scholarly journals Advective Displacement Method for the Characterisation of Pore Water Chemistry and Transport Properties in Claystone

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Urs Mäder
Keyword(s):  
Transport Properties ◽  
Pore Water ◽  
Material Selection ◽  
Construction Material ◽  
Core Sample ◽  
Displacement Method ◽  
Multicomponent Transport ◽  
Argillaceous Rocks ◽  
Exchange Processes ◽  
Hydraulic Gradients

The advective displacement method applies large hydraulic gradients to a confined rock core sample to yield small aliquots of the preserved in situ pore water, applicable to aquitard rocks with hydraulic conductivities as low as 10−14 m/s. Examples from argillaceous rocks indicate that only minor artefacts are induced and that analytical methods optimized for small aliquots provide a comprehensive chemical and isotopic characterisation. Multicomponent transport properties are derived from extending experimental time and using a traced artificial pore water for injection. Examples include quantification of the anion exclusion effect that can even resolve a small difference between transport properties for chloride and bromide in claystone. Controls by mineral saturation and cation exchange processes are also constrained by data from this approach. Technical details are provided for construction, material selection, components, sensors, and analytical issues.

scholarly journals A Prototype Expert System for the Selection of Road Construction Materials

2007 ◽  
Vol 4 (1) ◽  
pp. 1
Author(s):  
S. Hassim ◽  
K.T. Teh ◽  
R. Muniandy ◽  
H. Omar ◽  
A. Hassan
Keyword(s):  
Expert System ◽  
Knowledge Base ◽  
Material Selection ◽  
Construction Material ◽  
Construction Materials ◽  
Road Construction ◽  
Statistical Testing ◽  
Factors Affecting ◽  
Microsoft Access ◽  
Programming Tool

A prototype for an expert system in road construction material selection system, which is based on the outcomes of Friedman and multiple comparisons statistical methods was developed. The outcomes were acquired through questionnaires from selected pavement experts. The factors affecting pavement materials under each particular site condition were incorporated into the specific rules of the system. The system knowledge-base was extracted from the statistical testing outcomes and then rearranged and compiled prior to the development of the system. Visual Basic 6.0 was adopted as the programming tool for development of the system, while the knowledge-base of the separate system was kept in Microsoft Access 2000. The prototype expert system can be used to emulate part of the professional reasoning capabilities based on the knowledge of a pavement expert or a specialist to solve problems on materials selection. The system can help road designers to improve their professional ability to evaluate all available materials even before carrying out any laboratory tests.

scholarly journals The transport of liquids in softwood: timber as a model porous medium

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
H. C. Burridge ◽  
G. Wu ◽  
T. Reynolds ◽  
D. U. Shah ◽  
R. Johnston ◽  
...  
Keyword(s):  
Experimental Data ◽  
Porous Medium ◽  
Fluid Flow ◽  
Transport Properties ◽  
Pore Space ◽  
Construction Material ◽  
Sustainable Construction ◽  
Natural Material ◽  
Full Potential ◽  
Treatment Processes

AbstractTimber is the only widely used construction material we can grow. The wood from which it comes has evolved to provide structural support for the tree and to act as a conduit for fluid flow. These flow paths are crucial for engineers to exploit the full potential of timber, by allowing impregnation with liquids that modify the properties or resilience of this natural material. Accurately predicting the transport of these liquids enables more efficient industrial timber treatment processes to be developed, thereby extending the scope to use this sustainable construction material; moreover, it is of fundamental scientific value — as a fluid flow within a natural porous medium. Both structural and transport properties of wood depend on its micro-structure but, while a substantial body of research relates the structural performance of wood to its detailed architecture, no such knowledge exists for the transport properties. We present a model, based on increasingly refined geometric parameters, that accurately predicts the time-dependent ingress of liquids within softwood timber, thereby addressing this long-standing scientific challenge. Moreover, we show that for the minimalistic parameterisation the model predicts ingress with a square-root-of-time behaviour. However, experimental data show a potentially significant departure from this $$\sqrt{{\boldsymbol{t}}}$$t behaviour — a departure which is successfully predicted by our more advanced parametrisation. Our parameterisation of the timber microstructure was informed by computed tomographic measurements; model predictions were validated by comparison with experimental data. We show that accurate predictions require statistical representation of the variability in the timber pore space. The collapse of our dimensionless experimental data demonstrates clear potential for our results to be up-scaled to industrial treatment processes.

