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The advanced hydraulic support group combined with bolts (cables) constitutes the advanced coupling support system, which can ensure the stability of coal mine roadway safely and effectively. To explore the influence of the initial bearing capacity of the advanced hydraulic support on roadway roof deformation under anchor bar (cable) action. According to the actual geological conditions and roadway support of the 15106 working faces in Pingshuo Coal Mine, Yangquan, and Shanxi. Based on the change in the stress and displacement of the half‐space body under normal force in elastic theory and combined with the linear superposition principle, the contact mechanics model of the advanced hydraulic support group and roadway roof under anchorage is established. Selecting the measured anchor bar (cable) preload in the coal mine as the input load of the model, the stress and displacement distribution of the roadway roof under different initial bearing capacities are calculated. The calculation results show that the stress and displacement of the roadway roof along the axis exhibit a "symmetrical distribution" and the whole roadway exhibits a "saddle surface" gradient distribution during the active support of advanced hydraulic support under anchorage. The increase in the initial bearing capacity of the advanced hydraulic support has a great influence on the support effect in the middle area of the roadway and has a relatively small influence on the support effect in the surrounding area of the roof. With an increase in an initial support capacity, the stress gradient changes violently but substantially less than it would under the crushing strength of the surrounding rock. Using the similar simulation experiment theory, a similar simulation experiment roadway was established at 1:40, and the simulation experiment of an advanced hydraulic support coupling active support under anchor protection was carried out. The maximum error percentage of the theoretical calculation and experimental results of roof deformation under different initial bearing capacities is 19.51%, and the maximum error percentage of stress is 13.77%. The accuracy of the distribution law of roof stress and displacement under the initial bearing capacity in the process of active support obtained by theoretical calculation is verified. The research results provide a theoretical basis for advanced coupling adaptive support and the control of fully mechanized mining faces. [ABSTRACT FROM AUTHOR]

To understand the thermal evolution of lacustrine sedimentary n‐alkane hydrogen isotopic composition (δD), especially bacterially derived n‐alkanes, anhydrous thermal simulation experiments were performed with sediments from Lake Gahai (Gannan, China). We analyzed the original and pyrolysis‐generated n‐alkanes and their δD values. The results showed that thermal maturity and n‐alkane origins significantly affected the distribution of pyrolysis‐generated n‐alkanes. In immature to post‐mature sediments, the bacterial‐derived medium‐chain n‐alkanes generally had depleted δD values. The maximum difference in average δD values between the bacterial‐and herbaceous plant‐derived medium‐chain n‐alkanes was 32‰, and the maximum difference in δD values among individual n‐alkanes was 59‰. We found that the average δD value of pyrolysis‐generated n‐alkanes from different latitude was significantly different in immature to highly mature sediments, but similar in post‐mature ssediments. The hydrogen isotopes of sedimentary n‐alkanes can be used as indicators for paleoclimate/paleo‐environment conditions only when sediments are immature to highly mature. During thermal evolution, the δD value of generated individual n‐alkanes and the average δD value increased with thermal maturity, indicating that hydrogen isotopes of sedimentary n‐alkanes can be used as an index of organic matter maturity. We established mathematical models of average δD values of generated n‐alkanes from immature to post‐mature sediments using nC21−‐/nC21+ and average chain lengths. These results improve our understanding of the distribution and δD value of sedimentary n‐alkanes derived from herbaceous plants in mid‐latitude plateau cold regions. [ABSTRACT FROM AUTHOR]

Hydraulic fracturing experiments were conducted to study the change of initial fracture pressure and roof stress under repeated hydraulic fracturing in coal mines and to investigate the actual penetration enhancement effect on coal seams. The results show that as the fracturing is repeated, a lower initiation pressure is required. The roof stress changes consistently with water injection pressure. First, the stress in the area around the water injection hole gradually increases, and then stress transfers to the surroundings. With the re‐implementation of fracturing, the area of increased stress expands, and the scope of influence of hydraulic fracturing also becomes larger. When fracturing in a coal mine, for the same total fracturing time, the total water injection volume of repeated fracturing is 35% higher than that of single fracturing, and the affected area is increased by 31%. The concentration of repeated hydraulic fracturing is about 36% higher than that of a single hydraulic fracturing, and the pure flow of gas drainage is increased by about 1.3 times. The results of this study can guide the efficient implementation of hydraulic fracturing underground in coal mines, so as to achieve a larger impact range of coal seam hydraulic fracturing and better gas drainage effects. [ABSTRACT FROM AUTHOR]

