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Landslides (LS) represent geomorphological processes that can induce changes over time in the physical, hydrogeological, and mechanical properties of the involved materials. For geohazard assessment, the variations of these properties might be detected by a wide range of non-intrusive techniques, which can sometimes be confusing due to their significant variation in accuracy, suitability, coverage area, logistics, timescale, cost, and integration potential; this paper reviews common geophysical methods (GM) categorized as Emitted Seismic and Ambient Noise based and proposes an integrated approach between them for improving landslide studies; this level of integration (among themselves) is an important step ahead of integrating geophysical data with remote sensing data. The aforementioned GMs help to construct a framework based on physical properties that may be linked with site characterization (e.g., a landslide and its subsurface channel geometry, recharge pathways, rock fragments, mass flow rate, etc.) and dynamics (e.g., quantification of the rheology, saturation, fracture process, toe erosion, mass flow rate, deformation marks and spatiotemporally dependent geogenic pore-water pressure feedback through a joint analysis of geophysical time series, displacement and hydrometeorological measurements from the ground, air and space). A review of the use of unmanned aerial vehicles (UAV) based photogrammetry for the investigation of landslides was also conducted to highlight the latest advancement and discuss the synergy between UAV and geophysical in four possible broader areas: (i) survey planning, (ii) LS investigation, (iii) LS dynamics and (iv) presentation of results in GIS environment. Additionally, endogenous source mechanisms lead to the appearance of deformation marks on the surface and provide ground for the integrated use of UAV and geophysical monitoring for landslide early warning systems. Further development in this area requires UAVs to adopt more multispectral and other advanced sensors where their data are integrated with the geophysical one as well as the climatic data to enable Artificial Intelligent based prediction of LS.

This manuscript brings out with an enhancement of the freshwater productivity from the active inclined solar panel basin solar still (AISPBSS). The research was conducted on the AISPBSS by the diversified mass flow rate of water (mf). The maximum freshwater yield obtained at mf at 1.8, 3.2 and 4.7 kg/h is 7.5, 6.5 and 5.4 kg, respectively. The daily average thermal and exergy efficiency of the AISPBSS at mf at 1.8, 3.2 and 4.7 kg/h is 43.71, 38.27 and 29.62% and 8.39, 6.94 and 5.08%, respectively. The daily average PV panel power production of 47.71, 49.84 and 53.83 watts, electrical efficiency of 7.2, 7.6 and 8.1%, thermal efficiency of 17.3, 18.3 and 19.7%, exergy efficiency of 18.32, 20.23 and 22.39%, the overall thermal efficiency of 61.39, 57.44 and 51.37% and the overall exergy efficiency of 26.52, 27.14 and 27.40% are obtained from the system under mf at 1.8, 3.2 and 4.7 kg/h, respectively. When mf increases, there are decreases in the AISPBSS distillate yield, thermal, exergy and the overall thermal efficiency and increases in the PV panel power production and electrical, thermal, exergy and the overall exergy efficiency. Further, energy return term and carbon credit attained for the AISPBSS have been calculated. It was found that payback period of 20, 18.7 and 17.5 years and carbon credit earned of 21, 25 and 30 $ are obtained at mf at 1.8, 3.2 and 4.7 kg/h, respectively.

Regarding the detrimental impacts of using non-renewable energy resources on the environment and the importance of increasing heat transfer in heat exchangers, this research is aimed to increase the heat transfer surface of the collector pipe in contact with the absorber plate at the flat-plate solar collector by designing the pipe in a zigzag shape instead of conventional straight pipe. The 3D coupled investigation of fly ash–Cu/water hybrid nanofluids and analyzing the thermal performance of the proposed solar collector comprising zigzag pipe are the innovation of this research. Also, the effect of variations in mass flow rate, fluid inlet temperature, the volume fraction of nanoparticles on thermal efficiency, Nusselt number, pressure drop, Rayleigh number, and rate of heat transfer coefficient in three irradiations with two types of working fluids have been investigated. Results indicate that due to the enhancement in heat transfer surface in the case where the fluid path is zigzag, the thermal efficiency has improved compared to the straight pipe. In addition, with enhancing mass flow rate, temperature, and irradiation, the average Nusselt number increased. The heat transfer coefficient and pressure drop have the highest value by utilizing 0.5% and 3.5% nanoparticle concentration up to 10.84% and 7.603%, respectively, at a mass flow rate of 0.0089 kg/s, and irradiation of 800 W/m 2 . Finally, by calculating the efficiency index of the proposed flat-plate solar collector, the proper volume concentration for using copper–fly ash/water hybrid nanofluid is obtained at fraction of 0.5% and a mass flow rate of 0.0045 kg/s.

