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41.
The study of near-nanocrystalline cermet composite coating was performed by depositing near-nanocrystalline WC-17Co powder
using the high velocity oxy-fuel spraying technique. The WC-17Co powder consists of a core with an engineered near-nano-scale
WC dispersion with a mean grain size 427 nm. The powder particle contains 6 wt pct of the ductile phase Co matrix mixed into
the core to ensure that the reinforcing ceramic phase WC material is discontinuous to limit debridement during wear, while
the remainder of the binding phase (11 wt pct) is applied as a coating on the powder particle to improve the ductility. The
tribological properties of the coating, in terms of corrosion resistance, microhardness, and sliding abrasive wear, were studied
and compared with those of an industrially standard microcrystalline WC-10Co-4Cr coating with a WC mean grain size 3 μm. Results indicated that the WC-17Co coating had superior wear and corrosion resistance compared to the WC-10Co-4Cr coating.
The engineered WC-17Co powder with a duplex Co layer had prevented significant decarburization of the WC dispersion in the
coating, thereby reducing the intersplat microporosity necessary for initiating microgalvanic cells. The improved wear resistance
was attributed to the higher hardness value of the near-nanocrystalline WC-17Co coating. 相似文献
42.
Raja Fawad Zafar Michael B. C. Khoo Sajal Saha Zhi Lin Chong 《Quality and Reliability Engineering International》2021,37(6):2329-2333
The progressive mean (PM) statistic is based on a simple idea of accumulating information of each subgroup by calculating the average progressively. Its weighting structure is based on a subgroup number that changes arithmetically, which makes the PM chart unique and efficient compared with the existing classical memory control charts. In a recent article (see reference 1), it was claimed that the PM chart is a special case of the exponentially weighted moving average (EMWA) chart. In this article, it is shown that even though the PM statistic can be written in the form of an EWMA statistic, the variance of the PM statistic is different from that of the EWMA statistic. Consequently, the limits of the PM chart are different from that of the EWMA chart. Therefore, it is found that the PM chart is not a special case of the EWMA chart; hence, the claim in reference 1 is incorrect. Furthermore, it is pointed out in this paper that no adaptive property in the weighting parameter of the PM statistic exists, further contradicting the claim in reference 1. 相似文献
43.
An uninterrupted cold chain is a continual series of storage and distribution activities that maintain a specific temperature or temperature range. Cold chain solutions typically involve excessive packaging to ensure that the desired product temperature is maintained through the distribution process, thereby increasing the logistics‐related costs. There is a myriad of solutions available for shipping temperature‐sensitive products, including those constructed with a variety of packaging materials as well as refrigerants. Although static characteristics for thermally insulated packaging solutions such as the R‐values of package systems as well as the melting points and heat absorption rates of various refrigerants have been studied in the past, none of the past studies have evaluated the effect of comprehensive distribution on the reliability of the cold chain packaging solutions. This research was undertaken to study the temperature profiles for factors such as different densities for a given thickness of thermally insulating material, wall thicknesses and distribution environments for four different types of materials—polyurethane, virgin expanded polystyrene, recycled content expanded polystyrene and vacuum‐insulated panels. The temperature range of 2 °C–8 °C, critical for pharmaceutical drugs and vaccines, was targeted. An interesting regression‐based finding was that the interaction between the R‐value and the wall thickness significantly influenced the length of time the thermally insulated packages stayed in the desired range of 2 °C–8 °C . The findings of this study will be decisive in designing cost‐efficient and practical single‐use cold chain transportation solutions for temperature‐sensitive products. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
44.
