Removal processes for tributyltin during municipal wastewater treatment

This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2013 Springer.The fate and behaviour of tributyltin (TBT) at two wastewater treatment works was examined. Both sites had two inlet streams, and each utilised high rate biological filters (biofilters) on one the streams, before treatment of the combined flows on trickling filters, with one having additional tertiary processes, installed to remove ammonia and solids. The study was designed to determine if these processes enhanced the removal of TBT. Degradation of TBT was observed in one of the biofilters, possibly as a result of temperature and hydraulic loading. At the treatment works with tertiary processes, the mass flux showed the overall removal of TBT was 68 %, predominantly due to removal with solids in the primary settlement processes. However, overall removal of 95 % was observed in the conventional trickling filter works with 94 % of this due to biodegradation in the trickling filter. The two works both removed TBT, but at different treatment stages and by different processes. Differences in the form (solubility) of TBT in the influent may have attributed to this, although further understanding of factors controlling degradation would allow for a more complete assessment of the potential of biological processes to remove hazardous compounds from wastewaters.United Utilities PL

Non-Newtonian Mixed Thermo-Elastohydrodynamics of Hypoid Gear Pairs

Transmission efficiency is the main objective in the development of vehicular differential systems, comprising hypoid gear pairs. The overall aim is to contribute to improved vehicle fuel efficiency and thus levels of harmful emissions for modern desired eco-drive axles. Detailed predictive analysis plays an important role in this quest, particularly under realistic operating conditions, comprising high contact loads and shear rates. Under these conditions, the hypoid gear pairs are subject to mixed non-Newtonian thermo-elastohydrodynamic conditions, which is the approach undertaken in this paper. Such an approach for hypoid gear pair has not hitherto been reported in the literature

Trombe walls with nanoporous aerogel insulation applied to UK housing refurbishments

There is an opportunity to improve the efficiency of passive Trombe walls and active solar air collectors by replacing their conventional glass covers with lightweight polycarbonate panels filled with nanoporous aerogel insulation. This study investigates the thermal performance, energy savings, and financial payback period of passive Aerogel Trombe walls applied to the existing UK housing stock. Using parametric modeling, a series of design guidance tables have been generated, providing estimates of the energy savings and overheating risk associated with applying areas of Trombe wall to four different house types across the UK built to six notional construction standards. Calculated energy savings range from 183 kWh/m2/year for an 8 m2 system retrofitted to a solid walled detached house to 62 kWh/m2/year for a 32 m2 system retrofitted to a super insulated flat. Predicted energy savings from Trombe walls up to 24 m2 are found to exceed the energy savings from external insulation across all house types and constructions. Small areas of Trombe wall can provide a useful energy contribution without creating a significant overheating risk. If larger areas are to be installed, then detailed calculations would be recommended to assess and mitigate potential overheating issues.The EPSRC, Brunel University, and Buro Happold Lt

Friction Laws for Elastic Nano-Scale Contacts

The effect of surface curvature on the law relating frictional forces F with normal load L is investigated by molecular dynamics simulations as a function of surface symmetry, adhesion, and contamination. Curved, non-adhering, dry, commensurate surfaces show a linear dependency, F proportional to L, similar to dry flat commensurate or amorphous surfaces and macroscopic surfaces. In contrast, curved, non-adhering, dry, amorphous surfaces show F proportional to L^(2/3) similar to friction force microscopes. In our model, adhesive effects are most adequately described by the Hertz plus offset model, as the simulations are confined to small contact radii. Curved lubricated or contaminated surfaces show again different behavior; details depend on how much of the contaminant gets squeezed out of the contact. Also, it is seen that the friction force in the lubricated case is mainly due to atoms at the entrance of the tip.Comment: 7 pages, 5 figures, submitted to Europhys. Let

