Laboratory and Field Data Needs for Site-Specific Repository Modeling

1983 ◽  
Vol 26 ◽  
Author(s):  
M.J. Apted
Keyword(s):  
Slow Release ◽  
Environmental Parameters ◽  
Nuclear Waste Repository ◽  
Relative Importance ◽  
Geochemical Processes ◽  
Laboratory Studies ◽  
Site Specific ◽  
Simple Matrix ◽  
And Migration ◽  
Efficient Program

ABSTRACTThe relative importance of material properties, geochemical processes, and environmental parameters affecting containment and release of radionuclides vary strongly as a function of time and spatial position within a nuclear waste repository located in basalt (NWRB). A simple matrix of spatial regions (Engineered-Barrier System, Disturbed-Rock Zone, Site System of the Controlled Access Zone) and time periods (Pre-emplacement, Containment, Isolation/Slow-release)can be used to identify the dominant processes that affect the containment, release, and migration of radionuclides. From this analysis, a directed and efficient program of field and laboratory studies can be conducted to obtain the data required to assess the feasibility of an NWRB and compliance with Federal regulatory criteria.

Studies on radionuclide transport behaviour–The next generation of in-situ experiments at the Grimsel Test Site

2009 ◽  
Vol 1193 ◽  
Author(s):  
Andrew James Martin ◽  
Ingo Blechschmidt
Keyword(s):  
Shear Zone ◽  
Diffusion Processes ◽  
Test Site ◽  
Core Material ◽  
Laboratory Studies ◽  
Grimsel Test Site ◽  
And Migration ◽  
Colloid Formation

AbstractTwo recent ongoing major projects at the Grimsel Test Site (GTS) (www.grimsel.com) that were initiated to simulate the long-term behaviour of radionuclides in the repository near-field and the surrounding host rock are presented: the Colloid Formation and Migration (CFM) project, which focuses on colloid generation and migration from a bentonite source doped with radionuclides and the Long-Term Diffusion (LTD) project, which aims at in-situ verification and understanding of the processes that control the long-term diffusion of repository-relevant radionuclides. So far, the CFM project has principally involved: development and implementation of a state-of-the-art sealing concept to control hydraulic gradients in a shear zone to imitate repository-relevant conditions; extensive laboratory studies to examine bentonite erosion and colloid formation in a shear zone; and, development of models to estimate colloid formation and migration. The next stage will be to assess the behavior of bentonite colloids generated from a radionuclide spiked bentonite source-term emplaced into the controlled flow field of the shear zone. This will be coupled with further extensive laboratory studies in order to refine and evaluate the colloid models currently used in performance assessments. The LTD project consists of: a monopole diffusion experiment where weakly sorbing and non-sorbing radionuclides (3H, 22Na, 131I, 134Cs) have been circulating and diffusing into undisturbed rock matrix since June 2007; experiments to characterise pore space geometry, including determination of in-situ porosity with 14C doped MMA resin for comparison with laboratory derived data; a study of natural tracers to elucidate evidence of long-term diffusion processes; and, an investigation of the in-situ matrix diffusion paths in core material from earlier GTS experiments. Future experiments will focus on diffusion processes starting from a water-conducting feature under realistic boundary conditions.

Viticultural terroirs in Stellenbosch, South Africa. II. The interaction of Cabernet-Sauvignon and Sauvignon Blanc with environment

OENO One ◽  
2008 ◽  
Vol 42 (4) ◽  
pp. 185 ◽  
Author(s):  
Victoria Anne Carey ◽  
Eben Archer ◽  
Gérard Barbeau ◽  
Dawid Saayman
Keyword(s):  
Growth Stage ◽  
Regression Tree ◽  
Environmental Parameters ◽  
Cabernet Sauvignon ◽  
Relative Importance ◽  
Sauvignon Blanc ◽  
Wind Exposure ◽  
Agronomic Potential ◽  
Weather Stations ◽  
High Relative Importance

<p style="text-align: justify;"><strong>Aims</strong>: A terroir can be defined as a grouping of homogenous environmental units, or natural terroir units, based on the typicality of the products obtained. Terroir studies therefore require an investigation into the response of grapevines to the natural environment.</p><p style="text-align: justify;"><strong>Methods and results</strong>: A network of plots of Sauvignon blanc and Cabernet Sauvignon were delimited in commercial vineyards in proximity to weather stations and their response monitored for a period of seven years. Regression tree methodology was used to determine the relative importance of the environmental and management related variables and to determine regression trees for each dependent variable. Excepting for scion clone, which had a high relative importance for bunch mass of Sauvignon blanc and yield to pruning mass index of Cabernet Sauvignon, no other nonenvironmental variable included in the analyses appeared to have a strong effect on grapevine performance and wine character. The performance of Cabernet-Sauvignon was related to the potassium content of the subsoil and climate (temperature and rainfall) of the season. The performance of Sauvignon blanc appeared to be related to soil texture, wind exposure and temperature of the site and season, both during the green berry growth stage and the month prior to ripening.</p><p style="text-align: justify;"><strong>Conclusions</strong>: From the results presented, it appears that environmental parameters have an overriding effect on the performance of both Cabernet Sauvignon and Sauvignon blanc but that these two cultivars react differently to environmental stimuli.</p><p style="text-align: justify;"><strong>Significance and impact of study</strong>: These results should contribute to the identification of viticultural terroirs with specific agronomic potential for Cabernet-Sauvignon and Sauvignon blanc.</p>

