Severe saturation of the magnetic core is the most influential factor in ferroresonance that leads to distorted currents and voltages., modeling the nonlinear behavior of the magnetic core is the most important challenge in ferroresonance study. In this paper, finite element method in conjunction with the inverse Jiles-Atherton (JA) hysteresis model of the steel core, is employed for modeling of a single-phase transformer accurately. Then, ferroresonance is studied by inserting different capacitors in series with the unloaded transformer, and the corresponding variation of copper losses and iron losses are obtained and discussed. Ferroresonance affects the shape of the hysteresis loop that necessitates the retuning of the parameters of the JA hysteresis model. The numerical results agree well with the experimental ones.

Residual stresses occur in different processes such as plastic deformation, temperature variation and structural changes. Welding and metal deformation are conventional processes which lead to residual stress. Residual stress plays a key role in the characterization of welded structures, and it has a significant effect on fatigue behavior as well as the lifespan of loaded structures. Therefore, at the first step, measuring residual stress, and in the next level taking action to reduce or eliminate it by usual methods are of extreme significance. In this study, Lamb waves were applied to evaluate the local residual stress in thin steel plates. A two-dimensional hyperelastic nonlinear model on which a Lamb wave propagated was simulated in ABAQUS CAE finite element software. In order to create residual stress, loading was applied to the thin plate either perpendicular or parallel to the wave motion direction. In different frequencies and stresses, the behavior of A0 mode was scrutinized. Results indicated that A0 mode was sensitive to stress changes, and its changes against the residual stress followed a specific trend. In addition, sensitivity to residual stress decreases with increasing frequency. Hence, the frequency of 50 kHz is selected as the optimal frequency in inspecting thin steel plates.

Introduction: Patent ducfus arteriosus (PDA) is the persistence of a normal fetal structure between left pulmonary artery and descending aorta. Persistence of this fetal structure beyond 10 days of life is considered abnormal. In this study we compared M-Mode and Doppler echocardiography in diagnosis of PDA in children at Aliasghar Hospital in Zahedan and Children hospital in Bandar Abbas for one year. methods: We selected 62 patients that were suspicious to have PDA on physical examination. It should be mentioned that we omitted patients with other cgngenital cardiac abnormalities such as truncus arteriosus, ASD, VSD and AZSD. Our patients were below 15years old. Before echocardiography, physical examination, CXR and ECG were done for the patients. Then, they were evluated with both M-Mode and Doppler Echocardiography and finally results were statistically analyzed.Results: Out of 62 patients, 34 were female and 28 were male. 51.6% patients were less than one year old and others were older. 85% of patients had cardiac murmur on physical examination and in 50% of them pulmonary component of second heart sound was increased. Peripheral pounding pulses were present in 85% of patients. In chest X-Ray, 82.3% of patients had increased cardiothoracic ratio and pulmonary vascular markings were increased in 85.5% of them. On ECG, 58.1 % of patients had signs of right and left or bilateral ventricular hypertrophy. Pulmonary hypertension was also seen in 51.6% of patients. PDA was diagnosed with M-Mode echocardiography in 56 patients (90.3 %) and with Doppler echocardiography in 61 patients (98.4%). According to McNemar statistical analysis, there was not an obvious difference between these two. methods of echocardiography in PDA diagnosis (p=0.125).Conclusion: Findings of this study showed that M-Mode and Doppler echocardiography for diagnosis of PDA in children are similar and again attention to M-Mode echocardiography can be helpful in diagnosis of PDA in children especially restless infants and neonates.

The subject of this research is to investigating the advantages of a special stable resonator relative to the flat-symetric stable resonator scheme in high power pumped Nd: YAG lasers. At first a discussion about some convetional resonators used in high power Nd: YAG lasers is presented considering the advantages and shortcomes of each resonator scheme. Then by using distributed refractive power model(DRP), for a typical high power side pumped Nd: YAG laser, and investigating the stability regions, a non symmetric resonator scheme is proposed which gives single transverse mode and demonstrates higher fundamental mode volume (12 times greater) compared with flat-symetric scheme. Also misalignment sensivity of the presented resonator has been studied and compared with flat-symetric resonator, using numerical calculation and simulation with GLAD software. The results of this research revealed that in high level of pumped power, it is also possible to achieve high fundamental mode volume and make the resonator stable due to thermal and mechanical disturbance.

