The present research employs new boosting-based ensemble machine learning models i.e., gradient boosting (GB) and adaptive boosting (AdaBoost) to predict the unconfined compressive strength (UCS) of ...geopolymer stabilized clayey soil. The GB and AdaBoost models were developed and validated using 270 clayey soil samples stabilized with geopolymer, with ground-granulated blast-furnace slag and fly ash as source materials and sodium hydroxide solution as alkali activator. The database was randomly divided into training (80%) and testing (20%) sets for model development and validation. Several performance metrics, including coefficient of determination (R
), mean absolute error (MAE), root mean square error (RMSE), and mean squared error (MSE), were utilized to assess the accuracy and reliability of the developed models. The statistical results of this research showed that the GB and AdaBoost are reliable models based on the obtained values of R
(= 0.980, 0.975), MAE (= 0.585, 0.655), RMSE (= 0.969, 1.088), and MSE (= 0.940, 1.185) for the testing dataset, respectively compared to the widely used artificial neural network, random forest, extreme gradient boosting, multivariable regression, and multi-gen genetic programming based models. Furthermore, the sensitivity analysis result shows that ground-granulated blast-furnace slag content was the key parameter affecting the UCS.
Abstract
This research aims to assess geoenvironmental risks and identify the primary deterioration drivers in ancient buildings in Najran City, utilizing various analytical tools to help make ...informed judgments. The samples extruded from historical buildings were examined using field inspection, experimental data, SEM, EDX, and XRD analyses, in addition to lab and field observations and meteorological data. The dissolution of clay minerals and salt crystallization are the key contributors to the degradation and cracking of historical buildings in Najran City, according to lab and field observations. When the daytime high temperature surpasses 44 °C, wind erosion and humidity might cause continuous wetting–drying cycles on the investigated building surfaces. Test results indicated that the average unconfined compressive strength of the extruded earthen wall samples was 2 MPa and the water absorption was within the upper allowed limit (i.e., 15%). A finite element model of a typical earthen historical building was developed using PLAXIS 3D software to assess the behavior and nonlinear response of the silty sand soil layer underlying the building and the earthen historical buildings themselves using a plastic material model. The field observations confirm the results of the simulation, which clearly explained the failure mechanism. The integrated geotechnical and numerical simulations could provide insights for assessing geoenvironmental risks, identify the primary deterioration drivers in ancient buildings, and provide an understanding of material qualities and failure causes not only in the studied area but in other similar regions elsewhere.
The deficiency of high-quality soils in Saudi Arabia’s southern and northern regions, as well as along the Arabian Gulf coasts, is regarded as one of the most common issues with the construction of ...roads. High compressibility, low shear strength, substantial volume change (particularly in Sabkha), and low bearing capacity are the most typical issues with these problematic soils. In this study, finite element simulations were performed using the Plaxis 3D software v20 to simulate the performance and study the critical responses (fatigue, rutting strains, and damage ratio) of an enhanced pavement structure with a geogrid reinforcement resting on the naturally problematic Sabkha subgrade. A normal asphalt concrete layer, a base layer of Sabkha soil stabilized with Foamed Sulfur Asphalt (FSA), and a sand dune subbase layer comprised the pavement structure. For each layer, the model’s input parameters were a mix of laboratory and literature data. The simulation was performed on a pavement structure without reinforcement and on another section enhanced with a geogrid positioned at various locations to determine the ideal placement for lowering the important responses such as fatigue, rutting stresses, and damage ratio. The nonlinear behavior of an FSA–Sabkha base, sand subbase layer, and Sabkha subgrade was simulated using the hardening soil model, whereas the asphaltic concrete layer and geogrid material were simulated using the linear elastic model. The findings of the simulations demonstrated that placing geogrid reinforcement at the top of the subgrade layer resulted in the greatest reduction in horizontal tensile (fatigue) and vertical compressive (rutting) strains, as well as vertical displacement (32.71%, 13.2%, and 14.2%, respectively). In addition, geogrid reinforcement greatly reduced the fatigue damage ratio (33% to 55%), although the reduction in the rutting damage ratio was slightly lower (14% to 30%). The simulation results were validated using a wheel tracking machine and it was clear that there is a reasonable agreement between the results.
