We present a theory for spin excitations in ferromagnetic metallic manganites and demonstrate that orbital fluctuations have strong effects on the magnon dynamics in the case these compounds are close to a transition to an orbital ordered state. In particular we show that the scattering of the spin excitations by low-lying orbital modes with cubic symmetry causes both the magnon softening and d...

Employing the technique of vanishing viscosity and time rescaling, we show the existence of quasistatic evolutions for elastoplastic materials with incomplete damage affecting both the elastic tensor and the plastic yield surface, in a softening framework and in small strain assumptions.

In many selling situations, the firm can choose between a selling format in which the buyer determines which information about the product will be revealed and one in which the seller makes this determination. We model this choice of information revelation format and its interaction with product quality. In a monopoly with exogenous quality, if the firm offers a high quality product it prefers ...

We study the spatially uniform case of the problem of quasistatic evolution in small strain nonassociative elastoplasticity (Cam-Clay model). Through the introdution of a viscous approximation, the problem reduces to determine the limit behavior of the solutions of a singularly perturbed system of ODE’s in a finite dimensional Banach space. Depending on the sign of two explicit scalar indicator...

Apricots (Prunus armeniaca L.), a kind of climacteric fruits, are favored by consumers for their flavor and texture, but they are highly perishable. Apricots soften rapidly after harvest. Once softened, they are easily damaged such as latent damage, which limits their marketing time [1, 2]. Therefore, a common practice for handling and storing apricots is early harvest and applying postharvest ...

We study a relaxed formulation of the quasistatic evolution problem in the context of small strain associative elastoplasticity with softening. The relaxation takes place in spaces of generalized Young measures. The notion of solution is characterized by the following properties: global stability at each time and energy balance on each time interval. An example developed in detail compares the ...

In recent years it has become possible to study the properties of nanocrystalline metals through atomic-scale simulations of systems with realistic grain sizes. A brief overview of the main results is given, such as the observation of a reverse Hall-Petch effect — a softening of the metal when the grain size is reduced. The limitations of computer simulations are discussed, with a particular fo...

A deeper understanding of the mechanical behavior of ultra-fine (UF) and nanocrystalline (NC) grained metals is necessary with the growing interest in using UF and NC grained metals for structural applications. The cyclic deformation response and behavior of UF and NC grained metals is one aspect that has been gaining momentum as a major research topic for the past ten years. Severe Plastic Def...

ing momentum p from ζ(q, ω) in equation (14) results to a relation 〈〈c†p+q,↑cp,↓;S (0, 0)〉〉 = cJ 2 〈c†p,↓cp,↓〉 − 〈c † p+q,↑cp+q,↑〉 ω − εp + εp+q − cJ〈Sz〉 ×G(q, ω). (15) Combining equations (10) and (14) results to a closed form of Green’s function equation G(q, ω), (ω − cJ〈σ〉 + cJ 2 〈S〉 ∑ p 〈c†p,↓cp,↓〉 − 〈c † p+q,↑cp+q,↑〉 ω − εp + εp+q − cJ〈Sz〉 )