1. |
- Korojy, Bahman, et al.
(författare)
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Microsegregation and Solidification Shrinkage of Copper-Lead Base Alloys
- 2009
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Ingår i: Advances in Materials Science and Engineering. - : Hindawi Publishing Corporation. - 1687-6822 .- 1687-8434 .- 1687-8442.
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Tidskriftsartikel (refereegranskat)abstract
- Microsegregation and solidification shrinkage were studied on copper-lead base alloys. A series of solidification experiments was performed, using differential thermal analysis (DTA) to evaluate the solidification process. The chemical compositions of the different phases were measured via energy dispersive X-ray spectroscopy (EDS) for the Cu-Sn-Pb and the Cu-Sn-Zn-Pb systems. The results were compared with the calculated data according to Scheil's equation. The volume change during solidification was measured for the Cu-Pb and the Cu-Sn-Pb systems using a dilatometer that was developed to investigate the melting and solidification processes. A shrinkage model was used to explain the volume change during solidification. The theoretical model agreed reasonably well with the experimental results. The deviation appears to depend on the formation of lattice defects during the solidification process and consequently on the condensation of those defects at the end of the solidification process. The formation of lattice defects was supported by quenching experiments, giving a larger fraction of solid than expected from the equilibrium calculation.
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2. |
- Sadeghi, Mohammad, et al.
(författare)
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Experimental and Theoretical Studies on the Effect of Die Temperature on the Quality of the Products in High-Pressure Die-Casting Process
- 2012
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Ingår i: Advances in Materials Science and Engineering. - : Hindawi Limited. - 1687-6822 .- 1687-8434 .- 1687-8442. ; :434605
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Tidskriftsartikel (refereegranskat)abstract
- Die temperature in high-pressure die casting of A380 alloy is optimized by experimental observation and numerical simulation. Ladder frame (one part of the new motor EF7) with a very complicated geometry was chosen as an experimental sample. Die temperature and melt temperature were examined to produce a sound part. Die temperatures at the initial step and the final filling positions were measured and the difference between these values was calculated. ProCAST software was used to simulate the fluid flow and solidification step of the part, and the results were verified by experimental measurements. It is shown that the proper die temperature for this alloy is above 200 degrees C.
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3. |
- Almusaed, Amjad, 1967-, et al.
(författare)
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A Research on the Biophilic Concept upon School's Design from Hot Climate : A Case Study from Iraq
- 2022
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Ingår i: Advances in Materials Science and Engineering. - UK : Hindawi Publishing Corporation. - 1687-8434 .- 1687-8442.
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Tidskriftsartikel (refereegranskat)abstract
- In recent years, there have been solid global trends and severe attempts by ministries of education in the world to improve the reality of educational institutions and schools through the design and construction of schools and educational systems that meet the requirements of the age by applying the concepts of sustainable and effective systems to the new generation. They called for a promising future and hence the need to activate the applications of the biophilic schools. The theme of the biophilic schools is closely related to the concept of sustainable environmental structures that deal with the surrounding natural environment with intimacy, which is one of the most important new methods of design and construction at present, where ecological challenges are powerfully evoked in the making of their design decisions. Biophilic schools are an essential part of a new concept that wants to design revolutionary educational systems with new economic outputs that are valuable but do not depart from the idea of sustainable schools in general. It represents an expression given to schools designed to be environmentally sensitive and healthy for their occupants and educational systems based on experience, humanity, and attraction. Indeed, many architects have begun to explore and develop new architectural designs linked with the concepts of biophilic schools. Through the researchers' awareness of the negative circumstance experienced by school buildings in Iraq and by investing in the recommendations of an applied field research, it was reached to crystallize the research problem represented in the obstacles that schools suffer from, which calls for the search for developmental solutions for an efficient educational environment, and in order to reach this goal, by informing researchers about new global experiences in this field, the research presented its hypothesis in choosing the model of biophilic schools that exist in many countries in the world, because of what it can provide from successful and fruitful educational and urban components. The researchers reached many conclusions and recommendations aimed at applying the research hypothesis and achieving its goals.