Phthalate acid esters (PAEs) are one of the essential plastic additives which may lead to plenty of harmful effects, including reproductive toxicity, teratogenicity, and carcinogenicity. Increasing attention has been paid to the migration of plasticizer. In this article, the disposable plastic lunch boxes were taken as the research object. The result showed that dibutyl phthalate (DBP) and diisobutyl phthalate (DIBP) have been mainly found, whose content was 1.5 mg/kg and 2.4 mg/kg, respectively. The LOD was 2 ng/g, and LOQ was 6.7 ng/g. We further investigated the migration of PAEs into the simulated liquid at different temperature conditions. Then, the linear fitting performing by first‐order kinetic migration model revealed that the lower the polarity of the simulated liquid, the larger the rate constant K1 and initial release rate V0. The higher the temperature, the bigger the K1 and V0. [ABSTRACT FROM AUTHOR]

Micro-transmission lines are the physical model elements that own the same physical properties as the real transmission lines in power system, which are the significant components of a micro-dynamic simulation laboratory. This study presents an integrated experiment cabinet for micro-transmission lines (IECMTL). IECMTL integrates 20 micro-emulating transmission lines units, four micro-bus units and two light-synchronised phasor measurement units (PMU Lights). Benefitting from the same size and interface, researchers can change the position and wiring of any two transmission lines units according to the needs of the simulation experiment. PMU Lights are employed to get the operating status of micro-emulating transmission lines, including three-phase frequency, voltage phasor and current phasor. Appropriate software was developed on server to communicate with IECMTL in a two-way manner through the internet. Real-time monitoring and control features of IECMTL provide a flexible physical platform not only for innovative research ideas but also for education engineering of the power system. An example test-bed consisting of two IECMTLs was presented to simulate the power grids containing three generators and nine buses. [ABSTRACT FROM AUTHOR]

To understand the influence of the diagenetic water medium on the isotopic compositions of thermogenic coalbed gas, both hydrous and anhydrous closed‐system pyrolyses were performed at temperatures of 250°C to 650°C on an herbaceous marsh peat. Compared to the results of anhydrous pyrolysis, the hydrocarbon gases generated from hydrous pyrolyses have very different hydrogen isotopic compositions. However, the carbon isotopic compositions of the hydrocarbon gases became only slightly heavier in hydrous pyrolysis, compared to that from anhydrous pyrolysis. With the progress of thermal evolution from peat to a more advanced thermal maturity of vitrinite reflectance values (Ro) of 5.5% during the pyrolysis, the difference in the average δD value increased from 52‰ to 64‰ between the hydrous pyrolysis with saltwater and anhydrous pyrolysis and increased from 18‰ to 29‰ between the hydrous pyrolysis with freshwater and anhydrous pyrolysis, respectively. The difference in the average δ13C value was only 1‰–2‰ between the hydrous and anhydrous pyrolysis. The relationships between the δD values of the generated hydrocarbon gases and Ro values as well as among δD values of the hydrocarbon gas species are established. The close relationships among these parameters suggest that the water medium had a significant effect on the hydrogen isotopic composition and a minimal effect on the carbon isotopic composition of the hydrocarbon gases. The results of these pyrolyses may provide information for the understanding of the genesis of coalbed gas from herbaceous marsh material with the participation of different diagenetic water media. [ABSTRACT FROM AUTHOR]

