Experimental Model For Study Research Articles

Determination of Experimental Characteristics of a Jet-vortex Pump

A methodology has been developed and the results of experimental studies of high-pressure jet-vortex pump models with a mixing chamber and working nozzle area ratio of 3.429 and 3.795 have been obtained. In the flow part of the pump, inclined guide elements for swirling the mixed flows are installed. An increase in the velocity of swirling screw jets increases the level of turbulence, intensifies the energy exchange of the mixed media, and improves the conditions for transferring kinetic energy from the working flow to the injected one. Improvement of the flow mixing mechanism allows increasing the energy efficiency of jet pumps. The velocity of swirling screw jets is determined by the angle of inclination of the guide elements and the flow rate of the mixed flows. The efficiency of simultaneous swirling of the mixed media may be less than the efficiency of swirling a separate flow if there is a difference in the directions of the velocity vectors of the swirling jets. There has been obtained the dependence of the injection coefficient on the Reynolds number of the working flow, pressure and energy characteristics for a straight-through jet pump for the case of swirling of the exclusively injected flow and simultaneous swirling of the working and injected flows. According to the results of the conducted studies, an increase in the injection coefficient, relative pressure and efficiency caused by swirling of the mixed flows was established by 26.34%, 19.43% and 23.75%, respectively.

An experimental and kinetic modeling study of the ignition of methane/n-decane blends

An experimental and kinetic modeling study of the combustion of methane/n-decane blends is performed. Ignition delay times (IDTs) of the pure fuels in addition to their blends are measured using both a shock tube and a rapid compression machine at three different methane/n-decane (mol%) compositions of 99/1 (M99D1), 95/5 (M95D5), and 80/20 (M80D20) in ‘air’, over the temperature range of 610–1495 K, at a pressure of 30 bar. A new chemical kinetic mechanism, GalwayMech1.0, is proposed to describe the combustion of these blends and is validated against the new IDT data including 1st-stage and total IDTs as well as existing experimental n-decane data available in the literature. Sensitivity analyses reveal that H-atom abstraction from n-decane by methyl peroxy radicals (CH3Ȯ2) play an important role in promoting blend reactivity at intermediate temperatures, which is not observed for pure n-decane. By investigating the effect of the n-decane concentration on the ignition characteristics, we found that the low ignition temperature limit is extended with increasing n-decane content with a non-linear reactivity-promoting effect. Flux analyses reveal that CH4 oxidation in the blends is initiated via CH4 + ȮH = ĊH3 + H2O, driven by the ȮH radicals produced from the early oxidation of n-decane and the CH3Ȯ2 radicals formed from CH4 oxidation which subsequently accelerates nC10H22 consumption via H-atom abstraction. Comparisons of CH4/nC10H22 and H2/nC10H22 blends from a previous study demonstrate consistently higher reactivity for hydrogen blending compared to methane and that the magnitude of this increase diminishes with increasing n-decane content. Finally, we also compare our current model predictions of our new data with other n-decane models available in the literature.

Experimental and prediction model study on permeability of methane hydrate-bearing carbonate sand−silt mixtures

Experimental and prediction model study on permeability of methane hydrate-bearing carbonate sand−silt mixtures

Modeling of Basin Type Single Slope Solar Still Under Local Climate Conditions in Yemen

The economic crises and instability caused by the conflict in Yemen prevents the establishment of medium and large-scale water desalination plants to overcome the sever water scarcity in the high population major cities. This paper investigates small scale solar still water desalination technology as a potential candidate to aid with the production of fresh water to reduce the accelerated depletion of underground water reserves in Yemen. Water stills have the advantage of low capital cost and no operational cost as it utilizes the high solar radiation intensity in the coastal areas to evaporate water. This paper proposes and compares two models to simulate the performance of solar still following steady-state and transient modelling approaches, with in-depth evaluation of the different parameters affecting the performance. The transient model showed better prediction of the temperature profiles of the solar still when compared to other experimental and mathematical modelling studies. The small scale solar still showed water production yield of about 1.9 kg/day, with maximum hourly yield of about 0.27 kg/h.

