فصلنامه علوم و فناوری دریا
سال نوزدهم شماره 75 (پاییز 1394)

The paper is based on the analysis of field measurements data of seawater parameters in the southern coasts of the Caspian Sea. The effect of stratification on variation of chemical parameters (active reaction, dissolved oxygen, turbidity, and chlorophyll) and sound speed has been evaluated. The observations were done over fixed stations with a maximum depth of 90 m depth during a marine cruise in the southern coastal waters of the Caspian Sea. During the marine cruise, CTD probe was released into the seawater column from sea surface to the bottom near 90 m depth. The collected data showed formation a seasonal thermal stratification including surface mixed layer, Thermocline and deep water layer in the water column. Chlorophyll levels were measured between 0.1 to 2.9 mg/m3 around 10-15 m depths across the upper boundary of thermocline. The maximum and minimum values of turbidity were 3 and 1.5 NTU and sometimes 5 NTU observed. Measured concentrations of dissolved oxygen were between 4.2-5.6 mg/l. Levels of active reaction were between 8.55 to 8.7 in the water column.

In this paper soft switching technique in DC-DC converters is described. Different circuits with soft switching are shown and then a boost converter which increases the DC input voltage is analysed which has soft switching that enables it to have zero voltage state (ZVS) and zero current state (ZCS). This boost converter uses an auxiliary resonant circuit which is consisted of an active key and some passive elements so the soft switching condition is produced. Then this boost converter is simulated by means of PSIM software and the results are shown which shows the robustness and reliability of this converter.

Until some past decades transportation of cargoes especially for long marine routs faced with many difficulties but with entrance of container, transportation industry was revolutionized, since containerization brought increasing speed, safety and decreasing dependency to human resource. Nevertheless, containers have disadvantages too. Containers are similar to each other and are moving all around the world, which this makes difficult control of containers and their content. But more anxious maker crisis it is that containers should be returned to origin port of cargo after stripping in destination port and often, spend empty return rout and empty container movement means cost. Containers spend about 56 percent of their life time at empty movement and or idle that this fact shows the importance of study about returning empty containers to income cycle. The objective of this research is surveying empty container challenges at Khorramshahr port which has been done by interview with manager, boss and other responsible persons in Khorramshahr container terminal as well as, manager of Khorramshahr agency of container shipping company “Hoopad Darya” and surveying foreign researches of this scope and using of SIPOC diagram and Ordinary Least of Square method.

When goods are imported, all transportation structures separately have this duty to transport it to assigned destination. First shipments arrive by sea, then will transport by rail and then by road transport will distributed in retail. But the main problem today in coastal ports due to the rapid growth of the maritime shipping container in there, is shortage of enough space for storage; also, lack of proper access to the destination of the goods due to the use of traditional methods of transporting, will double the problem. The population of this research includes a number of special areas staff and private sector activists and a number of directors and deputy of ports organization, Data were collected using a questionnaire, and used descriptive and inferential statistics to analyze the data. The purposes of this study are to identify problems of dry ports activity and development and investment on them in IRAN, in order to increase the services as well as reducing the demand of marginal Coastal lands Speculation and increase of foreign investments. We can do something for rectifying the obstacles and problems of dry ports, Using the findings and strategies identified in this study.

Since the Navy is considered as a strategic force in the Islamic Republic of Iran, having a decisive and strategic role in the field is very important and significant. With a view to considering the need to prepare for imbalanced or Heterogeneous battles, new ideas will be important. One of the new ideas that have potential military strategy, is a ship without deck or the float level with the ability to dive into underwater that is called submersible surface ship or SSS. This study suggests the need to consider this type of vessels in various military and civilian aspects, also with the introduction of this type of research is to describe the characteristics of secrecypotential of diving. Then It goes on to discuss the challenges facing in manufacturing it and the proposed construction of a road map has been expressed.

Despite the many applications of wireless sensor networks, due to limited resources such as energy and memory in the sensor, this type of network against malicious attacks are very weak and vulnerable.Therefore, as an effective complement to traditional security methods, management, ensuring a key role in the discovery of suspicious behavior in wireless sensor networks.The main issue is how we can recognize the ideal of nodes in this environment of complex shapes to achieve?In this paper, Markov chain model to calculate the amount of short-term confidence of nodes used and a management system to ensure the reduction of environmental impacts of complex motives have been proposed to compute node status.There's also a new computing model with factors for calculating the long-term reliability suggested that the impact of environmental change in the calculation parameters dropped.Simulation results show that the proposed algorithm can effectively suspicious behavior of wireless sensor network nodes to discover.Can be meaningfully compared to those of packet delivery to provide a more appropriate rate.Finally, better security in wireless sensor networks provide.For TEST!!