scholarly journals Modelling of Moisture Sorption by Cfrp Rebars with Vinylester Matrix

2004 ◽  
Vol 13 (6) ◽  
pp. 096369350401300 ◽  
Author(s):  
Olesja Starkova ◽  
Andrey Aniskevich
Keyword(s):  
Moisture Sorption ◽  
Sorption Process ◽  
Suggested Model ◽  
Sorption Data ◽  
High Anisotropy ◽  
Three Phase ◽  
Anisotropy Effect ◽  
Diffusion Character ◽  
Two Phases ◽  
Experimental Values

The results of experimental investigation and modelling of moisture sorption by CFRP rebars and vinylester matrix are presented. Experimental values of the rebar diffusion coefficients essentially differ from those predicted using structural approach. Essential anisotropy of sorption process in longitudinal and transverse directions is observed. Quasi three phase model is suggested for description of the CFRP rebar sorption. The model is based on consideration of sorption process of the diffusion character in the composite consisted of two phases: resin and microplastic, which includes fibres and fibre-resin interphase. The suggested model describes the experimental sorption data quite satisfactorily and explains high anisotropy effect.

Direct Current Deadbeat Predictive Controller for BLDC Motor Using Single DC-Link Current Sensor

2020 ◽  
Vol 38 (8A) ◽  
pp. 1187-1199
Author(s):  
Qaed M. Ali ◽  
Mohammed M. Ezzalden
Keyword(s):  
Control System ◽  
High Speed ◽  
Fast Response ◽  
Bldc Motor ◽  
Current Controller ◽  
Three Phase ◽  
Predictive Controller ◽  
Two Phases ◽  
Dc Current ◽  
Three Phase Inverter

BLDC motors are characterized by electronic commutation, which is performed by using an electric three-phase inverter. The direct control system of the BLDC motor consists of double loops; including the inner-loop for current regulating and outer-loop for speed control. The operation of the current controller requires feedback of motor currents; the conventional current controller uses two current sensors on the ac side of the inverter to measure the currents of two phases, while the third current would be accordingly calculated. These two sensors should have the same characteristics, to achieve balanced current measurements. It should be noted that the sensitivity of these sensors changes with time. In the case of one sensor fails, both of them must be replaced. To overcome this problem, it is preferable to use one sensor instead of two. The proposed control system is based on a deadbeat predictive controller, which is used to regulate the DC current of the BLDC motor. Such a controller can be considered as digital controller mode, which has fast response, high precision and can be easily implemented with microprocessor. The proposed control system has been simulated using Matlab software, and the system is tested at a different operating condition such as low speed and high speed.

scholarly journals A Three-Phase Fundamental Diagram from Three-Dimensional Traffic Data

Axioms ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 17
Author(s):  
Maria Laura Delle Delle Monache ◽  
Karen Chi ◽  
Yong Chen ◽  
Paola Goatin ◽  
Ke Han ◽  
...  
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Time Estimation ◽  
Travel Time Estimation ◽  
Traffic Data ◽  
Fundamental Diagram ◽  
Model Based Clustering ◽  
Three Phase ◽  
Characterization Of Solutions ◽  
Two Phases

This paper uses empirical traffic data collected from three locations in Europe and the US to reveal a three-phase fundamental diagram with two phases located in the uncongested regime. Model-based clustering, hypothesis testing and regression analyses are applied to the speed–flow–occupancy relationship represented in the three-dimensional space to rigorously validate the three phases and identify their gaps. The finding is consistent across the aforementioned different geographical locations. Accordingly, we propose a three-phase macroscopic traffic flow model and a characterization of solutions to the Riemann problems. This work identifies critical structures in the fundamental diagram that are typically ignored in first- and higher-order models and could significantly impact travel time estimation on highways.

