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The phase pure large scale synthesis, second-harmonic generation, and piezoelectric properties of a vanadium phosphate, Li2VPO6 are reported. The material has been synthesized by a standard solid-state reaction using Li2CO3, V2O5, and NH4H2PO4 as reagents. The phase purity and crystal structure of the reported material have been confirmed by powder X-ray and neutron diffractions. The material crystallizes in orthorhombic space group Pna21 (no. 33) with a=10.32581(7)Å, b=4.63728(3)Å, c=8.56606(5)Å, and Z=4. The noncentrosymmetric layered structure is composed of distorted VO6 octahedra and PO4 tetrahedra. The V5+ cations distort either along the approximate [101] or [−101] directions attributable to the alignment of distorted VO6 octahedra, resulting in a polar structure. Powder second-harmonic generating (SHG) measurements on Li2VPO6 using 1064nm radiation, indicate the material has a SHG efficiency of approximately 10 times that of α-SiO2 and is not phase-matchable (type 1). Converse piezoelectric measurements for the material reveal a piezoelectric coefficient, d 33, of 12pmV−1. [ABSTRACT FROM AUTHOR]

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]

• 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]

For partial depth repair of airport concrete pavement, the thickness and physical properties of the materials used in the repair project are the prerequisite for the success of the repairing works. While under most actual constructions, these two factors are always regarded as the focus of the project, which leads to the re-damage of the repaired section once again. The repaired concrete pavement can be easily re-failed due to the incompatibility between the repair materials and the matrix concrete for their different characteristics in the aspect of thermal expansion and drying shrinkage. In general, the mechanistic model is used to calculate the interface stress by drying shrinkage and thermal expansion. However, the interface stiffness cannot be figured out by this way. In this study, the interface stress was calculated by the volume change of three kinds of repair materials which were Styrene Butadiene Rubber Concrete (SBR), Polymer Concrete (PC) and Coarse Aggregate Polymer Concrete (CPC). Besides, the characteristics of the interface behavior was also analyzed from the aspect of the interface slip and the shear stress. In the end, the calculation method for the interface stiffness was proposed. The procedure can be used in design. The slip range of these three sorts of repair materials is indicated by the test results of this study as follows, 900–1500 μm for SBR, 3000–9000 μm for PC and 6000–15,000 μm for CPC, and the interface stiffness of each material is 110.44 N/mm 3 , 45.65 N/mm 3 and 10.58 N/mm 3 respectively. [ABSTRACT FROM AUTHOR]

Few studies have been conducted on horizontal shifting prediction models that consider block shapes and laying patterns for block pavements. To develop a prediction model, a combination of different block shapes and laying patterns was evaluated by computer modeling and laboratory tests. The relationship between the force and displacement was recorded via a photogrammetric method using a friction tester. In order to quantify the recorded video results, rigid body analysis was performed. The results of laboratory experiments and the rigid body analysis offered a good match. A displacement vector was used to express the movement of the block with time, according to the start and end position information of each block. Also, a concept of Specific D-Moment (SDM) was proposed to describe the relationship between the movement of the individual blocks and the entire movement. A horizontal shifting mechanistic-empirical prediction model of concrete block pavement is proposed based on regression analysis of the existing performance data. According to the prediction model, higher SDM values give lower cumulative amounts of horizontal shifting due to traffic. [ABSTRACT FROM AUTHOR]

Pervious pavement has been used widely due to efficient hydrological characteristics such as reduction of runoff during floods, providing delay of rainwater into sewer systems and ground water quality improvement. However, clogging prevents it from functioning properly due to sedimentation after a short period of service, which results to poor permeability and performance of pervious pavement. In this study, the causes of clogging were investigated and a clogging simulator was developed in order to evaluate the sustainable permeability of porous concrete block pavement in advance. Furthermore, a test method for verifying the sustainability of infiltration which can predict and assess the permeability performance by years of service was proposed. In addition, the penetration of contaminants also varies depending on vehicle vibration and the rainwater that permeates together with it. It was found that the pores were easily clogged with the vibration frequency increased, but with the amount of contaminants increased to a degree clogging had less influence on vibration. When various types of porous concrete block pavers were evaluated with the proposed sustainable permeability test method, the coefficient of permeability before and after the test have shown very high correlation. [ABSTRACT FROM AUTHOR]