An overview of uncertainty issues associated with the analytic hierarchy process (AHP) is provided. Further, an explicit understanding of uncertainty (designation, categorization, and quantification) with respect to the methodological properties of the AHP is developed and used to analyse a hypothetical group decision problem located in the context of environmental decision making (EDM). To calculate the numerical impact of especially designed uncertainty scenarios (USs) on the final ranking given by the AHP, a simulation experiment is conducted using R. It evaluates the impact of uncertainty within three variants of a hypothetical decision‐making case by calculating an "overall uncertainty" measure. The consideration of uncertainty may lead to a rank reversal in comparison with that analysis neglecting uncertainty (best alternative given by the AHP). The results show that the absolute maximal impact caused by a US is approximately 0.03. With respect to a single US and the specific case characteristics, in about 50% of the simulated runs a rank reversal occurs. Similar shares of rank reversal over different USs within a single variant of the case raise the question to which uncertainty should be given prior attention in decision‐making practice. For decision analysts in EDM, this result implies that additional resources may be necessary to commonly negotiate with decision makers that uncertainties should be addressed. From a theoretical normative point of view, the effects of considering uncertainty issues in the AHP methodology cannot satisfy the ideal of a rational decision analysis. From a descriptive point of view, considering the practice of decision makers, the impacts of the considered uncertainties stay within reasonable limits, meaning that the maximal numerical impact stays on the hundredths decimal place. [ABSTRACT FROM AUTHOR]

Abstract: In this study, the lithospheric strength of the Kaapvaal Craton is determined using deformation laws describing the failure of rocks at lithospheric depths. Shear wave velocity results from a previous study were used to constrain the rheological profiles associated with each of the 64 broadband seismic stations deployed across the craton. The other constraint, are the geotherms estimated assuming steady state conditions. In order to address the random and complex nature of uncertainties inherent in geotherms at lithospheric depths, a Monte Carlo simulation approach is used to find well‐constrained geotherms for each of the terrains within the craton. The optimized geotherms were subsequently used to determine the rheological profiles associated with each of the 64 localities. The resultant rheological profiles show seismogenic depths of 5–16 km for the craton and further show that the craton can basically be delineated into three strength domains. Most parts of the Kimberley terrain and minor parts elsewhere in the craton show a mechanically weak crust with a strength ratio less than 0.5, a substantial portion of the Witwatersrand terrain shows moderate strength ratios between 0.5 and 1.0, and the rest of the craton shows a mechanically strong crust corresponding to strength ratios greater than 1.0. Strength ratio is an indication of the extent of lower crustal to mantle strength. Low strength ratio regions correlate with parts of the craton that had a significant deformation history while high strength ratio regions correlate with a stable lithosphere that had minor or no deformation history. [ABSTRACT FROM AUTHOR]

Abstract: We refer to a theoretical trait space (TTS) as an n‐dimensional hypervolume (hypercube) characterizing the range of values and covariations among multiple functional traits, in the absence of explicit filtering mechanisms. We previously constructed a 32‐dimensional TTS for North American trees by fitting the Allometrically Constrained Growth and Carbon Allocation (ACGCA) model to USFS Forest Inventory and Analysis (FIA) data. Here, we sampled traits from this TTS, representing different individual “trees,” and subjected these trees to a series of gap dynamics simulations resulting in different annual light levels to explore the impact of environmental filtering (light stress) on the trait space. Variation in light limitation led to non‐random mortality and a refinement of the TTS. We investigated potential mechanisms underlying such filtering processes by exploring how traits and the environment relate to mortality rates at the tree, phenotype (a specific set of trait values), and stand (a specific gap scenario) levels. The average light level at the forest floor explained 42% of the stand‐level mortality, while phenotype‐ and tree‐level mortality were best explained by six functional traits, especially radiation‐use efficiency, maximum tree height, and xylem conducting area to sapwood area ratio (γX). These six “mortality” traits and six traits related to the leaf and wood economics spectra were used to construct trait hypercubes represented by trees that died or survived each gap scenario. For trees that survived, the volume of their refined trait space decreased linearly with increasing stand‐level mortality (up to ~50% mortality); the location also shifted, as indicated by non‐zero distances between the hypercube centroids of surviving trees compared to dead trees and the original TTS. Overall, the patterns were consistent with empirical studies of functional traits, in terms of which traits predict mortality and the direction of the relationships. This work, however, also identified potentially important functional traits that are not commonly measured in empirical studies, such as γX and senescence rates of relatively long‐lived tissues. [ABSTRACT FROM AUTHOR]

