Advances in Materials Science and Engineering http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2016 , Hindawi Publishing Corporation . All rights reserved. Research on Properties of Foamed Concrete Reinforced with Small Sized Glazed Hollow Beads Sat, 30 Apr 2016 14:35:16 +0000 http://www.hindawi.com/journals/amse/2016/5820870/ Foamed concrete (400 kg/m3) was prepared through a physical foaming method using ordinary Portland cement (42.5R), vegetable protein foaming agent, fly ash, and glazed hollow beads (GHB, K46) as raw materials. The performance of cement paste as well as the structure and distribution of air voids was characterized by rheometry, SEM, and XRD analyses with imaging software. The effects of GHBs on the compressive strength and thermal conductivity of the foamed concrete sample were also explored. Results show that the proportion of 50–400 μm air voids, average air-void diameter, 28 d compressive strength, and thermal conductivity of the test sample mixed with 2.4 wt% GHBs are 94.44%, 182.10 μm, 2.39 MPa, and 0.0936 w/(m·k), respectively. Excessive amount of GHBs (>2.4 wt%) increases the amount of air voids with diameter smaller than 50 μm in the hardened foamed concrete as well as the degree of open porosity. Moreover, the proportion of 50–400 μm air voids, average air-void diameter, 28 d compressive strength, and thermal conductivity of the sample mixed with 4.0 wt% GHBs are 88.54%, 140.50 μm, 2.05 MPa, and 0.0907 w/(m·k), respectively. Chi Hu, Hui Li, Zhongwei Liu, and Qingyuan Wang Copyright © 2016 Chi Hu et al. All rights reserved. A Novel Inward Gradient Self-Lubrication Layer with Soft Alloys and Its Lubricating Mechanism Sat, 30 Apr 2016 13:53:31 +0000 http://www.hindawi.com/journals/amse/2016/9286450/ A novel ceramic composite inward gradient distribution layer has been developed. The layer is a lubricating layer in which soft-metal lubricants are compounded into the ceramic matrix by high frequency induction infiltrating method. The design of the layer and its lubricating mechanism are investigated in the paper. The results show that the property of the layer greatly depends on the wetting angle of the soft-metal lubricants on the matrix and the proportion of Ag, Cu, Sn, and Pb as well as the infiltrating parameters. Based on a lot of experiments, a novel inward gradient layer with Pb28Sn19Ag6Cu has been developed. The layer has an excellent lubricating property (friction coefficient about 0.2~0.3 at 600°C). The research reveals the lubricating mechanism, observing the phenomenon that the soft-metal in the matrix diffuses out of the frictional surface, and measures the lubricating film thickness as about 20 μm on the worn surface. Songshan Yan, Ling Qin, Rui Hu, and Zuomin Liu Copyright © 2016 Songshan Yan et al. All rights reserved. Inspection and Numerical Analysis of an Ottoman Railway Bridge in Jordan Sat, 30 Apr 2016 13:50:17 +0000 http://www.hindawi.com/journals/amse/2016/9039483/ The construction of bridges represents a big challenge, since they require enormous economic effort and specialized technical skills. Bridges were historically important as they help connecting people and thus diffusing cultures, sharing ideas, and providing the backbone of transportation networks. This study focuses on the inspection and structural analysis of a 20th-century Ottoman railway stone arched bridge located on the Hejaz railway network in Jordan. The bridge has a very important cultural heritage value which stems from its history. The bridge stone material was cut and tested to determine its strength, in order to be used in the analysis. The structural analysis was carried out to assess the structural condition of the bridge and its suitability for reuse. The study includes static analysis under gravity loads and seismic analysis under earthquake loads. Despite the existence of deterioration in the bridge body construction materials due to a combination of human and natural factors, the analysis results proved enough structural capability to sustain the imposed gravity loads, but not a strong earthquake. Amin H. Almasri and Qusai Fandi Al-Waked Copyright © 2016 Amin H. Almasri and Qusai Fandi Al-Waked. All rights reserved. Role of Dielectric Constant on Ion Transport: Reformulated Arrhenius Equation Thu, 28 Apr 2016 13:29:47 +0000 http://www.hindawi.com/journals/amse/2016/2527013/ Solid and nanocomposite polymer electrolytes based on chitosan have been prepared by solution cast technique. The XRD results reveal the occurrence of complexation between chitosan (CS) and the LiTf salt. The deconvolution of the diffractogram of nanocomposite solid polymer electrolytes demonstrates the increase of amorphous domain with increasing alumina content up to 4 wt.%. Further incorporation of alumina nanoparticles (6 to 10 wt.