Mine Experimental Research of the Power Options of Mechanized Fastening Sections Based on Lithological Structure Coefficient

The results of simulation systems of the rock-mass using the new mathematical approaches and modern information software are introduced. The contacts of rock mass strata are presented as the curves in the simulation model. In such way, it is forming the specific zones with different strengthening characteristics. Authors propose to define the deformations of roof rocks and loadings on mechanized complex according to the values of the lithological structure coefficient. This parameter also is used for the correcting the technological parameters of the mining in wallfaces

In situ aerosol measurements taken during the 2007 COPS field campaign at the Hornisgrinde ground site

Copyright @ 2011 Royal Meteorological Society.The Convective and Orographically-induced Precipitation Study (COPS) campaign was conducted during the summer of 2007. A suite of instruments housed at the top of the Hornisgrinde Mountain (1156 m) in the Black Forest region of south-west Germany provided datasets that allow an investigation into the physical, chemical and hygroscopic properties of the aerosol particles sampled during COPS. Organic mass loadings were found to dominate the aerosol composition for the majority of the project, exceeding 8 µg m−3 during a period of high pressure, high temperature, and low wind speed. The ratio of organic:sulphate sub-micron mass concentration exceeds 10:1 during the same time period. Back trajectories show air from this time-frame passing slowly over the local forest and not passing over any local anthropogenic sources. Occasional peaks in nitrate mass loadings were associated with changes in the typical wind direction from south-westerly to north-westerly where air had passed over the Stuttgart region. Size distribution data shows a dominant accumulation-mode when the measurement site was free from precipitation events. A sharp increase in ultrafine particle number concentration was seen during most days commencing around noon. The apparent growth of these particles is associated with an increase in organic mass loading, suggesting condensational growth. For the most part, with the exception of the high pressure period, the aerosol properties recorded during COPS were comparable to previous studies of continental aerosol properties.NER

Posterior contraction in sparse Bayesian factor models for massive covariance matrices

Sparse Bayesian factor models are routinely implemented for parsimonious dependence modeling and dimensionality reduction in high-dimensional applications. We provide theoretical understanding of such Bayesian procedures in terms of posterior convergence rates in inferring high-dimensional covariance matrices where the dimension can be larger than the sample size. Under relevant sparsity assumptions on the true covariance matrix, we show that commonly-used point mass mixture priors on the factor loadings lead to consistent estimation in the operator norm even when $p\gg n$. One of our major contributions is to develop a new class of continuous shrinkage priors and provide insights into their concentration around sparse vectors. Using such priors for the factor loadings, we obtain similar rate of convergence as obtained with point mass mixture priors. To obtain the convergence rates, we construct test functions to separate points in the space of high-dimensional covariance matrices using insights from random matrix theory; the tools developed may be of independent interest. We also derive minimax rates and show that the Bayesian posterior rates of convergence coincide with the minimax rates upto a $\sqrt{\log n}$ term.Comment: Published in at http://dx.doi.org/10.1214/14-AOS1215 the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org

Mass Loadings of Selected Water Quality Parameters for the State of Florida

The mass loadings of pollutants common in surface waters result from the discharges of many different sources. In the last few years it has been noted that nonpoint sources contribute more pollutants than point sources. This is because in many cases the point source discharges have been, by law, reduced drastically. In the State of Florida many water quality parameters were examined to estimate the mass loadings in streams related to, drainage area, average flow, land use, soil type and management practices. A total of sixteen streams were examined. The information was first calculated for mass loadings as a function of stream flow. Next the slopes and intercepts were related to drainage area. Both steps were accomplished using bi-variate regression analysis. The final results show a relationship of Total Organic Carbon, Orthophosphate, Total Phosphate and Nitrate to drainage area and stream flow. However, the final results of this study when related to another study in Florida showed different mass loading rates for TOC and TP. The differences were attributed to background levels of pollutants, local geology, hydrologic variability and management practices

Oxygen reduction in acid media: effect of iron substitution by cobalt on heat-treated naphthalocyanine impregnations supported on preselected carbon blacks

FeNPc(1.2) impregnations were investigated at various loadings using a rotating-disk electrode, voltammetry and X-ray photoelectron spectroscopy (XPS) techniques. Optimal activity takes place at monolayer coverage, and major demetallation occurs after prolonged exposure to acid solution. The substitution of Fe by Co enables the electrochemical performances to reach those presented by 10% Pt on Vulcan and stops the demetallation process. The application of fast atomic bombardment secondary ion mass spectrometry (FABS) together with XPS sheds light on the detrimental role of some electrophilic groups attached to the carbon black-catalyst interface

