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Go to Editorial ManagerIn This paper, an experimental study was carried out on a dual channel with perforating “V” corrugated absorber plate of solar air collector which the air flows both in upper channel and lower channel of the absorber plate for increasing heat transfer coefficient and improving thermal performance. The results of experimental procedures for dual channel with perforating “V” corrugated absorber plate of solar collector were compared with the flat plate dual channel of solar collector. Experimental calculations had been performed under Baghdad (33.34° North latitude, 44.4° East longitude) climatic conditions at different values of mass flow rates 0.021 kg/s, 0.027 kg/s and 0.32 kg/s. The results showed that the dual channel with perforating “V” corrugated absorber plate of solar collector is found to perform more efficiently than the flat plate dual channel of solar collector with increased 39% in thermal efficiency. Then, it showed that the efficiency increases with increasing mass flow rates. Also, it showed that the heat removal factor of the dual channel with perforating “V” corrugated absorber plate of solar collector is 36% more than the flat plate dual channel of solar collector. At the last part of the study, the exergy relations were derived for both collectors. The results of this part showed that the flat plate dual channel of solar collector is having largest irreversibility (exergy loss) and the dual channel with perforating “V” corrugated absorber plate of solar collector is having a greatest exergetic efficiency.
The goal is how to estimate video quality of MPEG TCP-Friendly video streaming over robust wireless channel against frequent packet loss. In this paper, a Forward-Error-Correction (FEC) scheme is used as an intra-protection control over an Additive White Gaussian Noise (AWGN) wireless channel behind wired links. For this purpose, we propose Variable Frame Rate based on TCP-Friendly Rate Control (VFR-TCP) algorithm to evaluate the predicted frame rate of MPEG-4 video streaming. Quality of Service (QoS) is also evaluated by the predicted quantizer scale Q for the case that the network throughput is assumed to be equal to the required bandwidth. As a result, we obtained a good and reasonable perceived video quality over a noisy wireless channel, by varying the channel error rate or the channel SNR where AWGN and a coded BPSK scheme are dominated.
The goal is how to estimate video quality of MPEG TCP-Friendly video streaming over robust wireless channel against frequent packet loss. In this paper, a Forward-Error-Correction (FEC) scheme is used as an intra-protection control over an Additive White Gaussian Noise (AWGN) wireless channel behind wired links. For this purpose, we propose Variable Frame Rate based on TCP-Friendly Rate Control (VFR-TCP) algorithm to evaluate the predicted frame rate of MPEG-4 video streaming. Quality of Service (QoS) is also evaluated by the predicted quantizer scale Q for the case that the network throughput is assumed to be equal to the required bandwidth. As a result, we obtained a good and reasonable perceived video quality over a noisy wireless channel, by varying the channel error rate or the channel SNR where AWGN and a coded BPSK scheme are dominated.
The goal is how to estimate video quality of MPEG TCP-Friendly video streaming over robust wireless channel against frequent packet loss. In this paper, a Forward-Error-Correction (FEC) scheme is used as an intra-protection control over an Additive White Gaussian Noise (AWGN) wireless channel behind wired links. For this purpose, we propose Variable Frame Rate based on TCP-Friendly Rate Control (VFR-TCP) algorithm to evaluate the predicted frame rate of MPEG-4 video streaming. Quality of Service (QoS) is also evaluated by the predicted quantizer scale Q for the case that the network throughput is assumed to be equal to the required bandwidth. As a result, we obtained a good and reasonable perceived video quality over a noisy wireless channel, by varying the channel error rate or the channel SNR where AWGN and a coded BPSK scheme are dominated.
