Year:2022 | Volume:26 | Issue:102|Papers Count:6

In this paper, a new circuit is proposed for charge pump for using in delay locked loop, and then simulated in ADS software in 0. 18 μ, m TSMC CMOSRF technology with 1. 8V in transistor level. By using DLL a precise synchronization can be performed through internal and external clocks. In this paper, based on introduced charge pump current mismatching can be solved and so the jitter will be decreased. Finally, 3. 7psec effective jitter in 920MHz for DLL is accrued. In this loop while UP and DN in each duty cycle are proportional to dead zone, not considerable current is flow on the output of CP. Because the UP and DN signals are in current source and by switching each one, probability of following the current to the output will be provided. However, prevents current transition to other switch if turned on.

The occurrence of faults, and consequently the loss of Autonomous Underwater Vehicles (AUV) may create catastrophic outcomes to their owners. Identification of these faults and their classification provide useful information result in the detection of system bottlenecks in the design process. This paper examines the basic faults of AUVs, and studies the failure probability of their components and subsystems. The paper is then builds up the fault tree model of the AUV from its identified faults and structural Topology to highlight its critical paths, critical sub-systems, components importance, and cut-set importance values. The reliability of the AUV is then calculated from its fault tree model in the absence/presence of uncertainty associated with the failure probability of basic events. Fuzzy approach is used for handling the uncertainties. The sensitivity of the vehicle failure to the variation of the failure probability of system components is also calculated by using an innovative way. By the aid of the results of paper, the AUV reliability can be assessed at any arbitrary time frame, the appropriate preventive and predictive maintenance time be determined and by recognition of the AUV failure path, make the system more fault tolerant.

The possibility of using SAR radar images to detect and measure the sea surface roughnesses, which are mainly caused by winds and water turbulence, has been investigated. Various images of Sentinel-1 SAR radar data in C band and the incidence angle of 39. 16 degree were obtained and processed in both VV and VH polarizations to produce images of backscatter coefficient and intensity for Nowshahr maritime region. According to the results, when the average value of backscatter coefficient at VV polarization is 0. 00735, the sea surface roughness in Nowshahr region is low and the wave height is 0. 9 m. But when this coefficient is 0. 034004, the roughness of the sea level is high and the wave height is 2. 7 m. Also, the results confirm that the amounts of backscattering from the sea surface near the shore are higher than the offshore areas in the maritime area of Nowshahr.

Effect of saline and fresh water interference on sound speed variation in the basin of Anzali port has been evaluated. The research is based on the analysis of measured data of various physical parameters of sea water in the vicinity of Anzali port. Also, the effects of saline water of the Caspian Sea and fresh water imported from wetland on the changes in the sound speed in the access channel of Anzali port have been discussed. The data collecting operation was performed by a CTD profiler of the physical parameters of the seawater in fixed stations with a maximum depth of 18 meters in both warm and cold seasons. Results showed that sound speed changed between 1514 and 1511 m/s in the summer. While range of variation in the cold season, was between 1438 (at the surface) and 1454 m/s at 10 m depth. Variation of the sound speed during warm season was affected by water temperature. During cold season, variations of sound speed were under effect of water salinity and, sea saline and wetland fresh water interference. In comparison the results with previous measurements, it is observed that saline and freshwater interference on physical structure of water column and sound speed is considerable in cold season.

The purpose of this study is to study previous and current studies on the subject of green ports and green marine logistics in order to study and rank the factors affecting the transformation of Imam Khomeini port into a green port, which lasted from October 2017 to September 2016. This research is a descriptive-survey research and using a hierarchical analysis model, the factors affecting the transformation of Imam Khomeini port into a green port have been ranked. This study examines the greening of the world's ports and how to implement their proposed solutions in Imam Khomeini port. By conducting this research, it became clear that by using the strategy of involving actors in the maritime industry in a fully operational way and not only in theory in the discussion of port greening, the infrastructure of the greening project in Imam Khomeini port can be done. As a result, among the main factors, internal factors with a relative weight of 0. 771 are recognized as having the first priority. The sub-factor of coastal power supply to vessels with a relative weight of 0. 271 is known as the first priority among the sub-factors of internal and the sub-factor of the speed of vessels with a relative weight of 0. 326 among the sub-factors of externality.

Considering the importance of employing office automation in the productivity of employees of any organization or company, this research was conducted with the aim of investigating the role of automated administrative use in Navy productivity training and employee research in 1396. For this purpose, among 257 people in the statistical population, 154 people were selected using the appropriate sampling method and Cochran formula using the sampling classification method. The research methodology of this research is applied in terms of purpose and in terms of descriptive survey method. The data gathering tool was a questionnaire based on the effectiveness, efficiency and productivity indicators that its content validity was validated and its reliability was confirmed by Cronbach Alpha. Descriptive and inferential statistics were used to analyze the statistical data and to investigate the hypotheses using SPSS software. In the descriptive section, taking into account the frequency of sample characteristics, the central and scattering indices of the variables and in the inferential part The T-student test is used to test the hypotheses. Based on the results, all three hypotheses were confirmed by the researcher. In other words, the results showed that the use of office automation had an impact on the effectiveness, efficiency and effectiveness of the staff of the educational and research departments, and this effect was too "moderate".