Papers by Keyword: Fe

Abstract: Reinforced concrete (RC) bearing walls are commonly used in building structures to resist axial and lateral loads. Therefore, their ability to withstand loads when exposed to fire is important. The behavior of RC walls under fire exposure is affected by various factors, such as slenderness ratio, concrete strength and composition, and axial load. This paper investigates the effect of slenderness ratio on the structural performance of RC walls subjected to fire. A series of numerical simulations were conducted on RC walls with different slenderness ratios. The simulations are performed on a three-dimensional (3D) finite element (FE) model, after validating its thermal and structural behavior using previously published experimental data. The walls were exposed to standard fire curves (ISO834) on one side. The thermal and structural response of the walls were assessed in terms of axial deformations, out-of-plane deformations, and fire resistance. The results showed that slenderness ratio had a significant influence on the fire behavior of RC walls. The walls with higher slenderness ratios exhibited higher temperature gradients and larger deflections compared to the walls with lower slenderness ratios. Moreover, the fire resistance of the walls was significantly reduced when the slenderness ratio was increased.

Abstract: A modified natural zeolite will be used as a catalyst in the isomerization process of glucose to fructose. It is modified by inserting Fe into its pores with the impregnation method so that the active site of the catalyst is formed as part of the isomerization process. This study aimed to make a catalyst from Fe-impregnated natural zeolite and determine its catalytic performance under various pH, temperature, and isomerization time conditions. The zeolite was activated using 6M H₂SO₄ and 0.5M KMnO₄. The zeolite impregnation process was carried out using 1% (%w/v) FeCl₃.6H₂O solution with a ratio of (1:8) and continued with calcination at 500°C for 4 hours. The Fe-zeolite catalyst was characterized to determine the degree of crystallinity and crystal form, functional groups of its constituent compounds, and surface area. The isomerization process was carried out as a substrate of 10% glucose solution and 1 g of Fe-zeolite catalyst at various temperatures of 40, 50, and 60°C; pH 5, 7, and 9; a sampling time of every 15 minutes for 1 hour. The best fructose yield from the isomerization process was at a reaction temperature of 60°C, pH 5, and 45 min with a yield of 0.837%. It concluded that the Fe-Zeolite catalyst did not give a significant effect on the glucose isomerization process. It is expected that other researchers conduct similar research with different types of metal impregnated to give better results on the glucose isomerization process.

Abstract: DP600 steels are high strength steels used in structural elements of vehicles. However, they can be used in other sectors, but this requires a study in different working conditions, with the help of tools that facilitate the realization of predictions about the mechanical properties of these materials.The "Design Expert" software was used during this research. In it, the combinable input variables are introduced, which in this case are only the size of the pin and the folding angle of the sheet, so that employing simple combinatorial operations tells us how many and which experiments we will have to perform to cover the different possibilities.Simulations have been carried out with the Deform-2D software, applying the finite element method, to know in advance what is going to be the behavior of the metal sheets interacting with the rotating pin, in processes like drawing.

Abstract: The emergence of Dilute Magnetic Semiconductors (DMS) with a potentials for spintronic application have attracted much researches attention, special consideration has been given to ZnO semiconductor material due to its wide band gap of 3.37 eV, large exciting binding energy of 60 meV, moreover, its ferromagnetic behavior at room temperature when doped with transition metals. M_xZn_1-xO (M = Fe or Ni) nanoparticles were synthesized by microwave assisted synthesis method calcined at 600°C. The structural, morphological and magnetic properties of these nanoparticles were studied using X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM) and Vibrating Sample Magnetometer (VSM) respectively. Single phase Wurtzite hexagonal crystal structure was observed for the undoped and Fe doped ZnO nanoparticles with no any impurity, whereas Ni doped ZnO nanoparticles shows the formation of NiO impurities. The magnetic measurement reveals a diamagnetic behavior for the undoped ZnO meanwhile a clear room temperature ferromagnetism was observed for both Fe and Ni doped ZnO. Fe doped ZnO present a high saturation magnetization compared to Ni doped ZnO. However, Ni doped ZnO present high coercivity. The research was confirmed that Fe doped ZnO material will be good material combination for spintronic applications.