The International Mass Loading Service

The International Mass Loading Service computes four loadings: a) atmospheric pressure loading; b) land water storage loading; c) oceanic tidal loading; and d) non-tidal oceanic loading. The service provides to users the mass loading time series in three forms: 1) pre-computed time series for a list of 849 space geodesy stations; 2) pre-computed time series on the global 1deg x 1deg grid; and 3) on-demand Internet service for a list of stations and a time range specified by the user. The loading displacements are provided for the time period from 1979.01.01 through present, updated on an hourly basis, and have latencies 8-20 hours.Comment: 8 pages, 3 figures, to appear in the Proceedings of the Reference Frames for Applications in Geosciences Simposium, held in Luxemboug in October 201

Mass mortalities in bivalve populations: A review of the edible cockle Cerastoderma edule (L.)

Mass mortalities in bivalve populations have long been of particular concern, especially when the species supports a commercial fishery or is of conservation interest. Here we consider the evidence of mass mortalities of the edible cockle, Cerastoderma edule (L.). Through the construction of a conceptual model eight potential factors (or groups of factors) which may cause mass mortalities are identified and reviewed. These include: food limitation; density; oxygen depletion and organic loadings; temperature and salinity; parasites, pathogens and commensals; toxicants and other persistent pollutants; predation, and changes in sediment, suspended solids, topography and bathymetry. The interplay between factors in recognized and discussed based on evidence mainly from the published literature relating to temperate edible cockle beds. Anecdotal evidence is also reported from a structured survey of site-specific evidence provided by fisheries managers in England and Wales. Case studies from the UK and Europe indicate that there is often no single, clear generic cause of mass mortalities in cockle populations. The importance of linked site-specific scientific investigations and laboratory-based experiments to fill the gaps in our current understanding of mass mortalities in bivalve species is highlighted as necessary to take account of both local extrinsic and intrinsic factors

Effect of Carbon Black Electrocatalyst Thickness and Composition on Electrosynthesis of Hydrogen Peroxide on Gas Diffusion Electrodes

The in-situ electrosynthesis of hydrogen peroxide (H2O2) from reduction of oxygen is a promising method to produce a strong oxidant and disinfectant for application in the water and wastewater treatment industry. Capable of producing low concentrations of H2O2 with no aeration requirements and harmless by-products of water and oxygen, the electrosynthesis of H2O2 using gas diffusion electrodes is advantageous. This research examines the impact that electrocatalyst thickness and composition have on the production efficiency of H2O2 at the gas diffusion layer of a gas diffusion electrode. From these results, the optimum electrocatalyst loading and composition with its respective energy requirements is assessed. An increase in electrocatalyst loading on the gas diffusion layer saw a greater thickness of the electrocatalyst layer, increasing the perpendicular diffusion pathway required for H2O2 to reach the electrolyte solution. At a current density of 1 mA/cm2, the lowest electrocatalyst loading of 0.5 mg/cm2 produced the highest H2O2 concentration of 807.54 mg/L and maximum current coulombic efficiency of 53%. The H2O2 produced from the additional three electrocatalyst loadings of 1.5, 3.0, and 5.0 mg/cm2 decreased linearly with increasing loading. An increase in the length of the diffusion pathway allows more time for H2O2 to accumulate and degrade to H2O or O2. As current density was increased, higher yields of H2O2 were achieved for all loadings, suggesting less chemical degradation of H2O2 to O2 as the higher electrocatalyst loadings significantly improved current efficiencies to match the lower electrocatalyst loadings. An energy input analysis calculating the mass produced/energy input in kg H2O2/kWh demonstrated a benefit in selecting higher electrocatalyst loadings at higher current densities. Although the highest electrocatalyst loading of 5.0 mg/cm2 produced the lowest concentrations of H2O2 at a current density of 5 mA/cm2, it accomplishes the greatest mass produced/energy input of 3.84 kg H2O2/kWh. The effect of electrocatalyst composition was examined as electrocatalyst loadings of 1.5 and 5.0 mg/cm2 were tested with and without proton exchange polymer, Nafion, in the electrocatalyst carbon ink. The electrocatalyst loadings comprised of a carbon ink without Nafion resulted in greater H2O2 concentrations and current efficiencies, with smaller differences between loadings compared to the results for loadings containing Nafion. At the cathode surface, pH increases rapidly, where H2O2 exists as its anion, hydroperoxide (HO2-). Interaction with the negatively charged sulfonic groups (SO3-) in the proton exchange polymer, Nafion, causes resistance to the mass transport of HO2- through the electrocatalyst layer. The HO2- can then accumulate, be degraded, and result in lower measured concentrations of H2O2 in the electrolyte