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 reliabi
lity, 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.
We offer in this research, theory study using a modeling tool for the
possibility of improving the performance of solar pumping system
of rivers using submersible centrifugal pump with variable speed
and moving solar panels controlled by logical microcontroller
programmer (plc.).
In this study، a traditional air source heat pump was modified by adding secondary
evaporator within hot water tank which acted as a water heat source of the heat pump. We
made the heat pump to run alternatively either using surrounding air heat or
water heat
gained from solar power.
We have done experiments during five months starting in December of 2014 until
April 2015. Temperature and pressure were measured at specific points of the cycle. Then
we defined the enthalpy at each point for both cycles using EES software (which is a
software to simulate thermodynamic elements)، and calculated the amounts of heat gained
in the evaporator، heat charged from the condenser، compressor work، coefficient of
performance ، and electrical power consumed by the compressor.
Then we made a compare between the two cycles and found that the improvement
ratio in of the modified cycle to the traditional cycle was 77.07%، and the reduction
ratio in electrical power consumed by the compressor of the modified cycle was 33.54%.
The purpose of this research is to design and realization of an electronic circuitthat is able to control the water level in a tank. The circuit shows a tank water level in decimal numbers and controls the volume of water in the tank. So that when th
e level of water drops below a specific value that is preselected using a probe, the pump water works. When the water level reaches to another limit value, the pump stops working.We used for water level control a container which is made by transparent glass with volume of 15 L. the container is divided in nine levels. In addition to this purpose, because of large applications for realized electronic board, The circuit measures the speed of rotation of DC motorsin a wide range (0001 to 9999) cycles during a chosen period of time that ranges from 1 sec to 110 sec and display the speed of rotation in decimal numbers that appears on four displays. Moreover, the circuit contains a switch reset/start, for display clear and restart of measurement.
This study was carried out on samples of tap water, for several values of distance between the probes, and power supply. We found a quick response in showing levels and high efficiency in performance. We measured the number of special motor cycles for several values of the power supply during 30 s and 60 s, and the relation between the number of cycles and applied voltagewas drawingwe found it a linear relation.
This research presented the experimental study of improving flow
conditions in pump-sump provided with an axial or mixed pump, and
vertical suction pipe, to ensure reducing the minimum needed
submergence of the sump. A physical model of rectangula
r shaped pumpsump
had been studied, with a scale 1\10 , according to Froude Model.
Three modifications had been added, including: floating element, conical
element, and the third one consists of both of them. The flow had been
watched for vortices observation whether surface or subsurface.
Piezometric pressures had been measured at eight points, distributed
equally on the suction pipe perimeter near pump impeller, in addition to
swirl degree measure near pump impeller too. The results showed that the
floating element, set behind the suction pipe, is the most appropriate and
most effective solution to reduce the submergence in pump-sump in way
which the other hydraulic criterions, which control the flow stability
towards the suction pipe in the sump, don't be affected negatively.
The re-use of return air in central conditioning systems is one of the most important
procedures for saving power consumption. However, the requested fresh air of the people
existed within the conditioning space imposes determining the number of ti
mes to be used.
This research aims to link the work of the central conditioning system (heating) of a
facility with the number of people existing within this facility by modifying the ratio of
mixed fresh air and return air to save the electrical power consumption. Also, to raise the
temperature of the mixture air by controlling the flow of hot water continuously rather than
using on-off technique. As well as, to respond to any change in the number of people and
get rid of repeated machine starting.
Our research has been done by using specialized physical model consisted of test
room, heat and movement sensors, pump, water tank, heat exchanger and air mixing
blades. These devices are controlled by microcontroller type PIC16F877A.
The experimentally obtained results showed the ability of controlling the amount of
return air depending on the number of people and controlling the speed of the pump
continuously providing a saving of electrical energy consumption up to 68% compared
with the case of full speed.
We studied the case of 171 patients who had CABG on a beating heart
without CPB.
58 Patients had (EF < 30% ) . All Patients had CABG for LAD, 98 Patients
had CABG for RCA + LAD.
34 Patients had CABG for CX + LAD. only 5 % had post operative
Myoc
ardium infarction. Postoperative Mortality was 0.85% .Other
complications were rare .
