Post-synthetic modification of conjugated microporous polymers

Control over the surface functionality and microporosity in conjugated microporous polymers (CMPs) has been achieved by the post-synthetic modification of amines into amides of with different alkyl chains, one of which was chiral. The surface areas, pore volumes, carbon dioxide uptakes and isosteric heat of adsorption for carbon dioxide can be rationally tuned.     

Robotic system for underwater inspection of bridge piers

The research objective is to develop an automated robotic system that will enable safe and cost-effective underwater inspection of bridge substructures. The system concept being developed is a semiautonomous robotic system that can carry a sensor platform underwater to detect scour, deterioration, or damage to support columns. It provides positional data and sensor information (video images) to the system operator; these can be verbally annotated while being recorded. The operator initiates basic commands and transmits them to the underwater apparatus. On-board microprocessor-based controllers automatically accomplish the detailed control. The primary underwater apparatus has a team of two identical mobile robots designed to travel along opposite surfaces of the pier while connected to each another by a cable and winch system. Each robot has rubber tracks or wheels with cleats and is driven by internal motors. Tensioning the cables that connect the two robots provides traction. The robots can move both vertically and horizontally. While each robot operates its own drive motors and cable winches, coordination of movement and cable tensioning occurs automatically through feedback between the robots and the control console. Multiple robots, evenly spaced around a support column, may inspect larger structures     

Fluid flow through lances with constant and variable pitch swirled inserts

Sirosmelt-type gas injection systems for submerged combustion in metallurgical baths use tubular lances with single or multistart-type helical vane swirlers in the annular region. These inserts not only promote heat transfer from the tube wall to the gas flowing through the tube but also increase pressure drop across the lance. The total pressure loss across such inserts is due to entrance effects and fully developed flow losses. These losses can be quite substantial depending upon the gas flow rate and configuration of inserts. In this paper, a comparison has been made between fixed and variable pitch inserts as far as pressure drop is concerned. A simple flow model has been proposed to describe the flow characteristics of both types of insert. An understanding of these flow characteristics forms a basis for improved lance designs. formerly Research Fellow, G.K. Williams Centre for Extractive Metallurgy, Department of Chemical Engineering, University of Melbourne, Victoria 3052, Australia     

Cadmium-binding protein components of flaxseed: Influence of cultivar and location

The distribution of cadmium-(Cd)-binding components from five flaxseed cultivars grown at three locations in southern Manitoba was investigated to examine genotypic and environmental effects. Three protein fractions with different electrostatic properties, eluting at 0.10, 0.25 and 0.50 M NaCl by ion-exchange chromatography DEAE-Sephacel, represented 12%, 66% and 7% of the bound (extracted) protein, respectively, while 15% of the protein remained unbound. Cadmium and other divalent metal (zinc, copper and calcium) contents of protein fractions were strongly influenced by location. Cultivar differences in protein and cadmium contents of the protein fractions were highly significant. Cadmium and zinc accumulated similarly in the 0.10 and 0.25 M protein fractions at 51% and 40–43%, respectively. Transfer of copper occurred prominently in the 0.50 M fraction while most of the calcium (55%) remained unbound. The distribution of cadmium, zinc, copper and calcium in fractions of flaxseed proteins was strongly influenced by cultivar and location, indicating differences in their accumulation, migration and transfer.     

Hybrid magnetic tunnel junction/vertical cavity surface emittinglaser field sensor device

A hybrid magneto-optoelectronic device is demonstrated, composed of a magnetic tunnel junction and a vertical cavity surface emitting diode laser. External magnetic field changes are translated into amplitude modulation of the laser output power with sensitivity that suggests applications in wireless and remote sensing of magnetic fields     

Tracking human faecal contamination in tropical reservoirs in Puerto Rico

Using a combination of chemical and microbiological (culture-dependent and -independent) approaches, sources of human faecal contamination were identified in two water reservoirs in Puerto Rico – Guajataca and La Plata. Fluorescence from optical brighteners (OB) – commonly found in laundry detergents – was used as an indicator of contamination from septic systems and other household discharges. Traditional indicators of faecal contamination (e.g. Escherichia coli; faecal enterococci) were enumerated, and human faecal contamination was confirmed through detection of Bifidobacterium adolescentis utilizing polymerase chain reaction (PCR)-based analyses. For Guajataca Reservoir, four of 19 sampling sites (21%) were positive for the presence of B. adolescentis under baseflow conditions. The OB fluorescence data suggested that the most likely source for three of these sites was residential, whereas the source of contamination at the remaining site, although of human origin, was probably non-residential. B. adolescentis was present in 83% (19 of 23) of the sampling sites in La Plata. The La Plata sources were more difficult to identify because samples were taken under stormflow conditions, although the presence of OB fluorescence suggested a residential origin in a number of instances. OB fluorescence and traditional bacterial indicators of faecal contamination produced a number of false positive and negative findings for both reservoirs, pointing to the importance of understanding the limitations of these tools for tropical freshwater systems. The results of this study should be useful in developing a weight-of-evidence approach for the identification of potential sources and extent of human faecal contamination in similar tropical reservoirs, a necessary step in the development of management plans to reduce or eliminate these sources.