Prediction of partition coefficients for systems of micelles using DFT

[eng] A compound’s solvent−water partition coefficient (log P) measures the equilibrium ratio of the compound’s concentrations in a two-phase system: as two solvents in contact or a system of micelles in an aqueous solution. In this thesis, the partition coefficient of three groups of small compounds (alcohol, ether, and hydrocarbons) in 10 different solvents (benzene, cyclohexane, hexane, n-Octane, toluene, carbon tetrachloride, heptane, trichloroethane, and octanol) was computed used DFT and B3LYP method with 6.31G(d), 6.311+G** and 6.311++G** basis sets. It is obtained that the partition coefficient of alcohol solutes in various solvents using the 6.31G(d) basis set indicates a satisfactory correlation with experimental values. The correlation between the experimental value and the partition coefficient of ether solutes in different solvents using the 6.311++G** basis set shows high agreement. The experimental data displayed a high correlation with the partition coefficient computed for hydrocarbon compounds in various solvents using all three basis sets: 6.31G(d), 6.311+G**, and 6.311++G**. In addition, we have studied the correlation of the experimental partition coefficients in Sodium Dodecyl Sulfate (SDS), Hexadecyltrimethylammonium bromide (HTAB), Sodium cholate (SC), and Lithium perfluoro octane sulfonate (LPFOS) micelles with ab initio calculated partition coefficients in 15 different organic solvents. Specifically, the partition coefficients of a series of 63 molecules in an aqueous system of SDS, SC, HTAB, and LPFOS micelles are correlated with the partition coefficient in heptane/water, cyclohexane/water, n-dodecane/water, pyridine/water, acetic acid/water, octanol/water, acetone/water, 1-propanol/water, 2-propanol/water, methanol/water, formic acid/water, diethyl sulfide/water, decan-1-ol/water, 1-2 ethane diol/water and dimethyl sulfoxide/water systems. All calculations were performed using the Gaussian 16 Quantum Chemistry package. Molecular structures were generated in the more extended conformation using Avogadro, and geometries of all molecules were optimized using Density Functional Theory (DFT) B3LYP and MO6-2X with 6-31++G** basis set by the continuum solvation model based on density (SMD). The obtained results show that calculated partition coefficients in the alcohol/water mixture give the best correlation to predict the experimental partition coefficients in SDS, SC, and LPFOS micelles. With respect to HTAB micelle systems, a new selection of molecules is created, excluding those containing N atoms and Urea atom groups. Interestingly, the partition coefficient of these chosen molecules exhibits a strong correlation with the experimental partition coefficient. Finally, the partition coefficient of flexible molecules was studied by the same protocol for two solvent combinations, octanol/water and cyclohexane/water. The calculated values were compared with the experimental partition coefficients. The average partition coefficient in octanol solvent exhibited a high correlation with the experimental data. However, for the 16 compounds in the cyclohexane solvent, their partition coefficients do not exhibit significant agreement with the experimental partition coefficients.[cat] S'ha desenvolupat una metodologia computacional per calcular el coeficient de partició de diferents tipus de molècules en sistemes micel·lars. En primer lloc, s'ha calculat el coeficient de partició de tres grups de compostos (alcohol, èter i hidrocarburs) utilitzant el mètode DFT amb el funcional B3LYP. S'han obtingut correlacions satisfactòries amb els valors experimentals. En aquesta tesi s'ha desenvolupat un procediment per calcular els coeficients de partició experimentals en micel·les de dodecilsulfat de sodi (SDS), bromur d'hexadeciltrimetilamoni (HTAB), colat de sodi (SC) i perfluorooctanosulfonat de liti (LPFOS). Específicament, els coeficients de partició d'una sèrie de 63 molècules en un sistema aquós de micel·les de SDS, SC, HTAB i LPFOS es correlacionen amb el coeficient de partició en deu barreges aquoses. Els resultats obtinguts mostren que els coeficients de partició calculats a la barreja alcohol/aigua donen la millor correlació per predir els coeficients de partició experimentals en micel·les SDS, SC i LPFOS. Pel que fa als sistemes micelars HTAB, es crea una nova selecció de molècules, excloent-ne aquelles que contenen àtoms de N aromàtics i grups d'urea. És interessant notar que el coeficient de partició d'aquestes molècules triades mostra una forta correlació amb el coeficient de partició experimental. Finalment, es va estudiar el coeficient de partició de molècules flexibles mitjançant el mateix protocol per a dues combinacions de dissolvents, octanol/aigua i ciclohexà/aigua. Els valors calculats es van comparar amb els coeficients de partició experimentals. El coeficient de partició mitjana en dissolvent octanol va mostrar una alta correlació amb les dades experimentals. Tot i això, per als 16 compostos en el dissolvent ciclohexà, els seus coeficients de partició no mostren una concordança significativa amb els coeficients de partició experimental

