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1-[3-({[bis(2-methylpropyl)carbamothioyl]amino}carbonyl)benzoyl]-3, 3-bis(2-methylpropyl)thiourea
(International Union of Crystallography, 2013-08-03) Selvakumaran, N; Karvembu, R; Ng, Seik Weng; Tiekink, Edward R. T.
The title compound, C26H42N4O 2S2, adopts a shallow U-shape as both pendant arms of the 1,3-substituted benzene ring are orientated in the same direction. The thione S atoms lie to the same side of the benzene ring and the carbonyl O atoms to the other. The most prominent feature of the crystal packing is the formation of inversion dimers mediated by N - H⋯S hydrogen bonds. One of the 2-methylpropyl groups is statistically disordered over two positions. © 2013 Selvakumaran et al.
1-Benzoyl-3,3-bis(propan-2-yl)thiourea
(International Union of Crystallography, 2010-07-24) Gunasekaran, N; Karvembu, R; Ng, Seik Weng; Tiekink, Edward R. T.
Two independent thiourea derivatives comprise the asymmetric unit of the title compound, C14H20N2OS. The major difference between the mol-ecules relates to a twist in the relative orientation of the benzene rings [torsion angles = 4.5 (2) and -19.9 (2)° for the two independent mol-ecules]. The thio-carbonyl and carbonyl groups lie to opposite sides of the mol-ecule as there are twists about the central N - S bond [torsion angles = 83.90 (15) and 81.77 (15)°]. Supra-molecular chains extending parallel to [101] with a stepped topology and mediated by N - H⋯O hydrogen bonding feature in the crystal structure. C - H⋯O and C - H⋯π inter-actions are also present.
1-Benzoyl-3,3-bis-(2-methylpropyl)thiourea
(International Union of Crystallography, 2011-02-12) Selvakumaran, N; Karvembu, R; Ng, Seik Weng; Tiekink, Edward R.T.
The title compound, C16H24N2OS, is twisted about the central N(H) - C bond with the C - N - C - S torsion angle being 119.6 (3)°. The carbonyl O and thione S atoms are directed to opposite sides of the molecule, a conformation that allows for the formation of a linear supramolecular chain comprising alternating eight-membered {⋯HNCS} 2 and 14-membered {⋯HCNCNCO}2 synthons.
1-Benzoyl-3,3-dibutylthiourea
(International Union of Crystallography, 2010-09-25) Gunasekaran, N; Karvembu, R; Ng, Seik Weng; Tiekink, Edward R. T.
The title molecule, C16H24N2OS, is twisted about the central N(H) - C bond with a C - N(H) - C - N torsion angle of -62.67 (15)°. The carbonyl group is twisted out of the plane of the benzene ring, forming a C - C - C=O torsion angle of -25.06 (17)°. In the crystal, molecules related by centres of symmetry are linked by pairs of inter-molecular N - H⋯S hydrogen bonds, forming eight-membered {⋯HNCS}2 synthons. These are further connected by weak via C - H⋯O contacts, forming a two-dimensional array in the bc plane.
1-Benzoyl-3-(4-chlorophenyl)thiourea dichloromethane hemisolvate
(International Union of Crystallography, 2012-11-10) Selvakumaran, N; Sheeba, M. Mary; Karvembu, R Ng,; Ng, Seik Weng; Tiekink, Edward R. T.
In the title hemisolvate, C14H11ClN2OS·0.5CH2Cl2, an anti disposition is found for the thione and ketone atoms, as well as the N-H H atoms; the dichloromethane C atom lies on a twofold axis. The central chromophore (including the two adjacent ipso C atoms) is planar (r.m.s. deviation = 0.021 Å) owing to the presence of an intramolecular N-H⋯O hydrogen bond, which closes an S(6) loop. Significant twists are evident in the molecule, the dihedral angles between the central moiety and the phenyl and benzene rings being 29.52 (7) and 40.02 (7)°, respectively. In the crystal, eight-membered {⋯HNC= S}2 synthons with twofold symmetry form via N-H⋯S hydrogen bonds. The dimers are connected into a supramolecular chain along [111] by C-H⋯O interactions. The chains stack along the c axis, forming columns which define channels in which the occluded dichloromethane molecules reside.