A new type of compliant polymer concrete for runway repair is introduced in this paper. To enhance the compliance of epoxy-based polymer concrete, some epoxy resin was replaced with liquid-type silicone rubber or tire waste powder. To estimate the temperature dependency of the mechanical behavior of the compliant polymer concretes, mechanical tests were also carried out. It was found that tire waste powder was more efficient than the silicone rubber in terms of mechanical performance. The experimental work revealed the 72:20:08(T) specimen provided the highest ductility factor while keeping the compressive strength above the minimum required value (30 MPa). [ABSTRACT FROM AUTHOR]

Phase pure Li2VPO6 is prepared by solid state reaction of a stoichiometric mixture of Li2CO3, V2O5, and NH4H2PO4 (Al2O3 crucible, 580 °C, 36 h, cooling rate 10 °C/h). [ABSTRACT FROM AUTHOR]

Abstract: Various preformed joint sealants (PJS) can be used for joint concrete pavement (JCP) to prevent the JCP from distresses such as pumping and faulting. Even though PJS have an important role in concrete pavement structures, most of the test methods that assess PJS focus on evaluating their basic mechanical and chemical properties rather than performance-related properties. In this study, a tester for PJS is developed and utilized to determine the resistant stiffness, which is considered to be a performance-related parameter, of PJS in transverse joints. The resistant stiffness is determined by dividing the peak force by the displacement; and the normalized value, which is used to simplify the relationship between the joint width and the sealant width, is determined by dividing the joint width by the sealant width. From laboratory tests performed on the developed tester, it is found that the resistant stiffness and normalized value are representative parameters that can be used to recommend the proper width of the joint, regardless of the joint width and joint type. Also, the relationship between the slip-down distress and the joint width, which is obtained from field survey results, can be utilized to recommend a minimum width for PJS. [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]

This study aimed to discriminate between the geographical origins of Asian red pepper powders distributed in Korea using Fourier-transform infrared (FT-IR) spectroscopy coupled with multivariate statistical analyses. Second-derivative spectral data were obtained from a total of 105 red pepper powder samples, 86 of which were used for statistical analysis, and the remaining 19 were used for blind testing. A one-way analysis of variance (ANOVA) test confirmed that eight peak variables exhibited significant origin-dependent differences, and the canonical discriminant functions derived from these variables were used to correctly classify all the red pepper powder samples based on their origins. The applicability of the canonical discriminant functions was examined by performing a blind test wherein the origins of 19 new red pepper powder samples were correctly classified. For simplicity, the four most significant variables were selected as discriminant indicator variables, and the applicable range for each indicator variable was set for each geographical origin. By applying the indicator variable ranges, the origins of the red pepper powders of all the statistical and blind samples were correctly identified. The study findings indicate the feasibility of using FT-IR spectroscopy in combination with multivariate analysis for identifying the geographical origins of red pepper powders.

Background: The type of payment is one of the important factors that has an effect on the health of employees, as a basic working condition. In the conventional research field of occupational safety and health, only the physical, chemical, biological, and ergonomic factors are treated as the main hazardous factors. Managerial factors and basic working conditions such as working hours and the type of payment are neglected. This paper aimed to investigate the association of the type of payment and the exposure to the various hazardous factors as an heuristic study., Methods: The third Korean Working Conditions Survey (KWCS) by the Occupational Safety and Health Research Institute in 2011 was used for this study. Among the total sample of 50,032 economically active persons, 34,788 employees were considered for analysis. This study examined the relation between the three types of payment such as basic fixed salary and wage, piece rate, and extra payment for bad and dangerous working conditions and exposure to hazardous factors like vibration, noise, temperature, chemical contact, and working at very high speeds. Multivariate regression analysis was used to measure the effect of the type of payment on working hours exposed to hazards., Results: The result showed that the proportion of employees with a basic fixed salary was 94.5%, the proportion with piece rates was 38.6%, and the proportion who received extra payment for hazardous working conditions was 11.7%., Conclusion: The piece rate was associated with exposure to working with tight deadlines and stressful jobs. This study had some limitations because KWCS was a cross-sectional survey.