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To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2009.09.031 Byline: Jun Wang (a), Jia Li (a), Yingpeng Xie (a), Chengwu Li (a), Guangxi Han (a), Liquan Zhang (b), Rui Xu (a), Xiangdong Zhang (a) Abstract: In this work, Er.sup.3+:YAlO.sub.3/ZnO-TiO.sub.2 and ZnO-TiO.sub.2 composites were prepared by the ultrasonic dispersion and liquid boiling method. In succession, they were then characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Acid red B as a model dye compound was degraded under solar light irradiation to evaluate the photocatalytic activities of the Er.sup.3+:YAlO.sub.3/ZnO-TiO.sub.2 and ZnO-TiO.sub.2 composites. We found that the photocatalytic activity of ZnO-TiO.sub.2 composite can be enhanced by adding an appropriate amount of Er.sup.3+:YAlO.sub.3. We reviewed influencing factors, such as Er.sup.3+:YAlO.sub.3 content, heat-treated temperature and heat-treated time on the photocatalytic activity of the Er.sup.3+:YAlO.sub.3/ZnO-TiO.sub.2 composites. In addition, the effects of solar light irradiation time, dye initial concentration, Er.sup.3+:YAlO.sub.3/ZnO-TiO.sub.2 amount and solution acidity on the photocatalytic degradation of acid red B dye in aqueous solution were investigated in detail. Simultaneously, the degradation and comparison of other dyes such as methyl orange (MO), rhodamine B (RM-B), azo fuchsine (AF), congo red (CG-R) and methyl blue (MB) were also reviewed. In addition, we attempted to explore both the principle of possible excitation of Er.sup.3+:YAlO.sub.3/ZnO-TiO.sub.2 under solar light irradiation and the mechanism of photocatalytic degradation. Author Affiliation: (a) Department of Chemistry, Liaoning University, Shenyang 110036, PR China (b) Department of Pharmacy, Liaoning University, Shenyang 110036, PR China Article History: Received 1 March 2009; Revised 3 September 2009; Accepted 21 September 2009

• 1 Stress distribution was recalculated by stress-softening and prominent dilatancy. • 2 Gas-bearing coal under impact loading was a compaction followed by ruin process. • 3 Measures principles were mainly aimed at fracture and stress-concentration areas. • 4 Preliminary goal-reaching parameter based on principles was proposed and applied. As the increasing demand for coal and the depletion of shallow coal resources, the tendency of coal mining in China is progressively shifting to deeper areas, which brings about a circumstance where the frequency and intensity of coal and gas outburst accidents have further deteriorated. Nowadays, there are many outburst prevention measures being applied on site, while this disaster still occurs from time to time. Therefore, to better improve the preventing outcome of them, this paper came forward with some principles, based on the mechanical theory of deep mining and damage evolution procedure concerning coal containing gas underneath the impact load. The primary conclusions were as follows: the stresses, strains, and associated widths in the three areas, namely fracture area, plastic area, and elastic area, in front of the working face were recalculated by considering stress-softening and dilatancy of coal mass. The damage evolution of gas-bearing coal mass under impact loading was displayed in the LS-DYNA numerical simulation as a process of compaction followed by destruction. The proposed principles could be split into two perspectives, one for the fracture area, specifically, to minimize the descending of the coal mass's strength in this area; another for the stress-concentration zone, namely, to abate the thrust due to extrusion and deformation, on the coal body which was located in the front area. According to those principles, a preliminary goal-reaching parameter was proposed and it was implemented for the evaluation of advanced drilling. The results will cooperate to rationalize the design and layout of local outburst prevention measures, thereby enhancing the efficiency of control and ameliorating the deteriorating scenario of outburst disasters. [ABSTRACT FROM AUTHOR]

