Abstract This paper by reviewing the main examples of small to medium-scale retractable roof structures covering building courtyards is to present an innovative rigid retractable roof system employing spatial frames for a courtyard of an existing building in Tabriz Islamic Art University. The courtyard is currently used for temporary exhibitions and gatherings whenever permitted by environmenta...

Background: During recent years, scientists have presented several methods for treating infertility; these methods occasionally are highly efficient for infertile couples but can be concerning because of legal and ethical issues. One of these methods is surrogacy. Surrogacy is used when the main etiology of infertility is in the uterus caused by these three reasons: lack of uterine‚ congenital ...

This paper concentrates on the representation of the legal relations that obtain between parties once they have entered a contractual agreement and their evolution as the agreement progresses through time. Contracts are regarded as process and they are analysed in terms of the obligations that are active at various points during their life span. An informal notation is introduced that summarize...

Retractable type fall arresters constitute a most effective group of components used in personal protection systems protecting against falls from a height. They are designed primarily for outdoor use, which results in exposure to atmospheric factors associated with risk of corrosion of metal elements. This paper presents the results of a study, in which retractable type fall arresters were expo...

We investigate the finitely repeated prisoners’ dilemma with explicit contractual devices. We show that full collusion can be achieved by incentivizing the players’ final period of play with small fines. Our incentivizing modality is the penance contract, by which a player is penalized if (and only if) he deviates from the penance strategy in the final period. We show that using this contractua...