7 research outputs found
Modeling ionic liquids mixture viscosity using Eyring theory combined with a SAFT-based EOS
This work aims to calculate the viscosities of ionic liquid mixtures using the Eyring theory combined with the SAFT-VR Morse EOS. The free volume theory was used to correlate the pure viscosity of ionic liquids (ILs) and solvents. Three model parameters have been adjusted using experimental viscosity data of ILs between 282 K and 413 K and 1 bar to 350 bar. The average ARD%, Bias%, and rmsd between model estimation and viscosity experimental data for pure ILs have been obtained 4.9 %, 1.015 %, and 0.67, respectively. The average error of the proposed model tends to increase at a pressure higher than 200 bar. The average ARD% for [C2mim][Tf2N] and [C6mim][Tf2N] is about 3.8 % and 3.4 % at pressures lower than 200 bar, while the average ARD% values increase sharply at higher pressures. This is due to the weak performance of the SAFT-VR Morse EOS for the calculation of IL density at high pressures. The SAFT-VR Morse EOS has been coupled with the Eyring theory, and the Redlich-Kister mixing rule to estimate the mixture viscosity of ILs-ILs and ILs-solvent systems. The thermal contribution of excess activation free energy has been calculated using the Redlich-Kister mixing rule with four adjustable parameters. The average ARD%, rmsd, and Bias% for fifteen binary mixtures have been obtained 3.9 %, 2.51, and 0.57 %, respectively. The average error values for mixture viscosity of ILs-polar solvent are higher than non-polar solvents. In the case of binary IL-IL systems, the model results are in good agreement with experimental data. The model performance has been evaluated using the viscosity deviation property. The SAFT-VR Morse EOS predicts the negative viscosity deviation. The strong attractive interaction in the mixture than a pure component is the major contribution to negative viscosity deviation. The results show that the new model can calculate the mixture viscosity and viscosity deviation of binary systems satisfactory. The obtained error values of mixture viscosity show that the Eyring theory can be coupled with a SAFT-based EOS to calculate the viscosity of ILs over a wide range of pressures and temperatures satisfactory
Practice of intercropping and its impact on legume productivity in Egypt
In Egypt, conserving irrigation water and raising crop output are significant concerns. Egypt's climate ranges from semi-arid and arid to desert. The number of summer legumes cultivated on a per-capita basis is declining. Excessively applied nitrogen (N) mineral fertilization and irrigation water are widespread agricultural techniques that harm the quality of the soil and the surrounding environment. It should be possible to increase overall agricultural yield while working with scarce agricultural resources through intercropping. In developing countries, intercropping is the most common farming system for increasing and maintaining agricultural production. As a widely spaced crop, maize provides ample opportunity for the practice of intercropping. Legumes are well-known for their effectiveness as intercropping companions. In light of this information, an investigation into the possibility of intercropping maize with legumes, specifically groundnut and green gram, was carried out. Seeds for groundnuts and green grams were sown between rows of paired row maize. The results demonstrated that the intercropping system had no considerable impact on maize grain and straw yields. However, there was a substantial disparity in total biomass production between the experiments; maize and groundnut (2:3) recorded the highest yield, followed by groundnut (2:2) and green gram (2:3). The land equivalent ratio (LER) unequivocally demonstrated the benefits of intercropping, and the highest LER was achieved by growing maize and groundnut (2:1)
Converting Coordinates Between the Local Geodetic Reference and the Global Geodetic Reference for Selective Sites in Babil Province
A geodetic transformation is a mathematical operation that takes a point's coordinates in one coordinate system and returns the same coordinates in another coordinate system. This study aims to show the compatibility between global positioning system coordinates and the local maps in Iraq; this compatibility will be made for locations in Babil province. In the study area, fifteen control points have been chosen. GPS measures geographic and projected coordinates depending on the Universal Transverse Mercator projection and the World Geodetic System 1984 datum. In Iraq, the measured geographic coordinates are converted to projected coordinates using a geographic information system based on Clarke 1880 ellipsoid. To facilitate the conversion of the coordinates, both formulas and parameters are provided for any point in the study area between the two systems using a GPS receiver and ArcGIS software. The present study shows that the differences in easting coordinates are about -287.630 m, while the differences in northing coordinates reach 278.525 m. It is concluded that the various datums might play a significant role in producing maps and updating those maps for engineering works
Study of dam sediment distribution using experimental area-reduction method Case study: Karun Dam
