Processing of carbon-fiber reinforced (SiC + ZrC) mini-composites by soft-solution approach and their characterization

Carbon-fiber reinforced (SiC + ZrC) mini-composites have been prepared via soft-solution process using inorganic precursors. In this process, water-soluble compounds have been used to act as precursor materials to impregnate the fiber tow. Thermal analysis provided the temperature range for the pyrolysis to convert the precursors into the desired (SiC + ZrC) matrix. X-ray diffraction of the composites confirmed the phase formation and the crystallite size of these phases were in the range of 25–40 nm. Cross-sectional microstructures of the composites have shown the matrix formation around each individual fiber. The mechanical properties revealed that the tensile strength and fracture energy of the composites pyrolyzed at 1600 °C were significantly higher with typical composite failure behavior, as compared to those pyrolyzed at 1700 °C. The statistical size effects of the tensile strength were investigated on the basis of the Weibull statistics.     

Synthesis,microstructure and electrical conductivity of carbon nanotube–alumina nanocomposites

Carbon nanotube–alumina (CNT–Al₂O₃) nanocomposites have been synthesized by direct growth of carbon nanotubes on alumina by chemical vapor deposition (CVD) and the as-grown nanocomposites were densified by spark plasma sintering (SPS). Surface morphology analysis shows that the CNTs and CNT bundles are very well distributed between the matrix grains creating a web of CNTs as a consequence of their in situ synthesis. Even after the SPS treatment, the CNTs in the composite material are still intact. Experimental result shows that the electrical conductivity of the composites increases with the CNT content and falls in the range of the conductivity of semiconductors. The nanocomposite with highest CNT content has electrical conductivity of 3336 S/m at near room temperature, which is about 13 orders of magnitude increase over that of pure alumina.     

Mass propagation and essential oil analysis of Artemisia vulgaris

Artemisia vulgaris L. (Mugwort) is a threatened and valuable medicinal plant. Attempts have been made in this research to mass propagate its plantlets through in vitro liquid culture technology using Murashige and Skoog (MS) basal medium supplemented with 6-benzyl adenine (BA) (0.44-8.88 microM). Initially, 22.6 shoots (99.9% shooting frequency) developed from shoot tip explants cultured in MS with 4.44 microM BA at 100 ml flask capacity. This was further subcultured at increasing flask capacity (150, 250, and 500 ml) for shoot proliferation. Of the different concentrations of BA and flask capacities tested, 4.44 microM BA and 500 ml flask capacity were found to produce a maximum of 85.5 shoots after 30 d of culture. Shoot proliferation was found to increase with increasing flask capacity whereas shoot number decreased with increasing BA concentration (>4.44 microM). Individual shoots were isolated and rooted on MS medium containing 8.56 microM indole-3-acetic acid (IAA). Then the plantlets were acclimatized under standard laboratory conditions and later under greenhouse conditions. Fresh leaves were collected from greenhouse-grown plants and subjected to essential oil analysis by the simultaneous distillation and extraction method. GC-MS results revealed the presence of 88 components and the extracted oil was rich in camphor (16.8%), alpha-thujone (11.3%), germacrene D (7.2%), camphene (6.5%), 1,8-cineole (5.8%) and beta-caryophyllene (5.4%). This in vitro strategy can be a reliable method for the steady production of a large number of plants for essential oil production, which is reported for the first time for A. vulgaris.     

Taxonomic importance of spore morphology in Thelypteridaceae from Northern Pakistan

Spore morphology of Thelypteridaceae species growing in Malakand Division, Northern Pakistan, was studied using both light microscopy and scanning electron microscopy. The taxa are Christella dentata and Glaphyropteridopsis erubescens in the subfamily Thelypteridoideae, and Phegopteris connectilis, Pseudophegopteris pyrrhorhachis, and Pseudophegopteris levingei in the subfamily Phegopteridoideae. The studied species exhibit differences in spore size, exospore thickness, color, and ornamentation. Spores of the studied species are monolete and medium‐sized, and shape is ellipsoidal in both polar and equatorial views. The average measurement of the polar diameter ranges from 27 μm to 31 μm, whereas in the equatorial direction it varied from 20 μm to 40 μm. The exospore thickness ranges from 1.2 μm to 2.4 μm. Reticulate, laevigate with microgranules, cristate, and coarsely echinate surface ornamentation are observed among the species. Multivariate analysis including unweighted pair group method with arithmetic mean and principal component analysis was used for the grouping and discrimination of species and genera.     

Solar map of India under clear sky conditions

This paper focusses on generation of solar irradiation map under clear sky conditions using r.sun model. Direct Irradiation, diffuse irradiation and global irradiation maps are plotted using programme which was developed in C language. This programme calculates different components of solar irradiation using clear sky model (r.sun). Further Surfer software was used to plot different irradiation maps. All three values (Direct Irradiation, Global Irradiation and Diffuse Irradiation) were compared by IMD values for performing statistical analysis i.e. Mean Bias Error (MBE), Root Mean Square Error (RMSE) and standard deviation. MBE was found within ±10%, RMSE lies within <20% and standard deviation was found to have very low value which indicated good fitting between model results and calculated values. Therefore the r.sun model is good model and can be used for computing solar irradiation for India.     

Electrochemical behavior of nanostructured graphene nickel phosphorus composite coating on copper

Journal of Applied Electrochemistry - The present work is focused on the effects of graphene addition on the electrochemical performance of environmentally benign nanostructured...     

Effects of baking conditions on colour,texture and crumb grain characteristics of Chhana Podo

Baking, the key step in the preparation of Chhana Podo, involves simultaneous heat and mass transfer that induces physicochemical and structural changes in the product. The effects of baking conditions on colour, texture and crumb grain development in the product were evaluated. The browning index of baked Podo increased from the initial value of 15.7 to 95, 101 and 112, at baking temperatures of 120, 135 and 150 °C, respectively. Browning kinetics followed the logistic model (R² > 0.98) with an activation energy of 17.81 kJ/mol. In general, crumb grain characteristics such as mean cell area, cell density and cell‐to‐total area ratio increased with increase in baking time and temperature. Textural attributes such as hardness, chewiness and gumminess increased with baking time and temperature while springiness, cohesiveness and resilience increased up to 40 min due to the filling‐up of pores water and liquid by fat and expanding water, but decreased thereafter.     

A data constrained approach for brain tumour detection using fused deep features and SVM

Multimedia Tools and Applications - The identification of MR images of the brain with tumours is one of the most critical tasks of any brain tumour (BT) detection system. Interestingly, because of...     

Performance comparison between Chaos and quantum-chaos based image encryption techniques

Multimedia Tools and Applications - Today’s digital era has undertaken most of the responsibilities of public and private sectors, not only the industries or big organizations dependent on...     

Double Stage Gaussian Filter for Better Underwater Image Enhancement

Wireless Personal Communications - Major issue in marine environment imaging is the expulsion of hazy scenes caused by natural phenomena such as absorption and scattering in underwater images. The...