% Al2O3) results in crystallinity increase (large crystallite size). The morphological (SEM and EDX) analysis well supported the XRD results. Similar trends of DC conductivity and dielectric constant with Al2O3 concentration were explained. The TEM images were used to explain the phenomena of space charge and blocking effects. The reformulated Arrhenius equation () was proposed from the smooth exponential behavior of DC conductivity versus dielectric constant at different temperatures. The more linear behavior of DC conductivity versus reveals the crucial role of dielectric constant in Arrhenius equation. The drawbacks of Arrhenius equation can be understood from the less linear behavior of DC conductivity versus . The relaxation processes have been interpreted in terms of Argand plots. Shujahadeen B. Aziz Copyright © 2016 Shujahadeen B. Aziz. All rights reserved. Effect of the Yield Criterion of Matrix on the Brittle Fracture of Fibres in Uniaxial Tension of Composites Thu, 28 Apr 2016 11:47:53 +0000 http://www.hindawi.com/journals/amse/2016/3746161/ This paper examines the effect of the yield criterion of the matrix on brittle fracture of the fibre in continuous fibre reinforced metal matrix composites subjected to tension in the direction parallel to the fibres. It is assumed that the matrix obeys quite a general isotropic yield criterion. An approximate approach to predicting the tensile load at which the fibre breaks previously proposed in the literature is adopted. It is shown that this tensile load is practically independent of the yield criterion of the matrix. This is a great advantage for engineering applications since an analytic solution is available in the case of Tresca yield criterion. This solution can be used for a wide range of matrix materials with no loss of the accuracy of the prediction of the tensile load at which the fibre breaks. Sergei Alexandrov, Yaroslav Erisov, and Fedor Grechnikov Copyright © 2016 Sergei Alexandrov et al. All rights reserved. Study on Tensile Damage Constitutive Model for Multiscale Polypropylene Fiber Concrete Tue, 26 Apr 2016 16:40:09 +0000 http://www.hindawi.com/journals/amse/2016/9168984/ Polypropylene fibers perform well in roughness enhancement and corrosion resistance. They can dissipate energy when cracks occur in concrete. Furthermore, they can improve the concrete tensile properties by synergistic work with it. To study the tensile properties of the multiscale polypropylene concrete, uniaxial tensile strength of 18 fiber reinforced and 3 plain concrete specimens was experimentally tested using the paste steel method. The test results indicate that both the strength and the peak strain can be substantially improved. Based on the results, a tensile damage constitutive model was proposed and implemented into FLAC3D for numerical experimentation. The numerical results are consistent with the experimental observations in general and some discrepancies are discussed. Ninghui Liang, Jifei Dai, and Xinrong Liu Copyright © 2016 Ninghui Liang et al. All rights reserved. Enhanced Thermal Performance and Impact Strength of UHMWPE/Recycled-PA6 Blends Synthesized via a Melting Extrusion Route Tue, 26 Apr 2016 08:21:18 +0000 http://www.hindawi.com/journals/amse/2016/8089525/ The blends of ultra-high molecular weight polyethylene (UHMWPE) and recycled-polyamide 6 (R-PA6) were prepared via a melting extrusion route using high-density polyethylene-graft-maleic anhydride (HDPE-g-MAH) as the compatibilizer. The morphologies and distributions of the chemical components of the blends were characterized by scanning electron microscopy and synchrotron Fourier transform infrared microspectroscopy. The effects of R-PA6 content on the Vicat softening temperature (VST), heat distortion temperature (HDT), and impact strength of the blends were studied. Remarkably, in comparison with those of UHMWPE, the VST and HDT of UHMWPE/R-PA6 blends with 44 wt% R-PA6 were increased to 165.1 and 98.4°C, respectively, and the Charpy impact strength and Izod impact strength of the blends were enhanced to 33.9 and 16.2 kJ/m2, respectively. In addition, it was found that the blending system containing 44 wt% R-PA6 and 48 wt% UHMWPE exhibited the best compatibility when it was prepared using 8 wt% HDPE-g-MAH. The distribution of the phases of UHMWPE and R-PA6 was uniform, and no obvious phase separation was observed in the blends. Xiuying Yang, Junye Cheng, Guangping Zheng, and Deqing Zhang Copyright © 2016 Xiuying Yang et al. All rights reserved. Synthesis and Characterization of Pumice-Supported nZVI for Removal of Copper from Waters Thu, 21 Apr 2016 09:19:45 +0000 http://www.hindawi.com/journals/amse/2016/4372136/ The target of this work was to study the synthesis and characterization of pumice-supported nanoscale zero-valent iron (nZVI) and the effectiveness of nZVI coated pumice to remove copper from water. The impacts of pumice dose, pumice surface chemistry, pH, and water source on copper removal were studied. Natural pumice particles were used as granular support media and coated with nZVI. Results of nZVI coated pumice characterization showed nZVI coated successfully on pumice surface being proved with characterization methods such as SEM-EDS, XPS, and XRF. nZVI coating overwhelmed the surface chemistry properties of the underlying pumice particles. Higher surface areas and more iron content were obtained in nZVI coated pumice. nZVI coating significantly increased copper uptake compared to uncoated