Dam construction is one of the measures that is inevitable in many cases and must be done to supply drinking water, agricultural uses and electricity generation. There are many challenges to a successful dam project, and the managers of each project must consider the appropriate solutions for them. One of the studies that is done in dam design is sedimentation in dam reservoirs. The experimental area-reduction method is a very common technique that obtains the sediment distribution in depth and longitudinal profile. This technique shows that sediment accumulation is not limited to the bottom reservoirs. Sediment accumulation in a reservoir is usually distributed below the top of the protection reservoir or normal water level. In this study, the distribution of sediment in the reservoir of Karun Dam after a period of 65 years has been done using the experimental area-reduction method. Elevation-volume and elevation-area curves of the dam reservoir are obtained after the useful life of the dam and sediment deposition. The results showed that after 65 years, 106.47·106 m3 of sediment is deposited in the reservoir of the dam and the useful volume of the reservoir is significantly reduced. Also, up to a height of 36.4 m, the dam reservoir is filled with sediment. Therefore, no valve should be placed up to this height
Thermal performance improvement for parabolic trough solar collectors integrated with twisted fin and nanofluid: Modeling and validation
The low thermal efficiency of parabolic trough solar collectors (PTSCs) is a major drawback that has hindered their development as a viable renewable energy resource. Among the available methods to enhance the thermal performance of PTSCs, installing internal fins within the collector tube is one of the most reliable, economical, and straightforward passive techniques. However, while internal fins can significantly improve thermal performance in turbulent flows, they also lead to a substantial increase in pumping work. Here, we demonstrate that with an optimal design of helical fins, the thermal efficiency of PTSCs can be improved without causing significant pressure losses through the receiver tube. The results proved that higher thermal efficiency and lower pressure losses were achieved when annular fins are replaced by an axial helical insert. Installation of a helical fin with 4 turns and a height of 4 mm led to a 4.5 % increase in thermal efficiency (η) while raising the friction factor (f) by 30 %. Optimal performance was observed with helical fins having 10 turns. For instance, at Re = 105, switching from 16 to 4 turns of 8 mm helical fins resulted in η and Nu enhancements, and f reduction of 1.6 %, 33 % and 64 %, respectively. While these changes were 2.0 %, 55 % and 54 % when n reduced from 16 to 10
Assessment of Urban Green Space Dynamics Influencing the Surface Urban Heat Stress Using Advanced Geospatial Techniques
Urban areas are mostly heterogeneous due to settlements and vegetation including forests, water bodies and many other land use and land cover (LULC) classes. Due to the overwhelming population pressure, urbanization, industrial works and transportation systems, urban areas have been suffering from a deficiency of green spaces, which leads to an increase in the variation of temperature in urban areas. This study investigates the conceptual framework design towards urban green space (UGS) and thermal variability over Kolkata and Howrah city using advanced remote sensing (RS) and geospatial methods. The low green space is located in the highly built-up area, which is influenced by thermal variations. Therefore, the heat stress index showed a high area located within the central, north, northwestern and some parts of the southern areas. The vegetated areas decreased by 8.62% during the ten years studied and the other land uses increased by 11.23%. The relationship between land surface temperature (LST) and the normalized difference vegetation index (NDVI) showed significant changes with R2 values between 0.48 (2010) and 0.23 (2020), respectively. The correlation among the LST and the normalized difference built-up index (NDBI) showed a notable level of change with R2 values between 0.38 (2010) and 0.61 (2020), respectively. The results are expected to contribute significantly towards urban development and planning, policymaking and support for key stakeholders responsible for the sustainable urban planning procedures and processes
Advanced machine learning computations for estimation of hydrogen solubility in oil samples: Model comparisons and validation
For analyzing hydrogenation process for treatment of petroleum-based fuels, solubility of hydrogen in the feed should be well correlated. The main correlation factors are temperature and pressure which have a great effect on hydrogen solubility. This research paper presents the development of three models for predicting the solubility of hydrogen gas (H2) in diesel. Pressure and Temperature are the input parameters and solubility is single output. The models were fine-tuned using the Bat Algorithm (BA). The three models include Orthogonal Matching Pursuit Regression (OMP), K Nearest Neighbors Regression (KNN), and Tweedie Regression (TDR). The results of the study revealed that the OMP model achieved the highest level of accuracy, with an R2 score of 0.98, and the least RMSE and MAE error rates of 0.24 and 0.19, respectively. The KNN model also performed well with an R2 score of 0.92, an RMSE of 0.42, and an MAE of 0.37. The TDR model had the lowest accuracy compared to the other two models. These results imply that the OMP model is the most suitable one for predicting H2 solubility. The models can be used to enhance the efficiency of fuel production by providing accurate predictions of H2 solubility