Zeal Press
Not a member yet
427 research outputs found
Sort by
Inverse Weibull Method Application to wind Speed Modeling in Campo Grande-Ms Brazil
Get PDFWind potential estimation requires an analysis of wind characteristics (wind speed density and wind direction). In this study, the applicability of two distribution models named Weibull and Inverse Weibull aiming to characterize the wind speed distribution in Campo Grande-Ms (Brazil) is investigated. The wind speed data collected from Campo Grande-Ms National Institute of Meteorology (INMET) at 10 m height for 5 years from January 2013 to December 2017, at an hour interval, are used. The method of maximum likelihood estimation is applied to calculate the parameters of the selected distributions. The best distribution function is chosen based on three goodness-of-fit statistics, namely; mean absolute percentage error (MAPE), root mean square error (RMSE), and coefficient of determination (R²). The obtained results indicate that the Weibull distribution provides a more accurate and efficient estimation than Inverse Weibull distribution. Therefore, Weibull distribution can be used to better estimate wind speed distribution in Campo Grande-Ms (Brazil) than Inverse Weibull distribution
Residual Normal and Shear Stresses on Different Machining-Finished Surfaces of Martensitic Ultrahigh Strength Steel
Get PDFMachining induced residual stresses are known to have influenced mechanical properties of high strength metallic alloys. In this paper, we have compared the surface residual stresses of an ultrahigh strength martensitic/bainitic steel grade 56NiCrMoV7 induced by two different machining processes, namely turning and milling. Using the established d~sin2ψ method, x-ray diffraction technique was employed to measure the residual stresses on both the axial and hoop directions of cylindrical samples. The results reveal that, turning finish led to tensile residual stress in the axial direction and compressive residual stress in the hoop direction. On the other hand, milling finish led to compressive residual stresses in both the axial and hoop directions. In addition, large splitting in the d~sin2ψ linear regressions has been interpreted by the presence of residual shear stresses
The Role of Collaborative Service Robots in the Implementation of Industry 4.0
Get PDFThe implementation of the fourth industrial revolution Industry 4.0 is based on the following technologies: internet of tings , cloud computing, big data, robotics & automation, intelligent sensors, 3D printers and radio frequency identification – RFID. The robotics is considered as the core technology. Second-generation industrial robots – collaborative robots have been implemented in the last two years. Their implementation is increasing every year and has reached about 3% of the total application of industrial robots in the world. The development of new technologies has contributed to the development and implementation of collaborative service robots AGV (Automated Guided Vehicle), which is one of the most significant qualitative shifts in the automation of logistic in production processes, assembly lines, warehouses and all other operations where transport is necessary. Their application is motivated by technical and economic reasons, such as: improving the quality of finished products, reducing the production of the finished product, increasing the homogeneity rate - constant quality, reducing the number of workers to carry out tedious transport, increasing the safety of workers in the work process, minimizing production costs and overall maintenance. The paper describes the trend of implementing service robots for professional use, with particular reference to collaborative service robots in logistics. Some design solutions for collaborative service robots in logistics already implemented in the industry are presented
Performance Estimation of Solar Flat Plate Air Heating System Using Helical Tapes
Get PDFSolar flat plate collectors (FPC) are used for heating spaces, water heating, and many other purposes. The present technology of solar flat collectors uses vertical fins. The solar flat plate collector having absorber with vertical fins is provided with a helical tape in the fluid flow path. The absorber plate in the solar flat plate collector has an area of 100 cm x 50 cm. The solar flat plate collector has nine ducts with an area of 27.5 cm x 9.5 cm each. The helical tapes attached have a start angle of 64 deg which pass along the whole length of the duct. The helical tapes have a crosssection area of 1.5 mm x 4 mm. The pitch of the helical tapes is 100 mm. These fins have been attached between the vertical fins of the thickness of 1mm and a height of 10.5 cm. Data such as inlet temperature, outlet temperature efficiency and convective heat transfer coefficient are calculated. The mass flow rate of air is 10.28 kg/s and the air is subjected to solar radiation between 628.98 W/m2 and 708.59 W/m2. The values are noted down, and the and the efficiency is noted to have a 10% rise. The effectiveness of the solar plate collector will increase using a helical fin. A comparative analysis will be done between the conventional flat plate collector and the setup with the helical tapes. The study will show that the helical tapes in flat plate collector will be the best alternative compared to conventional flat plate collector
Numerical Analysis and Optimization of Area Contribution of The PV Cells in the PV/T Flat-Plate Solar Air Heating Collector
Get PDFThis paper presents a practical design of combination solar photovoltaic panel (PV) and an ordinary flat-plate air heating solar collector (FPSC. (The offered collector generated both electrical and thermal power for many applications such as (drying, heating, cooling, etc...). The PV cells are placed in the entrance of the (FPSC), the design avoids the temperature increasing of the PV. In this paper the photovoltaic thermal (PV/T) collector energy analysis were carried out. A mathematical model has been built in order to determine the optimum contribution ratio of the PV cells in the offered collector. The model takes into account the variation of the electrical characteristics with solar radiation and the PV cell\u27s temperature. The obtained results have shown that for a (PV/T) collector of 3m long, the maximum energy extracted from the collector, when the length of the PV panel is 2.4 m and the rest of the collector is ordinary FPSC. Furthermore, the electrical efficiency and the thermal efficiency of the PV/T system was found to be higher than that of the conventional separated systems
Graphene : An Out Standing Material
Get PDFIn photovoltaics, research is aiming to investigate new materials able to push the efficiency limit for solar cells towards the highest values without increasing the fabrication cost.
