Collapsible soils are almost found in unsaturated states and involved significant engineering problems. Geotechnical challenges of such soils are represented by the hydro-mechanical behaviour during ...wetting–drying cycles due to the humidity and climate conditions. The main objective of this paper is to investigate the soil–water characteristic curve (SWCC) of unsaturated collapsible soils. In this study, three types of collapsible soils were investigated such as natural soils of sandy gypseous, silty loess, and artificial soil of gypsum–sand mixture. Determination of soil–water characteristic curve represented by wetting and drying paths has been done using a combination of the axis-translation technique (
. pressure plate device) and vapour equilibrium technique (
. salts solution desiccators) to cover a wide range of applied suction. The test results show that the air-entry value for all soils occurs at a very low suction range. At the boundary effect zone, the coarse grain size of the soil mass cannot hold the water molecules in the pore space, even with a low value of imposed suction. Moreover, the amount of hysteresis varied based on the geological formation and homogeneity of the soil fabric. Furthermore, SWCC has been interpreted by insignificant volume change and a slight reduction in void ratio, especially at high applied suction.
Collapsible soils present significant geotechnical and structural engineering challenges worldwide. They can be found in arid or semi-arid regions and are directly affected by the multi-step wetting ...procedure due to the reduction of soil suction. The main objectives of this paper are to investigate the volume change behaviour, collapse mechanism and deformation characteristics under the control of suction and net vertical stress. In this study, three types of collapsible soils were investigated such as natural soils of sandy gypseous, silty loess, and artificial soil of gypsum–sand mixture. A series of constant net stress-suction control (wetting and drying) tests using a combination of axis-translation and vapor equilibrium techniques were deployed to cover a wide range of applied suction. The test results show that large volume change and collapse deformation occur upon a stepwise suction decrease. On the other hand, shrinkage behaviour resulting from increases in imposed suction is observed during the drying path. The collapse deformation depends on the stress path and is a function of net normal stress, suction, dry density, and degree of saturation. The water content and the degree of saturation dramatically increase as the applied suction decreases from the initial high to zero values at the drying path.
We present optical, UV, and X-ray monitoring of the short orbital period black hole X-ray binary candidate Swift J1753.5-0127, focusing on the final stages of its 12 yr long outburst that started in ...2005. From 2016 September onward, the source started to fade, and within 3 months, the optical flux almost reached the quiescent level. Soon after that, using a new proposed rebrightening classification method, we recorded a mini-outburst and a reflare in the optical light curves, peaking in 2017 February (V ∼ 17.0) and May (V ∼ 17.9), respectively. Remarkably, the mini-outburst has a peak flux consistent with the extrapolation of the slow decay before the fading phase preceding it. The following reflare was fainter and shorter. We found from optical colors that the temperature of the outer disk was ∼11,000 K when the source started to fade rapidly. According to the disk instability model, this is close to the critical temperature when a cooling wave is expected to form in the disk, shutting down the outburst. The optical color could be a useful tool to predict decay rates in some X-ray transients. We notice that all X-ray binaries that show mini-outbursts following a main outburst are short orbital period systems (<7 hr). In analogy with another class of short-period binaries showing similar mini-outbursts, the cataclysmic variables of the RZ LMi type, we suggest that mini-outbursts could occur if there is a hot inner disk at the end of the outburst decay.
In this paper, we derive a new formulation for an optimal investment allocation in N-regional economic model using quantum calculus analogue. This model is described as an optimal control model and ...formulated in both primal and dual models using quantum calculus formulation. This formulation is an extension of regional economic models. Also, the new formulation provides an exact optimal investment allocation. In addition, the classical regional economic model is obtained by choosing q=1. Furthermore, we formulate the primal and the dual regional economic models in quantum calculus. Moreover, we present a new version of the duality theorems for quantum calculus case. Finally, example is provided and solved using MATLAB. in order to show the given new results.
The quest for fetching an excellent visible light driven photocatalyst is rapidly growing. In this research work, a simple, facile and cost-effective sol–gel method has been described to fabricate ...(1, 2, 3 and 4 At%) cadmium (Cd)-doped ZnO nanoparticles. Effect of various concentration of Cd on structural, optical and morphological properties of ZnO has been intensively investigated using characterization techniques such as SEM, XRD, EDX, PL, BET and UV–VIS. Photocatalytic activity of prepared nanomaterials has been evaluated for the degradation of methylene blue (MB) and rhodamine-B (RhB) dye in the presence of visible light. Quite interestingly, the best degradation efficiency of 91% for MB and 89% for RhB was exhibited by 3% Cd-doped ZnO sample which attributes to the lowering of bandgap energy due to incorporation of dopant element. Increasing the doping concentration beyond this level has detrimental effects in dye degradation owing to the Burstein-Moss effect. Additionally, optimization of various parameters such as pH, dye concentration and catalyst loading were thoroughly investigated. RF module of COMSOL Multiphysics 5.3a has been used to corelate the theoretical results with experimental findings.
