This contribution evaluates determining factors of Specific Trade Concerns (STCs) raised on Technical Barriers to Trade (TBT) notifications over the period 1995–2011. While multilateral and ...international agreements bind countries concerning the imposition of tariffs on imports, TBTs have been used as trade policy instruments, which conceal the true motivations of governments. The main legitimate reasons behind the imposition of TBTs are to increase environmental qualities and human health, or to improve market efficiencies. However, in addition to these reasons, governments are also in pursuit of protecting their domestic industries. In fact, this contribution analyses how trade protectionist motives and legitimate public policy objectives induce these specific trade measures. Various effective factors of TBT STC notifications are considered in the econometric analysis using fixed effect Poisson estimation as the main technique, and Poisson GMM as robustness specification. Separate estimations on the European Union block in this study points at the determining factors of TBTs harmonized by heterogeneous member states. Results suggest that bilateral trade and tariffs are one of the forces of TBT STC notifications, acknowledging the protectionist behaviour of authorities. Moreover, countries with high quality of humans’ health-related environmental issues, and low environmental vitalities, are more likely to impose new TBTs. Overall, this study confirms the complex nature of TBT STCs affected by economic, technological, institutional, and health and environmental issues.
Ni-based superalloys can withstand a temperature of around 1400 K, while the gas turbine can endure a temperature of around 1800 K thanks to thermal barrier coatings such as Yttria stabilized ...zirconia (YSZ). The present work attempts to introduce a method for modifying commercial Inconel 625 metal powder to enhance the properties of the additively manufactured component for high temperature applications. Inconel 625 was modified by decorating the particles with submicron Yttria-stabilized zirconia (YSZ) particles in order to develop a metal matrix composite material. The goal of this modification was: 1) to enhance the mechanical properties of the Inconel 625 parts after laser powder bed fusion (LPBF) additive manufacturing; 2) to modify the microstructure of the LPBF parts. The influence of LPBF process parameters on surface integrity, microstructure, porosity, and microhardness of the fabricated samples was analyzed for both Inconel 625 and YSZ decorated Inconel samples. Wide ranges of laser power (50–150 W), and volumetric input energy densities (30–270 J/mm3) were examined to fabricate the parts. A Microhardness increase of 30% was observed in laser-fused composite samples after decorating the initial Inconel 625 powder particles with 1 wt% of YSZ. In addition, the microstructural analysis revealed that the addition of YSZ submicron particles stimulates heterogenous nucleation and results in microstructure refinement during LPBF of Inconel 625.
The issue of reliability in power electronic converters (PECs) has received comparatively less attention by researchers. Among PECs, the multilevel inverter is a favourite choice of industry in the ...area of medium-voltage and high-power uses. To study the reliability of PECs, first, the failure rates of elements such as diodes, capacitors, and switches are introduced based on a relevant standard. Then, the reliability indices of two converters, 3-level and 5-level neutral point clamped, are calculated and compared. The results of the reliability study indicate an appropriate converter for sensitive application in industry.
Effect of magnetic field on mechanical properties in Permendur Sheykholeslami, M.; Hojjat, Y.; Ghodsi, M. ...
Materials science & engineering. A, Structural materials : properties, microstructure and processing,
01/2016, Letnik:
651
Journal Article
Recenzirano
Young modulus of magnetostrictive materials such as Permendur are changed by altering the external magnetic field. This phenomenon is called ΔE effect. In this paper, it has been experimentally shown ...that the shear modulus in Permendur is also changed in such a way that the ratio between Young modulus and shear modulus is not constant in different magnetic fields. Thus, Poisson ratio of it is also changed in different magnetic fields. Acoustic pulse–echo method is exploited to measure dependency of these properties to magnetic fields. In this method, longitudinal and shear sound wave velocities in Permendur are measured in different magnetic fields. Using these data, dependency of Young modulus, shear modulus and Poisson ratio on magnetic bias field in Permendur are calculated. Measurements are repeated 30 times in order to study test uncertainty. Changing in Poisson ratio can be interpreted as a result of changing in volume of magnetostrictive materials in different magnetic field (Nagaoka–Honda effect). The amount of this effect in ferromagnetic material is small. Hence, change in Poisson ratio in this material is predicted to be remarkably slight. For instance, based on presented results in Permendur, maximum changing in Poisson ratio is less than 0.014.