The goal is how to estimate video quality of MPEG TCP-Friendly video streaming over robust wireless channel against frequent packet loss. In this paper, a Forward-Error-Correction (FEC) scheme is used as an intra-protection control over an Additive White Gaussian Noise (AWGN) wireless channel behind wired links. For this purpose, we propose Variable Frame Rate based on TCP-Friendly Rate Control (VFR-TCP) algorithm to evaluate the predicted frame rate of MPEG-4 video streaming. Quality of Service (QoS) is also evaluated by the predicted quantizer scale Q for the case that the network throughput is assumed to be equal to the required bandwidth. As a result, we obtained a good and reasonable perceived video quality over a noisy wireless channel, by varying the channel error rate or the channel SNR where AWGN and a coded BPSK scheme are dominated.
An incompressible three dimensional continuity and Navier-Stokes (momentum equations) equations are numerically solved to obtain the pressure drop and fluid friction in laminar steady state micro-channel flow of water. The governing equations are solved by using SIMPLE algorithm with finite volume method and FORTRAN code to obtain pressure field in rectangular micro-channel and then from the pressure field both friction factor f and friction constant Cf are obtained. The results showed that the factors affecting the pressure drop, friction factor f and friction constant Cf are; channel length L, Reynolds number Re, aspect ratio a, channel volume Vch and hydraulic diameter Dh. Increasing of channel length L leads to increase each pressure drop, f and Cf. On other hand, increasing of Re leads to increase pressure drop and decrease the f, while the Cf increase with low value of Re (Re less than 50) and then nearby with approximately constant value. Moreover, increasing of a, Vch and Dh separately leads to decrease pressure drop and increase both f and Cf.
The goal is how to estimate video quality of MPEG TCP-Friendly video streaming over robust wireless channel against frequent packet loss. In this paper, a Forward-Error-Correction (FEC) scheme is used as an intra-protection control over an Additive White Gaussian Noise (AWGN) wireless channel behind wired links. For this purpose, we propose Variable Frame Rate based on TCP-Friendly Rate Control (VFR-TCP) algorithm to evaluate the predicted frame rate of MPEG-4 video streaming. Quality of Service (QoS) is also evaluated by the predicted quantizer scale Q for the case that the network throughput is assumed to be equal to the required bandwidth. As a result, we obtained a good and reasonable perceived video quality over a noisy wireless channel, by varying the channel error rate or the channel SNR where AWGN and a coded BPSK scheme are dominated.
The goal is how to estimate video quality of MPEG TCP-Friendly video streaming over robust wireless channel against frequent packet loss. In this paper, a Forward-Error-Correction (FEC) scheme is used as an intra-protection control over an Additive White Gaussian Noise (AWGN) wireless channel behind wired links. For this purpose, we propose Variable Frame Rate based on TCP-Friendly Rate Control (VFR-TCP) algorithm to evaluate the predicted frame rate of MPEG-4 video streaming. Quality of Service (QoS) is also evaluated by the predicted quantizer scale Q for the case that the network throughput is assumed to be equal to the required bandwidth. As a result, we obtained a good and reasonable perceived video quality over a noisy wireless channel, by varying the channel error rate or the channel SNR where AWGN and a coded BPSK scheme are dominated.
The goal is how to estimate video quality of MPEG TCP-Friendly video streaming over robust wireless channel against frequent packet loss. In this paper, a Forward-Error-Correction (FEC) scheme is used as an intra-protection control over an Additive White Gaussian Noise (AWGN) wireless channel behind wired links. For this purpose, we propose Variable Frame Rate based on TCP-Friendly Rate Control (VFR-TCP) algorithm to evaluate the predicted frame rate of MPEG-4 video streaming. Quality of Service (QoS) is also evaluated by the predicted quantizer scale Q for the case that the network throughput is assumed to be equal to the required bandwidth. As a result, we obtained a good and reasonable perceived video quality over a noisy wireless channel, by varying the channel error rate or the channel SNR where AWGN and a coded BPSK scheme are dominated.