particles. High removal capacity has been observed for all tested pH values. Control experiments indicated that nZVI bound on pumice surfaces is stable at pH values of typical natural waters. The nZVI coated pumice was found to be effective in removing copper from waters having a wide range of specific UV absorbance (SUVA) values. Overall, the results indicated that nZVI coated pumice particles are maybe alternative adsorbents to remove copper. Bilgehan Ilker Harman and Mesut Genisoglu Copyright © 2016 Bilgehan Ilker Harman and Mesut Genisoglu. All rights reserved. Rapid Determination of the S-N Curve for Steel by means of the Thermographic Method Wed, 20 Apr 2016 14:24:36 +0000 http://www.hindawi.com/journals/amse/2016/4134021/ The paper presents a thermographic method of accelerated determination of the S-N curve. In the presented method, the S-N curve was developed based on energy-related parameter with the assumption of its dependency on the stress amplitude. The tests made on C45 steel and X5CrNi18-10 steel under reversed bending revealed that the S-N curve obtained by accelerated thermographic method fits inside the 95% confidence interval for the S-N curve obtained from the full test. Adam Lipski Copyright © 2016 Adam Lipski. All rights reserved. Thermal Cracking Analysis during Pipe Cooling of Mass Concrete Using Particle Flow Code Wed, 20 Apr 2016 12:26:48 +0000 http://www.hindawi.com/journals/amse/2016/5976862/ Pipe cooling systems are among the potentially effective measures to control the temperature of mass concrete. However, if not properly controlled, thermal cracking in concrete, especially near water pipes, might occur, as experienced in many mass concrete structures. In this paper, a new numerical approach to simulate thermal cracking based on particle flow code is used to shed more light onto the process of thermal crack propagation and the effect of thermal cracks on thermal fields. Key details of the simulation, including the procedure of obtaining thermal and mechanical properties of particles, are presented. Importantly, a heat flow boundary based on an analytical solution is proposed and used in particle flow code in two dimensions to simulate the effect of pipe cooling. The simulation results are in good agreement with the monitored temperature data and observations on cored specimens from a real concrete gravity dam, giving confidence to the appropriateness of the adopted simulation. The simulated results also clearly demonstrate why thermal cracks occur and how they propagate, as well as the influence of such cracks on thermal fields. Liang Li, Xinghong Liu, Vinh T. N. Dao, and Yonggang Cheng Copyright © 2016 Liang Li et al. All rights reserved. Influence of Soda Pulping Variables on Properties of Pineapple (Ananas comosus Merr.) Leaf Pulp and Paper Studied by Face-Centered Composite Experimental Design Tue, 19 Apr 2016 12:28:59 +0000 http://www.hindawi.com/journals/amse/2016/8915362/ Face-centered composite design (FCC) was used to study the effect of pulping variables: soda concentration (4-5 wt%), temperature (90–130°C), and pulping time (20–60 min) on the properties of pineapple leaf pulp and paper employing soda pulping. Studied pulp responses were screened yield and lignin content (kappa number). Paper properties, which include tensile index, burst index, and tear index, were also investigated. Effects of the pulping variables on the properties were statistically analyzed using Minitab 16. The optimum conditions to obtain the maximum tensile index were soda concentration of 4 wt%, pulping temperature of 105°C, and pulping time of 20 min. The predicted optimum conditions provided tensile index, burst index, tear index, screened yield, and kappa number of 44.13 kNm/kg, 1.76 kPam2, 1.68 Nm2/kg, 21.29 wt%, and 28.12, respectively, and were experimentally confirmed. Jantharat Wutisatwongkul, Nandh Thavarungkul, Jirawan Tiansuwan, and Preecha Termsuksawad Copyright © 2016 Jantharat Wutisatwongkul et al. All rights reserved. Microstructure and Mechanical Behavior of Hot Pressed Cu-Sn Powder Alloys Tue, 19 Apr 2016 08:42:12 +0000 http://www.hindawi.com/journals/amse/2016/9796169/ Cu-Sn based alloy powders with additives of elemental Pb or C were densified by hot pressing technique. The influence of densifying on the properties of the hot pressed materials was investigated. The properties, such as the hardness, compressive strength, and wear resistance of these materials, were determined. The hot pressed Cu-Sn specimens included intermetallic/phases, which were homogeneously distributed. The presence of graphite improved the wear resistance of Cu-Sn alloys three times. Similarly, the presence of lead improved the densification parameter of Cu-Sn alloys three times. There was no significant difference in the mechanical behavior associated with the addition of Pb to the Cu-Sn alloys, although Cu-Pb alloys showed considerably higher ultimate strength and higher elongation. The Cu-Sn-C alloys had lower strength compared with those of Cu-Sn alloys. Evidence of severe melting spots was noticed in the higher magnifications of the compression fracture surface of 