Analysis of Object Depth Effects on Accuracy of Dimensional Shape in X and Y Directions Using Single Non-metric Image

In general, to reconstruct the accurate shape of buildings, we need at least one stereomodel (two photographs) for each building. In most cases, however, only a single non-metric photograph is availabl...     

Impact of spatial rainfall resolution on point-source solute transport modelling

Numerical simulations of unsaturated solute transport from point sources were carried out using HYDRUS-1D. Three different soil types cropped with spring wheat were considered at three different locations in Sweden: Malmö, Norrköping and Petisträsk. Two types of rainfall data were used, point-scale raingauge measurements and a gauge-adjusted weather radar product at four spatial resolutions, 2 × 2, 6 × 6, 10 × 10 and 14 × 14 km². The results showed that differences in the mean solute transport depths were small and not significant, with the exception of Petisträsk. Maximum transport depths were in most cases significantly larger using raingauge data compared to radar data. The results showed that using areal-averaged rainfall input will give solute transport estimations close to those using point-measured data. This shows the great potential in using radar-measured rainfall data in small-scale hydrological applications.     

Long-term changes in sea surface temperature(SST) within the southern Levantine Basin

Knowledge of sea surface temperature(SST) behaviour is vital for long-term climate scenarios. This study highlights essential outcomes about the distinguishable and unsurprising warming of the SST along the southern border of the Levantine Basin. The analysis is based on monthly SST data for the period 1948–2018. The southern Levantine Basin has undergone SST increase, during the last 71 years. In this study, a consistent warming trend has been found for the analysed SST data series, with a rate of 0.04°C/a, i.e., 0.4°C/(10 a). From 1975 to 1991 the mean annual SST was 17.1°C, and this increased to be 19.2°C, over the period 2002–2018. Results revealed two opposite trends of variability: a decreasing trend(–0.06°C/a) over the period 1975–1991, and an increasing trend(0.2°C/a) from 2002 to 2018. Over the period 1948–2018, positive mean annual SST anomalies had an average of1.8°C, and negative anomalies had an average of –1.1°C. The lowest SST total increase was found from January to April, with values about 0.03°C, while the highest warming appeared from June to September. The driving mechanisms behind the SST changes need to be more investigated, to understand the future trends and impacts of climate change in the Levantine Basin.     

Effects of Soil Aging on Mechanical and Hydraulic Properties of a Silty Soil

The aging phenomenon, which produces changes in material state over time, is associated with significant modification of mechanical and physical soil properties. This change should be accounted for during geotechnical design. Although soils sometimes improve with aging, the opposite effect is occasionally observed. This paper describes a study performed to investigate the effect of aging on the mechanical behavior and the permeability of a silty soil. Undrained unconsolidated triaxial shear tests and triaxial permeability tests were performed on disturbed and compacted samples. Upon conclusion of these tests, the samples were sealed from air and moisture. The results show an important increase in both the undrained shear strength and the deformation modulus caused by silt rigidification during the aging process. These changes cause an over estimation of laboratory measured shear strength. For instance, the increase in the deformation modulus and undrained cohesion can approach 100 % for an approximate 328 day storage period. Sample permeability was found to decrease with aging. This reduction can be ascribed to several causes including micro-organisms growth, secondary sample consolidation and progressive filling caused by the migration of very fine particles. These phenomena might have negated the expected increase in permeability with aging time reported in the literature.     

Some metal concentrations in the edible parts of Tridacna maxima, Red Sea, Egypt

The concentrations of Ca, some essential (Fe, Zn, Mn, and Cu) and non-essential nutritive elements (Cd, Pb, and Ni) were measured in the edible parts (mantle and adductor muscles) of Tridacna maximx collected from south Quseir City (Red Sea). The general trend of metal contents of the different parts follows the order; Ca > Fe > Zn > Pb > Mn > Cu > Cd > Ni. The tissues before cooking recorded the highest average concentrations of Cu, Pb, Fe, Cd, Mn, and Ni (2.658, 5.250, 34.375, 1.464, 3.207, and 0.886 ppm, respectively) relative to tissues after cooking and the water of cooked tissues (WCT). The total cooked tissues recorded higher average contents of Zn and Ca (17.282 and 1,114.679 ppm) than the uncooked tissues. Calcium recorded the highest concentration in the ECT of adductor and mantle muscles (2,081.126 ± 177.39 and 1,893.326 ± 394.28 ppm). Mantle recorded higher concentrations of Pb, Mn, Ni, and Ca (7.489 ± 4.65, 4.241 ± 1.13, 0.980 ± 0.60, and 1,039.362 ± 177.42 ppm, respectively) than adductor muscle before cooking. Ca concentration levels in the WCT increased after cooking tissues especially in adductor muscles. This may attributed to the liberation of larger amount of calcium in ionic form in water. The clams may have intracellular regulatory mechanisms to keep their concentrations in equilibrium, subsequently; the recorded metal concentrations are in the safe limits for human consuming, where these concentrations did not exceed the clam’s capacity of regulation.     

Aridic crusts and vein mineralisations in the playa Areg el Makrzene, South Tunisia

The playa Areg el Makrzene is situated in the north of the escarpment of the Djebel Rehach in southern Tunisia. It is characterised by more than 70 spring mounds which are bound to faults in the Triassic sandstone, and by (sub-) recent calcareous and iron hydroxide precipitations. The artesian spring water contains high amounts of Na⁺, Ca²⁺, Mg²⁺ and Cl⁻, SO₄²⁻, and HCO₃, shows slightly alkaline character and a temperature of 25 °C. The spring mounds consist of porous travertine (calcite), goethite, gypsum and of Na–Mg evaporites and are up to 10 m high. Few metres away from the springs the amorphous iron hydroxides have altered to badly ordered goethite and ferrihydrite and finally to well ordered goethite. The muddy precipitate has altered to hard crusts (calcrete, ferricrete). The source of the precipitated material is discussed.

The faults in the sandstone are filled with (hydr-)oxides of iron and manganese, e.g. with goethite, hollandite and pyrolusite. The amount of Mn-oxides may reach 60 mass%.     

The advanced spaceborne thermal emission and reflection radiometer (ASTER): Data products for the high spatial resolution imager on NASA’s Terra platform

Landsat 8 Oli, ASTER, and Sentinel 2A satellite images processing was used to map geological formations, lineaments and hydrothermal alteration minerals in the Aouli inlier, as a case study to illustrate the application of digital images processing and Geographic Information System (GIS) in geological mapping and mining prospecting. Principal Component Analysis (PCA) applied to the Landsat images allowed good lithological discrimination and contributed to the updating of available geological maps. The Automatic lineament extraction from Sentinel images revealed the main tectonic structures affecting Aouli inlier. The ratio bands (b5+b7)/b6 and the false color composite (b4/b6, b2/b1, b3/b2) allowed the hydrothermal alteration minerals mapping from Aster images. Combined with available geological data and field observations, the satellite derived data were integrated and analyzed in a GIS software to establish mining prospecting guides. The results showed that the anomaly zones are intimately linked to NNE–SSW and NW–SE oriented faults and to highly fractured areas developing argillic and Fe rich alterations. Verified via field survey, this approach was successfully applied to the Aouli inlier to rapidly target potential areas to be explored in the tactical phase. This provides a model for future prospecting efforts for similar mineral deposits in other areas.