检索结果-南通市图书馆

A Data Security Framework for Cloud Computing Services

在线全文

学校读者我要写书评

暂无评论

Computer Systems Science & Engineering 2021年第5期37卷 203-218页

作者： luis-Eduardo Bautista-Villalpando Alain Abran Department of Electronic Systems Autonomous University of AguascalientesAguascalientes20131Mexico Department of Software Engineering and Information Technology ETSUniversity of QuebecMontrealH3C 1K3Canada

Cyberattacks are difficult to prevent because the targeted companies and organizations are often relying on new and fundamentally insecure cloudbased technologies,such as the Internet of *** increasing industry adoption and migration of traditional computing services to the cloud,one of the main challenges in cybersecurity is to provide mechanisms to secure these *** work proposes a Data Security Framework for cloud computing services(CCS)that evaluates and improves CCS data security from a software engineering perspective by evaluating the levels of security within the cloud computing paradigm using engineering methods and techniques applied to *** framework is developed by means of a methodology based on a heuristic theory that incorporates knowledge generated by existing works as well as the experience of their *** paper presents the design details of the framework,which consists of three stages:identification of data security requirements,management of data security risks and evaluation of data security performance in CCS.

关键词： Cloud computing services computer security data security data security requirements data risk data security measurement

Use of two-surfactants mixtures to attain specific HLB values for assisted TPH-diesel biodegradation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2004年第6期16卷 950-956页

作者： luis G. Torres Neftalí Rojas Rosario Iturbe Instituto de Ingeniería Universidad Nacional Autó noma de México Coordinación de Ingeniería Ambiental Grupo Saneamiento de Suelos y Acuíferos Apartado Postal 70-472 Coyoacán 04510 México D.F. Mexico

In a surfactant assisted biodegradation process, the choice of surfactant(s) is of crucial importance. The question is: does the type of surfactant(i.e. chemical family) affect the biodegradation process at fixed hidrophillic-lypofillic balance(HLB) values? Microcosm assessments were developed using contaminated soil, with around of 5000 mg/kg of hydrocarbons as TPH-diesel. Mixtures of three nonionic surfactants were employed to get a wide range of specific HLB values. Tween20 and Span20 were mixed in the appropriate proportions to get HLB values between 8.6 and 16.7. Tween/Span60 mixtures reached HLB values between 4.7 and 14.9. Finally, Tween/Span80 combinations yielded HLB values between 4.3 and 15. TPH-diesel biodegradation was measured at the beginning, and after 8 weeks, as well as the FCU/gr soil, as a measure of microorganisms′ development during the biodegradation period. A second aim of this work was to assess the use of guar gum as a biodegradation enhancer instead of synthetic products. The conclusions of this work are that surfactant chemical family, and not only the HLB value clearly affects the assisted biodegradation rate. Surfactant's synergism was clearly observed. Regarding the use of guar gum, no biodegradation enhancement was observed for the three assessed concentrations, i.e., 2, 20, and 200 mg/kg, respectively. On the contrary, TPH-diesel removal was lower as the gum concentration increased. It is quite possible that guar gum was used as a microbial substrate.

关键词： aged soils enhanced bioremediation HLB mixtures Tween Span surfactants

Strength and stiffness reduction factors for infilled frames with openings

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2014年第3期13卷 437-454页

作者： luis D.Decanini Laura Liberatore Fabrizio Mollaioli Department of Structural Engineering and Geothecnics "Sapienza" University of Rome

Framed structures are usually infilled with masonry walls. They may cause a significant increase in both stiffness and strength, reducing the deformation demand and increasing the energy dissipation capacity of the system. On the other hand, irregular arrangements of the masonry panels may lead to the concentration of damage in some regions, with negative effects; for example soft story mechanisms and shear failures in short columns. Therefore, the presence ofinfill walls should not be neglected, especially in regions of moderate and high seismicity. To this aim, simple models are available for solid infills walls, such as the diagonal no-tension strut model, while infilled frames with openings have not been adequately investigated. In this study, the effect of openings on the strength and stiffness of infilled frames is investigated by means of about 150 experimental and numerical tests. The main parameters involved are identified and a simple model to take into account the openings in the infills is developed and compared with other models proposed by different researchers. The model, which is based on the use of strength and stiffness reduction factors, takes into account the opening dimensions and presence of reinforcing elements around the opening. An example of an application of the proposed reduction factors is also presented.