A simulation of fluid-structure interaction (FSI) and combined convective heat exchange is accomplished in an open trapezoidal cavity-channel. A non-Newtonian (power law fluid) is inspected within the laminar region. The heat source is simulated by an isothermal hot cavity bottom wall, whereas all the rest solid walls are perfectly insulated. A deformable baffle is fixed at the top wall of the channel and its free end extends towards the open cavity. The location of the deformable baffle on the top wall is varied. The baffle position is investigated together with Richardson number ($Ri = 0.01-100$) and power law index ($n = 0.5-1.5$). The problem was solved using finite element method with Arbitrary Lagrangian-Eulerian (ALE) technique. The results are compared with the non-baffled channel. The study shows that the proposed baffled channel enhances the heat transfer notably.
The goal is how to estimate video quality of MPEG TCP-Friendly video streaming over robust wireless channel against frequent packet loss. In this paper, a Forward-Error-Correction (FEC) scheme is used as an intra-protection control over an Additive White Gaussian Noise (AWGN) wireless channel behind wired links. For this purpose, we propose Variable Frame Rate based on TCP-Friendly Rate Control (VFR-TCP) algorithm to evaluate the predicted frame rate of MPEG-4 video streaming. Quality of Service (QoS) is also evaluated by the predicted quantizer scale Q for the case that the network throughput is assumed to be equal to the required bandwidth. As a result, we obtained a good and reasonable perceived video quality over a noisy wireless channel, by varying the channel error rate or the channel SNR where AWGN and a coded BPSK scheme are dominated.
The goal is how to estimate video quality of MPEG TCP-Friendly video streaming over robust wireless channel against frequent packet loss. In this paper, a Forward-Error-Correction (FEC) scheme is used as an intra-protection control over an Additive White Gaussian Noise (AWGN) wireless channel behind wired links. For this purpose, we propose Variable Frame Rate based on TCP-Friendly Rate Control (VFR-TCP) algorithm to evaluate the predicted frame rate of MPEG-4 video streaming. Quality of Service (QoS) is also evaluated by the predicted quantizer scale Q for the case that the network throughput is assumed to be equal to the required bandwidth. As a result, we obtained a good and reasonable perceived video quality over a noisy wireless channel, by varying the channel error rate or the channel SNR where AWGN and a coded BPSK scheme are dominated.
The goal is how to estimate video quality of MPEG TCP-Friendly video streaming over robust wireless channel against frequent packet loss. In this paper, a Forward-Error-Correction (FEC) scheme is used as an intra-protection control over an Additive White Gaussian Noise (AWGN) wireless channel behind wired links. For this purpose, we propose Variable Frame Rate based on TCP-Friendly Rate Control (VFR-TCP) algorithm to evaluate the predicted frame rate of MPEG-4 video streaming. Quality of Service (QoS) is also evaluated by the predicted quantizer scale Q for the case that the network throughput is assumed to be equal to the required bandwidth. As a result, we obtained a good and reasonable perceived video quality over a noisy wireless channel, by varying the channel error rate or the channel SNR where AWGN and a coded BPSK scheme are dominated.
The goal is how to estimate video quality of MPEG TCP-Friendly video streaming over robust wireless channel against frequent packet loss. In this paper, a Forward-Error-Correction (FEC) scheme is used as an intra-protection control over an Additive White Gaussian Noise (AWGN) wireless channel behind wired links. For this purpose, we propose Variable Frame Rate based on TCP-Friendly Rate Control (VFR-TCP) algorithm to evaluate the predicted frame rate of MPEG-4 video streaming. Quality of Service (QoS) is also evaluated by the predicted quantizer scale Q for the case that the network throughput is assumed to be equal to the required bandwidth. As a result, we obtained a good and reasonable perceived video quality over a noisy wireless channel, by varying the channel error rate or the channel SNR where AWGN and a coded BPSK scheme are dominated.