Hydrological exchange and sediment characteristics in a riverbank: relationship between heavy metals and invertebrate community structure

1995 ◽  
Vol 52 (10) ◽  
pp. 2084-2097 ◽  
Author(s):  
Janine Gibert ◽  
Sandrine Plénet ◽  
Pierre Marmonier ◽  
Vladimir Vanek
Keyword(s):  
Heavy Metals ◽  
Hydraulic Conductivity ◽  
Oxygen Content ◽  
Pore Water ◽  
Filtration Efficiency ◽  
Bank Filtration ◽  
Low Oxygen ◽  
Rhône River ◽  
Metal Concentrations ◽  
Hydraulic Gradients

The first metre of bed sediments of the Rhône River functions as a filter for fluxes of heavy metals and epigean organisms between surface and interstitial environments. To study the efficacy of this bank filtration, three sampling stations were established at increasing distances from pumping wells, resulting in a gradient of hydraulic characteristics. Station A, a permanent downwelling area with very high hydraulic gradients, low hydraulic conductivity, low oxygen content, and rather high metal concentrations contained a fauna exclusively composed of epigean organisms. At station B, intermediate hydraulic gradients, high hydraulic conductivity near the surface, and variable direction of water exchanges resulted in well-oxygenated pore water and a diversified fauna with hypogean and epigean species. Finally, at station C, low hydraulic gradient, low hydraulic conductivity, low water exchange, and high sediment metal concentrations resulted in low pore-water oxygen concentrations and low interstitial fauna density and diversity. At this site, low oxygen content and low biodiversity were related to the clogging of shallow sediments and low filtration efficiency. Thus, bank filtration efficiency, a property that depends mainly on natural or human-induced hydraulic gradients and sediment granulometry, determines pore-water chemistry, metal distribution, and faunal composition in the shallow interstitial environments of the Rhône River.

scholarly journals Rock Pore Structure as Main Reason of Rock Deterioration

2014 ◽  
Vol 36 (1) ◽  
pp. 79-88 ◽  
Author(s):  
Martin Ondrášik ◽  
Miloslav Kopecký
Keyword(s):  
Tensile Strength ◽  
Pore Structure ◽  
Water Absorption ◽  
Pore Water ◽  
Construction Material ◽  
Adsorbed Water ◽  
Rock Properties ◽  
Exclusion Criterion ◽  
Hydraulic Pressure ◽  
Freeze Thaw

Abstract Crashed or dimensional rocks have been used as natural construction material, decoration stone or as material for artistic sculptures. Especially old historical towns not only in Slovakia have had experiences with use of stones for construction purposes for centuries. The whole buildings were made from dimensional stone, like sandstone, limestone or rhyolite. Pavements were made especially from basalt, andesite, rhyolite or granite. Also the most common modern construction material - concrete includes large amounts of crashed rock, especially limestone, dolostone and andesite. However, rock as any other material if exposed to exogenous processes starts to deteriorate. Especially mechanical weathering can be very intensive if rock with unsuitable rock properties is used. For long it had been believed that repeated freezing and thawing in relation to high absorption is the main reason of the rock deterioration. In Slovakia for many years the high water absorption was set as exclusion criterion for use of rocks and stones in building industry. Only after 1989 the absorption was accepted as merely informational rock property and not exclusion. The reason of the change was not the understanding of the relationship between the porosity and rock deterioration, but more or less good experiences with some high porous rocks used in constructions exposed to severe weather conditions and proving a lack of relationship between rock freeze-thaw resistivity and water absorption. Results of the recent worldwide research suggest that understanding a resistivity of rocks against deterioration is hidden not in the absorption but in the structure of rock pores in relation to thermodynamic properties of pore water and tensile strength of rocks and rock minerals. Also this article presents some results of research on rock deterioration and pore structure performed on 88 rock samples. The results divide the rocks tested into two groups - group N in which the pore water does not freeze even when the temperature decreases to -20 ºC, and the second group F in which the pore water freezes. It has been found that the rocks from group N contain critical portion of adsorbed water in pores which prevents freezing of the pore water. The presence of adsorbed water enables thermodynamic processes related to osmosis which are dominantly responsible for deterioration of rocks from group N. A high correlation (R = 0.81) between content of adsorbed water and freeze-thaw loss was proved and can be used as durability estimator of rocks from group N. The rock deterioration of group F is caused not only by osmosis, but also by some other processes and influences, such as hydraulic pressure, permeability, grain size, rock and mineral tensile strength, degree of saturation, etc., and the deterioration cannot be predicted yet without the freeze-thaw test. Since the contents of absorbed water and ratio between adsorbed and bulk water (of which the absorbed water consists) is controlled by the porosity and pore structure, it can be concluded that the deterioration of some rocks is strongly related to rock pore structure.

