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New approaches to identification and characterization of tioconazole in raw material and in pharmaceutical dosage forms

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Journal of Pharmaceutical Analysis 2019年第1期9卷 40-48页

作者： Natalia L.Calvo Vera A.Alvarez María C.Lamas Darío Leonardi Instituto de Química Rosario (IQUIR CONICET-UNR) área Análisis de Medicamentos Facultad de Ciencias Bioquímicas y Farmacéuticas Universidad Nacional de Rosario Grupo de Materiales Compuestos termoplásticos (CoMP) Instituto de Investigaciones de Cienciay Tecnología de Materiales (INTEMA CONICET-UNMdP) área técnica farmacéutica Facultad de Ciencias Bioquímicas y Farmacéuticas Universidad Nacional de Rosario

tioconazole(tCZ), a broad-spectrum antifungal agent, has significant activity against Candida albicans and other Candida species, and therefore, it is indicated for the topical treatment of superficial *** main goal of this work is to report an exhaustive identification and characterization procedure to improve and facilitate the online quality control and continuous process monitoring of tCZ in bulk material and loaded in two different dosage forms: ovules and nail lacquer. the methodologies were based on thermal(differential scanning calorimetry(DSC), melting point, and thermogravimetry(tG)),spectroscopic(ultraviolet(UV), Raman, near infrared(NIR), infrared spectroscopy coupled to attenuated total reflectance(FtIR-AtR), and nuclear magnetic resonance(NMR)), microscopic and X-ray diffraction(XRD). the tCZ bulk powder showed a high crystallinity, as observed by XRD, with a particles size distribution(3–95 mm) resolved by microscopic measurements. tCZ melting point(82.8 °C) and a degradation peak centered at 297.8 °C were obtained by DSC and DtG, respectively. An unambiguous structure elucidation of tCZ was obtained by mono-and two-dimensional1 H and13 C NMR spectral data analysis. the FtIR-AtR, Raman and NIR spectra of both the raw material and the commercial products were analyzed and their characteristic bands were tabulated. the best methods for tCZ identification in ovules were DSC, tG, XRD, NIR and Raman, while NIR and FtIR-AtR were the most appropriate techniques to analyze it in the nail lacquer. DSC, tG, DRX, Raman, FtIR-AtR and NIR spectroscopy are effective techniques to be used in online process analysis, because they do not require sample preparation, and they are considerably sensitive to analyze complex samples.

关键词： tioconazole Identification Characterization Pharmaceutical dosage forms Spectroscopic methods

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Influence of parameters on the microstructure of a duplex stainless steel joint welded by a GMAW welding process

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Progress in Natural Science:Materials International 2022年第4期32卷 415-423页

作者： Sandra Chacón-Fernández Antonio Portolés García Gerardo Romaní Labanda Universidad Politécnica de Madrid Escuela Técnica Superior de Ingenieros Industriales UPM

Duplex stainless steels（DSSs） are widely used in industry for their desirable properties. Any fusion welding technique modifies the microstructure and, consequently, the properties of the material. this paper presents a parametric study of the variables that determine the energy contribution（current, voltage and welding speed） and the structural modifications produced during gas metal arc welding. the analysis comprises metallographic study,phase balance, dimensioning of the weld beads and tensile and hardness tests. the influence of the variables studied on the thermal cycles obtained（temperatures reached and cooling rate） was determined by using a finite element model. the results showed that, in addition to the indicated parameters, the parameter power transfer per volume（W/m3） and the geometry in the bead must be controlled due to their influence on the heat flow distribution and phase balance.

关键词： Welding Heat input GMAW Duplex stainless steels (DSS) Finite element model (FEM)

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Revisiting the analytical solutions for ultimate bearing capacity of pile embedded in rocks

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第6期15卷 1506-1519页

作者： A.Picardo M.A.Millán R.Galindo A.Alencar Escuela técnica Superior de Arquitectura Universidad Politécnica de MadridMadrid28040Spain Escuela técnica Superior de Ingenieros de Caminos Canales y Puertos de MadridUniversidad Politécnica de MadridMadrid28040Spain

this paper investigates the validity and shortcomings of the existing analytical solution for the ultimate bearing capacity of a pile embedded in a rock mass using the modified HoekeBrown failure *** this criterion is considered a reference value for empirical and numerical calculations,some limitations of its basic simplifications have not been clarified *** research compares the analytical results obtained from the novel discontinuity layout optimization(DLO)method and the numerical solutions from the finite difference method(FDM).the limitations of the analytical solution are considered by comparing different DLO failure modes,thus allowing for the first time a critical evaluation of its scope and conditioning for *** of up to 40%in the bearing capacity and unrealistic failure modes are the main issues in the analytical *** main aspects of the DLO method are also analyzed with an emphasis on the linearization of the rock failure criterion and the accuracy resulting from the discretization *** analysis demonstrates DLO as a very efficient and accurate tool to address the pile tip bearing capacity,presenting considerable advantages over other methods.

