ABSTRACT

Fiber-optic communication is a method of transmitting information from one place to another by sending pulses of infrared light through an optical fiber. The light is a form of carrier wave that is modulated to carry information. Fiber is preferred over electrical cabling when high bandwidth, long distance, or immunity to electromagnetic interference is required. This type of communication can transmit voice, video, and telemetry through local area networks or across long distances. Many telecommunications companies to transmit telephone signals, Internet communication, and cable television signals use optical fiber. Researchers at Bell Labs have reached a record bandwidth distance product of over 100 petabit × kilometers per second using fiber optic communication. To fulfill the current requirements of Atomic Energy Center, Dhaka considering its smooth operation of high-speed internet service, optical fiber based network is the state-of-the-art network solution. An optical fiber network design refers to the specialized processes leading to a successful installation and operation of a fiber optic network, which includes determining the type of communication system(s), which will be carried over the network, the geographic layout, the transmission equipment required and the fiber network over which it will operate. Atomic Energy Centre, Dhaka (AECD), considered, as the pioneer institution of the Bangladesh Atomic Energy Commission (BAEC) is now one of its research establishments located at the core of Dhaka city was established in 1961 to carry out research and development activities in the field of Nuclear science and technology for peaceful purposes. For that, here internet is essential. Therefore, optical fiber network design and deployment at Atomic Energy center is very important.

Keywords: Optical Fiber, Route Planning, Deployment, Network Design, BTCL, AECD, Frequency band, Wavelength.

ABSTRACT

The low output torque is considered one of the most important disadvantages of the vertical axis wind turbine (VAWT) having the Darrieus airfoil blades, design optimization to overcome this problem, modify the blades of th he Darrieus type by combining it with Icewind blades as the efforts to complement the aerodynamic performance of the turbine. This paper aim is to simulate numerically by using CFD technique with ANSYS 19 software to investigate the aerodynamics performance of the modified model of VAWT by adding three small Icewind blades to the main structure of the three blades Darrieus H-type turbine to increase its overall performance by reducing self-starting ability that associated with increasing the low performance and low rotational speed that associated with the Icewind blades turbine (SST) K-Ω turbulent model is used in this simulation, which is better than the other turbulence models available from a researcher, the finding results from the numerical simulation show that the drag coefficient (Cd), static pressure drop, and starting torque are increased on the positive side and decrease on the negative side of the turbine rotor, the reduction of airflow resistance on the negative side of the turbine blades helps increase the rotation of the turbine rotor, and then turbine output power increases, the results are found to be similar in nature to those reported for VAWT having different blade designs.

Keywords: Darrieus; Icewind, Savonius; Combined Vertical Axis Wind Turbine.

ABSTRACT

In this investigation, polymer matrix composites (PMCs) have been prepared by using unsaturated polyester resin with (sisal and cotton) fiber. These fibers have been added to unsaturated polyester individually and mixed as a hybrid. Molds were produced by hand from silicon rubber by ASTM standards. Different ratios of these fibers were added separately as (3%, 4.5%, 6%, and 7.5% wt.) with (5 mm) length and, the fibers were then blended in (5) mm long (3.75% wt. sisal, 3.75% wt. cotton) to unsaturated polyester and then the tensile strength, Young modulus, elongation percentage at the break, flexural strength, and maximum shear strength tests were carried out. The findings revealed that these properties improve as the weight fraction for both fiber types concentration ratios increases, peaking at (7.5%). While the concentration of these fibers was raised, the elongation percentage at break went down. All composite specimens reinforced with sisal fibers had the lowest elongation percentage at the break and the highest tensile strength, Young modulus, flexural strength, and max. shear strength as compared to composite specimens reinforced with cotton fibers, which were (1.512%, 48.44 MPa, 6.240 GPa, 120 MPa, and 6 MPa) at 7.5% respectively.

Keywords: Natural fiber, Sisal, Cotton, Unsaturated polyester, Polymer matrix composites.

ABSTRACT

Trends focused on the Global Innovation Index (GII) as a measure for progress of nanochemistry. This paper provides projections of recent developments in the word in nanochemistry based on the Global Innovation Index as a predictor for certain Arab countries. The GII is an annual ranking of countries by its ability and performance in innovation and is calculated on a basic average from five and two pillars in two sub-indexes, the Innovation Input Index and the Innovation Output Index. Each pillar represents a trait of creativity and consists of up to five measures, with a weighted average formula for measuring their ranking. In 2008, the GII rose to 36.3 in 2016 from 0.5. The GII is smaller than the GII in Arabic countries worldwide. During the years 2013-2016, the worldwide GII was increasing while for the same period, for Arabic countries, this decline could be explained by economic and industrial wars in the Arab region.

Keywords: Global Innovation Index, Nanochemistry, Development, GII, and Technology patterns.

ABSTRACT

This research aims to investigate the direct effect of the crystallinity on the values of thermal expansion coefficient for selected polymers. The study has included many thermoplastic materials, namely: polyoxymethylene (POM), high-density polyethylene (HDPE), low-density polypropylene (LDPE), polypropylene (PP), polyamide (PA), and polyethylene terephthalate (PET). The degrees of crystallinity ranged from high-values (60-70%), mid-values (30-40%) and low-values (10-20%). The work has been done theoretically and experimentally. Theoretical work has used mathematical functions extracted from reliable empirical relationships. The experimental work has included: manufacturing the specimens; specifying the cooling procedure to get the required degree of crystallinity; measuring the coefficient of thermal expansion for different polymers at various conditions; finally, the data was analyzed and introduced the experiences obtained from the investigation. In general, theoretical values and experimental data were both behave similarly concerning the variation of thermal expansion with the degree of crystallinity. The results show that by increasing the degree of crystallinity, the thermal expansion of the polymer has increased by 30-50%.

Keywords: thermal expansion, crystallinity, polymer, plastic

ABSTRACT

Engineered Cementitious Composites (ECC) containing high volumes of copper slag (HVCS) as a partial replacement of Portland cement (PC) of different replacement levels (0.8, 1.2, 1.6 and 2) by weight of cement, incorporating with graphite (ECC-GR) or with polyvinyl alcohol (ECC-PVA) powders have been studied. Physical properties (bulk density, water absorption and ultrasonic pulse velocity [UPV]), furthermore, mechanical properties (splitting tensile strength and compressive strength), were measured at different curing ages (7, 28 and 90) days. For comparison control mixture was produced, which was free from any mineral additives. The results given, when utilizing of copper slag (CS) as a replacement material of Portland cement in cement mortar with appropriate proportions (0.8) can achieve good sustainable material as well as gain the consistency and mechanical strength of ECC. While, when the replacement ratio was increased up to (2.0), the (ECC) mortar becomes heterogeneous and crumble subsequently that lead to giving poor mechanical and durability properties of mortar. Utilizing of CS as a cement replacement in mortars the appropriate level, leading to decreased PC consumption as well as providing an economic and friendly environmentally advantages.

Keywords: Engineered Cementitious Composites (ECC), high-volumes of copper slag, Graphite, Polyvinyl Alcohol.