In this study, the effect of surface crystallography on hydrogen molecule adsorption properties on FeTi surfaces is presented. Furthermore, the substitutional adsorption of 3d-transition metals on (001), (110) and (111) surfaces of FeTi is studied. Using ab initio pseudopotential methods, the adsorption energies of hydrogen and 3d-transition metals are calculated. In substitutional adsorption of 3d-transition metals, Fe-terminated (111) and Ti-terminated (001) surfaces, are found to express the lowest adsorption energies. The adsorption energy versus adsorbed elements&rsquo / curves are very alike for all the surfaces. According to this, going from the left to right of periodic table, the adsorption energies increase first. The maximum energy belongs to Cr, Mn and Fe for all the surfaces. Then a minimum is observed in Co for all the surfaces and after that the energy increases again. Adsorption energies of atomic and molecular hydrogen are calculated on high symmetry sites of surfaces. As a result, top and bridge sites came out to be the most stable positions for molecular and atomic hydrogen adsorption, respectively, for (001) and (111) surfaces in all terminations. In (110) surface / however, 3-fold (Ti-Ti)L-Fe and 3-fold (Ti-Ti)S-Fe hollow sites express the lowest adsorption energies for molecular and atomic hydrogen, respectively. Considering the minimum adsorption energy sites for hydrogen molecule and atom, a path of dissociation of hydrogen molecule on surfaces is represented. After that by fully relaxing the hydrogen molecule on the surface and using CI-NEB method the activation energy for hydrogen dissociation is calculated. So it has been found that on Fe-terminated (111) and FeTi (110) surfaces the dissociation of hydrogen molecule happens without activation energy. Meanwhile, the activation energy for Fe-terminated (001) surface and Ti-terminated (001) surface, is calculated to be 0.178 and 0.190 eV, respectively.

In this thesis, a market is assumed with n competing buyers where price is an inverse linear function of the quantity supplied to the market. The buyers get engaged in Cournot competition, but may also collaborate on purchasing decisions from a supplier. The supplier offers a quantity discount, as the quantity purchased increases unit price decreases. Furthermore, the demand base in the market is uncertain, but the buyers may get a signal of the demand. In this setting, the value of collaboration, information sharing and non-linear pricing is analyzed.

In this thesis, we study on l-K&ouml / the spaces. By the help of interpolation theory, we use linear topological invariants to get isomorphisms of Cartesian products of l-power series spaces. We also see that multirectangular n-equivalent characteristics is linear toplogical invariant for power l-K&ouml / the spaces of first type.

The present work consists of two main parts. In the first part, invariant subspaces of positive operators or operator families on locally convex solid Riesz spaces are examined. The concept of a weakly-quasinilpotent operator on a locally convex solid Riesz space has been introduced and several results that are known for a single operator on Banach lattices have been generalized to families of positive or close-to-them operators on these spaces. In the second part, the so-called generalized Alexandroff duplicates are studied and CDsigma, gamma(K, E)-type spaces are investigated. It has then been shown that the space CDsigma, gamma(K, E) can be represented as the space of E-valued continuous functions on the generalized Alexandroff duplicate of K.

In this thesis, we study two problems. The first problem is to introduce the general version of Abramovich-Wickstead type spaces and investigate its order properties. In particular, we study the ideals, order bounded sets, disjointness properties, Dedekind completion and the norm properties of this Riesz space. We also define a new concrete example of Riesz space-valued uniformly continuous functions, denoted by CDr0 which generalizes the original Abramovich-Wickstead space. It is also shown that similar spaces CD0 and CDw introduced earlier by Alpay and Ercan are decomposable lattice-normed spaces. The second problem is related to analytic representations of different classes of dominated operators on these spaces. Our main representation theorems say that regular linear operators on CDr0 or linear dominated operators on CD0 may be represented as the sum of integration with respect to operator-valued measure and summation operation. In the case when the operator is order continuous or bo-continuous, then these representations reduce to discrete parts.

The concept of LR-nets was introduced and investigated firstly by H.P. Lotz in [27] and by F. Raebiger in [30]. Therefore we call such nets Lotz-Raebiger nets, shortly LR-nets. In this thesis we treat two problems on asymptotic behavior of these operator nets. First problem is to generalize well known theorems for Ces`aro averages of a single operator to LR-nets, namely to generalize the Eberlein and Sine theorems. The second problem is related to the strong convergence of Markov LR-nets on L1-spaces. We prove that the existence of a lower-bound functions is necessary and sufficient for asymptotic stability of LR-nets of Markov operators.