关键词： Discontinuity layout optimization(DLO) Analytical solution Bearing capacity Deep foundations HoekeBrown failure criterion Finite difference method(FDM)

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Structure, Electronic Properties and Chemical Bonding in Bis(1H-imidazolium-κN^3)silver(Ⅰ) Nitrate from Periodic DFt Computations

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Chinese Journal of Structural Chemistry 2013年第8期32卷 1143-1152页

作者： Arvids Stashansa Soraya Jácome Grupo de Fisicoquímica de Materiales Universidad Técnica Particular de Loja Escuela de Ingeniería Química Universidad Técnica Particular de Loja

Using the first-principles density functional theory calculations within the genera- lized gradient approximation we study the bis（1H-imidazolium-kN3）silver（I） nitrate molecular crystal. A number of different exchange-correlation functionals are considered for a possible treatment of the system. Perdew-Burke-Emzerhof （PBE） GGA exchange-correlation ftmctionals are found to be adequate for our system. the obtained results show that it is possible to reproduce very well the geometry of at least some molecular crystals if computational parameters are chosen adequately. In addition to the reproducing crystal structure of the bis（1H-imidazolium-kN3）silver（I） nitrate in close agreement with the available experimental data, the present work reports analysis on the chemical bonding in the material and gives total and partial density of states of this system.

关键词： crystal structure electronic properties chemicalbonding density functional theory

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Nonlocal material properties of single-walled carbon nanotubes

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International Journal of Smart and Nano Materials 2012年第2期3卷 141-151页

作者： J.V.Araújo dos Santos C.M.Mota Soares IDMEC Instituto Superior TécnicoUniversidade Técnica de Lisboa1049-001 LisboaPortugal

Natural frequencies of single-walled carbon nanotubes(SWCNts)obtained using a model based on Eringen’s nonlocal continuum mechanics and the timoshenko beam theory are compared with those obtained by molecular dynamics *** goal was to determine the values of the material constant,considered here as a nonlocal property,as a function of the length and the diameter of *** present approach has the advantage of eliminating the SWCNt thickness from the computations.A sensitivity analysis of natural frequencies to changes in the nonlocal material constant is also carried out and it shows that the influence of the nonlocal effects decreases with an increase in the SWCNt *** matching of natural frequencies shows that the nonlocal material constant varies with the natural frequency and the SWCNt length and diameter.

关键词： nonlocal mechanics molecular dynamics simulation single-walled carbon nanotube timoshenko beam

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A Protocol for Fractal Studies on Porosity of Porous Media: High Quality Soil Porosity Images

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Journal of Earth Science 2017年第5期28卷 888-896页

作者： Carlos García-Gutiérrez Fernando San José Martínez J.Caniego Dpto.Matemática Aplicada E.T.S.I.Navales Universidad Politécnica de Madrid Dpto.Matemática Aplicada E.T.S.I.Agrónomos Universidad Politécnica de Madrid

A protocol for obtaining digital images from natural porous media with a wide range of pore sizes, intended for fractal studies of the porosity, is proposed. Soil porosity is used as para- digm of complex natural porous media in this study. the use of several imaging devices and fluores- cent compounds to enhance the contrast between the solid and the pore phase is tested. Finally a protocol is reached using a photo camera and a confocal microscope. It is the first time that confocal microscopy is used for this purpose. Artificial porous images are created through random Sierpinski carpet fractals and the statistical information of real soil images. these ground truth images are used in an objective comparison of automatic segmentation algorithms for the obtained images. A statistical classification on the performance of several automatic segmentation algorithms for this tv^e of images is reached.

关键词： porous media micromorphology image segmentation confocal microscope fractal,porosity photography.

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Optimal Design of Hybrid Microgrid in Isolated Communities of Ecuador

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Journal of Modern Power Systems and Clean Energy 2024年第2期12卷 488-499页

作者： Luis A.Pesantes Ruben Hidalgo-León Johnny Rengifo Miguel torres Jorge Aragundi JoséCordova-Garcia Luis F.Ugarte Facultad de Ingeniería en Electricidad y Computación of Escuela Superior Politécnica del Litoral(ESPOL)University GuayaquilEcuador Department of Electrical Engineering at Universidad técnica Federico Santa María SantiagoChile IEEE

