Dataglove Measurement of Joint Angles in Sign Language Handshapes

In sign language research, we understand little about articulatory factors involved in shaping phonemic boundaries or the amount (and articulatory nature) of acceptable phonetic variation between handshapes. To date, there exists no comprehensive analysis of handshape based on the quantitative measurement of joint angles during sign production. The purpose of our work is to develop a methodology for collecting and visualizing quantitative handshape data in an attempt to better understand how handshapes are produced at a phonetic level. In this pursuit, we seek to quantify the flexion and abduction angles of the finger joints using a commercial data glove (CyberGlove; Immersion Inc.). We present calibration procedures used to convert raw glove signals into joint angles. We then implement those procedures and evaluate their ability to accurately predict joint angle. Finally, we provide examples of how our recording techniques might inform current research questions

Passive temperature tomography experiments to characterize transmissivity and connectivity of preferential flow paths in fractured media

International audienceThe detection of preferential flow paths and the characterization of their hydraulic properties are major challenges in fractured rock hydrology. In this study, we propose to use temperature as a passive tracer to characterize fracture connectivity and hydraulic properties. In particular, we propose a new temperature tomography field method in which borehole temperature profiles are measured under different pumping conditions by changing successively the pumping and observation boreholes. To interpret these temperature- depth profiles, we propose a three step inversion-based framework. We consider first an inverse model that allows for automatic permeable fracture detection from borehole temperature profiles under pumping conditions. Then we apply a borehole-scale flow and temperature model to produce flowmeter profiles by inversion of temperature profiles. This second step uses inversion to characterize the relationship between temperature variations with depth and borehole flow velocities (Klepikova et al., 2011). The third inverse step, which exploits cross-borehole flowmeter tests, is aimed at inferring inter-borehole fracture connectivity and transmissivities. This multi-step inverse framework provides a means of including temperature profiles to image fracture hydraulic properties and connectivity. We test the proposed approach with field data obtained from the Ploemeur (N.W. France) fractured rock aquifer, where the full temperature tomography experiment was carried out between three 100 m depth boreholes 10 m apart. We identified several transmissive fractures and their connectivity which correspond to known fractures and corroborate well with independent information, including available borehole flowmeter tests and geophysical data. Hence, although indirect, temperature tomography appears to be a promising approach for characterizing connectivity patterns and transmissivities of the main flow paths in fractured rock

Heat as a tracer for understanding transport processes in fractured media: Theory and field assessment from multiscale thermal push-pull tracer tests

International audienceThe characterization and modeling of heat transfer in fractured media is particularly challenging as the existence of fractures at multiple scales induces highly localized flow patterns. From a theoretical and numerical analysis of heat transfer in simple conceptual models of fractured media, we show that flow channeling has a significant effect on the scaling of heat recovery in both space and time. The late time tailing of heat recovery under channeled flow is shown to diverge from the TðtÞ / t 21:5 behavior expected for the classical parallel plate model and follow the scaling TðtÞ / 1=tðlog tÞ 2 for a simple channel modeled as a tube. This scaling, which differs significantly from known scalings in mobile-immobile systems, is of purely geometrical origin: late time heat transfer from the matrix to a channel corresponds dimensionally to a radial diffusion process, while heat transfer from the matrix to a plate may be considered as a one-dimensional process. This phenomenon is also manifested on the spatial scaling of heat recovery as flow channeling affects the decay of the thermal breakthrough peak amplitude and the increase of the peak time with scale. These findings are supported by the results of a field experimental campaign performed on the fractured rock site of Ploemeur. The scaling of heat recovery in time and space, measured from thermal breakthrough curves measured through a series of push-pull tests at different scales, shows a clear signature of flow channeling. The whole data set can thus be successfully represented by a multichannel model parametrized by the mean channel density and aperture. These findings, which bring new insights on the effect of flow channeling on heat transfer in fractured rocks, show how heat recovery in geothermal tests may be controlled by fracture geometry. In addition, this highlights the interest of thermal push-pull tests as a complement to solute tracers tests to infer fracture aperture and geometry

Hydrological behavior of a deep sub-vertical fault in crystalline basement and relationships with surrounding reservoirs

International audienceCrystalline-rock aquifers generally yield limited groundwater resources. However, some highly productive aquifers may be encountered, typically near tectonic discontinuities. In this study, we used a multidisciplinary experimental field approach to investigate the hydrogeological behavior of a sub-vertical permeable fault zone identified by lineament mapping. We particularly focused our investigations on the hydrogeological interactions with neighboring reservoirs. The geometry of the permeable domains was identified from geological information and hydraulic test interpretations. The system was characterized under natural conditions and during a 9-week large-scale pumping test. We used a combination of piezometric analysis, flow logs, groundwater dating and tracer tests to describe the interactions between permeable domains and the general hydrodynamical behaviors. A clear vertical compartmentalization and a strong spatial heterogeneity of permeability are highlighted. Under ambient conditions, the vertical permeable fault zone allows discharge of deep groundwater flows within the superficial permeable domain. The estimated flow across the total length of the fault zone ranged from 170 to 200 m3/day. Under pumping conditions, hydrological data and groundwater dating clearly indicated a flow inversion. The fault zone appears to be highly dependent on the surrounding reservoirs which mainly ensure its recharge. Groundwater fluxes were estimated from tracer tests interpretation. This study demonstrates the hydrogeological capacities of a sub-vertical fault aquifer in a crystalline context. By describing the hydrological behavior of a fault zone, this study provides important constrain about groundwater management and protection of such resources

Characterizing fractured rock aquifers using heated Distributed Fiber-Optic Temperature Sensing to determine borehole vertical flow