1-Benzoyl-3-methyl-3-pentylthiourea
(International Union of Crystallography, 2011-04-16) Gunasekaran, N; Jerome, P; Karvembu, R; Ng, Seik Weng; Tiekink, Edward R. T.
Two independent molecules comprise the asymmetric unit of the title compound, C14H20N2OS. These differ in the relative orientations of the pentyl chains [C-C-C-C torsion angles = 176.7 (3) and 176.4 (3)°]. Significant twists are evident in each molecule, the dihedral angles formed between the thiourea and amide residues being 53.47 (17) and 55.81 (17)°. In the crystal, each molecule self-associates via a centrosymmetric eight-membered {⋯HNC S}2 synthon, and these are connected into a supramolecular chain along [110] via C-H⋯O contacts. Disorder is noted for one of the independent molecules in that two orientations (50:50) were resolved for its benzene ring.
2-Phenyl-5,7-bis(prop-2-en-1-yloxy)-4H-chromen-4-one
(International Union of Crystallography, 2008-12-03) Nallasivam, Angannan; Nethaji, Munirathinam; Vembu, Nagarajan; Ragunathan, Venkatraman; Sulochana, Nagarajan
In the title compound, C21H18O4, tthe dihedral angle between the chromene ring system and the pendant phenyl ring is 6.1 (1)°. The crystal structure is stabilized by an intermolecular C - H⋯O and C - H⋯π inter-actions.
3-({[Bis(2-methylpropyl)carbamothioyl]amino}carbonyl)benzamide
(International Union of Crystallography, 2013-06-29) Selvakumaran, N; Karvembu, R; Ng, Seik Weng; Tiekink, Edward R. T.
In the title compound, C17H25N3O2S, the terminal and central amide groups are, respectively, twisted and coplanar with the attached benzene ring [O - C - C - C torsion angles = 22.7 (3) and 5.4 (3)°]. In the central part of the molecule, the amide and thioamide residues are approximately perpendicular [C - N - C - S torsion angle = -104.98 (18)°]. Supramolecular layers with a zigzag topology are formed in the crystal packing by N - H...O, N - H...S and C - H...O interactions; these stack along c, being separated by hydrophobic interactions.
3-Benzoyl-1,1-dibenzylthiourea
(International Union of Crystallography, 2010-09-18) Gunasekaran, N; Karvembu, R; Ng, Seik Weng; Tiekink, Edward R. T.
Two independent thio-urea molecules comprise the asymmetric unit of the title compound, C22H20N2OS. The central N-C(=S)N(H)C(=O) atoms in each molecule are virtually superimposable and each is twisted [C - N - C - S torsion angles = 121.3 (3) and -62.3 (4)°]. The molecules differ only in terms of the relative orientations of the benzyl benzene rings [major difference between the C - N - C - C torsion angles of -146.6 (3) and -132.9 (3)°]. The presence of N - H⋯S hydrogen bonding leads to the formation of supra-molecular chains along the a axis. These are consolidated in the crystal packing by C - H⋯O interactions. The crystal was found to be a combined non-merohedral and racemic twin (twin law 1̄00/01̄0/001), with the fractional contribution of the minor components being approximately 9 and 28%.
3-Benzoyl-1-(2-methoxyphenyl)thiourea
(International Union of Crystallography, 2012-11-03) Selvakumaran, N; Sheeba, M. Mary; Karvembu, R; Ng, Seik Weng; Tiekink, Edward R. T.
In the title compound, C15H14N2O2S, the central C2N2OS moiety is planar (r.m.s. deviation of fitted atoms = 0.0336 Å). This is ascribed to the formation of an S(6) loop stabilized by an intramolecular N-H⋯O hydrogen bond; additional intramolecular N-H⋯O and C-H⋯S contacts are also noted. The dihedral angles between the central unit and the phenyl and benzene rings are 23.79 (7) and 29.52 (5)°, respectively. The thione S and ketone O atoms are mutually anti, as are the N-H H atoms; the O atoms lie to the same side of the molecule. Centrosymmetric eight-membered {⋯HNC=S}2 synthons feature in the crystal packing. The resulting inversion dimers stack along the a axis and are connected into a three-dimensional structure by C-H⋯O and C-H⋯π interactions.
