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Materials, Volume 9, Issue 4 (April 2016)

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Cover Story (view full-size image) Photo-electrolysis is a promising strategy to exploit solar energy aimed at producing clean fuels [...] Read more.
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Open AccessArticle Mechanics Model for Simulating RC Hinges under Reversed Cyclic Loading
Materials 2016, 9(4), 305; https://doi.org/10.3390/ma9040305
Received: 18 February 2016 / Revised: 13 April 2016 / Accepted: 19 April 2016 / Published: 22 April 2016
Cited by 2 | PDF Full-text (4470 KB) | HTML Full-text | XML Full-text
Abstract
Describing the moment rotation (M/θ) behavior of reinforced concrete (RC) hinges is essential in predicting the behavior of RC structures under severe loadings, such as under cyclic earthquake motions and blast loading. The behavior of RC hinges is defined by localized slip or
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Describing the moment rotation (M/θ) behavior of reinforced concrete (RC) hinges is essential in predicting the behavior of RC structures under severe loadings, such as under cyclic earthquake motions and blast loading. The behavior of RC hinges is defined by localized slip or partial interaction (PI) behaviors in both the tension and compression region. In the tension region, slip between the reinforcement and the concrete defines crack spacing, crack opening and closing, and tension stiffening. While in the compression region, slip along concrete to concrete interfaces defines the formation and failure of concrete softening wedges. Being strain-based, commonly-applied analysis techniques, such as the moment curvature approach, cannot directly simulate these PI behaviors because they are localized and displacement based. Therefore, strain-based approaches must resort to empirical factors to define behaviors, such as tension stiffening and concrete softening hinge lengths. In this paper, a displacement-based segmental moment rotation approach, which directly simulates the partial interaction behaviors in both compression and tension, is developed for predicting the M/θ response of an RC beam hinge under cyclic loading. Significantly, in order to develop the segmental approach, a partial interaction model to predict the tension stiffening load slip relationship between the reinforcement and the concrete is developed. Full article
(This article belongs to the Section Structure Analysis and Characterization)
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Open AccessArticle Evaluation of Functionalized Porous Titanium Implants for Enhancing Angiogenesis in Vitro
Materials 2016, 9(4), 304; https://doi.org/10.3390/ma9040304
Received: 3 March 2016 / Revised: 14 April 2016 / Accepted: 18 April 2016 / Published: 22 April 2016
Cited by 2 | PDF Full-text (5045 KB) | HTML Full-text | XML Full-text
Abstract
Implant constructs supporting angiogenesis are favorable for treating critically-sized bone defects, as ingrowth of capillaries towards the center of large defects is often insufficient. Consequently, the insufficient nutritional supply of these regions leads to impaired bone healing. Implants with specially designed angiogenic supporting
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Implant constructs supporting angiogenesis are favorable for treating critically-sized bone defects, as ingrowth of capillaries towards the center of large defects is often insufficient. Consequently, the insufficient nutritional supply of these regions leads to impaired bone healing. Implants with specially designed angiogenic supporting geometry and functionalized with proangiogenic cytokines can enhance angiogenesis. In this study, Vascular Endothelial Growth Factor (VEGF) and High Mobility Group Box 1 (HMGB1) were used for incorporation into poly-ε-caprolactone (PCL)-coated porous titanium implants. Bioactivity of released factors and influence on angiogenesis of functionalized implants were evaluated using a migration assay and angiogenesis assays. Both implants released angiogenic factors, inducing migration of endothelial cells. Also, VEGF-functionalized PCL-coated titanium implants enhanced angiogenesis in vitro. Both factors were rapidly released in high doses from the implant coating during the first 72 h. Full article
(This article belongs to the Special Issue Materials for Hard and Soft Tissue Engineering: Novel Approaches)
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Open AccessFeature PaperReview A Review on Grafting of Biofibers for Biocomposites
Materials 2016, 9(4), 303; https://doi.org/10.3390/ma9040303
Received: 14 March 2016 / Revised: 14 April 2016 / Accepted: 18 April 2016 / Published: 22 April 2016
Cited by 17 | PDF Full-text (2078 KB) | HTML Full-text | XML Full-text
Abstract
A recent increase in the use of biofibers as low-cost and renewable reinforcement for the polymer biocomposites has been seen globally. Biofibers are classified into: lignocellulosic fibers (i.e., cellulose, wood and natural fibers), nanocellulose (i.e., cellulose nanocrystals and cellulose
