83 research outputs found

    Comparison of Copper Leaching from Alkaline Copper Quat Type-D Treated Chinese Fir and Mongolian Scots Pine after Different Posttreatments

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    Chinese fir (Cunninghamia lanceolata Hook.) and Mongolian Scots pine (Pinus sylvestris Linn. var. mongolica Litv.) sapwood were treated with alkaline copper quat type D (ACQ-D) solutions at two concentration levels (0.5 and 1.1%) followed by three posttreatments: oven-drying, conditioning in a humidity chamber, or exposed to boiling water. The effects of treatment on copper leaching from ACQ-D-treated wood were investigated by performing tests according to AWPA E11-06. Analysis of chemical composition and pH values were determined to evaluate the effects of wood species on copper leaching. The results showed that copper leaching from ACQ-D-treated Mongolian Scots pine without posttreatment was lower than that of treated Chinese fir. However, after posttreatment, more copper leaching was observed from ACQ-D-treated Mongolian Scots pine than Chinese fir. For example, after conditioning posttreatment, the percentage of copper leached from 1.1% ACQ-D-treated Chinese fir decreased 58.6 to 1.8%, while for Mongolian Scots pine, it decreased 49.5 to 19.4%. The difference was considered to be related to different chemical compositions and pH levels

    No. 14: The Impact of Proximity to Wet Markets and Supermarkets on Household Dietary Diversity in Nanjing City, China

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    Existing studies suggest that despite the proliferation of supermarkets, traditional wet markets have persisted in many countries and have been playing an important role in people’s daily food access. Yet, studies investigating the issue of food access and its influences on food security have mainly focused on food deserts and the proximity to supermarkets, with limited focus on wet markets and other food outlets. This study investigates the influence of the proximity to wet markets and supermarkets on urban household dietary diversity in Nanjing. Based on the data collected through a citywide survey in 2015 and the map data of wet markets and supermarkets, the Poisson regression model was deployed to examine the correlations between geographical proximity to supermarkets and wet markets and household dietary diversity. The results show that the coefficients for the distance to the nearest wet market are not statistically significant. Although the coefficients for the distance to nearest supermarket are statistically significant, they were too minor to be of practical importance. We argue, however, that the insignificant correlations reflect exactly the high physical accessibility to food outlets and the extensive spatially dense food supply network constituted by wet markets, supermarkets and small food stores in Nanjing. This is verified by the survey data that more than 90% of households purchased fresh food items within their neighbourhoods or in walking distance. In addition to the densely distributed food outlets, various other factors contributed to the non-significant influence of the distance to the nearest wet market and supermarket, including the many small food stores within or close to residential communities, the prevalence of three-generation extended households and high household income. This study highlights the importance of allowing mixed land use for food outlets with residential land and integrating wet markets into urban infrastructure planning

    Stepwise Observation and Quantification and Mixed Matrix Membrane Separation of CO2 within a Hydroxy-Decorated Porous Host

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    The identification of preferred binding domains within a host structure provides important insights into the function of materials. State-of-the-art reports mostly focus on crystallographic studies of empty and single component guest-loaded host structures to determine the location of guests. However, measurements of material properties (e.g., adsorption and breakthrough of substrates) are usually performed for a wide range of pressure (guest coverage) and/or using multi-component gas mixtures. Here we report the development of a multifunctional gas dosing system for use in X-ray powder diffraction studies on Beamline I11 at Diamond Light Source. This facility is fully automated and enables in situ crystallographic studies of host structures under (i) unlimited target gas loadings and (ii) loading of multi-component gas mixtures. A proof-of-concept study was conducted on a hydroxyl-decorated porous material MFM-300(V-III) under (i) five different CO2 pressures covering the isotherm range and (ii) the loading of equimolar mixtures of CO2/N-2. The study has successfully captured the structural dynamics underpinning CO2 uptake as a function of surface coverage. Moreover, MFM-300(V-III) was incorporated in a mixed matrix membrane (MMM) with PIM-1 in order to evaluate the CO2/N-2 separation potential of this material. Gas permeation measurements on the MMM show a great improvement over the bare PIM-1 polymer for CO2/N-2 separation based on the ideal selectivity

    Hybrid Optimization Algorithm of Particle Swarm Optimization and Cuckoo Search for Preventive Maintenance Period Optimization

