Advances in Materials Science and Engineering The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Nonlinear Finite Element Analysis of the Fluted Corrugated Sheet in the Corrugated Cardboard Wed, 23 Jul 2014 11:51:24 +0000 The choice of corrugated medium, flute size, combining adhesive, and linerboards can be varied to design a corrugated board with specific properties. In this paper, the nonlinear finite element analysis of the fluted corrugated sheet in the corrugated cardboard based on software SolidWorks2008 was investigated. The model of corrugated board with three or more flutes is reliable for stress and displacement measurement to eliminate the influence of the number of flutes in models. According to the static pressure test, with the increase of flute height or arc radius of flute, the maximum stress in the models decreased and the maximum displacement increased. However the maximum stress and maximum displacement in the models increase nonlinearly in the static pressure test with the increase of the flute angle . According to the drop test, with the increase of flute height , the maximum stress of goods on the upper board in the drop test decreased. The maximum stress of the model in the drop test decreases firstly and then increases with the increase of flute angle, and the optimal flute angle could be 60° for corrugated board. All the conclusions are consistent with experimental data or product standards. Zhiguo Zhang, Tao Qiu, Riheng Song, and Yaoyu Sun Copyright © 2014 Zhiguo Zhang et al. All rights reserved. The Research of Degradation about 1,2,4-Trichlorobenzene by the Artificial Media in Microbe Enrichment Mon, 21 Jul 2014 12:02:54 +0000 Artificial media were used to enrich microbe and improve the water resource quality; therefore trace quantity organic pollutants of 1,2,4-trichlorobenzene were biodegraded. The result of the test showed that, after domestication, the microassociation enriched in the assembled medium could remove corresponding trace quantity organic pollutants in some concentration. When the temperature was 30 degree centigrade, and the pH was between 6 and 9, the effect about the removal on trace-quantity-organic pollutants water was the best. A strain of bacteria that could degrade 1,2,4-trichlorobenzene was separated, and its degradation mechanism to 1,2,4-trichlorobenzene was studied. At the same time, the congener trace quantity organic pollutants could be biodegraded. Biofilm after domestication can effectively degrade a certain concentration range of three trichlorobenzenes and the removal effect of HRT = 7 d was better than the removal effect of HRT = 5 d. It is evident that the trace quantity organic pollutants of 1,2,4-trichlorobenzene in the source water quality from Meiliang Bay in Taihu Lake can be well degraded by enriched microbes on the artificial media. Dong-ying Xu Copyright © 2014 Dong-ying Xu. All rights reserved. Synthesis and Characterization of Acrylamide-Based Anionic Copolymer and Investigation of Solution Properties Mon, 21 Jul 2014 11:04:13 +0000 The copolymer of acrylamide (AM) and 2-acrylamido-2-methyl-1-propane sulfonic acid (AMPS) was synthesized through radical solution polymerization by potassium persulfate as initiator. By changing the AMPS feed ratio from 10 to 70%, and keeping other reaction conditions constant, different copolymers were synthesized. The techniques of Fourier transform infrared (FTIR) and nuclear magnetic resonance (1H- 13C-NMR) spectroscopy were used for identification of functional groups and confirmation of copolymers’ structure. Intrinsic and apparent viscosity of samples were measured in aqueous sodium chloride solution under standard conditions. The anionic degree of copolymers was determined by back titration method and by 13C-NMR spectroscopy. Molecular weight of copolymers was determined by the Mark-Houwink relationship. The measured molecular weight of samples showed that we have acquired a high molecular weight product. The effect of different range of shear rates on solution viscosity was evaluated. The copolymer solutions showed non-Newtonian shear thinning behavior. The performance of copolymers with respect to shear resistance and molecular weight was evaluated from industry application standpoint. H. Jamshidi and A. Rabiee Copyright © 2014 H. Jamshidi and A. Rabiee. All rights reserved. Comprehensive