scholarly journals Snow Melting Performance of Graphene Composite Conductive Concrete in Severe Cold Environment

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6715
Author(s):  
Xinjie Wang ◽  
Yongkang Wu ◽  
Pinghua Zhu ◽  
Tao Ning
Keyword(s):  
High Efficiency ◽  
Concrete Slab ◽  
Input Voltage ◽  
Electrode Spacing ◽  
Snow Melting ◽  
Electric Voltage ◽  
Cold Regions ◽  
Graphene Composite ◽  
Time Required ◽  
Snow Thickness

The use of conductive concrete is an effective way to address snow and ice accretion on roads in cold regions because of its energy saving and high efficiency without interruption of traffic. Composite conductive concrete was prepared using graphene, carbon fiber, and steel fiber, and the optimum dosage of graphene was explored with resistivity as the criterion. Subsequently, under the conditions of an initial temperature of −15 °C and a wind speed of 20 km/h, the extremely severe snow event environment in cold regions was simulated. The effects of electrode spacing and electric voltage on snow melting performance of conductive concrete slab were explored. Results showed that graphene can significantly improve the conductivity of conductive concrete; the optimal content of graphene was 0.4% of cement mass in terms of resistivity. The snow-melting power of conductive concrete slab decreased with increase in electrode spacing and increased with increase in on-voltage. For an optimal input voltage of 156 V and an optimal electrode spacing of 10 cm, the time required to melt a 24 h snow thickness (21 cm), accumulated during a simulated severe snow event, was only 2 h, which provides an empirical basis for the application of graphene composite conductive concrete to pavement snow melting in cold regions.

scholarly journals Effect of the Geometrical Constraints to the Wenner Four-Point Electrical Resistivity Test of Reinforced Concrete Slabs

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4622
Author(s):  
Kevin Paolo V. Robles ◽  
Jurng-Jae Yee ◽  
Seong-Hoon Kee
Keyword(s):  
Experimental Investigation ◽  
Electrical Resistivity ◽  
Reinforced Concrete ◽  
Concrete Slab ◽  
Plain Concrete ◽  
Electrode Spacing ◽  
Concrete Slabs ◽  
Reinforced Concrete Slabs ◽  
Spacing Ratio ◽  
Geometrical Constraints

The main objectives of this study are to evaluate the effect of geometrical constraints of plain concrete and reinforced concrete slabs on the Wenner four-point concrete electrical resistivity (ER) test through numerical and experimental investigation and to propose measurement recommendations for laboratory and field specimens. First, a series of numerical simulations was performed using a 3D finite element model to investigate the effects of geometrical constraints (the dimension of concrete slabs, the electrode spacing and configuration, and the distance of the electrode to the edges of concrete slabs) on ER measurements of concrete. Next, a reinforced concrete slab specimen (1500 mm (width) by 1500 mm (length) by 300 mm (thickness)) was used for experimental investigation and validation of the numerical simulation results. Based on the analytical and experimental results, it is concluded that measured ER values of regularly shaped concrete elements are strongly dependent on the distance-to-spacing ratio of ER probes (i.e., distance of the electrode in ER probes to the edges and/or the bottom of the concrete slabs normalized by the electrode spacing). For the plain concrete, it is inferred that the thickness of the concrete member should be at least three times the electrode spacing. In addition, the distance should be more than twice the electrode spacing to make the edge effect almost negligible. It is observed that the findings from the plain concrete are also valid for the reinforced concrete. However, for the reinforced concrete, the ER values are also affected by the presence of reinforcing steel and saturation of concrete, which could cause disruptions in ER measurements

scholarly journals A Modified High Voltage Gain SEPIC Based DC-DC Converter with Continuous Conduction Mode

2020 ◽  
Vol 6 (12) ◽  
pp. 268-274
Author(s):  
G.Vijaykumar and Dr.V.Geetha
Keyword(s):  
High Voltage ◽  
High Efficiency ◽  
Input Voltage ◽  
Voltage Gain ◽  
Pv System ◽  
Operating Modes ◽  
High Voltage Gain ◽  
Voltage Stress ◽  
High Output Voltage ◽  
High Output

