Nonstationary Thermodynamic Analysis of a Chosen Critical Detail in a Waterproof Concrete Basement Structure Using an Experimentally Verified Model

2017 ◽  
Vol 738 ◽  
pp. 47-57
Author(s):  
Miroslav Ignacak ◽  
Lydia Matiaskova ◽  
Július Šoltész
Keyword(s):  
Assessment Tool ◽  
Parallel Evolution ◽  
Field Measurements ◽  
Basement Structure ◽  
Concrete Walls ◽  
Concrete Members ◽  
Performance Requirements ◽  
Reliable Design ◽  
Using Data ◽  
Transient Thermal

When concrete structures with specific performance requirements call for cracking to be avoided, a reliable crack assessment of hardening concrete members is a crucial task for the design. Concrete walls cast onto already hardened foundation slabs represent an example of externally restrained members commonly subjected to strains resulting from early-age movements. As a consequence, unacceptable cracks may develop. The key parameter for a reliable design of such members is a correct assessment of the hardening phase with respect to the deformation behavior followed with parallel evolution of stiffness and strength properties.This contribution aims to present a macroscopic numerical thermodynamic model which can be used for solving the transient thermal field of a chosen structural detail subjected to thermal loads during early ages. In connection with stress development control, the model represents a mechanical based crack assessment tool for hardening concrete members. Its applicability is discussed at a model solution of a wall-to-slab connection detail in a waterproof concrete basement structure. The model outcome values are verified using data from experimental field measurements.

scholarly journals Drone-Based Remote Sensing for Research on Wind Erosion in Drylands: Possible Applications

2021 ◽  
Vol 13 (2) ◽  
pp. 283
Author(s):  
Junzhe Zhang ◽  
Wei Guo ◽  
Bo Zhou ◽  
Gregory S. Okin
Keyword(s):  
Remote Sensing ◽  
Wind Erosion ◽  
Field Measurements ◽  
Spatially Explicit ◽  
Surface Model ◽  
High Resolution Imagery ◽  
Soil Elevation ◽  
3D Photogrammetry ◽  
Using Data ◽  
Sample Set

With rapid innovations in drone, camera, and 3D photogrammetry, drone-based remote sensing can accurately and efficiently provide ultra-high resolution imagery and digital surface model (DSM) at a landscape scale. Several studies have been conducted using drone-based remote sensing to quantitatively assess the impacts of wind erosion on the vegetation communities and landforms in drylands. In this study, first, five difficulties in conducting wind erosion research through data collection from fieldwork are summarized: insufficient samples, spatial displacement with auxiliary datasets, missing volumetric information, a unidirectional view, and spatially inexplicit input. Then, five possible applications—to provide a reliable and valid sample set, to mitigate the spatial offset, to monitor soil elevation change, to evaluate the directional property of land cover, and to make spatially explicit input for ecological models—of drone-based remote sensing products are suggested. To sum up, drone-based remote sensing has become a useful method to research wind erosion in drylands, and can solve the issues caused by using data collected from fieldwork. For wind erosion research in drylands, we suggest that a drone-based remote sensing product should be used as a complement to field measurements.

scholarly journals Measurements of sea-ice flexural stiffness by pressure characteristics of flexural-gravity waves

2013 ◽  
Vol 54 (64) ◽  
pp. 51-60 ◽  
Author(s):  
Aleksey Marchenko ◽  
Eugene Morozov ◽  
Sergey Muzylev
Keyword(s):  
Elastic Modulus ◽  
Gravity Waves ◽  
Water Depth ◽  
Water Pressure ◽  
Field Measurements ◽  
Effective Elastic Modulus ◽  
Flexural Stiffness ◽  
Flexural Gravity Waves ◽  
Using Data ◽  
Relative Errors

Abstract A method to estimate the flexural stiffness and effective elastic modulus of floating ice is described and analysed. The method is based on the analysis of water pressure records at two or three locations below the bottom of floating ice when flexural-gravity waves propagate through the ice. The relative errors in the calculations of the ice flexural stiffness and the water depth are analysed. The method is tested using data from field measurements in Tempelfjorden, Svalbard, where flexural-gravity waves were excited by an icefall at the front of the outflow glacier Tunabreen in February 2011.

