Asphalt mortar and asphalt mixture are viscoelastic materials due to the presence of bitumen in their structures. The master curves of dynamic modulus and phase angle developed through the horizontal shifting of the results using the appropriate shift factors are commonly used to describe the viscoelastic properties of asphalt mortar and asphalt mixture. In this study, constructing master curves of dynamic modulus and phase angle of asphalt mortar and asphalt mixture using the least number of test temperatures and frequencies was investigated. The dynamic modulus test was performed on asphalt concrete and asphalt mortar samples at six temperatures and frequencies. Then, the Laboratoire Central des Ponts et Chaussees method was used to determine the shift factors for constructing master curves. Also, the modified Christensen-Anderson-Marasteanu model was fitted on the master curves to predict their viscoelastic properties at an arbitrary temperature and frequency. In addition, the master curves and the fitted models, which are created by using test results at two frequencies and six temperatures, six frequencies and three temperatures, or three frequencies and three temperatures, could provide the same predicted values and patterns as the original fitted model with more than 92% accuracy. So, as a result, it is possible to develop the master curves of the viscoelastic properties of asphalt mixture and asphalt mortar with a lower number of test results that have similar accuracy to the original master curves and reduce the time and cost of experiments up to 50%.

The authority of a captain is not limited to the technical management of the ship during the voyage and the administrative duties concerning the interaction with the administrative organizations located in commercial ports. The captain has, moreover, a special place arising from his role in the maritime trade scene and his role in managing the ship that allows him to act on behalf of the maritime carriers in the transaction or to take other necessary measures in crew recruitment, ship repair, fulfillment of basic needs, etc. in emergencies where the completion of the voyage is subject to prompt action by the captain. The captain's authority is sometimes deemed to stem from the legitimate and conventional appearance and, consequently, from the reasonable perception created for others. However, he does not have such authority in reality. So, the question arises as to whether the shipowner's defense that captain has acted beyond his authority, if proven, is admissible and precludes the legitimate expectations of the other party to the contract about the owner’s commitment to the consequences of the captain’s acts. In other words, can the captain's authority be extended and can he be considered the shipowner’s agent? In response to this question, legal doctrine and jurisprudence have suggested the apparent agency of the captain in support of third parties in good faith who deal with the captain by trusting in the appearance and considering his authoritativeness. In this study, this type of agency of the captain in his interventions is examined in the domestic and foreign legal system. The results indicate that the apparent agency of the captain is represented mainly in his transactions such as ship sales and mortgages, cargo sales and mortgages, ship rental, crew recruitment, and bill of lading. The apparent agency leads to the liability of the ship owner making him responsible for fulfilling obligations arising from the acts of the apparent agent. Although the advancement of knowledge and the development of communication tools in recent years have made it possible to communicate with the owner and ask him for instructions, the notion of the impossibility of extraordinary intervention of the captain as an apparent agent is hardly acceptable. Accordingly, the legal doctrine today emphasizes the apparent agency of the captain, focusing on his specific role and scope of authority as one of the major bases of the apparent agency. In line with the legal literature, the rulings of foreign courts on a variety of issues uphold the captain's authority to steer ships from the port of loading to the port of discharge. The captain's intervention on behalf of the shipowner is sometimes expanded to the point where court documents are sent to him rather than to the owner or even where he is considered a defendant himself, and sparing him from this status is ruled to be void. Although the legal systems has come to hold the view that the captain lacks the authority to sell the ship, his authority in mortgaging the ship and cargo is a point of contention, each legal system having its own position, with minor disagreements within each system. Following Article 28 of the Iranian Amendment to the Maritime Act approved on 9/18/2012, which has replaced Article 89 of the Iranian Maritime Act, obtaining permission from the shipowner, the sender and the cargo owner is a necessary condition for mortgaging the ship. Although the legislature may appear to want to reduce the captain's authority and, consequently, to strip him of his apparent agency, according to the Paragraph A of the above-mentioned article, the captain is still eligible to receive a loan if necessary funds are not provided by the owner or in necessities when urgent interventions are necessary. Moreover, according to Article 33 of the Amendment to the Maritime Act, which has replaced Article 94 of the Maritime Act, the deficiency of the latter, which failed to determine the legal status of the unjustified sale of the cargo, has been eliminated, and by confirming its validity, the apparent agency of the captain in the sale of cargo has been explicitly acknowledged. This agency can also be sustained in concluding a lease in the event of an emergency. Besides, due to the special place of the ship certificate of registry in establishing the ownership in some legal systems such as the French Law, if the tenant's name is not mentioned in the bill of lading, the owner, being named in the ship certification of registry, is considered responsible for the captain's obligations. The apparent agency of the captain in issuing the bill of lading now enjoys an almost consensual endorsement among legal systems of the world.

Background and Aim: Rotary files may be cause anatomical changes in apical area. The aim of this study was evaluation of maintenance of the canal’s curve using Flex Master and Protaper rotary instruments.Materials and Methods: In this in vitro study, we used 30 mesiobuccal roots of first permanent maxillary molars with a mean length of 18-23 milimeters and a mean curve of 15-40 degrees. Sampling was simple and the specimens were divided into two groups of fifteen. In each group, the canals were prepared by crown down method after the access step. Then they were prepared using Flex master and Protaper according to their company’s instruction. After finishing the preparation steps, hand instrument number 30 was placed in the canals and under the same primary condition we evaluated the final angle by digital radiographic system. For evaluation of the results, we used variance analysis, t test and covariance analysis.Results: The mean angle of apical transportation after using two Flexmaster and Protaper rotary systems was 6/19±3/07 and 5/52±2/87 degree, respectively. The mean apical transporation using the Flexmaster system was more than Protaper system but the difference between them was insignificant (P>0/ 05).Conclusion: Because of using these two rotary systems, we had apical canal transportation. This transportation by using Flexmaster system was more than the Protaper system, but it was not significant.