Physically based modeling of cyclic plasticity for highly oriented nanotwinned metals

Fatigue resistance is crucial for the engineering application of metals. Polycrystalline metals with highly oriented nanotwins have been shown to exhibit a history-independent, stable and symmetric cyclic response [Pan et al. Nature 551 (2017) 214-217]. However, a constitutive model that incorporates the cyclic deformation mechanism of highly oriented nanotwinned metals is currently lacking. This study aims to develop a physically based model to describe the plastic deformation of highly oriented nanotwinned metals under cyclic loading parallel to the twin boundaries. The theoretical analysis is conducted based on a non-uniform distribution of twin boundary spacing measured by experiments. During cyclic plasticity, each twin lamella is discretely regarded as a perfect elastoplastic element with a yielding strength depending on its thickness. The interaction between adjacent nanotwins is not taken into consideration according to the cyclic plasticity mechanism of highly oriented nanotwins. The modeling results are well consistent with the experiments, including the loading-history independence, Masing behavior and back stress evolution. Moreover, the dissipation energy during cyclic deformation can be evaluated from a thermodynamics perspective, which offers an approach for the prediction of the fatigue life of the highly oriented nanotwins. The cyclic plasticity modeling and fatigue life prediction are unified without fatigue damage parameters. Overall, our work lays down a physics-informed framework that is critical for the precise prediction of the unique cyclic behaviors of highly oriented nanotwins.

Agendas in legislative decision‐making

Despite the wide variety of agendas used in legislative settings, the literature on sophisticated voting has focused on two formats: the so‐called Euro–Latin and Anglo–American agendas. In the current paper, I introduce a broad class of agendas whose defining structural features—history‐independence and persistence—are common in legislative settings. I then characterize the social choice rules implemented by sophisticated voting on agendas with these two features. I also characterize the rules implemented by more specialized formats (called priority agendas and convex agendas) whose structure is closely related to the prevailing rules for order‐of‐voting used by legislatures. These results establish a clear connection between structure and outcomes for a wide range of legislative agendas.

HISTORY OF THE PEOPLE 'S COMMISSARIAT FOR NATIONAL AFFAIRS OF THE TURKISTAN ASSR (1918-1922)

It is well known from history that, in the history of the multi-ethnic people, national issues are of paramount importance. Since the first years of independence, the interest of our people in knowing their Motherland, its language, culture, values and history has increased. KEY WORDS: history, independence, capacity, council, committee, culture, developed people.

PROBLEMS OF PRICING IN THE CONSTRUCTION OF THE KYRGYZ REPUBLIC AND WAYS OF SOLUTIONS

The pricing system was based on the budget and regulatory framework of 1984. August 31, 1991 with the acquisition of independence of the Kyrgyz Republic began a new countdown and its history. Independence also influenced the pricing policy of the Kyrgyz Republic, as the Kyrgyz currency – som was introduced on may 10, 1993. Was chosen course 1 som to 200 rubles. Prior to the development of the new regulatory framework, price coefficients and price indices were used to convert prices into current prices. In this regard, it was decided to develop a new budget and regulatory framework that meets modern realities.

Breach-Resistant Structured Encryption

Motivated by the problem of data breaches, we formalize a notion of security for dynamic structured encryption (STE) schemes that guarantees security against a snapshot adversary; that is, an adversary that receives a copy of the encrypted structure at various times but does not see the transcripts related to any queries. In particular, we focus on the construction of dynamic encrypted multi-maps which are used to build efficient searchable symmetric encryption schemes, graph encryption schemes and encrypted relational databases. Interestingly, we show that a form of snapshot security we refer to as breach resistance implies previously-studied notions such as a (weaker version) of history independence and write-only obliviousness. Moreover, we initiate the study of dual-secure dynamic STE constructions: schemes that are forward-private against a persistent adversary and breach-resistant against a snapshot adversary. The notion of forward privacy guarantees that updates to the encrypted structure do not reveal their association to any query made in the past. As a concrete instantiation, we propose a new dual-secure dynamic multi-map encryption scheme that outperforms all existing constructions; including schemes that are not dual-secure. Our construction has query complexity that grows with the selectivity of the query and the number of deletes since the client executed a linear-time rebuild protocol which can be de-amortized. We implemented our scheme (with the de-amortized rebuild protocol) and evaluated its concrete efficiency empirically. Our experiments show that it is highly efficient with queries taking less than 1 microsecond per label/value pair.