An improved approximation algorithm for the two-machine flow shop scheduling problem with an interstage transporter

We study the two-machine flow shop problem with an uncapacitated interstage transporter. The jobs have to be split into batches, and upon completion on the first machine, each batch has to be shipped to the second machine by a transporter. The best known heuristic for the problem is a –approximation algorithm that outputs a two-shipment schedule. We design a –approximation algorithm that finds schedules with at most three shipments, and this ratio cannot be improved, unless schedules with more shipments are created. This improvement is achieved due to a thorough analysis of schedules with two and three shipments by means of linear programming. We formulate problems of finding an optimal schedule with two or three shipments as integer linear programs and develop strongly polynomial algorithms that find solutions to their continuous relaxations with a small number of fractional variables

Industrial water pollution in Dhaka, Bangladesh: strategies and incentives for pollution control in small and medium enterprises

The extent and gravity of the environmental degradation of the water resources in Dhaka due to untreated industrial waste is not fully recognised in international discourse. Pollution levels affect vast numbers, but the poor and the vulnerable are the worst affected. For example, rice productivity, the mainstay of poor farmers, in the Dhaka watershed has declined by 40% over a period of ten years. The study found significant correlations between water pollution and diseases such as jaundice, diarrhoea and skin problems. It was reported that the cost of treatment of one episode of skin disease could be as high as 29% of the weekly earnings of some of the poorest households. The dominant approach to deal with pollution in the SMEs is technocratic. Given the magnitude of the problem this paper argues that to control industrial pollution by SMEs and to enhance their compliance it is necessary to move from the technocratic approach to one which can also address the wider institutional and attitudinal issues. Underlying this shift is the need to adopt the appropriate methodology. The multi-stakeholder analysis enables an understanding of the actors, their influence, their capacity to participate in, or oppose change, and the existing and embedded incentive structures which allow them to pursue interests which are generally detrimental to environmental good. This enabled core and supporting strategies to be developed around three types of actors in industrial pollution, i.e., (i) principal actors, who directly contribute to industrial pollution; (ii) stakeholders who exacerbate the situation; and (iii) potential actors in mitigation. Within a carrot-and-stick framework, the strategies aim to improve environmental governance and transparency, set up a packet to incentive for industry and increase public awareness.

Constructive notice and independent legal advice: a study of lending institution practice

Cases on when lending institutions will be put on inquiry as to circumstances giving rise to presumption of undue influence, and results of research on lending practice of residential mortgage lenders in light of case law. [From Legal Journals Index]

Thermoelectric MHD in dendritic solidification

The effects of a constant uniform magnetic field on dendritic solidification were investigated using an enthalpy based numerical model. The interaction between thermoelectric currents on a growing crystal and the magnetic field generates a Lorentz force that creates flow. The need for very high resolution at the liquid-solid boundary where the thermoelectric source originates plus the need to accommodate multiple grains for a realistic simulation, make this a very demanding computational problem. For practical simulations, a quasi 3-dimensional approximation is proposed which nevertheless retains essential elements of transport in the third dimension. A magnetic field normal to the plane of growth leads to general flow circulation around an equiaxed dendrite, with secondary recirculations between the arms. The heat/solute advection by the flow is shown to cause a change in the morphology of the dendrite; secondary growth is promoted preferentially on one side of the dendrite arm and the tip velocity of the primary arm is increased. The degree of approximation introduced is quantified by extending the model into 3-dimensions, where the full Navier-Stokes equation is solved, and compared against the 2-dimensional solution.