Detection of cross-channel anomalies 总被引:1,自引:1,他引:0
Duc-Son Pham Budhaditya Saha Dinh Q. Phung Svetha Venkatesh 《Knowledge and Information Systems》2013,35(1):33-59
The data deluge has created a great challenge for data mining applications wherein the rare topics of interest are often buried in the flood of major headlines. We identify and formulate a novel problem: cross-channel anomaly detection from multiple data channels. Cross-channel anomalies are common among the individual channel anomalies and are often portent of significant events. Central to this new problem is a development of theoretical foundation and methodology. Using the spectral approach, we propose a two-stage detection method: anomaly detection at a single-channel level, followed by the detection of cross-channel anomalies from the amalgamation of single-channel anomalies. We also derive the extension of the proposed detection method to an online settings, which automatically adapts to changes in the data over time at low computational complexity using incremental algorithms. Our mathematical analysis shows that our method is likely to reduce the false alarm rate by establishing theoretical results on the reduction of an impurity index. We demonstrate our method in two applications: document understanding with multiple text corpora and detection of repeated anomalies in large-scale video surveillance. The experimental results consistently demonstrate the superior performance of our method compared with related state-of-art methods, including the one-class SVM and principal component pursuit. In addition, our framework can be deployed in a decentralized manner, lending itself for large-scale data stream analysis. 相似文献
45.
Sumit K. Mishra Nabanita Saha S. Singh Chhemendra Sharma M. V. S. N. Prasad Sachin Gautam Amit Misra Abhishek Gaur Deepika Bhattu Subhasish Ghosh Anubhav Dwivedi Rosalin Dalai Debajyoti Paul Tarun Gupta Sachchida N. Tripathi R. K. Kotnala 《Mapan》2017,32(3):229-241
Estimation of the direct radiative forcing (DRF) by atmospheric particles is uncertain to a large extent owing to uncertainties in their morphology (shape and size), mixing states, and chemical composition. A region-specific database of the aforementioned physico-chemical properties (at individual particle level) is necessary to improve numerically-estimated optical and radiative properties. Till date, there is no detailed observation of the above mentioned properties over Kanpur in the Indo-Gangetic Plain (IGP). To fill this gap, an experiment was carried out at Kanpur (IITK; 26.52°N, 80.23°E, 142 m msl), India from April to July, 2011. Particle types broadly classified as (a) Cu-rich particles mixed with carbon and sulphur (b) dust and clays mixed with carbonaceous species (c) Fe-rich particles mixed with carbon and sulfur and (d) calcite (CaCO3) particles aged with nitrate, were observed. The frequency distributions of aspect ratio (AR; indicator of extent of particle non-sphericity) of total 708 particles from April to June reveal that particles with aspect ratio range >1.2 to ≤1.4 were abundant throughout the experiment except during June when it was found to shift to high AR range, >1.4 to ≤1.6 (followed with another peak of AR i.e. >2 to ≤2.4) due to dust storm conditions enhancing the occurrence of more non-spherical particles over the sampling site. The spherical particles (and close to spherical shape; AR range, 1.0 to ≤1.2) were found to be <20% throughout the experiment with a minimum (11.5%) during June. Consideration of Homogeneous Equivalent Sphere Approximation (HESA) in the optical/radiative model over the study region is found to be irrelevant during the campaign. 相似文献
46.
N. Qureshi M.J. Bowman B.C. Saha R. Hector M.A. Berhow M.A. Cotta 《Food and Bioproducts Processing》2012,90(3):533-540
Studies were performed to identify chemical compounds present in wheat straw hydrolysate (WSH) that enhance acetone butanol ethanol (ABE) productivity. These compounds were identified as furfural and hydroxymethyl furfural (HMF). Control experiment resulted in the production of 21.38 g L?1 ABE with a productivity of 0.30 g L?1 h?1. WSH contained 0.04–0.34 g L?1 furfural and 0.12–0.88 g L?1 HMF. Addition of furfural to the fermentation medium at a concentration of 0.50 g L?1 resulted in a productivity of 0.88 g L?1 h?1 which is 293% of the productivity obtained in control experiments. Supplementation with 1.00 g L?1 HMF into the fermentation medium produced 25.27 g L?1 ABE with a productivity of 0.68 g L?1 h?1. A combination of furfural (0.50 g L?1) and HMF (0.50 g L?1) also enhanced ABE production and productivity when added to the fermentation medium. Both furfural and HMF enhanced specific productivity (233–308%) of ABE. In brief, WSH contained an adequate concentration of furfural and HMF that enhanced ABE productivity, specific productivity, and product concentration. 相似文献
47.