Prediction of partition coefficients for systems of micelles using DFT

Programa de Doctorat en Química Teòrica i Modelització Computacional[eng] A compound’s solvent−water partition coefficient (log P) measures the equilibrium ratio of the compound’s concentrations in a two-phase system: as two solvents in contact or a system of micelles in an aqueous solution. In this thesis, the partition coefficient of three groups of small compounds (alcohol, ether, and hydrocarbons) in 10 different solvents (benzene, cyclohexane, hexane, n-Octane, toluene, carbon tetrachloride, heptane, trichloroethane, and octanol) was computed used DFT and B3LYP method with 6.31G(d), 6.311+G** and 6.311++G** basis sets. It is obtained that the partition coefficient of alcohol solutes in various solvents using the 6.31G(d) basis set indicates a satisfactory correlation with experimental values. The correlation between the experimental value and the partition coefficient of ether solutes in different solvents using the 6.311++G** basis set shows high agreement. The experimental data displayed a high correlation with the partition coefficient computed for hydrocarbon compounds in various solvents using all three basis sets: 6.31G(d), 6.311+G**, and 6.311++G**. In addition, we have studied the correlation of the experimental partition coefficients in Sodium Dodecyl Sulfate (SDS), Hexadecyltrimethylammonium bromide (HTAB), Sodium cholate (SC), and Lithium perfluoro octane sulfonate (LPFOS) micelles with ab initio calculated partition coefficients in 15 different organic solvents. Specifically, the partition coefficients of a series of 63 molecules in an aqueous system of SDS, SC, HTAB, and LPFOS micelles are correlated with the partition coefficient in heptane/water, cyclohexane/water, n-dodecane/water, pyridine/water, acetic acid/water, octanol/water, acetone/water, 1-propanol/water, 2-propanol/water, methanol/water, formic acid/water, diethyl sulfide/water, decan-1-ol/water, 1-2 ethane diol/water and dimethyl sulfoxide/water systems. All calculations were performed using the Gaussian 16 Quantum Chemistry package. Molecular structures were generated in the more extended conformation using Avogadro, and geometries of all molecules were optimized using Density Functional Theory (DFT) B3LYP and MO6-2X with 6-31++G** basis set by the continuum solvation model based on density (SMD). The obtained results show that calculated partition coefficients in the alcohol/water mixture give the best correlation to predict the experimental partition coefficients in SDS, SC, and LPFOS micelles. With respect to HTAB micelle systems, a new selection of molecules is created, excluding those containing N atoms and Urea atom groups. Interestingly, the partition coefficient of these chosen molecules exhibits a strong correlation with the experimental partition coefficient. Finally, the partition coefficient of flexible molecules was studied by the same protocol for two solvent combinations, octanol/water and cyclohexane/water. The calculated values were compared with the experimental partition coefficients. The average partition coefficient in octanol solvent exhibited a high correlation with the experimental data. However, for the 16 compounds in the cyclohexane solvent, their partition coefficients do not exhibit significant agreement with the experimental partition coefficients.[cat] S'ha desenvolupat una metodologia computacional per calcular el coeficient de partició de diferents tipus de molècules en sistemes micel·lars. En primer lloc, s'ha calculat el coeficient de partició de tres grups de compostos (alcohol, èter i hidrocarburs) utilitzant el mètode DFT amb el funcional B3LYP. S'han obtingut correlacions satisfactòries amb els valors experimentals. En aquesta tesi s'ha desenvolupat un procediment per calcular els coeficients de partició experimentals en micel·les de dodecilsulfat de sodi (SDS), bromur d'hexadeciltrimetilamoni (HTAB), colat de sodi (SC) i perfluorooctanosulfonat de liti (LPFOS). Específicament, els coeficients de partició d'una sèrie de 63 molècules en un sistema aquós de micel·les de SDS, SC, HTAB i LPFOS es correlacionen amb el coeficient de partició en deu barreges aquoses. Els resultats obtinguts mostren que els coeficients de partició calculats a la barreja alcohol/aigua donen la millor correlació per predir els coeficients de partició experimentals en micel·les SDS, SC i LPFOS. Pel que fa als sistemes micelars HTAB, es crea una nova selecció de molècules, excloent-ne aquelles que contenen àtoms de N aromàtics i grups d'urea. És interessant notar que el coeficient de partició d'aquestes molècules triades mostra una forta correlació amb el coeficient de partició experimental. Finalment, es va estudiar el coeficient de partició de molècules flexibles mitjançant el mateix protocol per a dues combinacions de dissolvents, octanol/aigua i ciclohexà/aigua. Els valors calculats es van comparar amb els coeficients de partició experimentals. El coeficient de partició mitjana en dissolvent octanol va mostrar una alta correlació amb les dades experimentals. Tot i això, per als 16 compostos en el dissolvent ciclohexà, els seus coeficients de partició no mostren una concordança significativa amb els coeficients de partició experimental