This paper is proposed a novel topology of a single phase grid connected inverter in order to conquest the common mode leakage current. There are many topologies presented so far, But none of them has the efficiency more than 98 percent. In this paper, a modern configuration is presented that, not only delete the common mode leakage current, but also increase the efficiency and power density and is affordable. this inverter consists of 6 switches and 2 diodes that in compare with similar ones, it has less element number. Than the famous topologies like H5, H6 and HERIC, the power loss and voltage stress on switches are decreased. These aspects are appears due to exclusive leg configuration and the placement of switches and diodes. The freewheel path revealed, decoupled DC side from AC side of Inverter which results in disconnecting the common mode current. This issue will modify the network reliability indices and maintain safety standards. Finally the performances of proposed inverter will be compared and evaluated with some available Inverters.

In the last decade, the management of karst water resources has been considered because of its particular role in supplying potable water. In this regard, this research studies the hydrochemical characteristics of springs located at the Ķ ī no anticline. The purpose of this research is to determine the hydraulic relationship and effective factors on the chemical quality of the springs by applying the hydrochemical data and using the main component analysis and hierarchical cluster analysis methods. The results of the analysis of the main components method show that the two components have the most impact on the chemical quality of springs. The first factor consists of magnesium, bicarbonate, sodium, chlorine, Total Dissolved Solids, and electrical conductivity, which is influenced by the quality characteristics of Absard and Mourei springs. The second factor is calcium ions, sulfate, which play the most role in the chemical quality of Susan and Tangsard springs. To investigate the hydraulic connection of the springs, the hierarchical cluster analysis method was used in “ Q-mode” mode. According to the results of this analysis, the data of the Ķ ī no anticline springs are split into two major clusters, which indicate the hydraulic connection between these springs in each cluster. The results of cluster analysis in “ R-mode” mode are also validated by the Q-mode method. The Piper diagram and ion ratios were used to study the chemical processes in the springs. The results of this study showed that the S1 spring with S2 and the S3 spring with S4 have a hydraulic connection.

Health monitoring allows small failures and damages to be identified and fixed before they turn into major and irreparable damages, to prevent loss of life and to make it possible to reinforce or improve it at the lowest cost. Currently, in the field of civil engineering, the health monitoring of structures is done in sensitive structures. One of the parts of the structure that may suffer initial damage before loading and during implementation due to difficulty in implementation is Concrete Filled Tube (CFT)columns.  One of the most likely damages in CFT columns is interface debonding damage. This damage causes the column to become weak and not benefit from the characteristics of steel and concrete together. Accordingly, in the present study, this damage and its severity in seismic (dynamic) parameters have been investigated. The results of the study show that damage causes changes in the mode shape of the structure, and it has caused a 6.38% reduction in the frequency in the first (main) mode of the structure. Also, the damping of the damaged specimen is reduced by approximately 12% compared to the healthy specimen. On the other hand, the results show that the severity of damage is very effective in changing seismic parameters. So that by doubling the damage area, the frequency decreased by approximately 0.35% and reached from 873.27 Hz to 20.870.20 Hz, but the mode shape of damage did not affect the frequency

In recent years several notions of discrete homotopy for graphs have been introduced, including a notion of ×-homotopy due to Dochtermann. In this paper, we define a ×-homotopy fundamental groupoid for graphs, and prove that it is a functorial ×-homotopy invariant for finite graphs. We also introduce tools to compute this fundamental groupoid, including a van Kampen theorem. We conclude with a comparison with previous definitions along these lines, including those built on polyhedral complexes of graph morphisms.