The goal is how to estimate video quality of MPEG TCP-Friendly video streaming over robust wireless channel against frequent packet loss. In this paper, a Forward-Error-Correction (FEC) scheme is used as an intra-protection control over an Additive White Gaussian Noise (AWGN) wireless channel behind wired links. For this purpose, we propose Variable Frame Rate based on TCP-Friendly Rate Control (VFR-TCP) algorithm to evaluate the predicted frame rate of MPEG-4 video streaming. Quality of Service (QoS) is also evaluated by the predicted quantizer scale Q for the case that the network throughput is assumed to be equal to the required bandwidth. As a result, we obtained a good and reasonable perceived video quality over a noisy wireless channel, by varying the channel error rate or the channel SNR where AWGN and a coded BPSK scheme are dominated.
The goal is how to estimate video quality of MPEG TCP-Friendly video streaming over robust wireless channel against frequent packet loss. In this paper, a Forward-Error-Correction (FEC) scheme is used as an intra-protection control over an Additive White Gaussian Noise (AWGN) wireless channel behind wired links. For this purpose, we propose Variable Frame Rate based on TCP-Friendly Rate Control (VFR-TCP) algorithm to evaluate the predicted frame rate of MPEG-4 video streaming. Quality of Service (QoS) is also evaluated by the predicted quantizer scale Q for the case that the network throughput is assumed to be equal to the required bandwidth. As a result, we obtained a good and reasonable perceived video quality over a noisy wireless channel, by varying the channel error rate or the channel SNR where AWGN and a coded BPSK scheme are dominated.
A numerical study of mixed convection inside a horizontal channel with an open square cavity that includes an adiabatic rotating cylinder. The bottom wall of the cavity is heated at a constant temperature, and the remaining walls are adiabatic. The flow is incompressible, laminar and steady state. The equations of continuity, momentum and energy are solved numerically using computational fluid dynamics (CFD) with the commercial software package FLUENT 2019 R1. Reynolds number values of 50, 100 and 150, the Richardson number (0.1 ≤ Ri ≤ 10) and the angular velocity ( ω ) of cylinder is (0.5 ≤ ω ≤ 4) rad/sec with direction counter clockwise. Prandtl number for air flow is ( Pr = 0.7). The results are presented in terms of streamlines, isotherms, and the average Nusselt value is given over the heated bottom cavity. The combined effects of natural and forced convection in and out of the cavity were obtained. The results showed that at low Richardson values, Ri = 0.1 the effect of buoyancy force is neglected. The effect of increasing the cylinder speed is clearly noticeable at low Reynolds values, Re = 50. Average Nusselt values increase with increasing rotational speed of the cylinder for all Richardson values.
Hydrodynamics and heat transfer in a fully developed laminar incompressible reciprocating channel flow subjected to a constant heat flux have 'been investigated analytically using similarity transfo1mat ion. An exact analytical solution for the velocity, local, and bulk temperature as well as the Nusselt number has been obtained. The effect of the parameters Pr, Ao, y, and X/Dh on u, T, Tt, Nux, and Nux are presented. The results showed that the local Nusselt number is increased with increasing Womersly number (A.) while the dimensionless temperature is increased with Womersly and decreases with amplitude (Ao). The Prandtl number has a significant effect on the local Nusselt number. The results were found in very good agreement with those obtained numerically using the finite volume method. The comparison with the experimental results of other authors gave a reasonable identification.
A composite beam is an accumulation of different materials so as to form a single unit to exploit the prominent quality of these materials according to their position within the cross-section of the composite beam. The present study investigates the structural behavior of six simply supported composite beams, in which a reinforced concrete T-beam is connected together with a steel channel located at the bottom of a T-beam by means of headed stud shear connectors. The used degrees of shear connection are (100%, 75%, 50%, and 38%). Three dimensional nonlinear finite element analysis has been used to conduct the numerical investigation for the general behavior of beams which are subjected to central point load. ANSYS 12.1 program code was used to estimate the ultimate loads, deflections, stresses, strains, end slip. Concrete was modeled by brick element (SOLID65), while the steel channel was modeled as brick element (SOLID45). Two-node discrete elements (LINK8) are used to represent the steel reinforcement and shear connectors. Perfect bond between the reinforcing rebars and the concrete was assumed. The load on beams was applied monotonically in increments up to failure. The reduction of the degree of shear connection from 100% to 38% causes increasing of strain, mid span deflection and end slip with an average of 3.95%, 13%, and 111% respectively, while the ultimate load decreases with an average of 7.3%. In order to observe the efficiency of the 3-D model, a comparison was made with available experimental work. Good agreement was obtained throughout this work between the finite element and available test results.
