EVOLUTION OF CROWD-SOURCING FROM COMPUTER TO MOBILE SYSTEMS

As crowd-sourcing is becoming popular for problem solving and completing a task, it is now very important to use this concept in an advance manner. It can also be used as a distributed and vast source of information. This concept is now evolving in world of mobile systems. This will be a little different from that of computer systems. In this paper, we have discussed some new technologies and challenges before us to implement these advancements in crowd-sourcing. We are going to talk about cheat-detection techniques, handling multimedia databases and how to trade off between cost and accuracy by considering the redundant data as well

Solar energy: direct and indirect methods to harvest usable energy

The global energy demand is increasing substantially due to increasing population, industries, and technological development. The renewable energy sources can play vital role to cope up with the rising demand for energy and reduce greenhouse gas emissions. Solar radiation is a source of renewable energy from sun, and it can generate electrical and heat energies using appropriate harvesting techniques [1]. The solar energy can be employed in two forms, which are solar thermal and photovoltaics. The solar energy can be directly converted into electricity (by solar photovoltaics) or indirectly converted into heat energy (by solar thermal collectors). Although photovoltaic (PV) requires high capital cost, this technology is accepted worldwide due to less maintenance and operating cost

Integration of emerging PCMs and nano-enhanced PCMs with different solar water heating systems for sustainable energy future: A systematic review

Solar water heaters (SWHs) are primarily used to generate hot water to meet daily needs in domestic and industrial applications. Due to its technical and economic practicality, solar water heating has been widely exploited for use of solar energy. However, the inconsistent availability of solar radiation and lack of energy storage facilities restrict its utilization. Thermal energy storage materials (Phase change materials and nano-enhanced phase change materials) are key solutions for effectively harvesting thermal energy from solar radiation. Integrating phase-change materials (PCMs) and nano-enhanced phase-change materials (NE-PCMs) with SWHs overcome the constraint of only being used during the daytime and making them more efficient. The main aim of this systematic review article is to summarize and highlights the key results of recent studies on SWHs integrated with PCMs and NE-PCMs for domestic and industrial water heating applications. This study also highlights the technical issues associated with SWH systems. In addition, the perspectives, recommendations, and future improvements of the SWH systems integrated with PCMs and NE-PCMs are explored to overcome the technical barriers to their practical use. In conclusion, the thermal performance of SWHs with the help of PCMs and NE-PCMs increased significantly, and the cost of the system was reduced, resulting in a shorter payback period compared to conventional SWHs. Also, there is a considerable reduction in CO2 emissions from an environmental perspective. It is intended that this study will provide new insights to the researchers to design and develop highly efficient SWH systems

Effects of printing parameters on the mechanical characteristics and mathematical modeling of FDM-printed PETG

3D printing technology has revolutionized free-form construction and customization demand through its ease of use, fast production, accurate, regulated deposition, and flexibility with soft functional materials. Fused deposition modeling (FDM) is an ideal technique for the 3D printing of plastics. The low cost, high prototyping precision, and ease of use make it a popular additive manufacturing process. The dimensional stability, quality, functionality, and properties of printed specimens are all affected by the process parameters used in the FDM technology. As such, the present work investigates the effect of the infill pattern and infill density on the PETG mechanical characteristics. The work also finds the optimum parameters to enhance the mechanical properties using the response surface methodology (RSM). Scanning electron microscopy (SEM) was used to study micro-surface defects under different processing conditions. Based on the tensile strength experiments, the concentric pattern was recorded to have the highest UTS, E, and yield values compared to the other designs, at 28.53 MPa, 0.81 GPa, and 20.00 MPa, respectively. In contrast, from compression analysis, the highest compression strength and compression modulus (24.03 MPa and 3.71 GPa, respectively) were obtained for the triangular infill pattern, which absorbs more compressive force compared with the other patterns. Meanwhile, it was also observed that increasing the density from 25 to 75% improves mechanical properties. The RSM analysis reveals the significant parameters for both testing methodologies with mathematical models to predict the properties with 95% certainty

