Energy harvesting from pavements has been a topic of extensive research in the recent past. This domain has attracted not only the research community but also the industry and governmental authorities. The various sources exploited for energy harvesting from pavements and roadways are solar radiation, mechanical energy dissipated due to moving vehicles and pedestrians, geothermal energy, rainwater, and wind. This article presents an exhaustive and updated review of all potential means of energy harvesting from these sources. Following the introductory section, the article sequentially covers the energy harvesting methods and their research progress, materials, development of practical systems, commercial status, comparison of technologies, challenges, and concluding remarks. This study reveals that there is wide scope for further research and feasibility studies, which could lead to a wide-spread implementation of the various technologies for energy harvesting from pavements and roads.
In this article cold extrution of carbon electrodes using the direct extrusion die that is designed using one of the theoretical concepts, Constancy of the Ratio of the Successive Generalized Homogeneous Strain-increment (CRHS), is presented. On the basis of the above concept we used three types of dies that are categorized as uniform (UCRHS),accelerated (ACRHS),and decelerated (DCRH) according to the deformation rates. All dies were with fixed reduction area of 50%. The mixture used (filler with binder) was extruded in round section carbon electrodes carried out at 60oC to 80oC. Ten samples are produced and tested for properties such as electrical resistivity, hardness, density and porosity. The results show that the extrusion die UCRHS is the more efficient die design for the production of carbon electrodes.
Though energy-efficient envelope is extensively studied, there is lack of attention on incorporating appropriate passive design strategies at the design-phase of a building in a specific climate and geographic location. This study has focused on the effect of outdoor climate and geographic location on the energy-saving potential of passive shading and thermal insulation for multistory hotel building in the northern hemisphere. The building was modelled and simulated by using DesignBuilder (Version 4.5.0.148). The cities were selected in such a manner that they represent warm, moderately hot, hot, and very hot outdoor climates but different geographic locations (according to Koppen category). The proposed shading strategy was featured by the combination of solar shading devices and self-shading. As an alternative option, the envelope was provided with high-performance insulation and glazing without solar shading. The results indicated that the outdoor climate and geographic location had significant influence on the energy-saving potential of both the options; the factors identified through sensitivity analysis were cooling degree days above the cooling setpoint (CDD-base STC), share of cooling and heating energy demands, global horizontal irradiance, and solar shading effectiveness. For instance, Khamis Mushait and Athens cities have warm outdoor climate, but they represent different geographic locations; therefore, the building's cooling energy demands in these cities were significantly different (98% and 52% respectively of the total energy demand). Accordingly, the energy saving potential of passive solar shading was maximum (65.2%) for Khamis Mushait, while it was minimum (13.1%) for Athens. Conversely, the saving by high-performance insulation ranged from −11.6% in Khamis Mushait to a maximum of only 8.5% in Athens, which is consistent with their heating demands (2% and 48% respectively).
Ventilated discs have gained significant attraction for automobile disc brake due to enhanced thermal performance, but the optimal choice needs careful analysis of thermal and structural behaviors. Following the previous studies on solid and straight ventilated discs, the present study considers discs with three new ventilation patterns namely curved vents, curved vents with holes and curved vents with holes and slots. Three-dimensional modeling was done by SOLIDWORKS 15, and finite element simulation was performed by ANSYS 15. In the thermal analysis, the temperature history during one braking cycle was studied for each model, and the structural parameters analyzed include total deformation, Von Mises stress and contact pressure. The study shows that changing from straight vents to curved vents improves thermal performance without affecting the mechanical behavior. Moreover, the thermo-mechanical behavior is further improved by adding holes and slots on the surface, along with curved vents.
Abstract In the present study, an attempt is made to develop an eco-friendly and compact premixed liquified petroleum gas burner based on surface combustion in a porous inert medium. The premixing mechanism is the combination of a swirler and steel wire mesh packing. The preheating and reaction zones are made up of alumina (Al2O3) foams of pore sizes, 26 and 8 ppcm, respectively. Experiments are conducted with 0.5 liters per minute of liquified petroleum gas fuel, which is found to be the minimum quantity required to produce a sustainable flame when mixed with 4 liters per minute of air, the mixture being highly fuel-rich. The combustion is facilitated by enough secondary (atmospheric) air to ensure complete combustion. The temperature distribution within the combustor; flame stability; maximum flame temperature; NO, CO, and SO2 emissions; and combustion efficiency are measured and compared with those of a conventional domestic liquified petroleum gas stove. The fuel saving potential of the proposed burner is also evaluated. It is found that the proposed burner could yield an 80% savings in fuel consumption and 75% reduction in NOx emissions compared to the conventional one. The CO and SO2 emissions are also well within the global standards.
The rapid advances in technology and improved living standard of the society necessitate abundant use of fossil fuels which poses two major challenges to any nation. One is fast depletion of fossil fuel resources; the other is environmental pollution. The Porous Medium Combustion (PMC) has proved to be one of the feasible options to tackle the aforesaid problems to a remarkable extent. PMC has interesting advantages compared with free flame combustion due to the higher burning rates, the increased power dynamic range, the extension of the lean flammability limits, and the low emissions of pollutants. This chapter gives an outline of PMC, right from the history till the current stage, based on a thorough review of the documented investigations in this area.
Flexible printed circuit boards (FPCBs) are going to replace rigid boards (PCBs) in numerous electronic devices due to their reduced thickness and ability to bend and adapt to various shapes. Deflection and stress are key factors affecting the reliability of FPCBs. In this paper, the fluid flow solver FLUENT and structural solver ABAQUS, are used to study the deflection and stress induced by axial flow fan on FPCBs, in the fan sucking mode. The flow is assumed to be 3-D, laminar, compressible, and steady. The effect of air flow rate on the force acting on the components mounted on the FPCB is analyzed. In the structural simulation using ABAQUS, the deflection and stress are observed for nine cases of different mounting options of the FPCB, at a fixed air flow rate. The proper selections of air flow rate and mounting option are found to be crucial in minimizing the flow induced deflection and stress in FPCBs.
Abstract Superfinishing is one of the methods of high-quality surface machining of elements subjected to high surface wear. It is used for machining external and internal cylindrical surfaces using various models of tools. This experimental study was aimed at determining the effect of machining parameters on surface roughness of high-quality alloy bearing steel. The factors considered were angle of crosshatch pattern (realized by the rotational speed at constant velocity and oscillation), machining time, and pressure of the tool on the machined surface. The experiment was carried out according to the analysis planned for two tools with granulations of 500 and 800. The polynomial and exponential regression equations for subsequent roughness and performance parameters were determined statistically. The multidimensional correlations based on the t-student distribution were established. The results showed that the optimum surface quality depended on the process parameters: grain size, machining time, crosshatch angle, and the contact pressure. The time at which the machining process starts to stabilize with a steady surface roughness was determined to be 120 s. The maximum enhancement of surface roughness was 75% for crosshatch angle of 13°, contact pressure of 0.21 MPa, and granulation of 800. For both 500 and 800 granulations, the diameter loss was in the range of 1–12 microns.
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