scholarly journals THE BROOKHAVEN NATIONAL LABORATORY PERFLUOROCARBON TRACER TECHNOLOGY: A PROVEN AND COST EFFECTIVE METHOD TO VERIFY INTEGRITY AND MONITOR LONG TERM PERFORMANCE OF WALLS, FLOORS, CAPS, AND COVER SYSTEMS.

2002 ◽  
Author(s):  
J. HEISER ◽  
T. SULLIVAN
Keyword(s):  
National Laboratory ◽  
Cost Effective ◽  
Brookhaven National Laboratory ◽  
Cost Effective Method ◽  
Cover Systems ◽  
Long Term Performance ◽  
Term Performance

Rail Highway Grade Crossing Roughness Quantitative Measurement Using 3D Technology

2014 ◽  
Author(s):  
Teng (Alex) Wang ◽  
Reginald R. Souleyrette ◽  
Daniel Lau ◽  
Peng Xu
Keyword(s):  
Quantitative Method ◽  
Cost Effective ◽  
Actual Condition ◽  
Subjective Rating ◽  
3D Surface ◽  
Grade Crossing ◽  
Long Term Performance ◽  
Term Performance

Quality of surface is an important aspect affecting both the safety and the performance of at-grade rail-highway crossings. Roughness may increase the risk of crashes for both trains and automobiles. Varying grades in crossing profiles increase the likelihood of high-centered crossing collisions between train and truck [1]. The US DOT Railroad Highway Grade Crossing Handbook [2] suggests that rough surfaces could distract a driver’s attention from oncoming trains and that the unevenness of the crossing could result in a driver losing control of their vehicle resulting in a crash. No quantitative method currently exists to quickly and economically assess the condition of rail crossings in order to evaluate the long term performance of crossings and set a quantitative trigger for their rehabilitation. The conventional method to measure the surface of quality of crossings is based on expert judgment, whereby crossing surfaces are classified as poor, fair or good after an inspector visits and drives over the crossing. However, actual condition of the crossing could be different from the subjective rating. Poor condition rating crossings may not always present the most cost-effective locations for preventive maintenance to lower overall life-cycle costs. Conventional ratings may derive from driving a passenger car of pickup once over the crossing. Effects of various speed, on various vehicles (suspension), and at various places (laterally) cannot be determined or even estimated except at the smoothest of crossings. A quantifiable and extensible procedure is desired. With rapid advances in computer science, 3D sensing and imaging technologies, it seems logical that a cost-effective quantitative method could be developed to determine the need to rehabilitate rail crossings and assess long term performance. Fundamental to the quantification of crossing condition is the acquisition of an accurate 3D surface model of the crossing in its present state. This paper reports on the development of an accurate, low cost and readily deployable sensor capable of rapid collection of this 3D surface. The research is seen as a first step towards automating the crossing inspection process, ultimately leading to the quantification and estimation of future performance of rail crossing.

Experimental study on the performance of light and dense backfills

2011 ◽  
Vol 48 (2) ◽  
pp. 214-225 ◽  
Author(s):  
Sumi Siddiqua ◽  
James Blatz ◽  
Greg Siemens
Keyword(s):  
Mechanical Behaviour ◽  
Cost Effective ◽  
Strain Behaviour ◽  
Triaxial Cell ◽  
Important Approach ◽  
Shear Characteristics ◽  
Long Term Performance ◽  
Term Performance ◽  
Sealing Materials

Numerical modeling is a cost-effective and important approach to examine the long-term performance of engineered materials. However, to identify the appropriate constitutive model for a particular material it is necessary to measure physical properties in a laboratory. Laboratory experiments provide the data from which the input parameters for the selected model can be interpreted. This paper studies the mechanical behaviour of two clay-based sealing materials — light backfill and dense backfill — recommended for use in disposal of nuclear waste in a proposed Canadian repository. Test specimens of light and dense backfills were saturated in a triaxial cell and then subjected to specified isotropic and shearing stress paths to measure consolidation and shear characteristics. The triaxial results are interpreted in a critical state context. The light backfill results suggest that it has similar stress–strain behaviour to a bentonite–sand buffer, which has a similar composition, but different preparation procedures and design requirements. Results from testing of dense backfill indicate that it is a much stiffer and stronger material than light backfill. Dense backfill is expected to provide mechanical support to the used-fuel container and other sealing components of the Canadian repository, and the mechanical behaviour of dense backfill satisfies these requirements.

