Laboratory Measurements to Image Endobenthos and Bioturbation with a High-Frequency 3D Seismic Lander

The presented 3D seismic system operates three transducers (130 kHz) from a stationary lander and allows non-destructive imaging of small-scale objects within the top decimeters of silty sediments, covering a surface area of 0.2 m2. In laboratory experiments, samples such as shells, stones, and gummy worms of varied sizes (down to approx. 1 cm diameter) could be located in the 3D seismic cube to a depth of more than 20 cm and differentiated by a reflected amplitude intensity and spatial orientation. In addition, simulated bioturbation structures could be imaged. In a practical application, the system allows to determine the abundance of endobenthos and its dynamic in muddy deposits in-situ and thus identify the intensity of local bioturbation.

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Weathering conditions of Buddhist caves dug in soft rocks and conservation attempting from the deterioration

10.5194/egusphere-egu21-13752 ◽

2021 ◽

Author(s):

Chiaki Oguchi ◽

Momoko Ogawa ◽

Kaisei Sakane ◽

Yasuhiko Tamura

Keyword(s):

Environmental Monitoring ◽

Layer Structure ◽

Physical And Mechanical Properties ◽

Small Scale ◽

Central Japan ◽

Soft Rocks ◽

Geologic Materials ◽

Temperature And Humidity ◽

Non Destructive

The Taya Cave, a sacred Buddhist cave, locates in the precincts of Josenji Temple in Yokohama City, central Japan. The geologic materials of the hills surrounding the cave are soft rocks composed of early Quaternary sedimentary rocks. The cave has a complex three-layer structure with a total length of 570 m. The excavation of the cave is estimated to start in the Kamakura era around A.D. 1200. Since then, the cave became a training place for Buddhists until around 19 C. There are many Buddhist reliefs on the walls and ceiling inside the cave. Because the bedrock is extremely weak, the rocks easily break when they get wet again after drying, namely prone to slaking. Thus, weathering and deterioration have progressed in various parts of the cave. Many valuable Buddhist reliefs have damaged by exfoliation. The walls at several points in the cave have also collapsed on a small scale. Therefore, it is necessary to investigate such deteriorated parts in the cave by simple non-destructive tests of physical and mechanical properties by using Silver Schmidt hammer and ultrasonic velocity test. These measurements clarified the vulnerable points even in the main worship route of the cave. In October 2018, a stainless-steel door installed at the cave entrance to save from deterioration due to slaking. The effect of the door was verified as well by monitoring the environmental conditions inside the cave. Environmental monitoring results revealed that the temperature and humidity near the entrance changed most drastically in this cave. Although the door was closed only at night, the range of maximum and minimum values &#8203;&#8203;of temperature and humidity near the entrance became smaller after installation than before. Non-destructive measurements and in situ environmental monitoring are a useful way to assess weathering without damaging geoarchaeological sites.&#160;

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Laboratory Evaluation and Construction of Fully Recycled Low-Temperature Asphalt for Low-Volume Roads

Advances in Materials Science and Engineering ◽

10.1155/2020/4904056 ◽

2020 ◽

Vol 2020 ◽

pp. 1-12

Author(s):

Christiane Raab ◽

Manfred N. Partl

Keyword(s):

