Melamine‐based microporous polymer for highly efficient removal of copper(II) from aqueous solution

In this study, we investigated the ability of a melamine‐based microporous polymer network as an adsorbent for removal of copper(II) species from aqueous solutions. A designed Schiff based network (SNW) with high specific surface area was synthesized using melamine and terephthalaldehyde monomers at 180 °C for 3 days followed by a freeze‐drying process. The porous structure of the material was confirmed by SEM analysis and CO₂ adsorption/desorption studies at 77.3 K. The adsorption character of the SNW polymer for various metal salts, namely Pb(II), Fe(II), Hg(II), Zn(II), Ni(II) and Cd(II), was investigated and a specific sorption behaviour against Cu(II) salts was observed. The role of pH and contact time was examined and the highest adsorption capacity for Cu(II) was found as 92% with pH 3.5 at the end of 300 min. As evidenced by XRD and Fourier transform infrared spectral analysis, the sorption mechanism is attributed to the coordination system formed between amino groups in the porous structure and Cu(II) ions. Reusability of the system was also demonstrated by applying four cycles without any significant loss of activity. © 2016 Society of Chemical Industry     

Effect of Various Electrolytes on the Phase Separation and Thermodynamic Properties of p-Tert-Alkylphenoxy Poly (Oxyethylene) Ether in the Absence/Presence of Drugs

Cloud point (CP) measurements of 4-(1,1,3,3-tetramethylbutyl) phenyl-polyethyleneglycol (Triton X-100 (TX-100)) were performed in aqueous solution in the presence of drug Amikacin sulfate (AS)/Neomycin sulfate (NS)/(AS/NS+ different inorganic salts). In aqueous solution, the CP values of TX-100 first decrease with increasing concentration and then increase with increasing surfactant concentration. The CP values of TX-100 solutions were found to increase with the increasing concentration of the AS/NS drug. The CP values of TX-100-AS/NS mixtures were also observed to decrease with the increase of the concentration of salt. Different thermodynamic parameters such as standard free energy (), standard enthalpy () as well as the standard entropy () change of phase separation were calculated and discussed in relation to molecular interactions.     

Feasibility study of cogeneration in a plywood industry with power export to grid

Cogeneration is proved to be one of the promising energy management techniques, which offers an efficient method of producing electricity and useful thermal energy from a common source. In the present study various cogeneration options for a plywood industry in south India with power export is analyzed. It is found that the industry has a good potential for cogeneration. Three schemes such as steam turbine gas turbine and combined cycle are evaluated on the basis of Annualized Life Cycle Cost (ALCC). The steam turbine based cogeneration is found to be the best option as it has the least ALCC. The comparison was based on lean gas as fuel but the industry can save the fuel cost by utilizing the waste wood available which enhances the scope and economic feasibility of cogeneration. It is found that the proposed scheme can provide a tremendous saving in the annual operating cost compared to the existing facility with a payback period of 2.6 years.     

On the organization of human T-cell receptor loci: log-periodic distribution of T-cell receptor gene segments

The human T-cell repertoire is complex and is generated by the rearrangement of variable (V), diversity (D) and joining (J) segments on the T-cell receptor (TCR) loci. The T-cell repertoire demonstrates self-similarity in terms clonal frequencies when defined by V, D and J gene segment usage; therefore to determine whether the structural ordering of these gene segments on the TCR loci contributes to the observed clonal frequencies, the TCR loci were examined for self-similarity and periodicity in terms of gene segment organization. Logarithmic transformation of numeric sequence order demonstrated that the V and J gene segments for both T-cell receptor α (TRA) and β (TRB) loci are arranged in a self-similar manner when the spacing between the adjacent segments was considered as a function of the size of the neighbouring gene segment, with an average fractal dimension of approximately 1.5. Accounting for the gene segments occurring on helical DNA molecules with a logarithmic distribution, sine and cosine functions of the log-transformed angular coordinates of the start and stop nucleotides of successive TCR gene segments showed an ordered progression from the 5′ to the 3′ end of the locus, supporting a log-periodic organization. T-cell clonal frequency estimates, based on V and J segment usage, from normal stem cell donors were plotted against the V and J segment on TRB locus and demonstrated a periodic distribution. We hypothesize that this quasi-periodic variation in gene-segment representation in the T-cell clonal repertoire may be influenced by the location of the gene segments on the periodic-logarithmically scaled TCR loci. Interactions between the two strands of DNA in the double helix may influence the probability of gene segment usage by means of either constructive or destructive interference resulting from the superposition of the two helices.