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91.
Formation and Stability of Equiatomic and Nonequiatomic Nanocrystalline CuNiCoZnAlTi High-Entropy Alloys by Mechanical Alloying 总被引:1,自引:0,他引:1
Varalakshmi S. Kamaraj M. Murty B.S. 《Metallurgical and Materials Transactions A》2010,41(10):2703-2709
Nanocrystalline equiatomic high-entropy alloys (HEAs) have been synthesized by mechanical alloying in the Cu-Ni-Co-Zn-Al-Ti
system from the binary CuNi alloy to the hexanary CuNiCoZnAlTi alloy. An attempt also has been made to find the influence
of nonequiatomic compositions on the HEA formation by varying the Cu content up to 50 at. pct (Cu
x
NiCoZnAlTi; x = 0, 8.33, 33.33, 49.98 at. pct). The phase formation and stability of mechanically alloyed powder at an elevated temperature
(1073 K [800 °C] for 1 hour) were studied. The nanocrystalline equiatomic Cu-Ni-Co-Zn-Al-Ti alloys have a face-centered cubic
(fcc) structure up to quinary compositions and have a body-centered cubic (bcc) structure in a hexanary alloy. In nonequiatomic
alloys, bcc is the dominating phase in the alloys containing 0 and 8.33 at. pct of Cu, and the fcc phase was observed in alloys
with 33.33 and 49.98 at. pct of Cu. The Vicker’s bulk hardness and compressive strength of the equiatomic nanocrystalline
hexanary CuNiCoZnAlTi HEA after hot isostatic pressing is 8.79 GPa, and the compressive strength is 2.76 GPa. The hardness
of these HEAs is higher than most commercial hard facing alloys (e.g., Stellite, which is 4.94 GPa). 相似文献
92.
Investigating a New Approach to Film Casting for Enhanced Drug Content Uniformity in Polymeric Films
V. A. Perumal D. Lutchman I. Mackraj 《Drug development and industrial pharmacy》2013,39(10):1036-1047
Films prepared by conventional casting onto trays such as teflon-coated perspex trays (TCPTs) suffer from poor drug content uniformity. The aim of this study was to prepare a silicone-molded tray (SMT) with individual wells for film casting and to evaluate it in terms of enhancing drug content uniformity. Films were prepared by solvent evaporation or emulsification and cast onto TCPT and SMT. Preparation of films by the SMT method was superior in terms of meeting drug content uniformity requirements. As compared with the TCPT method, the SMT casting method also reduced the variability in mucoadhesivity, drug release, and film thickness. Reproducibility of the SMT method was demonstrated in terms of drug content, mucoadhesion, and drug release. 相似文献
93.
Rengasamy Ragupathi Raja Kannan Radjassegarin Arumugam Palanisamy Iyapparaj Thirunavukarasu Thangaradjou Perumal Anantharaman 《Food chemistry》2013,136(3-4):1484-1489
It is essential to study the phytochemical constituents and toxicological properties of seagrasses when considering their food applications. Aqueous methanolic extracts of six seagrasses were evaluated for their antibacterial, cytotoxic (brine shrimp leathality assay) and haemolytic activity. Thin layer chromatography (TLC) and phytochemical analysis were used to compare the phytochemical profiles of six seagrasses. Among the six seagrasses examined, Halodule pinifolia and Cymodocea rotundata showed predominant growth inhibitory activity against all the tested human pathogens. Cytotoxicity of seagrass extracts against nauplii of Artemia salina revealed that Syringodium isoetifolium exhibited lesser toxicity with LC50 value of 699.096 μg/ml. Of all the seagrasses tested, H. pinifolia recorded the minimum haemolytic activity of 2.07 ± 0.63% at 1000 μg/ml concentration. Phytochemical analysis showed the presence of common plant chemical constituents which varied with respect to species. The present findings suggest the possible pharmacological applications of selected seagrasses that can be used as food ingredients. 相似文献
94.
95.
R.K. Bhuyan T. Santhosh Kumar D. Goswami A.R. James A. Perumal D. Pamu 《Materials Science and Engineering: B》2013,178(7):471-476
We report the study of the effects of processing parameters and additive concentration on the structure, microstructure and microwave dielectric properties of MTO–CeO2 (x wt.%) ceramics with x = 0, 0.5, 1.0 and 1.5 prepared by solid-state reaction method by adding CeO2 nanoparticles as a sintering aid. The pure Mg2TiO4 ceramics were not densifiable below 1450 °C. However, when CeO2 nanoparticles were added to MTO, the densification achieved at 1300 °C along with the increase in average grain size with the uniform microstructure and improved microwave dielectric properties. This is mainly driven by the large surface energy of CeO2 nanoparticles and their defect energy during the sintering process. While the addition of CeO2 nanoparticles in MTO ceramics does not change the dielectric constant (?r), the unloaded quality factor (Qu) was altered significantly. MTO–CeO2 (1.5 wt.%) ceramics sintered at 1300 °C exhibit superior microwave dielectric properties (?r ~ 14.6, Q × f0 ~ 167 THz), as compared to the pure Mg2TiO4 ceramics. The observed results are correlated to the enhancement in density and the development of uniform microstructure with the enhanced grain size. 相似文献
96.