Analysis of Fault Diagnosis Methods for Aluminum Electrolytic Control System Mon, 21 Jul 2014 08:22:24 +0000 This paper established the fault diagnosis system of aluminum electrolysis, according to the characteristics of the faults in aluminum electrolysis. This system includes two subsystems; one is process fault subsystem and the other is fault subsystem. Process fault subsystem includes the subneural network layer and decision fusion layer. Decision fusion neural network verifies the diagnosis result of the subneural network by the information transferring over the network and gives the decision of fault synthetically. EMD algorithm is used for data preprocessing of current signal in stator of the fault subsystem. Wavelet decomposition is used to extract feature on current signal in the stator; then, the system inputs the feature to the rough neural network for fault diagnosis and fault classification. The rough neural network gives the results of fault diagnosis. The simulation results verify the feasibility of the method. Jie-jia Li, Xiao-yan Han, Peng Zhou, Xiao-yu Sun, and Na Chang Copyright © 2014 Jie-jia Li et al. All rights reserved. Smooth Particle Hydrodynamics Simulation of Micro-Cup-Extrusion Using a Graphit-ic Coating Mon, 21 Jul 2014 08:05:13 +0000 Microextrusion is becoming increasingly important for the manufacturing of microcomponents. However, this reduction in scale to a microlevel means that the influence of friction and the need for suitable lubrication are greatly increased. This study therefore looks at the use of a low-friction and highly wear resistant Graphit-ic coating on the mold-forming section of a microextrusion mold, this coating being applied by a closed-field unbalanced magnetron sputter ion plating technique. A microcup of CuZn33 brass alloy was then extruded, with a wall thickness of 0.45 mm, outside diameter of 2.9 mm, and an internal diameter of 2 mm. The experimental results in which extrusion uses the mold coating with Graphit-ic film are compared against the experimental results in which extrusion uses the mold uncoating with Graphit-ic film. This showed that the load was decreased a lot and the self-lubricating solid coating facilitates a smooth extrusion process. As the extrusion rate was quite high, smoothed particle hydrodynamics method simulations of the extrusion process were conducted, these being then compared with the experimental results. These result showed that the SPH simulation can be applied to show the deformation of materials and predict the load trend. Li Shi-Cheng, Chen Ze-Zhong, Zheng Jie, and Wang Dong-Feng Copyright © 2014 Li Shi-Cheng et al. All rights reserved. Fabrication of Upconverting Hybrid Nanoparticles for Near-Infrared Light Triggered Drug Release Mon, 21 Jul 2014 00:00:00 +0000 Low tissue penetration and harmful effects of (ultraviolet) UV or visible light on normal tissue limit exploiting nanocarriers for the application of light-controlled drug release. Two strategies may solve the problem: one is to improve the sensitivity of the nanocarriers to light to decrease the radiation time; the other one is using more friendly light as the trigger. In this work, we fabricated a core-shell hybrid nanoparticle with an upconverting nanoparticle (UCNP) as the core and thermo- and light-responsive block copolymers as the shell to combine the two strategies together. The results indicated that the sensitivity of the block copolymer to light could be enhanced by decreasing the photolabile moieties in the polymer, and the UCNP could transfer near-infrared (NIR) light, which is more friendly to tissue and cell, to UV light to trigger the phase conversion of the block polymers in situ. Using Nile Red (NR) as the model drug, the hybrid nanoparticles were further proved to be able to act as carriers with the character of NIR triggered drug release. Ranran Zhang, Risheng Yao, Binbin Ding, Yuxin Shen, Shengwen Shui, Lei Wang, Yu Li, Xianzhu Yang, and Wei Tao Copyright © 2014 Ranran Zhang et al. All rights reserved. The Effect of Variation of Molarity of Alkali Activator and Fine Aggregate Content on the Compressive Strength of the Fly Ash: Palm Oil Fuel Ash Based Geopolymer Mortar Sun, 20 Jul 2014 06:43:36 +0000 The effect of molarity of alkali activator, manufactured sand (M-sand), and quarry dust (QD) on the compressive strength of palm oil