembly. Re-sizing was a critical operation. Too much re-sizing would loosen the bushing pressfit while too littl...

Reliability of power transformers significantly depends on the performance of their bushings and bushing lifetime is mainly dependent on its hottest spot temperature, which is caused by the power dissipation in the bushing’s conductor. In this paper, the thermal analysis of the bushing is firstly performed in twodimensional space using the differential equations. Then, the Finite Element Method...

In order to analyze the cracking and aging reason of the silicone rubber current transformer (CT) insulation bushing used for 8 years from a 500 kV alternating current substation, characteristics including Fourier transform infrared (FTIR) spectroscopy, mechanical properties analysis, hardness, and thermo gravimetric analysis have been carried out. The FTIR results indicated that the external s...

Abstract When the ±800kV UHVDC capacity is increased to 10000MW, transmission current 5kA and 6.25kA, which will put forward new requirements for key technology of through wall bushing: in UHV level, bushing lies research basic voltage sharing field sharing. In case large carrying capacity, heat DC bushing, converter outgoing line device operate at rated voltage, central conductor heated due cu...

Assembled MEMS structures provide a unique design opportunity by overcoming the inherent planarity of MEMS devices, allowing for added flexibility and new application areas. However, external assembly of these devices is frequently problematic. Force and displacement controls are often imprecise at the microscale resulting in damage to the device. In contrast, self-assembling MEMS structures ca...