Sustainable Photodegradation of Amoxicillin in Wastewater with a Nickel Aluminate and ZnO Heterosystem Oxides: Experimental and Gaussian Process Regression Modeling Studies

The wastewater generated by the pharmaceutical industry poses a risk to the environment due to undesirable characteristics such as low biodegradability, high levels of contaminants, and the presence of suspended solids, in addition to the high load of organic matter due to the presence of drugs and other emerging products in the effluent. This study aims to reduce the impact of wastewater pollution by removing amoxicillin (AMO) antibiotics as an organic pollutant. In this concept, two synthesized catalysts, NiAl2O4 and ZnO, are sensitive oxides to light energy. The prepared materials were then characterized using X-ray diffraction, UV–vis solid reflectance diffuse, Raman spectroscopy, scanning electron microscopy, BET, and ATR-FTIR spectroscopy. The effects of principal operating parameters under sunlight, namely, the percentage of the mixture of NiAl2O4 and ZnO, the pH of the medium, and the initial concentration of the antibiotic were studied experimentally to determine the optimal conditions for achieving a high degradation rate. The results showed that photodegradation is higher at a pH of 6, with a weight percentage of the mixture of 50% for both catalysts in 1 g/L of the total catalyst dose. Then, the effect of the initial concentration of AMO on the photodegradation reaction showed an important influence on the photodegradation process; as the degradation rate decreases, the initial AMO concentration increases. A high degradation rate of 92% was obtained for an initial AMO concentration of 10 mg/L and a pH of 6. The kinetic study of degradation established that the first-order model and the Langmuir–Hinshelwood (LH) mechanism fit the experimental data perfectly. The study showed the success of using heterosystem photocatalysts and sustainable energy for effective pharmaceutical removal, which can be extended to treat wastewater with other organic emerging pollutants. On the other hand, modeling was introduced using Gaussian process regression (GPR) to predict the degradation rate of AMO under sunlight in the presence of heterogeneous ZnO and NiAl2O4 systems. The model evaluation criteria of GPR in terms of statistical coefficients and errors show very interesting results and the performance of the model used. Where statistical coefficients were close to one (R = 0.9981), statistical errors were very small (RMSE = 0.1943 and MAE = 0.0518). The results suggest that the model has a strong predictive power and can be used to optimize the process of AMO removal from wastewater.

Investigation of adsorption behavior of eriochrome black T on mesoporous silica aerogel: experimental and molecular modeling studies

Investigation of adsorption behavior of eriochrome black T on mesoporous silica aerogel: experimental and molecular modeling studies

An experimental and kinetic modeling study on the auto-ignition of ammonia/butan-1-ol mixtures

Ignition delay times (IDTs) of ammonia(NH3)/butan-1-ol mixtures with NH3/butan-1-ol mole ratios of 100/0, 95/5, 90/10 and 70/30 were measured behind reflected shock waves in a shock tube over a range of experimental conditions: temperature range of 1100 – 2000 K, pressures of 0.14 and 0.5 MPa, equivalence ratios of 0.5, 1.0 and 2.0. A new NH3/butan-1-ol reaction mechanism, capable of predicting the experimental results reliably, was developed. Chemical kinetic analyses were performed with the model. It is demonstrated that increasing the content of butan-1-ol in the reaction system results in a non-linear trend of shortening on the IDTs of mixtures, adding 5 % molar fraction of butan-1-ol results in shortening rates of over 70 %. As the butan-1-ol blending ratio increases from 5 % to 30 %, the discrepancy in IDT of the mixture between equivalence ratios of 0.5 and 1.0 diminishes while it remains more pronounced between equivalence ratios of 1.0 and 2.0. The presence of butan-1-ol does not change the oxidation pathways of the NH3 mixture. R72(NH3 + M = NH2 + H + M) and R75(NH2 + HO2 = NH3 + O2) are key reactions to activate chain reactions of the NH3 mixture during the initial reaction stage, for a temperature of 1500 K, a pressure of 0.14 MPa, and an equivalence ratio of 1.0. Reactive radicals produced through the process of butan-1-ol oxidation result in a significant increase in the initial dehydrogenation consumption rate of NH3, by a factor of 5 ∼ 6 powers of ten, accelerating chain reactions.

