Different techniques for real time estimation of an induction motorrotor resistance in sensorless direct torque control for electricvehicle

Four different techniques for rotor resistance estimation in sensorless direct torque control (DTC) are studied and compared. Since the input voltage contains harmonics, many available techniques cannot be applied in the DTC. Three of the four above-mentioned techniques are the generalization of the previous methods. The fourth technique is a new one, which is applied by the authors. The speed of motor is estimated based on the governing equations of the induction motor and DTC. The resistance is estimated above rated speeds, which were required in electric vehicles (EVs). Although the four techniques enable to estimate the rotor resistance in real time, the new technique and TE (torque-error) method have some advantages over two other techniques     

New solid-state onload tap-changers topology for distribution transformers

High controllability advantages of power electronic switches lead to their application in the tap-changer of distribution transformers. Using such switches leads to quick operation of the tap-changer and, thus, improved performance. Moreover, their application reduces maintenance and repair costs of tap-changers. This paper introduces a new solid-state onload tap-changer topology that has many steps with fewer power electronic switches compared with those reported in the literature. This tap-changer is designed for an 800-kVA, 20-kV/400-V distribution transformer, and the results are discussed.     

Vertical distributions and gamma dose rates of 40K, 232Th, 238U and 137Cs in the selected forest soils in Izmir, Turkey

This paper presents the results obtained from a radioecological study carried out in the selected forest sites of Izmir, Turkey. The levels of gamma-emitting radionuclides, 40K, 232Th, 238U and 137Cs, in soils were determined using gamma spectroscopy. The activity profile for 40K, 232Th and 238U exhibits a uniform distribution with respect to depth. The depth distribution of 137Cs activity was established by fitting the experimental points to an exponential or a Gaussian function. About 42-97% of the 137Cs deposition was found in the first 10 cm of soil even after 18 y from Chernobyl accident. The dose-rate and annual-effective dose received from external irradiation were quantified. It is indicated that 137Cs from the fallout plays a less role in external radiation exposures in forest sites of Izmir than in potential exposures from naturally occurring radionuclides accounted for by soil.     

Design of Cyclic Prefix Characteristic-Based OFDM System for WiMAX Technology

Wireless Personal Communications - Worldwide interoperability for microwave access (WiMAX) offers the wireless connectivity using orthogonal frequency division multiplexing (OFDM) modulation is a...     

Anion conductive tetra-sulfonium hydroxides poly(fluorenylene ether sulfone) membrane for fuel cell application

A series of anion exchange membranes of poly (fluorenylene ether sulfone) containing tertiary sulfonium hydroxide-functionalized fluorenyl groups were synthesized by sequential polycondensation, chloromethylation, substitution with dimethyl sulfide and ion exchange. They showed excellent solubility in polar aprotic solvents. Consequently, flexible and tough alkaline membranes with varying ionic contents were obtained by an anion exchange of tertiary sulfonium chloride polymers with 1.0 M KOH at room temperature. Different levels of substitution were performed to achieve high ionic conductivity as well as upholding the membranes’ mechanical stability. The tertiary sulfonium membranes demonstrated lower water uptake compared to quaternary ammonium membrane. High hydroxide ion conductivity was achieved up to 18.3 mS cm^?1 at 80 °C with the membrane of the highest ion exchange capacity (IEC, 1.51 mmol g^?1). The resulting alkaline polymers were characterized by ¹H NMR, FT-IR, thermogravimetric analysis (TGA), water uptake, IEC, atomic force microscopic (AFM) images.     

Two-Stage Multi-Water Sources Allocation Model in Regional Water Resources Management under Uncertainty

Water Resources Management - Water shortages are common in society, and the effective allocation of limited water resources to each competitive sector has become one of the urgent concerns for...     

A generic model for diffusive dynamics of the substrate and fluorescein tagged enzyme in microfluidic platform

Microsystem Technologies - The aim of this study was to develop a model that describes enzymatic conversion in a microfluidic system along with convective and diffusive transport of...     

Reconstruction of Grenfell Tower fire. Part 1: Lessons from observations and determination of work hypotheses

The Grenfell Tower fire occurred on 14 June 2017, killing 72 people. The pattern and speed of vertical and horizontal fire spread characterize this catastrophic event. Plentiful video and photographic data of the fire spread available has been carefully verified and concatenated into a database. The verified data have been superimposed on a projection of the Grenfell Tower in order to track the development of the fire. The surface that is unburnt, burning, or extinguished, as well as the presence of internal fire at any given location, is thus recorded for the duration of the fire. An analysis of the results showed that the initial vertical propagation can be divided into three phases. After the façade ignited at the fourth floor, vertical propagation over time is linear, with a vertical fire spread rate of around 3.5 m/min until the fire reached the sixth floor. Then fire propagation decelerated. Finally, fire spread accelerated with a power four dependence. The maximum vertical fire spread rate was around 8 m/min as the fire reached the crown at the top of the building. Horizontal spread proved to be greatest at the level of the crown (0.293 ± 0.005 m/min). There is a linear relationship between speed of horizontal fire spread and height. These correlations and observations yield important conclusions, and eight different hypotheses capable of explaining the global behaviour of the fire are suggested.     

Effect of feeding pattern on biochemical storage by activated sludge under anoxic conditions

This study investigated the effect of feeding pattern on bacterial storage under anoxic conditions, emphasizing previous adaptation of biomass to a long term feeding condition, under steady-state operation. Storage was evaluated in a sequencing batch reactor (SBR) system operated in a sequence of anoxic/aerobic phases, fed with acetate as the sole carbon source during anoxic conditions. The experimental results indicated that biochemical storage of acetate as PHB occurred when substrate was fed as a pulse, while acetate was removed mostly through direct microbial growth under continuous feeding. For pulse feeding, the anoxic yield, Y(STOD) was calculated as 0.58mg COD (mgCOD)(-1) in two different ways, using mass balances on acetate utilization, PHB generation and nitrate consumption. This value was supported by parallel batch tests and similar results in the literature. Similarly, the rate coefficient for storage under anoxic conditions, k(STOD) was computed as 9.3day(-1) based on basic stoichiometry and model calibration of experimental data. Batch tests conducted with biomass adapted to different feeding patterns showed that substrate storage was insignificant when the feed was added continuously at low concentrations, even if the biomass was previously adapted to storage. Similarly biomass acclimated to continuous feeding could not store the excess substrate although fed instantly. For the operating conditions selected for the study, storage response was significant only with a microbial culture with metabolic activities previously adapted to storage and with short-term substrate feeding at high concentrations.