Fuzzy decorrelating detector for non-Gaussian CDMA channel

A fuzzy decorrelating detector for CDMA non-Gaussian channels is proposed. The proposed scheme combines a linear decorrelator with a nonlinear preprocessor based on fuzzy logic and rank ordering that is incorporated to combat impulsive noise. Simulation results show that the proposed technique is very robust in combating impulsive noise.     

Applied whispering gallery modes on ZnO nanorods coated glass for humidity sensing application

In this letter, a humidity sensor is demonstrated by applying a whispering gallery mode (WGM) from a microsphere resonator onto the ZnO nanorods coated glass surface. The diameter of the microsphere was 234 µm and the glass surface was coated with ZnO nanorods using the hydrothermal method at growth duration of 12 h. A significant response to humidity level ranging from 35%RH to 85%RH has been observed with the sensitivity of 0.014 2 nm/%RH. The proposed humidity sensor has successfully employed to enhance interaction between the whispering gallery mode evanescent and surrounds analyte with the assistance of ZnO nanorods coated glass.     

Hybrid multi-verse optimizer with grey wolf optimizer for power scheduling problem in smart home using IoT

The Journal of Supercomputing - The power scheduling problem in smart home (PSPSH) is one of the complex NP-hard scheduling problems, where it has a deep and rugged search space due to the high...     

Human action recognition: a framework of statistical weighted segmentation and rank correlation-based selection

Pattern Analysis and Applications - Human action recognition from a video sequence has received much attention lately in the field of computer vision due to its range of applications in...     

Re-refining of used lubricant oil by solvent extraction using central composite design method

The primary aim of this study was to recover base oil from used oil using solvent extraction followed by the adsorption method. Many effective variables were examined within the solvent extraction method, including using different solvents, solvent/used oil, temperature and speed of blending. Central composite design (CCD) was applied as the statistical method. Response surface methodology was then used to find the optimum conditions in the process of extraction: ratio of solvent/used oil 2.4 and 3.12 vol/vol, temperature=54 and 18 °C, and speed of mixing=569 and 739 rpm for 1-butanol and methyl ethyl ketone (MEK), respectively. Various flocculation agents were used with the solvent, such as Sodium hydroxide (NaOH), Potassium hydroxide (KOH) and Monoethylamine (MEA); they provided an increase in the separation efficiency. The best result was obtained when using 2 grams of MEA/kg solvent; this amount of MEA increases sludge removal from 12.6% to 14.7%. In the process of clay adsorption, the variables that were tested included the ratio of clay/extract oil, temperature and time of contact. The best conditions in the process of adsorption by activated bentonite were a ratio of clay/extract oil=15 wt/vol%, temperature=120 °C, and time of contact=150 minutes. The recovered base oil was analyzed by Fourier transform infrared spectroscopy (FTIR) and compared to Iraqi specifications of base oils. The recovered base oil specifications were analyzed, including, viscosity @100 °C 8.32, 9.22 cSt, pour point ?17.35, ?22.23 °C, flash point 210.12, 223.04 °C, total acid number (TAN) 0.25, nill, total base number (TBN) nill, nill, ash 0.031, 0.0019 wt% and color 3.0, 2.5 for two types of base oil recovered using MEK, 1-butanol with activated bentonite, respectively.     

Synthesis and microstructural characterization of low to high molecular weight poly(vinylphosphonic acid)s: effect of molecular weight and temperature on acidity and polyelectrolyte behavior

Poly(vinylphosphonic acid) (PVPA) was synthesized by free radical polymerization of vinylphosphonic acid (VPA) in different solvents. Bromotrichloromethane as a chain transfer agent (CTA) was used in some experiments to control molecular weight of the PVPA. The effects of solvent type and initiator and CTA concentrations on the microstructure, molecular weight and stereoregularity of the resulting PVPA was extensively investigated by FTIR, ¹HNMR, ³¹PNMR and elemental analysis. Polymers with a number-average molecular weight (M_n) in the range of 1550 to 42,190 gmol^?1 were prepared. High molecular weight PVPA with M_n of 42,190 gmol^?1 was obtained from aqueous solution polymerization of VPA with initiator/monomer molar ratio of 0.16/100 at 80°C. Molecular weight decreased with increasing the concentration of initiator and CTA. ¹HNMR spectra were used to investigate tetrad sequences for the methylene protons of PVPA, from which stereochemical information of the polymer chain was obtained. Tetrad sequences were also calculated by Bernoullian probabilities. Moreover, the percent of head-to-head and tail-to-tail irregularities of the resulting PVPA were obtained to be in the range of 16.6–58% depending on the reaction conditions. The PVPA synthesized in acetic anhydride as a solvent had highest amount of the irregularities due to the high reaction rate, which does not allow controlling the structure. Furthermore, due to the importance of PVPA in the proton exchange membranes (PEMs), the effects of molecular weight and temperature on the acidity and titration behavior of PVPA polyelectrolyte were investigated. It was found that molecular weight has no significant effect on the acidity and dissociation of protons at operational conditions of degree of dissociation lower than 0.5. It was also found that by increasing the temperature, pH values were decreased, meaning that dissociation of protons and consequently the proton conductivity of PVPA membranes can be affected by temperature. Titration behavior of PVPA also showed that the PVPA has a behavior similar to a monoprotic acid.     

Electrical conductivity in hot-pressed nitrogen ceramics

The a.c. and d.c. electrical conductivities of some hot-pressed polycrystalline nitrogen ceramics have been measured between 400 and 1000° C. The materials examined were Si₃N₄, 5.0% MgO/Si₃N₄ and two sialons, Si_(6–z) · Al _z · O _z · N_(8–z) having z 3.2 and z 4.0 respectively. The electrical behaviour of all the materials showed similar general features. The d.c. conductivities were about 10^{–10 –1} cm^–1 at 400° C and rose to between 10^–6 and 10^{–5 –1} cm^–1 at 1000° C. The a.c. Data, taken over the frequency range 15 Hz to 5 kHz showed that below about 500° C the a.c. conductivity ( _a.c.) varied with frequency as _a.c. ^s where 0.7 _d.c.) agreed well with the relation _d.c. = A exp(–B/T ^1/4). Above 700° C both the a.c. and d.c. conductivities followed log T ^–1. Hall effect and thermoelectric power measurements enabled the Hall mobility to be estimated as less than 10^–4 cm² V^–1 sec^–1 at 400° C and showed that the materials were all p-type below 900° C and n-type above 900° C. The electrical properties of all four materials are consistent with the presence of a glassy phase.