fuel ash (POFA) and fly ash (FA) based geopolymer mortar was investigated and reported. The variable investigated includes the quantities of replacement levels of M-sand, QD, and conventional mining sand (N-sand) in two concentrated alkaline solutions; the contents of alkaline solution, water, POFA/FA ratio, and curing condition remained constant. The results show that an average of 76% of the 28-day compressive strength was found at the age of 3 days. The rate of strength development from 3 to 7 days was found between 12 and 16% and it was found much less beyond this period. The addition of 100% M-sand and QD shows insignificant strength reduction compared to mixtures with 100% N-sand. The particle angularity and texture of fine aggregates played a significant role in the strength development due to the filling and packing ability. The rough texture and surface of QD enables stronger bond between the paste and the fine aggregate. The concentration of alkaline solution increased the reaction rate and thus enhanced the development of early age strength. The use of M-sand and QD in the development of geopolymer concrete is recommended as the strength variation between these waste materials and conventional sand is not high. Iftekhair Ibnul Bashar, U. Johnson Alengaram, Mohd Zamin Jumaat, and Azizul Islam Copyright © 2014 Iftekhair Ibnul Bashar et al. All rights reserved. Characterization and Alumina Leachability of 12CaO·7Al2O3 with Different Holding Times Sun, 20 Jul 2014 00:00:00 +0000 The effect of synthesis time on phase compositions, lattice constant, average grain size, preferred orientation, and surface morphology of 12CaO·7Al2O3 synthesized at 1500°C was analyzed by XRD and SEM. The results indicate that the main phase of samples synthesized is 12CaO·7Al2O3 when holding time is over 30 min. The lattice constant increases and the preferred orientation decreases as synthesis time prolongs. The average grain size of samples is about 59 nm calculated by Scherrer formula, and it does not change with synthesis time. The synthesis time affects the micromorphology of samples greatly. There are more and bigger holes in samples synthesized for long time. The aspects mentioned above cause the alumina leaching ratio of 12CaO·7Al2O3 to increase with the prolonging of synthesis time, but the rate of increase drops. Hui-lan Sun, Bo Wang, Jian-xin Zhang, and Shu-feng Zong Copyright © 2014 Hui-lan Sun et al. All rights reserved. Investigation of Mechanical Properties and Plastic Deformation Behavior of (Ti45Cu40Zr10Ni5)100−xAlx Metallic Glasses by Nanoindentation Thu, 17 Jul 2014 12:24:19 +0000 The effect of Al addition on mechanical properties and plastic deformation behavior of (Ti45Cu40Zr10Ni5)100−xAlx (x = 0, 2, 4, 6 and 8) amorphous alloy ribbons have been investigated by nanoindentation. The hardness and elastic modulus do not simply increase with the increase of Al content. The alloy with 8 at.% Al exhibits the highest hardness and elastic modulus. The serrations or pop-in events are strongly dependent on the loading rate and alloy composition. Lanping Huang, Xuzhe Hu, TaoTao Guo, and Song Li Copyright © 2014 Lanping Huang et al. All rights reserved. Estimating Young’s Modulus of Materials by a New Three-Point Bending Method Thu, 17 Jul 2014 06:28:45 +0000 A new test method based on the three-point bending test is put forward to measure Young’s modulus of materials. The simplified mechanical model is established to make theoretical derivation. This method has not only the advantages of simple specimen preparation and convenient loading device, but also higher precision than the traditional three-point bending method. The method is adopted to obtain Young’s modulus of the aluminum alloy 2024. The feasibility of the method has been demonstrated by comparisons with the corresponding results obtained from the finite element method and experiment method. And the influence of contact friction on the test accuracy is analyzed. Xiaohu Zeng, Shifeng Wen, Mingxi Li, and Gongnan Xie Copyright © 2014 Xiaohu Zeng et al. All rights reserved. Experimental Study on Early-Age Crack of Mass Concrete under the Controlled Temperature History Tue, 15 Jul 2014 10:23:58 +0000 Thermal deformation under restrained conditions often leads to early-age cracking and durability problems in mass concrete structures. It is crucial to