Sorption Profile and Thermodynamic Characteristics of Nitrosonaphthol Functionalized Sorbent for Metal Ion Enrichment

2005 ◽  
Vol 70 (9) ◽  
pp. 1341-1356 ◽  
Author(s):  
Saima Q. Memon ◽  
Muhammad I. Bhanger ◽  
Muhammad Y. Khuhawar
Keyword(s):  
Metal Ion ◽  
Tap Water ◽  
Thermodynamic Characteristics ◽  
Chelating Agent ◽  
Standard Addition ◽  
Absorption Spectrometry ◽  
Sorption Data ◽  
Maximum Sorption ◽  
Styrene Divinylbenzene ◽  
Two Phases

A simple and reliable method has been developed using styrene-divinylbenzene-based polymeric material containing 1-nitroso-2-naphthol as chelating agent, to concentrate ultratrace amounts of Ni(II) and Cu(II) ions in aqueous samples. Sorption of both the ions on the new synthetic resin under static and dynamic conditions has been investigated. The sorption has been optimized with respect to pH, shaking and contact time of two phases. Maximum sorption has been achieved from solution of pH 5-8 after 8 min of agitation. Total saturation capacities were 516 ± 2 and 316 ± 2.5 μmol g-1 for Ni(II) and Cu(II) ions, respectively. The lowest concentration for quantitative recovery (98 ± 1%) is 1.33 and 5 ppb with the preconcentration factor of 750 and 200 for Ni(II) and Cu(II), respectively. Monitoring of the influence of diverse ions on the sorption of metal ions has revealed that phosphate, hydrogencarbonate and citrate reduce the sorption to some extent. Under optimum conditions the sorption data followed Langmuir, Freundlich, and Dubinin-Radushkevich isotherms. The kinetics and thermodynamics of sorption are studied in detail. The sorption procedure is utilized to preconcentrate these ions prior to their determination in tea, human hair, and tap water samples by atomic absorption spectrometry using direct and standard addition methods.

Analysis of a Three-Phase Buck-Boost AC Chopper Controlled in Two Phases

2007 ◽  
Author(s):  
Shinichiro Fujikura ◽  
Akiteru Ueda ◽  
Akihiro Torii ◽  
Nariaki Kobayashi
Keyword(s):  
Three Phase ◽  
Two Phases

A Comparative Sorption Study of Ni (II) form Aqueous Solution Using Silica Gel, Amberlite IR-120 and Sawdust

2019 ◽  
Vol 233 (9) ◽  
pp. 1275-1292 ◽  
Author(s):  
Atta ul Haq ◽  
Muhammad Rasul Jan ◽  
Jasmin Shah ◽  
Maria Sadia ◽  
Muhammad Saeed
Keyword(s):  
Sorption Capacity ◽  
Silica Gel ◽  
Low Cost ◽  
Sorption Process ◽  
Second Order ◽  
Order Kinetic ◽  
Sorption Data ◽  
Desorption Study ◽  
Pseudo Second Order ◽  
Sorption Study

Abstract The presence of heavy metals in water causes serious problems and their treatment before incorporating into the water body is a challenge for researchers. The present study was conducted to compare the sorption study of Ni (II) using silica gel, amberlite IR-120 and sawdust of mulberry wood in batch system under the influence of pH, initial Ni (II) concentration and contact time. It was observed that sorption process was depending upon pH and maximum sorption was achieved at pH 7.0. Kinetic data were well fitted into pseudo-second order kinetic model due to high R2 values and closeness of experimental sorption capacity and calculated sorption capacity of pseudo-second order. Isotherms study showed that Langmuir is one of the most suitable choices to explain sorption data due to high R2 values. The monolayer sorption capacities of silica gel, amberlite IR-120 and sawdust were found to be 33.33, 25.19, and 33.67 mg g−1, respectively. Desorption study revealed that NaCl is one of the most appropriate desorbent. It may be concluded from this study that sawdust is a suitable sorbent due to low cost, abundant availability and recycling of the materials for further study.

Activity coefficients, densities, dipole moments, and surface tensions of the system triethylamine–methylethylketone–water

1981 ◽  
Vol 59 (1) ◽  
pp. 127-131 ◽  
Author(s):  
Alan N. Campbell
Keyword(s):  
Surface Layer ◽  
Dipole Moments ◽  
Phase System ◽  
Constant Composition ◽  
Two Phase ◽  
Three Phase ◽  
Wide Range ◽  
Isothermal System ◽  
Total Composition ◽  
Two Phases

The properties named in the title have been determined by standard methods. Viscosity, molar volume, and orientation polarisation all indicate abnormalities of the nature of association between the components.The most interesting result is that of surface tension which indicates that, in the case of the binary system triethylamine–water, a surface layer of constant composition is formed over a wide range of total composition. When, by a rise in temperature of two or three degrees, this layer becomes unstable, it splits into two phases of different composition. The surface layer may then be instantaneously reformed and so on. A mechanism for the generation of a two-phase system is thus established. The data for the three-phase, isothermal, system are not so convincing, for reasons that are suggested.

