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Versatile Personal Assistant Dedicated to B/VIP
Get PDFToday, there are different systems on the market that aim to help Blind or Visually Impaired People (B/VIP) to gain more independency and self-trust. From the classic white cane to various intelligent devices to guide people with vision problems, most of the systems are expensive, difficult to be used or with low efficiency. The subject is a very important one because, according to the World Health Organization, there are approximately 2.2 billion people in the world that have a vision impairment or blindness. Thus, the purpose of this work is to make a short survey on solutions available on the market, in order to develop a low-cost, efficient and easy-to-use system for both indoor and outdoor use. The versatile personal assistant dedicated to B/VIP aims to enhance their independence and also improved outdoor navigation. The smart warning system addressed here is an innovative device aiming to detect obstacles with the help of ultrasonic sensors and warning of their presence by means of a buzzer or vibration. The system, when used outdoor, also gives the possibility to send short message to the B/VIP’s own assistant, in the form of an SMS with the exact location of the B/VIP. Moreover, the SMS’ content can easily create the optimal route to the B/VIP’s location with the Google Maps support for a fast-time assistance
A New Magnetorheological Composite Gel and Its Controllable Rheological Behaviour
Get PDFA series of magnetorheological composite gels (MRCG) were prepared using carbonyl iron powder as the magnetic particles, a complex of methyl silicone oil and gelatin/agaropectin colloids as the matrix and various additives. The rheological behaviour of the samples was tested using a rheometer in rotary and oscillatory shear modes. The results demonstrate that rheological behaviour is significantly dependent on the colloid content of the matrix. The shear yield strength increases with increasing colloid content of the matrix and reaches a maximum of 92.1 kPa. The linear viscoelastic range of the MRCG is almost independent of colloid content. In addition, the shear storage modulus of the MRCG increases with increasing colloid content, and the maximum value of the change in absolute modulus is 2.526 MPa. Adding nanosized SiO2 can significantly improve the shear yield stress and broaden the controllable range of the MRCG under a magnetic field
Fabrication and Evaluation of Two-Junction Carbon Thin Film Photovoltaic Devices
Get PDFIn this work, we have fabricated the two-junction carbon photovoltaic devices which consisted of Al/fullerene (C60)/amorphous carbon (a-C)/C60/a-C/ITO glass structure. We also investigated their photovoltaic properties with the same bandgap and without involving the tunnel-connect layer. We found that the open-circuit voltage in the two-junction photovoltaic device almost doubled compared to the single-junction type and it confirmed that the tandem structure was successfully formed without any tunnel-junction although short-circuit current in the two-junction tended to decrease greatly in comparison to single-junction. Moreover, we studied the effect of film thickness of each film on the photovoltaic properties of two-junction carbon photovoltaic devices and as a result, there was a dependence of film thickness on the photovoltaic performance in the two-junction type. Thus, it can be concluded that the film thickness is one of the significant influences to enhance the photovoltaic performances and our results might be an important approach for fabricating the higher efficiency of two-junction carbon thin film photovoltaic devices made of different band gap
Finite Element Thermal Simulations for the Design of Mold Conformal Heating Channels Manufactured by 3D Printing Sand Casting for Molding of EPDM Rubber
Get PDFThis paper presents an application of Additive Manufacturing (AM) technology that is suitable for manufacturing molding tools with conformal heating channels to increase productivity for EPDM rubber molding. The design and the manufacturing of a molding tool by combining 3D sand printing and casting processes was analyzed. A simplified finite element thermal analysis was used to optimize the EPDM molding cycle time of an automotive hood seal. The simulation results showed that by using a mold with conformal heating channels manufactured by 3D printing sand casting, the cycle time process of EPDM can be reduced by 41.5%
Robust QFT-Based Position Control of an Asymmetric Hydraulic Cylinder Electro-hydraulic Servo System
Get PDFThis paper presents the design of a robust controller using the Quantitative Feedback Theory technique for an asymmetric hydraulic cylinder electro-hydraulic servo system based upon a linear, parametrically uncertain model in which some of the uncertainties reflect the variation of the parameters, and taking the external disturbance into account. After the derivation of a realistic nonlinear differential equations model, the linearized plant transfer function model is developed. The effects of parametric uncertainty are accounted for. In this paper, the tracking performance index and disturbance attenuation performance index are transformed into the constraints of the parametrically uncertain sensitivity functions respectively using the sensitivity-based QFT technique. From this point, the QFT design procedure is carried out to design a feasible robust controller that satisfies performance specifications for tracking and disturbance rejection. A nonlinear closed-loop system response is simulated using the designed controller. The results show that the robust stability against system uncertainties is achieved and the robust performances are also satisfied
Thermal Modeling and Performance Analysis of U-Tube Evacuated Solar Collector using CO2
