A novel multi-electrode system for electrolytic and biological water treatments: electric charge transfer and application to denitrification

A novel multi-electrode system is proposed for electrolytic and biological water treatments. The multi-electrode system is comprised of multiple working electrodes and their counter electrode, where electric current or potential applied to each electrode is controlled independently. Experimental result for different electrolyte solutions showed that electric charge in the system was efficiently carried by dissociative electrolytes such as carbonate ions. This transfer mechanism is regarded as being effective both in keeping pH level around neutrality and in passing certain amounts of electric current especially in dilute solutions such as groundwater and surface water. A long-term (over 500 days) experiment also showed the enhanced and stable denitrification performance of biofilm-electrode reactor (BER) equipped with the multi-electrode system, comparing to former BERs. This superior performance was thought to be attributable to large effective surface area of electrode, the charge transfer mechanism by dissociative electrolyte, and the formation of highly reducing (or oxidizing) zones. From these results, we conclude that the multi-electrode system is useful for electrolytic and biological treatments of groundwater and surface water.     

A framework for rapid local area modeling for construction automation

Rapid 3D positioning and modeling in construction can be used to more effectively plan, visualize, and communicate operations before execution. It can also help to optimize equipment operations, significantly improve safety, and enhance a remote operator's spatial perception of the workspace. A new framework for rapid local area sensing and 3D modeling for better planning and control of construction equipment operation is described and demonstrated. By combining human-assisted graphical workspace modeling with pre-stored Computer-Aided Design (CAD) models and simple sensors (such as single-axis laser rangefinders and remote video cameras), modeling time can be significantly reduced while potentially increasing modeling accuracy.     

The use of roughness to produce high reynolds number flows around circular cylinders at lower reynolds numbers

It has long been stated that the pressure distribution around a circular cylinder at high values of Reynolds number can be reproduced at lower values of Reynolds number by a suitable roughening of the surface of the cylinder. This paper shows that this is indeed possible and explains the problems.     

Limit analysis of reinforced concrete cylindrical shell roofs

Two approximate yield criteria are proposed for reinforced concrete cylindrical shell element. Three lower bound solutions are developed for cylindrical shell roofs with free longitudinal edges. Two shells with different geometric parameters are analysed. Elastic analysis is also done at working load. Graphs are presented to show the variation of stress resultants at critical sections.     

Determination of labile and strongly bound metals in lake water

Differential pulse anodic stripping voltammetry is applied to differentiate and determine the labile and strongly bound forms of Zn, Cd, Pb and Cu in lake water without preconcentration of the sample. The sensitivities as established for an oxidation peak current of 0·020 μA are: 0·2 ppb for Zn. 0·4 ppb Cd. 0·7 ppb Pb and 0·5 ppb for Cu. For the analysis of a lake water containing 5·0–24·5 ppb of the four metals, the relative S.D. ranged from 1·6 to 10 per cent. Interferences of cations and anions and the choice of a buffer system have been discussed. The method has been applied to study a number of small lakes in the Sudbury area. Ontario.     

Finite element modelling of plate girders with web openings

This paper is concerned with a finite element model to predict the behaviour and ultimate load of plate girders with web openings. The finite element package is used to model the plate girders with web openings. Accuracy of the model is assessed by applying it to plate girders tested earlier by other researchers. Comparison of analytical results with the available experimental results for yielding patterns, ultimate load values and load–deflection relationships show good agreement between the finite element and experimental results thus validating the accuracy of the proposed model. The proposed finite element method was extended to carry out a parametric study. The study covered parameters such as web slenderness and flange stiffness.