Mrinmoy Ghosh Krishna Kanth Pulicherla Venkata Perumal Babu Rekha Adapa Vijayanand Krothapalli Raja Surya Sambasiva Rao 《International Journal of Dairy Technology》2013,66(2):256-263
The present study was conducted to analyse the physiochemical properties of Indian paneer whey. High concentration of minerals such as potassium, calcium, zinc and sodium, as NaCl, were observed which indicates the suitability of paneer whey in the preparation of beverages. A central composite rotatable design (CCRD) of response surface methodology (RSM) was employed to optimise the hydrolysis of lactose from whey using cold‐active β‐galactosidase of Thalassospira frigidphilosprofundus. Results indicated that 80% of lactose was hydrolysed at pH of 6.5 at 20 °C in 40 min in comparison with 40% at 30 °C. This emphasises the potential use of cold‐active β‐galactosidase in dairy industry. 相似文献
97.
Maheswari Ramasamy Velayutham Subburaj Perumal Vigneshwaran Basharan Willjuice Iruthayarajan Maria Silluvairaj 《电力部件与系统》2014,42(14):1611-1622
Abstract—Partial discharge (PD) measurement has emerged as a dominant investigative tool for condition monitoring of insulation in high voltage equipment. In general, PD signals are severely polluted by several noises like white noise, random noise, discrete spectral interferences (DSI). The challenge lies with removing these noises from PD signal effectively by preserving the signal features. In this article, support vector machine (SVM) based denoising technique has been proposed for the removal of white noise from PD signal. The proposed SVM technique retains the edge of the original signal efficiently and also pseudo Gibbs phenomenon does not exist with SVM technique. In order to evaluate the effectiveness of the proposed method, artificially simulated PD signal mixed with white noise and the measured PD readings are considered. For the purpose of comparison, other denoising techniques such as fast Fourier transform (FFT), discrete wavelet transform (DWT), and translation invariant wavelet transform (TIWT) are also considered. The results reveal that, SVM based denoising technique shows better performance in terms of higher signal to noise ratio, signal reconstruction error ratio, cross correlation coefficient and reduction in noise level, mean square error, and waveform distortion. 相似文献
98.
Nataraj Loganayaki Perumal Siddhuraju Sellamuthu Manian 《Food science and biotechnology》2010,19(1):121-127
In the present study, chloroform, acetone, and methanol extracts of Solanum torvum and Solanum nigrum leaves and fruit were evaluated for their in vitro antioxidant activity using ferric reducing antioxidant power, 2,2-diphenyl-1-picryl-hydrazyl (DPPH), ABTS·+, iron chelation, and antihemolytic activity. Among the various solvents used, the maximum yield was obtained in chloroform
followed by acetone and methanol. The total phenolics were also significantly higher in the chloroform extracts and the in vitro antioxidant activity was shown to be highly dependant on the total phenolic content (p<0.01). The DPPH· and 2,2′azinobis(3-ethylbenzothiozoline-6-sulfonic acid) diammonium salt (ABTS) cation radical scavenging activities were
well proved with the ferric reducing antioxidant capacity of the extracts. The potential of multiple antioxidant activity
of samples can be further evidenced by inhibition of reactive oxygen mediated erythrocyte cell lysis and metal ion chelating
activity. In conclusion, the results presented here implied leaves and fruits of S. torvum and S. nigrum could be considered as health supplements and nutraceuticals/functional foods. 相似文献
99.
Kandhasamy Sowndhararajan Perumal Siddhuraju Sellamuthu Manian 《Food science and biotechnology》2010,19(2):503-509
Antioxidant potential and total phenolics content of 70% acetone extracts of the raw and processed seeds of Bauhinia vahlii were evaluated. The extract of raw seeds contained higher levels of total phenolics (30.8 g/100 g) and tannins (19.6 g/100
g) compared to dry heated and soaking followed by autoclaving seed extracts. Extracts were screened for antioxidant and free
radical scavenging activities using various chemical and in vitro model systems. In all the models, except DPPH radical scavenging activity, the extract from raw seeds manifested the strongest
antioxidant activity than that from processed seeds. In β-carotene/linoleic acid emulsion system and superoxide scavenging
activity, the raw seed extract registered more activity when compared to the standards (butylated hydroxyanisole and α-tocopherol).
Whereas, the extract from dry heated seed exhibited higher DPPH· scavenging activity (IC50 70.77 μg/mL) than the raw seeds (IC50 74.4 μg/mL). This study has to some extent validated the antioxidant potential of the seeds of B. vahlii. 相似文献
100.
Thinagaran Perumal Abd Rahman Ramli Chui Yew Leong Khairulmizam Samsudin Shattri Mansor 《Automation in Construction》2010,19(2):160-168
Managing heterogeneous subsystems in an intelligent building has always been elusive due to lack of interoperability factor. This is due to the nature of heterogeneous systems in an intelligent building as a distributed entity that needs a certain degree of interoperability and joint execution of tasks for managing heterogeneous systems that consist of different platforms and protocols. There is a need for interoperability in an intelligent building with a bespoke solution that could make the heterogeneous subsystems ‘talk’ with each other and interoperate regardless of the operating platform. To solve the interoperability problem, Web Services technology is seen as a potential solution that could deal with the dynamic environment of an intelligent building. In this paper, we describe a SOAP-based middleware implementation for managing heterogeneous subsystems in an intelligent building. The proposed middleware solution utilizes the SOAP technology together with ECA rule mechanism in managing subsystems interoperation in a federated manner. Experiments and performance evaluation of the middleware had been carried out to justify the performance requirement of heterogeneous systems in an intelligent building. 相似文献