PCM-assisted energy storage systems for solar-thermal applications: Review of the associated problems and their mitigation strategies

Latent heat energy storage (LHES) system is identified as one of the major research areas in recent years to be used in various solar-thermal applications. However, there are various challenges associated i.e., low thermal conductivity, leakage issues, stabilization concerns, etc. In this work, a comprehensive review of studies dealing with these problems and their mitigation strategies. Various design parameters influencing the performance of PCM-assisted systems are also discussed. This article further presents a detailed review of several mathematical models, based on system enthalpy and heat capacity-based modeling schemes along with the techno-economic analysis. The review results reflect the application of porous foams increasing thermal conductivity values of PCM composites relative to pure PCM working mediums. Moreover, the use of extended surfaces with appropriate geometries reduces the phase transition durations for the working medium significantly which enhances the thermal performance. Additionally, PCM encapsulations are identified as one of the widely accepted procedures intensifying the thermal performance of energy storage systems. However, the selection of appropriate encapsulation shell material and shell geometries are some of the important factors to be considered to ensure optimum system performance. This review focuses on the significant aspects of PCM encapsulation design parameters for several solar-thermal systems

Optical absorptivity and thermal conductivity analysis of silver nanoparticle dispersed salt hydrate PCM

Thermal energy storage using phase change materials (PCM) s are of notable technique towards improving the utilization of solar energy mix within the global energy consumption. Major problem with solar power is its intermittent nature. Phase change materials acts as a thermal battery to store thermal energy received from the sun, and use the same during absence of sun. In spite of numerous advantages PCM suffers due to low thermal conductivity and specifically organic PCMs are flammable in nature. In this particular research investigation, we choose inorganic salt hydrate PCM and disperse silver nanoparticle to enhance their thermal characteristics. Sodium phosphate dibasic dodecahydrate (SPDD) is the opted inorganic salt hydrate PCM. Silver nanoparticle dispersed SPDD PCM are prepared at different composition of SPDD-0.3Ag%, SPDD-0.5Ag% and SPDD-0.7 Ag% using a two-step water bath sonication process. The prepared samples are explored experimentally using FTIR spectroscopy and UV-VIS Spectroscopy to evaluate their chemical and optical absorptivity behavior. Thermal conductivity of the composite inorganic salt hydrate PCM are determined using numerical model available in the literature. Results ensure better optical absorptivity and thermal conductivity for the composite salt hydrate sample with higher concentration of silver nanoparticle. Prepared composite PCM are expected to enhance the thermal energy storage with significance to contribute towards sustainable development goal of clean and affordable energy

Multi-wall carbon nanotubes tailored eutectic composites for solar energy harvesting

Carbonaceous thermal energy storage involving PCMs has gained an increasing research interest owing to their higher thermal conductivity and energy storage density. The current work analyses the thermophysical properties of a nano-enhanced eutectic phase change material (NeUPCM) laden with different concentrations (ranges from 0 wt% - 0.7 wt%) of multi-wall carbon nanotube (MWCNT). Paraffin wax-palmitic acid (PW-PA) binary eutectic was produced initially by facile melt blending, and then MWCNTs were doped via standard two-step nanocomposite synthesis protocol. Nanocomposites showed a slower decomposition rate, and the thermal resistance index improved. MWCNT enhance the thermal conductivity of the eutectic base (140 %), which reaches a maximum value of 0.619 W/(m•K) for 0.5 wt% loadings, and the maximum increment of 13.2 % of latent heat was noted for 0.7 wt% loading of MWCNT (which is having a melting temperature of 53 °C). The sample doped with 0.5 wt% MWCNT(C3) showed the highest thermal effusivity. The NeUPCMs also displayed improved photothermal performance and solar absorptivity. Corrosion analysis against copper revealed that the composite is suitable for long-term usage. The NeUPCMs maintained good reliability even after 500 melt-freeze cycles. In short, the proposed NeUPCMs hold significant potential to be employed for thermal energy storage purposes