The COVID-19 pandemic has not only caused a global health crisis, but it has also had significant environmental and human consequences. During the COVID-19 pandemic, this study focused on emerging ...challenges in managing healthy personal protective materials (HPPM) in Kingdom of Saudi Arabia, using silty sand (SM) soil as an example since it covers large areas in KSA and in the whole world. The main objective of this paper is to find a novel way to minimize pandemic-related waste by using HPPM as waste materials in road construction. For the first time, a series of experiments was conducted on a mixture of different percentages of shredded HPPM (0, 0.5, 1 and 2%) added to the silty sand (SM) soil for road applications, including soil classification according to the USCS, modified compaction, UCS, UPV, and CBR. In addition, a numerical simulation was performed using geotechnical-based software Plaxis 3D to study the performance of the soil-HPPM mix as a subbase layer in the paving structure under heavy traffic loading. The modified compaction test results show that there is an increase in the optimum moisture content with increasing the HPPM contents from 0.5% to 1% and 2%. However, a reduction in the maximum dry density is observed. The values of dry density and water content at 0%, 0.5%, 1% and 2% pf HPPM are 2.045, 1.98, 1.86 and 1.8 g/cm3 and 7.65% 8%, 8.5% and 9.5%, respectively. The soaked CBR values at 0, 0.5, 1 and 2% HPPM are 23, 30, 8, 2% with the maximum value attained with the addition of 0.5% HPPM. The results of UCS were with the same percentages of HPPM 430, 450, 430 and 415 kPa, respectively, with the maximum value attained with 0.5% HPPM addition as well. In contrast, the values of UVP at 0%, 0.5%, 1% and 2% are 978.5, 680.3, 489.4 and 323.6 m/s, respectively, confirming the trends obtained by modified compaction test results. The simulation results confirm this conclusion that the soil-HPPM mix show a superior performance when used as a subbase layer and reduced vertical displacement by a percentage of 11% compared to the normal subbase material. By eliminating HPPM especially facemasks from the landfill lifecycle, incorporating them into high quality construction material production has the potential to deliver significant environmental benefits.
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1Influence of polypropylene (HPPM) fibres on the performance of sandy soil is clearly studied.2The optimum fibres content is obtained as 0.5% volume fraction.3Positive improvement is also noticed in unconfined compressive strength and compaction after adding HPPM fibres.4Fibres play a major role in crack bridging.
This paper presents the utilization of models already derived from results of dynamic triaxial tests performed on marginal soils (marl and sabkha) stabilized with foamed and emulsified sulfur ...asphalt. These stabilized materials are considered to be used as base layers in a pavement structure. Permanent strain relations obtained from dynamic triaxial testing were used in VESYS model to predict rutting performance and magnitude. Predicted rutting performance and magnitude were close to the actual rut depth measured during wheel tracking tests to validate the models. These models developed for rutting prediction were used in VESYS 5 W software to forecast the life or the axle passes needed to attain a rut depth delineating the end of life for a variety of pavement thicknesses, and the subgrade soils to create original pavement thickness design charts. Most of the subgrade soils in Saudi Arabia as well as the coastal areas of the Arabian Gulf are usually marl, sabkha or dune sand soils.