A high voltage gain modified SEPIC converter is proposed in this paper. This proposed converter has many advantages i.e., high output voltage, lower voltage stress, high efficiency, voltage gain is high without any coupled inductor and transformer, continuous input current. Thus, there is no overshoot voltage at turn-off process for switches. By using single switches, the CCM mode operation can be easily controlled by this converter, so control system is simple and also wide output values is obtained only by modifying the duty cycle. This modified converter has lower components than conventional converter. The operating modes and design of modified converter are discussed. The output power of this converter is 6 watts. By this converter, this converter capable of developing the two and half times of input voltage. The PV system also used this converter to develop high voltage gain. This high voltage gain is achieved by using MATLAB/SIMULIMK platform.

scholarly journals High gain boost converter with modified voltage multiplier for stand alone PV system

2019 ◽  
Vol 14 (1) ◽  
pp. 185
Author(s):  
Getzial Anbu Mani ◽  
A. K. Parvathy
Keyword(s):  
High Efficiency ◽  
Input Voltage ◽  
High Gain ◽  
Boost Converter ◽  
Pv System ◽  
Boost Converters ◽  
Low Input ◽  
Voltage Multiplier ◽  
Photo Voltaic ◽  
Current Ripple

<p>Boost converters of high gain are used for photo voltaic systems to obtain high efficiency. These high gain Boost converters gives increased output voltage for a low input produces high outputs for low input voltage. The High gain boost converters have the following merits. Conduction losses input current ripple and stress across the switches is reduced while the efficiency is increases. The high gain of the converters with the above said merits is obtained by changing the duty cycle of switches accordingly .In this paper a boost converter working with interleaved concept along with a additional Nstage voltage Multiplier has been carried out by simulation using MATLAB/ simulink and the mathematical modeling of various parameters is also done.</p>

scholarly journals Research on Key Technology of Electrochemical Sterilization and Physical Application for Circulating Cooling Water

2021 ◽  
Vol 2083 (2) ◽  
pp. 022068
Author(s):  
Xiaohui Wang ◽  
Chunyan Song ◽  
Xueying Xie ◽  
Nan Zhang ◽  
Ruiqing Guo ◽  
...  
Keyword(s):  
Electric Fields ◽  
Electrode Materials ◽  
High Efficiency ◽  
Thermal Power ◽  
Cooling Water ◽  
Environmentally Friendly ◽  
Research Progress ◽  
Electrode Spacing ◽  
Experimental Conditions ◽  
Circulating Cooling Water

Abstract As a high-efficiency, low-cost, convenient and environmentally friendly sterilization technology, electrochemical disinfection has developed rapidly in recent years. Electrochemical sterilization is an environmentally friendly sterilization technology. The research progress of this technology in the recent 30 years in sterilization mechanism and electrode materials is summarized. The mechanism of electrochemical sterilization includes the chemical effects of active chlorine, active intermediates, copper or silver ions, and the physical effects of electric fields; the electrode materials used are titanium anode, carbon cathode, and anode. The article combined with electrochemical equipment in a thermal power plant cold open circulating cooling water treatment experiment. Experimental research found that under the conditions of current density of 120A/m2, residence time of 10s, and electrode spacing of 1.8cm, the bactericidal effect can reach 97%. Under certain experimental conditions and a certain period of time, the total number of heterogeneous bacteria in the circulating cooling water after treatment can be effectively inhibited.

scholarly journals Resonant Hybrid Flyback, a New Topology for High Density Power Adaptors

Electronics ◽  
2018 ◽  
Vol 7 (12) ◽  
pp. 363 ◽  
Author(s):  
Alfredo Medina-Garcia ◽  
Manfred Schlenk ◽  
Diego Morales ◽  
Noel Rodriguez
Keyword(s):  
Power Density ◽  
Pulse Width Modulation ◽  
High Efficiency ◽  
Full Range ◽  
Input Voltage ◽  
Zero Voltage Switching ◽  
Zero Current Switching ◽  
Zero Current ◽  
Class Power ◽  
World Class