Photovoltaic (PV) technology is considered one of the most effective and promising renewable sources of energy. The PV system’s efficiency strongly depends on its operating temperature, which acts as a defect to the electrical efficiency by increasing over 25 °C. In this work, a comparison was performed between three traditional polycrystalline solar panels simultaneously at the same time and under the same weather conditions. The electrical and thermal performances of the photovoltaic thermal (PVT) system integrated with a serpentine coil configured sheet with a plate thermal absorber setup are evaluated using water and aluminum oxide nanofluid. For higher mass flow rates and nanoparticle concentrations, an improvement in the PV modules short-circuit current ( I sc ) and open-circuit voltage ( V oc ) yield and electrical conversion efficiency is achieved. The enhancement in the PVT electrical conversion efficiency is 15.5%. For 0.05% volume concentration of Al 2 O 3 and flow rate of 0.07 kg/s, an enhancement of 22.83% of the temperature of PVT panels’ surface over the reference panel has been obtained. An uncooled PVT system reached a maximum panel temperature of 75.5 °C at noontime and obtained an average electrical efficiency of 12.156%. Water and nanofluid cooling reduce the panel temperature by 10.0 °C and 20.0 °C at noontime, respectively.

A solar water heater has been developed to convert solar radiation into heat for use in residential and commercial settings. The collector makes up the bulk of a solar water heating system. The solar energy is captured by the collector and transferred to the tube that delivers the working fluid, water. In addition to the collector’s tube, which carries the working fluid, researchers have focused on the design of the collector’s tube. This paper examines the performance of a parabolic plate solar water heater that uses a copper dimpled tube with aluminum-coated tube channels. During the test, the flow rate of base fluid was in the range of 1.0 to 3.0 kg/min in steps of 0.5. The performance of the solar water heater was also evaluated and verified using CFD. The test data such as friction factor, Reynolds number, uncertainty analysis, Nusselt number, solar collector efficiency, coefficient of convective heat transfer, linear dimpled tube velocity analysis, achieving maximum energy efficiency and thermal efficiency have been used to generate parametric values for parabolic plate solar water heaters. The results suggest that the best outcomes can be achieved with a mass flow rate of 2.5 kg/min and the overall thermal efficiency was raised to 31.85%, which is 11% greater than that of the plain tube with base fluid. At mass flow rates of 2.5 kg/min, the pressure drop was found to be 6.24% higher than that of 3.0 kg/min. The experimental results were analyzed and compared with the CFD results, and the overall deviation was ± 3.24% which is in the acceptable range.

In this study, an assessment based on energy, exergy, economic, and environmental approaches on a double-pass (DP) solar air heater (SAH) having pin finned absorber at different air mass ratios up and down the absorber is investigated experimentally. Four air mass ratios are considered: (i) all the air mass flow passes up the absorber and returns to pass down the absorber (DP), (ii) 2/3 of the airflow passes up the absorber and returns to mix with the remainder of air to pass down the absorber (2/3 DP), (iii) the same as (ii) but 1/3 of the air passes up the absorber (1/3 DP), and (iv) all the air mass passes only down the absorber (single pass, SP). For all mass ratios, the performance of pin finned SAH (P_SAH) is compared with that of flat SAH (F_SAH). The results indicated that the air temperature rise and energy and exergy efficiencies of P_SAH are highly greater than those of F_SAH. The highest average thermal efficiency of F_SAH is 56.7% obtained at DP flow condition, whereas the highest value of P_SAH is 65.21% obtained at 2/3 DP with an increase of 17.6% compared with F_SAH. Also, P_SAH has higher average exergy efficiency of about 34.7% compared to F_SAH. Furthermore, P_SAH achieves energy payback time (EPBT) lower than that of F_SAH, while P_SAH has higher embodied energy. The findings indicated that F_SAH at SP airflow pattern has the maximum energy cost (0.0427 $/kWh), whereas P_SAH at 2/3 DP airflow pattern achieves the minimum energy cost (0.037 $/kWh). Finally, the proposed P_SAH system appears to be more viable from exergoeconomic and enviroeconomic approaches compared to F_SAH.

