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McMillan N.J.,New Mexico State University | Montoya C.,New Mexico State University | Chesner W.H.,Chesner Engineering
Applied Optics | Year: 2012

Correlation of limestone beds is commonly based on a variety of features, including the age of the bed, the fossil assemblage, internal sedimentary structures, and the relationship to other units in the stratigraphy. This study uses laser-induced breakdown spectroscopy (LIBS) to correlate 16 limestone beds from Kansas, USA, using three multivariate techniques: (1) soft independent modeling of class analogy (SIMCA) classification, (2) a partial least squares regression, 1 variable (PLS-1) model in which the spectra are regressed against a matrix of the indicator variables 1 through 16, and (3) a matching algorithm that consists of a sequence of binary PLS-1 models. Each gravel-sized limestone particle was analyzed by one LIBS shot; ten spectra were averaged into a single spectrum for chemometric analysis. The entire spectrum (198-969 nm wavelength) is used for multivariate analysis; the only preprocessing is averaging. The SIMCA and PLS-1 models fail to discriminate among the beds, which are chemically similar. In contrast, the matching algorithm has a success rate of 95% to 96%, using half of the spectra to train the model and the other half of the spectra to validate it. However, 100% success can be accomplished by accepting the classification of the majority of spectra for a given bed as the correct classification. This study indicates that LIBS can be applied to complex geologic correlation problems and provide rapid, accurate results. © 2012 Optical Society of America.

Cross S.,Oklahoma State University | Chesner W.,Chesner Engineering | Justus H.,Chesner Engineering | Kearney E.,Chesner Engineering
Transportation Research Record | Year: 2011

Transportation engineers, planners, and policy makers are currently faced with the need to incorporate sustainability issues such as energy use, greenhouse gas emissions, and overall health impacts into the decision-making process. Life-cycle environmental analysis (LCEA) is one of the evolving tools available to assist in this effort. LCEA differs from traditional environmental analysis in that LCEA takes a more comprehensive look, or global perspective, at the environmental and resource burden of specific management decisions as opposed to traditional environmental analysis, which tends to focus almost exclusively on specific impacts at the activity or in the immediate geographic vicinity of the activity. The results of a study are presented: the computer program Pavement Life-Cycle Assessment Tool for Environmental and Economic Effects (PaLATE) was used to compare the environmental burden of employing cold in-place recycling with the environmental burden of the conventional maintenance options of a 3-in. mill and fill and a 3-in. hot-mix asphalt overlay. The results illustrate the potential of life-cycle environmental models to assist transportation officials in developing 21st century transportation policy as well as the current limitations associated with their use.

Chesner W.,Chesner Engineering | Stein C.,Chesner Engineering | Justus H.,Chesner Engineering | Kearney E.,Chesner Engineering | Cross S.,Oklahoma State University
Transportation Research Record | Year: 2011

In New York State, cold in-place recycling (CIPR) is one of a series of asphalt pavement rehabilitation options designed to extend the pavement service life. Recycling pavements with CIPR can decrease energy consumption and can reduce the environmental burden and cost associated with asphalt pavement rehabilitation. However, one drawback to increased use of CIPR has been uncertainty about expected service life and factors that affect long-term CIPR performance. These uncertainties generally limit the use of CIPR to low-volume pavements to minimize the exposure of CIPR-rehabilitated pavements to aggressive traffic conditions. A study examined the effect on service life of CIPR pavements in New York State of daily traffic, truck traffic, base thickness, base-plus-subbase thickness (total pavement thickness), geographical pavement location (environment and climate), and the condition of the pavement before CIPR rehabilitation. Data used in the analysis were compiled from the 2008 New York State Department of Transportation Pavement Management Group Highway Sufficiency Ratings Database, which represented 163 CIPR projects covering a pavement distance of 756 mi. CIPR rehabilitation can be expected to increase the service life of pavements, on average, by approximately 11 years. When CIPR is used on higher-trafficked (better-designed) pavements that have thicker supporting bases and subbases, its performance will benefit from thicker bases and the service life of the pavement will be extended.

Hadnagy E.,University of New Haven | Gardner K.H.,University of New Hampshire | Chesner W.H.,Chesner Engineering | Justus H.,Chesner Engineering | And 3 more authors.
Journal of Soils and Sediments | Year: 2014

Purpose: In situ sediment treatment technologies can be more economical alternatives than dredging and ex situ treatment; however, their development and application had been hindered due to uncertainties associated with the homogeneity of amendment delivery and mixing and the concern of contaminated sediment resuspension and amendment release into the water column. The purpose of this study was to evaluate the subaqueous amendment delivery and mixing efficiency of a novel pilot scale in situ sediment remediation system addressing these concerns. Materials and methods: The in situ sediment treatment system consisted of a hydraulically operated steel casing that provided contained conditions for amendment delivery and mixing to occur and the mixing tool housed by this casing. The mixing tool consisted of a hollow vertical shaft with horizontal mixing blades. The device was capable of delivering amendments to subaqueous sediments during continuous mixing in the downward or upward vertical direction. Activated carbon was used as a tracer to evaluate the efficiency of reagent delivery and mixing. The delivery and mixing system operation was defined by the following parameters: mixing speed, vertical descent or ascent speed, mixing time, total processing time, sediment mixing depth, activated carbon slurry injection volume, pumping flow rate for activated carbon, and pumping pressure for activated carbon. Results and discussion: Better amendment yield recoveries were observed at lower added activated carbon volumes, at higher mixing speeds, at lower pump flow rates, in case of thicker mixed sediment zones, and at horizontal locations closer to the center shaft. In general, poor amendment recoveries could be attributed to the limited capacity of the sediment pore space to accommodate the activated carbon slurry. Better recoveries close to the shaft might have occurred due to the fact that the amendment delivery pressure was not controlled and therefore was not constant through each reagent delivery port. The reagent stayed within the enclosure of the device, indicating that contained mixing conditions were achieved. The majority of the suspended sediment settled out fairly quickly from the overlying water column within the enclosure. Conclusions: The in situ remediation system showed potential in terms of successful amendment delivery and mixing into subaqueous sediments. Lower doses of activated carbon were mixed in more efficiently due to the limited availability of pore capacity and issues with powdered activated carbon retention in the sediment. The demonstration took place in sediments with large sand and gravel fractions; sediments containing larger silt and clay fractions are likely to behave differently in terms of sediment resuspension. © 2014, Springer-Verlag Berlin Heidelberg.

Chesner Engineering | Date: 2012-10-16

A method is described for providing a continuous flow of a target material past a laser to enable repeated firings of the laser beam at the material in a controlled and uniform fashion. The objective is to provide a means to characterize the target material using laser induced breakdown spectroscopy. The method can be employed in a laboratory or field environment providing improved methods for characterizing in real time the properties of bulk materials.

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