Charlotte, NC, United States
Charlotte, NC, United States

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In some embodiments, the invention provides a visibly detectable performance reference compound for use in a passive sampling device to detect an analyte of interest (and/or the amount of the analyte of interest) in an environment. In some embodiments, the invention provides a passive sampling device comprising a visibly detectable performance reference compound for use in detecting an analyte of interest (and/or the amount of the analyte of interest) in an environment. In some embodiments, the invention provides a kit comprising a first visibly detectable performance reference compound and a second visibly detectable performance reference compound for use in a passive sampling device to detect an analyte of interest (and/or the amount of the analyte of interest) in an environment. In some embodiments, invention provides a method to detect an analyte (and/or the amount of the analyte) in an environment using a passive sampling device comprising a visibly detectable performance reference compound.


A method destroys organic liquid contaminants contained in a plurality of below-ground volumes by smoldering combustion. The method applies heat to at least a portion of a first one of the volumes of organic liquid and forces oxidant into the first volume of organic liquid so as to initiate self-sustaining smoldering combustion of the first volume of organic liquid. The method may terminate the heat applied to the first volume of organic liquid. Next, the method modulates the flow of the oxidant into the first volume of organic liquid so as to cause at least a portion of the first volume of organic liquid to migrate and come into contact with another one of the volumes of organic liquid, so as to propagate the smoldering combustion. In an alternative embodiment, the flow of the oxidant may be modulated to establish a substantially stationary combustion front.


News Article | June 14, 2017
Site: www.prweb.com

Watershed Geo is pleased to announce that Dr. Ming Zhu has joined its elite staff of engineers. Zhu will assume the role of Director of Engineering Services, overseeing the company’s technical operations for existing products and the development of new product offerings. Dr. Zhu brings more than 11 years of consulting experience in geotechnical and geoenvironmental engineering. His expertise includes landfill design, contaminated sediment remediation, coal combustion residuals (CCR) impoundment closure, earth retaining structures, geotechnical instrumentation and numerical modeling. He was most recently Principal with Geosyntec Consultants prior to joining Watershed Geo. “I have watched Watershed Geo innovate and grow for several years now,” said Zhu. “They have solved long plaguing issues in landfill management by applying innovative, engineered solutions. I wanted to be a part of this culture of innovation that challenges status quo to dramatically improve a client’s operations and reduce their costs. That’s why I am here.” Well-known to the industry, Dr. Zhu is the author and co-author of more than 30 technical papers. He is currently serving on the American Society of Civil Engineers (ASCE) Geosynthetics Committee, ASCE Geotechnics of Soil Erosion Committee, and Transportation Research Board (TRB) Geo-Environmental Process (AFP40) Committee. He earned his Bachelor’s and Master’s Degrees in Hydraulic Engineering from Tsinghua University and his Doctoral Degree in Geotechnical Engineering from the University of Michigan. He is a registered Professional Engineer in Georgia. “Words can’t express how excited we are to have Dr. Zhu on board with us,” said Mike Ayers, CEO of Watershed Geo. “He’s one of the best in our field and his technical background and experience brings such a huge advantage to our company. His arrival is a testament to the performance of our products and shows the commitment of the company to be the leading technical resource for the industry. There is no doubt his expertise will be instrumental in many more innovations in solving our clients’ greatest challenges.” Dr. Zhu will join Watershed Geo’s current technical staff of hydrologists, geotechnical and civil engineers. Together, they have over 100 years of landfill experience (design, construction, maintenance and management), over 100 years of geosynthetic experience and over 100 individual sites managed through closure and post-closure. In addition to product support, this team provides free technical assistance to their clients in specification, design, installation and maintenance of landfill closures, and revetment of levees, dams, channels, slopes and shorelines. Based in Alpharetta, GA, Watershed Geo is an innovative environmental and civil technologies company specializing in engineered products that solve earth’s greatest challenges with solutions that reduce risks, require virtually no maintenance and stand the test of time. Watershed Geo’s solutions far exceed the performance of traditional methods, with validation through the highest levels of testing. Through best-in-class materials and extreme engineering, Watershed Geo’s goal is to unearth solutions that eliminate plaguing industry issues that reduce environmental and financial liabilities. Watershed Geo’s stable of products include but are not limited to: For more information, visit watershedgeo.com or ‘Follow us’ on Linkedin: https://www.linkedin.com/company-beta/5249763/


Li C.,Geosyntec Consultants | Zornberg J.G.,University of Texas at Austin
Journal of Geotechnical and Geoenvironmental Engineering | Year: 2013

Fiber reinforcement represents a promising alternative in projects involving localized repair of slopes and reinforcement of thin soil veneers, where planar reinforcement (e.g., with geotextiles and geogrids) is difficult to implement. Current design methodologies allow quantification of the shear strength of fiber-soil composites in terms of the parameters that independently characterize the soil matrix and fibers. The shear strength of fiber-reinforced soil is considered to have two components, including the shear strength of the soil matrix and the tension mobilized within the fibers. Triaxial compression tests and fiber pullout tests were conducted to evaluate how the fiber tension is mobilized for varying shear strain levels. The results of this evaluation provide insights into whether the shear strength of fiber-reinforced soil is governed by the peak or residual shear strength of unreinforced soil. A revision to existing design methodology is proposed in which the individual contribution of fibers and soil matrix is quantified based on the strain level. The appropriateness of using the peak or residual shear strength of the unreinforced soil for predicting the equivalent shear strength of fiber-soil composites is discussed based on strain compatibility considerations. © 2013 American Society of Civil Engineers.


