Arduino-based night return mechanism for passive solar trackers

<p>Solar trackers are support platforms that keep photovoltaic panels facing the sun by following the sun from dusk to dawn. There exist active solar trackers that make use of motors and gears to orientate the photovoltaic panels towards the sun; and passive solar trackers that operate through the differential heating of the fluid in the tracking rack to follow the sun. Passive solar trackers suffer from the lack of a night return mechanism and a slow wake-up response in the mornings due to the limitations on the surface inclination angle of the rack. This paper seeks to address these issues by proposing an Arduino-based night return mechanism for passive solar trackers. An energy-saving heating element such as the ultra heating fabric manufactured by WireKinetics Co. is installed on the west-side canister of the tracker. Before dawn, the fabric is automatically heated and this will force the refrigerant in the west-side canister to vaporize and cool in the east- side canister, forcing the tracker to return and face eastward before sunrise. The night return mechanism is designed and simulated using Proteus profesional. Simulation results show that this system can significantly optimize the function of passive solar trackers.</p>

Surface roughness variance on different levels of surface inclination of powder bed fused tool steel 1.2709

Evolution of additive manufacturing has allowed increased flexibility and complexity of designs over conventional manufacturing e.g. formative and subtractive manufacturing. Restricting factor of laser powder bed fusion of metals (PBF-LB/M) additive manufacturing is the as-built surface quality. To promote an understanding of the surface roughness and suitable surface measuring technologies octagon shaped tool steel 1.2709 samples was developed and manufactured. Different surface measuring technologies was also literary reviewed. Studied samples were manufactured with commercially available laser-based powder bed fusion system using standard parameter set provided by the system manufacturer. Surface roughness was measured from top and down skins from multiple different building angles in a way that process specific effects, such as direction of movement of the powder re-coater, was considered. Based on these measuring results of the samples the effect surface inclination are discussed. The results show that building angle strongly affects to surface roughness of laser-based powder bed fused parts. Surface roughness was measured to be more than five times worse in unsupported angle manufactured down facing surfaces when compared with vertical walls.

Experimental Evaluation of Rootstock Clamping Device for Inclined Inserted Grafting of Melons

A grafting machine is a kind of machine that can quickly graft scion to rootstock instead of manual grafting. Currently, an inclined inserted grafting machine uses the mechanical clamping method, which can easily damage the rootstock seedlings due to its high stiffness, thus, reducing the success rate of grafting. This study proposed an effective, flexible clamping device for grafting. The suction hole diameter (HD), the negative pressure (NP), and the surface inclination angle (IA) of the clamping device were studied via a single factor experiment to obtain optimal parameter ranges. Optimal HD, NP, and IA were 2–3 mm, 4–8 kPa, and 10–20°, respectively. The orthogonal experiment results showed that the optimal parameter combination for maximum holding success rate was HD, 2.5 mm; NP, 6 kPa; and IA, 10°. The experimental verification was carried out using the optimal parameter combination, with a holding success rate of 98.3% and no damage. This study provides a reference for the optimal design of an inclined inserted grafting machine.

Self-Loosening Behavior of the Nut Due to Tension Change Considering the Inclination of Bearing Surface

Self-loosening behavior is a topic which many researchers are tackling and the principle is coming clearer. Self-loosening occurs mainly when transverse load is applied to the bolt/nut system and the loosening also occurs when such other loads are applied as impact of the bolt (NAS3350 test type) or temperature difference between bolt and nut. The author reproduced the phenomena by using finite element analyses and found the self-loosening is caused by radial relative displacement between bolt and nut threads. On the other hand, some researchers say the self-loosening occur when the tension changes repeatedly while others say it doesn’t. This axial force phenomenon is not yet clear even in experiment. In this paper, the self-loosening phenomenon by the tension change is examined using Finite Element Analyses. The results show that the self-loosening depends on the inclination of the bearing surface. The loosening does not occur when the inclination of the bearing surface is small enough and it occurs when the inclination is large. As the inclination of the bolt head and nut is allowed within the engineering tolerance and flanges rotate when it fastened making the bolt head or nut bearing surface inclination, the self-loosening may happen for any bolts in nature if tension changes repeatedly.

Hipsimetric and morphometric characters of soil surface in the Gobustan region

It was determined during the research that the relief of the zone is complex, very fragmented and the potential riskiness of erosion is higher. It was defined on the map that a main part of the Gobustan zone, i.e, 68,1% concentrated at an altitude of 500-800 meters. The areas of which surface inclination is more than 10 are 71, 3%. The potential riskiness of the erosion in the zone is very high. It was found that the depth of the local erosion basis is deeper than 50 meters and the most depth is 600-800 meters. It was determined that the south-east end of the Great Caucasus and the Gobustan zones are the most fragmented regions. Here the density of the ravine-gorge network is mainly more than 0,5 km at one kilometre.

Surface Texture Characterization of Metal Selective Laser Melted Part With Varying Surface Inclinations

Additive manufacturing offers the advantage of infinite freedom to design and fabricate complex parts at reduced lead-time. However, the surface quality of additively manufactured parts remains well behind the conventionally processed counterparts. This paper aims to systematically investigate the impact of varying surface inclination angles with respect to the build direction on the resultant surface textures. A bespoke metal truncheon artifact with inclination angles varying from 0 deg to 180 deg was built by selective laser melting. Focus variation microscopy was used to measure the topography of inclined surfaces with a tilt angle of up to 132 deg. The measurement data were then analyzed to characterize the staircase effect and the particles adherent to the artifact surface. Areal surface texture parameters, including height parameters, spatial parameters, functional parameters, and feature parameters, were explored to quantify the general surface topography, the staircase effect, and the particle features. The areal surface texture characterization and particle analysis reveal the resulted surface topographies are strongly correlated with the surface inclination angles.

Radiation Exchange at Greenhouse Tilted Surfaces under All-Sky Conditions

Greenhouses generally exhibit a greater degree of thermal radiation interaction with the surroundings than other buildings. A number of greenhouse thermal environment analyses have handled the thermal radiation exchange in different ways. Thermal radiation exchange at greenhouse surfaces is of great interest for energy balance. It dominates the heat transfer mechanisms especially between the cover material surface and the surrounding atmosphere. At these surfaces, the usual factors of interest are local temperatures and energy fluxes. The greenhouse surfaces are inclined and oriented in various ways and thus can influence the radiation exchange. The scope of this work is determination of the thermal radiation exchange models as well as effects of surface inclination and orientation on the radiation exchange between greenhouse surfaces and sky. Apart from the surface design and the thermal properties of the cover, the key meteorological parameters influencing longwave and shortwave radiation models were considered in detail. For the purpose of evaluating surface inclination and orientation effects, four identical thermal boxes were developed to simulate the roof and wall greenhouse surfaces. The surface temperatures and atmospheric parameters were noted under all-sky conditions (clear-sky and overcast). Differences in terms of surface-to-air temperature differences at the exposed roof and wall surfaces as influenced by surface inclination and orientation are discussed in this work. Overall, the findings of this work form a basis for decisions on greenhouse design improvements and climate control interventions in the horticultural industry.