Dye-sensitized solar cells with PVA–KI–EC–PC gel electrolytes

Gel polymer electrolytes consisting of PVA–EC–PC–KI have been studied in this work. The highest room temperature (298 K) conductivity of 12.92 mS cm −1 is obtained for PVA-based gel polymer electrolyte (GPE) with composition 14.5 PVA-21.7 EC-28.7 PC-30.4 KI-4.7  I 2 (in wt%). The high conductivity is due to the highest number density of mobile ions in the electrolyte. The conductivity–temperature dependence follows the Vogel–Tamman–Fulcher (VTF) relationship. The trend of pseudoactivation energy (Ea) with salt concentration is contrary to that of conductivity. PVA-based GPEs with 5 to 35 wt% KI were used as a medium in ruthenium 535 (N719) dye-sensitized solar cells. The efficiency ( η ) of the solar cells increased as the composition of KI salt in the electrolyte increased. The highest power conversion efficiency of 2.74 % is obtained for solar cells fabricated with electrolyte containing 35 wt% KI. The variation of efficiency follows the same trend as short circuit current density (Jsc) . The increase in Jsc is influenced by the increase in iodide ion concentration in the electrolyte that assists the redox process and helps electron to shuttle between ionized dye and counter electrode

Bound States and Scattering Processes in the ^4He_3 Atomic System

We present a mathematically rigorous method for solving three-atomic bound state and scattering problems. The method is well suited for applications in systems where the inter-atomic interaction is of a hard-core nature. It has been employed to obtain the ground- and excited-state energies for the Helium trimer and to calculate, for the first time, the scattering phase shifts and wave-functions for the He atom-He dimer at ultra-low energies.Comment: 9 pages, main file 21 kB, 1 eps and 4 ps figure

Preparation of Novolac composites with improved properties for disk brake systems

The effect of composition and the dry and wet operating conditions on the adhesive wear resistance of polymeric composite materials were studied in this work. The composite are designed to be used as pads for disc brake system of heavy vehicles. The composites were prepared with weight ratios, Ψ, in the range: 60-90% using the dry method. The composites were reinforced with a number of fillers and friction improvement agents like:  silicon carbide, carbon fibers, alumina, etc at various ratios to establish diverse properties in comparison with Novolac resin. The used ceramic disc brake materials were also utilized in this preparation at certain weight ratios as one of the components of the composites. The wear resistance measurements indicated that a ratio higher than 70% will reduce the hardness of the disc material. Thus, composites with 60% Novolac weight ratio, which indicated the best performance, were prepared with 14-22% of the hardener, the HMTA. The study revealed that the abrasion rate decrease with the reinforcement of the Novolac, i.e., increase in abrasion resistance, especially when the carbon fibers ratio were increased from 1.5 to 3.0%. Meanwhile, the increase of the hardener resulted in increase in the in wear resistance. Further, it appears that the rate of abrasion changes from moderate to in accordance with operating conditions like the applied load, operating time and sliding distance. To mimic the real application conditions, the specimens were subjected to rain water by spraying for 2 min during operation. The wetting caused a lowering of the wear resistance. However, in comparison with the available disc brake materials, our specimens proved either comparable or better performance. Keywords: Novolac composites, wear resistance, brake pads, rain water

Ultracold scattering processes in three-atomic helium systems

We review results on scattering observables for $^4$He--$^4$He$_2$ and $^3$He--$^4$He$_2$ collisions. We also study the effect of varying the coupling constant of the atom-atom interaction on the scattering length

Ethambutol ocular toxicity in a patient with pulmonary tuberculosis a case report

Purpose. To highlight the importance of using the Farnsworth Panel D-15 Hue test in colour vision testing in patients on ethambutol treatment. Case Report. A 70 year-old lady received ethambutol as part of her anti-tuberculous regime. She developed blue-yellow colour defect detectable with the Farnsworth Panel D-15 Hue test, but not with the Isihara Pseudoisochromatic Plates. Ethambutol was immediately discontinued from her anti-tuberculous regime. Two months later, her colour vision returned to normal. Conclusion. This case report illustrates the importance of regular monitoring of patients receiving ethambutol for blue-yellow colour defect using the Farnsworth Panel D-15 Hue Test

The Role of Ultrasonographic Biomicroscopy in the management of a patient with presumed Dematiaceous Mycotic Keratitis - ISPUB

We report the use of Ultrasonographic Biomicroscopy in the management of a patient with presumed dematiaceous mycotic keratitis. AK Tan, PS Premsenthil, A. Aziz, T. Asok, G. Inta

The importance of ophthalmic signs in the diagnosis of suprasellar meningioma - A case report

A forty-two year old lady presented with gradual, painless, progressive blurring of vision of her left eye for four months. There were no other associated ocular or systemic complaints. Examination showed decreased visual acuity in both eyes and a pale optic disc on the left side. Visual field examination revealed a temporal field defect of the right eye which aroused the suspicion of an intracranial mass lesion. MRI of her brain revealed a suprasellar meningioma. We would like to emphasize the importance of visual field examination of both eyes in patients presenting with unilateral loss of vision

Galerkin and Runge–Kutta methods: unified formulation, a posteriori error estimates and nodal superconvergence

Abstract. We unify the formulation and analysis of Galerkin and Runge–Kutta methods for the time discretization of parabolic equations. This, together with the concept of reconstruction of the approximate solutions, allows us to establish a posteriori superconvergence estimates for the error at the nodes for all methods. 1

The ^4He trimer as an Efimov system

We review the results obtained in the last four decades which demonstrate the Efimov nature of the $^4$He three-atomic system.Comment: Review article for a special issue of the Few-Body Systems journal devoted to Efimov physic