85% Cu-10% Sn-5% C and 80% Cu-10% Sn-10% Pb alloys. This was explained by the release of load at the final event of the fracture limited area. Ahmed Nassef and Medhat El-Hadek Copyright © 2016 Ahmed Nassef and Medhat El-Hadek. All rights reserved. Nanostructural Deformation Analysis of Calcium Silicate Hydrate in Portland Cement Paste by Atomic Pair Distribution Function Mon, 18 Apr 2016 13:31:46 +0000 http://www.hindawi.com/journals/amse/2016/8936084/ The deformation of nanostructure of calcium silicate hydrate (C-S-H) in Portland cement (PC) paste under compression was characterized by the atomic pair distribution function (PDF), measured using synchrotron X-ray diffraction. The PDF of the PC paste exhibited a unique deformation behavior for a short-range order below 2.0 nm, close to the size of the C-S-H globule, while the deformation for a long-range order was similar to that of a calcium hydroxide phase measured by Bragg peak shift. The compressive deformation of the C-S-H nanostructure was comprised of three stages with different interactions between globules. This behavior would originate from the granular nature of C-S-H, which deforms with increasing packing density by slipping the interfaces between globules, rearranging the overall C-S-H nanostructure. This new approach will lead to increasing applications of the PDF technique to understand the deformation mechanism of C-S-H in PC-based materials. Hiroshi Suzuki, Sungchul Bae, and Manabu Kanematsu Copyright © 2016 Hiroshi Suzuki et al. All rights reserved. Ultra-High and Near-Zero Refractive Indices of Magnetron Sputtered Thin-Film Metamaterials Based on TixOy Mon, 18 Apr 2016 09:44:37 +0000 http://www.hindawi.com/journals/amse/2016/4565493/ Metamaterials based on with ultra-high and near-zero refractive indices were obtained by DC magnetron sputtering. The data on refractive indices, extinction coefficients, film thickness, and band gaps, obtained by spectroscopic ellipsometry, showed very high potential of these materials as metamaterials. Phase analysis performed by XRD revealed the presence of titanium phases with lower titanium oxidation states resulting from high concentration of oxygen vacancies, which are crucial for such extraordinary jumps and drops of refractive indices. Numerous band gaps for direct and indirect electron transitions additionally confirmed unique properties of these materials. Vukoman Jokanović, Božana Čolović, Miloš Nenadović, Anka Trajkovska Petkoska, Miodrag Mitrić, Bojan Jokanović, and Ilija Nasov Copyright © 2016 Vukoman Jokanović et al. All rights reserved. Pore Size Distribution Influence on Suction Properties of Calcareous Stones in Cultural Heritage: Experimental Data and Model Predictions Sun, 17 Apr 2016 11:11:25 +0000 http://www.hindawi.com/journals/amse/2016/7853156/ Water sorptivity symbolises an important property associated with the preservation of porous construction materials. The water movement into the microstructure is responsible for deterioration of different types of materials and consequently for the indoor comfort worsening. In this context, experimental sorptivity tests are incompatible, because they require large quantities of materials in order to statistically validate the results. Owing to these reasons, the development of analytical procedure for indirect sorptivity valuation from MIP data would be highly beneficial. In this work, an Intermingled Fractal Units’ model has been proposed to evaluate sorptivity coefficient of calcareous stones, mostly used in historical buildings of Cagliari, Sardinia. The results are compared with experimental data as well as with other two models found in the literature. IFU model better fits experimental data than the other two models, and it represents an important tool for estimating service life of porous building materials. Giorgio Pia, Ludovica Casnedi, and Ulrico Sanna Copyright © 2016 Giorgio Pia et al. All rights reserved. Multiobjective Optimization of Turning Cutting Parameters for J-Steel Material Thu, 14 Apr 2016 13:15:57 +0000 http://www.hindawi.com/journals/amse/2016/6429160/ This paper presents a multiobjective optimization study of cutting parameters in turning operation for a heat-treated alloy steel material (J-Steel) with Vickers hardness in the range of HV 365–395 using uncoated, unlubricated Tungsten-Carbide tools. The primary aim is to identify proper settings of the cutting parameters (cutting speed, feed rate, and depth of cut) that lead to reasonable compromises between good surface quality and high material removal rate. Thorough exploration of the range of cutting parameters was conducted via a five-level full-factorial experimental matrix of samples and the Pareto trade-off frontier is identified. The trade-off among the objectives was observed to have a “knee” shape, in which certain settings for the cutting parameters can achieve both good surface quality and high material removal rate within certain limits. However, improving one of the objectives beyond these limits can only happen at the expense of a large compromise in the other objective. An alternative approach for identifying the trade-off frontier