Comparative Study Of Experimental Results Research Articles

WITHDRAWN: Analysis of partial discharge patterns of natural ester oil and mineral oil used in power transformer

Abstract The liquid insulation used for power transformer over the years is petroleum based mineral oil because of it availability and good electrical, chemical insulation properties. However because of its poor biodegradability, low flash point and concern over environment nowadays mineral oil has been replaced with biodegradable oil. Natural ester oil is made from natural substances like soyabean, which are environment friendly, almost fire proof and have great electrical insulation properties. Partial discharge is considered to be one of the main reasons for degradation of insulations in power transformers. In this paper comparative study of experimental results of partial discharge patterns of mineral and natural ester oil are discussed. The experimental setup was designed as per IEC Standard. Power transformer insulation is modeled as pigtail specimen and tested for partial discharge behavior by applying stress more than inception voltage of mineral and natural ester oil. Phase resolved partial discharge pattern are used to analyze the results. It was found that Natural ester oil has better inception voltage compared to mineral oil and also number of partial discharge pulses and PD magnitudes are less compare to mineral oil.

Capturing Outlines of Planar Generic Images by Simultaneous Curve Fitting and Sub-division

In this paper, a new technique has been designed to capture the outline of 2D shapes using cubic B´ezier curves. The proposed technique avoids the traditional method of optimizing the global squared fitting error and emphasizes the local control of data points. A maximum error has been determined to preserve the absolute fitting error less than a criterion and it administers the process of curve subdivision. Depending on the specified maximum error, the proposed technique itself subdivides complex segments, and curve fitting is done simultaneously. A comparative study of experimental results embosses various advantages of the proposed technique such as accurate representation, low approximation errors and efficient computational complexity.

Comparative analysis of drying coffee beans using microwave and conventional oven

This article reports a comparative study of experimental results obtained during the drying of Castilla-variety coffee beans from Santander, Colombia. They were performed by two means: thermal and electromagnetic radiation. Twenty experiments were carried out, ten tests in a microwave cavity at 2,450 MHz-1,080W, and ten tests using a conventional electric oven with temperature controlled at 50±2oC. Experiments were made using samples of coffee beans with parchment, without parchment, and of the only-parchment. For each sample, dimensionless moisture ratio and diffusion coefficients were determined, according to the second law of Fick. We found that the diffusion coefficient of the samples dried in a microwave cavity was twenty-two times higher than the diffusion coefficient of samples dried with thermal radiation. Likewise, it was observed that samples in conventional oven showed a uniform temperature, in contrast with those heated by microwave radiation. Such results are useful for designing hybrid systems for drying coffee beans.

Online multi-fault detection and diagnosis for battery packs in electric vehicles

Rapid detection and accurate diagnosis of faults are essential to safe operation of battery packs in electric vehicles. However, the misdiagnosis happens occasionally because of similar signatures of cell faults, sensor faults and connection faults. In this paper, an online multi-fault diagnostic method is proposed based on a non-redundant crossed-style measurement circuit and improved correlation coefficient method. In the measurement circuit, each sensor measures the voltage sum of two neighboring cells and one connection part without increasing the hardware cost. The correlation coefficient method is used to catch fault signatures and assess the fault degree. By applying these two methods, the cell faults can be distinguished from other faults by identifying the correlation coefficient of neighboring voltages with fault flags. Furthermore, connection faults and voltage sensor faults are isolated by the correlation coefficient of the neighboring voltages difference and current. The multi-fault diagnostic method can avoid false fault detection among different faults, and ensure high robustness to normal measurement errors and battery inconsistencies of ambient temperature, state of charge, and state of health. The feasibility and advantage are validated by theoretical analysis and comparative study of experimental results.