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    All equipment must be maintained during its lifetime to ensure normal operation. Maintenance is one of the critical roles in the success of manufacturing enterprises. This paper proposed a preventive maintenance period optimization model (PMPOM) to find an optimal preventive maintenance period. By making use of the advantages of particle swarm optimization (PSO) and cuckoo search (CS) algorithm, a hybrid optimization algorithm of PSO and CS is proposed to solve the PMPOM problem. The test functions show that the proposed algorithm exhibits more outstanding performance than particle swarm optimization and cuckoo search. Experiment results show that the proposed algorithm has advantages of strong optimization ability and fast convergence speed to solve the PMPOM problem

    The impact of different benefit packages of Medical Financial Assistance Scheme on health service utilization of poor population in Rural China

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    <p>Abstract</p> <p>Background</p> <p>Since 2003 and 2005, National Pilot Medical Financial Assistance Scheme (MFA) has been implemented in rural and urban areas of China to improve the poorest families' accessibility to health services. Local governments of the pilot areas formulated various benefit packages. Comparative evaluation research on the effect of different benefit packages is urgently needed to provide evidence for improving policy-making of MFA. This study was based on a MFA pilot project, which was one component of Health VIII Project conducted in rural China. This article aimed to compare difference in health services utilization of poor families between two benefit package project areas: H8 towns (package covering inpatient service, some designated preventive and curative health services but without out-patient service reimbursement in Health VIII Project,) and H8SP towns (package extending coverage of target population, covering out- patient services and reducing co-payment rate in Health VIII Supportive Project), and to find out major influencing factors on their services utilization.</p> <p>Methods</p> <p>A cross-sectional survey was conducted in 2004, which used stratified cluster sampling method to select poor families who have been enrolled in MFA scheme in rural areas of ChongQing. All family members of the enrolled households were interviewed. 748 and 1129 respondents from two kinds of project towns participated in the survey. Among them, 625 and 869 respondents were included (age≥15) in the analysis of this study. Two-level linear multilevel model and binomial regressions with a log link were used to assess influencing factors on different response variables measuring service utilization.</p> <p>Results</p> <p>In general, there was no statistical significance in physician visits and hospitalizations among all the respondents between the two kinds of benefit package towns. After adjusting for major confounding factors, poor families in H8SP towns had much higher frequency of MFA use (β = 1.17) and less use of hospitalization service (OR = 0.7 (H8SP/H8), 95%CI (0.5, 1.0)) among all the respondents. While calculating use of hospital services among those who needed, there was significant difference (p = 0.032) in percentage of hospitalization use between H8SP towns (46%) and H8 towns (33%). Meanwhile, the non-use but ought-to-use hospitalization ratio of H8SP (54%) was lower than that of H8 (67 %) towns. This indicated that hospitalization utilizations had improved in H8SP towns among those who needed. Awareness of MFA detailed benefit package and presence of physician diagnosed chronic disease had significant association with frequency of MFA use and hospitalizations. There was no significant difference in rate of borrowing money for illness treatment between the two project areas. Large amount of medical debt had strong association with hospitalization utilization.</p> <p>Conclusions</p> <p>The new extended benefit package implemented in pilot towns significantly increased the poor families' accessibility to MFA package in H8SP than that of H8 towns, which reduced poor families' demand of hospitalization services for their chronic diseases, and improved the poor population's utilization of out-patient services to some degree. It can encourage poor people to use more outpatient services thus reduce their hospitalization need. Presence of chronic disease and hospitalization had strong association with the presence of large amount of medical debt, which indicated that: although establishment of MFA had facilitated accessibility of poor families to this new system, and improved service utilization of poor families to some degree, but its role in reducing poor families' medical debt resulted from chronic disease and hospitalization was still very limited. Besides, the following requirements of MFA: co-payment for in-patient services, ceiling and deductibles for reimbursement, limitations on eligibility for diseases reimbursement, also served as most important obstacles for poor families' access to health care.</p> <p>Therefore, there is great need to improve MFA benefit package design in the future, including extending to cover out-patient services, raising ceiling for reimbursement, removing deductibles of MFA, reducing co-payment rate, and integrating MFA with New Rural Cooperative Medical Scheme more closely so as to provide more protection to the poor families.</p