The physical condition and durability of cement-based structures can easily decrease after years of operation due to exposure to severe scenarios associated with internal defects, aggressive usage, and continuous load changes. Therefore, accurately assessing such infrastructures is essential for ensuring safety and serviceability and preventing hazards. In this study, an experimental investigation of the multimodal failure characteristics of cement mortar with various sand contents at different uniaxial compressive loading rates was conducted. Specifically, the multimodal failure characteristics include three main categories: mechanical properties (e.g., compressive strength), one-dimensional signals (e.g., micro-vibration and electromagnetic radiation), and two-dimensional videos/images (e.g., crack propagation trajectory). A geophysical acquisition and a high frame rate camera were employed to simultaneously record the micro-vibration, electromagnetic radiation and crack propagation videos of the cement specimens in a uniaxial compression test. Based on the computer vision technique and the feature pyramid network (FPN), an automatic pixel-level crack segmentation method was proposed to extract cracks of each critical moment in the fracture video. Then, the fractal dimension and crack area were calculated to quantitatively depict the crack propagation trajectory. Finally, the stress drop, micro-vibration, electromagnetic radiation, and crack propagation trajectory characteristics were analysed and discussed. The experimental results indicate the following. (1) The FPN offers a practical way to identify cracks in structures of cement-based materials at the pixel-level. (2) The micro-vibration, electromagnetic radiation, and crack propagation trajectory exhibit good consistency. In particular, the area and fractal dimension of cracks positively correlate with the stress drop of cement under compression loading. (3) The peak and cumulative energy values of micro-vibration and electromagnetic radiation tend to increase as the sand content increases when subjected to the same loading rate. • The multimodal failure characteristics of cement mortar are investigated. • A FPN-based crack segmentation model was proposed to extract cracks on cement. • Fractal dimension is employed to depict the crack propagation trajectory. [ABSTRACT FROM AUTHOR]

• The gas desorption process absorbs heat to reduce the temperature of the experimental system. • Coal sample particle size and adsorption equilibrium pressure have a significant effect on coal gas desorption. • As the coal sample particle size becomes smaller and the equilibrium pressure increases, the desorption amount and temperature changes increase, but the magnitude of the increase decreases. • The amount of desorption can be described linearly by the desorption temperature variation. Coal bed methane (CBM) is a clean energy source and its main component is methane, however, due to the complex conditions of its occurrence, its content detection is inaccurate and its utilization is not efficient. To further investigate the desorption and diffusion of methane in coal seams, this study uses an experimental system to investigate the desorption volume and temperature variations of gas desorption at different equilibrium pressures for three different particle sizes of coal samples. The results show that the desorption process is a heat absorption and cooling process, which is mainly influenced by the equilibrium pressure and the particle size of the coal samples. The amount of desorption and the absolute desorption temperature variation increases with increasing equilibrium pressure and increases with decreasing particle size of the coal sample. The desorption temperature variation at a desorption time of approximately 3000 s is close to the minimum. There is a linear relationship between the gas desorption volume and the absolute desorption temperature variation, which can be used to predict the desorption volume using the absolute desorption temperature variation. This will assist in the accurate measurement of coal bed methane content and the prevention and control of coal mine gas disasters. [ABSTRACT FROM AUTHOR]

Abstract: This study was performed to investigate the propagation law of microseismic signals transmitting along the direction parallel and vertical to the bedding in the process of coal rock rupture under uniaxial compression. Microseismic signals during the whole process of coal-rock deformation fracture until burst failure was tested by using the coal rock rupture microseismic experimental system. The empirical mode decomposition graphic, Hilbert spectrum and time–frequency spectrum were obtained by using Hilbert-Huang Transform or HHT. Also the microseismic signals transmitting along the direction parallel and vertical to the bedding in the process of coal rock rupture were spectrum comparative analyzed with EMD analysis method. Results show that amplitude and velocity of microseismic signals changed very small along the parallel direction to bedding in the process of propagation, but microseismic signals delayed and amplitude weakened obviously along the vertical direction to bedding. Signal delay and signal attenuation were confirmed that bedding impact on microseismic wave transmitting. [Copyright &y& Elsevier]

Abstract: The TiO2/Eggshell, TiO2/Clamshell and TiO2/CaCO3 loaded composites were prepared by sol–gel method and characterized by XRD and SEM. Their photocatalytic activities were measured through the degradation of Acid Red B under solar light irradiation. The influences of TiO2 loaded content, heat-treated temperature and time on the photocatalytic activities were reviewed. The effects of irradiation time and dye initial concentration on the photocatalytic degradation were also investigated. The results showed that the photocatalytic activity can be greatly enhanced by appropriate TiO2 loaded content. [Copyright &y& Elsevier]

Abstract: The TiO2/Skeleton, TiO2/Dens and TiO2/HAP composites were prepared by sol–gel method. X-ray diffraction (XRD) and scanning electron microscope (SEM) were carried out to characterize them. Their photocatalytic activities were evaluated by degradation of Acid Red B under solar light irradiation. The results showed that the photocatalytic activity of the TiO2 catalyst can be greatly enhanced by using appropriate amount of loaded biomaterials or biomimetic material. Otherwise, the influencing factors, such as TiO2 loaded content, heat-treated temperature and heat-treated time on the photocatalytic activity of TiO2/Skeleton, TiO2/Dens and TiO2/HAP were reviewed. Meanwhile, the effect of solar light irradiation time and dye initial concentration on the photocatalytic degradation of Acid Red B dye in aqueous solution were also investigated in detail. [Copyright &y& Elsevier]

