Akram Rousan

Effects of absorptance of external surfaces on heating and cooling loads of residential buildings in Jordan

Using the TRNSYS simulation program, the effect of the absorptance of external surfaces of buildings on heating, cooling and total loads has been studied. The meteorological data used in this study are for Amman and Aqaba, representing mild and hot climates, respectively, in Jordan. Two types of construction materials, namely, light weight concrete block and heavy weight concrete were used in the simulation. The effects of the absorptance on energy loads for insulated buildings were also calculated. The results show that, for not insulated buildings, as the absorptance was changed from one to zero, the total energy load decreases by 32%, while for insulated buildings, it decreases by 26% in Amman, whereas this decrease was about 47% for not insulated and 32% for insulated buildings in Aqaba.

POTENTIALS OF ARBITRARY FORCES WITH FRACTIONAL DERIVATIVES

The Laplace transform of fractional integrals and fractional derivatives is used to develop a general formula for determining the potentials of arbitrary forces: conservative and nonconservative in order to introduce dissipative effects (such as friction) into Lagrangian and Hamiltonian mechanics. The results are found to be in exact agreement with Riewes results of special cases. Illustrative examples are given.

Cooling and heating loads in residential buildings in Jordan

Abstract Cooling and heating load calculations for air-conditioned and heated buildings have been calculated for three different cities in Jordan, representing three climatic regions; namely, Irbid, Amman and Aqaba. To analyze the insulation effect of buildings, for each region four combinations of wall and ceiling insulation were considered: no insulation; only wall insulated; only ceiling insulated; and both ceiling and wall insulated. The results showed that the average monthly heating load was reduced when only walls were insulated; however, this has a negative impact on the average monthly cooling load. In the case where only the ceiling was insulated, both the monthly cooling and heating loads were reduced. A comparison showed that with both wall and ceiling insulated, the energy requirements could be reduced by more than 40%. In Aqaba, with both walls and ceiling insulated, there would be no need for any heating during the whole year and in both Amman and Irbid there were at least four months in which there would be no need for either heating or cooling.

The wavelength dependence of Faraday rotation in magnetic fluids

Measurements of Faraday rotation over the wavelength range 450–633 nm in a dilute Fe3O4 particle magnetic fluid are reported. The results, in agreement with the theory, show an enhancement of Faraday rotation near the wavelength λ≊500 nm.

On the concentration dependence of Faraday rotation in magnetic fluids

Faraday rotation and magnetization measurements at room temperature were undertaken on Fe/sub 3/O/sub 4/ particle magnetic fluids with different concentrations. The results show that Faraday rotation follows a Langevin-type behavior with the applied magnetic field. The results also show that Faraday rotation increases with the concentration of the sample and tends to saturate at higher fields for higher concentration. By comparing the optical and magnetic data the role of chain formation in Faraday rotation is discussed. From these measurements, the chain length at given field is found to be linear with the concentration of the sample, a result that is in agreement with recent studies on the concentration dependence of chain formation. >

Faraday rotation and chain formation in magnetic fluids

The Faraday rotation in Fe/sub 3/O/sub 4/ particle magnetic fluids with different concentrations has been measured. The results show that Faraday rotation increases with concentration and tends to saturate at higher fields for higher concentrations. The role of chain formation in Faraday rotation has been investigated by studying samples with the same concentration but with different surfactant contents and by studying the effect of the sample thickness. The results suggest that chain formation has an important role. >

Evolution of a current in a resistor

The current in a simple electric circuit consisting of a resistor and a power supply is studied under the assumption that the current starts from zero and reaches its maximum value. It suggests that an evolution process of a current occurs approximating the circuit temporarily to an R-L circuit. The current equation is solved analytically using Mittag-Leffler function. The equation was also solved numerically. Results supported the assumed behavior of current to evolve from zero to its saturation value.

Solar and thermal energy gain through windows in Jordan

Solar gain and thermal energy transfer through windows is studied for three different sites in Jordan using the TRNSYS computer program. Solar and thermal energy is calculated using the monthly average daily data for the above-mentioned three regions. Calculation of hourly radiation on a vertical plane is presented, and also the method of determination of the amount of radiation transmitted through the glazing layers is given. The effect of window orientation on the total solar gain is analysed. It is found that for all directions, solar gain is season-dependent, and this dependency varies from one direction to another. Calculations are carried out for two cases of glazing location: case 1, glazing flush with the outside of the wall; and case 2, glazing recessed by 15 cm from the outside wall, which represents a window with overhang and sidewalls. The number of glazing layers is taken as 1, 2 and 3 to observe the effect on solar gain as well as on the thermal energy exchange between the inside and outside of the building. During the calculations, the temperature of the inside is fixed at 22°C for the entire year. The results are tabulated to serve as a database for solar and thermal energy in Jordan.

Sensitive detection schemes for small variations in the damping coefficient based on the Duffing-Holmes oscillator with a potential application in magnetic sensing

In this work we proposed two detection schemes based on the non-linear properties of the Duffing-Holmes oscillator for the detection of small variations in the damping coefficient. Theoretically, variations in the damping coefficient up to 0.001% with the possibility to be pushed further can be detected based on our model. A potential on-off magnetic sensor suitable for biomedical applications is suggested by implementing these two schemes with Giant Magnetoresistance based magnetic sensors.In this work we proposed two detection schemes based on the non-linear properties of the Duffing-Holmes oscillator for the detection of small variations in the damping coefficient. Theoretically, variations in the damping coefficient up to 0.001% with the possibility to be pushed further can be detected based on our model. A potential on-off magnetic sensor suitable for biomedical applications is suggested by implementing these two schemes with Giant Magnetoresistance based magnetic sensors.