In this work, a portable vibration analysis and diagnosis system is designed and constructed. The system is capable of doing most of the known analysis techniques such as FFT, time waveform, cepstrum analysis, dual channel analysis, orbit, envelope detection and other techniques. Furthermore, a new fast and efficient tracking analysis algorithm, suitable for portable instruments, has been proposed. This technique provides the data required to get accurate Bode and Nyquist plots for diagnostic analysis during machine run-up and coast-down tests. Moreover, FFT waterfall and spectrogram techniques have been included. Also, single-plane and dual-plane field balancing have been implemented in this system to execute field balancing tasks.
In this paper the conjugate heat transfer in rectangular channel is numerically investigated, where the effect of both axial heat conduction and entrance region on the internal forced convection in rectangular channels are studied. With decreasing the dimensions of channels the thickness of walls become large and in order of the channels dimensions as in microchannels. As a results the heat conduction in the walls especially in the axial direction can not be ignored, since it lead to decrease in the efficiency of heat transfer process. Also the effect of entrance region is taken into consideration where the flow is assumed developing hydro dynamically and thermally. A finite volume method is used to numerically solve the conjugate heat transfer in both the fluid and wall simultaneously. The results obtained shows that the existing of axial heat conduction lead to reduction in the heat transfer and it's effect increased with increasing the thickness of walls and Reynolds number. In this paper a correlation has been developed to calculate the value of axial heat conduction in channel's walls based on most of the affecting parameters. This correlation can be used accurately to compute the value of axial conduction in rectangular channels.
The investigation of the indoor electromagnetic propagation has been performed at the unlicensed industrial, scientific, and medical (ISM) band, which has gained increased attention recently due to high data rate communication systems developed to operate in it. The effect of the incidence angle and materials thicknesses on the reflection coefficients for both horizontal and vertical polarization has been studied. Two-dimensional ray-tracing model has been suggested to simulate the influence of buildings electromagnetic properties on indoor radio channel characteristics, such as signal level, rms delay spread, and coherence bandwidth. Results show that the influence of the permittivity is more important than the influence of the order of reflection considered for the ray- tracing model. It is also shown that, compared with power level, rms delay spread is more sensitive to the building dielectric parameters. Maximum rms delay spread is dependent mainly on the reflectivity of the walls which dependent on the dielectric parameters.
Mixed convection heat transfer of air in a horizontal channel with an open square cavity is studied numerically. At the center of the cavity, it is an insulated rotating circular cylinder for enhancing the efficiency of heat transmission, the location of the inner cylinder is changed vertically along the centerline of the cavity. Heat is applied to the bottom wall of the cavity at a constant temperature, and the other walls are adiabatic. The flow is steady-state, laminar, and incompressible. Using computational fluid dynamics (CFD) and the commercial software program FLUENT 2019 R1, the equations of continuity, momentum, and energy are numerically solved. The angular velocity of the cylinder range is (0 . 5 ≤ ω ≤ 4) rad/sec in a counterclockwise direction, the Richardson number range ( Ri = 0 . 1 , 1 , 10), Reynolds number is 100 and the cylinder location is ( C = 70 , 50 , 30) mm. The airflow Prandtl number is taken as ( Pr = 0 . 7). The effect of various positions of the rotating cylinder has been examined through the visualization of streamline and isotherm contour, as well as the distribution of the average Nusselt number of the heated surface. The results indicate that the flow field and temperature distributions inside the cavity are strongly dependent on the rotating circular cylinder and the position of the inner cylinder.