    Polissage et adhérence des chaussées routières

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    The thesis deals with road skid resistance, and with the possibility to predict its evolution through laboratory tests and models. First an original laboratory method is presented to polish and to measure the friction coefficient, using the Wehner & Schulze machine, developed in Germany. This method allows the measurement of friction coefficient vs. polishing time. Road sites are monitored to compare laboratory results with actual skid resistance. In parallel with experiments, mathematical models are built. A 5-parameter best fit model is first proposed, some parameters of which are related with aggregate characteristics, such as PSV, maximum size and microtexture. Then, a more physical model is described, which separates the three main mechanisms (ageing and wear of bitumen, polishing of aggregate particles). An equivalence coefficient is established between heavy lorry traffic and the number of wear cycles in laboratory. Such a model should allow in the future the rational choice of surface material, and the prediction of skid resistance of a new pavement wearing course. Finally, the surface profiles are examined at various polishing states, in order to link skid resistance with roughness parameters and aggregate properties (PSV, MDE, LA).La présente thèse concerne l'adhérence des pneumatiques avec les chaussées routières, et la possibilité de prévoir son évolution à l'aide d'essais de laboratoire et de modélisations. Tout d'abord, une méthodologie originale de polissage et de mesure de l'adhérence en laboratoire est présentée ; elle s'appuie sur la machine de Wehner et Schulze, développée en Allemagne. Grâce à elle, on peut mesurer l'évolution du coefficient de frottement avec la durée du polissage. Des chantiers routiers sont suivis dans le temps, afin de comparer la simulation en laboratoire et l'évolution réelle de l'adhérence. Parallèlement à la simulation expérimentale, des lois d'évolution sont établies. Un modèle à cinq paramètres est tout d'abord proposé, que l'on tente de relier aux caractéristiques des granulats (PSV, diamètre maximal, microtexture, etc.). Ensuite, un modèle plus physique est ébauché, explicitant les mécanismes de vieillissement et de décapage du bitume, et de polissage des granulats. Un coefficient d'équivalence entre le trafic poids lourd et le nombre de cycles d'usure en laboratoire est proposé, devant permettre à terme de choisir entre différents matériaux de couche de surface, et de prévoir l'évolution de l'adhérence d'une chaussée neuve. Enfin, les profils de surface sont examinés à différents états de polissage, dans le but de relier l'évolution de l'adhérence aux paramètres de rugosité, et aux caractéristiques des granulats (PSV, MDE, LA)

    Effects of Hot Water Posttreatment on Accelerating Copper Fixation in ACQ-D-Treated Chinese FIR

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    The effects of hot water posttreatments on accelerating copper fixation in alkaline copper quat-type D (ACQ-D) -treated Chinese fir [C. lanceolata (Lamb.) Hook] were evaluated. The rate and extent of copper fixation in treated wood posttreated at 60, 80, and 100°C were monitored by analyzing the copper content in the expressed solution over time. The fixation qualities of copper in treated wood after different hot water posttreatments were evaluated by the AWPA E11-06 leaching test. The valence conversion of copper in treated wood was investigated by UV/visible spectroscopy. The expressing results showed that copper stabilized much faster during hot water posttreatments, especially at 80 and 100°C; more than 90% of copper could be fixed in treated wood in less than 2 h. The valence conversion of copper was highly dependent on the temperature and duration of the treatment. After a 100°C hot water bath of 6 h, more than 40% of cupric copper was reduced to cuprous forms. Based on the results of leaching tests of ACQ-D-treated wood, the best copper leaching resistance was obtained at 100°C; the percentage of copper leaching was reduced to about 12% when posttreated for 9 h. The compressive strength of treated wood was not impaired significantly in that condition

    Large deformation measurement scheme for 3D digital image correlation method

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    Difficulties often arise for digital image correlation (DIC) technique when serious de-correlation occurs between the reference image and the deformed image due to large deformation. An updating reference image scheme could be employed to deal with large deformation situation, however that will introduce accumulated errors. A large deformation measurement scheme, combining improved coarse search method and updating reference image scheme, is proposed in this paper. For a series of deformation images, the correlation calculation begins with a seed point and spreads out. An improved coarse search method is developed to calculate the initial correlation parameters for the seed point, which guarantees that the correlation calculation can be carried out successfully even in large deformation situation. Only for extremely large deformation, the reference image is updated. Using this method, not only extremely large deformation can be measured successfully but also the accumulated error could be controlled. A polymer material tensile test and a foam compression test are used to verify the proposed scheme. Experimental results show that up to 450% tensile deformation and 83% compression deformation can be measured successfully

    Multilayered Pipe Cutting Test for Remote Handling Maintenance

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    Based on the requirements for remote handling maintenance (RHM) of China Spallation Neutron Source (CSNS) multilayered pipes, pipes cutting tests were performed under remote handling maintenance conditions. In this study, the results were obtained from different cutting directions and supporting intensities of pipe baseplates comparisons: When enough power was provided and the blade gripper did not slip, the cutting direction had little impact on the cutting capacity but more on the fault surface; the clearance between the blades caused the rotating torque; for remote handling maintenance, good horizontal support of the long-handled lever of the hydraulic cutter was required. Significant conclusions were made for multilayered pipe cutting that are crucial for auxiliary tools development for remote handling maintenance
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