Copper oxide/polyaniline nanocomposites-blended in palm oil hybrid nanofluid : Thermophysical behavior evaluation

In the present work, Copper Oxide-Polyaniline (CuO/PANI) nanocomposites-blended in palm oil hybrid nanofluid have been prepared via a two-step method and investigated as potential heat transfer hybrid nanofluids for the first time. Initially, CuO/PANI nanocomposites are synthesized via oxidative polymerization by varying the weight percentage of CuO nanoparticles (1, 5, and 10 wt%) and characterized using TEM, EDX, XRD, FTIR, and TGA analysis. The findings revealed a successful fusion of nanocomposite composed of spherical CuO nanoparticles embedded in flake-like PANI. The formulated CuO/PANI-palm oil hybrid nanofluids are prepared at a volume concentration between 0.01% and 0.5% and stabilized using an ultrasonication process without any surfactant. UV–vis and sedimentation observation revealed that all nanofluids remain stable for up to a month. FTIR analysis reveals that all formulated nanofluids are chemically stable as no formation of new peaks obtained with the dispersion of nano additives. The TGA analysis affirmed better thermal stability in all nanofluids compared to base fluids. Density evaluation of formulated nanofluids shows a linear relationship between density and volume concentration of nanocomposites but decreased with temperature. Rheology study indicates that palm oil exhibits viscous flow behavior similar to Newtonian behavior. Nanofluid containing 10 wt% CuO/PANI nanocomposites displayed having the highest viscosity and thermal conductivity properties (31.34% enhancement) compared to the rest prepared nanofluids. Mathematical equations were developed at the final stage of the research for future properties prediction

Optimization of impact energy of copper-polylactic acid (Cu-PLA) composite using response surface methodology for FDM 3D printing

This study attempts to provide a statistical evaluation of the effect of Cu wt.% and infill pattern on the FDM-based 3D printed parts' impact properties. The developed model is based on the acquired experimental data accompanied by response surface methodology (RSM) analysis. The confidence level for RSM is set to 95% (? = 0.05), where P-value lower than 0.05 shows a significant effect by the parameter. Besides determining significant parameters, this analysis also provides modeling of impact properties and optimizes the desired mechanical performance parameter. ANOVA analysis includes data of standard deviation (S), coefficient of determination (R2), adjusted and predicted (R2). Infill pattern and Cu wt.% show a significant effect on both factors, including energy absorbed and impact strength. The model created for the energy absorbed and impact strength has an error of 7.23 % and 6.60 %. The maximum energy absorbed and impact strength obtained through optimization is 2.5180 J and 35.3657 kJ/m2, respectively, through the combination of two main factors, including Concentric infill pattern with 25 wt.% Cu. The mathematical models of the impact properties were also developed using RSM, focusing on varying copper composition and infill patterns, which can be used to predict desired impact properties

Bismuth as efficient sintering aid for TiO2-based low temperature dye sensitized solar cell

Flexible dye sensitized solar cell (DSSC) developed at low temperature with low conversion efficiency due to the poor interparticle contact and charge transfer has limited their further development. In this research, bismuth (Bi) nanoparticles were implemented as titanium dioxide (TiO2) photoanode sintering aid to combat this issue. By utilising the liquid phase sintering theory, interparticle contact of photoanode was improved due to neck formation at the TiO2–Bi matrix. This feat was achieved even at low temperature (150 °C and 200 °C) because Bi have a low melting point of 271.5 °C. The charge transfer was also found to have increased while the resistance lowered with the implementation of Bi from the plasmonic effects of Bi nanoparticles. The highest conversion efficiency was obtained at 7.93 % for the TiO2-5wt% Bi sample sintered at 200 °C. The efficiency was 2%–16 % higher than controlled DSSC samples prepared at high temperature (450 °C). The improvement in interparticle contact due to neck formation and enhanced charge transfer with reduced recombination reactions was attributed as the reason for the superior performance. Increasing the Bi composition even further caused reduction in the efficiency due to layer cracking and electron trapping sites from high amount of Bi