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A recent increase in the use of biofibers as low-cost and renewable reinforcement for the polymer biocomposites has been seen globally. Biofibers are classified into: lignocellulosic fibers (i.e., cellulose, wood and natural fibers), nanocellulose (i.e., cellulose nanocrystals and cellulose nanofibrils), and bacterial cellulose, while polymer matrix materials can be petroleum based or bio-based. Green biocomposites can be produced using both biobased fibers and polymers. Incompatibility between the hydrophilic biofibers and hydrophobic polymer matrix can cause performance failure of resulting biocomposites. Diverse efforts have focused on the modification of biofibers in order to improve the performances of biocomposites. “Grafting” copolymerization strategy can render the advantages of biofiber and impart polymer properties onto it and the performance of biocomposites can be tuned through changing grafting parameters. This review presents a short overview of various “grafting” methods which can be directly or potentially employed to enhance the interaction between biofibers and a polymer matrix for biocomposites. Major grafting techniques, including ring opening polymerization, grafting via coupling agent and free radical induced grafting, have been discussed. Improved properties such as mechanical, thermal, and water resistance have provided grafted biocomposites with new opportunities for applications in specific industries. Full article
(This article belongs to the Special Issue Bio- and Natural-Fiber Composites)
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Open AccessArticle In Vitro Evaluation and Mechanism Analysis of the Fiber Shedding Property of Textile Pile Debridement Materials
Materials 2016, 9(4), 302; https://doi.org/10.3390/ma9040302
Received: 1 March 2016 / Revised: 7 April 2016 / Accepted: 18 April 2016 / Published: 22 April 2016
Cited by 1 | PDF Full-text (9033 KB) | HTML Full-text | XML Full-text
Abstract
Fiber shedding is a critical problem in biomedical textile debridement materials, which leads to infection and impairs wound healing. In this work, single fiber pull-out test was proposed as an in vitro evaluation for the fiber shedding property of a textile pile debridement
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Fiber shedding is a critical problem in biomedical textile debridement materials, which leads to infection and impairs wound healing. In this work, single fiber pull-out test was proposed as an in vitro evaluation for the fiber shedding property of a textile pile debridement material. Samples with different structural design (pile densities, numbers of ground yarns and coating times) were prepared and estimated under this testing method. Results show that single fiber pull-out test offers an appropriate in vitro evaluation for the fiber shedding property of textile pile debridement materials. Pull-out force for samples without back-coating exhibited a slight escalating trend with the supplement in pile density and number of ground yarn plies, while back-coating process significantly raised the single fiber pull-out force. For fiber shedding mechanism analysis, typical pull-out behavior and failure modes of the single fiber pull-out test were analyzed in detail. Three failure modes were found in this study, i.e., fiber slippage, coating point rupture and fiber breakage. In summary, to obtain samples with desirable fiber shedding property, fabric structural design, preparation process and raw materials selection should be taken into full consideration. Full article
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Open AccessFeature PaperArticle Shape-Dependent Single-Electron Levels for Au Nanoparticles
Materials 2016, 9(4), 301; https://doi.org/10.3390/ma9040301
Received: 28 February 2016 / Revised: 8 April 2016 / Accepted: 12 April 2016 / Published: 21 April 2016
Cited by 3 | PDF Full-text (1743 KB) | HTML Full-text | XML Full-text
Abstract
The shape of metal nanoparticles has a crucial role in their performance in heterogeneous catalysis as well as photocatalysis. We propose a method of determining the shape of nanoparticles based on measurements of single-electron quantum levels. We first consider nanoparticles in two shapes
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The shape of metal nanoparticles has a crucial role in their performance in heterogeneous catalysis as well as photocatalysis. We propose a method of determining the shape of nanoparticles based on measurements of single-electron quantum levels. We first consider nanoparticles in two shapes of high symmetry: cube and sphere. We then focus on Au nanoparticles in three characteristic shapes that can be found in metal/inorganic or metal/organic compounds routinely used in catalysis and photocatalysis. We describe the methodology we use to solve the Schrödinger equation for arbitrary nanoparticle shape. The method gives results that agree well with analytical solutions for the high-symmetry shapes. When we apply our method in realistic gold nanoparticle models, which are obtained from Wulff construction based on first principles calculations, the single-electron levels and their density of states exhibit distinct shape-dependent features. Results for clean-surface nanoparticles are closer to those for cubic particles, while CO-covered nanoparticles have energy levels close to those of a sphere. Thiolate-covered nanoparticles with multifaceted polyhedral shape have distinct levels that are in between those for sphere and cube. We discuss how shape-dependent electronic structure features could be identified in experiments and thus guide catalyst design. Full article
