Search

Abstract: An ultraselective and ultrasensitive trimethylamine (TMA) sensor was achieved using MoO3 nanoplates-prepared by ultrasonic spray pyrolysis followed by a heat treatment at 450°C. The small and thin MoO3 nanoplates with gas-accessible structures showed an unusually high response to 5ppm TMA (ratio of resistance to air and gas=373.74) at 300°C with detection limit as low as 45ppb. Moreover, the ratios of the cross-responses to interfering gases (i.e., 5ppm C2H5OH, CO, CH4, C3H8, H2, and NO2) to the response to 5ppm TMA were extremely low (0.008–0.016). The source of the ultraselective and highly sensitive detection of TMA with negligible interference from other gases is discussed with respect to the acid/base properties, size, and morphology of the MoO3 sensing materials. [Copyright &y& Elsevier]

Abstract: WO3 hollow spheres were prepared by ultrasonic spray pyrolysis of a citric-acid-containing precursor solution, and their trimethylamine-sensing characteristics were investigated. The WO3 hollow spheres showed a high response to 5ppm of trimethylamine (R a/R g =56.9, R a: resistance in air, R g: resistance in gas) with low cross-responses to 5ppm C2H5OH, CO, CH4, C3H8, H2, NH3, and NO2. The high gas response observed was explained by the effective electron depletion of small primary particles and the enhanced gas accessibility of hollow structures with thin and porous shells. The enhanced trimethylamine selectivity was discussed in terms of the interaction between basic analyte gas and acidic sensing materials. [Copyright &y& Elsevier]

Abstract: Constrained optimization is a major real-world problem. Constrained optimization problems consist of an objective function subjected to both linear and nonlinear constraints. Here a constraint handling procedure based on the fitness priority-based ranking method (FPBRM) is proposed. It is embedded into a harmony search (HS) algorithm that allows it to satisfy constraints. The HS algorithm is conceptualized using the musical process of searching for a perfect state of harmony. Here, the original heuristic HS was improved by combining both improved and global-best methods along with the FPBRM. The resulting modified harmony search (MHS) was then compared with the original HS technique and other optimization methods for several test problems. [Copyright &y& Elsevier]

Abstract: The effects of a V2O5 additive on the low-temperature sintering and ionic conductivity of strontium- and magnesium-doped lanthanum gallate (LSGM: La0.8Sr0.2Ga0.8Mg0.2O2.8) are studied. The LSGM powders prepared by the glycine nitrate method are mixed with 0.5–2at.% of VO5/2 and then sintered at 1100–1400°C in air for 4h. The apparent density and phase purity of the LSGM specimens are increased with increasing sintering temperature and VO5/2 concentration due to the enhanced sintering and mass transfer via the intergranular liquid phase. The 1at.% VO5/2-doped LSGM specimen sintered at 1300°C exhibits a high oxide ion conductivity of ∼0.027Scm−1 at 700°C over a wide range of oxygen partial pressure (), thereby demonstrating its potential as a useful electrolyte for anode-supported solid oxide fuel cells (SOFCs) without the requirement for any buffer layer between the electrolyte and anode. [ABSTRACT FROM AUTHOR]

Abstract: The effects of 14 different metal-oxide additives (metal=Mn, Fe, Co, Ni, Cu, B, Li, V, Zn, Si, Ca, Al, Bi, and Ba) on the sintering, phase purity, and electrical properties of strontium- and magnesium-doped lanthanum gallate (LSGM) are studied. The density, phase purity, and electrical conductivity depend closely on the sintering aids and sintering temperatures. The addition of V, Zn, Si, Co, and Fe improves the densification, phase purity, and electrical conductivity, with V showing the most promising effect on the low-temperature sintering of the phase-pure LSGM specimen with high conductivity. [Copyright &y& Elsevier]

Abstract: This paper presents a novel method to design a desired noise barrier using the global optimization of a simulated annealing (SA) algorithm. This method focuses on minimizing the barrier dimensions, which are related to material and construction costs, as well as satisfying the target sound pressure levels at receiver points on the condition of traffic noise. Various examples are presented to evaluate the optimized barrier dimensions according to given traffic noise sources, ground topography, surface conditions, and the influence of different receiver positions. As a result, a robust method is found that can determine optimized barrier configurations and dimensions that yield cost reductions. [Copyright &y& Elsevier]

