The concentrations of different forms of Zn, Cu, Mn, Ni, Cd, Cr, Pb and Fe metals were determined for the roadside sludge collected from pickling-rolling and electroplating industrial area. In sludge ...the relative abundance of total heavy metals were Fe
>
Mn
>
Cr
>
Ni
>
Cu
>
Pb
>
Zn
>
Cd and DTPA-extractable metals were in the order -- Fe
>
Ni
>
Mn
>
Cr
>
Cu
>
Zn
>
Pb
>
Cd.
Pot-culture experiment was conducted in soils amended with sludge (0%, 10%, 20%, 30%), pretreated with lime (0%, 0.5% and 1%). The soils were alkaline in nature (pH
>
8.3) with organic carbon contents were 0.34% and 0.72%. The most abundant total and bio-available metal was Fe. Two wheat seedlings were grown in each pot containing 3
kg sludge-amended or control soil and the experiment was conducted till harvesting. Application of sludge increased both total and bio-available forms of metals in the soils, while lime application decreased the bioavailability of heavy metals in sludge-amended soils. The content of organic carbon showed positive correlation with all metals except Zn, Cr and Pb. CEC also showed a strong positive correlation (
R
2
>
0.7) with Fe, Mn, Cu, Ni and Cd. Though wheat plants are not accumulators, the translocation efficiency was appreciably high. The translocation factor from shoot to grain was found smaller than that of root to shoot of wheat plants. This makes an implication that the heavy metal accumulation was proportionally lesser in grain than in shoot. In, 10% sludge with 0.5% lime-amended soils; each of these toxic heavy metals was found to be within permissible range (USEPA). Hence, on the basis of present study, the best possible treatment may be recommended.
This research article explains the influence of magnetic field and volume fraction of carbon nanotubes (CNTs) on the flow over a stretching sheet in rotating frame. We analysed the behaviour of base ...fluid such as water with both kind of CNTs i.e. multi-wall carbon nanotubes (MWCNTs) and single-wall carbon nanotubes (SWCNTs). The nanofluid transport mechanism is obtained following Xue model. The mathematical model is developed by order of magnitude analysis. Governing partial differential equations are first converted into a system of ordinary differential equations making the use of suitable similarity transformation and then solved by fourth order finite difference scheme using Newton's linearization technique, which helps us to deal with the non-linear terms in a very smooth way. Numerical simulation for the fluid velocity and fluid temperature along with Nusselt number and skin friction coefficient are carried out for a set of values of different regulatory flow parameters that characterize the physics of the flow graphically. An outstanding correlation is perceived in tabular form of mesh density solutions of different length of domain obtained by fourth order finite difference scheme. The Biot number, Brinkmann number and applied magnetic field have vital effects on the thermal energy irreversibility in terms of Bejan number.
•MWCNT and SWCNT as nanoparticles with water as base fluid•Its behaviour over a stretching sheet is examined in non-Darcy porous medium.•Impact of viscous and Joule dissipations are presented under convective boundary condition.•Numerical simulation is performed implementing fourth order finite difference scheme.•A brief discussion about entropy generation is presented in terms of Bejan number.
The primary focus behind this research work is to unfold the heat and mass transfer characteristics of peristaltic transport of hydromagnetic couple stress fluid through a porous medium in an ...inclined channel of asymmetric kind. Consideration of both Dufour and Soret effects is one of the key factors of this investigation. Simultaneous convective conditions of mass and heat transfer are satisfied by the channel walls. Beneath the presumptions of small Reynolds number along with long wavelength, the governing two-dimensional coupled differential equations are simplified after incorporating dimensionless variables. To calculate the pressure difference, the technique of numerical integration has been employed. Graphical demonstrations for velocity, temperature, concentration profiles have been sketched out under the influence of pertinent flow parameters. Pumping characteristics and trapping phenomenon for some particular kind of waveshapes are also highlighted through contour plots. Noteworthy findings are that near the center of the channel the maximum value of the temperature is attained due to the intensification of heat generation parameter. Also, Dufour number tends to enhance the temperature of the fluid, whereas Soret effect results in a downfall in the concentration field. Heat and mass transfer Biot numbers lead to an elevation in the concentration and temperature profiles, respectively. It is also perceived that a reduction in concentration takes place due to the presence of destructive kind of chemical reaction while a reverse trend is being followed during a chemical reaction of constructive kind. Moreover, both the pressure gradient as well as pressure difference act as increasing functions of the angle of inclination of the channel. Additionally, the general propensity of couple stress fluid parameter is to diminish the volume of the trapped bolus.