Abstract: The effects of welding conditions such as the electrode type and welding current were investigated on the microstructure and joint strength of the resistance weld of A5052 and GA590. The reaction layer formed at the joint interface was inferred to consist of Fe-Al based intermetallic compounds (IMCs) which are FeAl, FeAl₂, Fe₂Al₅ and FeAl₃ by quantitative analysis. Although the thickness of the IMCs layer decreased from the center of the nugget towards the edge of it. When the DR type electrode was used, the cross tensile force became higher than those of the joints formed with the R type one. This is because the thickness of the reaction layer formed at the nugget end of A5052 was thin in the case of the DR type electrode. Also, it was found that cross tensile force increases when the thickness of the reaction layer is thin by multiple regression analysis.

Abstract: The structural-phase state of two-dimensional (d = 1 - 3 ML) coatings before and after annealing and that of Fe nanolayers (d = 4 - 10 ML) were investigated on Si (001)2×1 by electron spectroscopy methods of Auger-electrons and energy losses. The room (30 °С) and lowed (≤ 1250 °С) temperatures of the Si (001) substrate and Fe vapor, respectively, were used during Fe deposition. This study showed the following. An ordered two-dimensional 1×1 phase of Fe stable up to 600 °C and then a Fe₂Si wetting coating stable at 250 °C form near the thickness 1 ML and 3 ML, respectively. Fe deposition on this Fe₂Si coating leads to the one-after-another formation of the Fe₃Si, the Si-in-Fe solution, and then a stable up to 250 °C Fe nanofilm with segregated Si.

Abstract: In this paper, the effect of sintering temperature on the interfacial structure of the composite was investigated and three different formulation groups were used to compare the respective properties. To obtain a composite material with excellent interface, the law between reference number and performance is obtained. Through mixing, molding, sintering, sample preparation, scanning electron microscopic observation, energy spectrometer observation and analysis, the following conclusions can be drawn: As the temperature increases, the density and hardness increase. The sample melts at 1500 °C, and there is no specific data. When the temperature reaches 1450 °C, the density and hardness reach the highest. When the formulation is Fe:Al₂O₃:SiO₂=18:1:1 and the temperature reaches 1450 °C, the properties of the sample materials are optimized. The density is as high as 95% and the hardness reaches 42.9HBW.

Abstract: To explore Fe minerals in Tiga Warna Beach, we investigated to assess the geochemical fraction of Fe in sediment. The samples were leached of Fe using the optimized BCR microwave method. The optimized of BCR microwave method revealed the high accuracy and precision before Fe assessment. The leached of Fe in each of fraction in sediment were measured by AAS. The same patterns of explored Fe in the geochemical fractions from the sediment fraction 1 (mobile fraction) to fraction 3 (oxidizable fraction) as stated nonresistant sediment fractions showed a lower portion of Fe compared with the Fe levels in sediment fraction 4 (residual fraction) or resistant sediment fraction. The Pollution Load Index (PLI) value and the geoaccumulation Index (I-geo) value of sediment samples in blue, green, and red waters indicating that the sediments of Tiga Warna Beach are still natural and has not been categorized as polluted.

Abstract: In this manuscript, the structural properties such as the distance inter-reticular of samples is studied, In the fact, four samples were used symbolized as follows: E tAg(Å), the only difference is the thickness of the Silver buffer layer (tAg= 0, 50, 100 and 150 Å) to find out how the thickness of this layer depends on the structural characteristics of the Iron thin layer, all samples are deposited using molecular beam epitaxy (MBE) at room temperature onto Si (100) substrate. The structural properties of all samples examined using X-ray diffraction method at small and high angles. The small angles X-Ray diffraction curves confirmed to us that there is a clear difference between the surface structure of the samples by varying the number of Kiessig Fringes, Also high angles X-Ray diffraction curves assured us this difference through the clear variation in the angular positions of the peaks of Bragg and the distances inter-reticular values from a sample to the other.

Abstract: Optical reflection spectra in the photon energy range of 1.5-6 eV have been studied after the growth of ultrathin iron films on silicon (001) in the 0-1.2 nm thickness range. It has been noted that the reflection coefficient values vary nonmonotonically in thickness near the limiting energy of 1.5 eV and 6 eV. Moreover, they are abnormally large one at 1.5 eV and small one at 6 eV. It is shown that these phenomena can not be explained by simple models of the formation of a metallic, silicide film or amorphous silicon layer at the interface and correspond to structural-phase transformations in the film and in the substrate interface region.