Galois structure on integral valued polynomials

We characterize finite Galois extensions $K$ of the field of rational numbers in terms of the rings ${\rm Int}_{\mathbb{Q}}(\mathcal O_K)$, recently introduced by Loper and Werner, consisting of those polynomials which have coefficients in $\mathbb{Q}$ and such that $f(\mathcal O_K)$ is contained in $\mathcal O_K$. We also address the problem of constructing a basis for ${\rm Int}_{\mathbb{Q}}(\mathcal O_K)$ as a $\mathbb{Z}$-module.Comment: final version, accepted for publication in J. Number Theory (2016). any comment is welcom

Association between Vascular Endothelial Growth Factor (VEGF) -1154G/A Polymorphism and Endometriosis in North West of Iran

Endometriosis is considered as a multifactorial disease that affects up to 10% of all women of fertile age. Vascular endothelial growth factor (VEGF) is one of the most important activators of angiogenesis. VEGF is known to be a key molecule in the pathogenesis of endometriosis. A great number of studies have referred to genetic polymorphisms as a factor that contributes to the development of endometriosis. The present study was aimed to find out the frequency of the VEGF -1154G/A polymorphism and its relationship with endometriosis risk in Iranian women with endometriosis.This study involved 175 patients with endometriosis and 131 healthy controls. Following extraction of genomic DNA from patients and controls, genotyping of the -1154G/A polymorphism of the VEGF gene were performed by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analysis. Multivariate analysis was used to examine the association between the risk of endometriosis and VEGF -1154G/A polymorphism. There was statistically a significant difference in the frequency of the -1154G/A polymorphism between patients and the controls. The percentage distribution of the three -1154G/A genotypes was (GG 3.4%, GA %46.8%, AA 49.7%) in endometriosis patients.Conclusion: Data supports the hypothesis that angiogenesis is of pivotal importance in the development of endometriosis. Our study indicates that there is significant association between the VEGF gene -1154G/A polymorphism and the risk of endometriosis in North West of Iran

Yield, fruit quality and physiological responses of melon cv. Khatooni under deficit irrigation

To evaluate the effect of water deficit stress on growth, yield, fruit quality and physiological traits of melon cv. Khatooni, field experiments were conducted in split plot randomized complete block design with three replications. In 2014, irrigation treatments consisted of two deficit irrigation regimes, 33% and 66% of ETc (crop evapotranspiration), and 100% ETc as the control (DI33, DI66 and I100). In 2015, irrigation treatments applied were: 40, 70 and 100% ETc (DI40, DI70 and I100). The results showed that plant height and leaf area decreased from treatment I100 to DI40 and DI33. The highest average fruit weigh and yield were obtained from irrigation 100% ETc for both years. The water use efficiency (WUE) significantly increased in response to increase water deficit stress. Deficit irrigation treatments significantly decreased leaf relative water content, vitamin C and fruit firmness, whereas antioxidant enzymes activity, proline and total soluble solid contents increased. These results suggest that the crop is sensitive to water deficits, that moderate water stress (DI70 and DI66) reduced yield by about 28.5-38.2% and severe water stress (DI40 and DI33) had a much more marked effect, reducing yield by 48.1-61.4%

A new practical method to evaluate the Joule-Thomson coefficient for natural gases

© 2017, The Author(s). The Joule–Thomson (JT) phenomenon, the study of fluid temperature changes for a given pressure change at constant enthalpy, has great technological and scientific importance for designing, maintenance and prediction of hydrocarbon production. The phenomenon serves vital role in many facets of hydrocarbon production, especially associated with reservoir management such as interpretation of temperature logs of production and injection well, identification of water and gas entry locations in multilayer production scenarios, modelling of thermal response of hydrocarbon reservoirs and prediction of wellbore flowing temperature profile. The purpose of this study is to develop a new method for the evaluation of JT coefficient, as an essential parameter required to account the Joule–Thomson effects while predicting the flowing temperature profile for gas production wells. To do this, a new correction factor, CNM, has been developed through numerical analysis and proposed a practical method to predict CNM which can simplify the prediction of flowing temperature for gas production wells while accounting the Joule–Thomson effect. The developed correlation and methodology were validated through an exhaustive survey which has been conducted with 20 different gas mixture samples. For each sample, the model has been run for a wide range of temperature and pressure conditions, and the model was rigorously verified by comparison of the results estimated throughout the study with the results obtained from HYSYS and Peng–Robinson equation of state. It is observed that model is very simple and robust yet can accurately predict the Joule–Thomson effect

Maximization of propylene in an industrial FCC unit

YesThe FCC riser cracks gas oil into useful fuels such as gasoline, diesel and some lighter products such as ethylene and propylene, which are major building blocks for the polyethylene and polypropylene production. The production objective of the riser is usually the maximization of gasoline and diesel, but it can also be to maximize propylene. The optimization and parameter estimation of a six-lumped catalytic cracking reaction of gas oil in FCC is carried out to maximize the yield of propylene using an optimisation framework developed in gPROMS software 5.0 by optimizing mass flow rates and temperatures of catalyst and gas oil. The optimal values of 290.8 kg/s mass flow rate of catalyst and 53.4 kg/s mass flow rate of gas oil were obtained as propylene yield is maximized to give 8.95 wt%. When compared with the base case simulation value of 4.59 wt% propylene yield, the maximized propylene yield is increased by 95%

Estudo cinético da formação e dissociação de hidratos de gás.