With an objective to unfold the flow and heat transfer characteristics of carbon nanotubes between two stretchable coaxial rotating disks, the present investigation has been carried out. The behavior ...of single- and multi-walled carbon nanotubes (SWCNTs and MWCNTs) taking water as the base fluid is analyzed. To formulate the energy equation, we have incorporated Cattaneo–Christov heat flux model. Consideration of such kind of model accounts the contribution by thermal relaxation. von Karman transformation has been implemented in order to reconstruct the governing partial differential equations into a system of ordinary differential equations. Employing optimal homotopy analysis method series solutions are obtained. Error analysis has also been performed and presented in tabular form. The physical clarifications for the behavior of fluid velocity, temperature, skin friction coefficient and Nusselt number are well demonstrated with the help of graphs and contour plots. One of the major outcomes of the present study signifies that water-based SWCNTs have a tendency to cause less drag and higher rate of heat transfer as compared to water-based MWCNTs. This investigation finds numerous applications in different mechanisms of thermal conversion for nuclear propulsion and spacecraft.
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•BOC8A/NO -An efficient solvent medium for Sr2+ separation from acid medium.•Aliphatic NO diluents reported for the first time in hydrometallurgy.•Ion dissociation mechanism is ...operative for the Sr2+ extraction.•Recovery of Sr2+ from loaded BOC8A/NO phase by 0.01 M HNO3 solution.•DFT study supported expt. results of high affinity of diprotonated BOC8A for Sr2+.
In view of the limited solvent system known for the Sr2+ extraction from acidic media, extraction and recovery of 90Sr from acidic medium using novel Octabenzyloxyoctakis(N,N-diethylamino)carbonyl)methyloxycalix8arene (BOC8A) extractant in nitro alkane medium are presented in this paper. BOC8A and nitro alkanes have been synthesized and characterized by 1H NMR, 13C NMR, FTIR and GC–MS techniques. Solvent composition of 0.01 M BOC8A in nitro octane (NO) has been optimized for substantial amount of extraction of strontium from feed acidity of 3.5−4 M nitric acid, (D3.5−4 M HNO3 = 7.1–7.8). Poor extraction of Pu4+, Ba2+, Na+ and UO22+ and negligible extraction of Am3+, Cs+, Ru3+, Nd3+, Zr2+ and trivalent lanthanides are observed. Ion dissociation mechanism was found to be operative involving an extractable complex having Sr2+, BOC8A and HNO3 in a ratio of 1:1:2. About 99 % of Sr2+ from the loaded solvent was recovered with 0.01 M HNO3. DFT calculations were used to predict the structures of free, protonated BOC8A and its complex with Sr2+. DFT result showed reorientation in conformation of BOC8A due to protonation resulting in the Sr2+ extraction from acidic medium with significantly high interaction energy between Sr2+ and diprotonated form of BOC8A.
In this paper, we present the results of a morphological study of Equatorial Spread F (ESF) irregularities over Indian region based mainly on observations of (1) amplitude scintillations on GPS ...L‐band signal and Rate of TEC Index (ROTI) obtained using a network of GPS receivers and (2) amplitude scintillations on a VHF signal using spaced receivers at Tirunelveli, an equatorial station. Occurrence of both amplitude scintillations on the GPS L1 signal and occurrence of significant ROTI recorded at several stations has been investigated. The latitudinal extent of L‐band scintillations shows that their strength is weak over the dip equator but stronger over Equatorial Ionization Anomaly (EIA) region, preferentially during vernal equinox. We find an equinoctial asymmetry in both the occurrence of scintillations and ROTI wherein their occurrence is greater in the vernal equinox than in the autumn equinox. Attempts have been made to understand the asymmetry in latitudinal extent using maximum cross‐correlation (CI) of intensity fluctuations obtained from the VHF spaced receivers observations. The observations suggest that occurrence of CI less than 0.5 is more in the vernal equinox than in the autumn equinox suggesting that the maximum height of the Equatorial Plasma Bubbles (EPBs) during vernal equinox may be higher than that during autumn equinox. TIMED/GUVI retrieved peak electron density during the same period also indicates that background electron density is higher and more symmetric during vernal equinox than autumn equinox. Hence, our results suggest that background electron density may be playing a vital role in creating the equinoctial asymmetry.