Susceptible host density is a key factor that influences the success of invading pathogens. However, for diseases affecting livestock, there are two aspects of host density: livestock and farm density, which are seldom considered independently. Traditional approaches of simulating disease outbreaks on real-world farm data make dissecting the relative importance of farm and livestock density difficult owing to their inherent correlation in many farming regions. We took steps to disentangle these densities and study their relative influences on epidemic size by simulating foot-and-mouth disease outbreaks on factorial combinations of cattle and farm populations in artificial county areas, resulting in 50 unique cattle/farm density combinations. In these simulations, increasing cattle density always resulted in larger epidemics, regardless of farm density. Alternatively, increasing farm density only led to larger epidemics in scenarios of high cattle density. We compared these results with simulations performed on real-world farm data from the United States, where we initiated outbreaks in U.S. counties that varied in county-level cattle density and farm density. We found a similar, but weaker relationship between cattle density and epidemic size in the U.S. simulations. We tested the sensitivity of these outcomes to variation in pathogen dispersal and farm-level susceptibility model parameters and found that although variation in these parameters quantitatively influenced the size of the epidemic, they did not qualitatively change the relative influence of cattle vs. farm density in factorial simulations. By reducing the correlation between farm and livestock density in factorial simulations, we were able to clearly demonstrate the increase in epidemic size that occurred as farm sizes grew larger (i.e., through increasing county-level cattle populations), across levels of farm density. These results suggest livestock production trends in many industrialized countries that concentrate livestock on fewer, but larger farms have the potential to facilitate larger livestock epidemics. [ABSTRACT FROM AUTHOR]

Question The empirical evidence of root herbivory effects on plant community composition and co-existence is contradictory. This originates from difficulties connected to below-ground research and confinement of experimental studies to a small range of environmental conditions. Here we suggest coupling experimental data with an individual-based model to overcome the limitations inherent in either approach. To demonstrate this, we investigated the consequences of root herbivory, as experimentally observed on individual plants, on plant competition and co-existence in a population and community context under different root herbivory intensities ( RHI), fluctuating and constant root herbivore activity and grazing along a resource gradient. Location Berlin, Germany, glasshouse; Potsdam, Germany, high performance cluster computer. Methods The well-established community model IBC-Grass was adapted to allow for a flexible species parameterization and to include annual species. Experimentally observed root herbivory effects on performance of eight common grassland plant species were incorporated into the model by altering plant growth rates. We then determined root herbivore effects on plant populations, competitive hierarchy and consequences for co-existence and community diversity. Results Root herbivory reduced individual biomass, but temporal fluctuation allowed for compensation of herbivore effects. Reducing resource availability strongly shifted competitive hierarchies, with, however, more similar hierarchies along the gradient under root herbivory, pointing to reduced ecological species differences. Consequently, negative effects on co-existence and diversity prevailed, with the exception of a few positive effects on co-existence of selected species pairs. Temporal fluctuation alleviated but did not remove negative root herbivore effects, despite of the stronger influence of intra- compared to interspecific competition. Grazing in general augmented co-existence. Most interestingly, grazing interacted with RHI and resource availability by promoting positive effects of root herbivory. Conclusions Through integrating experimental data on the scale of individual plants with a simulation model we verified that root herbivory could affect plant competition with consequences for species co-existence. Our approach demonstrates the benefit that accrues when empirical and modelling approaches are brought more closely together, and that gathering data on distinct processes and under specific conditions, combined with appropriate models, can be used to answer challenging research questions in a more general way. [ABSTRACT FROM AUTHOR]

The application of heat-treatment technology on lithic raw materials is an important feature of early modern human behaviour. The evidence of heat-treated stone artefacts discovered at Localities 2 and 12 of the Shuidonggou Late Palaeolithic site, North-West China, provides an important example for studying this technology among ancient humans in Asia during the Late Palaeolithic. The mechanism and effects of heat treatment on raw materials and the role of this technology in producing stone tools were studied by means of a simulation experiment and related analytical methods. These facilitated an in-depth analysis of the heat-treatment activities of the Shuidonggou occupants and their implications for cognitive ability and survival strategies of human populations at that time. [ABSTRACT FROM AUTHOR]