Analysis of Impact Loads on a Self-Elevating Unit During Jacking Operation

2017 ◽  
Vol 139 (3) ◽  
Author(s):  
Jonas W. Ringsberg ◽  
Viktor Daun ◽  
Fredrik Olsson
Keyword(s):  
Simulation Model ◽  
Deformation Behavior ◽  
Environmental Parameters ◽  
Time Domain Analysis ◽  
Offshore Wind ◽  
Soil Deformation ◽  
Site Specific ◽  
Impact Forces ◽  
Capacity Theory ◽  
Vessel Motion

A method is presented that enables the analysis of weather window assessments for the installation and retrieval phases of a self-elevating unit (SEU). The method takes site-specific parameters, defined as soil type and water depth, into account in addition to vessel-specific and environmental parameters. The inclusion of site-specific parameters is the novel contribution compared to assessment methodologies used today. A simulation model is presented that incorporates a coupled nonlinear time-domain analysis of vessel motion and soil–structure interaction. Soil deformation behavior during impact is described by resistance curves based on a bearing capacity theory. A structural evaluation criterion against which impact forces are compared is used for weather window assessments. The simulation model is applied on a case study utilizing different soil types to study impact forces and the capacity of the structure for withstanding such impacts and eventually performing a weather window assessment. The results show that the jacking operation can be divided into two phases when it comes to loads on the spudcan: a phase dominated by vertical forces followed by a phase dominated by horizontal forces. It is found that including soil deformation behavior is of paramount importance to the magnitude of the resulting impact forces and that class-recommended practice does indeed produce rather large force estimates. Thus, assessments where site-specific parameters are incorporated could definitely increase the operable weather window for SEUs, and, consequently, increase the economic competitiveness of, for example, the offshore wind industry.

scholarly journals FIELD MEASUREMENTS AND SWASH PARAMETERIZATION ON BEACHES

2018 ◽  
pp. 23
Author(s):  
Paula Gomes Da Silva ◽  
Raúl Medina ◽  
Mauricio González ◽  
Roland Garnier
Keyword(s):  
Environmental Parameters ◽  
Field Measurements ◽  
Wave Runup ◽  
Wave Processes ◽  
Site Specific ◽  
Erosion Risk ◽  
Sediment Size ◽  
Water Edge ◽  
Offshore Wave ◽  
Empirical Approaches

The wave runup, defined as the vertical oscillation of the water edge at the coast, is commonly used as criterion for coastal design projects and flooding/erosion risk analysis. Due to the complexity of nearshore wave processes, most runup studies are based on empirical approaches which directly relate these oscillations to the beach and offshore wave characteristics. However, there is still considerable debate about just how runup is related to these environmental parameters, as well as about the range of application of empirical models due to site specific conditions. Recent works emphasized the importance of including site specific conditions to reduce the scatter in available parameterizations. Parameters related to beach characteristics like the sediment size, the amount of reflection, wave spectral shape and morphodynamic beach state may improve runup predictions (Poate et al., 2016, Guza and Feddersen, 2012).

scholarly journals Cytoprotection, Genoprotection, and Dermal Exposure Assessment of Chitosan-Based Agronanofungicides

Pharmaceutics ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 497
Author(s):  
Farhatun Najat Maluin ◽  
Mohd Zobir Hussein ◽  
Nor Azah Yusof ◽  
Abu Seman Idris ◽  
Leona Daniela Jeffery Daim ◽  
...  
Keyword(s):  
Exposure Assessment ◽  
Health Risks ◽  
Slow Release ◽  
Dermal Exposure ◽  
Lung Cells ◽  
Site Specific ◽  
Cell Death Assay ◽  
Dermal Irritation ◽  
High Bioavailability ◽  
Direct Toxicity

Health risks which result from exposure to pesticides have sparked awareness among researchers, triggering the idea of developing nanoencapsulation pesticides with the aim to enhance cytoprotection as well as genoprotection of the pesticides. In addition, nanocapsules of pesticides have slow release capability, high bioavailability, and site-specific delivery, which has attracted great interest from researchers. Hence, the objective of this work is to synthesize a nanoformulation of a fungicide of different sizes, namely, chitosan-hexaconazole nanoparticles (18 nm), chitosan-dazomet nanoparticles (7 nm), and chitosan-hexaconazole-dazomet nanoparticles (5 nm), which were then subjected to toxicological evaluations, including cytotoxicity, genotoxicity, cell death assay, and dermal irritation assays. Incubation of chitosan-based nanofungicides with V79-4 hamster lung cell did not reveal cytotoxicity or genotoxicity, potentially suggesting that encapsulation with chitosan reduces direct toxicity of the toxic fungicides. Meanwhile, pure fungicide revealed its high cytotoxic effect on V79-4 hamster lung cells. In addition, dermal exposure assessment on rabbits revealed that chitosan-hexaconazole nanoparticles are classified under corrosive subcategory 1C, while chitosan-dazomet nanoparticles are classified under corrosive subcategory 1B. Moreover, both chitosan-hexaconazole nanoparticles and chitosan-dazomet nanoparticles are classified as causing mild irritation.