Analysis of Secular Variations of Geomagnetic Field in Lithuania Based on the Survey in 2016

2017 ◽  
Author(s):  
Arunas Buga ◽  
Simona Einorytė ◽  
Romuald Obuchovski ◽  
Vytautas Puškorius ◽  
Petras Petroškevicius
Keyword(s):  
Geomagnetic Field ◽  
Field Research ◽  
Field Measurements ◽  
Geomagnetic Observatory ◽  
Research Activities ◽  
Secular Variations ◽  
Geomagnetic Data ◽  
The Mean ◽  
Using Data ◽  
Magnetic Field Variations

Lithuania is successfully integrated in the European geomagnetic field research activities. Six secular variation research stations were established in 1999 and precise geomagnetic field measurements were performed there in 1999, 2001, 2004, 2007 and 2016. Obtained diurnal magnetic field variations at measuring station and neighbouring observatories were analysed. All measurements are reduced to the mean of the year using data from geomagnetic observatory of Belsk. Based on the measured data the analysis of geomagnetic field parameter secular changes was performed. Results of the presented research are useful for updating the old geomagnetic data as well as for estimation of accuracy of declination model.

scholarly journals Estimation of sediment production in oil palm expansion areas in the Amazon

2018 ◽  
Vol 22 (5) ◽  
pp. 344-348 ◽  
Author(s):  
Antonio K. L. Silva ◽  
Adriano M. L. de Sousa ◽  
Joyse T. S. dos Santos ◽  
João M. Villela ◽  
Lucieta G. Martorano ◽  
...  
Keyword(s):  
Oil Palm ◽  
Assessment Tool ◽  
Elaeis Guineensis ◽  
Swat Model ◽  
National Level ◽  
Sediment Production ◽  
Secondary Vegetation ◽  
Using Data ◽  
Water Assessment ◽  
A Current

ABSTRACT Currently, an activity that has become strategic at a national level is the cultivation of oil palm (Elaeis guineensis) in the northeast region of the Pará State, in eastern Brazilian Amazon. However, the impacts of this crop expansion on the hydro-sedimentological cycle are still unknown. Therefore, this study estimated the impacts of oil palm crop expansion on sediment production in a sub-basin under consolidated use of this crop. The Soil and Water Assessment Tool (SWAT) model was applied in the Mariquita sub-basin, calibrated by the flow regionalization technique, using data measured in the field with a current meter. Simulation results indicated an increase in sediment production between the years 2008 and 2013, which can be attributed to the large reduction of areas of secondary vegetation that were replaced by pasture, oil palm and general agriculture. Oil palm areas had a lower average monthly sediment yield in the rainiest period in all simulated years, compared with areas of general agriculture and pasture.

Differential Effect of Recurrent Concussions on Symptom Clusters in Sport Concussion Assessment Tool

2019 ◽  
Vol 28 (7) ◽  
pp. 735-739
Author(s):  
Jian Chen ◽  
Bruce Oddson ◽  
Heather C. Gilbert
Keyword(s):  
Assessment Tool ◽  
Cross Sectional Study ◽  
Physical Symptoms ◽  
Symptom Clusters ◽  
Cross Sectional ◽  
Sport Concussion ◽  
Comprehensive Survey ◽  
Using Data ◽  
Composite Scores ◽  
The Impact

