Mechanical Properties of High-Performance Lightweight Aggregate Concrete with Inorganic Polymers Cement Based on Multiple Minerals under Uniaxial Loading

High-performance lightweight aggregate concrete with inorganic polymers cement based on multiple minerals is a very promising new material. The research of mechanical properties of the new material is of great theoretical and practical significance. In this research, the failure behavior, cubic and prism compressive strength, elastic modulus, peak strain of the new material, and the nature of the stress-strain curve are studied. An analytical model is quoted to represent the ascending and descending parts of the stress-strain curve

Influence of surface coating on structure and properties of metallic lithium anode for rechargeable Li-O2 battery

Abstract Amorphous lithium phosphorous oxynitride film was coated directly on pre-treated lithium metal as anode of lithium air battery by radio-frequency sputtering technique from a Li 3 PO 4 target. The structure and composition of modified anode was analyzed before and after charge/discharge test in a lithium-air battery, which comprises 0.5 M LiNO 3 /TEGDME as the electrolyte and super P carbon as cathode. Batteries were galvanostatically discharged by an Arbin BT-2000 battery tester between open current voltage and 2.15 V vs. Li + /Li at various current regimes ranging from 0.1–0.4 mA/cm 2 . Compared with fresh lithium, LIPON-coated anode exhibited better electrochemical performance. Good charging efficiency of 90% at a narrower voltage gap with high ionic conductivity of 9.4 × 10 −5 S/cm was achieved through optimizing lithium pre-treated conditions, sputtering N 2 flows and suitable solute for electrolyte

Crystallization of Poly (ethylene glycol) in Poly (methyl methacrylate) Networks

The crystallization of poly(ethylene glycol) (PEG) in poly(methyl methacrylate) (PMMA) networks were studied, which was compared with that of PEG homopolymer. Melting point (Tm) of PEG in PMMA networks is lower than that of pure PEG; the crystallinity and Tms of PEG in PMMA networks somewhat increase with increasing of PEG content; the cross-linker content of PMMA networks plays an important role for the crystallization of PEG. When the cross-linker content is between 3.5 wt% and 5.8 wt%, the distinct endothermic peak of PEG crystal fusion can be observed. Optical microscopic observation of the crystallized PEG in PMMA networks showed spherulite formation, indicating there was the co-continuous crystalline PEG in PMMA networks.DOI: http://dx.doi.org/10.5755/j01.ms.19.2.4430</p

Effects of prescribed burning on understory Quercus species of Pinus yunnanensis forest

IntroductionPositioning studies on prescribed burning in Pinus yunnanensis forests have been conducted for several years, focusing on the effects of fire on the composition and structure, growth, regeneration, relative bark thickness, and bark density of understory oak species in Pinus yunnanensis forests.MethodsThe study was conducted on Zhaobi Mountain, Yi-Dai Autonomous County of Xinping, Yuxi City, Yunnan Province. In the prescribed burn after restoration of full 1 year of the area and did not implement the prescribed burn area were set up 10 m × 10 m sample plots 30 pairs of comparisons, and all the oak trees in the sample plots were recorded, each sample plot in the four apexes and the middle were set up five 2 m × 2 m small sample squares, the shrubs in the small sample squares for each plant survey, comparison, statistics and analysis of all data.ResultsThe study results showed that (1) prescribed burning significantly affected the species composition of the understorey of Pinus yunnanensis forests. In both tree and shrub layers, the important values of Quercus aliena, Quercus serrata, Quercus fabri, and Quercus variabilis were significantly reduced in the burned areas. In contrast, the important values of Quercus acutissima increased somewhat. (2) The under crown height of oak trees in the burned areas was significantly lower than in the burned areas, but the height of oak trees in the burned areas was not significantly different from that in the burned areas. In the shrub layer, the height and cover of oak plants in the prescribed burning areas were significantly lower than in the unprescribed burned areas, effectively reducing the vertical continuity of the forest surface combustible material and reducing the possibility of fire converting from surface to canopy fire along the “ladder fuel.” (3) The regeneration of oak plants in the burned area is mainly by sprout tillers, and very few young sprouts are regenerated by seed germination. Renewed young sprouts are difficult to survive the prescribed burn areas the following year due to their lack of fire tolerance. (4) The relative bark thickness and density of oak plants in prescribed burn areas were significantly higher than those in unprescribed burn areas due to the fire tolerance exhibited by oak plants in long-term prescribed burns.DiscussionPrescribed burning has profoundly altered the structural composition and growth of oak plants in the understory of Pinus yunnanensis forests, and oak plants have shown significant fire-adapted traits to resist fire under long-term fire disturbance. The study can provide a scientific basis for prescribed burning, forest fuels, and forest fire management