was also tested via multiobjective implementation of the Efficient Global Optimization (m-EGO) algorithm. The m-EGO algorithm was successful in identifying two points within the good range of the trade-off frontier with 36% fewer experimental samples. Adel T. Abbas, Karim Hamza, Mohamed F. Aly, and Essam A. Al-Bahkali Copyright © 2016 Adel T. Abbas et al. All rights reserved. The Effect of Salt Solutions and Absorption Cycles in the Capillary and Drying Coefficient of Red Brick Samples with Different Joints Wed, 13 Apr 2016 14:29:04 +0000 http://www.hindawi.com/journals/amse/2016/7868194/ Rising damp can reduce building’s aesthetical value, comfort, and health mark when combined with the existence of soluble salts in the building components and in the ground water can even lead to material decomposition and compromise its structural performance. This research work intended to study the effect of different absorption cycles of two saturated solutions of sodium sulphate and potassium chloride in the capillary absorption curves obtained through the partial immersion of red brick samples without and with different joints. The results revealed significant differences in the capillary coefficients obtained when samples were tested with salt solutions. In the end of this paper an evaluation of the drying kinetics was presented for all the tested samples. Four different first-order kinetics models, available in the literature, were adjusted to describe the drying process and the results point that the Page and Logarithmic models allow the best fit. The apparent molecular diffusion coefficient for solid red brick samples saturated with different solutions and joints was also estimated. A. S. Guimarães, J. M. P. Q. Delgado, V. P. de Freitas, and A. P. Albuquerque Copyright © 2016 A. S. Guimarães et al. All rights reserved. Liquefaction Incidents of Mineral Cargoes on Board Bulk Carriers Wed, 13 Apr 2016 13:56:30 +0000 http://www.hindawi.com/journals/amse/2016/5219474/ Liquefaction is a frequently occurring problem taking place when transporting wet granular solid bulk cargoes on board bulk carriers. Liquefaction of a solid bulk cargo can occur when excessive dynamic loading, induced by rough seas and vessel vibrations, is transmitted to the cargo. From 1988 to 2015, there have been 24 suspected liquefaction incidents reported, which resulted in 164 casualties and the loss of 18 vessels. The objective of this study is to investigate the collective causes of liquefaction of solid bulk cargoes on board bulk carriers in order to make recommendations to prevent future incidents from occurring. This was achieved by analysing the seven available investigative reports relating to the incidents, focusing on the key findings and exploring the effect of excess moisture within the cargo. This study has placed significant emphasis on the importance of preventing ingress of water into the cargo during transportation, loading, and storage. Recommendations have been given, based on the key findings from the reports, to reduce the potential for liquefaction incidents to occur. Michael C. Munro and Abbas Mohajerani Copyright © 2016 Michael C. Munro and Abbas Mohajerani. All rights reserved. Microstructure and Electromagnetic Properties of Ni-Zn-Co Ferrite up to 20 GHz Wed, 13 Apr 2016 13:43:37 +0000 http://www.hindawi.com/journals/amse/2016/1934783/ The present paper examines the relation between different developed microstructures and the microwave electromagnetic properties in Ni-Zn-Co ferrite. To this end, the Ni0.25Zn0.25Co0.5Fe2O4 composition has been prepared with the conventional ceramic process with varied prefiring (750°C, 1000°C) and sintering top temperatures (1200°C, 1250°C). When lower temperatures are applied in these production stages, incomplete microstructures with low density, higher porosity, or finer grains are achieved. On account of these features, the contributions of domain wall motion and spin rotation to the complex permeability move to higher frequencies, whereas microwave dielectric permittivity is decreased. In particular in conjunction with the high Co content, the wall relaxation and spin resonance are interestingly forced to occur at 850 MHz and 8.05 GHz, respectively. Regarding the electromagnetic wave attenuation, the ferrite annealed at lower temperatures exhibits strong return loss peaks at higher frequencies, but without other performance improvement. We should notice that the variations in sintering temperature yield the maximum changes in the recorded parameters, including the coercive field, and , indicating the inferior role of prefiring in Ni-Zn ferrite. Charalampos Stergiou Copyright © 2016 Charalampos Stergiou. All rights reserved. A Microstructure Based Strength Model for Slag Blended Concrete with Various Curing Temperatures Tue, 12 Apr 2016 14:21:09 +0000 http://www.hindawi.com/journals/amse/2016/1738417/ Ground granulated blast furnace slag, which is a byproduct obtained during steel manufacture, has been widely used for concrete structures in order to reduce carbon dioxide emissions and improve durability. This paper presents a numerical model to evaluate