Yeo S.-S.,Geosyntec Consultants | Hsuan Y.G.,Drexel University
Geotextiles and Geomembranes | Year: 2010

The tensile creep behavior of polyethylene-terephthalate (PET) and high density polyethylene (HDPE) geogrids was evaluated using five test methods: the short- and long-term stepped isothermal method (SIM), the short- and long-term time-temperature superposition (TTS), and the conventional method. SIM and TTS are acceleration tests using elevated temperatures. SIM uses a single specimen throughout all temperature steps in contrast to TTS in which a new specimen is employed for each temperature step. The test results indicate that at the same percentage of ultimate tensile strength, PET geogrid exhibited less creep deformation than the HDPE geogrid. The HDPE geogrid exhibited primary, secondary, and tertiary creep stages before rupture, whereas only primary creep and tertiary creep were detected in the PET geogrid. Furthermore, the strain rate of the primary creep stage was found to be independent of the applied loads for the PET geogrid, while it increased exponentially for the HDPE geogrid. The activation energies deduced from different accelerated creep tests were very similar for the PET geogrid. In contrast, the activation energies were higher from the short-term acceleration tests than from the long-term tests for the HDPE geogrid. The four-parameter Weibull model was able to predict the linear and non-linear creep behavior up to 100 years based on 10-h creep testing data. The creep reduction factor of 100 years design life was evaluated and higher values were resulted from the HDPE geogrid than from the PET geogrid. © 2009 Elsevier Ltd.


Espinoza R.D.,Geosyntec Consultants
International Journal of Project Management | Year: 2014

The rationale for using heuristics to establish a risk premium that is added to the risk-free rate to obtain the value of an investment is questioned and an alternative method, termed decoupled net present value (DNPV), is proposed. Rather than using utility theory concepts to decrease the value of uncertain cash flows, the risks associated with project cash flows are discretely quantified using insurance and contingent claim valuation concepts. Synthetic insurance premiums are designed to "protect" the value of expected cash flows which are treated as additional project costs. Because identified project risks are quantified in financial terms and treated as a real cost to the project, DNPV allows business executives to evaluate the effect on the value of the project of different risks and select management techniques that are deemed more effective. Hence, DNPV is both a valuation methodology and a risk management tool. © 2013 Elsevier Ltd and IPMA.


Patent
Geosyntec Consultants | Date: 2016-06-23

The invention provides a device and method to quantitatively measure concentrations of volatile organic compound vapors below the ground surface using a preferably fully passive device that is placed in a drilled or bored hole for a specified period of time, wherein the sampler constrains the uptake rate to match values that minimize or eliminate the starvation effect and provide acceptable sensitivity for most soil types as calculated via mathematical models.


Patent
Geosyntec Consultants | Date: 2012-04-26

Methods are provided for the volumetric reduction of organic liquids. The methods comprise admixing a porous matrix material with an organic liquid to produce a mixture, forcing oxidant through the mixture, and initiating a self-sustaining smoldering combustion of the mixture. Additional embodiments aggregate the organic liquid or porous matrix material or mixture thereof in an impoundment such as a reaction vessel, lagoon or matrix pile. Further embodiments utilize at least one heater to initiate combustion and at least one air supply port to supply oxidant to initiate and maintain combustion. Yet further embodiments comprise the batch addition of a fuel additive to the aggregate prior to smoldering to ensure that the ensuing smoldering combustion is self-sustaining or of the required temperature to reduce or remove other contaminants in the matrix or organic liquid such as heavy metals or asbestos.


Patent
Geosyntec Consultants | Date: 2013-09-10

The invention provides a device and method to quantitatively measure concentrations of volatile organic compound vapors below the ground surface using a preferably fully passive device that is placed in a drilled or bored hole for a specified period of time, wherein the sampler constrains the uptake rate to match values that minimize or eliminate the starvation effect and provide acceptable sensitivity for most soil types as calculated via mathematical models.


There is provided a method for achieving oxidation of organic contaminants held in low permeability soil and its contained pore water. The method comprises the supply and electromigration of an oxidant throughout the soil and pore water by means of an applied direct current via electrodes arrayed within the soil, followed by the heating of the soil by an applied alternating current using the identical electrodes.

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