This paper is concerned with performance on the widely used control technique: adaptive control for synchronization between two identical chaotic systems embedded in the Master and Slave. It is assumed that the parameters of slave system are unknown. The required stability condition is derived to ensure the stability of error dynamics. Adaptive control laws are designed using appropriate parameters estimation law. The system parameters are asymptotically synchronized; thus the slave parameters can be identified. As an application, the proposed scheme is applied to secure communication system. The information signal is transmitted and recovered on the basis of identification parameters also the system is tested under the consideration of the noisy channel. Finally, through Numerical simulation results, the proposed scheme was success in the communication application.
This numerical study aims to enhance the heat transfer efficiency by dissipating the heat Emitted from electronic processors. A jet impingement technique is utilized with porous layer covering a metal fin as a heat sink. Forced convection and normal convection (due to the buoyancy effect) are taken into consideration. The two equations model (Local Thermal Non-Equilibrium LTNE) employed to describe the energy equations of the two phases of the porous surface. Finite Element Method (FEM) used to discretize these equations to obtain the numerical solution. To make this study closest to the reality, constant heat flux boundary condition is applied underneath the metallic heat sink. The geometry comprises of three domains: Free flow channel, Porous layer and Metal fined heat sink. In order to simulate the heat transfer, isotherms; streamlines and Nusselt number have been considered. Investigation has been done by inspecting the effects of the pertinent non- dimensional parameters such as: Reynolds number ( Re = 100-900), Darcy number ( Da = 10 -1 -10 -6 ), Richardson number ( Ri = 0.1-100) and Porosity ( ε = 0.85-0.95). The results show that increasing Re and decreasing ε lead to enhance Nusselt number. Richardson number below 100 has no significant effects on Nu . At Re above 400, Nusselt number proportional with Darcy number. The enhancement of Nusselt number is found to be 250 % by increasing Re from 100 to 900, 290 % by decreasing ε from 0.95 to 0.85 and about 13 % by increasing Darcy number from 10 -6 to 10 -1 .
This study presents three-dimensional numerical simulations of single-phase laminar flow and forced convection heat transfer of water in a five-layer microchannel heat sink with two channel configurations: radial arrangement and parallel divergence channels. The thermal performance and pressure drop characteristics were evaluated under identical operating conditions, including a constant mass flow rate of 3.925 × 10⁻⁴ kg/s and a uniform heat flux of 90 W/cm². The results indicated that the radial microchannel configuration significantly enhanced both hydrodynamic and thermal performance compared with the parallel divergence design. Specifically, the pressure drop was reduced by approximately 32.5%, the overall performance index increased by about 1.5, and improved temperature uniformity across the heat sink was achieved. These findings demonstrate the superiority of the radial microchannel arrangement for high-heat-flux thermal management applications.
Solar desalination uses solar radiation to convert saline or seawater into clean water and is increasingly crucial due to growing pollution from industrial and automotive sources. Although solar stills offer a sustainable solution, they face challenges in terms of production efficiency. This study presents a new structural design for solar stills, which incorporates advanced insulation materials, a well-designed distillate channel, and an inclined base to enhance productivity. The research explores how different climatic conditions such as wind speed, solar radiation, and atmospheric humidity affect solar still performance. Seven experimental setups were evaluated, comparing traditional inclined stills with advanced closed-loop systems. The results demonstrated that closed-loop systems improved productivity by 28.6% compared to open-loop systems. Additionally, moderate wind speeds increased productivity by 20.82%, while partial cloud cover and light rain decreased productivity by 52.15% and 12.9%, respectively. However, light rain also enhanced condensation efficiency by cooling the glass surface. This study highlights the importance of incorporating environmental factors into the design and optimization of solar still systems for improved performance.