On plastic potentials for anisotropic metals and their derivation from the texture function

Summary Plastic yielding of anisotropic metals can be either described by a macroscopic constitutive relation or assessed by means of a model which correlates single and polycrystal behaviors. The mathematical identification of the plastic work rate derived from the two approaches, for all strain rate tensors, leads to a fit of the polycrystal yield surface by an analytical function. When a quadratic from is assumed, the macroscopic anisotropy parameters become explicit functions of the texture coefficients. This identification method is applied to calculate yield surfaces andR-values of rolled and annealed steel sheets: theR-values and in general the flow rule, are more significantly modified by the fitting than the yield surface. Thus, it is worth extending the method to more general constitutive relations which may be given by the form of their work function: alternative forms of the work function for plastic materials are explored, especially in the bearing of convexity and homogeneity where quadratic forms have a distinct advantage. Finally, it is shown that the identification of the work function allows to express the phenomenological coefficients as analytical functions of the texture parameters for many forms of the work function; in the other cases, these coefficients may be obtained by linear or non-linear regression.     

Wastewater treatment in tsunami affected areas of Thailand by constructed wetlands.

The tsunami of December 2004 destroyed infrastructure in many coastal areas in South-East Asia. In January 2005, the Danish Government gave a tsunami relief grant to Thailand to re-establish the wastewater management services in some of the areas affected by the tsunami. This paper describes the systems which have been built at three locations: (a) Baan Pru Teau: A newly-built township for tsunami victims which was constructed with the contribution of the Thai Red Cross. Conventional septic tanks were installed for the treatment of blackwater from each household and its effluent and grey water (40 m3/day) are collected and treated at a 220 m2 subsurface flow constructed wetland. (b) Koh Phi Phi Don island: A wastewater collection system for the main business and hotel area of the island, a pumping station and a pressure pipe to the treatment facility, a multi-stage constructed wetland system and a system for reuse of treated wastewater. The constructed wetland system (capacity 400 m3/day) consists of vertical flow, horizontal subsurface flow, free water surface flow and pond units. Because the treatment plant is surrounded by resorts, restaurants and shops, the constructed wetland systems are designed with terrains as scenic landscaping. (c) Patong: A 5,000 m2 constructed wetland system has been established to treat polluted water from drainage canals which collect overflow from septic tanks and grey water from residential areas. It is envisaged that these three systems will serve as prototype demonstration systems for appropriate wastewater management in Thailand and other tropical countries.     

Zur linearanalytischen Dichtebestimmung von Buchenholz

Earlier investigations on the determination of beech wood density by linear analysis gave an unsatisfactory correlation of results with those of conventionally determined specific gravity. In this report an example is used to show that a decided correction of results is possible if the density of broad xylem rays is determined separately from that of the remaining tissues on the one hand, and if the measurement of the percentage of cell wall cross area is supported by findings in several levels. This, however, increases the microtechnical costs to such an extent that the method appears practicable in exceptional cases only.     

Kinetic studies of the electrochemical reaction between lithium and phthalocyanine II. Reduction reaction mechanism

The effects, during formation, of current density, charge capacity, and concentration and temperature of H₂SO₄ electrolyte on the capacity of tubular electrodes in lead/acid batteries have been studied. Electrode capacity was found to be maximum at a H₂SO₄ concentration of 1.05 sp. gr., a charge amount of 250% theoretical capacity, a current density of 0.44 A dm^?2, and an electrolyte temperature of 40 °C. A study of the soaking process for tubular electrodes showed the electrode capacity to be maximum when the acid absorption was about 170 mg of H₂SO₄ per g of oxide. Finally, the discharge overpotential of tubular electrodes was analyzed by a galvanostatic transient method.     

The role of systems and applications monitoring in operational risk management

Operational risk management is a reflection of the need for enterprises to demonstrate that they are prepared for all eventualities, through monitoring day-to-day operational risks. IT is an area that is critical to modern enterprises and consequently carries with it the capacity to cripple those same enterprises — business disruption as a result of IT failure is a major area of operational risk. Modern IT in many enterprises, especially large ones such as BT, is distributed and heterogeneous. This presents challenges to collecting and correlating management, monitoring and audit data in a timely manner. It also highlights the need to take an end-to-end view, with data collected from a number of sources and presented as an integrated picture of the health of a business solution. In an eBusiness environment, there is also a need to manage, monitor and audit the IT interfaces with customers, suppliers and partners. This paper looks at operational risk in an IT context and provides an overview of the contribution made by systems and applications monitoring to successful operational risk management. This paper has concentrated on using monitoring to address the downside of risk and reflects a culture in many organisations to eliminate or minimise risk. However, risk has an upside whereby an enterprise can gain competitive advantage through ‘right setting’ risk tolerance — this advantage can only be gained when the organisation begins to understand and articulates its risk appetite. Monitoring can contribute significantly to the upside through supplying the information required to manage and control the risk exposure to perform within the accepted risk appetite, facilitate risk taking and imbue a better risk culture in the organisation.     

Effect of pulse duration and size of interelectrode interval on electric-spark spraying. I. Effect of pulse duration and size of interelectrode interval on rate of electric-spark transfer

The influence exerted by electric-spark spraying on the kinetics of mass transfer and the physicomechanical properties of coatings is investigated. It is shown that electric-spark spraying is determined by the dynamic properties of the cathode jets, which depend on the electrical parameters of the spark discharge, the size of the interelectrode interval, and the physical properties of the coatings, which vary during spraying.     

Simultaneous visualisation of biofouling, organic and inorganic particle fouling on separation membranes.

Fouling is a major problem in membrane processes of water treatment. It can be caused by the deposition of inorganic and organic particulate material, and of microbial cells which may subsequently form biofilms. In practice, usually more than one foulant participates in the formation of membrane deposits. Knowledge of the composition of fouling layers is important for the development of appropriate countermeasures. For this purpose, an experimental system was established for the generation and microscopic visualisation of mixed deposits, using fluorescently labelled model foulants: (i) drinking-water bacteria stained with nucleic acid-specific dyes (biofouling), (ii) synthetic clay mineral laponite stained with rhodamine 6G (inorganic particle fouling), and (iii) fluorescently labelled polystyrene microspheres (organic particle fouling). Polycarbonate and polyethersulfone membranes were challenged with these foulants by dead-end filtration. On the basis of different fluorescent labels, the single foulants in these mixed deposits could be visualised separately by confocal laser scanning microscopy which, in combination with image analysis, allowed the generation of three-dimensional views of the complete deposits. This method offers the possibility for the estimation of quantitative surface coverage by foulants and for the determination of the efficacy of cleaning measures with respect to the removal of different foulants.