Structure, Dielectric Properties and AC Behavior of Commercial Polytetrafluroethylene (PTFE) Polymer

In this work the relative permittivity (ε''), dielectric loss (ε'') and AC-conductivity for commercial polytetrafluroethylene (PTFE) have been measured at different temperatures (20-110°С) and over the frequency range from 10 KHz to 1 MHz. The infrared (IR) spectra of PTFE also been investigated to detect the presence of polar groups and carbon double bonds. The relative permittivity had observed to decrease with increasing frequency and temperature. Some loss peaks were observed in the dielectric loss spectra, which referred to the relaxation, arises from the orientation of unsaturated double (C=C) bond and polar additives. The diameter of the semicircles in Cole-Cole (ε' versus ε'') plots are not coincides with x-axis at different temperature which reveals that the relaxation processes are non-Debye type. The AC-conductivity increases with increasing of frequency and almost independent on the temperature

Behavior of hybrid high-strength fiber reinforced concrete slab-column connections under the effect of high temperature

AbstractConcrete can be modified to perform in a more ductile form by the addition of randomly distributed discrete fibers in the concrete matrix. The combined effect of the addition of two types of fibers (steel fiber and polypropylene fiber with different percentages) to concrete matrix, which is called hybrid effect is currently under investigation worldwide. The current research work presents the conducted experimental program to observe the behavior of hybrid high strength reinforced concrete slab-column connections under the effect of high temperature. For this purpose, ten slab-column connections were casted and tested. The experimental program was designed to investigate the effect of different variables such as concrete mixture, column location and temperature fighting system. All specimens were exposed to a temperature of 500°C for duration of two hours. To observe the effect of each variable, specimens were divided into four groups according to the studied parameters. The test results revealed that using hybrid high strength concrete HFHSC produced more strength in punching failure compared with high strength concrete HSC when exposed to elevated temperature. Fighting by air had higher initial crack load compared with that for without fighting and fighting by water. On the other hand, fighting by water decreased the ultimate load

Comparison of keorolac with morphine for intraoperative analgesia in patients undergoing total abdominal hysterectomy

Direct laryngoscopy and endotracheal intubation during anaesthesia and cutting, stretching and tissue manipulation during surgery is the most painful time for a patient undergoing surgery. The elicited pain during a surgical procedure is associated with significant hemodynamic changes including rise in blood pressure, heart rate, sweating, pupillary dilatation etc. These hemodynamic changes are not desirable and may produce deleterious effects in patients with hypertension, ischemic heart disease and cerebro-vascular disease and impose a great challenge for anaesthesiologist to maintain physiologic homeostasis during these periods of stress. Opioids are considered to be the corner stone in the management of intraoperative and postoperative pain, morphine being the gold standard . Use of Opioids to provide intraoperative analgesia is associated with some untoward effects i.e., somnolence, respiratory depression and nausea and vomiting, which are well known causes of delay in discharge from the post anaesthesia care unit (PACU) and unplanned hospital admission or delay in discharge to home-1

Ethical issues in e-learning.

E-Iearning is becoming a fast growing sector of higher education. Although there are many advantages of e-Iearning, yet there are some ethical issues related to e-Iearning. This paper provides a general overview of such ethical issues. It also provides some strategies to overcome them

Crystallization of osumilite from modified basaltic glasses

Osumilite-type phases, which have high temperature stability and low linear thermal expansion coefficients, were crystallized from modified basalt glass composition. To satisfy the compositional requirements of osumilite molecules, a deliberate amount of kaolin, sand, magnesite and TiO2 should be added to the basalt. The crystallization process was investigated by DTA, X-ray diffractometry and SEM. The effect of compositional changes on bulk crystallization and growth morphology was also studied. The linear thermal expansion coefficient was measured to characterize the produced glass-ceramics

Extracorporeal Shockwave Therapy for Painful Chronic Traumatic Heterotopic Ossification after Right Acetabulum Fracture Fixation: A Case Report and Literature Review

BACKGROUND: Heterotopic ossification (HO) usually occurs in trauma, such as fractures. To the best of our knowledge, there is a lack of studies about the effects of shockwave on the size of HO in the literature. AIM: The aim of this study was to describe the effects of extracorporeal shockwave therapy (ESWT) on the size of HO as well as the lower extremity functions in patients with fracture right acetabulum. CASE REPORT: A 36-year-old gentleman had a traffic accident on August 30, 2015, resulted in a fracture of the right acetabulum treated by open reduction and internal fixation on September 2, 2015. The patient has complained of severe right hip pain with limitation of daily activities, especially walking, standing, and sitting, visual analog scale about 7-8/10 with painful and restricted ROM of the right hip. Plain X-ray of the right hip revealed HO at greater trochanter with a long axis length 37.3 mm. ESWT was applied for HO. ESWT was administered 6 times each weekly for 6 weeks. At 6-month follow-up, the size of HO had become slightly smaller with the improvement of pain, and lower extremities functions. DISCUSSION: Soft tissues around HO have been regenerated from ischemia for several reasons such as ESWT stimulating angiogenesis and neurogenesis and the size of HO had become slightly smaller by radial shockwave therapy. CONCLUSION: ESWT is a novel non-invasive and safe treatment for HO. The effects of ESWT on the size of HO had become slightly smaller with the improvement of lower extremities functions