Socio-economic and Socio-demographic Determinants of Women Empowerment: Empirical Evidence From the Districts of Ghizer and Gilgit, Northern Pakistan

Women empowerment has remained the most deliberate subject and many social scientists have explored this subject in their respective fields. Women empowerment has assorted dimensions, however this study focuses only on two dimensions’ women decision making and women participation. Primarily, this study constructs two indices of women empowerment which are women decision making index and women participation index based on different components computed using principal component analysis. This research uses primary data, where the data is collected from households of the respective regions using two-stage cluster sampling technique. Secondly, this paper scrutinizes the socio-demographic and economic causes of women empowerment in Gilgit and Ghizer districts of Gilgit-Baltistan using structural equation model. The scores of women empowerment indexes indicate that in terms of decision making, women of Ghizer district are more empowered as compared to Gilgit district whereas in terms of women participation women of Gilgit are more empowered. Amongst the socio-economic and demographic variables, education level shows significant and positive association with both indexes of empowerment. Correspondingly, standard of living of the household demonstrates a significant relationship with women decision making showing that the better the standard of living the more empowered will be the women. Moreover, household size shows a positive and significant relationship with women participation, having more people at home can augment the empowerment of women in terms of participation whereas asset index shows a negative association with women participation

Rural Tourism, Income and Rapid Urbanization: Exploring the Nexus Using A MultiDisciplinary Approach for Hunza, Pakistan

Serving the purpose of an early warning, this paper provides a multi-disciplinary analysis of how thechanging dynamics of tourist arrivals can lead to rapid and unplanned urbanization. The improvements in infrastructureand communication systems under the aegis of China-Pakistan Economic Corridor (CPEC) in Gilgit-Baltistan have ledto exponential increase in tourists arrival in recent years. Does this increase lead to increase in incomes and spurring anunplanned and rapid urbanization? Hunza district is taken as a case study on the basis of evidence suggesting thataround 70 percent of total tourists Gilgit-Baltistan. To explore the relationship between tourists arrival and rapidurbanization, three types of data were used: survey data collected via questionnaires, secondary data from governmentsources, and Google images, Landsat-7 and Landsat-8 from remotely sensed data. Using cross-tabulations, this studysuggests that tourists arrival led to increase in incomes, which were then spent on building commercial infrastructure.To cross check these results, land use land change study using GIS mapping was conducted for the last ten yearsperiod. It shows that rapid and unplanned urbanization has profound social and environmental implications for Hunza,if not managed properly and timely

Experimental and Numerical Study of a Submarine and Propeller Behaviors in Submergence and Surface Conditions

In this paper, hull/propeller interaction of a submarine model which has a realistic geometry, in submergence and surface conditions has been studied. For this purpose, the computational fluid dynamics (CFD) method has been used to solve the viscous, incompressible, two phase flow field (in surface condition) around a model of the propeller and submarine hull with and without propeller. The rotation of the propeller has been modeled using the sliding mesh technique. For turbulent flow modeling and free surface simulation, the k-ω SST model and the volume of fluid method (VOF) have been used, respectively. Experimental data obtained from test conducted by the authors in M.U.T. towing tank have been used to validate the numerical scheme. Comparing numerical and experimental results shows good agreement. The experimental and numerical results show that operation of the propeller near water surface reduces the thrust coefficient of the propeller comparing to open water condition, so that according to experimental results the maximum relative reduction of the thrust coefficient is 8.95%. In addition, the results indicated the amount of hull resistance coefficient in surface condition is more than submergence condition. According to the thrust reduction and wake factors obtained from the numerical results, it is known that their values in surface condition are less than submergence condition. This research can be used for more realistic investigation of hull/propeller interaction and thus, more accurate powering performance prediction of submarines

The Response of Land Surface Temperature to the Changing Land-Use Land-Cover in a Mountainous Landscape under the Influence of Urbanization: Gilgit City as a case study in the Hindu Kush Himalayan Region of Pakistan