The sorption capacity of coal is influenced by temperature, coal rank, mineral composition and moisture content. In the study, we experimentally measure the methane and carbon dioxide sorption capacity at various temperature for Illinois coal. A volumetric adsorption apparatus was employed to determine the excess gas adsorption capacity, and then the absolute adsorption capacity was estimated through the adsorbed gas phase density correction at each tested pressure. The adsorption isotherms were estimated for various temperatures from 283.15 K to 343.15 K. The experimental results indicated that both the methane and carbon dioxide adsorption capacities decrease linearly with an increase in temperature from 283.15 K up to 323.15 K, and the adsorption capacity reduction for CO 2 is more significant than that for methane. When the temperature is equal to or greater than 323.15 K, the adsorption capacities are independent of the temperature and remain constant for both gases. This means that there is a “ critical temperature point ” at which the influence of the temperature on the adsorption capacity vanishes, and the adsorption isotherms are very similar when the temperature is beyond the critical temperature point. The ratios of the CO 2 /CH 4 absolute adsorption capacities vary from 2.62 and 3.80 with the tested pressures and temperatures. [ABSTRACT FROM AUTHOR]

Abstract: The relativity between economic development and occupational accidents is a debated topic. Compared with the development courses of both economic development and occupational accidents in China during 1953–2008, this paper used statistic methods such as Granger causality test, cointegration test and impulse response function based on the vector autoregression model to investigate the relativity between economic development and occupational accidents in China from 1953 to 2008. Owing to fluctuation and growth scale characteristics of economic development, two dimensions including economic cycle and economic scale were divided. Results showed that there was no relationship between occupational accidents and economic scale during 1953–1978. Fatality rate per 105 workers was a conductive variable to gross domestic product per capita during 1979–2008. And economic cycle was an indicator to occupational accidents during 1979–2008. Variation of economic speed had important influence on occupational accidents in short term. Thus it is necessary to adjust Chinese occupational safety policy according to tempo variation of economic growth. [ABSTRACT FROM AUTHOR]

As it is hard to estimate the energy consumption and to optimize the cutting parameters in different tool wear status, this paper presents a novel intelligent reasoning system for the milling process. The system consists of three parts including the improved case based reasoning (ICBR), the adaptive neural fuzzy inference system (ANFIS) and the vibration particle swarm optimization (VPSO) algorithm. The ICBR is used for providing accurate estimation of cutting power. The inputs of ICBR are cutting parameters and tool wear status, and the output is cutting power. In ICBR, the similar cases to the inputs are retrieved using K-nearest neighbor and artificial neural network (ANN) methods in the case retrieval stage. In the case reuse stage, the Gaussian fuzzy grey correlation model is proposed to estimate the cutting power based on the retrieved similar cases. The VPSO algorithm is proposed to establish ANN and ANFIS models. With the aid of ANFIS-VPSO method, the optimal cutting parameters can be obtained under different machining conditions. The experimental results have confirmed that the VPSO algorithm has better global optimization ability than PSO and DE algorithms. The cutting speed has the greatest influence on the cutting power and cutting vibration. The estimation accuracy of ICBR is up to 91.7%, which are better than that of standard CBR and other intelligent models. The optimal cutting parameters are verified with an optimization error less than 13.5% by experiment results. The intelligent reasoning system can reduce energy consumption, maintain machine tool stability and improve machining efficiency. As an important platform, this system can realize clean and intelligent production. • Vibration PSO algorithm is proved to have great global optimization ability. • The trained ANN model indicates the cutting speed is the major impact factor. • ICBR is applied to estimate the energy consumption in complex machining process. • The proposed ICBR has the overall optimal estimation performance. • Optimal cutting parameters can be obtained by using ANFIS-VPSO method. [ABSTRACT FROM AUTHOR]