Ambient Temperature ◽

Laboratory Experiments ◽

Traffic Simulation ◽

Traffic Load ◽

Laboratory Evaluation ◽

Small Scale ◽

Medium Scale ◽

Low Volume Roads ◽

Low Volume

Growing economy and increasing pollution evoke the need for more environmentally friendly road construction techniques and the saving of natural resources. In this context, cold recycling plays an important role since, on the one hand, it allows to reduce CO2 emissions drastically and, on the other hand, it offers a variety of opportunities for high percentages of recycling. Inspired by experience in Sweden, the international project “Optimal Recycling of Reclaimed Asphalts for low-traffic Pavement” (ORRAP) for low-volume roads in the Upper Rhine region aims to develop and establish a new strategy for 100% reclaimed asphalt pavement (RAP) at ambient temperature (20°C) without adding virgin bituminous binders or rejuvenators. The still ongoing research project involves laboratory experiments as well as in situ test sections. The link between small-scale laboratory experiments and in situ testing is provided by medium-scale traffic simulation in the laboratory. This paper describes results from medium-scale compaction in the laboratory using different methods as well as traffic simulation with a medium-scale mobile traffic load simulator. The results show that compaction in the laboratory at ambient temperature (20°) is very difficult to achieve. Nevertheless, it was found that compaction at a temperature of 60°C appears possible and provides promising results regarding stability and rutting enabling the in situ construction. The in situ pavement construction at ambient temperature on a low-volume road in Switzerland resulted in a visibly well-compacted and stable base course which was covered by a hot mix asphalt surface course the day after. The test section will be monitored closely over the next 12 months.

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On the Susceptibility of Cold Tropical Cirrus to Ice Nuclei Abundance

Journal of the Atmospheric Sciences ◽

10.1175/jas-d-15-0274.1 ◽

2016 ◽

Vol 73 (6) ◽

pp. 2445-2464 ◽

Cited By ~ 17

Author(s):

Eric J. Jensen ◽

Rei Ueyama ◽

Leonhard Pfister ◽

Thaopaul V. Bui ◽

R. Paul Lawson ◽

...

Keyword(s):

High Frequency ◽

Regional Distribution ◽

Ice Nucleation ◽

Small Scale ◽

Height Distribution ◽

Microphysical Properties ◽

Ice Nuclei ◽

High Frequency Waves ◽

The Impact

Abstract Numerical simulations of cirrus formation in the tropical tropopause layer (TTL) during boreal wintertime are used to evaluate the impact of heterogeneous ice nuclei (IN) abundance on cold cloud microphysical properties and occurrence frequencies. The cirrus model includes homogeneous and heterogeneous ice nucleation, deposition growth/sublimation, and sedimentation. Reanalysis temperature and wind fields with high-frequency waves superimposed are used to force the simulations. The model results are constrained by comparison with in situ and satellite observations of TTL cirrus and relative humidity. Temperature variability driven by high-frequency waves has a dominant influence on TTL cirrus microphysical properties and occurrence frequencies, and inclusion of these waves is required to produce agreement between the simulated and observed abundance of TTL cirrus. With homogeneous freezing only and small-scale gravity waves included in the temperature curtains, the model produces excessive ice concentrations compared with in situ observations. Inclusion of relatively numerous heterogeneous ice nuclei (NIN ≥ 100 L−1) in the simulations improves the agreement with observed ice concentrations. However, when IN contribute significantly to TTL cirrus ice nucleation, the occurrence frequency of large supersaturations with respect to ice is less than indicated by in situ measurements. The model results suggest that the sensitivity of TTL cirrus extinction and ice water content statistics to heterogeneous ice nuclei abundance is relatively weak. The simulated occurrence frequencies of TTL cirrus are quite insensitive to ice nuclei abundance, both in terms of cloud frequency height distribution and regional distribution throughout the tropics.

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Wear-level-monitoring on electrical conductors with high-frequency alternating currents

Frequenz ◽

10.1515/freq-2020-0136 ◽

2020 ◽

Vol 0 (0) ◽

Author(s):

Philipp Lenz ◽

Armin Wittmann ◽

Georg Fischer

Keyword(s):

High Frequency ◽

Alternating Current ◽

The State ◽

In Situ Monitoring ◽

Mechanical Wear ◽

Methodical Approach ◽

Electrical Conductors ◽

Non Destructive ◽

Level Monitoring

AbstractIn this paper, a methodical approach for the in-situ monitoring of the mechanical wear of electrical conductors is presented. The state of life can be assessed by means of the characteristic attenuation of an applied high-frequency alternating current. The advantages of this approach include its non-destructive nature and the applicability to installed and otherwise inaccessible conductors.