Pivot weirs are one of the most important structures for regulating the water level in rivers and canals. These weirs are constructed with one or more gates in a row in the waterways. Changing the ...angle of each gate is done individually with an independent system. Based on available information, the hydraulic performance of this type of weirs (especially in several gates and different angles) in different operational conditions has not been investigated. In present study, pivot weirs with two gates are simulated using Ansys CFX software with the angles of 27.8 to 90 degree and the discharges between 40 to 130 L/s. Further, the importance of the open space between the two adjacent weirs with different angles (lack of retail wall) and its hydraulic behavior have been studied. The model was calibrated based on valid laboratory data and using the K-ϵ turbulence model. Therefore, the weirs with equal angles were studied in the first step. In this case, the effective discharge angle coefficient was studied and its maximum value compared to the vertical angle was obtained 1.076 for the angle of 52°. Furthermore, relationships for discharge coefficient versus upstream water depth were developed. In the next step, the effective length of the crest was found to be increases by 30% under unequal angles operation and the discharge coefficient raised by 1.3 to 2.4 times. Also, it was recognized that, in case of two weirs with unequal angles, about 26% to 69% of the flow passes through the distance between the two weirs. Therefore, the performance of unequal angles operation seems to be more effective in controlling the water level and discharge in different conditions and especially in flood events.
In this study, a pH-sensitive drug delivery system was presented by
o
-phenylenediamine functionalized SBA-15 as a new carrier for controlled release of imatinib mesylate.
O
-phenylenediamine ...functionalized SBA-15 mesoporous silica was synthesized and characterized. Powder X-ray diffraction proved the 2D hexagonal mesostructure with p6mm space group for nanoporous materials. The o-phenylenediamine functionalized SBA-15 showed the BET surface area 265 m
2
g
−1
and pore diameter 5.8 nm, based on adsorption–desorption of N
2
at 77 ºK. The presence of organic groups in the silica framework was demonstrated by FTIR spectrum. Then, the imatinib mesylate was loaded on
o
-phenylenediamine functionalized SBA-15 in saturated drug aqueous solution at ambient temperature for 1 h. According to the observations on drug release in phosphate buffers, the imatinib mesylate release from
o
-phenylenediamine functionalized SBA-15 shows a pH-associated behavior, and the rate of imatinib mesylate release was quicker at lower pH than higher pH. In addition, the imatinib mesylate had a slow release pattern in SBF with a constant rate of approximately 1.4 µg h
−1
after the first hour. The results illustrated that
o
-phenylenediamine functionalized SBA-15 is a suitable option for being employed as a new carrier for controlled release of imatinib mesylate.
The propeller is the predominant propulsion device used in ships. It is difficult to determine the cavitation characteristics and determine the cavitation of a full-size propeller in open water by ...varying the speed and the revolution rate over a range. This paper presents review of erosion resistance materials, cavitation and effects of energy saving on the shape of current after propeller, on Waginigen B Series ship propeller type in open water system. Experiments are very expensive and time consuming, so the present paper deals with a complete computational solution for the flow using Ansys Fluent 14.0 software. When the operating pressure was lowered below the vapor pressure of surrounding liquid it simulates cavitation conditions. In the present work, Ansys Fluent 14.0 software is also used to solve advanced phenomena like cavitation of propeller. The simulation results of cavitation and open water characteristics of propeller are compared with the result of cavitation around marine propellers with energy saving devices.
Catwalks are one of main components of each offshore complex. Their most important functionality is to provide connection between different parts such as the jackets and flare or between two ...neighboring jackets. Due to the catastrophic environmental and financial losses as well as the more importantly, loss of lives in case of the failure of an offshore platform and/or one of its elements, damage detection in this type of offshore structure is of a great importance. Such a concise damage identification can reduce the negative impacts of the failure of the structure on the marine habitat. Modal strain energy method is one of the most promising damage identifying methods which is based on variations in the dynamic characteristics of the structure. In this paper, a sensitivity-based modal strain energy damage identification technique is used to localize and quantify the assumed damages in an offshore catwalk structure. The finite element model of the structure is validated by comparing the outcomes of numerical and experimental modal analysis performed on the structure. This study shows that the implemented damage identification technique can be used to detect damages in real offshore truss structures with numerous members.
