Very large street routing problem with mixed transportation mode

Providers of logistic services in recent years are under a big pressure to lower their expenses. One way to accomplish this task is centralization of logistic activities. This creates a distribution centers with a large number of customers. The capacity or time of one delivery person is limited, but, at the same time, it usually serves many customers. This problem is often called a Street Routing Problem (SRP). This paper is a survey of aggregation heuristics that can be used for a solution of Very Large SRP (VLSRP). Performance of heuristics has been evaluated based on real data. This paper presents several approximations of length for a SRP with mixed transportation mode and compares them with published approximations used for Vehicle Routing Problem (VRP) or Traveling Salesman Problems (TSP). The method was tested in seven real world instances ranging from 11000 to 29000 customers. Several aggregation methods including two new are presented and compared for the creation of delivery districts. New measurements for the quality of aggregation are created and tested on real data with all discussed aggregation methods.     

Sorption of Arsenic Oxyanions from Aqueous Solution on Goethite: a Study of Process Modelling

In the course of researching methods of sampling and monitoring toxic metals (as arsenic ions) in water and wastewaters, we selected the use of sorption for in-depth examination. Among other things, sorption modelling was investigated by the mechanism of surface complexation in order to describe the process or even predict the outcome for the expected rate, and in general, to develop this detection technique for pollutants. This investigation will include the application of goethite mineral as the suitable metal ion sorbent and the use of appropriate computer software. The relative thermodynamic aqueous speciation of the solution, in similar experimental conditions, was also studied.     

Nuclear multifragmentation, percolation, and the fisher droplet model: common features of reducibility and thermal scaling

It is shown that the Fisher droplet model, percolation, and nuclear multifragmentation share the common features of reducibility (stochasticity in multiplicity distributions) and thermal scaling (one-fragment production probabilities are Boltzmann factors). Barriers obtained, for cluster production on percolation lattices, from the Boltzmann factors show a power-law dependence on cluster size with an exponent of 0.42+/-0.02. The EOS Collaboration Au multifragmentation data yield barriers with a power-law exponent of 0.68+/-0.03. Values of the surface energy coefficient of a low density nuclear system are also extracted.     

Biosorption of Metals from Dilute Aqueous Solutions

Dilute aqueous solutions, generated or used by industry, can contain a variety of different metal ions. Various processes are suitable for reclamation of toxic metals and among them, attention is paid here to biosorption. The ability of microorganisms to remove metal ions from solution is a well known phenomenon. Industrial applications of biosorption often make use of dead biomass, which does not require nutrients and can be exposed to environments of high toxicity. Experimental laboratory batch experiments are described for actinomycetes, fungi and for activated sludge, as the metal biosorbents, providing insight into cadmium biosorption. Non-living biomass showed greater binding capacities for cadmium (a priority pollutant) than living biomass. Engineering considerations are central in decisions concerning the commercial future of biosorption and a practical solution is needed for certain problems, such as the efficient separation of metal-loaded biomass.