—This paper presents modeling and simulation of flexible robot in an underwater environment. The underwater environment completely contrasts with ground or space environment. The robot in an underwater situation is subjected to various dynamic forces like buoyancy forces, hydrostatic and hydrodynamic forces. The underwater robot is modeled as Rayleigh beam. The developed model further allows estimating the deflection of tip in two directions. The complete dynamics of the underwater robot is analyzed, which is the main focus of this investigation. The control of robot trajectory is not discussed in this paper. Simulation is performed using Symbol Shakti software. Keywords—Bond graph modeling, dynamics. modeling, Rayleigh beam, underwater robot. I.

—In this paper, passenger ride comfort issues are studied taking active quarter car model with three degrees of freedom. A hybrid fuzzy – PID controller with coupled rules (HFPIDCR) is designed for vibration control of passenger seat. Three different control strategies are considered. In first case, main suspension is controlled. In second case, passenger seat suspension is controlled. In third case, both main suspension and passenger seat suspensions are controlled. Passenger seat acceleration and displacement results are obtained using bump and sinusoidal type road disturbances. Finally, obtained simulation results of designed uncontrolled and controlled quarter car models are compared and discussed to select best control strategy for achieving high level of passenger ride comfort. Keywords—Active suspension system, HFPIDCR controller, passenger ride comfort, quarter car model. I.

—Conventional seismic designs of quay walls in ports are mostly based on pseudo-static analysis. A more advanced alternative is the Performance-Based Design (PBD) method, which evaluates permanent deformations and amounts of (repairable) damage under seismic loading. The aim of this study is to investigate the suitability of this method for anchored sheet pile quay walls that were not purposely designed for seismic loads. A research methodology is developed in which pseudo-static, permanent displacement and finite element analysis are employed, calibrated with an experimental reference case that considers a typical anchored sheet pile wall. A reduction factor that accounts for deformation behaviour is determined for pseudo-static analysis. A model to apply traditional permanent displacement analysis on anchored sheet pile walls is proposed. Dynamic analysis is successfully carried out. From the research it is concluded that PBD evaluation can effectively be used for seismic analysis and design of this type of structure. Keywords—Anchored sheet pile quay wall, simplified dynamic analysis, performance-based design, pseudo-static analysis I.

Abstract not available.

—An approach to compute optimum seismic design parameters is presented. It is based on the optimization of the expected present value of the total cost, which includes the initial cost of structures as well as the cost due to earthquakes. Different types of seismicity models are considered, including one for characteristic earthquakes. Uncertainties are included in some variables to observe the influence on optimum values. Optimum seismic design coefficients are computed for three different structural types representing high, medium and low rise buildings, located near and far from the seismic sources. Ordinary and important structures are considered in the analysis. The results of optimum values show an important influence of seismicity models as well as of uncertainties on the variables. Keywords—Importance factors, optimum parameters, seismic losses, seismic risk, total cost. I.

—The current-voltage (I-V) characteristics of Pd/n-GaN Schottky barrier were studied at temperatures over room temperature (300-470K). The values of ideality factor (n), zero-bias barrier height (B0), flat barrier height (BF) and series resistance (Rs) obtained from I-V-T measurements were found to be strongly temperature dependent while (Bo) increase, (n), (BF) and (Rs) decrease with increasing temperature. The apparent Richardson constant was found to be 2.1×10-9 Acm-2K-2 and mean barrier height of 0.19 eV. After barrier height inhomogeneities correction, by assuming a Gaussian distribution (GD) of the barrier heights, the Richardson constant and the mean barrier height were obtained as 23 Acm-2K-2 and 1.78eV, respectively. The corrected Richardson constant was very close to theoretical value of 26 Acm-2K-2. Keywords—Electrical properties, Gaussian distribution, Pd-GaN Schottky diodes, thermionic emission. I.

—The present work is dealing with 2% Si-steel alloy. The alloy contains 0.05% C as well as 0.85% Al. The alloy under investigation would be used for electrical transformation purposes. A heating (expansion) – cooling (contraction) dilation investigation was executed to detect the  and transformation temperatures at the inflection points of the dilation curve. On heating, primary was detected at a temperature range between room temperature and 687 o o C. The domain of was detected in the range between 687 C and 746 oC. phase exists in the closed  region at the range between 746 o o C and 1043 C. The domain of  phase appears again at a temperature range between 1043 and 1105 oC, and followed by secondary  at temperature higher than 1105 oC. A physical simulation of thermo-mechanical processing on the as-cast alloy was carried out. The simulation process took into consideration the hot flat rolling pilot plant parameters. The process was executed on the thermo-mechanical simulator (Gleeble 3500). The process was designed to include seven consecutive passes. The 1st pass represents the roughing stage, while the remaining six passes represent finish rolling stage. The whole process was executed at the temperature range from 1100 oC to 900 oC. The amount of strain starts with 23.5% at the roughing pass and decreases continuously to reach 7.5 % at the last finishing pass. The flow curve of the alloy can be abstracted from the stress-strain curves representing simulated passes. It shows alloy hardening from a pass to the other up to pass no. 6, as a result of decreasing the deformation temperature and increasing of cumulative strain. After pass no. 6, the deformation process enhances the dynamic recrystallization phenomena to appear, where the zparameter would be high. Keywords—Si-steel, hot deformability, critical transformation temperature, physical simulation, thermo-mechanical processing, flow curve, dynamic softening I.

Among the alternative energy sources, of particular importance is hydrogen energy, which is likely to address the acute environmental problem of large cities in the near future, in terms of pollution of the environment, first of all, of air pollution from vehicles. Among hydrogen-containing raw materials, which can be used in a fuel component, hydrogen sulphide is of particular importance. It is well-known that the Black Sea the largest basin on the planet by the amounts of hydrogen sulphide dissolved in water. In that regard, the Black Sea is the object of the attention of scientists, since its deep waters contain hydrogen sulphide, hydrosuphide and suphide ions in large quantities. The sources of their origin are gases erupted from the volcanic and geological splits existing at the bottom of the sea, as well as organic substances and products of decomposition of microorganisms brought down by the rivers. In this regard, the Black sea may become a potential source of hydrogen energy, and simultaneously that may improve environmental situation in the Black Sea. The paper analyzes the challenges existing in the use of hydrogen obtained from hydrogen sulphide of the Black Sea, as an alternative fuel in the internal combustion engines of vehicles, as well as the prospects for addressing these challenges.

Abstract not available.