Abstract: This paper proposes MgO as a new scavenger material that can mitigate the harmful effects of SiO2 impurity on the grain-boundary conduction in 10mol.% gadolinia-doped ceria (GDC). The addition of 0.3–10mol.% of MgO resulted in an up to ∼45-fold increase in the grain-boundary conduction of a GDC specimen containing 500ppm of SiO2 impurity. The solubility limit of MgO in GDC was found to be as low as ∼0.1mol.% and most of the MgO existed as a second phase. Electron energy-loss spectroscopic analysis indicated the formation of forsterite (Mg2SiO4), due to a reaction between MgO and the siliceous intergranular phase, to be the scavenging mechanism. [Copyright &y& Elsevier]

Abstract: The vibration and buckling of an infinite shear beam-column, which considers the effects of shear and the axial compressive force, resting on an elastic foundation have been investigated when the system is subjected to moving loads of either constant amplitude or harmonic amplitude variation with a constant advance velocity. Damping of a linear hysteretic nature for the foundation was considered. Formulations in the transformed field domains of time and moving space were developed, and the response to moving loads of constant amplitude and the steady-state response to moving harmonic loads were obtained using a Fourier transform. Analyses were performed to examine how the shear deformation of the beam and the axial compression affect the stability and vibration of the system, and to investigate the effects of various parameters, such as the load velocity, load frequency, shear rigidity, and damping, on the deflected shape, maximum displacement, and critical values of the velocity, frequency, and axial compression. Expressions to predict the critical (resonance) velocity, critical frequency, and axial buckling force were proposed. [Copyright &y& Elsevier]

Abstract: The preferences of customers change over time. However, existing collaborative filtering (CF) systems are static, since they only incorporate information regarding whether a customer buys a product during a certain period and do not make use of the purchase sequences of customers. Therefore, the quality of the recommendations of the typical CF could be improved through the use of information on such sequences. In this study, we propose a new methodology for enhancing the quality of CF recommendation that uses customer purchase sequences. The proposed methodology is applied to a large department store in Korea and compared to existing CF techniques. Various experiments using real-world data demonstrate that the proposed methodology provides higher quality recommendations than do typical CF techniques, with better performance, especially with regard to heavy users. [Copyright &y& Elsevier]

In this paper, we present a similar product finding algorithm for the collaborative business companies that share the product taxonomy table and have exchangeable products information. The main idea of the proposed algorithm is to compute the aggregated utility ranges over specification values of products in the same product class of the companies and find similar ones between the products. Experimental results from a laboratory application are provided in terms of user satisfaction rates. Their comparative implications with a distance measure-based recommendation algorithm are suggested. The experiment confirmed that our algorithm could be used as a solution for similar product recommendation when a buyer''s residence site was different from a receiver''s one and the buyer had his/her own incomplete information about the weights of product specifications. [Copyright &y& Elsevier]

The rapid growth of e-commerce has caused product overload where customers on the Web are no longer able to effectively choose the products they are exposed to. To overcome the product overload of online shoppers, a variety of recommendation methods have been developed. Collaborative filtering (CF) is the most successful recommendation method, but its widespread use has exposed some well-known limitations, such as sparsity and scalability, which can lead to poor recommendations. This paper proposes a recommendation methodology based on Web usage mining, and product taxonomy to enhance the recommendation quality and the system performance of current CF-based recommender systems. Web usage mining populates the rating database by tracking customers'' shopping behaviors on the Web, thereby leading to better quality recommendations. The product taxonomy is used to improve the performance of searching for nearest neighbors through dimensionality reduction of the rating database. Several experiments on real e-commerce data show that the proposed methodology provides higher quality recommendations and better performance than other CF methodologies. [Copyright &y& Elsevier]

