characteristics are not equal to the reverse characteristics (i.e. S12 ≠ S21). So, same antenna can be used for Transmission and Reception of Electromagnetic Waves. Antenna is a passive device, it does not amplify the signals, and it only directs the signal energy in a particular direction in reference with isotropic antenna. Antenna Beam width is the angular width measured at the half power points of the main lobe. Large gain of antenna means narrow beam width. Polarization of EM fields…
high temperature heat addition and low temperature heat rejection at Ericsson cycle. The performance was evaluated in terms of thermal efficiency, exergy losses and specific power output. Energy and exergy analysis was carried out on Braysson cycle and Brayton cycle. The analytical formula was derived for energy efficiency, specific power output, exergy losses of each component, and the exergy efficiency. The influence of various parameters on the performance of the Braysson cycle and Brayton…
Table 2.1: Parameters of tested water turbines (by Shionoet.al, 2002) Solidity (σ) Chord length (C) (mm) Blade inclination angle(ɸ)(°) Height (h) (mm) 0.20 62.8 43.7 300 0.30 94.2 43.7 300 0.40 125.7 43.7 300 0.50 157.1 43.7 300 0.40 125.7 50.0 374 0.40 125.7 60.0 544 Next, the effect of solidity σ on the water turbine characteristics was measured. Figure 2.1 shows a comparative analysis of torque characteristics for different solidity ratios at velocity 1.0 m/s, performed by Shionoet.…
Flexible nature and high surface-to-volume ratio makes monolayer-MoS2 a novel paradigm for tunable gas sensing devices. However, for further improvement in the performance of these devices, a new design strategy is essential to modulate the sensitivity of inert MoS2 basal plane. Here, we demonstrate from first-principles calculations that the gas adsorption properties of monolayer-MoS2 can be modulated through MoS antisite doping and strain. The antisite doped MoS defect with highly localized…
4.4. Physical model of the susceptibility of hot cracking for copper GTA welding Variations of the hot cracking susceptibility during copper GTA welding could be divided into the following five stages combining the internal factor with the external factors, as shown in Fig. 14: Fig. 14. Schematic of the physical model for the susceptibility of hot cracking during copper GTA welding. (I). Free crystalline region The actual line of S-L is lower compared with its corresponding theoretical line…
The term photoluminescence by definition can be refered to as a molecule or atom which absorbs electromagnetic energy and in turn, emits light.In quantum mechanics, it is where excitation to a higher energy state occurs, which then returns to a lower energy state, together with the emission of a photon. According to Seitz (2006) found in the Credo referencing database, “Photoluminescence excitation spectra are determined by measuring emission intensity at a fixed wavelength while varying the…
While there are students who drop out and fail, the majority of students go on to graduate and prove that they have the intellectual potential to succeed. The public seem to think that many students in this millennium do not have the intellectual potential to succeed in college. Many people believe that this generation of students are lazy. This generation is anything but lazy. The students are quite motivated towards their future. The students have the ability to grow and reach new heights.…
The heat exchanger design is an optimization engineering problem, to approach the best solution for sizing and selection of a heat exchanger and also to analyze its thermal performance. A properly sized heat exchanger should incorporate excess capacity to account for fouling that will occur during operation but too much oversizing results in higher manufacturing and installation costs. The most appropriate metric to describe the performance of a heat exchanger is its thermal capacity, which is…
But all sound waves are different too and they are many components that play into this. The energy something makes when it vibrates produces sound waves that have a definite pattern. Each wave can be big or small. Big sound waves have what's called a high amplitude or intensity and we hear them as louder sounds while small waves are the opposite…
surface area for water to escape to the surrounding is decreasing when solute like salt and sugar are added to it. More energy are required to increase the vapor pressure of sugar solution or salt solution to exceed the atmospheric pressure so that…