The investment of solar energy in life applications has become mandatory to maintain a clean environment and reduce the use of fossil fuels. This work aimed to improve the performance of solar air heater (SAH) by using evacuated tube solar collectors ETSC integrated with nano-enhancer phase change material (NE-PCM). To achieve this purpose, a system consisting of 5 linked collecting panels was designed, fabricated, and experimentally investigated. Each panel included a glass-evacuated tube with two concentric aluminum pipes installed inside. NE-PCM was placed between the inlet and outlet air paths inside the evacuated tube to enhance the heat transfer rate. The performance was investigated with and without NE-PCM at five mass flow rates (0.006, 0.008, 0.01, 0.03, and 0.05 kg/s). Experimental results revealed that the highest temperature was 116, 108, 102, 95, and 93 °C, respectively, for the above mass flow rates without adding NE-PCM. The outlet temperature was decreased by 6–15 °C when using NE-PCM. The SAH efficiency was increased by 29.62% compared to the system without NE-PCM at 0.05 kg/s. The maximum thermal efficiency for the system with NE-PCM was 62.66% at 0.05 kg/s, and the pressure drop was 6.79 kPa under the same conditions. As well known, the hot air is used for a variety of purposes including space heating, food processing, drying of fruit, vegetables, dairy, and solar cooking.

The objective of the current study is to investigate the performance of the inclined solar panel basin still (ISPBS) incorporated with a spiral tube collector (STC) for various mass flow rates of water ( m f ). The maximum potable water yield of 8.1, 6.9, and 6.1 kg is obtained for different mass flow rates of 1.8, 3.2, and 4.7 kg/h in each instance. Also, for m f of 1.8, 3.2, and 4.7 kg per hour, the daily average energy and exergy efficiency of the ISPBS is recorded to be 47.9, 39.3, and 31.02 % and 9.8, 7.9, and 5.6 %, in each instance. The average electrical, thermal, and exergy efficiency of the PV panel is noted to be 6.5, 7.1, and 7.5 %; 15.67, 17.1, and 18.04 %; and 20.03, 22.21, and 23.36 % for m f of 1.8, 3.2, and 4.7 kg/h in each instance. The rise in m f causes a drop in the fresh water production yield; thermal, exergy, and overall thermal effectiveness; and an enhancement in the power production of the panel, electrical, thermal, exergy, and overall exergy efficiency of the system. Also, the cost of yield production is noted to be low-cost in AISS at minimum m f of 1.8 kg per hour (0.019 $/l) when compared to the other two m f of 3.2 and 4.7 kg per hour (0.022 and 0.025 $/l).

An indirect-type forced convection solar dryer implementing a phase-changing material (PCM) as the energy-storing medium was designed, fabricated, and investigated in this study. The effects of changing the mass flow rate on the valuable energy and thermal efficiencies were studied. The experimental results showed that the instantaneous and daily efficiencies of the indirect solar dryer (ISD) increased with the initial increase in mass flow rate, beyond which the change is not prominent both with and without using the PCM. The system consisted of a solar energy accumulator (solar air collector with a PCM cavity), a drying compartment, and a blower. The charging and discharging characteristics of the thermal energy storage unit were evaluated experimentally. It was found that after using PCM, drying air temperature was higher than ambient air temperature by 9–12 ℃ after sunset for 4 h. Using PCM accelerated the process by which Cymbopogon citratus was effectively dried between 42 and 59 °C of drying air. Energy and exergy analysis of the drying process was performed. The daily energy efficiency of the solar energy accumulator reached 35.8%, while the daily exergy efficiency reached 13.84%. The exergy efficiency of the drying chamber was in the range of 47–97%. A free energy source, a large reduction in drying time, a higher drying capacity, a decrease in mass losses, and improved product quality all contributed to the proposed solar dryer’s high potential.

The current work is about analysis and multi-objective optimization (MOO) of weir-type solar still systems equipped with phase change material (PCM) regarding the exergetic and economic performance. To do so, the energetic and exergetic modeling of the suggested system is conducted then the substantial economic factors is applied to obtain the total cost rate of the considered SSDS. The total exergetic efficiency and total annual cost (TAC) is considered objective functions. Four parameters include mass of the PCM ( m PCM ), inlet brine water flow rate ( m ̇ f ), gap distance ( d ), and insulation width ( x ins ) is chosen as decision variables. Moreover, a genetic algorithm–based MOO was applied to find the optimum states of evaluated solar still unit. The outputs represented that increasing the brine feed water mass flow rate does not affect the TAC while decreasing distilled water production rate. The scattered distribution of optimum states infers that the optimum value of PCM mass is about 1 kg. In addition, applied MOO reveals that with optimization of the studied system, the exergy efficiency increases about 1.47% and the annual distilled water increases 4.35% compared with the non-optimized system. The suggested system is capable to produce fresh water in remote areas without any pollution as well as in a low cost rate.