Impact of Water Absorptionon Dielectric Properties and Breakdown Voltage of Polymer Epoxy and Xlpe

Polymers have become an alternative option replaces the high voltage insulation materials made of ceramic and glass. The research aims to determine the dielectric characteristics of polymer insulation after water immersion for a certain period of time. The testing was conducted on two types of polymer insulation, namely the epoxy resin and the cross-linked polyethylene cable. The materials were soaked in water with the temperature of 50oC and the measurements were taken every 24 hours for 38 days. The measurements were taken from the mass materials, the relative permittivity and the contact angle. Then, the breakdown voltage measurement and the analysis of the chemical structure of the polymer insulation material were measured when the material had reached saturation state. The research results indicate an increase in the value of the mass and the relative permittivity of the material after the immersion. Such increase level is due to the absorption of the water through the filler in the polymer insulating material. The contact angle value of the epoxy resin material ranged from 56o-80o, which was classified in the category of partially wet. The XLPE material has the value of the average contact angle of above 90o and in the category of hydrophobic. The breakdown voltage value has decreased by 50% in average from the voltage limit before the immersion. The water absorption process has an effect on the decrease of the dielectric strength of the insulating polymer material

Misoprostol alone for the termination of pregnancy

The administration of mifepristone, a powerful antiprogestin, coupled with a prostaglandin, is a highly effective medical method of terminating pregnancy. Of the most widely used prostaglandins, namely gemeprost and misoprostol, the latter shows the greater promise for developing countries, since it can be administered orally and is inexpensive, stable at ambient temperatures and widely available. South African Family Practice Vol. 49 (3) 2007: pp. 1

A combination of imaging techniques for dental medicine: from X-rays radiography and 3D CBCT to OCT

The assessment of dental issues is done nowadays both clinically and radiologically. The latter includes radiographs that are based on X-ray radiation, i.e. intraoral radiography, panoramic radiography, and three-dimensional (3D) cone beam computed tomography (CBCT). In several cases, radiographs have limitations, as they do not reveal dental issues such as small cavities, enamel cracks, or tooth erosion. These aspects can be visible with another medical imaging technique, Optical Coherence Tomography (OCT). The aim of this study is to present a few results obtained with an in-house developed swept-source OCT (SS-OCT) system on several dental issues that cannot be visible on radiographs. These results prove that OCT can be utilized in dentistry, with advantages such as radiation free technique and superior resolution. This study presents both radiography and OCT images for different dental issues which include small cavities, metal crowns cracks, or crowns manufactured with different materials (i.e., zirconia, ceramics, or composite). Firstly, samples have been analyzed radiologically and some abnormalities could be detected, but they could be correctly assessed. Secondly, these abnormalities have been analyzed with the SS-OCT system and finally all images and collected data from both medical imaging techniques have been compared. One of the conclusions is that OCT is more appropriate than radiography for several dental issues such as those presented in this study. These two medical imaging techniques can therefore be complementary in dental medicine

Neuropsychological Functioning in Bilateral versus Unilateral Temporal Lobe Epilepsy

Although relatively specific anatomo-electro-clinical features of temporal lobe epilepsy (TLE) with bilateral ictal involvement (bitemporal epilepsy-BTLE) have been described, differentiating between BTLE and unilateral TLE (UTLE) remains challenging. Surgery is often the treatment of choice for drug-resistant UTLE, whereas its use is more controversial in BTLE. It is currently unclear whether neuropsychological assessment can contribute to the differential diagnosis. We retrospectively reviewed the neuropsychological evaluation of 46 consecutive patients with refractory TLE. Eighteen patients were diagnosed with BTLE on the basis of ictal electro-clinical data, in particular a video EEG recording of at least one seizure simultaneously involving the two temporal lobes without the possibility of lateralizing its onset or at least two different seizures independently arising from the two temporal lobes. Twenty-eight patients were classified as UTLE. Presurgery evaluation data were used in this study. Compared with UTLE, BTLE was associated with a lower intelligence quotient (IQ) and more severe impairment in long-term memory, the latter remaining significant even after controlling for IQ. No significant differences were found between right and left UTLE. In conclusion, BTLE and UTLE are associated with relatively distinct neuropsychological profiles, further supporting their classification as different disorders within the TLE spectrum

Accurate mass measurements of short-lived isotopes with the MISTRAL rf spectrometer

The MISTRAL experiment has measured its first masses at ISOLDE. Installed in May 1997, this radiofrequency transmission spectrometer is to concentrate on nuclides with particularly short half-lives. MISTRAL received its first stable beam in October and first radioactive beam in November 1997. These first tests, with a plasma ion source, resulted in excellent isobaric separation and reasonable transmission. Further testing and development enabled first data taking in July 1998 on neutron-rich Na isotopes having half-lives as short as 31 ms

Features of arrival time and angle-of-incidence distributions of EAS muons

Charakteristika und Abhängigkeiten von Ankunftszeit- und Einfallswinkelverteilungen von Myonen ausgedehnter Luftschauer Verschiedene charakteristische Eigenschaften und Korrelationen von Ankunftszeit- und Einfallswinkelverteilungen von Myonen ausgedehnter Luftschauer (EAS) werden untersucht auf der Grundlage von Monte-Carlo Simulationen der EAS Entwicklung mit Hilfe des Simulations-Codes CORSIKA. Die Ankunftszeitverteilungen und Winkel-verteilungen werden charakterisiert durch die Ankunftszeit bzw. Einfallswinkel des ersten Myons, durch Mittelwerte und Median-Werte der Verteilungen in den einzelnen Schauern. Spezielles Augenmerk wird gerichtet auf Vielfach-Korrelationen bei gleichzeitigen Beobachtungen in verschiedenen Abständen vom Schauer-Zentrum. Es wird gezeigt, daß ein solcher Beobachtungsmode zusätzliche Informationen zur Verbesserung der Unterscheidung der Art der Primärteilchen liefert

Rotational Head Kinematics in Football Impacts: An Injury Risk Function for Concussion

Recent research has suggested a possible link between sports-related concussions and neurodegen-erative processes, highlighting the importance of developing methods to accurately quantify head impact tolerance. The use of kinematic parameters of the head to predict brain injury has been sug-gested because they are indicative of the inertial response of the brain. The objective of this study is to characterize the rotational kinematics of the head associated with concussive impacts using a large head acceleration dataset collected from human subjects. The helmets of 335 football players were instrumented with accelerometer arrays that measured head acceleration following head impacts sustained during play, resulting in data for 300,977 subconcussive and 57 concussive head impacts. The average subconcussive impact had a rotational acceleration of 1230 rad/s2 and a rotational ve-locity of 5.5 rad/s, while the average concussive impact had a rotational acceleration of 5022 rad/s2 and a rotational velocity of 22.3 rad/s. An injury risk curve was developed and a nominal injury value of 6383 rad/s2 associated with 28.3 rad/s represents 50% risk of concussion. These data provide an increased understanding of the biomechanics associated with concussion, and they provide critical insight into injury mechanisms, human tolerance to mechanical stimuli, and injury prevention tech-niques