Numerical and Experimental Investigation of Thermal Signatures of Buried Landmines in Dry Soil

2005 ◽  
Author(s):  
F. Moukalled ◽  
N. Ghaddar ◽  
H. Kabbani ◽  
N. Khaled ◽  
Z. Fawaz
Keyword(s):  
Experimental Investigation ◽  
Numerical Data ◽  
Soil Surface ◽  
Radiant Heat ◽  
Balance Model ◽  
Transient Temperature ◽  
Numerical Predictions ◽  
Dry Soil ◽  
The Difference ◽  
Thermal Signature

This paper reports a numerical and experimental investigation conducted to study the surface thermal signature of buried landmines. Numerical predictions are obtained by solving an unsteady three-dimensional energy balance model for heat transport in dry soil with a buried mine using the conservative finite-volume method. The model is validated by comparing generated results against published analytical and numerical data in addition to indoor measurements performed on dry soil inside an environmental chamber. The thermal signatures are observed while cooling takes place after exposing the soil surface to a radiant heat flux for a specified period. Transient temperature profiles produced numerically agree well with thermocouple measurements recorded at shallow soil depths and with surface IR images. The difference between predicted and measured surface temperatures is less than 0.4°C and the difference in thermal signature is less than 0.3°C. Sit in. The numerical model is also used to predict perturbations of the expected thermal signatures that are compared to the real (measured) ones from the IR images. The thermographic analysis shows good promise as a method for detecting shallowly buried land mines where not only the temperature difference or contrast images generated by the thermal signatures are matched between the IR images and the simulation images with high accuracy, but also the absolute temperatures for many images generated at discrete time intervals.

Numerical and Experimental Investigation of Thermal Signatures of Buried Landmines in Dry Soil

2005 ◽  
Vol 128 (5) ◽  
pp. 484-494 ◽  
Author(s):  
F. Moukalled ◽  
N. Ghaddar ◽  
H. Kabbani ◽  
N. Khalid ◽  
Z. Fawaz
Keyword(s):  
Experimental Investigation ◽  
Numerical Model ◽  
Measurement Techniques ◽  
Infrared Camera ◽  
Soil Surface ◽  
Radiant Heat ◽  
Transient Temperature ◽  
Numerical Predictions ◽  
Soil Temperatures ◽  
Thermal Signature

This paper reports a numerical and experimental investigation conducted to study the thermal signature of buried landmines on soil surface. A finite-volume-based numerical model was developed to solve the unsteady three-dimensional heat transport equation in dry homogeneous soil with a buried mine. Numerical predictions of soil thermal response were validated by comparison with published analytical and numerical values in addition to data obtained experimentally. Experiments were performed inside an environmental chamber and soil temperatures were measured during cooling, using two measurement techniques, after exposing the soil surface to a radiant heat flux for a specified period. In the first technique, the temporal variation of the surface and internal soil temperatures were recorded using thermocouples. In the second technique, the soil surface temperature was measured using an infrared camera that revealed the thermal signature of the mine. The transient temperature profiles generated numerically agreed with measurements, and the difference between predicted and measured values was less than 0.3°C at both the soil surface and in depth. The accurate matching of numerical and IR images at the surfaces was found to strongly depend on the use of a smaller soil thermal conductivity at the surface than at greater depths. The numerical model was used to predict the dependence of the peak thermal contrast on time, depth, and heating period. The thermographic analysis, when combined with numerical predictions, holds promise as a method for detecting shallowly buried land mines.

Numerical Predictions on the Soil Thermal Effect Under Surface Fire Conditions

1997 ◽  
Vol 7 (1) ◽  
pp. 51 ◽  
Author(s):  
LA Oliveira ◽  
DX Viegas ◽  
AM Raimundo
Keyword(s):  
Temperature Distribution ◽  
Flame Front ◽  
Radiation Effects ◽  
Control Volume ◽  
Ground Surface ◽  
Soil Surface ◽  
Heat Transfer Process ◽  
Maximum Temperature ◽  
Transient Temperature ◽  
Numerical Predictions

A control volume numerical method is used to predict the temperature distribution inside a soil extent, the surface of which has been swept by a two-dimensional flame front with pre-defined velocity and temperature distributions. Natural and forced convection, as well as radiation effects are included in the specification of the soil surface thermal boundary condition. The flame residence time and maximum temperature are identified as two major parameters to characterize the flame front. As expected, the heat penetration depth is confined to the near vicinity of the soil surface. Moreover, horizontal heat conduction throughout the soil has not always a significant effect on its global, transient temperature distribution. The influence of wind velocity and of soil thermal diffusivity upon its temperature distribution are analysed. Radiation is the dominant contribution in the whole heat transfer process between flame and ground surface.

scholarly journals Effect of tillage, slope, and rainfall on soil surface microtopography quantified by geostatistical and fractal indices during sheet erosion