Pullout Capacity of Piles in Unsaturated High Plasticity Clayey Soil: An Experimental Model Study

Pullout Capacity of Piles in Unsaturated High Plasticity Clayey Soil: An Experimental Model Study

Experimental and theoretical model study on grouting reinforcement effect of fractured rock mass

The mechanical properties of fractured rock mass have an important influence on the safety and stability of underground engineering. Grouting is a common way to reinforce fractured rock mass. The uniaxial compression tests of red sandstone specimens with different prefabricated crack inclination angles before and after grouting were carried out. Based on the load-deformation data and synchronous image acquisition, the mechanical properties, crack propagation law and failure mode of the specimens before and after grouting were studied. The results show that the peak strength and elastic modulus of the ungrouted specimen increase with the increase of the inclination angle of the prefabricated crack. Compared with the ungrouted specimen, grouting can significantly improve the peak strength and elastic modulus of the specimen. The cracks of the ungrouted specimen mainly initiate from the tip of the prefabricated crack, and the cracks of the grouting specimen mainly initiate from the upper and lower surfaces of the specimen and the far field. Based on the macroscopic and microscopic damage theory, the constitutive model of grouting rock mass is proposed. By comparing with the experimental data, the rationality of the constitutive model is verified.

Thermal and rheological behavior of aluminium-doped zinc oxide nanofluids: Experimental study and application of artificial neural network model

In this study, the influence of Al-doping concentration on the thermal and rheological characteristics of pristine zinc oxide (ZnO) nanofluids was investigated across a range of temperatures and nanoparticle concentrations. A multilayer perceptron (MLP) artificial neural network (ANN) with an optimized topology was employed to model the thermal conductivity and viscosity of nanofluids. The addition of 0.13 M of Al-doped zinc oxide nanoparticles at 1 % rate led to a remarkable 64 % increase in the thermal conductivity of the base fluid (50:50 ratio water + ethylene glycol mixture). Furthermore, incorporating 1 % of these Al-doped nanoparticles outperformed pure zinc oxide, resulting in a 44 % boost in thermal conductivity. The enhanced heat transfer capabilities of Al-doped zinc oxide were evident across different doping and nanoparticle concentrations. The viscosity of nanofluids increases with an increase in nanoparticle concentration and decreases with an increase in temperature. ZnO and Al-doped ZnO nanoparticles have been prepared and studied their structural, morphological and elemental properties using XRD, SEM and EDS respectively. The predicted thermal and rheological behaviours are in close agreement with the experimental values.

Insights into the adsorption mechanism of chlorpyrifos on activated carbon derived from prickly pear seeds waste: An experimental and DFT modeling study

The removal of chlorpyrifos (CPF) from water was achieved using activated carbon (AC) derived from prickly pear seeds (PPS) wastes, developed through chemical activation with phosphoric acid. Several physico-chemical characterization methods were employed. The determination of surface functions using the Boehm assay indicated that the processed AC predominantly possesses acidic functions. The results obtained from the Boehm assay were corroborated by the pH value of the point of zero charge (pHpzc), which was equal to 2.5. Specific area calculation by the BET (Brunauer Emmett Teller) method revealed a large specific area (SBET) of 1077.66 m2 g⁻1. Adsorption experiments of CPF on AC demonstrated that the pseudo-second order (PSO) model and the Freundlich model were the most suitable for kinetic and isothermal modeling, respectively. The maximum CPF adsorption capacity of the PPS AC was found to be approximately 35 mg g⁻1. A theoretical study employing the density functional theory (DFT) was conducted using the B3LYP/6-311G (d, p) method. The most reliable adsorption energy (Eads) and Gibbs free energy (ΔGads) values between CPF and the functional groups on the AC surface were calculated. Results indicated a strong interaction between the lactone group of AC and CPF (ΔGads = −7.15 kcal mol⁻1, ΔEads = −21.55 kcal mol⁻1) and the hydroxyl group (ΔGads = −6.61 kcal mol⁻1, ΔEads = −20.66 kcal mol⁻1). This study demonstrates that activated carbon possesses significant adsorption power, making it highly effective for depolluting water contaminated by pesticides. The application of the theoretical DFT method enhances the understanding of the adsorption phenomenon of CPF on AC.