This paper presents a review about graphene material and its potential use in all technological fields. Due to its high conductivity, transparency and amazing properties. It seems that it has an important place in the next generation of solar cells instead of silicon or thin film based solar cells, researchers found diverse applications for graphene in nanoelectronics, aviation, industry, transport, biomedecine and others.
This paper present a review about the state of art about the graphene material in photovoltaic solar cells where very interesting efficiencies were recorded
Review about Main Requirements for Porphyrin Derivatives as Components of Dye Sensitized Solar Cells
Get PDFThe main aim of this review is to present porphyrins as an entry for developing proper light energy capture materials for photovoltaic cells. A critical opinion about the improving of required properties by changing the molecular structure of porphyrins, including various metallations and substitutions (both in meso and ?-position) as well as by introducing anchoring groups, the importance of sterical hindrance and of the capacity of aggregation, was done in order to understand how these structural modifications affects the photoelectrochemical properties and the efficiencies of dyesensitized solar cells. Using of Zn-porphyrins and of Pt-porphyrins was presented in detail
Effects by Different Microstructure and Texture of Hot Band on the Evolution of Microstructure and Texture after Cold Rolling and Final Annealing of Ferritic FeSi Steels
Get PDFIt is well established that there is an interplay and interaction between the processing steps at fabrication of non-oriented electrical steels: hot rolling, cold rolling and annealing with respect to the evolution of the microstructure and texture. In this paper we will analyse in detail by optical microscopy and EBSD-measurements the influence of the microstructure of hot band prepared in different ways on the deformation structure after cold rolling and finally the evolution of microstructure as well as texture at final annealing due to recrystallization followed by grain growth. It will be demonstrated that the microstructure of the hot band effects the start of the recrystallization and finally the start of the grain growth at final annealing. The evolution of the microstructure at the stage of recrystallization is rather inhomogeneous across the thickness. This results from the complex deformation substructures after cold rolling. It will be pointed out that an explanation of the texture evolution at recrystallization only by in-plane compression stress fails. The inclusion of shear stress may explain the observed figure for the texture. The grain growth, which is necessary for the non-oriented electrical steels to reach the desired low values of specific magnetic losses, is finally the dominant process at the relevant higher annealing temperatures. The evolution of texture at recrystallization is different from those at grain growth
Stress Field Analysis of Polymer Composite with Orthogonally Reinforced Fibers
Get PDFThe photoelastic technique was used to analyze the stress field in glass fiber reinforced polymer matrix composite. Two glass fiber bundles with a diameter of 0.2 mm were reinforced in orthogonal directions. The composite was subjected to diametrical compression with two orientation of fibers with respect to the loading axis, i.e. 00/900 and 450/1350. A circular polariscope with dark-field arrangement was used to analyze the stress field. The isochromatic fringe pattern nearby fiber/matrix interface revealed that there was strong adhesion between the fiber and matrix. Distorted fringes were observed nearby fiber region which indicated efficient load transfer from matrix to the fiber. It was observed that composite with 450/1350 orientation of fibers showed more principal stress difference in the direction perpendicular to the loading axis
Modeling and Control of Underactuated Three-Dimensional Overhead Crane Systems
Get PDFOverhead crane systems play a vital role in different factories to transport heavy loads. This paper provides an overview of recent developments in the modeling and control of three-dimensional overhead crane systems. It provides a categorized survey of the published work. Different control methodologies when applied to overhead crane are examined, outlined and assessed to aid for future work