A personalized product recommendation is an enabling mechanism to overcome information overload occurred when shopping in an Internet marketplace. Collaborative filtering has been known to be one of the most successful recommendation methods, but its application to e-commerce has exposed well-known limitations such as sparsity and scalability, which would lead to poor recommendations. This paper suggests a personalized recommendation methodology by which we are able to get further effectiveness and quality of recommendations when applied to an Internet shopping mall. The suggested methodology is based on a variety of data mining techniques such as web usage mining, decision tree induction, association rule mining and the product taxonomy. For the evaluation of the methodology, we implement a recommender system using intelligent agent and data warehousing technologies. [Copyright &y& Elsevier]

Abstract: The combined heat and power economic dispatch (CHPED) problem enhances the conversion efficiency from fossil fuels into electricity, eventually reducing the green house gas. However, the optimization formulation for a popular bench-mark example has not properly considered the constraint of heat-power feasible operating region so far. Thus, this study proposes a novel technique to consider the non-convex heat-power feasible region in the CHPED problem more accurately. This study divides the non-convex operating region into two convex operating sub-regions by introducing two binary variables indicating the searching region. In addition, more accurate results and better demand constraints are proposed to more fairly compare the results for this bench-mark problem in the future. [Copyright &y& Elsevier]

Abstract: A range of La0.75Sr0.25Cr0.5Mn0.5O3−δ (LSCM) powders is prepared by the carbonate coprecipitation method for use as anodes in solid oxide fuel cells. The supersaturation ratio (R =[(NH4)2CO3]/([La3+]+[Sr2+]+[Cr3+]+[Mn2+])) during the coprecipitation determines the relative compositions of La, Sr, Cr, and Mn. The composition of the precursor approaches the stoichiometric one at the supersaturation range of 4≤ R ≤12.5, whereas Sr and Mn components are deficient at R <4 and excessive at R =25. The fine and phase-pure LSCM powders are prepared by heat treatment at very low temperature (1000°C) at R =7.5 and 12.5. By contrast, the solid-state reaction requires a higher heat-treatment temperature (1400°C). The catalytic activity of the LSCM electrodes is enhanced by using carbonate-derived powders to manipulate the electrode microstructures. [Copyright &y& Elsevier]

Abstract: Dependence of the electrical properties on grain-boundary plane orientation is examined by a combination of high-resolution transmission electron microscopy, impedance spectroscopy, and electron energy-loss spectrometry using two kinds of SrTiO3 Σ5 ([100]/36.8°) bicrystalline grain boundaries: symmetric (310) (18.4°/18.4°) and asymmetric (8.4°/28.4°). While the symmetric grain boundary is observed to be straight with the symmetric (310)//(310) plane orientation, the asymmetric grain boundary is faceted into symmetric (310)//(310) and (210)//(210), and asymmetric (100)//(430). Grain-boundary impedance is observed only in the asymmetric grain boundary, and the electron energy-loss spectrometry quantification indicates that the asymmetric (100)//(430) facets are more oxygen-deficient than the symmetric ones. The results suggest that the asymmetric (100)//(430) facets are the most resistive among the three different facets. [Copyright &y& Elsevier]

Abstract: The pervasive deployment of P2P (peer-to-peer) systems and the multimedia contents overload in web environment raise a serious complexity for the peers where peers that participate in a P2P network are no longer able to effectively choose the contents they want. Recommender systems have been popularly used for reducing information overload of internet surfers by suggesting products or digital contents that are most valuable for them. But most existing recommender systems have been worked in client–server architecture. This paper proposes a PEOR (PEer-ORiented Recommender system), a collaborative filtering-based multimedia contents recommender system in P2P architecture, to obtain the peers’ search efficiency. To adopt a change in peer preferences PEOR uses recent ratings of peers for recommendations, thereby leading to better quality recommendations. And to enhance the system performance, PEOR searches for nearest peers with similar preference through peer-based local information only. We implemented the system and evaluated its performance with real transaction data in S content provider offering character images. Our experimental data shows that PEOR offers not only remarkably higher quality of recommendations but also the dramatically faster performance than the centralized benchmark system. [Copyright &y& Elsevier]