In rural territories, the communities use energy sources based on fossil fuels to supply themselves with electricity, which may address two main problems: greenhouse gas emissions and high fuel prices. Hence, there is an opportunity to include renewable resources in the energy mix. this paper develops an optimization model to determine the optimal sizing, the total annual investment cost in renewable generation, and other operating costs of the components of a hybrid microgrid. By running a k-means clustering algorithm on a meteorological dataset of the community under study, the hourly representative values become input parameters in the proposed optimization model. the method for the optimal design of hybrid microgrid is analyzed in six operating scenarios considering:(1) 24-hour continuous power supply;(2) load shedding percentage;(3) diesel power generator(genset) curtailment;(4) the worst meteorological conditions;(5) the use of renewable energy sources including battery energy storage systems(BESSs);and(6) the use of genset. A mathematical programming language(AMPL) tool is used to find solutions of the proposed optimization model. Results show that the total costs of microgrid in the scenarios that cover 100% of the load demand(without considering the scenario with 100% renewables) increase by over 16% compared with the scenario with genset operation limitation. For the designs with power supply restrictions, the total cost of microgrid in the scenario with load shedding is reduced by over 27% compared with that without load shedding.

关键词： Battery energy storage system(BESS) isolated community microgrid renewable energy optimization

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Liouvillian and Analytic Integrability of the Quadratic Vector Fields Having an Invariant Ellipse

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Acta Mathematica Sinica,English Series 2014年第3期30卷 453-466页

作者： Jaume LLIBRE Claudia VALLS Departament de Matemàtiques Universitat Autònoma de Barcelona Departamento de Matemtica Instituto Superior TcnicoUniversidade Tcnica de Lisboa

We characterize the Liouvillian and analytic integrability of the quadratic polynomial vector fields in R2 having an invariant *** precisely,a quadratic system having an invariant ellipse can be written into the form x=x2＋y2-1＋y（ax＋by＋c）,y=x（ax＋by＋c）,and the ellipse becomes x2＋y2=*** prove that（i） this quadratic system is analytic integrable if and only if a=0;（ii） if x2＋y2=1 is a periodic orbit,then this quadratic system is Liouvillian integrable if and only if x2＋y2=1 is not a limit cycle;and（iii） if x2＋y2=1 is not a periodic orbit,then this quadratic system is Liouvilian integrable if and only if a=0.

关键词： Liouvillian integrability quadratic planar polynomial vector fields invariant ellipse

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Impact of radiative cooling on the energy performance of courtyards in Mediterranean climate

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Building Simulation 2024年第9期17卷 1491-1513页

作者： Carlos-Antonio Domínguez-torres Antonio Domínguez-Delgado Escuela técnica Superior de Arquitectura Universidad de SevillaAv.de Reina Mercedes241012 SevillaSpain Department of Applied Mathematics 1 Escuela Técnica Superior de ArquitecturaUniversidad de SevillaAv.de Reina Mercedes241012 SevillaSpain

Radiative cooling has proven to be a useful tool to address the problems of lack of comfort and excessive energy consumption in situations of high temperatures,overheating and heat ***,incorporating courtyards in warm climate zones has been found to be highly beneficial in addressing similar ***,there is interest in analyzing the combined effects of both:radiative cooling and *** paper presents an analysis of the impact of the application of radiative cooling on a courtyard using a comprehensive simulation approach that includes a CFD model for the thermodynamic airflow in the adjacent roofs and inside the courtyard,equations for the transient heat conduction through roofs,walls and courtyard slabs,and a hybrid raytracing-radiosity model for the evaluation of the solar radiation reaching the building surfaces and its reflections,both of specular and diffuse origin,and for the calculation of the thermal radiation exchange,especially with the *** results show that in the hot season,the courtyard with radiative cooling always provides lower temperatures than the initial courtyard does,with a temperature range of 18.33℃to 33.78℃,compared to a range of 19.32℃to 38.00℃in the initial courtyard,and producing a greater difference with outdoor temperatures that can reach 12℃versus 8℃for the reference *** addition,it was found that the courtyard with radiative cooling is able to significantly reduce the observed nighttime overheating by providing lower temperatures than the outdoor temperatures in the 50%of the nights *** was also found that the thermal loads to achieve indoor thermal comfort in the spaces adjacent to the courtyard were reduced by 63.46%to 69.85%.

关键词： radiative cooling passive cooling CFD three-dimensional modeling energy saving thermal comfort

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INVERSE COEFFICIENt PROBLEMS FOR PARABOLIC HEMIVARIAtIONAL INEQUALItIES

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Acta Mathematica Scientia 2011年第4期31卷 1318-1326页

作者：刘振海 I. Szntó Faculty of Mathematics and Computer Science Guangxi University for Nationalities Departamento de Matemtica Universidad Tcnica Federico Santa María

this paper is devoted to the class of inverse problems for a nonlinear parabolic hemivariational inequality. the unknown coefficient of the operator depends on the gradient of the solution and belongs to a set of admissible coefficients. It is proved that the convergence of solutions for the corresponding direct problems continuously depends on the coefficient convergence. Based on this result the existence of a quasisolution of the inverse problem is obtained.

关键词： parabolic hemivariational inequalities inverse coefficient problems existence of quasisolutions

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