(This article belongs to the Special Issue Advancement of Photocatalytic Materials 2016)
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Open AccessArticle Temperature-Driven Structural and Morphological Evolution of Zinc Oxide Nano-Coalesced Microstructures and Its Defect-Related Photoluminescence Properties
Materials 2016, 9(4), 300; https://doi.org/10.3390/ma9040300
Received: 4 January 2016 / Revised: 19 March 2016 / Accepted: 15 April 2016 / Published: 20 April 2016
Cited by 11 | PDF Full-text (4992 KB) | HTML Full-text | XML Full-text
Abstract
In this paper, we address the synthesis of nano-coalesced microstructured zinc oxide thin films via a simple thermal evaporation process. The role of synthesis temperature on the structural, morphological, and optical properties of the prepared zinc oxide samples was deeply investigated. The obtained
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In this paper, we address the synthesis of nano-coalesced microstructured zinc oxide thin films via a simple thermal evaporation process. The role of synthesis temperature on the structural, morphological, and optical properties of the prepared zinc oxide samples was deeply investigated. The obtained photoluminescence and X-ray photoelectron spectroscopy outcomes will be used to discuss the surface structure defects of the prepared samples. The results indicated that the prepared samples are polycrystalline in nature, and the sample prepared at 700 °C revealed a tremendously c-axis oriented zinc oxide. The temperature-driven morphological evolution of the zinc oxide nano-coalesced microstructures was perceived, resulting in transformation of quasi-mountain chain-like to pyramidal textured zinc oxide with increasing the synthesis temperature. The results also impart that the sample prepared at 500 °C shows a higher percentage of the zinc interstitial and oxygen vacancies. Furthermore, the intensity of the photoluminescence emission in the ultraviolet region was enhanced as the heating temperature increased from 500 °C to 700 °C. Lastly, the growth mechanism of the zinc oxide nano-coalesced microstructures is discussed according to the reaction conditions. Full article
(This article belongs to the Section Structure Analysis and Characterization)
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Open AccessArticle Microwave Synthesized ZnO Nanorod Arrays for UV Sensors: A Seed Layer Annealing Temperature Study
Materials 2016, 9(4), 299; https://doi.org/10.3390/ma9040299
Received: 27 February 2016 / Revised: 6 April 2016 / Accepted: 15 April 2016 / Published: 20 April 2016
Cited by 13 | PDF Full-text (5158 KB) | HTML Full-text | XML Full-text
Abstract
The present work reports the influence of zinc oxide (ZnO) seed layer annealing temperature on structural, optical and electrical properties of ZnO nanorod arrays, synthesized by hydrothermal method assisted by microwave radiation, to be used as UV sensors. The ZnO seed layer was
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The present work reports the influence of zinc oxide (ZnO) seed layer annealing temperature on structural, optical and electrical properties of ZnO nanorod arrays, synthesized by hydrothermal method assisted by microwave radiation, to be used as UV sensors. The ZnO seed layer was produced using the spin-coating method and several annealing temperatures, ranging from 100 to 500 °C, have been tested. X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and spectrophotometry measurements have been used to investigate the structure, morphology, and optical properties variations of the produced ZnO nanorod arrays regarding the seed layer annealing temperatures employed. After the growth of ZnO nanorod arrays, the whole structure was tested as UV sensors, showing an increase in the sensitivity with the increase of seed layer annealing temperature. The UV sensor response of ZnO nanorod arrays produced with the seed layer annealed temperature of 500 °C was 50 times superior to the ones produced with a seed layer annealed at 100 °C. Full article
(This article belongs to the Special Issue Microwave Materials Processing)
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Open AccessArticle Mechanical Properties, Short Time Creep, and Fatigue of an Austenitic Steel
Materials 2016, 9(4), 298; https://doi.org/10.3390/ma9040298
Received: 26 February 2016 / Revised: 8 April 2016 / Accepted: 15 April 2016 / Published: 20 April 2016
Cited by 3 | PDF Full-text (4341 KB) | HTML Full-text | XML Full-text
Abstract