People are forced to use all types of soil, especially bad soils, as infrastructure demands grow. Different procedures must be used to ameliorate these poor soils, which are fragile during building. ...Natural resource depletion and the rising costs of available materials force us to consider alternative supplies. For several years, researchers have investigated the use of by-products from industry and associated approaches to improve the qualities of various soils. Coarse Aggregate Crushing Waste (CACW) is a waste product that results from the primary crushing of aggregates. Massive amounts of CACW are produced in the business, posing serious issues from handling to disposal. As a result, the widespread use of CACW for diverse purposes has been recommended in the civil engineering profession to address these concerns. Because some natural resources, such as gravel, are nonrenewable, it is vital to decrease their consumption and replace them with recycled, cost-effective, and ecologically acceptable alternatives. This research aimed to investigate the possibility of reusing CACW to improve the geotechnical properties of silty sand (SM) soil available in the Najran region. In this research, soil samples were collected from Najran city and subjected to a variety of lab experiments to determine their characterization. Mixes were designed for a parent soil with a range of percentages of CACW with/without 2% cement. The designed mixes were examined through a set of lab tests to obtain the optimum design for use in road construction. The findings of the tests showed that the optimum dosage is 10% CACW with 2% cement, raising the undrained shear strength of silty sand soil by 323%, CBR by 286%, and P-wave by 180%. The durability tests show that soil mixed with 10% CACW and 2% cement fulfills the requirements and stays within the 14% weight loss limit imposed by the Portland Cement Association (PCA). The microscopic investigation results confirmed the outcomes obtained by macro tests. As a result, the carbon footprint values decrease when CAWA is added, making this treatment approach almost carbon neutral. This study clarifies the long-term effects of CACW on improving the geotechnical characteristics of silty sand soil in the Najran Region of the Kingdom of Saudi Arabia and other comparable soils globally.
•Established a link between sedimentary cyclicity and the physico-mechanical properties of limestone and marl rocks.•Quartz has a significant impact on the mechanical characteristics and rock ...strength of the Dam Formation.•outlines the physico-mechanical characteristics of the marl-dominated emergence cycles and the limestone-dominated submergence cycles.•Development of workflow and empirical equations for use in subsurface reservoir modeling.
This study aims to link the cyclicity with the mechanical and physical properties of limestone and marl rocks, using the Dam Formation in eastern Saudi Arabia as a case study. In this work, the Dam Formation sediments from five outcrop sections are investigated using detailed petrography, scanning electron microscope, X-ray diffraction, and petrographic image analysis software tool. Additionally, the physical and mechanical properties have been determined for marl and limestone samples. The study revealed that the emergence cycles result in the deposition of clastic sediments, in contrast to the submergence cycle, which leads to the deposition of carbonates. The dominant pore types, such as intercrystalline, micropores, mouldic, and vuggy, play an important role in the variation of mechanical and physical properties of the Dam Formation carbonate rocks. Secondary porosity produced by the dissolution of carbonate grains has a direct influence on mechanical properties. Physical measurements exhibit that limestone has a porosity of 10.5% and marl has a porosity of 5%. Regarding physical properties prediction, our analysis shows that the emergence cycle commonly increases the chances of a decrease in matrix porosity and an increase in fractures, vugs, and cavern porosity, as well as increasing the permeability of the carbonate in the Dam Formation. A combined analysis of sedimentological and diagenetic features indicates that the clastic or marly sequences have low porosity and high uniaxial compressive strength (UCS); conversely, the limestone rock has high porosity and low UCS values. Quartz has an impact on the mechanical properties of the Dam Formation and is a major control of rock strength in clastic sediments. The UCS in emergence cycles shows moderate to strong strength, and saturation results in a loss of strength. The loss of strength in water-saturated conditions during emergence cycles ranged from 8.54 % to 23.91 %, with a mean value of 13.39 %. The values from submergence formation reveal a 9.72–36.84 % decline, when the results of UCS of samples in dry settings are compared to all wet conditions. Various relationships and empirical equations linking and estimating the physical and mechanical properties of the emergence and submergence sedimentary cycles have been developed, which can assist in subsurface reservoir modeling in the absence of core measurements. The derived relationships and empirical equations can also be utilized as analogues for other marl-limestone successions in similar geological settings.