Sahan Trushad Wickramasooriya Kuruneru Suvash Chandra Saha YuanTong Gu 《传热工程》2017,38(11-12):1008-1017
ABSTRACTA novel and economical experimental technique has been developed to assess industrial aerosol deposition in various idealized porous channel configurations. This judicious examination of aerosol penetration in porous channels will assist engineers to better optimize designs for various engineering applications. Deposition patterns differ with porosity due to geometric configurations of the channel and superficial inlet velocities. Interestingly, it is found that two configurations of similar porosity exhibit significantly higher deposition fractions. Inertial impaction is profound at the leading edge of all obstacles, whereas particle buildup is observed at the trailing edge of the obstructions. A qualitative analysis shows that the numerical results are in good agreement with experimental results. 相似文献
48.
P. P. Bhattacharjee S. Saha J. R. Gatti 《Journal of Materials Engineering and Performance》2014,23(2):458-468
The effect of change in strain path during cold rolling on the evolution of microstructure and texture is investigated. For this purpose, high purity aluminum and Al-2.5%Mg alloy are deformed (~90% reduction in thickness) by unidirectional and cross cold rolling. Irrespective of the alloy system, copper-type texture is observed in unidirectional processed materials, while strong brass ({011}〈112〉) texture is developed during cross rolling. Unidirectionally rolled aluminum showed higher HAGB fraction, but similar HAGB spacing as compared to the cross-rolled aluminum after 90% reduction in thickness. At the same time, the internal misorientation in the cross-rolled 2N-Al is higher than in the unidirectionally rolled material. In contrast, Al-2.5% Mg alloy processed differently in both ways shows similar HAGB fraction, spacing, and internal misorientation distribution. These observations indicate that microstructure evolution due to strain path change is more strongly affected by dynamic recovery as compared to texture evolution. 相似文献
49.
50.
Subrata Mallick Satyanarayan Pattnaik Kalpana Swain Pintu K. De Arindam Saha Pushpen Mazumdar 《Drug development and industrial pharmacy》2013,39(7):726-734
This present study is a preliminary exploration of the affinity between a carboxylic model drug ibuprofen and aluminum hydroxide. Ibuprofen was comilled with aluminum hydroxide in different weight ratios in the solid state and was characterized by scanning electron microscopy (SEM), X-ray powder diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), and in vitro dissolution studies. XRD and SEM studies indicated complete interaction of ibuprofen with aluminum hydroxide and complete amorphization of aluminum hydroxide–ibuprofen complexed salt as well, on comilling with aluminum hydroxide at 1:2 ratio. FTIR data showed the disappearance of acid carbonyl peak with the appearance and the corresponding increase in absorbance of new signal at 1,682 cm?1 in the 1:1 and 1:2 ibuprofen–aluminum hydroxide-comilled powder. The accompanied increase in the absorbance of carboxylate peak in the ibuprofen–aluminum hydroxide physical mixture, and 1:0.1, 1:0.5, 1:1, and 1:2 (IBApm, and IB1A0.1, IB1A0.5, IB1A1, and IB1A2, respectively) comilled powder indicated an acid–base reaction between ibuprofen and aluminum hydroxide. On storage at 40°C and 75% relative humidity (RH) for 10 weeks, XRD study showed the absence of reversion to the crystalline state and FTIR data revealed continued increase of new signal at 1,682 cm?1 relative to carboxylic acid peak and no reappearance of carboxylic acid peak. In vitro dissolution studies revealed that the percent release of ibuprofen from the aluminum hydroxide-comilled powder is in the following order: IB1A2 < IB1A1 < ibuprofen crystal < ibuprofen milled alone < IB1A0.1 < IB1A0.5. Aluminum metal cation might have interacted to form a complex through the carboxyl and carbonyl groups of ibuprofen. Improved dissolution of drug associated with IB1A0.1 and IB1A0.5 is because of the absence of a new signal at 1,682 cm?1 and improved amorphization of the drug to some extent. Dissolution of drug affected in IB1A2 and IB1A1 may be because of the insoluble stable complex formation. 相似文献