Removal of cationic pollutants from water by xanthated corn cob: optimization, kinetics, thermodynamics, and prediction of purification process

The removal of Cr(III) ions and methylene blue (MB) from aqueous solutions by xanthated corn cob (xCC) in batch conditions was investigated. The sorption capacity of xCC strongly depended of the pH, and increase when the pH rises. The kinetics was well fitted by pseudo-second order and Chrastil’s model. Sorption of Cr(III) ions and MB on xCC was rapid during the first 20 min of contact time and, thereafter, the biosorption rate decrease gradually until reaching equilibrium. The maximum sorption capacity of 17.13 and 83.89 mg g-1 for Cr(III) ions and MB, respectively was obtained at 40 °C, pH 5 and sorbent dose 4 g dm-3 for removal of Cr(III) ions and 1 g dm-3 for removal of MB. The prediction of purification process was successfully carried out and the verification of theoretically calculated amounts of sorbent was confirmed by using packed-bed column laboratory system with recirculation of the aqueous phase. The wastewater from chrome plating industry was successfully purified, i.e. after 40 min concentration of Cr(III) ions was decreased lower than 0.1 mg dm-3. Also, removal of MB from the river water was successfully carried out and after 40 min removal efficiency was about 94 %

Evaluation of lymph node numbers for adequate staging of Stage II and III colon cancer

<p>Abstract</p> <p>Background</p> <p>Although evaluation of at least 12 lymph nodes (LNs) is recommended as the minimum number of nodes required for accurate staging of colon cancer patients, there is disagreement on what constitutes an adequate identification of such LNs.</p> <p>Methods</p> <p>To evaluate the minimum number of LNs for adequate staging of Stage II and III colon cancer, 490 patients were categorized into groups based on 1-6, 7-11, 12-19, and ≥ 20 LNs collected.</p> <p>Results</p> <p>For patients with Stage II or III disease, examination of 12 LNs was not significantly associated with recurrence or mortality. For Stage II (HR = 0.33; 95% CI, 0.12-0.91), but not for Stage III patients (HR = 1.59; 95% CI, 0.54-4.64), examination of ≥20 LNs was associated with a reduced risk of recurrence within 2 years. However, examination of ≥20 LNs had a 55% (Stage II, HR = 0.45; 95% CI, 0.23-0.87) and a 31% (Stage III, HR = 0.69; 95% CI, 0.38-1.26) decreased risk of mortality, respectively. For each six additional LNs examined from Stage III patients, there was a 19% increased probability of finding a positive LN (parameter estimate = 0.18510, p < 0.0001). For Stage II and III colon cancers, there was improved survival and a decreased risk of recurrence with an increased number of LNs examined, regardless of the cutoff-points. Examination of ≥7 or ≥12 LNs had similar outcomes, but there were significant outcome benefits at the ≥20 cutoff-point only for Stage II patients. For Stage III patients, examination of 6 additional LNs detected one additional positive LN.</p> <p>Conclusions</p> <p>Thus, the 12 LN cut-off point cannot be supported as requisite in determining adequate staging of colon cancer based on current data. However, a minimum of 6 LNs should be examined for adequate staging of Stage II and III colon cancer patients.</p

Directly patterned substrate-free plasmonic 'nanograter' structures with unusual Fano resonances

The application of three-dimensional (3D) plasmonic nanostructures as metamaterials,nano-antennas, and other devices faces challenges in producing metallic nanostructures with easily definable orientations, sophisticated shapes and smooth surfaces that are operational in the optical regime and beyond. Here, we demonstrate that complex 3D nanostructures can be readily achieved with focused-ion-beam irradiation-induced folding and examine the optical characteristics of plasmonic “nanograter” structures that are composed of free-standing Au films.These 3D nanostructures exhibit interesting 3D hybridization in current flows and exhibit unusual and well-scalable Fano resonances at wavelengths ranging from 1.6 to 6.4 μm. Upon the introduction of liquids of various refractive indices to the structures, a strong dependence of the Fano resonance is observed, with spectral sensitivities of 1400 nm and 2,040 nm per refractive-index-unit (RIU) under figures of merit of 35.0 and 12.5, respectively, for low-order and high-order resonance in the near-infrared region. This work indicates the exciting, increasing relevance of similarly constructed 3D free standing nanostructures in the research and development of photonics and metamaterials