In 1884, Jacobus Henricus van\'t Hoff and Henry Louis Le Chatelier started the race for understanding chemical kinetics and equilibrium. Consequently, the scientific prowling for coming up direction, stability, and ending point of chemical reactions has not stopped. Equilibrium and kinetic of gas hydrates (also called clathrates), which are crystalline structures formed by light gas molecules (guest) enclosed by water molecules linked by hydrogen bonds, are part of this great race. Accurate knowledge of equilibrium and kinetic of gas hydrates is vital in both flow assurance of transport lines and energy production from the seabed. Traditionally, most of gas hydrates kinetic studies determine the moles of gas consumed from pressure changes measurements when the gas is getting dissolved into water to form the hydrate in an isolated system. So, in this research, a study in a standard reactor has been carried out to evaluate methane hydrate formation and dissociation at 276.2 K and various pressures of 2700, 2900 and 3200 kPa. Among many studied parameters, the second moment of the particle size distribution (µ2(t)) is the key factor to understand the properties of the produced gas hydrate even there is a wide crystal size distribution in practice, since it is related to the kinetic constant. The main objective of this dissertation is to determine methane hydrate µ2(t) based on an analytical model deduced from mass balance. In the construction of the current model, parameters of hydration number, the molar volume of gas hydrates, the initial amount of water contained in the system, and the total number of moles of reacted water are considered. The parameter of hydration number was determined by analytical analysis of quadrupole point while the molar volume of gas hydrates was calculated by using the molecular dynamics (MD) simulation technique. The initial number of moles of reacted water in current research was determined by In-situ Raman spectroscopy and results were validated against the analytical and semi-analytical rigorous model available in the open literature. The total number of moles of reacted water was calculated through a threephase flash. In the last step of the study, High Pressure micro Differential Scanning Calorimetry (HP-µDSC) has been used to better understand phase equilibrium and self-preservation phenomenon, and to determine the acting surface of methane hydrate, which is a crucial parameter in methane hydrate dissociation kinetic. Finally, a new model for methane hydrate dissociation kinetics was proposed and its validity was assessed against experimental data, showing a better agreement when compared to the conventional model approach.Em 1884 iniciou-se a corrida pela compreensão da cinética e do equilíbrio químico, com os trabalhos de Jacobus Henricus van\'t Hoff e Henry Louis Le Chatelier. Desde então, a investigação científica sobre a direção, a estabilidade e o equilíbrio das reações químicas não parou. O estudo do equilíbrio e a cinética de formação dos hidratos (ou clatratos) de gás, cristais contendo moléculas de gás em estruturas formadas por moléculas de água ligadas por ligações de hidrogênio, faz parte dessa grande corrida. O conhecimento preciso do equilíbrio e da cinética de formação dos hidratos de gás é vital para garantir a vazão das linhas de transporte de gás natural. Tradicionalmente, a maioria dos estudos cinéticos analisa a solução e a dissolução indicadas pelas mudanças de pressão em um sistema fechado. Nesta pesquisa, um estudo em reator padrão foi usado para avaliar a formação e dissociação de hidrato de metano a 276,2 K e várias pressões (2700, 2900 e 3200kPa). Entre os muitos parâmetros estudados, o segundo momento da distribuição de tamanho de partícula (µ2(t)) mostrou-se a chave para o entendimento do hidrato de gás produzido. O principal objetivo desta tese, portanto, foi determinar o segundo momento da distribuição de tamanho do hidrato de metano µ2(t) com base em um modelo analítico deduzido do balanço de massa. Na construção do modelo, os parâmetros como o número de hidratação, o volume molar do hidrato de gás, a quantidade inicial de água reagida e a quantidade total de água reagida são encontrados. O parâmetro de número de hidratação foi determinado pela análise analítica do ponto de quadrupolo, enquanto o volume molar de hidratos foi calculado usando a técnica de simulação de dinâmica molecular (MD). O número inicial de moles de água reagida foi determinada por espectroscopia Raman in situ, e os resultados foram validados por modelos rigorosos (analítico e semi-analítico) disponíveis na literatura aberta. O número total de mols de água reagida foi calculado por meio de um flash trifásico. Na última etapa do estudo, micro-calorimetria diferencial de alta pressão (HP-µDSC) foi usada para entender melhor o equilíbrio de fases e determinar a superfície ativa do hidrato de metano, parâmetro crucial na cinética de dissociação dos hidratos. Finalmente, um novo modelo de dissociação de hidrato de metano foi proposto, e sua validade foi verificada, mostrando uma melhor concordância com os dados experimentais quando comparado à abordagem convencional

Natural gas hydrate promotion capabilities of toluene sulfonic acid isomers

The purpose of this study was to investigate the natural gas hydrate promotion capabilities of the hydrotrope Toluene Sulfonic Acid (TSA) isomers as an additive. The capabilities of TSA isomers were measured with different concentrations. The optimum additive concentration for hydrate formation was determined for the given pressure, temperature, mixing condition, and cooling time. The natural gas hydrate promotability of para-TSA was found to be 20% and 35% more than meta-TSA and ortho-TSA respectively at the optimum concentration. Beyond the optimum TSA concentration, the hydrate formation declined as the ice formation reduced the overall gas-to-water volume ratio in the hydrates

Natural gas hydrate promotion capabilities of toluene sulfonic acid isomers

The purpose of this study was to investigate the natural gas hydrate promotion capabilities of the hydrotrope Toluene Sulfonic Acid (TSA) isomers as an additive. The capabilities of TSA isomers were measured with different concentrations. The optimum additive concentration for hydrate formation was determined for the given pressure, temperature, mixing condition, and cooling time. The natural gas hydrate promotability of para-TSA was found to be 20% and 35% more than meta-TSA and ortho-TSA respectively at the optimum concentration. Beyond the optimum TSA concentration, the hydrate formation declined as the ice formation reduced the overall gas-to-water volume ratio in the hydrates