Fate and transport of mercury in portland cement manufacturing facilities

The USEPA\u27s 2010 mercury rule for non-hazardous waste burning portland cement manufacturing facilities will significantly reduce mercury emissions in the United States, but represents a substantial regulatory challenge for the industry. Development of mercury control technologies for these facilities is difficult due to widely varying levels of mercury inputs and transient emissions caused by a poorly understood mechanism of mercury loop concentration. Determination of mercury concentrations in baghouse dust and kiln feed samples from within the internal mercury loop represents another difficulty due to diverse analytical procedures. Little published literature exists on mercury sorption and desorption from these materials. Without this data, the potential for this loop to serve as a mercury control and removal mechanism is not possible. To advance knowledge of mercury fate and transport in cement manufacture facilities, this study highlighted data gaps and research needs, optimized a digestion method for determination of mercury in kiln feed and baghouse dust, and identified and tracked mercury desorption, sorption, and internal concentration at specific points within a facility demonstrating an internal mercury loop

Case for Christian Higher Education: Two-Year Technical Programs, Too

The importance of today’s professional-technical vocations is critical to the collective work for Christ in today’s world. People serving in these fields are truly at the front lines, responding to God’s word with their hearts, minds, and hands. Posting about the need for Christian technical training from In All Things - an online hub committed to the claim that the life, death, and resurrection of Jesus Christ has implications for the entire world. http://inallthings.org/the-case-for-christian-higher-education-two-year-technical-programs-too

Photocatalytic degradation of NOx by concrete pavement containing TiO2

Emissions from motor vehicles cause the concentrations of nitrogen oxides (NOx) in the immediate vicinity of highways to be 30-100% higher than background concentrations. Photocatalytic pavements have been proposed to address this localized pollution problem. Bench-scale evaluation of environmental variables confirmed that nitric oxide (NO) oxidation rate positively correlated with influent NO concentration and irradiance and negatively correlated with relative humidity. However, comparison of the slope of these correlations found significant differences between this study and other published work. Slab water loss, a variable not investigated in prior work, positively correlated with NO oxidation rate at water losses of 0-2% of saturated mass, but negatively correlated at losses greater than 2%. A positive correlation was documented for slab temperature; this finding contrasts previous assertions which considered this variable insignificant. Overall, oxidation rates ranged from 6.2-57 nanomoles per square meter per second. This sensitivity demonstrates that selecting a field location requires exceptionally careful review of environmental conditions. Comparison of photocatalytic slabs of pervious concrete and mortar manufactured with the same photocatalytic cement and water-to-cement ratio found no evidence of a difference in NO oxidation rate at a confidence level greater than 90%. This finding contrasts previous speculation, which asserted superior pervious concrete performance due to increased specific surface area. In a second contrast to previous work, no evidence of a correlation was found between NO oxidation rate and photocatalytic layer depth in two-lift pervious slabs. Although pervious slabs were not superior to mortar slabs, they are another material that could address NOx pollution. Lab investigation of blinding by prevailing roadway pollutants did not find evidence of a substantial decrease in performance at normally observed field loadings. Reaction products did cause blinding; however, the performance decrease was asymptotic and a complete loss of activity was not observed. In disagreement with previous reports, preliminary results did not observe easy photoactivity regeneration. The first phase of an ongoing field study did not find evidence that NO concentration in a photocatalytic section was lower than NO concentration in a control section. The most probable explanations for this observation are excess vibration, which caused mixture segmentation, and insufficient NO oxidation rate

Deliberately and Meekly Serving Our Lord

The Jesus miracles demonstrate that he is Lord over all. Posting about Jesus, our role model, from In All Things - an online hub committed to the claim that the life, death, and resurrection of Jesus Christ has implications for the entire world. http://inallthings.org/deliberately-and-meekly-serving-our-lord

Distinctively Christian Engineering: Implementing Guiding Principles in our Civil Curriculum

At Dordt College, we work to make our motto, Soli Deo Gloria (glory to God alone), the organizing principle for all activities. In the Engineering Department, it is our responsibility to continue to shape our program to be holistic and Christ-centered in order to equip our students to serve the Lord obediently in engineering. To direct the development and modification of our engineering curriculum, we established a set of five distinctively Christian guiding principles for engineering. Setting the direction for this work required a grounding point. Therefore, in a subsequent manuscript we evaluated the extent to which these principles were already emphasized in our civil engineering curriculum. This evaluation found opportunities for curriculum improvements, the most pressing of which was developing our students’ understanding that that the world and everything in it was created for God’s glory. In this paper, we report on and critique our implementation of course activities that addressed the identified opportunities for curriculum improvement. This implementation included a common survey and targeted course activities. The survey provided an assessment of whether the guiding principles resonated with students at various points in their education. The activities were both linked to specific principles and course objectives and built upon activities in prior courses. Our critique of these early implementation steps provided evidence that the course activities helped our students understand and appreciate the guiding principles. However, further work needs to be done to translate this knowledge into a lifestyle where the principles guide all of our students’ engineering work

To Engage Creation

An engineer\u27s role in this service is to use science and technology to care for the entirety of creation - humans, other creatures, and the natural environment - in a way that both develops its potential and ensures that our activities do not impair its ability to flourish in the future. Posting about ­­­­­­­­a Christian perspective on engineering from In All Things - an online hub committed to the claim that the life, death, and resurrection of Jesus Christ has implications for the entire world. http://inallthings.org/to-engage-creation

Handleiding voor graslandvegetatiekartering

Bij deze methode van indelen, die het CABO hanteert, wordt gebruik gemaakt van bezettingspercentages van groepen plantesoorten, die een aanwijzing geven omtrent bepaalde groeiomstandighede

Hoogproductieve rassen van Engels raaigras geven ook bij een lage stikstofgift de beste benutting

Eerder onderzoek heeft aangetoond, dat bij de huidige stikstofbemestingsnorm een hogere droge-stof-productie samengaat met een betere N-benutting (zie Praktijkonderzoek december 1995). Met het oog op vermindering van de N-verliezen is het van belang te weten hoe de N-benutting van de verschillende rassen Engels raaigras zich onderling verhouden, zowel bij de huidige N-bemestingsnorm als bij een lager bemestingsniveau

Families of exact solutions of a 2D gravity model minimally coupled to electrodynamics

Three families of exact solutions for 2-dimensional gravity minimally coupled to electrodynamics are obtained in the context of ${\cal R}=T$ theory. It is shown, by supersymmetric formalism of quantum mechanics, that the quantum dynamics of a neutral bosonic particle on static backgrounds with both varying curvature and electric field is exactly solvable.Comment: 13 pages, LaTeX, to be published in JM

Benutting van herfstgras op veengrond door melkkoeien

On peat soils, milk production of autumn grazed dairy cows is often disappointing. Reduced palatability (i.e. a musty smell) of autumn grazed grass and consequently a reduced intake is considered as the main reason for the decline in milk production. A grazing experiment was conducted to compare 3 different strategies of grassland management within a rotational grazing system to improve the utilisation of autumn grazed grass by dairy cows for milk production. In the experiment, 36 mid-lactation dairy cows were used to form 3 balanced groups (“control”, “rationed” and “clean”) of 12 cows each. For all strategies, the grass cover was aimed at approximately 1500 kg DM/ha (rising plate meter sward height of 16 to 18 cm) at the moment of turning into the paddock