Evaluation of Silicone Rubber Insulators used in High-Voltage Transmission Lines

Three long-rod silicone rubber composite insulators used in 230 kV power transmission lines were evaluated for aging affects. The insulators were obtained from various outdoor desert locations within Saudi Arabia where they had been in service for 6 years. Surface degradation associated with the aging process was analyzed by using Scanning Electron Microscopy (SEM) coupled with Energy Dispersive X-ray Spectroscopy (EDS), Fourier Transform Infra-Red Spectroscopy (FTIR), and Electron Spectroscopy for Chemical Analysis (ESCA). Electrical performance of insulators was evaluated by Rapid Flashover Voltage Tests (RFVT) and Pollution Severity Measurement Tests. Depending on their locations of service, the samples exhibited various types of pollutants at their surfaces. The analysis indicated that the insulator material showed localized surface degradation while there was no evidence of micro-cracking. Furthermore, it was noted that the electrical performance of the insulators was not significantly affected by exposure during the in-service period

Corrosion of carbon steel caustic header in the presence of chloride ions

Caustic soda produced in caustic cells at a petrochemical plant was loaded into a crude tank by means of a caustic header line made of plain carbon steel. After a fraction of expected service life, the header was severely corroded. Scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) was used to identify the material and the corrosion product. Metallurgical evaluation suggested that the mode of failure was localized attack by chlorine and/or hydrochloric acid at pipe connections (flanges) where concentrated solutions could accumulate. Most evidence pointed out that the failure resulted from corrosion attack due to condensation of hydrochloric acid. Misalignment of the pipe at the flange led to cold work which is also thought to accelerate the corrosion rate. It was recommended to consider a better pipe alignment practice as well as the addition of an inhibitor as a short-term solution. Since the piping system was used close to the critical operating conditions. it was recommended as a long-term solution to replace the caustic header material by one of the higher grades Ni-Cr-Mo alloys

Pain assessment and management in different wards of a tertiary care hospital

OBJECTIVE: To assess the pain management by medical team, emergency room (ER) team and Acute Pain team in a tertiary care hospital. METHODS: The cross-sectional study was done in Medical Ward, Surgical Ward and Emergency Room of Aga Khan University, Karachi, in March-April 2010. The assigned research medical officer visited the three locations every day and selected patients by way of convenient sampling. The study comprised 75 patients; 25 each in three groups. Information was collected on patient\u27s demographics, general characteristics, type of drugs and modalities used. Specific queries about pain were sorted out like adequacy of pain assessment done by primary physician, pain intensity, any intervention done and pain relief post-intervention. SPSS version 17, analysis of variance and Chi square test were used for statistical purpose. RESULTS: The mean current pain score on the visual analogue score (VAS) was lowest in the Surgical Ward which was being managed by the Acute Pain Management Service (APMS) team followed by the Medical Ward and then Emergency Rooms. The difference was found to be statistically significant. The mean of worst pain score was also the lowest in the Surgical Ward. There was significant difference between wards in terms of the use of pain medications. Proper documentation for pain was done for all patients in the Surgical Ward, followed by the Emergency Room and then the Medical Ward. CONCLUSION: Better pain assessment, re-assessment, documentation and patient satisfaction were observed in the Surgical Ward compared to the other two locations of the study

Surface Modification of AI Alloy 2014 by Electrochemical Deposition of Ni

The surface of Aluminum alloy AA 2014 was modified by electrochemical deposition of Ni and its effect on corrosion performance was evaluated. Standard Watt's bath with varying potential, current and time was employed for deposition. The Ni-coated samples were heat treated to improve coating characteristics. Corrosion behavior was studied by electrochemical testing and microstructural characterization was performed using scanning electron microscopy. Microhardness was also undertaken. Experimental results indicate that electrochemical deposition combined with heat treatment can be used to improve the surface properties of Al alloys

Surface Modification of AI Alloy 2014 by Electrochemical Deposition of Ni

The surface of Aluminum alloy AA 2014 was modified by electrochemical deposition of Ni and its effect on corrosion performance was evaluated. Standard Watt's bath with varying potential, current and time was employed for deposition. The Ni-coated samples were heat treated to improve coating characteristics. Corrosion behavior was studied by electrochemical testing and microstructural characterization was performed using scanning electron microscopy. Microhardness was also undertaken. Experimental results indicate that electrochemical deposition combined with heat treatment can be used to improve the surface properties of Al alloys

Rare co-occurrence of dural arteriovenous fistula and arteriovenous malformation with bilateral subcortical and basal ganglia calcification

The present study describes the imaging findings in a patient with dural arteriovenous fistula (AVR) and arteriovenous malformation (AVM) with bilateral subcortical and basal ganglia calcification. A 29 year old male patient presented with chief complaint of recent onset of generalized tonic clonic seizures and mild disorientation. The imaging studies on MCT demonstrated diffuse, symmetric calcification in the bilateral basal ganglia and subcortical white matter. MR imaging and angiography revealed AVM in parietooccipital region with supply predominantly from left posterior cerebral and middle cerebral arteries. Multiple dural feeders from meningeal branches of occipital and superficial temporal branches of bilateral external carotid and right internal carotid arteries. Calcification is proposed to be due to chronic reflux into the parenchymal veins or vascular steal phenomenon. This rare co-occurrence of subcortical calcification in a patient with a dural AVF and AVM is being reported

Size-controlled synthesis of spinel nickel ferrite nanorods by thermal decomposition of a bimetallic Fe/Ni-MOF

In this work, size-controlled synthesis of nickel ferrite nanoparticles was achieved by the calcination of a bimetallic (Fe/Ni) metal-organic framework (MOF). The bimetallic MOF (Fe2Ni-MIL-88B) itself was prepared by a two-step route. The first step involved synthesis of the secondary building unit (SBU) by reacting stoichiometric amounts of Ni and Fe precursors with acetic acid. A ligand substitution reaction (terephthalate replaces acetate) in the SBU leads to the formation of the MOF, which was characterized by PXRD, FTIR, SEM and TEM. Afterwards, the MOF was calcined under air atmosphere to obtain nickel ferrite nanorods. PXRD analysis confirmed the spinel structure of the nickel ferrites while electron microscopic analysis (SEM, TEM) revealed their nanorod-like morphology. By increasing the calcination temperature from 600 to 1000 °C, particle size increased from 16 to 32 nm. Oxidation of benzyl alcohol was used as a model test reaction to probe the applicability of spinel nickel ferrite nanorods for catalysis. Interestingly, the largest nanorods exhibited the highest activity (86% conversion), thus demonstrating the potential of spinel ferrites in catalyzing oxidation reactions

A Machine Learning in Binary and Multiclassification Results on Imbalanced Heart Disease Data Stream

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