International audienceIn highly heterogeneous media, fracture network connectivity and hydraulic properties can be estimated using methods such as packer- or cross-borehole pumping-tests. Typically, measurements of hydraulic head or vertical flow in such tests are made either at a single location over time, or at a series of depths by installing a number of packers or raising or lowering a probe. We show how this often encountered monitoring problem, with current solutions sacrificing either one of temporal or spatial information, can be addressed using Distributed Temperature Sensing (DTS). Here, we electrically heat the conductive cladding materials of cables deployed in boreholes to determine the vertical flow profile. We present results from heated fiber optic cables deployed in three boreholes in a fractured rock aquifer at the much studied experimental site near Ploemeur, France, allowing detailed comparisons with alternative methods (e.g. Le Borgne et al., 2007). When submerged in water and electrically heated, the cable very rapidly reaches a steady state temperature (less than 60 seconds). The steady state temperature of the heated cable, measured using the DTS method, is then a function of the velocity of the fluid in the borehole. We find that such cables are sensitive to a wide range of fluid velocities, and thus suitable for measuring both ambient and pumped flow profiles at the Ploemeur site. The cables are then used to monitor the flow profiles during all possible configurations of: ambient flow, cross-borehole- (pumping one borehole, and observing in another), and dipole-tests (pumping one borehole, re-injection in another). Such flow data acquired using DTS may then be used for tomographic flow inversions, for instance using the approach developed by Klepikova et al., (submitted). Using the heated fiber optic method, we are able to observe the flow response during such tests in high spatial detail, and are also able to capture temporal flow dynamics occurring at the start of both the pumping and recovery phase of cross-borehole- and dipole- tests. In addition, the clear advantage of this is that by deploying a single fiber optic cable in multiple boreholes at a site, the flow profiles in all boreholes can be simultaneously measured, allowing many different pumping experiments to be conducted and monitored in a time efficient manner

Potential of heat tracer tests for characterizing fractured media

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Characterization of interactions between sub-surface compartments and a deep sub-vertical aquifer in crystalline basement (St-Brice en Coglès, French Brittany)

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The hydrogeological observatory of Ploemeur (France) : Long-term monitoring and experimentations

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Groundwater sources and geochemical processes in a crystalline fault aquifer

International audienceThe origin of water flowing in faults and fractures at great depth is poorly known in crystalline media.This paper describes a field study designed to characterize the geochemical compartmentalization of adeep aquifer system constituted by a graben structure where a permeable fault zone was identified. Analysesof the major chemical elements, trace elements, dissolved gases and stable water isotopes reveal theorigin of dissolved components for each permeable domain and provide information on various watersources involved during different seasonal regimes. The geochemical response induced by performinga pumping test in the fault-zone is examined, in order to quantify mixing processes and contributionof different permeable domains to the flow. Reactive processes enhanced by the pumped fluxes are alsoidentified and discussed.The fault zone presents different geochemical responses related to changes in hydraulic regime. Theyare interpreted as different water sources related to various permeable structures within the aquifer.During the low water regime, results suggest mixing of recent water with a clear contribution of olderwater of inter-glacial origin (recharge temperature around 7 C), suggesting the involvement of watertrapped in a local low-permeability matrix domain or the contribution of large scale circulation loops.During the high water level period, due to inversion of the hydraulic gradient between the major permeablefault zone and its surrounding domains, modern water predominantly flows down to the deep bedrockand ensures recharge at a local scale within the graben.Pumping in a permeable fault zone induces hydraulic connections with storage-reservoirs. The overlaidregolith domain ensures part of the flow rate for long term pumping (around 20% in the present case).During late-time pumping, orthogonal fluxes coming from the fractured domains surrounding the majorfault zone are dominant. Storage in the connected fracture network within the graben structure mainlyensures the main part of the flow rate (80% in the present case). Reactive processes are induced by mixingof water from different sources and transfer conditions. A specific approach is applied to quantify thereaction rate involved along the pumping time. Autotrophic denitrification coupled with iron mineralsoxidation is highlighted and water rock interaction is clearly enhanced by the flux changes induced bypumping

Use of heat as a groundwater tracer in fractured rock hydrology

International audienceCrystalline rocks aquifers are often difficult to characterize since flows are mainly localized in few fractures. Inparticular, the geometry and the connections of the main flow paths are often only partly constrained with classicalhydraulic tests. Here, we show through few examples how heat can be used to characterize groundwaterflows in fractured rocks at the borehole, inter-borehole and watershed scale. Estimating flows from temperaturemeasurements requires heat advection to be the dominant process of heat transport, but this condition is generallymet in fractured rock at least within the few structures where flow is highly channelized. At the borehole scale,groundwater temperature variations with depth can be used to locate permeable fractures and to estimates boreholeflows. Measurements can be done with classical multi-parameters probes, but also with recent technologies such asFiber Optic Distributed Temperature Sensing (FO-DTS) which allows to measure temperature over long distanceswith an excellent spatial and temporal resolution. In addition, we show how a distributed borehole flowmeter canbe achieved using an armored fiber-optic cable and measuring the difference in temperature between a heatedand unheated cable that is a function of the fluid velocity. At the inter-borehole scale, temperature changes duringcross-borehole hydraulic tests allow to identify the connections and the hydraulic properties of the main flowpaths between boreholes. At the aquifer scale, groundwater temperature may be monitored to record temperaturechanges and estimate groundwater origin. In the example chosen, the main water supply comes from a depth of atleast 300 meters through relatively deep groundwater circulation within a major permeable fault zone. The influenceof groundwater extraction is clearly identified through groundwater temperature monitoring. These examplesillustrate the advantages and limitations of using heat and groundwater temperature measurements for fracturedrock hydrology