A Systematic Investigation of the effect of wildfire events and risks on property values

Wildfires frequency and severity have been increasing in the western United States over the past few decades. This rising threat is caused by the accumulated fuel load, climate change, and the rapid expansion of housing in the wildland-urban interface (WUI). Since most mitigation and suppression costs are borne by taxpayers, policy analysts seek both market (e.g., protection and suppression cost) and non-market cost estimates of wildfires. As one tool, the hedonic pricing method is commonly used to investigate wildfire effects on property values. There are a variety of hedonic studies investigating wildfire, with mixed and/or inconsistent results. Model estimates are further complicated by a variety of data availability issues as well as varied econometric modeling decisions made by analysts. This analysis applies spatial econometrics modeling strategies in a hedonic pricing model framework to examine the joint effect of both past fire occurrence and current risk on property values in Santa Fe County, New Mexico. The objective of this analysis is twofold. First, I systematically investigate wildfire effects on property values via the hedonic model using a variety of modeling approaches, including varying or alternative measures for property values, wildfire event and risk, and econometric modeling techniques. Secondly, using hedonic results as primary estimates, I then investigate how the effect of wildfire varies with data availability and econometric modeling techniques through internal meta-analysis. The systematic investigation can be grouped and classified as measures for property values, wildfire occurrence and risk (which capture data availability issues), or econometric modeling techniques (which capture subjective modeling decisions of the analyst). The systematic investigation includes: two dependent variables (estimated sale price and assessed property value); two measures for wildfire events (the nearest fire measure and the aggregate fire measure with 4 buffer zones), each with two time frames (7 year and 15 year); three risk measures (GIS-based composite hazard and risk assessment, WUI risk assessment and individual-level house risk assessment); two commonly-used hedonic functional forms (semi-log and double-log); and four spatial dependency approaches (independent, spatial lag, spatial error, general spatial model), with three weight matrix. Overall, variations in data and econometric specification produce 2,000 regression results for hedonic model. Summarizing the direction of wildfire estimates, I find that past wildfire events/occurrences have a negative effect on property value. Specifically, the marginal implicit price (MIP) for a one kilometer increase in distance from the nearest fire $3,461 (in 2013 dollars), implying an increase in assessed value of 1.1$14,375 (in 2013 dollars), implying a decrease in assessed value of 4.6%. Secondly, the effects of risk on property value vary by risk measure, risk level, and geographic area. For composite risk and WUI risk, wildfire risk increases property values below a certain risk level and the relationship tends to be negative or insignificant once risk reaches that threshold; for house level risk it reduces property value. The effects of wildfire risk also differ across Non-WUI and WUI. In the Non-WUI area, the positive effects of amenity dominate, and thus wildfire risks tend to increase property value. However in the WUI the negative effects of wildfire risk offset, or even exceed the positive effects of amenities, resulting in a non-significant or negative relationship. Further, meta-analysis reveals the following results. First, models that use assessed value data give higher R2 than models that use estimated sales price data. The assessed value models also lead to more significant estimates and larger MIP estimates. Secondly, ignoring spatial autocorrelation either leads to overestimate of MIP or has no significant effect on MIP estimates. Third, the measurements of wildfire risk significantly influence effects of past wildfire events on property value. This reveals the importance of joint estimation of both wildfire events and wildfire risks. Ignoring the effects of wildfire risk in hedonic models might result in inappropriate estimates. Overall, this analysis systematically investigates the effect of past fire occurrence and current risk on housing prices, using a variety of data measures and modeling techniques. Different from previous studies, which only present “the best fit model”, this analysis conducts 2,000 hedonic regressions on wildfire effects, and then examines how judgements and choices made by researchers affect wildfire effects on property values. This approach synthesizes results of hedonic models in a concise and structured way, but also improves the robustness and reliability of our results in ways that are useful for informing policy recommendations

