Thermodynamic analysis of absorption refrigeration cycles by parabolic trough collectors

"The purpose of this study is to numerically investigate the performance of a solar physical surface absorption cooling system, in which activated carbon/methanol is used as a working pair, which is placed inside a parabolic-shaped solar collector. The governing mathematical model of this issue is based on the equations of conservation of mass, conservation of energy, and thermodynamics of the physical surface absorption process. The equations are discretized using the fully implicit finite difference method, and the Fortran computer program was simulated. A comparison with the results of previous laboratory and numerical studies validated this model. At each point in the bed, the temperature, pressure, and mass of the refrigerant absorbed during the physical surface absorption/discharge process were calculated. In addition, the effects of the bed diameter, amount of solar radiation, source temperature, temperature, and pressure of the evaporator and condenser were investigated on the solar performance coefficient and the specific cooling power of the system. According to the built laboratory model and the working conditions of the system, the solar performance coefficient and the specific cooling capacity of the system are equal to 0.12 and 45.6 W/kg, respectively.

Evaluating Open-Source 5G SA Testbeds: Unveiling Performance Disparities in RAN Scenarios

Fifth generation (5G) standalone (SA) mobile networks are rapidly gaining prominence worldwide, and becoming increasingly prevalent as the telecommunication industry standard. Most published work concerning 5G applications relies on open-source 5G radio access network (RAN) simulation and emulation tools to evaluate various concepts, algorithms, and use cases. However, these tools are not always accurate in conveying a realistic representation of real-world RAN performance and expected quality of service (QoS). This paper discusses the deployment of a 5G SA testbed supporting three different RAN scenarios of real and simulated deployments using open- source software, commercial-off-the-shelf (COTS) hardware, and software defined radios (SDRs). We experimentally evaluate the performance of these scenarios for the RAN and quantify their differences in terms of computational resource utilization, throughput, latency, coverage, and power consumption. Specifically, we explore the emulation and simulation tools' ability to reflect realistic RAN performance and highlight the differences compared to the SDR-based deployment. Through this analysis, this paper provides insights into the performance of each approach and sheds light on the feasibility of using open- source software for 5G testing and experimentation

Modeling and investigating electric power output maximization for piezoelectric energy harvester

In this study, energy harvesting using a two-layer piezoelectric sensor in non-linear single-mode mode was investigated, and the optimal performance conditions for power extraction were investigated. Non-linear equations or non-linear electric enthalpy proposal were obtained using Lagrange’s method. In addition, the model was identified with the help of perturbation methods and based on experimental results. The results indicate the presence of second-order damping and third-order stiffness with magnitudes of 2.8 × 106 and −3.9 × 1021. Finally, non-linear energy harvesting was investigated, and the electrical resistance for an optimal electrical power of 185.2 was obtained