Highlights • The relationship of dynamic mechnical properties and crack propagation process of rock under SHPB loading has been explored. • A new calculation method of crack propagation velocity was proposed and crack propagation features were analyzed. • Based on Peridynamic thoery, a numerical model for rock material with BD configuration under SHPB test was proposed. Abstract To explore the dynamic mechanical properties and crack propagation law of rock under high strain rate impact loading, an experimental investigation with 12 sets of Brazilian disk (BD) rock specimens under Split Hopkinson Pressure Bar (SHPB) loading was undertaken. Unlike the previous researches that study the dynamic mechanical properties and crack propagation law individually, the relationship of them has also been investigated and discussed. More specifically, a dynamic resistance strain gauge and a high-frame camera were employed to simultaneously record stress wave data and rock destruction process videos under different impact velocities. Based on image processing technique, a new calculation method of crack propagation velocity was proposed and then the stress-strain characteristics and crack propagation features were analyzed. The experimental results indicate that: (1) Crack propagation rate of the crack along X-Y direction both rises with the impact velocity increase; (2) the strain of rock along the loading axis is much larger than the vertical direction; (3) there is a certain quantitative relationship between the stress-strain state and the crack area of the rock specimen after it has been damaged. Finally, a numerical model based on Peridynamic theory was developed to simulate crack propagation and dynamic constitutive relationship of rock materials with BD configuration in indirect tension test under SHPB loading, and further reveal the fracture behavior and mechanism of rock materials under high strain rate loading. [ABSTRACT FROM AUTHOR]

Civil infrastructure (e.g., buildings, roads, underground tunnels) could lose its expected physical and functional conditions after years of operation. Timely and accurate inspection and assessment of such infrastructures are essential to ensure safety and serviceability, e.g., by preventing unsafe working conditions and hazards. Cracks, which are one of the most common distress, can indicate severe structural integrity issues that threaten the safety of the structure and people in the environment. As such, accurate, fast, and automatic detection of cracks on structure surfaces is a major issue for a variety of civil engineering applications. Due to advances in hardware data acquisition systems, significant progress has been made in the automatic detection and quantification of cracks in recent decades. This paper provides a comprehensive review of the research progress and prospects in computer vision frameworks for crack detection of civil infrastructures from multiple materials, including asphalt, concrete, and metal-like materials. The review encompasses major components of typical frameworks, i.e., data acquisition techniques, publicly available datasets, detection algorithms, and evaluation metrics. In particular, we provide a taxonomy of detection algorithms with a detailed discussion of the advantages, limitations, and application scenarios of the methods in each category, as well as the relationships between methods of different categories. We also discuss unsolved issues and key challenges in crack detection that could drive future research directions. [ABSTRACT FROM AUTHOR]

The influences of dry grinding (DG), wet grinding (WG) and carbon nanofluid minimum quantity lubrication (CN-MQL) on the grinding performances of ceramic matrix composites are investigated in this paper. Thermal imager and thermocouple results show that the cooling effect of CN-MQL with a carbon concentration (C) of 5 g/L is not weaker than that of WG. The maximum temperature of 5 g/L CN-MQL is 250.41 °C, compared to 336.98 °C for DG. This configuration also results in the minimum surface roughness and grinding force. Normal grinding force F n and surface maximum height difference S z decrease from 44.9 N to 8.44 μm for DG to 20.3 N and 4.13 μm, respectively. The corresponding grinding performance is also substantially better than that of WG. The grinding surface morphology shows that CN-MQL is conducive to obtaining surface morphology with few surface defects. The specific grinding energy results show that the energy consumed by CN-MQL is significantly reduced when removing the same volume of material. Based on a comprehensive analysis of the grinding performance parameters, there is an optimal value of C. At lower values, a uniform and dense film cannot be formed between the abrasive tool and the workpiece. At higher values, the particles agglomerate, and the performance is reduced. The experimental results show that the optimal C is 5 g/L. Considering the high pollution and high cost of grinding fluids, CN-MQL technology has the advantages of a simple preparation process, green and pollution-free properties, and no professional disposal requirements. CN-MQL is also conducive to reducing energy consumption in the processing approach. This research shows that CN-MQL has good application prospects for grinding processes. [Display omitted] • Carbon nanoparticles MQL process improves eco-friendability of grinding process. • Effects of dry, wet and CN-MQL on the grinding performance were researched. • Influences of nanoparticles concentration of CN-MQL were studied. • CN-MQL with concentration of 5 g/L can achieve excellent grinding performance. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the molecular pathogenesis of Leber''s hereditary optic neuropathy (LHON) in Chinese families. Design: Six Han Chinese families who seem to have maternally transmitted LHON were studied by clinical, genetic, and molecular evaluations. Participants: One hundred twenty-seven subjects from 6 Chinese families with a wide range of age-at-onset and severity of visual impairment. Methods: All subjects underwent clinical examination, genetic evaluation, and molecular analysis of mitochondrial DNA (mtDNA). Main Outcome Measures: The ophthalmologic examinations included visual acuity, visual field examination, visual evoked potentials, and fundus photography. The mtDNA analysis included the polymerase chain reaction (PCR) amplification of entire mtDNA and subsequent sequence determination. Results: Six families exhibited low penetrance of visual impairment, with an average of 10.8%. In particular, 9 (6 males/3 females) of 86 matrilineal relatives in these families exhibited variable severity and age at onset in visual dysfunction. The average age at onset of visual loss was 20 years. Molecular analysis of mtDNA in these families identified the homoplasmic ND5 T12338C mutation and distinct set of variants belonging to the Asian haplogroup F2. The T12338C mutation is only present in the maternal lineage of those pedigrees and not in 178 Chinese controls. This mutation resulted in the replacement of the first amino acid, a translation-initiating methionine with a threonine, shortening 2 amino acids of ND5 polypeptide. The T12338C mutation is also located in 2 nucleotides adjacent to the 3′ end of the tRNALeu(CUN). Thus, this mutation may alter ND5 mRNA metabolism and the processing of RNA precursors. As a result, this mutation impairs respiratory function, leading to visual impairment. Conclusions: Several lines of evidence suggest that the mitochondrial ND5 T12338C mutation is associated with LHON. The tissue specificity of this mutation is likely due to the involvement of nuclear modifier genes. The identification of nuclear modifiers is important for the elucidation of the pathogenic mechanism of LHON and an open avenue for therapeutic interventions. The T12338C mutation should be added to the list of inherited risk factors for future molecular diagnosis. Our findings are helpful for counseling families with LHON. Financial Disclosure(s): The authors have no proprietary or commercial interest in any of the materials discussed in this article. [Copyright &y& Elsevier]