The correct choice of a material in the process of structural design is the most important task. This study deals with determining and analyzing the mechanical properties of the material, and the material resistance to short-time creep and fatigue. The material under consideration
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The correct choice of a material in the process of structural design is the most important task. This study deals with determining and analyzing the mechanical properties of the material, and the material resistance to short-time creep and fatigue. The material under consideration in this investigation is austenitic stainless steel X6CrNiTi18-10. The results presenting ultimate tensile strength and 0.2 offset yield strength at room and elevated temperatures are displayed in the form of engineering stress-strain diagrams. Besides, the creep behavior of the steel is presented in the form of creep curves. The material is consequently considered to be creep resistant at temperatures of 400 °C and 500 °C when subjected to a stress which is less than 0.9 of the yield strength at the mentioned temperatures. Even when the applied stress at a temperature of 600 °C is less than 0.5 of the yield strength, the steel may be considered as resistant to creep. Cyclic tensile fatigue tests were carried out at stress ratio R = 0.25 using a servo-pulser machine and the results were recorded. The analysis shows that the stress level of 434.33 MPa can be adopted as a fatigue limit. The impact energy was also determined and the fracture toughness assessed. Full article
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Open AccessFeature PaperArticle Polyelectrolyte-Functionalized Nanofiber Mats Control the Collection and Inactivation of Escherichia coli
Materials 2016, 9(4), 297; https://doi.org/10.3390/ma9040297
Received: 30 December 2015 / Revised: 28 March 2016 / Accepted: 12 April 2016 / Published: 19 April 2016
Cited by 4 | PDF Full-text (3217 KB) | HTML Full-text | XML Full-text
Abstract
Quantifying the effect that nanofiber mat chemistry and hydrophilicity have on microorganism collection and inactivation is critical in biomedical applications. In this study, the collection and inactivation of Escherichia coli K12 was examined using cellulose nanofiber mats that were surface-functionalized using three polyelectrolytes:
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Quantifying the effect that nanofiber mat chemistry and hydrophilicity have on microorganism collection and inactivation is critical in biomedical applications. In this study, the collection and inactivation of Escherichia coli K12 was examined using cellulose nanofiber mats that were surface-functionalized using three polyelectrolytes: poly (acrylic acid) (PAA), chitosan (CS), and polydiallyldimethylammonium chloride (pDADMAC). The polyelectrolyte functionalized nanofiber mats retained the cylindrical morphology and average fiber diameter (~0.84 µm) of the underlying cellulose nanofibers. X-ray photoelectron spectroscopy (XPS) and contact angle measurements confirmed the presence of polycations or polyanions on the surface of the nanofiber mats. Both the control cellulose and pDADMAC-functionalized nanofiber mats exhibited a high collection of E. coli K12, which suggests that mat hydrophilicity may play a larger role than surface charge on cell collection. While the minimum concentration of polycations needed to inhibit E. coli K12 was 800 µg/mL for both CS and pDADMAC, once immobilized, pDADMAC-functionalized nanofiber mats exhibited a higher inactivation of E. coli K12, (~97%). Here, we demonstrate that the collection and inactivation of microorganisms by electrospun cellulose nanofiber mats can be tailored through a facile polyelectrolyte functionalization process. Full article
(This article belongs to the Special Issue Electrospun Materials)
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Open AccessFeature PaperArticle Spin-Coated vs. Electrodeposited Mn Oxide Films as Water Oxidation Catalysts
Materials 2016, 9(4), 296; https://doi.org/10.3390/ma9040296
Received: 31 December 2015 / Revised: 11 April 2016 / Accepted: 13 April 2016 / Published: 19 April 2016
Cited by 8 | PDF Full-text (1943 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Manganese oxides (MnOx), being active, inexpensive and low-toxicity materials, are considered promising water oxidation catalysts (WOCs). This work reports the preparation and the physico-chemical and electrochemical characterization of spin-coated (SC) films of commercial Mn2O3, Mn3O