3-{[(Dibenzylcarbamothioyl)amino]carbonyl}benzamide
(International Union of Crystallography, 2013-06-29) Selvakumaran, N; Karvembu, R; Ng, Seik Weng; Tiekink, Edward R. T.
Two independent molecules with quite similar conformations, A and B, comprise the asymmetric unit of the title compound, C23H21N3O2S. The terminal amide substituent is coplanar with the attached benzene ring [the O - C - C - C torsion angles are 174.0 (2) (A) and 6.3 (3)° (B)]. In the same way, the central amide group [C - C - C - O = 7.8 (3) (A) and 11.5 (3)° (B)] is approximately coplanar with the ring to which it is attached. A major twist is noted between the amide and adjacent thioamide residues [C - N - C - S = -109.29 (19) (A) and -112.29 (19)° (B)]. In the crystal, supramolecular chains along [100] are formed by N - H...O and N - H...S hydrogen bonding. These are connected into a three-dimensional architecture by C - H...π and π-π interactions [inter-centroid distance = 3.9157 (12) Å].
{4-Bromo-2-[(2-sulfidophenyl)iminomethyl]phenolato-k3 S,N,O}(triphenylphosphane-kP)nickel(II)
(International Union of Crystallography, 2011-03-12) Muthu Tamizh, M.; Karvembu, R; Varghese, B; Tiekink, Edward R. T.
The NiII atom in the title complex, [Ni(C13H 8BrNOS)(C18H15P)], is coordinated by the N, O and S atoms of he dianionic tridentate ligand, and its square-planar geometry is completed by a phosphane P atom. The dihedral angle between the aromatic rings in the 4-bromo-2-[(2-sulfidohenyl)imino-meth-yl]phenolate ligand is 2.01 (14)°. The most prominent feature of the packing is the presence of supramolecular chains aligned along the a axis, mediated by C - H⋯S interactions.
5,7-Bis(benz-yloxy)-2-phenyl-4H-chromen-4-one
(International Union of Crystallography, 2008-11-29) Nallasivam, Angannan; Nethaji, Munirathinam; Vembu, Nagarajan; Jaswant, Buckle; Sulochana, Nagarajan
In the title compound, C29H22O4, the chromene ring is almost planar with a small puckering [0.143 (2) Å]. The crystal structure is stabilized by C - H⋯O and C - H⋯π inter-actions. Edge-to-face (centroid-centroid distances of 3.894 and 3.673 Å) and face-to-face (centroid-centroid distance of 3.460 Å) π-π-ring electron inter-actions are also observed. © 2008.
5,7-Dimeth-oxy-2-phenyl-4H-chromen-4-one
(International Union of Crystallography, 2009-02-11) Nallasivam, Angannan; Nethaji, Munirathinam; Vembu, Nagarajan; Ragunathan, Venkatraman; Sulochana, Nagarajan
The asymmetric unit of the title compound, C17H 14O4, contains two independent mol-ecules which differ in the relative orientations of the phenyl rings with repect to the essentially planar [maximum deviations of 0.029 (2) and 0.050 (2) Å in the two mol-ecules] chromene fused-ring system, forming dihedral angles of 10.3 (5) and 30.86 (5)° in the two mol-ecules. The crystal structure is stabilized by weak C - H⋯O and C - -H⋯π inter-actions, and π-π stacking inter-actions.
6,8-Dibromo-5-hydr-oxy-4-oxo-2-phenyl-4H-chromen-7-yl acetate
(International Union of Crystallography, 2009-02-21) Nallasivam, Angannan; Nethaji, Munirathinam; Vembu, Nagarajan; Ragunathan, Venkatraman; Sulochana, Nagarajan
In the title compound, C17H10Br2O5, the chromene ring is almost planar with minimal puckering [total puckering amplitude = 0.067 (4) Å]. The dihedral angle between chromeme ring system and phenyl ring is 3.7 (2)°. The crystal structure is stabilized by intermolecular C - H⋯O inter-actions and an intramolecular O - H⋯O hydrogen bond also occurs.