Background:
Neutrophil-to-lymphocyte ratio (NLR) was introduced as a potential inflammatory marker in sickle cell disease (SCD). This study aimed to evaluate the impact of hydroxyurea (HU) treatment ...on the value of NLR and some inflammatory mediators in SCD.
Methods:
The hematological parameters and clinical events were analyzed in 35 children with SCD under HU treatment and followed up for 1 year and in 20 healthy controls. Enzyme-linked immunosorbent assay was performed for the evaluation of proinflammatory cytokines, including interleukin (IL) 6, IL-8, high-sensitivity C-reactive protein (hs-CRP), and tumor necrosis factor α (TNF-α).
Results:
Hydroxyurea significantly improves most of the hematological parameters in children with SCD. The percentages of hemoglobin fraction S, serum levels of TNF-α and IL-6 were significantly decreased when compared to baseline value but did not reach the value of the healthy control. The HU treatment led to a significant decrease in NLR compared to the baseline values and reached healthy control values. Neutrophil-to-lymphocyte ratio was positively correlated with hs-CRP, TNF-α, and IL-8 serum levels and negatively correlated with percentage of fetal hemoglobin and hematocrit values. The cutoff value of NLR to expect a response to HU among SCD was 3.0, with 76% specificity and 85% sensitivity (area under the curve: 0.85, P < .0001). In conclusion, hydroxyurea induced a decrease in NLR and inflammatory cytokines, which represent a biomarker of inflammation in SCD. The calculation of NLR is a straightforward and cheap method for SCD outcome prediction in young children.
Melanoma is the sixth most frequent malignancy. It represents 1.7% of all cancer cases worldwide. Many risk factors are associated with melanoma including ultraviolet radiation skin phenotype, ...Pigmented Nevi, Pesticides, and genetic and epigenetic factors. Of the main epigenetic factors affecting melanoma are microribonucleic acids (miRNAs). They are short nucleic acid chains that have the potential to prevent the expression of a number of target genes. They could target a number of genes related to melanoma initiation, stemness, angiogenesis, apoptosis, proliferation, and potential resistance to treatment. Additionally, they can control several melanoma signaling pathways, including P53, WNT/-catenin, JAK/STAT, PI3K/AKT/mTOR axis, TGF- β, and EGFR. MiRNAs also play a role in the resistance of melanoma to essential treatment regimens. The stability and abundance of miRNAs might be important factors enhancing the use of miRNAs as markers of prognosis, diagnosis, stemness, survival, and metastasis in melanoma patients.
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The present study involves synthesis a new series of α-aminophosphonates 2a-f and 4a-d derivatives in good yield with a simple workup via Kabachnik-Fields reaction in the presence of lithium ...perchlorate as Lewis acid catalyst. All the newly synthesized compounds were confirmed using various physical, spectroscopic, and analytical data. The in vitro anticancer activities of each compound were evaluated against colorectal carcinoma Colon cancer (HCT-116) and Epdermoid carcinoma (HEP2) and also Human lung fibroblast normal cell line (WI38) compared with Doxorubicin. The results showed that Compounds 2a, 4b and 4d exhibited more potent inhibitory activity for Epdermoid Carcinoma (HEP2) compared with doxorubicin. For colon carcinoma cells (HCT-116) Compounds 2a, 2d and 4b gave the strongest activity among all compounds compared with doxorubicin. Moreover, all designed structures were docked into the active site of VEGFR2 and FGFR1 proteins. The result reveals that compound 2b and have the strongest inhibitory activity of the VEGFR2 and FGFR1 proteins indicating that these substances might conceivably operate as VEGFR2 and FGFR1 inhibitors and hence might take role in anticancer activities with various binding interactions. The 3D-QSAR models produced strong statistical results since they were defined by PLS factors 4 and confirmed by parameters as R2, R2 CV, Stability, F-value, P-value, RMSE, Q2, and Pearson-r.
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