Papers by Keyword: Superstructure

Abstract: In the Li₂O-M₂O₅-TiO₂ system, Li_1+x-yM_1-x-3yTi_x+4yO₃ (M = Nb, or Ta, 0.06 ≤ x ≤ 0.33, 0 ≤ y ≤ 0.175 (LMT) forms a superstructure, known as smart material. The superstructure is formed by periodical insertion of a corundum-type intergrowth layer of [Ti₂O₃]²⁺ in a matrix having a trigonal structure during the grain growth. To apply this unique structure as a host material of phosphor, new phosphors doped with Mn⁴⁺ ion with a red emission colour, which had a broad peak around 685 nm excited by 493 nm. In order to improve the PL intensity, we investigated the compositions, Mn⁴⁺ ratio and crystal structure. Results showed that PL intensity was closely related to Mn⁴⁺ ratio and its crystal structure.

Abstract: We successfully synthesized Li_1+x-yM_1-x-3yTi_x+4yO₃ solid solutions (M = Nb or Ta, LMT, 0.07 ≤ x ≤ 0.33, 0 ≤ y ≤ 0.175) that have a superstructure. The materials formed a superstructure known as the M-phase, which is formed by the periodical insertion of an intergrowth layer in a matrix having a trigonal structure. The homogeneous and periodical structure of M-phase in LNT needed to sinter at 1393 K for 40 h-200 h using a conventional electric furnace. In order to form the homogeneous intergrowth layers rapidly, millimeter-wave or air-pressure control atmos furnaces were also used as smart processing techniques. We concluded that atomic diffusion was promoted in the useful reaction-fields: millimeter-wave radiation or high oxygen pressure.

Abstract: One of the owner’s common problem before executing construction projects is the complexity in estimating the project cost in an early stage. Inaccurate cost estimation will force the owner to make further arrangement to the project budget. This study aims to develop an initial cost estimation model for superstructures of Precast I-girder Bridge. Cost estimation model was developed based on thirteen data of detail engineering design of I-girder bridge in Daerah Istimewa Yogyakarta (DIY). Factors influencing the cost of the superstructures of the I-girder bridge were identified. Bridge span and width, the size of the sidewalk, and railing’s type are considered as variables affecting the cost of superstructures. These variables are then arranged into two different analysis Multiple Linear Regression (MLR) analysis and Artificial Neural Network (ANN), in order to obtain the best estimation model. The results of the analysis showed that bridge span and width were the significant factors influencing cost. The correlation value of bridge span is 89.0%, bridge width is 74.2%, the size of the sidewalk is 66.1%, and railing’s type is 46.1% as identified factors that affect the cost of the superstructure. A comparative model of two approaches shows that the ANN has better accuracy than that of MLR, although the difference was not significant.

Abstract: This paper wish to make a presentation of the possibility to use glass and polyester fiber waste in making highway cold recycling better, easier and cheaper. For this purpose we have studied the influence of the fibers (glass and polyester) on some experimental sectors, from our country, Sălaj district, Transylvania. Glass and polyester fiber waste can be used like disperse reinforcing materials in highway superstructures in so called cold recycling technology. The fibers are throughput in the matrix for better physical and mechanical properties of the final product. This technique will give better highway surface, cheaper costs per rehabilitated kilometer and diminution of the waste that some industries are making.Most studies from this scientific sector are gravening above the realization of brand new superstructures ignoring the possibility to recycling the existing layers with or without other materials in addition. The period that we are passing is one characterized by intense preoccupations oriented on the economically aspect, much more over the big investments like are highways and bridges - were the cheaper solution is the winner.There are some problems in spreading and dosage of the fibers in the system to ensure the reinforcing function. For the recycled complex (aggregates, bitumen, cement, water and fibers) we will use the generically denomination of matrix. The improvement of physical, mechanical and chemical properties of the matrix constitutes problems that are hard to solve in a very short time. Regarding the fibers the biggest problem is the dosage and homogenization in the structure. To attend this purpose fiber need to have the correct length ant the correct spread in the matrix.We had make a bibliography documentation, that encourage us to believe that using some alternative solutions will obtain very good results also in our country, that have the well-known problems regarding its highway infrastructure.