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4. |
- Cwirzen, Andrzej, et al.
(författare)
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Interaction of Magnesia with Limestone-Metakaolin-Calcium Hydroxide Ternary Alkali-Activated Systems
- 2018
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Ingår i: Advances in Materials Science and Engineering. - : Hindawi Publishing Corporation. - 1687-8434 .- 1687-8442. ; 2018
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Tidskriftsartikel (refereegranskat)abstract
- The effect of magnesia on ternary systems composed of limestone, metakaolin and calcium hydroxide, alkali activated with sodium silicate, sodium hydroxide, and sodium sulphate was studied by determination of the compressive strength, X-ray powder diffraction (XRD), thermogravimetry (TG), and scanning electron microscope (SEM). Pastes activated with sodium silicate and sodium sulphate showed strength regression caused by a formation of an unstable prone to cracking geopolymer gel. The presence of magnesia in sodium hydroxide-activated system hindered this trend by promoting a formation of more stable crystalline phases intermixed with brucide. In general, magnesia densified the binder matrix by promoting a formation of amorphous phases while sodium hydroxide produced the most porous microstructure containing high amount of crystalline phases.
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5. |
- Dash, Saroj Prasad, 1975, et al.
(författare)
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Tunnel Contacts for Spin Injection into Silicon: The Si-Co Interface with and without a MgO Tunnel Barrier - A Study by High-Resolution Rutherford Backscattering
- 2012
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Ingår i: Advances in Materials Science and Engineering. - : Hindawi Limited. - 1687-8442 .- 1687-8434. ; 2012, s. Art. no. 902649-
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Forskningsöversikt (refereegranskat)abstract
- In order to obtain high spin injection efficiency, a ferromagnet-semiconducor Schottky contact must be of high crystalline quality. This is particularly important in the case of ferromagnet-silicon interfaces, since these elements tend to mix and form silicides. In this study Co-Si (100) interfaces were prepared in three different ways: by evaporation at room temperature, low temperature (-60°C), and with Sb as surfactant, and their interface structures were analyzed by high-resolution RBS (HRBS). In all cases more or less strong in-diffusion of Co with subsequent silicide formation was observed. In order to prevent the mixing of Co and Si, ultra thin MgO tunnel barriers were introduced in-between them. In situ HRBS characterization confirms that the MgO films were very uniform and prevented the mixing of the Si substrate with deposited Co and Fe films effectively, even at 450°C.
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6. |
- Grandfield, Kathryn, et al.
(författare)
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Focused ion beam in the study of biomaterials and biological matter
- 2012
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Ingår i: Advances in Materials Science and Engineering. - : Hindawi Limited. - 1687-8434 .- 1687-8442. ; , s. 841961-
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Tidskriftsartikel (refereegranskat)abstract
- The application of focused ion beam (FIB) techniques in the life sciences has progressed by leaps and bounds over the past decade. A once dedicated ion beam instrument, the focused ion beam today is generally coupled with a plethora of complementary tools such as dual-beam scanning electron microscopy (SEM), environmental SEM, energy dispersive X-ray spectroscopy (EDX), or cryogenic possibilities. All of these additions have contributed to the advancement of focused ion beam use in the study of biomaterials and biological matter. Biomaterials, cells, and their interfaces can be routinely imaged, analyzed, or prepared for techniques such as transmission electron microscopy (TEM) with this comprehensive tool. Herein, we review the uses, advances, and challenges associated with the application of FIB techniques to the life sciences, with particular emphasis on TEM preparation of biomaterials, biological matter, and their interfaces using FIB.
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7. |
- Hemmilä, Venla, 1987-, et al.
(författare)
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Evaluation of dynamic microchamber as a quick factory formaldehyde emission control method for industrial particleboards
- 2018
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Ingår i: Advances in Materials Science and Engineering. - : Hindawi Publishing Corporation. - 1687-8434 .- 1687-8442.
