Comparison of retinal nerve fiber layer (RNFL) thickness and perimetry findings in glaucomatous patients

Aim: to determine the value of RNFL thickness at which visual field defect becomes detectable. Methods: Our study included 29 normal subject and 36 glaucomatous patient (one eye per person) .Every person was examined by OCTOPUS perimetry with glaucoma 30-2 program, and peripapillary RNFL thickness was measured by HIEDELBERGSPECTRALIS SD_OCT. Results: comparison of results showed higher sensitivity of OCT compared to Perimetry. Mean RNFL thickness at which visual field defect showed was 87 microns. Superior RNFL thickness value which correlated with inferior visual field defect was 101 microns, whereas inferior RNFL thickness value which correlated with superior visual field defect was 75 microns .and the difference in RNFL thickness between normal and glaucomatous visual field was significant (p<0.001). Conclusion: in open-angle glaucoma , it needs significant thinning in RNFL before visual field defects becomes detectable.

Study the effect of pure silica alloy on the curve of the physical dispersion coefficient in optical fiber

The aim of this study is to study the possibilities of obtaining materials with a material shift to the higher wavelengths that fall within the C-Band window currently used in fiber optic communication systems. This is done by mixing pure SiO2 with different materials and different percentages. We find the evidence of refraction of the core material in an optical fiber and study the change of these clues by sequential wavelength of light from the solimer constants obtained from the OptiFiber program. We then calculated the physical dispersion factor DM for each of the studied materials by writing a special matlab program for this study and thus studying the change in the physical dispersion of these materials by the sequential wave length.

Effect of natural pozzolan on the durability of precast products of Glass Fiber Reinforced Concrete (GFRC)

The aim of this study is improving the durability of precast products of Glass Fiber Reinforced Concrete (GRC) and in the context of sustainability applications, reduction of cement consumption and replacement of it with green materials. This study has been done to test the role of the natural pozzolan from Shihan Hill in As Suwayda as supplementary cementing material by 10% -15% -20% - 25%, and to determine the effect of it on the consistency and flexure strength over 180 days, as well as to test its role in improving the micro-structure of the mixture by reducing the content of Ca(OH)2 and increasing C-S-H & C-A-S-H gel, which were tested using X-Ray Diffraction (XRD) and Energy Dispersive X-Ray (EDX) techniques, and as a result reduced the erosion of fibers as shown in images by Scanning Electronic Electron Microscopy (SEM). Moreover the role of pozzolana has been studied in controlling the degradation of the material over time which tested by immersion in hot water 50° for 150 days and by drying – wetting cycles. Also the effect of pozzolana on absorption, porosity and resistance of sulfates attacks was studied. The results have shown that the used natural pozzolana has no negative effect on consistency or mechanical properties, and it improved all the studied durability factors.

Studying and Improvingthe Gain Flattening of a Multi-Pump Raman Amplifier for a 90nm Bandwidth

Modern and future optical networks rely on wavelength divisional multiplexing technology, it was necessary to developed the whole network elements to keep up with the increasing need to offer a wide band and a very short time delay and high reliability, and replacement of electro optic equipment with optical equipment. Optical amplifiers have taken an important part in this evolution, and the Raman amplifier (RAMAN) had a great deal of attention, for its high gain and flattened gain. In this paper, we have examined the effect of both fiber parameters and pump parameters on the performance of Raman optical amplifier in terms of gain and bandwidth and the used pump power. This research demonstrated the effect of multi pump on this amplifier performance and its flattening and bandwidth, and we reached a flattening gain on a wide bandwidth. The simulation was done by using MATLAB and OPTISYSTEM program based on the mathematical equations that describe the amplifier model for 1450nm-1650nm bandwidth.

تحضیر و توصیف مادة لفح حراري شفافة راداریا

Modified resole resin/short silica fiber composite materials have been prepared. The resole resin was synthesized and then blended with Polyvinylbutyral (PVB) polymer with different weight ratios to reduce its brittleness. The mechanical, thermal and physical properties of Resol- PVB blends were studied to characterize these blends and select the most appropriate mixing ratio of polyvinyl butyral with resole resin, which was identified at 15 phr of polyvinyl butyral for every 100 parts of resole resin.

Evaluation of Fracture Resistance of EGlass Fiber Reinforced Composite when Used to Repair two Different Kinds of Dental Ceramic (In-vitro study)

This study aimed to evaluate the fracture resistance of the E glass Fiber Reinforced Composite when used to repair two different kinds of dental porcelain.

TWDM Technology for Next Generation Optical Network NG-PON2

This study examines the most important component of NG-PON2 networks and the characteristics of these network through a model of a system consisting of four pairs of wavelengths to serve 8 subscribers with symmetrical transmission on both tow links equal to 40Gbps, The proposed model designed using OptiSystem program shows good results that give a clear view of the behavior of such systems.

Efficacy Of Strengthening R.C. Beams to resist Shear

Beams are considered as one of the most loaded concrete elements, which needs to be strengthened either as a result of insufficient of concrete section, or insufficient rebar or increased loads, or the result of a superficial steel or corrosion of internal steel reinforcement, and other reasons that we will mention them what we need to study this. The damaged structural elements and their inability to function fully as a result of exposure to different environmental factors damage materials and lead to lower resistance, or because of the existence of of an executive defects or inappropriate investment for its, leads to the need to rehabilitate maintenance and repair or reinforcement. So it was resorting to strengthen either magnify sections or supply necessary reinforcement or steel platelets linking external supported well to concrete section, and because of the difficulty of execution the recent studies has been implemented on the use of more efficient material which is concentrated fiber reinforced polymers. We will present here to methods of strengthening the shear up to the global studies conducted using these materials from polymers, which are characterized by high resistance to tensile and large resistance to environmental factors and weather conditions and ease of application in the specified permissible sites.

Study and analysis of error performance when using multiple pulse position modulation (PPM) over optical fiber

This paper is concerned with an original analysis of an multiple pulse position modulation (MPPM) scheme using graded-index plastic optical fiber.

Study of the shear strength equations of reinforced concrete beams with and without steel fibers and suggestion an equation to the case of lightweight concrete

This paper presents the shear behavior of lightweight concrete beams without shear reinforcement produced by scoria aggregates. A total of nine beams were tested under four-point loads, including three lightweight concrete beams without steel fibers and six steel fiber reinforced lightweight concrete beams.