Abstract: Phase composition and γ′-phase morphology of a superalloy on based N I-Al doped by high-melting elements in it after ordering annealing hawe been studied by TEM, SEM and electron microdiffraction methods. It is revealed that after annealing superalloy comprises mainly γ′-phase (∼90%). The structure, distribution and morphology of γ′-phase is determined.

Abstract: Implant supported prostheses have led to drastic improvements in edentulous patients ‘standard of living and quality of life compared with treatment with conventional dentures. However the solution with four implants connected with a bar and a prosthetic superstructure seems to gain more trust.

Abstract: In the Li2O-Nb2O5-TiO2 system, Li1+x-yNb1-x-3yTix+4yO3 (0.06  x  0.33, 0  y  0.09) (LNT) forms with a superstructure, which is the so-called M-phase. In this work, as a first step toward application of the unique qualities of an electro-ceramic with an anisotropic structure, we prepared an oriented LNT balk ceramic by slip casting in a strong magnetic field of 12 T. The direction of the magnetic field was parallel to the casting direction. The compact was densified by cold isostatic pressing and then heated at 1373 K. The obtained specimen was analyzed by X-ray diffraction, scanning electron microscope, and transmission electron microscope. Consequently, the c-axis of the LNT powders was aligned parallel to the magnetic field and a high orientation degree was achieved in a strong magnetic field of 12 T

Abstract: The superstructure and foundation of highrise are in a complete system of interaction. Taking the case of project, by comparatively analyzing the computed value which is calculated by applying the theory of interaction between superstructure and foundation and the measured value ,we find that the computed value neatly dovetails with the measured value.

Abstract: The risk of injuries and fatalities is severe when bus superstructure fails during rollover accidents. This study deals with two stages of analyses which are superstructure strength having rollover analysis and occupants kinematic analysis. The validation process by correlating the strain results obtained from simple box rollover and simulation process done. The inputs from validation process had been used for full-scale bus superstructure rollover. A complete bus structure was developed and simulation was done according to the United Nation Economic Commission of Europe (UNECE) regulation 66 by utilizing finite element analysis software. Injury to occupant at various locations was studied as well as comparison study between belt occupant and unbelted occupants by using the Mathematical Dynamic Model (MADYMO) software. Analysis suggested that superstructure strength and occupant kinematics consideration can reduce fatality and serious injury in bus rollover accident.

Abstract: Alloys of Cu-Pt [1] are of interest for research, since the phase transitions "order - disorder" at different concentrations of components form several types of superstructures. In the alloy Cu₃Pt the ordering L1₂ superstructure formed on the basis of fcc lattice. In the ordering of the fcc lattice of the disordered solid solution the equiatomic composition transformed into the L1₁ superstructure with an rhombohedral crystal lattice (a state with an L1₁, whose angles α, β, and γ are other than π/2). A CuPt₃ in an ordered state has an L1₃ superstructure (a state with an L1₃, whose angles α, β, and γ are other than π/2). A possible existence of an ordered phase containing 20 at.% Pt was reported in the literature [2], which corresponds to the composition of Cu₄Pt (type of superstructure was not defined). In other sources, an occurrence of an ordered compound, Cu₇Pt, was predicted, containing 12.5 at.% Pt [3]. Computer experiments performed on the Monte Carlo method, showed that the alloys of the Cu - Pt different composition components undergo phase transformations "disorder - order" from the FCC to the structures of different symmetry [4,11]. This paper presents the results of a study of the structural transformations in the alloys Cu₃Pt, CuPt, CuPt₃ (superstructure L1₂, L1₁, L1₃), containing shear antiphase boundaries (APB) in the planes {111}.