• Innovative Pavement Distress Detection: This study introduces a pioneering approach utilizing an RGB-D camera and instance segmentation algorithm to detect and quantify pavement distress, offering a unique solution to a critical infrastructure challenge. • Accurate 3D Point Cloud Analysis: The method efficiently converts pixel data into 3D point clouds, enabling precise assessment of distress area and severity, enhancing reliability in pavement condition evaluation. • Optimized Data Acquisition Strategy: Through rigorous testing and simulation using high-density polystyrene foam, the study identifies an optimal data acquisition scheme, ensuring dependable results even under varying experimental conditions. • Severity-Dependent Error Reduction: Findings demonstrate that error rates in area and volume measurements decrease as distress severity increases, highlighting the method's capacity to provide more accurate assessments for severe pavement issues. • Cost-effective Maintenance Solution: This approach offers a low-cost, high-precision solution for pavement distress detection and maintenance, presenting significant potential benefits for infrastructure management and maintenance planning. This study presents an innovative and cost-effective approach for pavement distress detection and quantification using an RGB-D camera in conjunction with an instance segmentation algorithm. The proposed method employs the instance segmentation algorithm to acquire 2D coordinate information pertaining to the affected pixels and integrates the internal reference matrix and depth data from the depth camera to transform the 2D images of the distressed areas into 3D point cloud data, consequently enabling distress quantification. To assess the dependability of the proposed approach, high-density polystyrene foam was used to simulate potholes and cracks of the pavement. Data collection was conducted under varying experimental conditions to identify the optimal data collection scheme. Using the approach, potholes and cracks of varying severity were collected from both asphalt and cement concrete pavements. The outcomes of the study demonstrate that the proposed methodology is capable of accurately detecting and quantifying potholes on the pavement. Furthermore, the errors associated with both the calculated area and volume exhibit a gradual decrease with an increase in the severity of pavement distress. However, for cracks, the method yields a larger error in results, primarily due to the instance segmentation algorithm's imprecise segmentation of crack edge pixels, despite superior restoration of the planar contour of cracks. [ABSTRACT FROM AUTHOR]

Abstract: Samaria-doped ceria (SDC) nanoparticles were prepared by spray pyrolysis. The means sizes of the samaria-doped ceria nanoparticles were controlled from 21 to 150nm by changing the calcination temperatures between 700 and 1200°C. The pellets formed from the SDC particles calcined at temperatures between 700 and 1000°C had similar grain sizes between 0.75 and 0.82μm. However, pellet formed from the SDC particles calcined at a temperature of 1200°C had large grain size of 1.22μm. The pellet formed from the SDC particles calcined at a temperature of 1000°C had slightly smaller resistance of grain-boundary than those of the pellets formed from the SDC particles calcined at temperatures between 700 and 900°C. However, the pellet formed from the SDC particles calcined at a temperature of 1200°C had low resistance of grain-boundary. The pellet formed from the SDC particles calcined at a temperature of 1200°C had conductivity of 44.65×10−3 Scm−1 at a measuring temperature of 700°C that more twice than those of the pellets formed from the SDC calcined below 1000°C. [Copyright &y& Elsevier]

Abstract: La0.8Sr0.2Ga0.8Mg0.2O3−δ (LSGM) electrolyte powders suitable for use in solid-oxide fuel cells were prepared by spray pyrolysis. The powders were spherical in shape and exhibited non-aggregation characteristics. The mean particle size of the LSGM powders was 0.89μm. The powders post-treated at temperatures of 1000 and 1300°C had main crystal structure of LSGM. The powders post-treated at temperatures of 1000 and 1300°C had impurity peaks of LaSrGa3O7 and LaSrGaO4 phases. Pellets sintered at 1300 and 1400°C had relative densities of 82% and 95% and mean grain sizes of 2.3 and 3.1μm, respectively. The pellet sintered at 1400°C had a lower value than that of the pellet sintered at 1300°C. The total conductivities of the pellets sintered at 1300 and 1400°C were 1.44×10−3 and 2.89×10−3 S/cm, respectively, at a low measuring temperature of 500°C. [Copyright &y& Elsevier]