Non-intrusive dynamic measurements of nanofluid-based heat transfer phenomena under thermally developing flow regime in the context of compact channels

Laser interferometry-based forced convective heat transfer experiments in the context of compact channels using nanofluids are reported. Experiments have been carried out under thermally-developing flow conditions for a range of Reynolds numbers. De-ionized water and alumina/water-based dilute nanofluids have been employed as the coolant medium. The nanofluid-based experiments employ three volumetric concentrations of 0.01%, 0.03% and 0.05%. Projection data of the convective fields have been recorded using a Mach-Zehnder interferometer. Phenomena such as thermal boundary layer profiles and thickness of thermal boundary layer have been interpreted based on the infinite fringe setting mode of the interferometer, while the quantitative information in the form of whole-field temperature distributions and heat transfer coefficients have been retrieved from the wedge fringe setting. Effects of increasing Reynolds numbers and volumetric concentrations of nanofluids on thermal boundary layer profiles and the resultant heat transfer rates have been investigated. Results of the experiments carried out at low Reynolds number (Re < 513) reveal that the thermal boundary layer profiles are nearly insensitive to the changes in the concentrations of dilute nanofluids, while a significant enhancement in the heat transfer coefficient is seen as the concentrations of nanofluid is increased. On other hand, at higher Reynolds numbers, increasing concentrations of dilute nanofluids leads to a considerable increase in the thickness of thermal boundary layer that is accompanied with a mild deterioration in the heat transfer rates. Based on the primary findings of the experiments, that are purely non-intrusive in nature, various plausible mechanisms that govern the heat transfer characteristics of dilute nanofluids have been discussed. (C) 2016 Elsevier Inc. All rights reserved

Interferometric study of heat transfer characteristics of Al2O3 and SiO2-based dilute nanofluids under simultaneously developing flow regime in compact channels

Performance evaluation of two types of nanofluids in influencing the heat transfer phenomena in the context of compact channels has been presented. Experiments have been conducted in forced convection regime for a range of Reynolds numbers. Three different types of coolant fluids i.e. de-ionized water (base fluid), Al2O3 and SiO2-based dilute nanofluids with volumetric concentrations of 0.005%, 0.01% and 0.02% have been employed. A Mach-Zehnder interferometer has been used for recording the real time projection data of the convective field. The interferometer has been operated in infinite as well as wedge fringe setting mode. The infinite fringe setting images have been employed for discussing the effect of nanoparticles on phenomena like thermal boundary layer profiles, changes in the thickness of thermal boundary layers, etc. The wedge interferograms have been employed for quantitative analysis. A direct comparison of heat transfer characteristics of Al2O3 and SiO2 nanoparticles has been presented on the basis of their relative influence on the thickness of thermal boundary layers, temperature gradients and the resultant heat transfer rates. The results of the study clearly reveal the effectiveness and higher heat transfer characteristics of Al2O3 nanoparticles than that of SiO2. It is seen that the Al2O3 nanoparticles have greater ability in disrupting the thermal boundary layer profiles and lead to higher percentage reduction in the thickness of thermal boundary layers. The resultant heat transfer coefficients with Al2O3-based dilute nanofluids have been found to be significantly higher than the base fluid and the SiO2-based nanofluids for any given volumetric concentration. It is experimentally demonstrated that the phenomena like increased thermal conductivity, boundary layer disruptions and advection effects primarily control the heat transfer rates in the lower range of Reynolds numbers (Re < 500) while at higher Reynolds numbers, it is mainly the advection effects that influence the heat transfer coefficients in the range of volume concentrations of dilute nanofluids employed in the experiments. (C) 2015 Elsevier Ltd. All rights reserved