monitor accurately the evolution of temperature and thermal stresses. In this paper, experimental studies using temperature stress testing machine (TSTM) are carried out to monitor the generated thermal cracking in mass concrete. Firstly, components and working principle of TSTM were introduced. Cracking temperatures and stress reserves are selected as the main cracking evaluation indicators of TSTM. Furthermore, effects of temperature controlling measures on concrete cracking were quantitatively studied, which consider the concrete placing temperature (before cooling) and cooling rates (after cooling). Moreover, the influence of reinforcement on early-age cracking has been quantitatively analyzed using the TSTM. The experimental results indicate that the crack probability of reinforced concrete (RC) is overestimated. Theoretical calculations proved that the internal stress can transfer from concrete to reinforcement due to creep effect. Finally, the experimental results indicate that the reinforcement can improve the crack resistance of concrete by nearly 30% in the TSTM tests, and the ultimate tensile strain of RC is approximately 105% higher than that of plain concrete with the same mix proportions. Nannan Shi, Jianshu Ouyang, Runxiao Zhang, and Dahai Huang Copyright © 2014 Nannan Shi et al. All rights reserved. Preparation of Aligned ZnO Nanorod Arrays on Sn-Doped ZnO Thin Films by Sonicated Sol-Gel Immersion Fabricated for Dye-Sensitized Solar Cell Mon, 14 Jul 2014 07:11:57 +0000 Aligned ZnO Nanorod arrays are deposited on the Sn-doped ZnO thin film via sonicated sol-gel immersion method. The structural, optical, and electrical properties of the Sn-doped ZnO thin films were investigated. Results show that the Sn-doped ZnO thin films with small grain size (~20 nm), high average transmittance (96%) in visible region, and good resistivity ·cm are obtained for 2 at.% Sn doping concentration. The aligned ZnO nanorod arrays with large surface area were also obtained for 2 at.% Sn-doped ZnO thin film. They were grown on sol-gel derived Sn-doped ZnO thin film, which acts as a seed layer, via sonicated sol-gel immersion method. The grown aligned ZnO nanorod arrays show high transmittance at visible region. The fabricated dye-sensitised solar cell based on the 2.0 at.% Sn-doped ZnO thin film with aligned ZnO nanorod arrays exhibits improved current density, open-circuit voltage, fill factor, and conversion efficiency compared with the undoped ZnO and 1 at.% Sn-doped ZnO thin films. I. Saurdi, M. H. Mamat, M. F. Malek, and M. Rusop Copyright © 2014 I. Saurdi et al. All rights reserved. Strengthening Reinforced Concrete Beams with CFRP and GFRP Sun, 13 Jul 2014 11:30:48 +0000 Concrete beams were strengthened by wrapping the shear edges of the beams twice at 45° in opposite directions by either carbon fiber reinforced polymer (CFRP) or glass fiber reinforced polymer (GFRP). The study included 3 CFRP wrapped beams, 3 GFRP wrapped beams, and 3 control beams, all of which were 150 250 2200 mm and manufactured with C20 concrete and S420a structural steel at the Gazi University Technical Education Faculty labs, Turkey. Samples in molds were cured by watering in the open air for 21 days. Four-point bending tests were made on the beam test specimens and the data were collected. Data were evaluated in terms of load displacement, bearing strength, ductility, and energy consumption. In the CFRP and GFRP reinforced beams, compared to controls, 38% and 42%, respectively, strength increase was observed. In all beams, failure-flexural stress occurred in the center as expected. Most cracking was observed in the flexural region 4. A comparison of CFRP and GFRP materials reveals that GFRP enforced parts absorb more energy. Both materials yielded successful results. Thicker epoxy application in both CFRP and GFRP beams was considered to be effective in preventing break-ups. Mehmet Mustafa Önal Copyright © 2014 Mehmet Mustafa Önal. All rights reserved. Promising Poly(-caprolactone) Composite Reinforced with Weft-Knitted Polyester for Small-Diameter Vascular Graft Application Thu, 10 Jul 2014 11:40:36 +0000 The present study was designed to improve the mechanical performance of a small-diameter vascular prosthesis made from a flexible membrane of poly(ε-caprolactone) (PCL). PCL reinforcement was achieved by embedding a tubular fabric