Key Points
Occurrence of equinoctial asymmetry in the L‐band and VHF band signal
Height of the F layer is higher in the vernal equinox than autumn equinox
Background electron density is higher during vernal equinox than autumn equinox
The use of nanomaterials- and nanotechnology-based processes is growing at a tremendous rate in all fields of science and technology. Textile industry is also experiencing the benefits of ...nanotechnology in its diverse field of applications. Textile-based nanoproducts starting from nanocomposite fibers, nanofibers to intelligent high-performance polymeric nanocoatings are getting their way not only in high performance advanced applications but nanoparticles are also successfully being used in conventional textiles to impart new functionality and improved performance. Greater repeatability, reliability and robustness are the main advantages of nanotechnological advancements in textiles. Nanoparticle application during conventional textile processing techniques, such as finishing, coating and dyeing, enhances the product performance manifold and imparts hitherto unachieved functionality. New coating techniques like sol-gel, layer-by-layer, plasma polymerization etc. can develop multi-functionality, intelligence, excellent durability and weather resistance to fabrics. The present paper focuses on the development and potential applications of nanotechnology in developing multifunctional and smart nanocomposite fibers, nanofibers and other new finished and nanocoated textiles. The four main areas of textile chemical processing, namely nanofinishing, nanocoating, nanocomposite coating and nanodyeing, are covered in the first section of this paper and the second section deals with developments in nanocomposite fibers and nanofibers. The influence of nanomaterials in textile finishing and processing to enhance product performance is discussed. Nanocoating is a relatively new technique in the textile field and is currently under research and development. Polymeric nanocomposite coatings, where nanoparticles are dispersed in polymeric media and used for coating applications, are the most promising route to develop multifunctional and intelligent high-performance textiles. Not much research has been done on applying the concept of nanotechnology in dyeing of textiles except a few reports on dye particle size reduction, structural change in fibers or the surface etching of textiles to create nanostructured surfaces. The reduction in water consumption during nanotechnology applications in textile processing has the potential to control the effluent problems of a textile process house. The most researched area to produce multifunctional, smart fibers is the preparation of nanocomposite fibers where the exceptional properties of nanoparticles have been utilized to enhance and impart several functionalities on conventional textile grade fibers. Nanofibers are gaining popularity in some specialized technical applications such as filter fabric, antibacterial patches and chemical protective suits. Nanotechnological advances in these two areas of nanocomposite fibers and nanofibrous forms have also been reviewed.
Two types of Cs+ ion-selective crown ether–Nafion composite membranes have been prepared. In one case, the dibenzo-21-crown-7 (DB21C7) has been incorporated uniformly in the Cs+ form of Nafion-117 ...membrane in varying molar ratio with respect to Cs+, and in the other case, Cs+ driven loading of DB21C7 has been confined (ion gating) to a very small thickness (25 μm) from one of the surfaces of the Nafion-117 membrane. The surface confinement of Cs+ in the ion-gated membrane has been studied by energy dispersive X-ray spectroscopy and secondary ion mass spectrometry. The cation (Cs+/Na+) transport properties of the membranes have been studied under application of electric field. In the uniformly crown-ether-loaded membranes (Cs-Naf-CR), the decrease in crown ether molar ratio has been found to increase the mobility of Cs+ through the membrane at the cost of mutual cationic selectivity (Cs+ over Na+). On the other hand, enhanced selectivity of Cs+ over Na+ with significant cationic transport at room temperature has been obtained with the ion-gated membrane (Cs-H-Naf-CR). When applied to the simulated nuclear waste solution, selective transport of Cs+ has also been obtained using this gated membrane even in the presence of very high Na+ (Cs+:Na+ = 1:1428) concentration in aqueous solution.
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