Nocturnal atmospheric synergistic oxidation reduces the formation of low-volatility organic compounds from biogenic emissions

Abstract. Volatile organic compounds (VOCs) are often subject to synergistic oxidation by different oxidants in the atmosphere. However, the exact synergistic-oxidation mechanism of atmospheric VOCs and its role in particle formation remain poorly understood. In particular, the reaction kinetics of the key reactive intermediates, organic peroxy radicals (RO2), during synergistic oxidation is rarely studied. Here, we conducted a combined experimental and kinetic modeling study of the nocturnal synergistic oxidation of α-pinene (the most abundant monoterpene) by O3 and NO3 radicals as well as its influences on the formation of highly oxygenated organic molecules (HOMs) and particles. We find that in the synergistic O3 + NO3 regime, where OH radicals are abundantly formed via decomposition of ozonolysis-derived Criegee intermediates, the production of CxHyOz HOMs is substantially suppressed compared to that in the O3-only regime, mainly because of the depletion of α-pinene RO2 derived from ozonolysis and OH oxidation by those arising from NO3 oxidation via cross reactions. Measurement–model comparisons further reveal that the cross-reaction rate constants of NO3-derived RO2 with O3-derived RO2 are on average 10–100 times larger than those of NO3-derived RO2 with OH-derived RO2. Despite a strong production of organic nitrates in the synergistic-oxidation regime, the substantial decrease in CxHyOz HOM formation leads to a significant reduction in ultralow- and extremely low-volatility organic compounds, which significantly inhibits the formation of new particles. This work provides valuable mechanistic and quantitative insights into the nocturnal synergistic-oxidation chemistry of biogenic emissions and will help to better understand the formation of low-volatility organic compounds and particles in the atmosphere.

Experimental Study of Erosion Prevention Model by Bio-Cement Sand

Microbially induced carbonate precipitation (MICP) technology is employed to reinforce the surface soil of a dam, aiming to prevent erosion caused by water flow and damage to the dam slope. The relationship between penetration depth, calcium carbonate content, and bonding depth was investigated at eight measuring points on the sand slope surface of a mold under different reinforcement durations. It was observed that as grouting reinforcement times increased, there was a gradual increase in calcium carbonate content but a rapid rise in penetration resistance. Moreover, the bonding depth of sand on the bio-reinforced sand slope increased with higher levels of calcium carbonate content. Microbial grouting reinforcement enhanced soil particle bonding force, requiring water flow to overcome this force for activation of sand particles. Consequently, microbial grouting reinforcement significantly improved shear strength and critical starting flow velocity on sand slope surfaces. The experimental results demonstrated that after MICP surface treatment through spraying, a dense and water-stable hard shell layer composed of bonded calcium carbonate and soil particles formed continuously on sample surfaces, effectively enhancing the strength and erosion resistance of sandy soils. These findings provide reliable evidence for silt slope reinforcement and dam erosion prevention.

Recovery of electrical power from exhaust air—role of vertical axis wind turbine

AbstractThis article explores the potential of regeneration of power from unnatural wind sources with the help of vertical axis wind turbines (VAWT). Researchers are searching for urban as well as industrial wind sources, which can be useful as the natural wind source to obtain electrical energy and utilize it. The wind sources considered here are the exhaust of the cooling or ventilation fans used in buildings, industries, and other places. The Darrieus VAWT extracts wind power from the exhaust air and reduces the power consumption of the concerned electrical drives. These uncommon energy sources have an inherent capability to recover a significant amount of energy without polluting the environment with less payback period. Recovered energy can be suitably converted into electrical energy and may be fed back to the power grid without any pollution, thus minimizing the total energy consumption of the building and reducing the cost operations. A detailed study of experimental models with different types of assembly and turbine models is conducted here with power outputs and operational behaviors on the existing systems. Various parameters and factors for existing and new applications are in detail that show the system has no negative impact on regular operation.