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Manganese oxides (MnOx), being active, inexpensive and low-toxicity materials, are considered promising water oxidation catalysts (WOCs). This work reports the preparation and the physico-chemical and electrochemical characterization of spin-coated (SC) films of commercial Mn2O3, Mn3O4 and MnO2 powders. Spin coating consists of few preparation steps and employs green chemicals (i.e., ethanol, acetic acid, polyethylene oxide and water). To the best of our knowledge, this is the first time SC has been used for the preparation of stable powder-based WOCs electrodes. For comparison, MnOx films were also prepared by means of electrodeposition (ED) and tested under the same conditions, at neutral pH. Particular interest was given to α-Mn2O3-based films, since Mn (III) species play a crucial role in the electrocatalytic oxidation of water. To this end, MnO2-based SC and ED films were calcined at 500 °C, in order to obtain the desired α-Mn2O3 crystalline phase. Electrochemical impedance spectroscopy (EIS) measurements were performed to study both electrode charge transport properties and electrode–electrolyte charge transfer kinetics. Long-term stability tests and oxygen/hydrogen evolution measurements were also made on the highest-performing samples and their faradaic efficiencies were quantified, with results higher than 95% for the Mn2O3 SC film, finally showing that the SC technique proposed here is a simple and reliable method to study the electrocatalytic behavior of pre-synthesized WOCs powders. Full article
(This article belongs to the Special Issue Electrode Materials)
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Open AccessArticle Residual Mechanical Properties of Concrete Made with Crushed Clay Bricks and Roof Tiles Aggregate after Exposure to High Temperatures
Materials 2016, 9(4), 295; https://doi.org/10.3390/ma9040295
Received: 30 January 2016 / Revised: 10 April 2016 / Accepted: 12 April 2016 / Published: 19 April 2016
Cited by 3 | PDF Full-text (3914 KB) | HTML Full-text | XML Full-text
Abstract
This paper presents the residual mechanical properties of concrete made with crushed bricks and clay roof tile aggregates after exposure to high temperatures. One referent mixture and eight mixtures with different percentages of replacement of natural aggregate by crushed bricks and roof tiles
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This paper presents the residual mechanical properties of concrete made with crushed bricks and clay roof tile aggregates after exposure to high temperatures. One referent mixture and eight mixtures with different percentages of replacement of natural aggregate by crushed bricks and roof tiles are experimentally tested. The properties of the concrete were measured before and after exposure to 200, 400, 600 and 800 °C. In order to evaluate the basic residual mechanical properties of concrete with crushed bricks and roof tiles after exposure to high temperatures, ultrasonic pulse velocity is used as a non-destructive test method and the results are compared with those of a destructive method for validation. The mixture with the highest percentage of replacement of natural aggregate by crushed brick and roof tile aggregate has the best physical, mechanical, and thermal properties for application of such concrete in precast concrete elements exposed to high temperatures. Full article
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Open AccessArticle Ultrasonic Monitoring of Setting and Strength Development of Ultra-High-Performance Concrete
Materials 2016, 9(4), 294; https://doi.org/10.3390/ma9040294
Received: 22 March 2016 / Revised: 6 April 2016 / Accepted: 13 April 2016 / Published: 19 April 2016
Cited by 2 | PDF Full-text (2977 KB) | HTML Full-text | XML Full-text
Abstract
In this study, the setting and tensile strength development of ultra-high-performance concrete (UHPC) at a very early age was investigated by performing the penetration resistance test (ASTM C403), as well as the direct tensile test using the newly developed test apparatus, and taking
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In this study, the setting and tensile strength development of ultra-high-performance concrete (UHPC) at a very early age was investigated by performing the penetration resistance test (ASTM C403), as well as the direct tensile test using the newly developed test apparatus, and taking ultrasonic pulse velocity (UPV) measurements. In order to determine the optimum surface treatment method for preventing rapid surface drying of UHPC, four different methods were examined: plastic sheet, curing cover, membrane-forming compound, and paraffin oil. Based on the test results, the use of paraffin oil was found to be the best choice for measuring the penetration resistance and the UPV, and attaching the plastic sheet to the exposed surface was considered to be a simple method for preventing the rapid surface drying of UHPC elements. An S-shaped tensile strength development at a very early age (before 24 h) was experimentally obtained, and it was predicted by a power function of UPV. Lastly, the addition of shrinkage-reducing and expansive admixtures resulted in more rapid development of penetration resistance and UPV of UHPC. Full article
(This article belongs to the Section Advanced Composites)
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Open AccessArticle Study of Charge Carrier Transport in GaN Sensors
Materials 2016, 9(4), 293; https://doi.org/10.3390/ma9040293
Received: 17 February 2016 / Revised: 14 March 2016 / Accepted: 12 April 2016 / Published: 18 April 2016
Cited by 5 | PDF Full-text (1840 KB) | HTML Full-text | XML Full-text
Abstract