Pond and wetland treatment

2003 ◽  
Vol 48 (5) ◽  
pp. 1-8 ◽  
Author(s):  
R.H. Kadlec
Keyword(s):  
Temperature Dependence ◽  
Rate Constants ◽  
Cost Effective ◽  
Fecal Coliforms ◽  
First Order ◽  
Loading Rates ◽  
Wetland Treatment ◽  
Long Term Performance ◽  
Term Performance

Wetlands are in use as adjuncts to wastewater treatment lagoons at many north temperate locations. Performance data for 21 systems show median removals of 67, 61, 61, 48 and 99.8% for TSS, BOD, NH4-N, TP and fecal coliforms, respectively. Hydraulic loading rates range from 0.14 to 55 cm/d, areas from 0.02 to 200 ha, and latitudes from 30 to 54°N. Calibrations of first order models with temperature dependence show that rate constants vary from seasonal dependence at low loadings to temperature dependence at high loadings for ammonia. Phosphorus rate constants display seasonal, not temperature effects. BOD and TSS are not affected by season. Wetland rate constants are larger than those for lagoons for all constituents. The optimal winter operating strategy, if hydraulics allow, is partial storage during frozen months, coupled with winter use of the wetlands. The use of FWS wetlands for polishing lagoon effluents is cost effective when land availability is not drastically constrained. Many systems have been in operation long enough to demonstrate sustainable long-term performance. Infiltration beds are potentially a valuable addition to ponds and wetlands.

Analysis and Optimization of a Multi-Stage Solar Collector System

1986 ◽  
Vol 108 (3) ◽  
pp. 192-198
Author(s):  
J. M. Gordon ◽  
C. Saltiel
Keyword(s):  
Control Strategies ◽  
Cost Effective ◽  
Constant Load ◽  
Analytic Method ◽  
Climatic Data ◽  
Collector System ◽  
Multi Stage ◽  
Cost Effective Method ◽  
Long Term Performance ◽  
Term Performance

We present an analytic method for predicting the long-term performance of solar energy systems with more than one collector brand (“multi-stage” systems). This procedure enables the designer to determine the most cost-effective method of combining different collector brands for a given load. Although our derivations pertain to solar systems for constant load applications and/or near constant collector operating threshold, they can also be used for conventional multi-pass designs. The problems of excess energy delivery, and of various collector on/off control strategies, are taken into account. Our results are simple closed-form expressions whose evaluation requires readily-available average climatic data, and load and collector characteristics. The analytic method is illustrated by a solved example which shows that significant savings can be realized by combining different collector brands for a given application (multi-staging).

scholarly journals Porous Fe0/C ceramsites for removal of aqueous Pb(ii) ions: equilibrium, long-term performance and mechanism studies

RSC Advances ◽  
2018 ◽  
Vol 8 (45) ◽  
pp. 25445-25455 ◽  
Author(s):  
Pingfeng Fu ◽  
Xiaofeng Lin ◽  
Zihao Chen
Keyword(s):  
Cost Effective ◽  
Paper Mill ◽  
Paper Mill Sludge ◽  
Long Term Performance ◽  
Term Performance ◽  
Performance And Mechanism

Cost-effective Fe0/C microelectrolysis ceramsites were fabricated from magnetite, coal and paper mill sludge with high long-term performance in the removal of Pb(ii) ions.

scholarly journals Valorisation of Partially Oxidized Tailings in a Cover System to Reclaim an Old Acid Generating Mine Site