Classification of Current Experimental Models of Epilepsy.

This article provides an overview of several experimental models, including in vivo, genetics, chemical, knock-in, knock-out, electrical, in vitro, and optogenetics models, that have been employed to investigate epileptogenesis. The present review introduces a novel categorization of these models, taking into account the fact that the most recent classification that gained widespread acceptance was established by Fisher in 1989. A significant number of such models have become virtually outdated. This paper specifically examines the models that have contributed to the investigation of partial seizures, generalized seizures, and status epilepticus. A description is provided of the primary features associated with the processes that produce and regulate the symptoms of various epileptogenesis models. Numerous experimental epilepsy models in animals have made substantial contributions to the investigation of particular brain regions that are capable of inducing seizures. Experimental models of epilepsy have also enabled the investigation of the therapeutic mechanisms of anti-epileptic medications. Typically, animals are selected for the development and study of experimental animal models of epilepsy based on the specific form of epilepsy being investigated. Currently, it is established that specific animal species can undergo epileptic seizures that resemble those described in humans. Nevertheless, it is crucial to acknowledge that a comprehensive assessment of all forms of human epilepsy has not been feasible. However, these experimental models, both those derived from channelopathies and others, have provided a limited comprehension of the fundamental mechanisms of this disease.

Effect of sprayable, highly adhesive hydrophobized gelatin microparticles on esophageal stenosis after endoscopic submucosal dissection: an experimental study in a swine model.

Esophageal mucosal resection for superficial esophageal cancer can lead to postoperative esophageal stricture, with current preventive measures being insufficient. Sprayable wound dressings containing hydrophobized microparticles exhibit strong adhesion. This study aimed to investigate the preventive effects of hydrophobized microparticles on esophageal stenosis following endoscopic submucosal dissection. Circumferential esophageal endoscopic submucosal dissection was performed on miniature swine (n = 6). Swine were categorized into two groups: those sprayed with hydrophobized microparticles (sprayed group) and those not sprayed (non-sprayed group). Hydrophobized microparticles were sprayed onto the sprayed group on Days 0, 3, and 7 of endoscopic submucosal dissection. The non-sprayed group underwent endoscopy on the same days. Esophageal stricture rate, submucosal inflammatory cell infiltration, submucosal fibrosis, and thickening of the muscular layer were compared between the groups on Day 14 of endoscopic submucosal dissection. Spraying of hydrophobized microparticles was easily performed using an existing endoscopic spraying device. The esophageal stricture rate was significantly lower in the sprayed group than in the non-sprayed group (76.1% versus 90.6%, p < 0.05). The sprayed group showed suppression of inflammatory cell infiltration in the submucosal layer (p < 0.01) and thickening of the muscular layer (p < 0.01). Sprayable tissue-adhesive hydrophobized microparticles reduce the stricture rate after esophageal ESD by inhibiting inflammatory cell infiltration, submucosal fibrosis, and thickening of the muscular layer. The use of hydrophobized microparticles for preventing post-endoscopic submucosal dissection esophageal stenosis offers a promising avenue for clinical applications in endoscopic procedures, potentially improving patient outcomes.

SGLT2 Inhibitors and Their Effect on Urolithiasis: Current Evidence and Future Directions.

Urolithiasis (UL) is increasingly prevalent due to rising cardiorenometabolic diseases, posing significant management challenges despite advances in urological techniques. Sodium-glucose cotransporter-2 (SGLT2) inhibitors, primarily used for type 2 diabetes mellitus, chronic kidney disease, and heart failure, have emerged as a potential novel approach for UL treatment. These inhibitors may help reduce the risk of urolithiasis, particularly in patients with diabetes, by improving glycemic control and altering urinary chemistry, which are crucial factors in stone formation. However, the changes in urinary composition induced by SGLT2 inhibitors might also increase the risk of uric acid stone formation. This review evaluates the potential of SGLT2 inhibitors in managing UL, highlighting both the benefits and the risks. While these inhibitors show promise in reducing new and recurrent urinary stones in patients with diabetes, data on their effects in patients without diabetes who form stones are limited. Current human evidence largely comes from post hoc analyses of randomized controlled trials (RCTs) and large-scale database studies, with only one study providing detailed stone composition data. Experimental studies in animal models and cell lines have focused on calcium oxalate (CaOx) stones, showing that SGLT2 inhibitors specifically target CaOx stone formation and related renal inflammation. Although primarily studied for CaOx stones, their potential impact on other calcium-containing stones, such as calcium phosphate, remains promising. Further research is needed to explore their therapeutic potential and optimize treatment strategies.