The direct-current (DC) motor has been widely utilized in many industrial applications, such as a multi-motor system, due to its excellent speed control features regardless of its greater maintenance ...costs. A synchronous regulator is utilized to verify the response of the speed control. The motor speed can be improved utilizing artificial intelligence techniques, for example fuzzy neural networks (FNNs). These networks can be learned and predicted, and they are useful when dealing with nonlinear systems or when severe turbulence occurs. This work aims to design an FNN based on a model reference controller for separately excited DC motor drive systems, which will be applied in a multi-machine system with two DC motors. The MATLAB/Simulink software package has been used to implement the FNMR and investigate the performance of the multi-DC motor. moreover, the online training based on the backpropagation algorithm has been utilized. The obtained results were good for improving the speed response, synchronizing the motors, and applying load during the work of the motors compared to the traditional PI control method. Finally, the multi-motor system that was controlled by the proposed method has been improved where its speed was not affected by the disturbance.
Foramina transversaria are bilateral landmarks of human cervical vertebrae. Morphometric analysis of foramina transversaria is valuable in both clinical and academic fields. This study aims to build ...a novel normative database of the dimensions of foramina transversaria in Jordanian population and to correlate these data with gender and age. For this purpose, axial computer tomographic images of cervical vertebrae of 329 normal individuals were obtained from the Radiology Department at King Abdulla University Hospital. Cases were subdivided into adolescence, youth, and adulthood groups for both genders. Antero-posterior and transverse diameters were measured bilaterally at all cervical vertebral levels. Statistical analysis of measured dimensions was performed using Statistical Package of Social Sciences software. The results showed that the overall mean antero-posterior diameter of foramina transversaria was 6.09 ± 0.60mms and 5.94 ± 0.62mms on the left and on the right sides, respectively. The corresponding mean transverse diameter measured 4.76 ± 0.51mms and 4.62 ± 0.52mms on the left and the right sides, respectively. Foramina transversaria were significantly larger in males compared to females (
p
= 0.00). Age-related differences were statistically significant for both antero-posterior and transverse diameters in favor of adult age-group, irrespective of vertebral level. The relevance of these findings is discussed.
Abstract
Collapsible soils are problematic soils that have substantial strength while dry but lose strength when wet, resulting in excessive settlements. Soil collapse occurs when increasing moisture ...weakens chemical or physical connections between soil particles, allowing the soil structure to collapse. The existence of these soils, often with significant gypsum concentration, created serious challenges for structures and major projects. The primary goal of this study is to conduct a series of model tests subjected to static vertical stress to assess the ability of soil stabilization using geosynthetics material by employing single, double, and triple geotextile layers put at various places. A unique model test configuration was employed for this testing. The gypseous soil used was brought from near Sawa Lake by coordinates (31◦18′42.83″N, 45◦00′49.36″E) in Al-Muthanna Governorate. The gypsum content was more than (37%). It was found that, the ultimate bearing capacity of dry and wet gypseous soil models had been determined by using Two Tangent Intersection technique. The results show the Settlement Reduction Factor (SRF) % and the ratio of decreasing the collapse magnitude (Δed )
Neurons in the spinal trigeminal nucleus of a camel were morphologically studied by the Golgi impregnation method. The neurons were classified based on the size and shape of their cell bodies, the ...density of their dendritic trees, and the morphology and distribution of their appendages. At least 12 morphological types of neurons were found in the camel spinal trigeminal nucleus, including the following: stalked, islets, octopus-like, lobulated, boat-like, pyramidal, multipolar, round, oval, and elongated neurons. These neurons exhibited large numbers of various forms of appendages that arise not only from their dendrites but also from their cell bodies. Moreover, neurons with unique large dilatations especially at their dendritic branching points were also reported. The neurons reported in this study displayed an array of different sizes and shapes and featured various forms of appendages arising from cell bodies and dendrites. Such morphologically distinctive neuronal cell types might indicate an evolutionary adaptation to pain and temperature processing pathways at the level of the spinal trigeminal nucleus in camels, which traditionally live in a very harsh climatic environment and are frequently exposed to painful stimuli.
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