Context: Symptom checklist in Sport Concussion Assessment Tool has been widely used in preseason assessment and in concussion diagnosis, but the impact of prior concussions on the graded symptoms after a new concussion has not been evaluated. Objective: This study was undertaken to examine reported symptoms associated with recurrent concussions using data of a comprehensive survey among athletes. Design: Retrospective survey and cross-sectional study. Setting: College athletes. Participants: Student athletes who sustained one or more concussions. Main Outcome Measures: Concussion history and graded symptoms of the most recent concussion at time of the survey were surveyed. The impact of prior concussions was examined over symptoms and aggregated symptoms. Results: Multiple concussions were associated with greater reporting of individual symptoms related to emotion and physical symptoms of sensitivity to light and noise: more emotional (z = 2.3, P = .02); sadness (z = 2.4, P = .02); nervousness (z = 2.4, P = .02); irritability (z = 3.6, P = .01); sensitivity to light (z = 2.6, P = .01); and sensitivity to noise (z = 2.4, P = .04). The composite scores of emotional symptom and sensitivity symptom clusters were significantly higher: t = 2.68 (P < .01) and t = 3.35 (P < .01), respectively. Conclusions: The significant rises in emotional and sensitivity symptoms may be an important additive effect of concussive injury. Closer attention should be given to these symptom clusters when evaluating concussion injury and recovery.

scholarly journals Water Temperature Measurements in Turbulent Streams During Periods of Frazil-Ice Formation

1983 ◽  
Vol 4 ◽  
pp. 209-215 ◽  
Author(s):  
T. E. Osterkamp ◽  
R. E. Gilfilian ◽  
J. P. Gosink ◽  
C. S. Benson
Keyword(s):  
Water Temperature ◽  
Field Measurements ◽  
Equilibrium Temperature ◽  
Surface Heat ◽  
Heat Losses ◽  
Cooling Rates ◽  
Cooling Period ◽  
Frazil Ice ◽  
Ice Production ◽  
Transient Thermal

Field measurements of water temperatures in two turbulent streams in interior Alaska have been made during periods of frazil-ice production. The measured equilibrium temperature of the water Te-0.005°C agrees with the value calculated from the electrical conductivity of the water. Average cooling rates of the streams during the summer-to-fall stream cooling period were on the order of several tenths of a degree per day with average surface heat losses of -5 to -18 W m−2. Just prior to a frazil-ice event, the water-cooling rates were -1 to -3 mK min−1with surface heat losses of -47 to -140 M m−2Supercooling at the water surface of a stream prior to and during frazil-ice production does not exceed 0.2°C as shown by measurements of air-water temperature profiles and by radiometer measurements. Mater supercooling at the time of frazil-ice nucleation was &lt;10 mK. These measurements show that frazil-ice nuclei in streams must be other ice particles, cold organic materials, cold soil particles, or a combination of these, that may be introduced into the stream by mass exchange processes at the air-water interface.The maximum observed supercooling was ΔTm40 mK. Two measured values for the residual supercooling were 3 and 9 mK. Frazil growth rates calculated from the observed values of supercooling show that, unless the period of residual supercooling is very long, most of the frazil-ice production during one night of supercooling occurred in the transient thermal period from the time of nucleation to the time that the water became residually supercooled.

Empirical Procedures for Long-Term Prediction of Fatigue Damage for an Instrumented Marine Riser

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
C. Shi ◽  
L. Manuel ◽  
M. A. Tognarelli
Keyword(s):  
Fatigue Damage ◽  
Field Measurements ◽  
Damage Estimation ◽  
Current Profile ◽  
Short Term ◽  
Response Characteristics ◽  
Damage Rate ◽  
Using Data ◽  
Analytical Approaches