Reference Strength of Ice to be Used in Designing Offshore Structures

1988 ◽  
Vol 110 (4) ◽  
pp. 414-420
Author(s):  
A. L. Tunik
Keyword(s):  
Compressive Strength ◽  
Reference Value ◽  
Environmental Parameters ◽  
Offshore Structures ◽  
Observation Data ◽  
Offshore Structure ◽  
Site Specific ◽  
Acceptable Accuracy ◽  
Simplified Method ◽  
Ice Strength

The strength of ice depends on many factors. If they are known, the strength can be predicted with an acceptable accuracy. When designing an offshore structure, a designer usually has to select appropriate values of ice strength from incomplete, uncertain and random observation data for the site-specific ice environment. In this paper, a simplified method of selecting such values is described. A reference value of compressive strength is presented as an analytical function of averaged site-specific environmental parameters and offshore structure dimensions which are usually available to the designer.

Energetic consequences of metabolic depression in tropical and temperate-zone lizards

1999 ◽  
Vol 47 (2) ◽  
pp. 133 ◽  
Author(s):  
Keith A. Christian ◽  
Gavin S. Bedford ◽  
Timothy J. Schultz
Keyword(s):  
Energy Savings ◽  
Environmental Parameters ◽  
Thermal Acclimation ◽  
Temperate Zone ◽  
Energy Budgets ◽  
Tropical Species ◽  
Metabolic Depression ◽  
Laboratory Studies ◽  
Conservation Of Energy ◽  
Dry Tropics

One response of ectothermic animals to periods of inactivity is inverse acclimation, or metabolic depression, which results in the conservation of energy. Most studies of metabolic depression and acclimation have involved temperate-zone species, and the information from tropical species has been largely restricted to laboratory studies that failed to demonstrate thermal acclimation of metabolism. Recently, metabolic depression has been shown in several species of reptiles from the wet-dry tropics of northern Australia during the dry season. We review existing data on the energy budgets of temperate and tropical species during periods of inactivity and make calculations of energy saved due to metabolic depression across a range of temperatures. Because tropical species experience relatively high temperatures during periods of inactivity, they have a greater potential for energy savings, any enhancement of their metabolic depression is disproportionately advantageous with respect to energy savings, and in some species metabolic depression is probably essential for survival. Thus, we would expect metabolic depression to be well developed in some tropical reptiles. The lack of thermal acclimation in laboratory studies indicates that environmental parameters other than temperature (such as food or water) may initiate metabolic depression in tropical species. Higher temperatures, however, magnify the energy savings accomplished by metabolic depression.

scholarly journals Tracking Pseudomonas aeruginosa transmissions due to environmental contamination after discharge in ICUs using mathematical models

2018 ◽  
Author(s):  
Thi Mui Pham ◽  
Mirjam Kretzschmar ◽  
Martin Bootsma ◽  
Xavier Bertrand ◽  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Environmental Contamination ◽  
Control Strategies ◽  
Bacterial Load ◽  
Environmental Parameters ◽  
University Hospital ◽  
Relative Importance ◽  
Quantitative Evidence ◽  
Cross Transmission ◽  
Healthcare Associated

Pseudomonas aeruginosa (P. aeruginosa) is an important cause of healthcare-associated infections, particularly in immunocompromised patients. Understanding how this multi-drug resistant pathogen is transmitted within intensive care units (ICUs) is crucial for devising and evaluating successful control strategies. While it is known that moist environments serve as natural reservoirs for P. aeruginosa, there is little quantitative evidence regarding the contribution of environmental contamination to its transmission within ICUs. Previous studies on other nosocomial pathogens rely on deploying specific values for environmental parameters derived from costly and laborious genotyping. Using solely longitudinal surveillance data, we estimated the relative importance of P. aeruginosa transmission routes by exploiting the fact that different routes cause different pattern of fluctuations in the prevalence. We developed a mathematical model including endogenous colonization, cross-transmission and environmental contamination. Patients contribute to a pool of pathogens by shedding bacteria to the environment. Natural decay and cleaning of the environment lead to a reduction of that pool. By assigning the bacterial load shed during an ICU stay to cross-transmission, we were able to disentangle environmental contamination during and after a patient’s stay. Based on a data-augmented Markov Chain Monte Carlo method the relative importance of the considered acquisition routes is determined for two ICUs of the University hospital in Besancon (France). We used information about the admission and discharge days, screening days and screening results of the ICU patients. Both cross-transmission and endogenous transmission play a significant role in the transmission process in both ICUs. In contrast, only about $1\%$ of the total transmissions were due to environmental contamination after discharge. Improved cleaning of the environment after discharge would have only a limited impact regarding the prevention of P. aeruginosa infections in the two considered ICUs. Our model was developed for P. aeruginosa but can be easily applied to other pathogens as well.

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