With growing urbanization in mountainous landscapes, the built-up areas dominate other land use classesresulting in increased land surface temperature (LST). Gilgit city in northern Pakistan has witnessed tremendousurban growth in the recent past decades. It is anticipated that this growth will exponentially increase in the nearfuture because of the China-Pakistan Economic Corridor (CPEC) initiatives, as this city happens to be thecommercial hub of the northern region of Pakistan. The objective of present study is to explore the influence ofland use and land cover variations on LST and to evaluate the relationship between LST with normalizeddifference vegetation index (NDVI), normalized difference water index (NDWI), and normalized difference built -up index (NDBI) values. This study is carried out on data from Google earth and three Landsat images (Landsat 5-TM, Landsat 7-ETM, and Landsat OLI_TIRS-8) during the period from 1992, 2004 and 2016. Land use/coverclasses are determined through supervised classification and LST maps are created using the Mono -windowalgorithm. The accuracy assessment of land use/cover classes is carried out comparing Google Earth digitizedvector for the periods of 2004 and 2016 with Landsat classified images. Further, NDVI, NDBI, and NDWI mapsare computed from images for years 1992, 2004, and 2016. The relationships of LST with NDVI, NDBI, andNDWI are computed using Linear Regression analysis. The results reveal that the variations in land use and landcover play a substantial role in LST variability. The maximum temperatures are connected with built -up areas andbarren land, ranging from 48.4°C, 50.7°C, 51.6°C, in 1992, 2004, and 2016, respectively. Inversely, minimumtemperatures are linked to forests and water bodies, ranging from 15.1°C, 16°C, 21.6°C, in 1992, 2004, and 2016respectively. This paper also results that NDBI correlates positively with high temperatures, whereas NDVI andNDWI associate negatively with lesser temperatures. The study will support to policymakers and urban planners tostrategize the initiatives for eco-friendly and climate-resilient urban development in fragile mountainouslandscapes

Motion Of Pigments In Thin Paint Films

Paper presented at 2018 Canadian Society of Mechanical Engineers International Congress, 27-30 May 2018.When thin paint layers are exposed to heat, evaporation of the solvent begins, and significant movement within the paint film occur, causing temperature and concentration gradients. A clear coat paint was used, which had a density of 988 kg/mᶟ, viscosity of 240 cP and a surface tension of 26 mN/m and was mixed with spherical solid blue particles with a mean diameter 26 μm were added to the paint at 2% concentration of the total mass. A knife edge was used to coat stainless steel substrates at different thicknesses and placed in a convection oven at 121⁰C for 30 minutes. Images of the samples during the curing process were taken, showing how the pigments moved from low to high surface tension areas. Colour measurements were taken to show that increasing the thickness of the same paint significantly decreases the lightness value

Impact of Transport Cost and Travel Time on Trade under China-Pakistan Economic Corridor (CPEC)

China is the second biggest economy in the world and almost 40% of its trade in 2016 is transported through the South China Sea. China needs a small, secure, and low-cost path to trade with Europe and the Middle East and China-Pakistan Economic Corridor (CPEC) is a feasible solution to this requirement. This research analyzes the effect of CPEC on trade in terms of transport cost and travel time. In addition, the study compares the existing routes and the new CPEC route. The research methodology consists of qualitative and descriptive statistical methods. The variables (transport cost and travel time) are calculated and compared for both the existing route and new CPEC route. The results show that transport cost for 40-foot container between Kashgar and destination ports in the Middle East is decreased by about $1450 dollars and for destination ports in Europe is decreased by$1350 dollars. Additionally, travel time is decreased by 21 to 24 days for destination ports in the Middle East and 21 days for destination ports in Europe. The distance from Kashgar to destination ports in the Middle East and Europe is decreased by 11,000 to 13,000 km. Document type: Articl

Prediction of Partition Coefficients in SDS Micelles by DFT Calculations

A computational methodology using Density-Functional Theory (DFT) calculations was developed to determine the partition coefficient of a compound in a solution of Sodium Dodecyl Sulfate (SDS) micelles. Different sets of DFT calculations were used to predict the free energy of a set of 63 molecules in 15 different solvents with the purpose of identifying the solvents with similar physicochemical characteristics to the studied micelles. Experimental partition coefficients were obtained from Micellar Electrokinetic Chromatography (MEKC) measurements. The experimental partition coefficient of these molecules was compared with the predicted partition coefficient in heptane/water, cyclohexane/water, N-dodecane/water, pyridine/water, acetic acid/water, decan-1- ol/water, octanol/water, propan-2-ol/water, acetone/water, propan-1-ol/water, methanol/water, 1,2-ethane diol/water, dimethyl sulfoxide/water, formic acid/water, and diethyl sulphide/water systems. It is observed that the combination of pronan-1-ol/water solvent was the most appropriated to estimate the partition coefficient for SDS micelles. This approach allowed us to estimate the partition coefficient orders of magnitude faster than the classical molecular dynamics simulations. The DFT calculations were carried out with the well-known exchange correlation functional B3LYP and with the global hybrid functional M06-2X from the Minnesota functionals with 6-31++G ** basis set. The effect of solvation was considered by the continuum model based on density (SMD). The proposed workflow for the prediction rate of the participation coefficient unveiled the symmetric balance between the experimental data and the computational methods