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Effects of magnetite on high-frequency ground-penetrating radar

Geophysics ◽

10.1190/geo2012-0266.1 ◽

2013 ◽

Vol 78 (5) ◽

pp. H1-H11 ◽

Cited By ~ 12

Author(s):

Remke L. Van Dam ◽

Jan M. H. Hendrickx ◽

Nigel J. Cassidy ◽

Ryan E. North ◽

Mine Dogan ◽

...

Keyword(s):

Ground Penetrating Radar ◽

High Frequency ◽

Laboratory Experiments ◽

Parent Material ◽

Electromagnetic Properties ◽

Small Scale ◽

Shallow Subsurface ◽

Propagation Behavior ◽

Ground Penetrating ◽

Reflection Characteristics

Large concentrations of magnetite in sedimentary deposits and soils with igneous parent material have been reported to affect geophysical sensor performance. We have undertaken the first systematic experimental effort to understand the effects of magnetite for ground-penetrating radar (GPR) characterization of the shallow subsurface. Laboratory experiments were conducted to study how homogeneous magnetite-sand mixtures and magnetite concentrated in layers affect the propagation behavior (velocity, attenuation) of high-frequency GPR waves and the reflection characteristics of a buried target. Important observations were that magnetite had a strong effect on signal velocity and reflection, at magnitudes comparable to what has been observed in small-scale laboratory experiments that measured electromagnetic properties of magnetite-silica mixtures. Magnetite also altered signal attenuation and affected the reflection characteristics of buried targets. Our results indicated important implications for several fields, including land mine detection, Martian exploration, engineering, and moisture mapping using satellite remote sensing and radiometers.

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In Situ Non-Destructive Temporal Measurements of the Rhizosphere Microbiome ‘Hot-Spots’ Using Metaproteomics

Agronomy ◽

10.3390/agronomy11112248 ◽

2021 ◽

Vol 11 (11) ◽

pp. 2248

Author(s):

Richard Allen White ◽

Joshua Rosnow ◽

Paul D. Piehowski ◽

Colin J. Brislawn ◽

James J. Moran

Keyword(s):

Spatial Organization ◽

Global Scale ◽

Small Scale ◽

Microbial Composition ◽

Earth’S Climate ◽

And Function ◽

Subsurface Injection ◽

Non Destructive ◽

Microbial Hotspots

Rhizosphere arguably embodies the most diverse microbial ecosystem on the planet, yet it is largely a functional ‘black box’ of belowground plant-microbiome interactions. The rhizosphere is the primary site of entry for subsurface injection of fixed carbon (C) into soil with impacts on local to global scale C biogeochemistry and ultimately Earth’s climate. While spatial organization of rhizosphere is central to its function, small scale and steep microbial and geochemical gradients within this dynamic region make it easily disrupted by sampling. The significant challenge presented by sampling blocks elucidation of discreet functions, drivers, and interactions within rhizosphere ecosystems. Here, we describe a non-destructive sampling method linked to metaproteomic analysis in order to measure temporal shifts in the microbial composition and function of rhizosphere. A robust, non-destructive method of sampling microbial hotspots within rhizosphere provides an unperturbed window into the elusive functional interactome of this system over time and space.

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Response of the North Atlantic circulation to the small-scale surface wind perturbations

10.5194/egusphere-egu2020-272 ◽

2020 ◽

Author(s):

Shenjie Zhou ◽

Xiaoming Zhai ◽

Ian Renfrew

Keyword(s):

