Composition and thermal stability of SiO2-based hybrid materials TEOS-MTEOS system

Hybrid materials with different amounts of organics permanently bound on the inorganic network obtained in the TEOS-MTEOS (tetraethoxysilan-methyltriethoxysilan) system are used for obtaining coatings with different optical and mechanical properties. To study the thermal stability of the mentioned materials, compositions with different molar ratios of the precursors were prepared. The influence of the solvent and water amounts on the gelation process was also investigated. The gels obtained were characterised by IR spectrometry and their decomposition temperatures were determined by DTA/TG. Thermal stability of the gels is rather influenced by their composition than the conditions of the gelation process. This revised version was published online in July 2006 with corrections to the Cover Date.     

Radiation dose contribution from coal-slags used as structural building material

A significant dose contribution on the population could be derived from coal slags used as isolation material. Extremely high natural activities are measured in the coal slag, derived from the region of the settlement Ajka, Hungary. In some buildings monitored, the elevated -doses were nearly 5–10 times higher than the world average ones. The annual average indoor radon concentrations from the slag exceeded 400 Bq/m³ and in some cases up to 1200 Bq/m³. Due to the elevated exposure and the radon concentrations in the dwellings the annual dose was estimated to 8–24 mSv/y more than 5–10 times of the world average one.     

CIRCULAR DICHROISM SPECTRA OF SYSTEM I PARTICLES FROM NORMAL CHLOROPLASTS AND CAROTENOID-DEFICIENT MUTANTS OF MAIZE

Abstract— Circular dichroism (CD) spectra were studied in System I particles prepared by digitonin fragmentation of chloroplasts of normal maize and carotenoid-deficient mutants. CD bands of pigment molecules were found to be higher in particles than in solutions. This phenomenon was most pronounced for the particles containing the carotenoid composition of normal chloroplast lamellae. The CD signal of chlorophylls bound to particles of carotenoid-deficient chloroplasts was closer to that found in solutions. This indicates that aggregation and/or binding of chlorophylls in carotenoid-deficient mutants may be less extensive than in normal chloroplasts.     

The maximum return-on-investment plant location problem

The standard plant location problem determines which plants to open from a set of potential sites in order to satisfy the demands at a set of customer vertices at a minimum total cost. However, the optimal solution may exceed a limit on investment costs imposed on the enterprise in a practical setting. This paper examines the plant location problem in an environment in which the investment in plant and equipment is also an objective to be minimised. The problem is posed as a bicriterion model which examines the tradeoff between the sum of operational and investment costs and investment cost (or total cost vs sunk cost). A weighting method is used to generate efficient solutions, one of which is shown to maximise the return on investment. The integer-friendliness of the LP relaxation is investigated.     

Adaptation of the plant location model for regional environmental facilities and cost allocation strategy

This paper is divided into two parts. In the first part of the paper, the plant location model is adapted for the special case of siting wastewater treatment facilities when the wastewater sources and treatment facilities are arranged in a chain or linear configuration. In this problem, flows or shipments may be merged in common pipes that provide economies of scale in transport. In order to apply the plant location model, an appropriate definition of the additional cost incurred when a waste source joins a regional facility is required. In addition, sequential priority constraints are developed in the siting model in order to make possible proper accounting of transport costs. The new siting model can be conveniently solved by linear programming.In the second part of the paper, a dual of the plant location model is explored as a cost allocation method for the fixed charge facility siting problem. The constraint sets of the dual model can be shown to imply the core conditions of the related cost game; hence, a set of the dual variables from the dual problem can be regarded as rational cost allocations. The analysis places both facility siting and cost allocation in a common framework.     

Linear,non-approximated models for optimal routing in hazardous environments

A linear optimisation model is presented for the routing of vehicles through hazardous environments or for routing vehicles carrying hazardous materials. The model seeks to find the route with the minimum cost and the minimum probability of accident. As opposed to previously published models, the formulation is linear and no approximations are needed, even in the case of high risk. Several forms of considering risk are presented, as well as a simple method of solution in polynomial time. An example is shown and solved.     

Evaluating environmental quality management programmes in which dischargers are grouped

A method is presented for evaluating management programmes in which the dischargers are divided into groups. Analogous non-linear mathematical formulations are presented for direct regulation and effluent charge programmes, and a non-linear branch-and-bound solution procedure is described. A detailed algorithm is described for the effluent charge case; it is shown to be very practical in an application to data for the Delaware estuary.     

Differentiable Distance Spaces

The distance function \({\varrho(p, q) ({\rm or} d(p, q))}\) of a distance space (general metric space) is not differentiable in general. We investigate such distance spaces over \({\mathbb{R}^n}\), whose distance functions are differentiable like in case of Finsler spaces. These spaces have several good properties, yet they are not Finsler spaces (which are special distance spaces). They are situated between general metric spaces (distance spaces) and Finsler spaces. We will investigate such curves of differentiable distance spaces, which possess the same properties as geodesics do in Finsler spaces. So these curves can be considered as forerunners of Finsler geodesics. They are in greater plenitude than Finsler geodesics, but they become geodesics in a Finsler space. We show some properties of these curves, as well as some relations between differentiable distance spaces and Finsler spaces. We arrive to these curves and to our results by using distance spheres, and using no variational calculus. We often apply direct geometric considerations.