Integrated experimental and thermodynamic modelling study of phase equilibria in the “CuO0.5”-PbO-CaO system in equilibrium with Cu/Pb metal

Phase equilibria studies were undertaken on the “CuO0.5”-PbO-CaO system in equilibrium with Cu/Pb metal as part of the integrated experimental and thermodynamic modelling study of phase equilibria in the Cu-Pb-Zn-Fe-Ca-Si-Al-Mg-O-S-(As, Sn, Sb, Bi, Ag, Au, Ni, Cr, Co and Na) gas/oxide liquid/matte/speiss/metal/solids system in support of the development and optimisation of pyrometallurgical processes. The equilibration and quenching technique followed by the electron probe X-ray microanalysis (EPMA) was used in the present study. The primary phase fields of massicot (PbO), copper plumbite (Cu2PbO2), cuprite (Cu2O) and lime (CaO) were experimentally characterised. The experimental data obtained in the present study, as well as available literature data on the phase equilibria and thermodynamics of the “CuO0.5”-PbO-CaO system in equilibrium with Cu/Pb were used for the optimisation of the model parameters of the discussed system in agreement with the Cu-Pb-Zn-Fe-Ca-Si-Al-Mg-O-S-(As, Sn, Sb, Bi, Ag, Au, Ni, Cr, Co and Na) gas/oxide liquid/matte/speiss/metal/solids system to obtain a self-consistent set of parameters of the thermodynamic model for all phases. The predicted liquidus surface of the “CuO0.5”-PbO-CaO system was presented for the first time in the complete range of temperatures and compositions.

Experimental study of a medical data analysis model based on comparative performance of classification algorithms

Experimental study of a medical data analysis model based on comparative performance of classification algorithms

The Use of Organoclays as Excipient for Metformin Delivery: Experimental and Computational Study

This work combines experimental and computational modeling studies for the preparation of a composite of metformin and an organoclay, examining the advantages of a Tunisian clay used for drug delivery applications. The clay mineral studied is a montmorillonite-like smectite (Sm-Na), and the organoclay derivative (HDTMA-Sm) was used as a drug carrier for metformin hydrochloride (MET). In order to assess the MET loading into the clays, these materials were characterized by means of cation exchange capacity assessment, specific surface area measurement, and with the techniques of X-ray diffraction (XRD), differential scanning calorimetry, X-ray fluorescence spectroscopy, and Fourier-transformed infrared spectroscopy. Computational molecular modeling studies showed the surface adsorption process, identifying the clay–drug interactions through hydrogen bonds, and assessing electrostatic interactions for the hybrid MET/Sm-Na and hydrophobic interactions and cation exchange for the hybrid MET/HDTMA-Sm. The results show that the clays (Sm-Na and HDTMA-Sm) are capable of adsorbing MET, reaching a maximum load of 12.42 and 21.97 %, respectively. The adsorption isotherms were fitted by the Freundlich model, indicating heterogeneous adsorption of the studied adsorbate–adsorbent system, and they followed pseudo-second-order kinetics. The calculations of ΔGº indicate the spontaneous and reversible nature of the adsorption. The calculation of ΔH° indicates physical adsorption for the purified clay (Sm-Na) and chemical adsorption for the modified clay (HDTMA-Sm). The release of intercalated MET was studied in media simulating gastric and intestinal fluids, revealing that the purified clay (Sm-Na) and the modified organoclay (HDTMA-Sm) can be used as carriers in controlled drug delivery in future clinical applications. The molecular modeling studies confirmed the experimental phenomena, showing that the main adsorption mechanism is the cation exchange process between proton and MET cations into the interlayer space.