Stone knives were used widely in Neolithic East Asia, presumably in the harvesting of grain crops, but their function has not been clearly understood due to the lack of study of residues from these tools. To address this issue, starch grain analysis was employed to study the residues on the surface of ancient stone knives and large amounts of starches were recovered. The sources of these starches, however, were not well understood, because harvesting of crops involves the cutting of stems rather than direct contact with starchy seeds. To determine whether harvesting could deposit these types of residues, we designed a simulation experiment using stone flakes to harvest ears of wheat, rice and foxtail millet, then analysed the residues on both the flakes and in the plant tissues. A large number of starch grains were found in the stems, including both typical morphotypes from seeds and newly described types that occur only in stems, which can be used as indicators of harvesting. Our study demonstrates that starch grains from residues on the surfaces of archaeological stone knives can indicate not only that the tools were used to harvest ears, but also the type of crops harvested. [ABSTRACT FROM AUTHOR]

Pathogen invasions pose a growing threat to ecosystem stability and public health. Guidelines for the timing and spatial extent of control measures for pathogen invasions are currently limited, however. We conducted a field experiment using wheat (Triticum aestivum) stripe rust, caused by the wind-dispersed fungus Puccinia striiformis, to study the extent to which host heterogeneity in an initial outbreak focus influences subsequent disease spread. We varied the frequency of susceptible host plants in an initial outbreak focus and in the non-focus of experimental plots, and observed the progress of epidemics produced by artificial inoculation. The frequency of susceptible hosts in the initial outbreak focus increased the spread of stripe rust in the experimental plots, while frequency of susceptible hosts outside the initial outbreak focus did not. This suggests that factors influencing pathogen reproduction in the initial outbreak focus are key to the control of epidemics of stripe rust. Two mechanisms may underlie the field results. The first is the continuing, direct infection of susceptible hosts in areas outside the initial outbreak focus by disease propagules arriving from the initial outbreak focus. The second is highly local proliferation of disease caused by direct descendants of colonizing individuals originating from the initial outbreak focus. We considered these two alternatives in simulations of a generalized pathogen exhibiting fat-tailed dispersal, similar to P. striiformis. Simulations showed a dominant effect of conditions in the initial outbreak focus, in agreement with the field experiment, but indicated that, over time, this dominance may erode. Analysis of the duration of focal dominance led to the conclusion that both mechanisms contribute to the phenomenon of focal dominance, and that the frequency of susceptible hosts in the initial outbreak focus had a stronger influence when the proportion of propagules that remained local during dispersal was higher. Overall, our results suggest that targeting pathogen reproduction in the initial outbreak focus will have a disproportionately large impact on subsequent epidemic spread. [ABSTRACT FROM AUTHOR]

Thermochemical sulfate reduction (TSR) was conducted in autoclave on the system of crude oil and MgSO4 at different temperatures. Gas chromatography pulsed flame photometric detector (GC-PFPD) was used to detected the composition of organic sulfur compounds in oil phase products. The results of the analysis indicate that with increased temperature, the contents of organic sulfur compounds with high molecular weight and thermal stability, such as benzothiophenes and dibenzothiophenes, gradually became dominated. In order to gain greater insight into the formation and distribution of organic sulphur compounds from TSR, positive ion electrospray Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was used in detecting the detailed elemental composition and distribution of them. The mass spectra showed that the mass range of sulfur compounds was 200-550 Da. Four sulfur class species, S1, N1S1, O1S1 and O2S1, were assigned in the positive-ion spectrum. Among the identified sulfur compounds, the S1 class species was dominant. The most abundant S1 class species increase associated with the DBE value and carbon number increasing which also indicates the evolution of organic sulfur compounds in TSR is from the labile series to the stable one. In pure blank pyrolysis experiments with crude oil cracking without TSR, different composition and distribution of organic sulfur compounds in oil phase products were seen from mass spectra in order to evaluate their pyrolysis behaviors without MgSO4. FT-IR and XRD were used in analyzing the products of solid phases. Two distinct crystallographic phases MgO and MgSO4 are found to coexist in the products which demonstrated the transformation of inorganic sulfur compounds into organosulfur compounds exist in TSR. [ABSTRACT FROM AUTHOR]