Capacitor and Schottky diode sensors were fabricated on GaN material grown by hydride vapor phase epitaxy and metal-organic chemical vapor deposition techniques using plasma etching and metal deposition. The operational characteristics of these devices have been investigated by profiling current transients and by
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Capacitor and Schottky diode sensors were fabricated on GaN material grown by hydride vapor phase epitaxy and metal-organic chemical vapor deposition techniques using plasma etching and metal deposition. The operational characteristics of these devices have been investigated by profiling current transients and by comparing the experimental regimes of the perpendicular and parallel injection of excess carrier domains. Profiling of the carrier injection location allows for the separation of the bipolar and the monopolar charge drift components. Carrier mobility values attributed to the hydride vapor phase epitaxy (HVPE) GaN material have been estimated as μe = 1000 ± 200 cm2/Vs for electrons, and μh = 400 ± 80 cm2/Vs for holes, respectively. Current transients under injection of the localized and bulk packets of excess carriers have been examined in order to determine the surface charge formation and polarization effects. Full article
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Open AccessArticle Research on Glass Frit Deposition Based on the Electrospray Process
Materials 2016, 9(4), 292; https://doi.org/10.3390/ma9040292
Received: 22 February 2016 / Revised: 1 April 2016 / Accepted: 6 April 2016 / Published: 18 April 2016
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Abstract
In this paper, the electrospray technology is used to easily deposit the glass frit into patterns at a micro-scale level. First, far-field electrospray process was carried out with a mixture of glass frit in the presence of ethanol. A uniform, smooth, and dense
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In this paper, the electrospray technology is used to easily deposit the glass frit into patterns at a micro-scale level. First, far-field electrospray process was carried out with a mixture of glass frit in the presence of ethanol. A uniform, smooth, and dense glass frit film was obtained, verifying that the electrospray technology was feasible. Then, the distance between the nozzle and the substrate was reduced to 2 mm to carry out near-field electrospray. The experimental process was improved by setting the range of the feed rate of the substrate to match both the concentration and the flow rate of the solution. Spray diameter could be less at the voltage of 2 kV, in which the glass frit film was expected to reach the minimum line width. A uniform glass frit film with a line width within the range of 400–500 μm was prepared when the speed of the substrate was 25 mm/s. It indicates that electrospray is an efficient technique for the patterned deposition of glass frit in wafer-level hermetic encapsulation. Full article
(This article belongs to the Section Manufacturing Processes and Systems)
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Open AccessArticle Development of a Tomography Technique for Assessment of the Material Condition of Concrete Using Optimized Elastic Wave Parameters
Materials 2016, 9(4), 291; https://doi.org/10.3390/ma9040291
Received: 7 December 2015 / Revised: 6 April 2016 / Accepted: 7 April 2016 / Published: 16 April 2016
Cited by 2 | PDF Full-text (33296 KB) | HTML Full-text | XML Full-text
Abstract
Concrete is the most ubiquitous construction material. Apart from the fresh and early age properties of concrete material, its condition during the structure life span affects the overall structural performance. Therefore, development of techniques such as non-destructive testing which enable the investigation of
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Concrete is the most ubiquitous construction material. Apart from the fresh and early age properties of concrete material, its condition during the structure life span affects the overall structural performance. Therefore, development of techniques such as non-destructive testing which enable the investigation of the material condition, are in great demand. Tomography technique has become an increasingly popular non-destructive evaluation technique for civil engineers to assess the condition of concrete structures. In the present study, this technique is investigated by developing reconstruction procedures utilizing different parameters of elastic waves, namely the travel time, wave amplitude, wave frequency, and Q-value. In the development of algorithms, a ray tracing feature was adopted to take into account the actual non-linear propagation of elastic waves in concrete containing defects. Numerical simulation accompanied by experimental verifications of wave motion were conducted to obtain wave propagation profiles in concrete containing honeycomb as a defect and in assessing the tendon duct filling of pre-stressed concrete (PC) elements. The detection of defects by the developed tomography reconstruction procedures was evaluated and discussed. Full article
(This article belongs to the Special Issue Image Analysis and Processing for Cement-based Materials)
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