The Research Advances of Bioremediation Technology on the Petroleum Pollution Treatment

Petroleum pollution has become a well concerned environmental problem. Renovating and controlling the petroleum pollution is an important guarantee to recover the environmental function. In recent years, the effect of bioremediation technology in eliminating petroleum pollution has been concerned by people gradually, of which, the effect of microorganism is the most important part. The paper discusses the source of petroleum pollution, the hazard of petroleum pollution, bioremediation mechanism and bioremediation technology of petroleum pollution and prospects the development trend and application of microorganism in renovating water in the petroleum pollution

Investigating the Impact of Spatial Distribution of Sustainable Drainage System (SuDS) Components on Their Flood Mitigation Performance in Communities with High Groundwater Levels

This paper investigated the impact of the spatial distribution of SuDS components on their flood reduction performance and the underlying mechanisms in a community with high groundwater levels. The effects of SuDS components&rsquo; connectivity, decentralized level, and installation position along the flow direction on the reduction of total discharge volume (TDV), average discharge flow rate (ADFR), maximum discharge flow rate (MDFR), inundated area (IA), average inundated depth (AID), and maximum inundated depth (MID) were studied by coupling of the storm water management model (SWMM) and high-performance integrated hydrodynamic modelling system (HiPIMS). The results demonstrate that the connectivity has a positive linear correlation with the reduction of TDV (R2 &gt; 0.991), ADFR (R2 &gt; 0.992), and MDFR (R2 &gt; 0.958), while the decentralized level of rain gardens and green roofs present positive one-phase exponential correlation with the reduction of TDV (R2 &gt; 0.935), ADFR (R2 &gt; 0.934) and MDFR (R2 &gt; 0.967). A better-integrated mitigation of TDV and ADFR could be achieved by installing SuDS upstream along the flow direction. The connectivity from green roofs to rain gardens has a positive effect on the reduction of AID and MID but leads to the increase of IA. The findings of this study may contribute to the development of general spatial distribution guidelines and strategies to optimize the overall performance of SuDS components, especially at a community scale

Investigating the Impact of Spatial Distribution of Sustainable Drainage System (SuDS) Components on Their Flood Mitigation Performance in Communities with High Groundwater Levels

This paper investigated the impact of the spatial distribution of SuDS components on their flood reduction performance and the underlying mechanisms in a community with high groundwater levels. The effects of SuDS components’ connectivity, decentralized level, and installation position along the flow direction on the reduction of total discharge volume (TDV), average discharge flow rate (ADFR), maximum discharge flow rate (MDFR), inundated area (IA), average inundated depth (AID), and maximum inundated depth (MID) were studied by coupling of the storm water management model (SWMM) and high-performance integrated hydrodynamic modelling system (HiPIMS). The results demonstrate that the connectivity has a positive linear correlation with the reduction of TDV (R2 > 0.991), ADFR (R2 > 0.992), and MDFR (R2 > 0.958), while the decentralized level of rain gardens and green roofs present positive one-phase exponential correlation with the reduction of TDV (R2 > 0.935), ADFR (R2 > 0.934) and MDFR (R2 > 0.967). A better-integrated mitigation of TDV and ADFR could be achieved by installing SuDS upstream along the flow direction. The connectivity from green roofs to rain gardens has a positive effect on the reduction of AID and MID but leads to the increase of IA. The findings of this study may contribute to the development of general spatial distribution guidelines and strategies to optimize the overall performance of SuDS components, especially at a community scale

The Research Advances of Bioremediation Technology on the Petroleum Pollution Treatment

Petroleum pollution has become a well concerned environmental problem. Renovating and controlling the petroleum pollution is an important guarantee to recover the environmental function. In recent years, the effect of bioremediation technology in eliminating petroleum pollution has been concerned by people gradually, of which, the effect of microorganism is the most important part. The paper discusses the source of petroleum pollution, the hazard of petroleum pollution, bioremediation mechanism and bioremediation technology of petroleum pollution and prospects the development trend and application of microorganism in renovating water in the petroleum pollution