compressive strength development of slag blended concrete at isothermal curing temperatures and time varying curing temperatures. First, the numerical model starts with a cement-slag blended hydration model which simulates both cement hydration and slag reaction. The accelerations of cement hydration and slag reaction at elevated temperatures are modeled by Arrhenius law. Second, the gel-space ratios of hardening concrete are calculated using reaction degrees of cement and slag. Using a modified Powers’ gel-space ratio strength theory, the strength of slag blended concrete is evaluated considering both strengthening factors and weakening factors involved in strength development process. The proposed model is verified using experimental results of strength development of slag blended concrete with different slag contents and different curing temperatures. Li-Na Zhang, Wang Xiao-Yong, and Kyung-Taek Koh Copyright © 2016 Li-Na Zhang et al. All rights reserved. Damage Identification and Performance Assessment of Regular and Irregular Buildings Using Wavelet Transform Energy Thu, 07 Apr 2016 11:48:17 +0000 http://www.hindawi.com/journals/amse/2016/6027812/ This study investigates a novelty wavelet application for damage detection of regular and irregular building structures under seismic load effects. The energy of wavelet transform and correlation coefficient are used to detect the performance of the damaged building. The simple 3D regular and irregular simulation (finite element model) models of a building are designed to verify the methods’ uses and optimum applications. The obtained results reveal that the energy of Discrete Wavelet Transform (DWT) shows significantly higher performance than the energy of Continuous Wavelet Transform (CWT) in detecting the damage of the building, and the performance of irregular buildings appeared suitable for use in the seismically active areas. In addition, it can be concluded that the correlation coefficient can be applied to study the effects of damage and the safety of structures. Mosbeh R. Kaloop and Jong Wan Hu Copyright © 2016 Mosbeh R. Kaloop and Jong Wan Hu. All rights reserved. Effects of Nanosilica on Compressive Strength and Durability Properties of Concrete with Different Water to Binder Ratios Wed, 06 Apr 2016 08:04:40 +0000 http://www.hindawi.com/journals/amse/2016/8453567/ The effects of the addition of different nanosilica dosages (0.5%, 1%, and 1.5% with respect to cement) on compressive strength and durability properties of concrete with water/binder ratios 0.65, 0.55, and 0.5 were investigated. Water sorptivity, apparent chloride diffusion coefficient, electrical resistivity, and carbonation coefficient of concrete were measured. The results showed that compressive strength significantly improved in case of water/binder = 0.65, while for water/binder = 0.5 no change was found. Increasing nanosilica content, the water sorptivity decreased only for water/binder = 0.55. The addition of 0.5% nanosilica decreased the apparent chloride diffusion coefficient for water/binder = 0.65 and 0.55; however, higher nanosilica dosages did not decrease it with respect to reference value. The resistivity was elevated by 0.5% nanosilica for all water/binder ratios and by 1.5% nanosilica only for water/binder = 0.5. The carbonation coefficient was not notably affected by increasing nanosilica dosages and even adverse effect was observed for water/binder = 0.65. Further information of microstructure was also provided through characterization techniques such as X-ray diffraction, thermal gravimetric analysis, mercury intrusion porosimetry, and scanning electron microscopy. The effectiveness of a certain nanosilica dosage addition into lower strength mixes was more noticeable, while, for the higher strength mix, the effectiveness was less. Forood Torabian Isfahani, Elena Redaelli, Federica Lollini, Weiwen Li, and Luca Bertolini Copyright © 2016 Forood Torabian Isfahani et al. All rights reserved. Macro/Microtesting and Damage and Degradation of Sandstones under Dry-Wet Cycles Tue, 05 Apr 2016 13:27:04 +0000 http://www.hindawi.com/journals/amse/2016/7013032/ In terms of the degradation of mechanical parameters of rock mass in the hydrofluctuation belt of a reservoir bank slope arising from rainfall and the reservoir level fluctuation, the moderately weathered sandstone in a side slope of the Three Gorges Reservoir Region is selected as a research object to carry out “drying-saturation-drying” tests for disks with two thicknesses ( mm,  mm) in different cycles; a spiral CT machine, an ultrasonic velocity meter, and a light Schmidt hammer are utilzed to conduct nondestructive testing on dry-wet cycles; through the Brazilian splitting test, the uniaxial tensile strength of “dry” and “saturated” sandstones under different dry-wet cycles is obtained. The research shows that, with the increase of the dry-wet circles (), the longitudinal wave velocity and the rebound strength of sandstones are linearly decreased with ; the uniaxial tensile strength of sandstones and the mean CT number of cross sections are logarithmically decreased with ; the fitting equation