Ocean Circulation ◽

High Frequency ◽

General Circulation ◽

Large Scale ◽

Sea Surface ◽

Small Scale ◽

Local Response ◽

High Frequencies ◽

Wind Variability

High-frequency and small-scale processes in the atmosphere have an important influence on the evolution of the underlying ocean. They can not only introduce variability to the coupled systems but also have long-term ramification effects on the sea surface temperature, thermocline structure and large-scale ocean general circulation via nonlinear interactions.Comparisons between the newly-released ECMWF fifth-generation global climate reanalyses (ERA5) wind product and satellite/in-situ observations show that the latest reanalyses winds still considerably underestimate wind variability at high-frequencies and small-scales. A novel approach, Cellular Automata (CA), is used here to stochastically perturb the ERA5 wind field. CA, originally introduced into the weather forecast model to mimic the near-grid-scale variability associated with convective cloud clustering, generates spatially and temporally coherent perturbation patterns. Results show that the CA-perturbed ERA5 wind field enjoys an improved wavenumber spectrum, especially over high wavenumber bands (scales <400 km), when compared to the QuikSCAT measurements. In addition, including CA patterns also brings the level of wind variability at high-frequencies (>1 cpd) closer to in-situ mooring measurements. The local response of the upper ocean properties is investigated by a Multi-Column K-Profile Parameterization (MC_KPP) ocean mixed layer model over Atlantic section. It is found that overall the sea surface temperature (SST) decreases and oceanic boundary layer (OBL) deepens to respond to the enhanced surface turbulent heat loss and shear instability generated at the base of surface OBL caused by the small-scale wind perturbations. In particular, SST tends to decrease the most over the summer hemisphere by up to 1&#176;C locally and 0.1&#176;C averaging across the basin, in correlation with shallower background OBL and smaller OBL heat capacity.&#160;The ocean states under the forcing of stochastic wind perturbation as expressed by the local response are found rectified by a non-negilible magnitude. We argued that although the missed small-scale and high-frequency wind variability may be represented differently than our approach, our results highlighted the fact that these variabilities should take a singificant part in driving the current generation of coupled climate model. Furhtermore, the temproal and spatial variabilities of the local signals can pose significant influence on the large-scale ocean circulation in terms of their pathways, strengths and variabilities. The dynamical response of the ocean circulation is to be further understood with an eddy-resolving Massachusette Institute of Technology General Circulation Model (MITgcm).

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Overview of radionuclide migration experiments in the HADES Underground Research Facility at Mol (Belgium)

Clay Minerals ◽

10.1180/claymin.2013.048.2.01 ◽

2013 ◽

Vol 48 (2) ◽

pp. 153-166 ◽

Cited By ~ 9

Author(s):

M. Aertsens ◽

N. Maes ◽

L. Van Ravestyn ◽

S. Brassinnes

Keyword(s):

Diffusion Coefficients ◽

Large Scale ◽

Laboratory Experiments ◽

Small Scale ◽

Transport Parameters ◽

Research Facility ◽

Apparent Diffusion Coefficients ◽

Apparent Diffusion ◽

Clay Formation

AbstractIn situ migration experiments using different radiotracers have been performed in the HADES Underground Research Facility (URF), built at a depth of 225 m in the Boom Clay formation below the SCK–CEN nuclear site at Mol (Belgium). Small-scale experiments, mimicking laboratory experiments, were carried out with strongly retarded tracers (strontium, caesium, europium, americium and technetium). Contrary to europium, americium and technetium which are subjected to colloid mediated transport, the transport of strontium and caesium can be described by the classic diffusion retardation formalism. For these last two tracers, the transport parameters derived from the in situ experiments can be compared with the laboratory-derived values. For both tracers, the apparent diffusion coefficients measured in the in situ experiments agree well with the laboratory-derived values.In the large-scale experiments (of the order of metres) performed in the URF, non-retarded or slightly retarded tracers (HTO, iodide and H14CO3–) were used. The migration behaviour of these tracers was predicted based on models applied in performance assessment calculations (classic diffusion retardation) using migration parameter values measured in laboratory experiments. These blind predictions of large-scale experiments agree well in general with the experimental measurements. Fitting the experimental in situ data leads to apparent diffusion coefficients close to those determined by the laboratory experiments. The iodide and H14CO3– data were fitted with a simple analytical expression, and the HTO data were additionally fitted numerically with COMSOL multiphysics, leading to about the same optimal values.

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