Get PDFThis study deals with the thermal modeling of U-tube evacuated solar collectors to investigate the heat transfer and performance characteristics. The U-tube evacuated solar collectors are integrated into solar-assisted new generation experimental organic Rankine cycle working with environmentally friendly supercritical CO2. For the modeling, one-dimensional heat transfer analysis is applied to the U-tube collectors for determining the heat transfer characteristics of the collectors as well as the CO2 exit temperature from the collectors for the steady heat transfer process. Additionally, heat loss coefficient and overall heat transfer coefficients are determined for the experimental U-tube collectors. The obtained results are also compared with the results of the experimental study
Annual and Seasonal Trends of Solar Radiation in Athens, Greece
Get PDFThis study deals with the solar radiation levels recorded at the Actinometric Station of the National Observatory of Athens, focusing on the trends of the global and diffuse horizontal irradiances in the period of 1992-2017 (26 years). The analysis shows that the annual global radiation time series over Athens in the above period presents a positive trend (+0.40%/decade and +2.38%/decade for all and clear skies, respectively), while its diffuse counterpart shows negative trend (-5.19%/decade and -6.77%/decade for the same sky conditions, respectively) during the same period. Also, the seasonal trends of both solar radiation components are examined. The global horizontal radiation shows positive trends in summer (+1.85%/decade and +2.10%/decade under all and clear skies, respectively), while a negative trend is calculated in the winter season (-2.46%/decade and -1.99%/decade for the same sky conditions, respectively). In the case of the diffuse solar radiation there are found negative trends in both seasons and both sky conditions. These findings confirm a recovery in the solar radiation levels over Athens in the recent 26 years
The Combustion of Emulsified Glycerol-Heavy Oil Fuel Droplet
Get PDFIn this work the evaporation of the emulsified glycerol- heavy fuel oil (CG-HFO) droplets with different activator is modeled. The influence of activator gas bubbles volume developments on the evaporation of fuel droplets in the high temperature combustion chamber is studied. The crude glycerol as the secondary product of biodiesel production is used as the first component of the emulsion while the second component is heavy fuel oil. The crude glycerol contains methanol, aromatics, minerals, a little bit biodiesel and water. These materials were pressurized and injected in the chamber with three inputs: the first one is for the CG-HFO, the second one is for activator while the third one is for air for forming the emulsion and then passing to the combustion chamber. The applied pressure is determined according to contents which lead to flame stability of the primary formed emulation. A comparison of calculated results, basing on semi-empirical method, with experimental ones demonstrates the modeling acceptable accuracy
Motion Prediction and Risk Assessment for The Decision Making of Autonomous Vehicles
Get PDFThe last few years, the automotive industry sees the Autonomous Vehicles (AV) as a great opportunity to increase comfort and road safety. One of the most challenging tasks is to detect dangerous situations and react to avoid or, at least, mitigate accidents. This requires a prediction of the evolution of the traffic surrounding the vehicle. This paper is a survey of the methods used in Automotive engineering for predicting future trajectories and collision risk assessment. models of vehicles are classified from the simplest to the more complexes. These technologies aim to improve road safety by estimating the level of dangerousness of a situation to make decision to avoid collision or mitigate its consequences
Use of Vitreous Enamel Coated Bars in Structural Concrete Subjected to Corrosive Environment
Get PDFSteel-reinforced structural concrete is a common building material that has proven itself to be versatile, economical and affordable. Under a spectrum of operating conditions and circumstances, steel-reinforced concrete can be categorized as being both strong and durable thereby enabling in maintenance-free service during its life span. However, corrosion, or environment-induced degradation, of the steel reinforcement embedded in concrete is of concern particularly in aggressive environments, to include both aqueous and gaseous. A gradual degradation of the steel within concrete causes several problems ranging from cracking to spelling of the concrete coupled with reduced bond strength between the steel bars and the surrounding concrete. A reduction in bond strength contributes to a gradual loss in strength coupled with increased deformation, ease of initiation of flaws spanning both microscopic and macroscopic, and concurrent growth of the flaws through the microstructure. An evaluation of steel reinforcing bars coated with a new and emerging coating material is presented in this paper. Two potential applications for this type of coated bars include (a) the role of enamel-coated dowel bars for use in concrete pavements, and (b) enamel coated bars as viable reinforcement for structural concrete. The results of the study are aimed at evaluating and understanding the influence of environment on corrosion resistance of enamel coated steel reinforcing bars with concomitant influence on mechanical performance of reinforced concrete structure is presented, and comparisons are made with the performance of structural concrete reinforced with conventional steel reinforcing bars. Structural tests on beam specimens reinforced with enamel-coated steel reinforcing bars demonstrated the role of vitreous enamel coating on steel reinforcing bars and proved that the performance of reinforced concrete beams with such bars is marginally better in terms of improved flexural strength and shear strength