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Tidskriftsartikel (refereegranskat)abstract
- The most common formaldehyde control method for wood panels in Europe, the perforator method, measures formaldehyde content, while most of the legal requirements in the world are based on emissions. Chamber methods typically used for emission measurements require too much time to reach steady state for factory quality control. The aim of this study was therefore to investigate whether emission values of particleboards measured one day after production would be usable for quality control purposes. The correlation between 1-day and 7-day emission values was determined using a dynamic microchamber (DMC). Three industrial board types that differed in density and emission levels were used for the evaluation. The online emission measuring equipment Aero-laser AL4021 connected to the 1 m3 chamber was used to gain further information on the emission reduction behaviour of the different board types. Only the two particleboard types with higher densities showed good correlation between the 1-day and 7-day emissions. The overall results suggested that 1-day emission values can be used for factory quality control purposes; however, if the initial 1-day values are above the permitted level, extensive evaluation for each individual board type needs to be performed
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8. |
- Hrubovcakova, Monika, et al.
(författare)
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Parameters Controlling the Oxide Reduction during Sintering of Chromium Prealloyed Steel
- 2013
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Ingår i: Advances in Materials Science and Engineering. - : Hindawi Limited. - 1687-8442 .- 1687-8434. ; 2013
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Tidskriftsartikel (refereegranskat)abstract
- Temperature intervals of oxide reduction processes during sintering of the Fe-3%Cr-0.5% Mo prealloyed powder using continuous monitoring of processing-exhaust gas composition (CO, CO2, and H2O) were identified and interpreted in relation to density (6.5-7.4 g/cm(3)), sintering temperature (1120 and 1200 degrees C), heating and cooling rates (10 and 50 degrees C/min), carbon addition (0.5/0.6/0.8%), type (10% H-2-N-2, N-2), and purity (5.0 and 6.0) of the sintering atmosphere. The progress in reduction processes was evaluated by oxygen and carbon contents in sintered material and fracture strength values as well. Higher sintering temperature (1200 degrees C) and density
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9. |
- Hu, Chichun, et al.
(författare)
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Experimental Study of Dowel Bar Alternatives Based on Similarity Model Test
- 2017
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Ingår i: Advances in Materials Science and Engineering. - : Hindawi Limited. - 1687-8434 .- 1687-8442.
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Tidskriftsartikel (refereegranskat)abstract
- In this study, a small-scaled accelerated loading test based on similarity theory and Accelerated Pavement Analyzer was developed to evaluate dowel bars with different materials and cross-sections. Jointed concrete specimen consisting of one dowel was designed as scaled model for the test, and each specimen was subjected to 864 thousand loading cycles. Deflections between jointed slabs were measured with dial indicators, and strains of the dowel bars were monitored with strain gauges. The load transfer efficiency, differential deflection, and dowel-concrete bearing stress for each case were calculated from these measurements. The test results indicated that the effect of the dowel modulus on load transfer efficiency can be characterized based on the similarity model test developed in the study. Moreover, round steel dowel was found to have similar performance to larger FRP dowel, and elliptical dowel can be preferentially considered in practice.
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10. |
- Janis, Diana, et al.
(författare)
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Application of Different Extraction Methods for Investigation of Nonmetallic Inclusions and Clusters in Steels and Alloys
- 2014
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Ingår i: Advances in Materials Science and Engineering. - : Hindawi Limited. - 1687-8434 .- 1687-8442. ; 2014, s. 210486-
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Tidskriftsartikel (refereegranskat)abstract
- The characterization of nonmetallic inclusions is of importance for the production of clean steel in order to improve the mechanical properties. In this respect, a three-dimensional (3D) investigation is considered to be useful for an accurate evaluation of size, number, morphology of inclusions, and elementary distribution in each inclusion particle. In this study, the application of various extraction methods (chemical extraction/etching by acid or halogen-alcohol solutions, electrolysis, sputtering with glow discharge, and so on) for 3D estimation of nonmetallic Al2O3 inclusions and clusters in high-alloyed steels was examined and discussed using an Fe-10 mass% Ni alloy and an 18/8 stainless steel deoxidized with Al. Advantages and limitations of different extraction methods for 3D investigations of inclusions and clusters were discussed in comparison to conventional two-dimensional (2D) observations on a polished cross section of metal samples.
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