knitted from polyethylene terephthalate (PET) yarns within the freeze-dried composite structure. The knitting density of PET fabric influenced the mechanical properties of the new vascular graft. Results showed that the composite prototype has good mechanical properties, water permeability, elastic recovery, and suture retention strength. Increases in loop density increased compressive strength and suture retention strength and decreased elastic recovery. The new composite prototype vascular graft has promising potential applications in clinics because of its excellent mechanical properties. Fu-Jun Wang, Abedalwafa Mohammed, Chao-Jing Li, and Lu Wang Copyright © 2014 Fu-Jun Wang et al. All rights reserved. Using Multilayered Substrate Integrated Waveguide to Design Microwave Gain Equalizer Thu, 10 Jul 2014 09:50:51 +0000 This paper presents the design and experiment of a novel microwave gain equalizer based on the substrate integrated waveguide (SIW) technique. The proposed equalizer is formed by an SIW loaded by SIW resonators, which has very compact structure and can compensate for gain slope of microwave systems. Equivalent circuit analysis is given about the proposed structure for a better insight into the structure’s response. A Ku-Band equalizer with four SIW resonators is simulated and fabricated with a multilayer printed circuit board process. The measured results show good performance and agreement with the simulated results; an attenuation slope of −4.5 dB over 12.5–13.5 GHz is reached with a size reduction of 76%. Yongfei Wang, Dongfang Zhou, Yi Zhang, and Chaowen Chang Copyright © 2014 Yongfei Wang et al. All rights reserved. Characterization of Material Stiffness on Injection Moulded Microspecimens Using Different Test Methods Thu, 10 Jul 2014 08:07:47 +0000 Injection moulding of polymer microparts can result in modified material behaviour due to process-induced changes in the internal properties. Thus, a transfer of the mechanical material properties in microparts, determined and valid on standardized test specimens, is only partially possible and should be verified on microtest specimens. This paper investigates both tensile and bending test methods for a suitable characterization of material stiffness in polymer microparts. For this purpose a down-scaled standard specimen is used and tested with different testing methods. The investigations reveal that the different testing methods result in comparable mechanical values. The effects of process-induced modified mechanical behaviour are observable in the investigated testing methods. Consequently, a microbending test is potentially a suitable method for characterizing material stiffness using microspecimens. Dietmar Drummer, Andreas Seefried, and Steve Meister Copyright © 2014 Dietmar Drummer et al. All rights reserved. Investigation on Dynamic Recrystallization Behavior of Martensitic Stainless Steel Wed, 09 Jul 2014 11:18:50 +0000 The hot deformation behavior of X20Cr13 martensitic stainless steel was studied using the hot compression flow curves corresponding to the temperature range of 900–1150°C under strain rates from 0.01 to 10 s−1. A new mathematical model to estimate the flow stress under hot deformation conditions up to the peak of the flow curves was developed. The critical strains for initiation of dynamic recrystallization were also derived by the developed model. Furthermore, the effects of Zener-Hollomon parameter on the characteristic points of the flow curves were studied using the power law relation. The deformation activation energy obtained for this steel was 359.4 kJ/mol in the temperature range from 900°C to 1150°C. At the same time, the Avrami kinetic equation of dynamic recrystallization for X20Cr13 steel and the recrystallized grain size model were also established. Good agreement was obtained between the predictions and the experimental values. Facai Ren, Fei Chen, and Jun Chen Copyright © 2014 Facai Ren et al. All rights reserved. New Developments in Geotechnical Earthquake Engineering Mon, 07 Jul 2014 10:04:52 +0000 Based on the review on the advances of several important problems in geotechnical seismic engineering, the authors propose the initial analysis theory of time-frequency-amplitude (known as TFA for short), in an effort to realize the organic combination of time and frequency information and develop a