Since concrete infrastructure may lose its expected physical and functional properties over time, accurate inspection and assessment of such infrastructure systems is necessary to ensure safety and serviceability and prevent unsafe working conditions and the occurrence of hazards. In this paper, an experimental investigation was conducted on several concrete specimens under uniaxial compression to fully explore the fracture process and mechanical characteristics of concrete materials under compressive loading conditions. More specifically, a high-resolution industrial camera and a real-time geophysical acquisition system were employed to capture the fracture process and the microseismic (MS) and electromagnetic emission (EME) signals simultaneously. Based on digital image processing, a robust crack extraction algorithm was proposed for automatically identifying cracks on a concrete surface at the pixel level, and then two novel crack features were introduced to depict the dynamic crack propagation process quantitatively. Then, the correlation between MS, EME, stress drop and dynamic crack evolution characteristics was analyzed. The results indicate that: (1) the MS and EME signals of the concrete specimens have good consistency in the time domain, especially in the fully fractured stage; (2) the crack area, to a certain extent, can reflect the stress drop of a concrete specimen under the compression fracture process; (3) the crack propagation velocity parallel to the loading axis (along the vertical direction) is faster than that the perpendicular one to the loading axis (along the horizontal direction); and (4) the crack area, stress, MS signal, and EME signal reach their peak values nearly simultaneously. Finally, a novel mesh-free numerical model based on peridynamic (PD) theory was established to simulate the fracture process, and the displacement fields were presented to further reveal the failure mechanism of concrete under compressive loading. • A crack detection algorithm was proposed to identify cracks on the concrete surface. • Two crack morphological features were introduced to depict crack propagation. • The relationship of MS, EME, and crack propagation features has been investigated. • A Peridynamic model was built to simulate the fracture process of concrete. [ABSTRACT FROM AUTHOR]

• The dynamic test of coal specimens with different beddings was conducted using SHPB. • The crack propagation properties of coal were analyzed using fractal theory. • Peridynamic theory was used to simulate the dynamic fracture properties of coal. To investigate the crack propagation and dynamic mechanical properties of coal under high strain rate loading, 24 sets of Brazilian disk (BD) coal specimens with vertical and horizontal beddings were made, and tests were conducted by a split Hopkinson pressure bar (SHPB) system. Under different impact velocities, a high-frame and high-resolution camera was employed to capture the fracture process, and two high-dynamic strain gauges were used to record the stress pulse signals simultaneously. Using one-dimensional stress wave theory, the dynamic mechanical properties of coal with different bedding directions under different impact velocities were analyzed and discussed. Experimental results indicate that bedding directions not only have a major influence on dynamic mechanical properties such as dynamic tensile strength, strain rate and strain energy but also have a great influence on the crack propagation path. Then, based on the image processing technique and fractal method, cracks conforming to the fractal have been proven, and the results further illustrate that the fractal dimension of cracks on the coal surface increased in the fracture process under SHPB loading. Finally, a numerical model based on bond-based Peridynamic theory was proposed to simulate crack propagation and dynamic mechanical properties of coal under the SHPB test, and the displacement-strain-stress fields were also calculated, which further reveal the fracture mechanism and dynamic behavior of coal under different impact loading conditions. [ABSTRACT FROM AUTHOR]