Predicting the Delamination Mechanisms of Multidirectional Laminates Using the Energy Release Rate Obtained from AE Monitoring

This study investigates delamination damage mechanisms during the double cantilever beam standard test using the strain energy release rate. The acoustic emission parameter is used to replace the original calculation method of measuring crack length to predict delamination. For this purpose, 24-layer glass/epoxy multidirectional specimens with different layups, and interface orientations of 0°, 30°, 45°, and 60°, were fabricated based on ASTM D5528 (2013). Acoustic emission testing (AE) is used to detect the damage mechanism of composite multidirectional laminates (combined with microscopic real-time observation), and it is verified that the strain energy release rate can be used as a criterion for predicting delamination damage in composite materials. By comparing the AE results with the delamination expansion images observed by microvisualization in real time, it is found that the acoustic emission parameters can predict the damage of laminates earlier. Based on the data inversion of the acoustic emission parameters of the strain energy release rate, it is found that the strain energy release rate of the specimens with different fiber interface orientations is consistent with the original calculated results.

​Mathematical Modeling and Optimization for Emission Parameter SO2 of Dual Fuel CI Engine using Mustard Stalk

Background: Punjab (India) an agricultural state with twelve major crops sown round the year, produces 14.53 MT as crop residue. This huge quantity of crop residue poses a serious problem of stubble burning in the fields, leading to an alarming level of air pollution across the state, along with a potential loss of fuel usable for power generation. About 1000 MW of electricity can be generated from this crop residue by the proper utilization (Singh et al. 2015). Methods: Characteristics of various crop residues were evaluated experimentally and further investigations have been carried out to study the performance of producer gas derived from mustard stalk using a downdraft gasifier in combination with diesel oil in dual fuel diesel engine, where effect of various input parameters such as type of fuel, equivalence ratio and load on engine were studied on emission component SO2. Results were modeled and optimized through central composite design (CCD) of response surface methodology (RSM) using design of experiments technique to determine the most desirable mode of utilization. Result: It has been found that fixed carbon (40.55%), sulphur (0.367%), moisture contents (6.88%) and nitrogen contents (1.314%) in mustard stalk is almost same as in coal, where as hydrogen (6.124%), oxygen (43.965%), volatile matter (68.93%), gross calorific values (3933 kcal/kg) of mustard stalk are more and ash content (6.65%) is less as compared to corresponding values for coal. In all the three modes of operations, SO2 increases with increase in load on the engine. ER has no effect in diesel alone mode but in dual modes with increase in ER further increases SO2 as high temperature producer gas and air along with sulphur enters the engine which further increases the value of SO2.

Spectroscopic study of the [O iii]λ5007 profile in Seyfert 1 galaxies

ABSTRACT The spectra of active galactic nuclei usually exhibit wings in some emission lines, such as [O iii]λλ5007, 4959, with these wings generally being blueshifted and related to strong winds and outflows. The aim of this work was to analyse the [O iii] emission lines in broad-line Seyfert 1 (BLS1) galaxies in order to detect the presence of wings, and to study the [O iii] line properties and their possible connection with the central engine. In addition, we attempted to compare the black hole mass distribution in both BLS1 galaxies with symmetric and blue-asymmetric [O iii] profiles. For this purpose, we carried out a spectroscopic study of a sample of 45 nearby southern BLS1 galaxies from the Six Degree Field Galaxy survey. The [O iii] emission lines were well-fitted using a single Gaussian function in 23 galaxies, while 22 objects presented a wing component and required a double-Gaussian decomposition. By computing the radial velocity difference between the wing and core centroids (i.e. Δv), we found 18 galaxies exhibiting blueshifted wings, 2 objects presenting red wings, and 2 galaxies showing symmetric wings (Δv = 0). Moreover, Δv was slightly correlated with the black hole mass. In addition, we computed the radial velocity difference of the blue-side full extension of the wing relative to the centroid of the core component through the blue emission parameter, which revealed a correlation with black hole mass, in agreement with previous results reported for narrow-line galaxies. Finally, in our sample, similar black hole mass distributions were observed in both BLS1 galaxies with symmetric and blueshifted asymmetric [O iii] profiles.

Characterization and analysis of the tensile and acoustic emission parameter distributions of single wool fibers

Acoustic emission (AE) parameters of damaged material have discrete characteristics that are universally known. Such characteristics restrict wider use of AE analysis in materials such as textiles. In the present work, the best-fitted distribution models of AE signal energy are analyzed: amplitude, duration, tensile breaking strength, elongation, and specific work of wool fibers. The parameters of Weibull, normal, and log-normal distribution models are obtained by regression analysis. The chi-square, Kolmogorov–Smirnov, and maximum likelihood criterions are used to discriminate against the above models. The results show that the Weibull distribution is the best-fitted model for amplitude and elongation of wool. The best-fitted model for energy, strength, and specific work is the log-normal distribution. The differences between the cumulative distributions of the AE and tensile parameters are compared. It can be seen that strength also has a high correlation coefficient and a similarly cumulative distribution with energy and amplitude. Compared to amplitude, the relationship between energy and strength is supposed to be stronger.

Performance and Emission Parameters with Blending of Jatropha Biodiesel in Diesel Engine

In the current situation limited resources of petroleum products and their higher consumption rate and pollution increase research work for an alternative option for internal combustion engines. The emissions draws from these fuels also pollute the environment more day by day. Jatropha oil from jatropha seed is one sources of biodiesel which is a less polluting, locally available and reliable renewable resource. In this research work, performance and analysis doing on 5 HP single cylinder of vertical arrangement and direct injection CI engines with rope brake dynamometer with a blending of jatropha biodiesel. The performance and emission parameter of the diesel engine were found with different proportions of biodiesel in a existing diesel fuel. The result shows that by using up to 20 % biodiesel in diesel, compatible performance parameters with reduced emissions can be achieved.

A novel acoustic emission parameter for predicting rock failure during Brazilian test based on cepstrum analysis

Acoustic emission (AE) is widely used in the monitoring of coal and rock stability and early warning of dynamic disasters in mines. In this work, the Brazilian split test was carried out on limestone samples along with collecting full waveform AE signal during the entire loading process. The linear cepstrum coefficient (LCC) was used as the characteristic parameter of AE to analyze the correlation between the LCC of AE and the load of the samples. The results show that the LCC is an effective AE characteristic parameter. The first to fourth parameters of the LCC calculated using 1 s AE waveform meet the linear change relationship with the load of the samples. The correlation coefficients are 0.969, 0.943, 0.925, 0.833, respectively. The LCC of AE proposed in this work can be used as a characteristic parameter for predicting the tensile failure of rocks, which is helpful to improve the application effect of AE in the monitoring of coal and rock dynamic disasters and the stability of high and steep slopes.