1. Capture-recapture mixture models are important tools in evolution and ecology to estimate demographic parameters and abundance while accounting for individual heterogeneity. A key step is to select the correct number of mixture components i) to provide unbiased estimates that can be used as reliable proxies of fitness or ingredients in management strategies and ii) classify individuals into biologically meaningful classes. However, there is no consensus method in the statistical literature for selecting the number of components. 2. In ecology, most studies rely on the Akaike Information Criterion (AIC) and the Bayesian Information Criterion (BIC) that has recently gained attention in ecology. The Integrated Completed Likelihood criterion (ICL; IEEE Transactions on Pattern Analysis and Machine Intelligence, 2000, 22, 719) was specifically developed to favour well-separated components, but its use has never been investigated in ecology. 3. We compared the performance of AIC, BIC and ICL for selecting the number of components with regard to a) bias and accuracy of survival and detection estimates and b) success in selecting the true number of components using extensive simulations and data on wolf ( Canis lupus) that were used for management through survival and abundance estimation. 4. Bias in survival and detection estimates was <0.02 for both AIC and BIC, and more than 0.09 for ICL, while mean square error was <0.05 for all criteria. As expected, bias increased as heterogeneity increased. Success rates of AIC and BIC in selecting the 'true' number of components were better than ICL (68% for AIC, 58% for BIC, and 16% for ICL). As the degree of heterogeneity increased, AIC (and BIC in a lesser extent) overestimated the number of components, while ICL often underestimated this number. For the wolf study, the 2-class model was selected by BIC and ICL, while AIC could not decide between the 2- and 3-class models. 5. We recommend using AIC or BIC when the aim is to estimate parameters. Regarding classification, we suggest taking the classification quality into account by using ICL in conjunction with BIC, pending further work to adapt its penalty term for capture-recapture data. [ABSTRACT FROM AUTHOR]

The adsorption onto other minerals of charged gold nanoparticles, carried by gas ascending from the Earth’s interior, is an important component of their transport and deposition in surficial cover such as alluvial, aeolian, and glacial sediments. To simulate the adsorption of these particles, an experiment was conducted in which a flow of air that contained gold nanoparticles was passed upward through a sample of alluvium from the middle–lower reaches of the Yangtze River. These experiments showed that gold nanoparticles are adsorbed on kaolinite, halloysite, goethite, and hematite in the alluvial cover. Both the gold nanoparticles and minerals (i.e., kaolinite, halloysite, goethite, and hematite) carry surface charges that provide them with excellent adsorption properties. This study showed that the specific mineral composition of surficial alluvial cover affects the concentration of gold nanoparticles in the ascending gas. This phenomenon may plausibly be used in exploration for concealed gold, copper–gold, and silver–gold deposits in areas of thick alluvial cover. Geofluids (2010) 10, 438–446 [ABSTRACT FROM AUTHOR]

For effective use of mobile communication systems within a building, it is crucial to know the electromagnetic properties of the materials composing the floors, ceilings, walls, and so on. This paper considers RC (reinforced concrete) slabs, a major component of large buildings, and attempts to develop techniques for predicting and for measuring radio wave reflection and transmission characteristics in various environments. The frequency range considered in the analysis is approximately from 0.3 to 3.5 GHz, which is often used in mobile communications. As the first step, a slab with single-plane iron bar mesh buried in the concrete is assumed as the basic model for the analysis. A simulation experiment is performed with a 1/10 scale model, using microwaves or millimeter waves. A simulation calculation is also performed with a multiply stratified model, in which the iron mesh plane is replaced by an equivalent dielectric layer. The reflection and transmission characteristics are investigated as functions of the frequency and angle of incidence of the radio waves. The calculation results and measurements agree well, and the effectiveness of the method is verified. The characteristics of the basic analytical model are elucidated. A real floor consisting of metal mesh embedded in concrete is examined. The reflection characteristics for 2.0-GHz incident waves are examined by simulation calculation and by measurement with a network analyzer. The measurement technique is established and the dependence of the reflection characteristics on the incident polarization and angle of incidence is elucidated. © 2001 Scripta Technica, Electron Comm Jpn Pt 1, 85(1): 69–81, 2002 [ABSTRACT FROM AUTHOR]