Slender marine risers used in deepwater applications can experience vortex-induced vibration (VIV). It is becoming increasingly common for field monitoring campaigns to be undertaken wherein data loggers such as strain sensors and/or accelerometers are installed on such risers to aid in VIV-related fatigue damage estimation. Such damage estimation relies on the application of empirical procedures that make use of the collected data. This type of damage estimation can be undertaken for different current profiles encountered. The empirical techniques employed make direct use of the measurements and key components in the analyszes (such as participating riser modes selected for use in damage estimation) are intrinsically dependent on the actual current profiles. Fatigue damage predicted in this manner is in contrast to analytical approaches that rely on simplifying assumptions on both the flow conditions and the response characteristics. Empirical fatigue damage estimates conditional on current profile type can account explicitly even for complex response characteristics, participating riser modes, etc. With significant amounts of data, it is possible to establish “short-term” fatigue damage rate distributions conditional on current type. If the relative frequency of different current types is known from metocean studies, the short-term fatigue distributions can be combined with the current distributions to yield integrated “long-term” fatigue damage rate distributions. Such a study is carried out using data from the Norwegian Deepwater Programme (NDP) model riser subject to several sheared and uniform current profiles and with assumed probabilities for different current conditions. From this study, we seek to demonstrate the effectiveness of empirical techniques utilized in combination with field measurements to predict the long-term fatigue damage and the fatigue failure probability.

Field measurements for early-age strains in concrete walls

1990 ◽  
Vol 42 (153) ◽  
pp. 203-212 ◽  
Author(s):  
M. Anson ◽  
P. M. Rowilson
Keyword(s):  
Field Measurements ◽  
Early Age ◽  
Concrete Walls

Study on Hydrological Simulation of Jin River Based on SWAT-X Model

2011 ◽  
Vol 84-85 ◽  
pp. 238-243
Author(s):  
Yu Jie Fang ◽  
Wen Bin Zhou ◽  
Ding Gui Luo
Keyword(s):  
River Basin ◽  
Assessment Tool ◽  
Swat Model ◽  
Model Parameters ◽  
Parameter Sensitivity Analysis ◽  
Hydrological Simulation ◽  
Resources Management ◽  
Using Data ◽  
Sensitive Parameters ◽  
Water Assessment

Hydrological simulation is the basis of water resources management and utilization. In this study, Soil and Water Assessment Tool (SWAT) model was applied to Jin River Basin for hydrological simulation on ArcView3.3 platform. The basic database of Jin river Basin was built using ArcGis9.2. Based on the LH-OAT parameter sensitivity analysis, the sensitive parameters of runoff were identified, including CN2, Gwqmn, rchrg_dp, ESCO, sol_z, SLOPE, SOL_AWC, sol_k, Gwrevap, and then model parameters related to runoff were calibrated and validated using data observed in weifang, yifeng, shanggao and gaoan hydrological stations during 2001-2008. The simulation showed that the simulated values were reasonably comparable to the observed data (Re<20%, R2 >0.7 and Nash-suttcliffe > 0.7), suggesting the validity of SWAT model in Jin River Basin.

Semi Empirical Equation for Peak Shears Strength of Rectangular Reinforced Concrete Walls with Aspect Ratio Less or Equal to One

2014 ◽  
Vol 578-579 ◽  
pp. 974-978 ◽  
Author(s):  
Ali Kezmane ◽  
Said Boukais ◽  
Mohand Hamizi
Keyword(s):  
Reinforced Concrete ◽  
Aspect Ratio ◽  
Empirical Equation ◽  
Rectangular Cross Section ◽  
Shear Wall ◽  
Ultimate Shear Strength ◽  
Concrete Walls ◽  
Reinforced Concrete Walls ◽  
Using Data ◽  
Semi Empirical

This paper presents an analytical study on the behavior of reinforced concrete walls with rectangular cross section and aspect ratio less or equal to one. Several experiments on such walls have been selected to be studied. Database from various experiments were collected and nominal shear wall strengths have been calculated using formulas, such as those of the ACI (American), NZS (New Zealand), and Wood and Barda equations. Subsequently, nominal shear wall strengths from the formulas were compared withthe peak shear wall strengths from the database. These formulas vary substantially in functional form and do not account for all variables that affect the response of walls. There is substantial scatter in the predicted values of ultimate shear strength. A new semi empirical equation is developed using data from tests of 126 walls with the objective of improving the prediction of peak strength of walls with the most possible accurate.

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