2020 ◽  
Vol 12 (1) ◽  
pp. 232-241
Author(s):  
Na Ta ◽  
Chutian Zhang ◽  
Hongru Ding ◽  
Qingfeng Zhang
Keyword(s):  
Surface Roughness ◽  
Fractal Dimension ◽  
Soil Surface ◽  
Rainfall Events ◽  
Tillage Practices ◽  
Surface Microtopography ◽  
Artificial Rainfall ◽  
Soil Surface Roughness ◽  
The Difference ◽  
Sheet Erosion

AbstractTillage and slope will influence soil surface roughness that changes during rainfall events. This study tests this effect under controlled conditions quantified by geostatistical and fractal indices. When four commonly adopted tillage practices, namely, artificial backhoe (AB), artificial digging (AD), contour tillage (CT), and linear slope (CK), were prepared on soil surfaces at 2 × 1 × 0.5 m soil pans at 5°, 10°, or 20° slope gradients, artificial rainfall with an intensity of 60 or 90 mm h−1 was applied to it. Measurements of the difference in elevation points of the surface profiles were taken before rainfall and after rainfall events for sheet erosion. Tillage practices had a relationship with fractal indices that the surface treated with CT exhibited the biggest fractal dimension D value, followed by the surfaces AD, AB, and CK. Surfaces under a stronger rainfall tended to have a greater D value. Tillage treatments affected anisotropy differently and the surface CT had the strongest effect on anisotropy, followed by the surfaces AD, AB, and CK. A steeper surface would have less effect on anisotropy. Since the surface CT had the strongest effect on spatial variability or the weakest spatial autocorrelation, it had the smallest effect on runoff and sediment yield. Therefore, tillage CT could make a better tillage practice of conserving water and soil. Simultaneously, changes in semivariogram and fractal parameters for surface roughness were examined and evaluated. Fractal parameter – crossover length l – is more sensitive than fractal dimension D to rainfall action to describe vertical differences in soil surface roughness evolution.

scholarly journals Calcium Biogeochemical Cycle in a Typical Karst Forest: Evidence from Calcium Isotope Compositions

Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 666
Author(s):  
Guilin Han ◽  
Anton Eisenhauer ◽  
Jie Zeng ◽  
Man Liu
Keyword(s):  
Soil Depth ◽  
Isotope Composition ◽  
Soil Surface ◽  
Natural Soil ◽  
Calcium Isotope ◽  
Karst Forest ◽  
Content Ratio ◽  
The Difference ◽  
Preferential Uptake ◽  
Vital Factor

In order to better constrain calcium cycling in natural soil and in soil used for agriculture, we present the δ44/40Ca values measured in rainwater, groundwater, plants, soil, and bedrock samples from a representative karst forest in SW China. The δ44/40Ca values are found to differ by ≈3.0‰ in the karst forest ecosystem. The Ca isotope compositions and Ca contents of groundwater, rainwater, and bedrock suggest that the Ca of groundwater primarily originates from rainwater and bedrock. The δ44/40Ca values of plants are lower than that of soils, indicating the preferential uptake of light Ca isotopes by plants. The distribution of δ44/40Ca values in the soil profiles (increasing with soil depth) suggests that the recycling of crop-litter abundant with lighter Ca isotope has potential effects on soil Ca isotope composition. The soil Mg/Ca content ratio probably reflects the preferential plant uptake of Ca over Mg and the difference in soil maturity. Light Ca isotopes are more abundant in mature soils than nutrient-depleted soils. The relative abundance in the light Ca isotope (40Ca) is in the following order: farmland > burnt grassland > forests > grassland > shrubland. Our results further indicate that biological fractionation in a soil–plant system is a vital factor for Ca–geochemical transformations in soil surface systems.

scholarly journals Numerical Investigation to the Effect of Suction-Induced Seepage on the Settlement in the Underwater Vacuum Preloading with Prefabricated Vertical Drains

2021 ◽  
Vol 9 (8) ◽  
pp. 797
Author(s):  
Shu Lin ◽  
Dengfeng Fu ◽  
Zefeng Zhou ◽  
Yue Yan ◽  
Shuwang Yan
Keyword(s):  
Practical Implication ◽  
Soil Surface ◽  
Small Strain ◽  
Seepage Flow ◽  
Excess Pore Pressure ◽  
Combined Effects ◽  
Vacuum Preloading ◽  
Prefabricated Vertical Drains ◽  
Vertical Drains ◽  
The Difference

Vacuum preloading combined with prefabricated vertical drains (PVDs) has the potential to improve the soft sediments under water, however, its development is partly limited by the unclear understanding of the mechanism. This paper aims to extend the comprehension of the influential mechanism of overlapping water in the scenario of underwater vacuum preloading with PVDs. The systematic investigations were conducted by small strain finite element drained analyses, with the separated analysis schemes considering suction-induced consolidation, seepage and their combination. The development of settlement in the improved soil region and the evolution of seepage flow from the overlapping water through the non-improved soil region into improved zone are examined in terms of the build-up of excess pore pressure. Based on the results of numerical analyses, a theoretical approach was set out. It was capable to estimate the time-dependent non-uniform settlement along the improved soil surface in response to the combined effects of suction-induced consolidation and seepage. The difference of underwater and onshore vacuum preloading with PVDs is discussed with some practical implication and suggestion provided.