Measurement of neutron induced 86Sr(n, 2n)85Sr reaction cross sections at different neutron energies

The cross-sections for 86Sr (n, 2n)85Sr reaction are measured at neutron energies 19.44 ± 1.02 MeV and 16.81 ± 0.85 MeV wherein there is scarcity of data. The standard neutron activation analysis technique and offline gamma ray spectroscopy have been employed for measurement and analysis of the data. The results are compared with experimental data available in EXFOR database, JEFF-3.3, JENDL-4.0, TENDL-2017 and ENDF/B-VIII.0 evaluated data. The theoretical prediction was incorporated using nuclear modular codes TALYS 1.8 and EMPIRE 3.2.2. A detailed comparative study of experimental results with the theoretical models and various major evaluations has been presented.

A composite iterative procedure with fast convergence rate for the progressive-iteration approximation of curves

The progressive iterative approximation (PIA) is an iterative method for solving the linear system of equations corresponding to the interpolation problem. In this paper, a composite iterative procedure for the progressive and iteration approximation is presented. The proposed method generates a sequence of matrices based on the Schulz iterative method which it uses in the adjusting vectors. The present method develops the progressive and iterative approximation for least square fitting (LSPIA) given in Deng and Lin (2014) and analyzes its convergence along with the estimation of error bounds. A comparative study of experimental results embosses various advantages of the proposed technique such as faster convergence rate and low approximation errors.

Investigating Efficacy of Cu Nano‐Particles as Additive for Bio‐Lubricants

Use of nano‐materials as lubricant additives is gaining tremendous importance due to their capabilities in enhancing the tribo‐performance. The nano‐particles of various elements and compounds are efficiently blended in mineral base oils enhancing their physico‐chemical as well as tribological properties. However, in recent times due to the environmental concerns, focus is being shifted toward bio based lubricants. Bio lubricants are obtained from plant oil by various chemical modification techniques. They are environment friendly, biodegradable and have better lubricating properties than the mineral oil based counterparts. The major challenge however for these lubricants is the selection of appropriate additives. The commercial additives developed for mineral base oils are generally toxic and not suitable for the Biolubricants. In this context, the present paper attempts to investigate the efficacy of Cu nano‐particles as additive for Biolubricants. The non‐edible karanja oil has been chemically modified to karanja ester and used as biolubricant. The functionalized Cu nano‐particles have been blended in various concentrations in biolubricant and the tribological performance investigated using four ball tribo‐tester. In order to ascertain the efficacy of Cu nano‐particles as additives, the tribo‐performance of Cu nano‐particle blended biolubricant has been compared with that of Zinc dialkyl dithio phosphate (ZDDP) blended biolubricant in equal concentrations. ZDDP is a conventional commercially available multi‐purpose additive that enhances the tribo‐performance of lubricating oils. The comparative study of experimental results showed that ZDDP helps in enhancing the anti‐wear performance of bio‐lubricant while the Cu nano‐particles aided in enhancement of anti‐friction behavior of biolubricant.

Assessment of multifragmentation under the effect of symmetry energy

We study the effect of symmetry energy on the fragment production for the reactions 2010Ne10+2010Ne10 and 19779Au118 + 19779Au118 for the incident energy range of 50–1000 MeV/nucleon using isospin-dependent quantum molecular dynamics (IQMD) model. Our study shows that the density-dependent symmetry energy plays a significant role in multiplicity of fragments produced at low energy. Moreover, sensitivity of density-dependent symmetry energy decreases with increase in neutron content of colliding system. We also compare the symmetry energy suggested by different groups. A comparative study of experimental results with theoretical calculations of IQMD shows that the density-dependent symmetry energy is a good probe to explain the multiplicity of the fragments at low energy.

SHEAR FAILURE OF RC MEMBERS SUBJECTED TO PRE-CRACKS AND COMBINED AXIAL TENSION AND SHEAR

The effect of loading path on the behavior of RC members is investigated. The shear capacity of RC members under coupled axial tension-shear is discussed. Three main effects of axial tension are (1) early yielding of main bar due to initial stress; (2) axial tensile stress accelerates the formation of diagonal crack and (3) pre-cracks caused by axial tension blunt the localization of diagonal cracks. The increase or decrease in shear capacity is possible depending on the relative effect of these three factors. JSCE design code seems to recognize only the first factor without explicit coverage of the second and the third ones. Comparative study of experimental results, JSCE and FEM predictions is conducted.