Development of membranes by radiation grafting of acrylamide into polyethylene films: Properties and metal ion separation

Polyethylene‐g‐polyacrylamide membranes were prepared by graft polymerization of acrylamide into polyethylene films using a preirradiation technique. The membranes showed good swelling in water and a maximum of 232% swelling was achieved for a graft level of 590%. The electrical resistance of the membranes decreased with increase in the degree of grafting to 200% and then stabilized with a further increase in grafting to 590%. The membranes had an excellent binding capacity for mercury ions. Almost 99% mercury separation was achieved from a metal solution of 200 ppm. The metal binding capacity increased with increase in the degree of grafting in the membranes. A binding capacity as high as 6.2 mmol/g in a membrane with 590% grafting was achieved. The pH of the metal solution did not have any significant influence on the binding ability of the membranes. The mercury‐loaded membranes showed better thermal stability as compared to those without metal binding. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 282–291, 2002     

Nodal Point Relation for the Distribution of Sediments at Channel Bifurcation

This technical note explores the applicability of the general nodal point relation to describe the distribution of sediments at channel bifurcation. Experiments were conducted in a physical model of channel bifurcation to estimate the coefficient and exponent of the nodal point relation for different nose angles and upstream discharges. It was found that the nose angle is the major variable for the distribution of sediments to the downstream branches. The value of the exponent k found from experimental results was compared with that of a theoretical analysis. For a stable equilibrium, the value of k is greater than 5/3 from theoretical consideration when the Engelund–Hansen sediment transport formula is used. This was confirmed from the experimental results. This suggests that the distribution of sediments at channel bifurcation can be expressed by the general nodal point relation.     

Optimal Design of Remote Terminal Unit (RTU) for Wireless SCADA System for Energy Management

For energy deficit countries, the design of Supervisory Control and Data Acquisition (SCADA) based energy management systems for optimal distribution is of high interest. Such design involves development of Remote Terminal Unit (RTU) which is considered as an essential component of any high scale SCADA system and it is functioning as remote field data interface. Considering various generations of SCADA, two different designs of an RTU are proposed for third generation (Networked Approach) SCADA in view of energy management applications. One design includes Programmable Logic Controller (PLC) as CPU of RTU and other would involve Field Programmable Gate Array (FPGA) instead of PLC. This paper results in comparative study of two different selections of CPUs for designing an RTU based on performance measurement. PLC based RTU exhibits limited features where as FPGA based RTU possesses unique features like encryption support, radio support and large memory area. Suitable simulation tools are needed in order to determine the best approach. The main objective of this study is to propose a design outline considering significant parameters that facilitates optimized development and low cost implementation of an RTU, also featured with wireless communication. In addition to the optimized design of an RTU by means of comparative study, a brief discussion on optimization of wireless link for Remote Terminal Unit is also presented. This phase involves detailed comparison among various options considering the RF spectrum for optimal solution. This segment of research results in design of optimized wireless link for the planned low cost Remote Terminal Unit (RTU). A scenario depicting multiple RTUs communicating with one Tele-Control Interface (TCI) is discussed to address optimized implementation of wireless SCADA.     

Synthesis,characterization, and thermal and antimicrobial studies of newly developed transition metal–polychelates derived from polymeric Schiff base

Monomeric Schiff base derived from salicylaldehyde and 1,3‐diaminopropane was subjected to polycondensation reaction with formaldehyde and piperazine in basic medium. The resin was found to form polychelates readily with Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) metal ions. The materials were characterized by elemental analysis, spectral studies (IR, ¹H‐NMR, ¹³C‐NMR, and UV–visible), magnetic moment measurements, and thermal analysis. The electronic spectra and magnetic moment measurements of the synthesized polychelates confirmed the geometry of the central metal ion. Metal–resin bonds were registered in the IR spectra of the polychelates. The thermogravimetric analysis data indicated that the polychelates were more stable than the corresponding polymeric Schiff base. All the synthesized metal–polychelates showed excellent antibacterial activities against the selected bacteria. The antimicrobial activities were determined by using the shaking flask method, where 25 mg/mL concentrations of each compound were tested against 10⁵ CFU/mL bacteria solutions. The number of viable bacteria was calculated by using the spread‐plate method, where 100 μL of the incubated antimicrobial agent in bacteria solutions were spread on agar plates, and the number of bacteria was counted after 24 h of incubation period at 37°C. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009