scholarly journals Phenotyping Women Based on Dietary Macronutrients, Physical Activity, and Body Weight Using Machine Learning Tools

Nutrients ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1681 ◽  
Author(s):  
Ramyaa Ramyaa ◽  
Omid Hosseini ◽  
Giri P. Krishnan ◽  
Sridevi Krishnan
Keyword(s):  
Physical Activity ◽  
Machine Learning ◽  
Cluster Analysis ◽  
Body Weight ◽  
Energy Balance ◽  
Numerical Data ◽  
Support Vector ◽  
Learning Tools ◽  
K Nearest Neighbor ◽  
Numerical Predictions

Nutritional phenotyping can help achieve personalized nutrition, and machine learning tools may offer novel means to achieve phenotyping. The primary aim of this study was to use energy balance components, namely input (dietary energy intake and macronutrient composition) and output (physical activity) to predict energy stores (body weight) as a way to evaluate their ability to identify potential phenotypes based on these parameters. From the Women’s Health Initiative Observational Study (WHI OS), carbohydrates, proteins, fats, fibers, sugars, and physical activity variables, namely energy expended from mild, moderate, and vigorous intensity activity, were used to predict current body weight (both as body weight in kilograms and as a body mass index (BMI) category). Several machine learning tools were used for this prediction. Finally, cluster analysis was used to identify putative phenotypes. For the numerical predictions, the support vector machine (SVM), neural network, and k-nearest neighbor (kNN) algorithms performed modestly, with mean approximate errors (MAEs) of 6.70 kg, 6.98 kg, and 6.90 kg, respectively. For categorical prediction, SVM performed the best (54.5% accuracy), followed closely by the bagged tree ensemble and kNN algorithms. K-means cluster analysis improved prediction using numerical data, identified 10 clusters suggestive of phenotypes, with a minimum MAE of ~1.1 kg. A classifier was used to phenotype subjects into the identified clusters, with MAEs <5 kg for 15% of the test set (n = ~2000). This study highlights the challenges, limitations, and successes in using machine learning tools on self-reported data to identify determinants of energy balance.

Numerical Model of Current Speed in Bojong Salawe Beach, Pangandaran West Java Province

2021 ◽  
Vol 2 (1) ◽  
pp. 17-23
Author(s):  
Subiyanto Subiyanto ◽  
Nira na Nirwa ◽  
Yuniarti Yuniarti ◽  
Yudi Nurul Ihsan ◽  
Eddy Afrianto
Keyword(s):  
Numerical Models ◽  
High Tide ◽  
Movement Pattern ◽  
Numerical Data ◽  
Current Speed ◽  
The West ◽  
Instantaneous Speed ◽  
The Difference ◽  
West Monsoon ◽  
Current Movement

The purpose of this study was to determine the hydrodynamic conditions at Bojong Salawe beach. The method used in this research is a quantitative method, where numerical data is collected to support the formation of numerical models such as wind, bathymetry, and tide data. The hydrodynamic model will be made using Mike 21 with the Flow Model FM module to determine the current movement pattern based on the data used. In the west monsoon with a maximum instantaneous speed of 0.04 - 0.08 m/s, while in the east monsoon it moves with a maximum instantaneous speed of 0,4 – 0,44 m/s. The dominant direction of current movement tends to the northeast. The results indicate the current speed during the east monsoon is higher than the west monsoon. The difference in the current speed is also influenced by the tide conditions; higher during high tide and lower during low tide. Monsoons also have a role in the current movements, though the effect is not very significant.

Rewetting Analysis of Hot Moving Surface by Round Water Jet Impingement

2018 ◽  
Author(s):  
Avadhesh Kumar Sharma ◽  
Mayank Modak ◽  
Santosh K. Sahu
Keyword(s):  
Experimental Investigation ◽  
Reynolds Number ◽  
Thermal Imaging ◽  
Transient Temperature ◽  
Axial Distance ◽  
Initial Surface ◽  
Moving Plate ◽  
Thermal Imaging Camera ◽  
Plate Velocity ◽  
Imaging Camera

Impinging jets are commonly utilized in the run-out table (ROT) cooling in the hot rolling process in steel manufacturing industries. The phenomenon of rapid cooling of a sufficiently hot surface is termed as the quenching. The present paper reports the rewetting behavior of 0.15 mm thick hot moving stainless steel foil (SS-304) by circular impinging jet from bottom side through experimental investigation. The transient temperature of the hot foil is recorded by using thermal imaging camera (A655sc, FLIR system). Tests are performed for a varied range of Reynolds number (Re = 2500–10000), nozzle to plate distance (z/d = 6), moving plate velocity (0–40 mm/s) and initial surface temperature 500±10 °C. Transient temperature obtained from thermal imaging camera is used to evaluate rewetting time and rewetting velocity. Based on the experimental investigation correlation has been proposed to predict non-dimensional rewetting velocity as a function of various parameters, namely, Reynolds number, non-dimensional axial distance and moving plate velocity.

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