of macro/micromechanical parameters and dry-wet cycles () of sandstones is raised, which is provided as a reference basis for the weathering process of sandstones under dry-wet cycles. Xinrong Liu, Zijuan Wang, Yan Fu, Wen Yuan, and Luli Miao Copyright © 2016 Xinrong Liu et al. All rights reserved. Study of Tribological Behavior of Silicon Carbide Based Aluminum Metal Matrix Composites under Dry and Lubricated Environment Tue, 05 Apr 2016 07:37:08 +0000 http://www.hindawi.com/journals/amse/2016/3813412/ Friction and wear behavior of silicon carbide based aluminum metal matrix composite and aluminum matrix alloy have been studied for sliding speeds of 3.14 m/s and 3.77 m/s and load range from 10 N to 30 N under dry and lubricated environment, respectively. The experiments were performed on pin on disk tribometer (Make: DUCOM). The composite was fabricated by stir casting process and has several challenges like inferior bonds and interfacial reaction products which will deteriorate the mechanical and tribological properties. Therefore, addition of reactive metal like magnesium (Mg) should be done which will lead to reduced solidification shrinkage, lower tendency towards hot tearing, and faster process cycles. Results have revealed that the developed composites have lower coefficient of friction and wear rates when compared with aluminum matrix alloy under dry and lubricated environment. Experimental results show that under dry condition coefficient of friction of both the matrix alloy and the composite decreases with increase in load, whereas it increases with increase in sliding speeds; on the other hand wear rates of both aluminum matrix alloy and the composites increase with increase in load as well as with sliding speeds. FESEM of worn surfaces are also used to understand the wear mechanisms. Kalyan Kumar Singh, Saurabh Singh, and Anil Kumar Shrivastava Copyright © 2016 Kalyan Kumar Singh et al. All rights reserved. Optimizing Cutting Conditions for Minimum Surface Roughness in Face Milling of High Strength Steel Using Carbide Inserts Mon, 04 Apr 2016 13:57:13 +0000 http://www.hindawi.com/journals/amse/2016/7372132/ A full factorial design technique is used to investigate the effect of machining parameters, namely, spindle speed , depth of cut and table feed rate on the obtained surface roughness ( and ) during face milling operation of high strength steel. A second-order regression model was built using least squares method depending on the factorial design results to approximate a mathematical relationship between the surface roughness and the studied process parameters. Analysis of variance was conducted to estimate the significance of each factor and interaction with respect to the surface roughness. For , the results show that spindle speed, depth of cut, and table feed rate have a significant effect on the surface roughness in both linear and quadratic terms. There is also an interaction between depth of cut and feed rate. It also appears that feed rate has the greatest effect on the data variation followed by depth of cut. For , the results show that the table feed rate is the most effective factor followed by the depth of cut, while the spindle speed had a significant small effect only in its quadratic term. The conditions of minimum and are identified through least square optimization. Moreover, multiobjective optimization for minimizing and maximizing metal removal rate is conducted and the results are presented. Adel Taha Abbas, Adham Ezzat Ragab, Essam Ali Al Bahkali, and Ehab Adel El Danaf Copyright © 2016 Adel Taha Abbas et al. All rights reserved. Maillard Reaction in Natural Rubber Latex: Characterization and Physical Properties of Solid Natural Rubber Sun, 03 Apr 2016 08:25:34 +0000 http://www.hindawi.com/journals/amse/2016/7807524/ Maillard reaction in Natural Rubber (NR) latex was investigated by treating fresh NR latex with glutaraldehyde (C5H8O2) in amounts of 0, 50, 100, and 200 mmol/kg of latex. Protein cross-linking in fresh NR latex and solid NR was confirmed by using sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE) and attenuated total reflection infrared (ATR-IR) spectroscopy, respectively. It was found that degree of protein cross-linking in NR increased with increasing C5H8O2 concentration. Physical properties of untreated and treated NR substances in terms of gel content, initial Wallace plasticity (), plasticity retention index (PRI), Mooney viscosity, and tensile strength were carefully explored. Results clearly showed that the Maillard cross-linking of proteins had remarkable effect on bulk NR properties, that is, solvent resistance, hardness, resistance to oxidation, rheological behavior, and resistance to stretching out. S. Montha, P. Suwandittakul, A. Poonsrisawat, P. Oungeun, and C. Kongkaew Copyright © 2016 S. Montha et al. All rights reserved. Evaluating the Effects of Chemical Composition on Induction Heating Ability of Fe2O3-CaO-SiO2 Glass Ceramics Sun, 03 Apr 2016 06:47:12 +0000 http://www.hindawi.com/journals/amse/2016/2539468/ In order to investigate the relationship between induction heating ability of Fe2O3-CaO-SiO2 glass