groundbreaking concept to the traditional idea in the geotechnical seismic engineering area. Yang Changwei, Su Tianbao, Zhang Jianjing, and Du Lin Copyright © 2014 Yang Changwei et al. All rights reserved. Advances in Friction Welding Thu, 03 Jul 2014 09:05:22 +0000 Wenya Li, Achilleas Vairis, and R. Mark Ward Copyright © 2014 Wenya Li et al. All rights reserved. Perspectives for Titanium-Derived Fillers Usage on Denture Base Composite Construction: A Review Article Wed, 02 Jul 2014 11:45:54 +0000 Poly(methyl methacrylate) (PMMA) is an extensively used material in dentistry because of its aesthetics, processability, and reparability. However, PMMA is still far from being ideal in fulfilling the mechanical requirements of prosthesis. PMMA-based denture base polymers exhibit low fracture resistance and radiopacity behavior. Efforts to improve the mechanical and radiopacity properties of denture base materials through inclusion of silica-based fillers are ongoing. Although silane-treated siliceous fillers are commonly used, they are not sufficiently strong. They also exhibit cracks, which either cut through the glass fillers or propagate around the filler particles. This defect occurs when the dental composites are placed in aqueous oral environment because of the hydrolytic degradation of silica-based fillers and silane-coupling agents. The clinical problem of using silanes in adhesion promotion is bond degradation over time in oral environment. In addition, silanes do not bond effectively to nonsilica-based dental restorative materials. This review presents titanium-derived fillers as alternatives to siliceous fillers. Titanate-coupling agents are found to be effective couplers in treating Ti-based fillers because of their chemical compatibility and relatively high stability in aqueous environment. Nidal W. Elshereksi, Mariyam J. Ghazali, Andanastuti Muchtar, and Che H. Azhari Copyright © 2014 Nidal W. Elshereksi et al. All rights reserved. Evaluation of the Response of Posttensioned Steel Frames with Energy Dissipators Using Equivalent Single-Degree-of-Freedom Systems Wed, 02 Jul 2014 07:15:59 +0000 The hysteretic energy () dissipated in posttensioned steel frames (PTSF) with hysteretic dampers is calculated by using equivalent single-degree-of-freedom systems (ESDOFS), where the nonlinearity of both the steel bars (beam and columns) and the connections of the structural frame is separately considered. Five multi-degree-of-freedom (MDOFS) PTSF and their corresponding ESDOFS are studied under the action of 30 seismic motions recorded in soft ground, scaled in terms of the spectral pseudoacceleration evaluated at the fundamental period of the structures. Several simple mathematical expressions are proposed. The first expression is useful to calculate modifying factors () to relate of the ESDOFS with that of the MDOFS; the second is to determine the interstory drift (γ) as a function of the seismic intensity. The third equation is to calculate the factor of the relative participation of the energy that the connections dissipate with respect to the total energy and the fourth equation, which is function of the γ, is to obtain the distribution factors of through the height of the structure. The methodology proposed can be used for the design or the structural revision of PTSF with dampers. J. Luz Rivera, Arturo López-Barraza, Sonia E. Ruiz, and Alfredo Reyes-Salazar Copyright © 2014 J. Luz Rivera et al. All rights reserved. The Mechanical Behavior of Fiber Reinforced PP ECC Beams under Reverse Cyclic Loading Wed, 02 Jul 2014 00:00:00 +0000 When a structure is hit by earthquake, tremendous amount of seismic energy is released and structure is subjected to reverse loads. The mechanical properties of FRP reinforced PP ECC beams and coupon RC beam under reverse cyclic load controlled by displacement are investigated. Curing ages, reinforcement ratio, and volume fraction of PP fiber are parameters under survey. It is shown that multiple saturated cracking occurred in PP ECC beam and no crushing appeared. The PP ECC can enhance strength and energy dissipation capacity which are important to evaluate the performance of structures subjected to reverse cyclic loading. Yaw ChiaHwan and Han JianBo Copyright © 2014 Yaw ChiaHwan and Han JianBo. All rights reserved. Preparation and Stability of Inorganic Solidified Foam