A combined deep CNN-RNN network for rainfall-runoff modelling in Bardha Watershed, India
(KeAi Communications Co. Ltd., 2024-02-11) Shekar, Padala Raja; Mathew, Aneesh; Yeswanth, P.V.; Deivalakshmi, S
In recent years, there has been a growing interest in using artificial intelligence (AI) for rainfall-runoff modelling, as it has shown promising adaptability in this context. The current study involved the use of six distinct AI models to simulate monthly rainfall-runoff modelling in the Bardha watershed, India. These models included the artificial neural network (ANN), k-nearest neighbour regression model (KNN), extreme gradient boosting (XGBoost) regression model, random forest regression model (RF), convolutional neural network (CNN), and CNN-RNN (convolutional recurrent neural network). The years 2003–2007 are classified as the calibration or training period, while the years 2008–2009 are classified as the validation or testing period for the span of time 2003 to 2009. The available rainfall, maximum and minimum temperatures, and discharge data were collected and utilized in the models. To compare the performance of the models, five criteria were employed: R2, NSE, MAE, RMSE, and PBIAS. The CNN-RNN model simulates the rainfall-runoff model in the Bardha watershed best in both the training and testing periods (training: R2 is 0.99, NSE is 0.99, MAE is 1.76, RMSE is 3.11, and PBIAS is −1.45; testing: R2 is 0.97, NSE is 0.97, MAE is 2.05, RMSE is 3.60, and PBIAS is −3.94). These results demonstrate the superior performance of the CNN-RNN model in simulating monthly rainfall-runoff modelling when compared to the other models used in the study. The findings suggest that the CNN-RNN model could be a valuable tool for various applications related to sustainable water resource management, flood control, and environmental planning.
Adsorptive removal of Pb(II) from aqueous solution using nano-sized hydroxyapatite
(Springer Verlag, 2012-10-11) Ramesh, S.T.; Rameshbabu, N; Gandhimathi, R; Srikanth Kumar, M; Nidheesh P.V.
This study investigated the sorption of Pb(II) in aqueous solution onto hydroxyapatite (HA) surfaces. Batch experiments were carried out using synthetic HA. The effect of contact time, HA dosage, and initial pH on removal efficiency were also investigated. The adsorption equilibrium and kinetics of Pb(II) on this adsorbent were then examined at 25 °C. Kinetic data were analyzed by pseudo first, second, and intra-particle diffusion models. The sorption data were then correlated with the Langmuir, Freundlich, Halsey, and Harkins-Jura adsorption isotherm models. The optimum dose of HA for Pb(II) removal is found to be 0. 12 g/l with the removal efficiency of 97. 3 % at an equilibrium contact time of 1 h. It is found that the adsorption kinetics of the Pb(II) on HA follow the pseudo second-order reaction. All the isotherms fitted well for experimental data. Capacity of HA is found as 357. 14 mg Pb(II)/g of HA. The Pb(II) immobilization mechanism was studied. The results indicated that HA can be used as an effective adsorbent for removal of Pb(II) from aqueous solution. © 2012 The Author(s).
Advancing Agricultural Land Suitability in Urbanized Semi-Arid Environments: Insights from Geospatial and Machine Learning Approaches
(Multidisciplinary Digital Publishing Institute (MDPI), 2024-12-03) Sathiyamurthi, Subbarayan; Subbarayan, Saravanan; Ramya, Madhappan; Sivasakthi, Murugan; Gobi, Rengasamy; Qaysi, Saleh; Praveen Kumar, Sivakumar; Lee, Jinwook; Alarifi, Nassir; Wahba, Mohamed; M. Youssef, Youssef
Rising food demands are increasingly threatened by declining crop yields in urbanizing riverine regions of Southern Asia, exacerbated by erratic weather patterns. Optimizing agricultural land suitability (AgLS) offers a viable solution for sustainable agricultural productivity in such challenging environments. This study integrates remote sensing and field-based geospatial data with five machine learning (ML) algorithms—Naïve Bayes (NB), extra trees classifier (ETC), random forest (RF), K-nearest neighbors (KNN), and support vector machines (SVM)—alongside land-use/land-cover (LULC) considerations in the food-insecure Dharmapuri district, India. A grid searches optimized hyperparameters using factors such as slope, rainfall, temperature, texture, pH, electrical conductivity, organic carbon, available nitrogen, phosphorus, potassium, and calcium carbonate. The tuned ETC model showed the lowest root mean squared error (RMSE = 0.15), outperforming RF (RMSE = 0.18), NB (RMSE = 0.20), SVM (RMSE = 0.22), and KNN (RMSE = 0.23). The AgLS-ETC map identified 29.09% of the area as highly suitable (S1), 19.06% as moderately suitable (S2), 16.11% as marginally suitable (S3), 15.93% as currently unsuitable (N1), and 19.21% as permanently unsuitable (N2). By incorporating Landsat-8 derived LULC data to exclude forests, water bodies, and settlements, these suitability estimates were adjusted to 19.08% (S1), 14.45% (S2), 11.40% (S3), 10.48% (N1), and 9.58% (N2). Focusing on the ETC model, followed by land-use analysis, provides a robust framework for optimizing sustainable agricultural planning, ensuring the protection of ecological and social factors in developing countries. © 2024 by the authors.