scholarly journals Perceptions, Attitudes, and Interests of Architects in the Use of Engineered Wood Products for Construction: A Review

2021 ◽  
Author(s):  
Hüseyin Emre Ilgın ◽  
Markku Karjalainen
Keyword(s):  
Energy Use ◽  
Material Selection ◽  
Construction Material ◽  
Primary Energy ◽  
Wood Products ◽  
Biobased Materials ◽  
Wood Construction ◽  
Engineered Wood Products ◽  
Engineered Wood ◽  
The Impact

Increased use of engineered wood products (EWPs) and thus decreasing share of non-biobased materials such as concrete reduces the impact of buildings on the climate by mitigating the primary energy use and greenhouse gas emissions in construction. A construction project includes many parameters, where the selection of construction material is one of the crucial decisions with its numerous criteria e.g. cost, strength, environmental impact. Furthermore, this complicated process includes different parties such as architects, engineers, contractors. Architects are among the key decision-makers in material selection, and their perceptions influence what they propose and hence an increase in wood construction. In literature, many studies have been conducted on the technological, ecological, economic aspects of EWPs, while limited studies are focusing on EWPs for construction from stakeholders’ perspective. In this chapter, architects’ attitudes towards the use of EWPs in buildings were scrutinized.

scholarly journals Wood use and kayak construction: Material selection from the perspective of carpentry

2013 ◽  
Vol 36 (1) ◽  
pp. 49-62 ◽  
Author(s):  
Matthew Walls
Keyword(s):  
Material Selection ◽  
Construction Material ◽  
Experimental Archaeology ◽  
The Arctic ◽  
Archaeological Sites

Abstract Although the natural availability and quality of wood is variable across the Arctic, there is great continuity in how it was traditionally used. This article considers the value of wood to Arctic peoples and the criteria that would distinguish the utility of different pieces. The topic is explored in the case of kayak construction, one of the most complex carpentry tasks that can be inferred from many archaeological sites. Numerous types of kayaks were built in several periods by a variety of peoples using very different toolkits. Using both ethnographic and archaeological examples, it is shown that this technology everywhere shared several key stages of construction. Within these stages, specific carpentry tasks defined the criteria that all kayak builders used to select wood. By exploring the value of wood to Arctic peoples for carpentry, this article demonstrates the potential for understanding wood use through experimental archaeology.

scholarly journals Mineralogical and geochemical variation in stream sediments impacted by acid mine drainage is related to hydro-geomorphic setting

Elem Sci Anth ◽  
2018 ◽  
Vol 6 ◽  
Author(s):  
David M. Singer ◽  
Anne J. Jefferson ◽  
Eric L. Traub ◽  
Nicolas Perdrial
Keyword(s):  
Acid Mine Drainage ◽  
Water Chemistry ◽  
Pore Water ◽  
Mine Drainage ◽  
Solid Phase ◽  
Acid Mine ◽  
Dynamic Relationship ◽  
Pore Water Chemistry ◽  
Hydraulic Gradients ◽  
Debris Dam

Acid mine drainage (AMD) discharge has severe, long lasting impacts on water quality and stream ecology in affected watersheds due in part to the dynamic relationship between toxic metals (e.g. Al, Mn, and Cu) and Fe(III) oxy-hydroxides. Localized areas of biogeochemical activity that can mediate mineralogical transformation changes and cause metal release are potentially linked to stream geomorphology. This relationship has not been previously considered with respect to potential longitudinal variation within an impacted stream. The current work aims to determine how Fe(III) (oxy)-hydroxide speciation and distribution, and pore water chemistry in an AMD-impacted streambed, are affected by the presence of two geomorphic structures (a debris dam and step-pool sequence) in an Ohio watershed impacted by historical coal mining. In terms of solid phase mineralogy and geochemistry, in both the tributary and main stem, goethite was the dominant Fe-bearing phase throughout the AMD deposit depth in cores taken upstream of the geomorphic structures, whereas poorly-crystalline phases dominated downstream of the structures, despite the presence of Fe in the reducible fraction. The concentrations and distribution of extractable Al, Mn, and Cu were also different upstream versus downstream of each structure. Pore water Fe and Mn concentrations were higher downstream of the structures than upstream. Strong downward hydraulic gradients were present above the debris dam and in step-pool 1, whereas weaker upward hydraulic gradients were present below the debris dam and in step-pool 2. This work highlights that AMD deposit speciation and distribution, and pore water chemistry, are not spatially uniform within stream reaches, potentially as a result of groundwater-stream exchange-facilitated interactions in the presence of AMD-derived materials.

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