排序方式: 共有26条查询结果,搜索用时 285 毫秒
1.
M. Multani N.G. Nanadikar N. Venkataramani V. Ragupathy A.K. Pansare A. Gurjar 《Materials Research Bulletin》1979,14(10):1251-1258
Hot spraying (evaporative decomposition of solution) of sulfates of yttrium and iron at 1000°C and above produced powders which could be sintered to 99% X-ray density with homogeneous micro-structure and controlled grain size. The powder obtained from the hot-spray reactor was well gelated. However, no detectable YIG phase was obtained in the powder. The only constituents were YFeO3 and Fe2O3. This is attributed to the fast nucleation of YFeO3 phase in the reactor. The calcination studies of these powders showed that the conversion to YIG phase began above 900°C. The calcined powder with more than 90% conversion to YIG phase was still very fine and reactive. It could be sintered to high density product with average grain size ranging from 2 μ upwards. 相似文献
2.
Balakumaresan Ragupathy Manivannan Karunakaran 《International journal of imaging systems and technology》2021,31(1):379-390
This article develops a methodology for meningioma brain tumor detection process using fuzzy logic based enhancement and co‐active adaptive neuro fuzzy inference system and U‐Net convolutional neural network classification methods. The proposed meningioma tumor detection process consists of the following stages as, enhancement, feature extraction, and classifications. The enhancement of the source brain image is done using fuzzy logic and then dual tree‐complex wavelet transform is applied to this enhanced image at different levels of scale. The features are computed from the decomposed sub band images and these features are further classified using CANFIS classification method which identifies the meningioma brain image from nonmeningioma brain image. The performance of the proposed meningioma brain tumor detection and segmentation system is analyzed in terms of sensitivity, specificity, segmentation accuracy, and Dice coefficient index with detection rate. 相似文献
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This research implements a novel segmentation of mammographic mass. Three methods are proposed, namely, segmentation of mass based on iterative active contour, automatic region growing, and fully automatic mask selection-based active contour techniques. In the first method, iterative threshold is performed for manual cropped preprocessed image, and active contour is applied thereafter. To overcome manual cropping in the second method, an automatic seed selection followed by region growing is performed. Given that the result is only a few images owing to over segmentation, the third method uses a fully automatic active contour. Results of the segmentation techniques are compared with the manual markup by experts, specifically by taking the difference in their mean values. Accordingly, the difference in the mean value of the third method is 1.0853, which indicates the closeness of the segmentation. Moreover, the proposed method is compared with the existing fuzzy C means and level set methods. The automatic mass segmentation based on active contour technique results in segmentation with high accuracy. By using adaptive neuro fuzzy inference system, classification is done and results in a sensitivity of 94.73%, accuracy of 93.93%, and Mathew’s correlation coefficient (MCC) of 0.876. 相似文献
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A simple electrolytic reduction method for the preparation of beta-alanine hydrochloride using deposited palladium black over graphite is described. Beta-alanine is used for the synthesis of vitamin pantothenic acid. This electroreduction technique should be generally useful for the preparation of primary amines. 相似文献
5.
Multidimensional Systems and Signal Processing - Nowadays medical images are captured through various imaging modalities for clinical diagnosis. It is more complicated to process the images... 相似文献
6.
Soo Chool Lee Chun Yong Ryu Dhanusuraman Ragupathy Joong Beom Lee Jae Chang Kim 《Fuel》2011,90(4):1465-3842
A new regenerable alumina-modified sorbent was developed for CO2 capture at temperatures below 200 °C. The CO2 capture capacity of a potassium-based sorbent containing Al2O3 (KAlI) decreased during multiple CO2 sorption (60 °C) and regeneration (200 °C) tests due to the formation of the KAl(CO3)(OH)2 phase, which could be converted into the original K2CO3 phase above 300 °C. However, the new regenerable potassium-based sorbent (Re-KAl(I)) maintained its CO2 capture capacity during multiple tests even at a regeneration temperature of 130 °C. In particular, the CO2 capture capacity of the Re-KAl(I)60 sorbent which was prepared by the impregnation of Al2O3 with 60 wt.% K2CO3 was about 128 mg CO2/g sorbent. This excellent CO2 capture capacity and regeneration property were due to the characteristics of the Re-KAl(I) sorbent producing only a KHCO3 phase during CO2 sorption, unlike the KAlI30 sorbent which formed the KHCO3 and KAl(CO3)(OH)2 phases even at 60 °C. This result was explained through the structural effect of the support containing the KAl(CO3)(OH)2 phase which was prepared by impregnation of Al2O3 with K2CO3 in the presence of CO2. 相似文献
7.
This paper presents an experimental work that studies the performance of a counterflow cooling tower with expanded wire mesh packing. Due to complicated configuration of the expanded wire mesh packing surface, it is not possible to measure the temperature of the air in the intermediate section of the cooling tower, but only that of the exit air and water temperature. In the experimental study a new concept of psychrometric gun technique is used to measure dry/wet bulb temperature of air at intermediate points of tower packing. First, the paper elaborates on the effect of atmospheric conditions, water mass flow rate and inlet temperature on the variation of the thermodynamics properties of moist air inside the cooling tower and thermal performance characteristics. Second, exergy analysis is applied to study the cooling tower potential of performance using the psychrometric gun technique. An analytical model was compared with experimental data. 相似文献
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In digital mammography, the resulting electronic image is very large in size, which poses a significant challenge to the transmission, storage, and manipulation of images. Microcalcification is one of the earliest signs of breast cancer, and it tends to appear in small-sized, low-contrast radiopacities in the high-frequency spectrum of a mammographic image. Scalar wavelets excel multiwavelets in terms of peak-signal-to-noise ratio (PSNR), but fail to capture high-frequency information. This study proposes mammographic image compression and microcalcification detection in original and compressed reconstructed images using multiwavelets and neural networks. It also details the classification results obtained through the multiwavelet-based scheme in comparison with the existing scalar wavelet-based scheme. For a testing sample of 30 images, the proposed classification scheme outperforms the scalar wavelet-based classification by a sensitivity of 2.23% and specificity of 3.4% for original (uncompressed) images. Also, it increases the sensitivity by 2.72% and specificity by 8.4% for compressed reconstructed images. This increase in sensitivity and specificity demonstrates a better performance of the proposed detection scheme. 相似文献
10.
Ramkumar Ramakrishnan Ragupathy Arumugam 《Journal of Mechanical Science and Technology》2012,26(5):1643-1650
Optimization of cold water temperature in forced draft cooling tower with various operating parameters has been considered in the present work. In this study, response surface method (RSM) and an artificial neural network (ANN) were developed to predict cold water temperature in forced draft cooling tower. In the development of predictive models, water flow, air flow, water temperature and packing height were considered as model variables. For this propose, an experiment based on statistical five-level four factorial design of experiments method was carried out in the forced draft cooling tower. Based on statistical analysis, packing height, air flow and water flow were high significant effects on cold water temperature, with very low probability values (< 0.0001). The optimum operating parameters were predicted using RSM, ANN model and confirmed through experiments. The result demonstrated that minimum cold water temperature was optioned from the ANN model compared with RSM. 相似文献