for Preventing Coal Fires Wed, 02 Jul 2014 00:00:00 +0000 Inorganic solidified foam (ISF) is a novel material for preventing coal fires. This paper presents the preparation process and working principle of main installations. Besides, aqueous foam with expansion ratio of 28 and 30 min drainage rate of 13% was prepared. Stability of foam fluid was studied in terms of stability coefficient, by varying water-slurry ratio, fly ash replacement ratio of cement, and aqueous foam volume alternatively. Light microscope was utilized to analyze the dynamic change of bubble wall of foam fluid and stability principle was proposed. In order to further enhance the stability of ISF, different dosage of calcium fluoroaluminate was added to ISF specimens whose stability coefficient was tested and change of hydration products was detected by scanning electron microscope (SEM). The outcomes indicated that calcium fluoroaluminate could enhance the stability coefficient of ISF and compact hydration products formed in cell wall of ISF; naturally, the stability principle of ISF was proved right. Based on above-mentioned experimental contents, ISF with stability coefficient of 95% and foam expansion ratio of 5 was prepared, which could sufficiently satisfy field process requirements on plugging air leakage and thermal insulation. Botao Qin, Yi Lu, Fanglei Li, Yuwei Jia, Chao Zhu, and Quanlin Shi Copyright © 2014 Botao Qin et al. All rights reserved. Investigation of Soil Liquefaction Potential around Efteni Lake in Duzce Turkey: Using Empirical Relationships between Shear Wave Velocity and SPT Blow Count (N) Tue, 01 Jul 2014 08:10:29 +0000 Evaluation of the liquefaction potential of a liquefaction-prone area is important for geotechnical earthquake engineering, both for assessment for site selection and for planning and new constructions. The liquefaction potential index for the city of Duzce in northwestern Turkey using the empirical relationships between the Standard Penetration Test (SPT) and the Shear Wave Velocity Test () was investigated in this study. After, values based on SPT blow counts () were obtained from the alluvial soils in the city of Duzce. The liquefaction potential indexes of the soils were determined using the empirical relationships between the Standard Penetration Test (SPT) and the Shear Wave Velocity Test () calculating for a probable earthquake of . In the result of the study, the liquefaction potential index (LPI) values were interpreted and compared evaluating the SPT blow count values obtained from the study area. Based on the empirical relationships assumed for the soils, it was observed that there was not a perfect agreement between the results of the two methods. The liquefaction potential index values using the SPT blow counts were found to be lower than those of the method. Ali Ateş, İnan Keskin, Ermedin Totiç, and Burak Yeşil Copyright © 2014 Ali Ateş et al. All rights reserved. Crack Extension Resistance of Normal-Strength Concrete Subjected to Elevated Temperatures Thu, 26 Jun 2014 00:00:00 +0000 Determination of the residual crack extension resistance curves (-curves) associated with cohesive force distribution on fictitious crack zone of complete fracture process is implemented in present research. The cohesive force distributes according to bilinear softening traction-separation law proposed by Petersson. Totally ten temperatures varying from 20°C to 600°C and the specimen size of  mm with initial-notch depth ratios 0.4 are considered. The load-crack mouth opening displacement curves (P-CMOD) of postfire specimens are obtained by wedge-splitting method from which the stress intensity factor curves (-curves) are calculated. In each temperature, with the distribution of cohesive force along the fracture process zone, the residual fracture toughness () increases with increasing crack length , whereas the -curves decrease with increasing temperatures for the thermal damage induced. The stability analysis on crack propagation demonstrates that when the residual -curve is higher than -curve, the crack propagates steadily; otherwise, the crack propagates unsteadily. Jing Chen and Zhoudao Lu Copyright © 2014 Jing Chen and Zhoudao Lu. All rights reserved. Impact of High Temperature on the Compressive Strength of ECC Wed, 25 Jun 2014 11:27:12 +0000 The influence of different cooling regimes (quenching