Lean Project Management as a facilitator of Organisational Learning

The utility and impact of lean principles remains a point of contention (Staats et al, 2011) and few research studies have attempted to link lean project management (LPM) thinking with overall learning and knowledge success from a behavioural perspective (Hines et al, 2004). Those who have done so, have used lean project management principles to highlight singular process-related, task-driven systems and identify barriers in improving operational procedures (Spear, 2005; Poksinska, 2010; Staats et al, 2011) rather than investigating the potential link between desired outcomes and behaviours (Nidumolu & Subramani, 2003). Such studies have limited the progress of LPM as a viable change initiative in solution-focused environments. In this paper, we explore the utility of lean project management against a background of complexity and uncertainty and consider if, and how, LPM can facilitate learning within organisations to establish and sustain improvements for economic success

Oxidation of tertiary amine-derivatized surfaces to control protein adhesion

Selective oxidation of omega-tertiary amine self-assembled thiol monolayers to tertiary amine N-oxides is shown to transform the adhesion of model proteins lysozyme and fibrinogen upon them. Efficient preparation of both secondary and tertiary linker amides as judged by X-ray photoelectron spectroscopy (XPS) and water droplet contact angle was achieved with an improved amide bond formation on gold quartz crystal microbalance (QCM) sensors using 2-(1H-7-azabenzotriazol-1-yl)-1,1,3,3-tetramethyl hexafluorophosphate methanaminium uronium (HATU). Oxidation with hydrogen peroxide was similarly assessed, and adhesion of lysozyme and fibrinogen from phosphate buffered saline was then assayed by QCM and imaged by AFM. Tertiary amine-functionalized sensors adsorbed multilayers of aggregated lysozyme, whereas tertiary amine N-oxides and triethylene glycol-terminated monolayers are consistent with small protein aggregates. The surface containing a dimethylamine N-oxide headgroup and ethyl secondary amide linker showed the largest difference in adsorption of both proteins. Oxidation of tertiary amine decorated surfaces therefore holds the potential for selective deposition of proteins and cells through masking and other patterning techniques

An Investigation into the Oil Transport and Starvation of Piston-Ring Pack

In order to accurately predict the lubricant film thickness and generated friction in any tribological contact, it is important to determine appropriate boundary conditions, taking into account the oil availability and extent of starvation. This paper presents a two-dimensional hydrodynamic model of a piston ring pack for prediction of lubricant film thickness, friction and total power loss. The model takes into account starvation caused by reverse flow at the conjunctional inlet wedge, and applied to a ring pack, comprising a compression and scraper ring. Inlet boundaries are calculated for an engine cycle of a four-cylinder, four-stroke gasoline engine operating at 1500 r/min with conditions pertaining to the New European Drive Cycle. The analysis shows the two main sources of starvation: first, due to a physical lack of inlet meniscus and second, due to reverse flow at the inlet wedge significantly affecting the prevailing conditions from the generally assumed idealised boundary conditions. Such an approach has not hitherto been reported in literature

The prediction of liquid film journal bearing performance with a consideration of lubricant film reformation: part 2: experimental resuIts

Analyses and design data for plainjournal bearings rarely take into account the phenomenon of film reformation. The consideration of the re-establishment of the lubricantfilm after the cavitation region is difficult in a number of ways. The importance of allowingfor reformation is, however, being increasingly recognized. Tht.J is particularly true as regards the satisfactory predlction of lubricant ftowrate...and the thermal operating characteristics of a bearing. The authors have previously implemented a cavitation algorithm to enable the cavitation region in a plain journal bearing to be Iocated automatically and efficiently in a computer analysis. In Part I of the present paper theoretical results have been presentedfor the case of a plain bearing with a square-ended, axial groove located at the position of maximumfilm thickness. The second part of the paper gives detai/s of an experimental investigation designed to establish the validity of the analysis

Dynamic friction force in a carbon peapod oscillator

We investigate a new generation of fullerene nano-oscillators: a single-walled carbon nanotube with one buckyball inside with an operating frequency in the tens-of-gigahertz range. A quantitative characterization of energy dissipation channels in the peapod pair has been performed via molecular dynamics simulation. Edge effects are found to the dominant cause of dynamic friction in the carbon-peapod oscillators. A comparative study on energy dissipation also reveals significant impact of temperature and impulse velocity on the frictional force.Comment: 17 pages, 3 fig., 1 tabl