ceramics and chemical composition, a series of glass ceramic samples with different chemical compositions were prepared by the sol-gel method. The structural, textural, and magnetic properties of the samples were analyzed and correlated with the Fe2O3 content. This is the first time work of its kind that evaluates the relationships between induction heating ability and chemical composition of Fe2O3-CaO-SiO2 glass ceramics. The results showed that induction heating ability of Fe2O3-CaO-SiO2 glass ceramics increased gradually with increasing magnetite content. Also, the induction heating ability became considerably better when a small amount of phosphorus was introduced. This study thus reveals a methodology to control the induction heating ability of Fe2O3-CaO-SiO2 glass ceramics through modifying the chemical composition. Y. Y. Wang, B. Li, Y. L. Yu, and P. S. Tang Copyright © 2016 Y. Y. Wang et al. All rights reserved. Dynamic Behaviors of Contact Lines on Micropillared Hydrophobic Surfaces Thu, 31 Mar 2016 17:29:21 +0000 http://www.hindawi.com/journals/amse/2016/3278789/ The dynamic characteristics of contact lines on inclined micropillared surfaces were investigated in this paper. It was observed that the contact lines varied gradually to a ladder shape with the droplet sliding on micropillared surfaces under Wenzel state. The dynamic deformation of contact lines would be more obvious under Wenzel state and Cassie impregnating state; however it is negligible when the droplet is in one-dimensional scenario. Droplet layers formed during droplet sliding were left behind and evaporated quickly and disappeared. Based on these characteristics, the comparison of experimental data with theoretical models was discussed. It was found that energy barrier played an important role in analyzing wetting characteristics. Because of ignoring the role of energy barrier, the model of sliding angle cannot predict the sliding angle on micropillared surfaces very well, especially when the area fraction is small. This work is helpful to propose a more accuracy sliding angle model. Chen-chuan Tan, Zhi-hai Jia, Hui-nan Yang, and Tai-min Cai Copyright © 2016 Chen-chuan Tan et al. All rights reserved. Short-Term Creep Experiment of Cement Asphalt Mortar and Its Numerical Simulation Thu, 31 Mar 2016 07:44:21 +0000 http://www.hindawi.com/journals/amse/2016/7684641/ In order to investigate the creep performance of cement asphalt mortar (CA mortar), the field sampling of CA mortar cylinder samples was produced, and all samples were tested on WDW series electric universal testing machine by using uniaxial static creep test at 25°C, and the load stress levels were 0.05 MPa, 0.1 MPa, 0.3 MPa, and 0.5 MPa. The greater the load is, the bigger the creep deformation is. The creep performance was simulated by using Burgers model, and the correlation coefficients between fitting results of Burgers model and experimental results are all greater than 0.9. Based on the requirements of finite element software, the Prony series of Burgers model was obtained, and the short-term creep process of CA mortar was simulated by the finite element software ANSYS. The relative error between simulation results and experimental data is not more than 2.5%, which indicates that the short-creep process of CA mortar can be simulated by ANSYS software. The study results can improve the structural design theory of slab track. Hao Xu, Ping Wang, Hong-song Lin, and Hua Yan Copyright © 2016 Hao Xu et al. All rights reserved. Soil Erosion Estimation Using Remote Sensing Techniques in Wadi Yalamlam Basin, Saudi Arabia Wed, 30 Mar 2016 13:25:54 +0000 http://www.hindawi.com/journals/amse/2016/9585962/ Soil erosion is one of the major environmental problems in terms of soil degradation in Saudi Arabia. Soil erosion leads to significant on- and off-site impacts such as significant decrease in the productive capacity of the land and sedimentation. The key aspects influencing the quantity of soil erosion mainly rely on the vegetation cover, topography, soil type, and climate. This research studies the quantification of soil erosion under different levels of data availability in Wadi Yalamlam. Remote Sensing (RS) and Geographic Information Systems (GIS) techniques have been implemented for the assessment of the data, applying the Revised Universal Soil Loss Equation (RUSLE) for the calculation of the risk of erosion. Thirty-four soil samples were randomly selected for the calculation of the erodibility factor, based on calculating the -factor values derived from soil property surfaces after interpolating soil sampling points. Soil erosion risk map was reclassified into five erosion risk classes and 19.3% of the Wadi Yalamlam is under very severe risk (37,740 ha). GIS and RS proved to be powerful instruments for mapping soil erosion risk, providing sufficient tools for the analytical part of this research. The mapping results certified the role of RUSLE as a decision support tool. Jarbou A. Bahrawi, Mohamed Elhag, Amal Y. Aldhebiani, Hanaa K. Galal, Ahmad K. Hegazy, and Ebtisam Alghailani Copyright © 2016 Jarbou A. Bahrawi et al. All rights reserved.