In this article, an innovative power adaptor based on the asymmetrical pulse width modulation (PWM) flyback topology will be presented. Its benefits compared to other state-of-the-art topologies, such as the active clamp flyback, are analyzed in detail. It will also describe the control methods to achieve high efficiency and power density using zero-voltage switching (ZVS) and zero-current switching (ZCS) techniques over the full range of the input voltage and the output load, providing comprehensive guidelines for the practical design. Finally, we demonstrate the convenience of the proposed design methods with a 65 W adaptor prototype achieving a peak efficiency of close to 95% and a minimum efficiency of 93.4% at full load over the range of the input voltage, as well as a world-class power density of 22 W/inch3 cased.

scholarly journals Impact of Transformer Turns Ratio on the Power Losses and Efficiency of the Wide Range Isolated Buck–Boost Converter for Photovoltaic Applications

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5645
Author(s):  
Hamed Mashinchi Maheri ◽  
Dmitri Vinnikov ◽  
Andrii Chub ◽  
Vadim Sidorov ◽  
Elizaveta Liivik
Keyword(s):  
High Efficiency ◽  
Input Voltage ◽  
Power Losses ◽  
Efficient Operation ◽  
Wide Range ◽  
Photovoltaic Applications ◽  
Theoretical Predictions ◽  
Converter Topology ◽  
Isolation Transformer ◽  
The Impact

In this paper, the impact of transformer turns ratio on the performance of the quasi-Z-source galvanically isolated DC-DC converters is studied. Embedded buck–boost functionality enables these converters to regulate the input voltage and load in a wide range, which makes them suitable for such demanding application as photovoltaic microconverters. The isolation transformer here plays a central role as its turns ratio defines the point of transition between the boost and buck modes and overall capability of the converter to regulate the input voltage in a wide range at high efficiency. The studied quasi-Z-source galvanically isolated DC-DC converter is benchmarked in terms of power loss of components and weighted power conversion efficiency for three different turns ratios of isolation transformer to achieve the best and optimized turns ratio lead to the efficient operation. Operation in a wide range of input voltage at high efficiency is the main criterion for assessing the effect of turns ratio on the efficiency of the converter. The proposed loss model and theoretical predictions of the efficiency were validated with the help of a 300 W experimental prototype of the photovoltaic microconverter based on the quasi-Z-source galvanically isolated DC-DC converter topology.

scholarly journals Effects of loading contact on electric-power generation of lead zirconate titanate piezoelectric ceramic plate

2019 ◽  
Vol 8 (4) ◽  
pp. 509-518 ◽  
Author(s):  
Mitsuhiro Okayasu ◽  
Tsukasa Ogawa
Keyword(s):  
Power Generation ◽  
Electric Power ◽  
Lead Zirconate Titanate ◽  
Contact Area ◽  
High Efficiency ◽  
Lead Zirconate ◽  
Ceramic Plate ◽  
Electric Power Generation ◽  
Electric Voltage ◽  
Pzt Ceramic

AbstractTo better understand the generation of electric power for piezoelectric PbZrTiO3 (PZT) ceramic plate (ϕ25 mm), an attempt was made to investigate experimentally and numerically electric- power generation characteristics during cyclic bending under various loading fixtures (ϕ0–ϕ20 mm), i.e., different contact areas. Increasing the load-contact area on the PZT ceramic leads to a nonlinear decrease in the generated voltage. Decreasing contact area basically enhances the generated voltage, although the voltage saturates during loading when the contact area is less than ϕ5 mm. A similar voltage is generated for ϕ0 and ϕ5 mm, which is attributed to strain status (ratio of compressive and tensile strain) and material failure due to different stress distribution in the PZT ceramic. On the basis of the obtained electric generation voltage, suitable loading conditions are clarified by loading with the ϕ5 mm fixture, which generates a higher voltage and a longer lifetime of the PZT ceramic. From this approach, it is appeared that the area contact with the area ratio of 0.04 (ϕ5 mm/ϕ20 mm) is suitable to obtain the high efficiency of the electric voltage.

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