Minerals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 987
Author(s):  
Gabrielle Dublet-Adli ◽  
Thomas Pabst ◽  
Gudny Okkenhaug ◽  
Christian Sætre ◽  
Anna M. Vårheim ◽  
...  
Keyword(s):  
Capillary Barrier ◽  
Wetting And Drying ◽  
Barrier Effects ◽  
Cover Systems ◽  
Control Column ◽  
Geochemical Behaviour ◽  
Long Term Performance ◽  
Term Performance ◽  
Leachate Water

The reclamation of acid-generating mine tailings typically involves building cover systems to limit interactions with water or oxygen. The choice of cover materials is critical to ensure long-term performance, and partly determines the environmental footprint of the reclamation strategy. The objective of this research was to evaluate if tailings pre-oxidized on-site could be used in cover systems. Column experiments were performed to assess the effectiveness of a cover with capillary barrier effects (CCBE), where the moisture retention layer (MRL) was made of pre-oxidized tailings with little to no remaining sulfides (LS tailings). The columns were submitted to regular wetting and drying cycles, and their hydrological and geochemical behaviour was monitored for 510 days. The LS tailings showed satisfying hydrological properties as an MRL and remained saturated throughout the test. The concentrations of Cu in the drainage decreased by more than two orders of magnitude compared to non-covered tailings. In addition, the pH increased by nearly one unit compared to the control column, and Fe and S concentrations decreased by around 50%. Despite these improvements, the leachate water remained acidic and contaminated, indicating that acid drainage continued to be generated despite a hydrologically efficient CCBE.

Performance-based specifications for pavements

1991 ◽  
Vol 18 (6) ◽  
pp. 1054-1061 ◽  
Author(s):  
P. Kuzyk ◽  
R. C. G. Haas ◽  
R. W. Cockfield
Keyword(s):  
Risk Factors ◽  
Key Words ◽  
Current Practice ◽  
Cost Effective ◽  
Pavement Performance ◽  
Substantial Portion ◽  
Actual Performance ◽  
Long Term Performance ◽  
Term Performance

Pavements represent a very substantial portion of the public's investment in infrastructure. It is essential that this investment be preserved through cost-effective planning, design, and maintenance. One way of achieving this is through the use of long-term performance-based specifications. This paper first describes the current practice for pavement specification. For the most part, these specifications are "recipe" orientated. Very specific requirements are set for procedures, such as compaction, or as constructed properties such as density. With the proposed system, the contractor would be required to warranty the actual performance of the pavement over an extended term. The paper describes the overall scope of the system, its key elements and advantages, and the major risk factors. As well, the measures that can be used to characterize performance and a model for estimating performance are identified. A stochastic formulation of the model is used to present a method of determining the risk to the contractor based on a design example. Finally, the paper explores some of the concerns associated with the implementation of the system and how these concerns might be addressed. Key words: long-term warranties, pavement contracting, pavement performance.

The Long-Term Performance of Concrete in Nuclear Applications

2005 ◽  
Author(s):  
Denzel L. Fillmore ◽  
Philip L. Winston ◽  
Sheryl L. Morton ◽  
Cecelia R. Hoffman ◽  
Leo A. Van Ausdeln ◽  
...  
Keyword(s):  
National Laboratory ◽  
Concrete Deterioration ◽  
Structural Functions ◽  
The Pacific ◽  
Increasing Temperature ◽  
Long Term Performance ◽  
Term Performance ◽  
Higher Doses ◽  
Nuclear Applications

The Idaho National Laboratory investigated long-term concrete performance for nuclear applications. Scientists searched the open literature for information on the effects of heat and radiation. They also examined the concrete shield of the Pacific Sierra Nuclear Ventilated Storage Cask (VSC-17) for concrete deterioration and loss of shielding. The literature search revealed that low doses, <109 n/cm2 or <1011 Rad gamma, of radiation over periods less than 50 years do not appear to significantly affect concrete. Exposure over 100 years was not studied. The effects of higher doses of radiation are not as clear. Generally, the threshold of degradation is 95°C, and degradation increases with increasing temperature and time. In 15 years of VSC-17 use, there is no apparent effect from environment, radiation, or temperature that has adversely affected the shielding or structural functions, although there has been some minor cracking of the concrete.

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