scholarly journals Adsorption of Reactive Black M-2R on Different Deacetylation Degree Chitosan

2011 ◽  
Vol 6 (3) ◽  
pp. 155892501100600 ◽  
Author(s):  
Fang Li ◽  
Chunmei Ding
Keyword(s):  
Sorption Process ◽  
Order Kinetic ◽  
Sorption Data ◽  
Kinetic Experiment ◽  
Isotherm Equation ◽  
Degree Of Deacetylation ◽  
Deacetylation Degree ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Effects Of Temperature

Different degree of deacetylation (DD) chitosan was prepared and used for the removal of a Reactive black M-2R (RBM) from aqueous solution. The effects of temperature (298 K~323 K), chitosan dosage, degree of deacetylation on RBM removal were investigated. The adsorption equilibrium was reached within one hour. In order to determine the adsorption capacity, the sorption data were analyzed by using linear form of Langmuir, Freundlich and Tempkin isotherm equation. Langmuir equation shows higher conformity than the other two equations. From the kinetic experiment data, it was found that the sorption process follows the pseudo-second-order kinetic model. Activation energy value for sorption process was found to be 58.28 kJ mol-1. Chitosan with 66% deacetylation degree (DD) exhibited good adsorption performance for RBM. In order to determine the interactions between RBM and chitosan, FTIR analysis was also conducted.

scholarly journals A Novel Driving Scheme for Three-Phase Bearingless Induction Machine with Split Winding

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4930
Author(s):  
Francisco Elvis Carvalho Souza ◽  
Werbet Silva ◽  
Andrés Ortiz Salazar ◽  
José Paiva ◽  
Diego Moura ◽  
...  
Keyword(s):  
Control System ◽  
Digital Signal Processor ◽  
Position Control ◽  
Radial Position ◽  
Three Phase ◽  
Control Configuration ◽  
Two Phases ◽  
Split Winding ◽  
Drive And Control ◽  
And Control

In order to reduce the costs of implementing the radial position control system of a three-phase bearingless machine with split winding, this article proposes a driving method that uses only two phases of the system instead of the three-phase traditional one. It reduces from six to four the number of inverter legs, drivers, sensors, and current controllers necessary to drive and control the system. To justify the proposal, this new power and control configuration was applied to a 250 W machine controlled by a digital signal processor (DSP). The results obtained demonstrated that it is possible to carry out the radial position control through two phases, without loss of performance in relation to the conventional three-phase drive and control system.

An Analytical Model for the Effective Dielectric Constant of a 0-3-0 Composite

2010 ◽  
Author(s):  
K. A. Cook-Chennault ◽  
S. Banerjee
Keyword(s):  
Dielectric Constant ◽  
Aspect Ratio ◽  
Analytical Model ◽  
Experimental Results ◽  
Effective Dielectric Constant ◽  
The Third ◽  
Third Phase ◽  
Three Phase ◽  
Phase 0 ◽  
Experimental Values

An analytical expression for prediction of the effective dielectric constant of a three phase 0-3-0 ferroelectric composite is presented. The analytical results are verified with the experimental results from Nan et al [1]. We extend the analytical model, so that the influence of the shape of the third phase inclusion, on the effective dielectric constant of the composite, can be investigated. The results indicate that the dielectric constant increases ∼7 times, when the aspect ratio of the conductive inclusion is increased from 1 (sphere) to 10 (spheroid). The analytical predictions compare favorably with the experimental values.

A superamphiphobic surface with a hydrogen peroxide-triggered switch to antithetic fluid repellence in a liquid–liquid–air three-phase fluid system

2020 ◽  
Vol 56 (31) ◽  
pp. 4312-4315
Author(s):  
Yihan Sun ◽  
Jinxia Huang ◽  
Zhiguang Guo
Keyword(s):  
Hydrogen Peroxide ◽  
The Other ◽  
Fluid System ◽  
System P ◽  
Arbitrary Phase ◽  
Three Phase ◽  
Air System ◽  
Two Phases ◽  
Phase Fluid

Fluid repellence in one arbitrary phase for repelling the other two phases in a generalized liquid–liquid–air system was achieved on a hydrogen peroxide-treated surface.

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