in water and cooling in air) on the residual mechanical properties of ECC (engineered cementitious composites) exposed to high temperature up to 800°C was discussed in this paper. The specimens quenching in water gained better mechanical properties than the ones cooling in air. The strengthening effect of quenching for specimens subjected to 800°C was more significant than for the ones subjected to 400°C. The microstructural characterization is examined before and after exposure to fire deterioration by using scanning electron microscopy. Results from the microtest well explained the mechanical properties variation of postfire specimens. Xingyan Shang and Zhoudao Lu Copyright © 2014 Xingyan Shang and Zhoudao Lu. All rights reserved. Tissue Engineering of Muscles and Cartilages Using Polyelectrolyte Hydrogels Wed, 25 Jun 2014 10:34:47 +0000 The prevalent nature of osteoarthritis that causes the erosion of joint surfaces and loss of mobility and muscle dystrophy that weakens the musculoskeletal system and hampers locomotion underlies the importance of developing functional replacement or regeneration of muscle and cartilage tissues. Polyelectrolyte gels have high potential as cellular scaffolds due to characteristic properties similar to biological matrixes. A number of in vitro and in vivo studies demonstrated that polyelectrolyte gels are useful for replacement and regeneration of muscle and cartilage tissues. In addition, it was also found that polyelectrolyte gels have high biocompatibility, durability, and resistance to biodegradation. Moreover, polyelectrolyte gels can overcome their drawbacks of mechanical behavior by introducing double network into the gel. This paper reviews the current status and recent progress of polyelectrolyte gel-based tissue engineering for repairs of muscle and cartilage tissues. Hyuck Joon Kwon Copyright © 2014 Hyuck Joon Kwon. All rights reserved. Friction Stir Spot Welding: A Review on Joint Macro- and Microstructure, Property, and Process Modelling Wed, 25 Jun 2014 08:15:06 +0000 Friction stir spot welding (FSSW) is a very useful variant of the conventional friction stir welding (FSW), which shows great potential to be a replacement of single-point joining processes like resistance spot welding and riveting. There have been many reports and some industrial applications about FSSW. Based on the open literatures, the process features and variants, macro- and microstructural characteristics, and mechanical properties of the resultant joints and numerical simulations of the FSSW process were summarized. In addition, some applications of FSSW in aerospace, aviation, and automobile industries were also reviewed. Finally, the current problems and issues that existed in FSSW were indicated. X. W. Yang, T. Fu, and W. Y. Li Copyright © 2014 X. W. Yang et al. All rights reserved. Nanotechnology for Energy and Environment Wed, 25 Jun 2014 05:50:52 +0000 J. M. P. Q. Delgado, Andreas Öchsner, and A. G. Barbosa de Lima Copyright © 2014 J. M. P. Q. Delgado et al. All rights reserved. Nanocomposite Thin Film of Poly(3-aminobenzoic acid) and Multiwalled Carbon Nanotubes Fabricated through an Electrochemical Method Tue, 24 Jun 2014 00:00:00 +0000 The composite thin films of poly(3-aminobenzoic acid) (PABA) and multiwalled carbon nanotubes (MWNTs) are successfully fabricated through an electrochemical method. The composite mixtures containing 50 mM of 3-aminobenzoic acid with various concentrations of MWNTs (1.0, 2.5, 5.0, 7.5, and 10 mg/mL) in 0.5 M H2SO4 were prepared and used in this study. Cyclic voltammetry (CV) was used for fabrication and monitoring the electropolymerization of the composite thin films with potential range of 0 to 1100 mV for 5 cycles at scan rate of 20 mV/s on indium tin oxide- (ITO)-coated glass substrate. UV-vis absorption spectroscopy, atomic force microscopy (AFM), and scanning electron microscopy (SEM) techniques were employed to characterize the obtained composite thin films. It was found that MWNTs can enhance the peak current of CV traces of the PABA/MWNTs composite thin films without affecting the UV-vis absorption spectra. The surface morphology of the thin films can be studied using AFM and SEM techniques. Paphawadee Netsuwan, Wirat Chaisu, Sukon Phanichphant, and Saengrawee Sriwichai Copyright © 2014 Paphawadee Netsuwan et al. All rights reserved.