Air quality analysis and PM2.5 modelling usingmachine learning techniques: A study of Hyderabad city in India
(Cogent OA, 2023-08-13) Mathew, Aneesh; Gokul, P R; Shekar, Padala Raja; Arunab, K S; Abdo, Hazem Ghassan; Almohamad, Hussein; Al Dughairi, Ahmed Abdullah
The rapid urbanization and industrialization in many parts of the world have made air pollution a global public health problem. A study conducted by the Swiss organization IQAir indicated that 22 of the top 30 most polluted cities in the world are in India. This creates the problem of air pollution, which is very relevant to India as well. Exposure to air pollutants has both acute (short-term) and chronic (long-term) impacts on health. Among the major air pollutants, particulate matter 2.5 (PM2.5) is the most harmful, and its long-term exposure can impair lung functions. Pollutant concentrations vary temporally and are dependent on the local meteorology and emissions at a given geographic location. PM2.5 forecasting models have the potential to develop strategies for evaluating and alerting the public regarding expected hazardous levels of air pollution. Accurate measurement and forecasting of pollutant concentrations are critical for assessing air quality and making informed strategic decisions. Recently, data-driven machine learning algorithms for PM2.5 forecasting have received a lot of attention. In this work, a spatio-temporal analysis of air quality was first performed for Hyderabad, indicating that average PM2.5 concentrations during the winter were 68% higher than those during the summer. Following that, PM2.5 modelling was done using three different techniques: multilinear regression, K-nearest neighbours (KNN), and histogram-based gradient boost (HGBoost). Among these, the HGBoost regression model, which used both pollution and meteorological data as inputs, outperformed the other two techniques. During testing, the model acquired an amazing R2 value of 0.859, suggesting a significant connection with the actual data. Additionally, the model exhibited a minimum Mean Absolute Error (MAE) of 5.717 μg/m3 and a Root Mean Square Error (RMSE) of 7.647 μg/m3, further confirming its accuracy in predicting PM2.5 concentrations. In our investigation, we discovered that the HGBoost3 model beat other PM2.5 modelling models by having the lowest error and the highest R2 value. This study made a substantial addition by incorporating the spatiotemporal relationship between air pollutants and meteorological variables in predicting air quality. This method has the potential to improve the creation of more precise air pollution forecast models.
An assessment of brick masonry strengthening practice by special methods
(Blue Eyes Intelligence Engineering and Sciences Publication, 2019-09-03) Kanchidurai, S; Krishnan, P.A.; Baskar, K
This study aims to identify the best suitable method to enhance strength and the structural performance of masonry. There are different techniques available to strengthen the existing and new masonry structures. This paper deals the metal/mesh embedment in the masonry wall, strengthening by added different polymers and textile strips, masonry grout, engineered cementitious materials (ECC) and interlocking masonry method. The comparison of different unique masonry strengthening methods helps us to provide a better suggestion for construction issues. In contrast to the conventional method, welded wire mesh gives better results than all other ways. Also, embedment of TRM, ECC, FRP, GFRP, CFRP, and interlocking holds an excellent performance in some other aspects. © BEIESP.

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