关键词： infilled frames openings strength stiffness reduction factor

Cell bioenergetics:Simple logics,complex solut

在线全文

学校读者我要写书评

暂无评论

BIOCELL 2022年第10期46卷 2217-2220页

作者： luis S.MAYORGA Instituto de Histología y Embriología de Mendoza(IHEM Universidad Nacional de CuyoCONICET)Facultad de Ciencias Exactas y NaturalesMendoza5500Argentina

Cells are open systems that exchange energy and molecules with their *** any material system,they perform all the complex activities required for homeostasis and reproduction,obeying the thermodynamic *** viewpoint will argue that the basic logic governing the energy flux required to preserve cell organization and function is simple:to decrease the activation energy(Ea)of specific *** none of the possible chemical reactions and energy transformations inside a cell occur at a measurable speed at room or body *** or other macromolecular structures speed up particular transformations by decreasing the corresponding energetic ***,to maintain the systems in a homeostatic state,capable of sophisticated functions based on this simple strategy requires an inconceivably complex *** conclusion will point to the challenging and intricate problems that cells have solved to carve the highly regulated channel through which the energy flows,fueling the work of these nanoscale machines.

关键词： Thermodynamics Cellular logics Self-organization Complexity

Proline and Oxidative Metabolism in Young Pecan Trees Associated with Sulphate Accumulation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Phyton-International Journal of Experimental Botany 2022年第6期91卷 1141-1152页

作者： Dalila Jacqueline Escudero-Almanza Oscar Cruz-alvarez Ofelia Adriana Hernández-Rodríguez Juan luis Jacobo-Cuellar Esteban Sánchez-Chávez Pablo Preciado-Rángel Dámaris Leopoldina Ojeda-Barrios Facultad de Ciencias Agrotecnológicas Universidad Autónoma de ChihuahuaChihuahua31350México Centro de Investigación en Alimentación y Desarrollo A.C.Delicias33088México InstitutoTecnologico Nacional de México-Instituto Tecnológico de Torreón Coahuila27170México

Pecan[Carya illinoinensis(Wangenh.)***.]is a deciduous tree whose fruits(nuts)are of high economic value and offer excellent nutritional ***,soils high in sulphates can limit its growth and *** with 5-year-old trees of‘Western Schley’pecan grown in soils high in sulphates,the levels of proline and oxidative metabolism were recorded in the *** showed that different levels of visible leaflet damage(‘sufficiency’,‘low’,‘moderate’or‘severe’)were associated with different levels of leaflet sulphates(mg kg^(−1)):‘sufficiency’(≤40),‘low’(41–60),‘moderate’(61–80)and‘severe’(80–100).‘Severe’sulphate damage was associated with significant reductions in chlorophyll(TChl)(17.04μg g^(−1)),relative water content(RWC)(50%)and leaf area(LA),and with increases in the concentrations of total carotenoids(TC)and proline(Prl).Increases were also observed in the activities of the oxidative metabolism enzymes:superoxide dismutase(SOD)(1.82 units min^(−1) g^(−1)),catalase(CAT)(2.86μmol H_(2)O_(2) min^(−1) g^(−1))and antioxidant capacity(AC)(87%DPPH inhibition).However,guaiacol peroxidase(GP)showed a reduction(2.97 nmol GSH min^(−1) g^(−1)).An inverse relationship was found between the sulphate concentration in the leaflets with respect to the evaluated parameters of TChl,TC,RWC,LA,AC,and *** synthesis and antioxidant enzymatic activity indicate salt stress in pecan leaflets in orchards irrigated with deep-well water high in sulphates.

关键词： Carya illinoinensis catalase guaiacol peroxidase salt stress photosynthetic pigments superoxide dismutase

Higher cardiovascular risk scores and liver fibrosis risk estimated by biomarkers in patients with metabolic-dysfunction-associated fatty liver disease

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Hepatology 2022年第8期14卷 1633-1642页

作者： Giovanni Alejandro Salgado alvarez Samanta Mayanin Pinto Galvez Uriel Garcia Mora Ana Delfina Cano Contreras Cristina Durán Rosas Bryan Adrián Priego-Parra Arturo Triana Romero Mercedes Amieva Balmori Federico Roesch Dietlen Sophia Eugenia Martinez Vazquez Ines Osvely Mendez Guerrero luis Alberto Chi-Cervera Raúl Bernal Reyes Leonardo Alberto Martinez Roriguez Maria Eugenia icaza Chavez Jose Maria Remes Troche Instituto de Investigaciones Médico-biologicas Universidad VeracruzanaVeracruz 91700VeracruzMexico Department of Gastroenterología Instituto Nacional de Ciencias Médicas y Nutrición Salvador ZubiránMéxico 14080MéxicoMexico Clínica de Especialidades Gastrointestinales y Hepáticas Hospital Star MedicaMerida 97133YucatanMexico Department of Gastroenterologia Sociedad Española de BeneficenciaPachuca 42000HidalgoMexico Department of Gastroenterologia Clínica de Rehabilitación Metabólica Digestiva y HepáticaMexico 14080MexicoMexico Department of Gastroenterologia Hospital Star Médica de MéridaMerida 97133YucatanMexico

BACKGROUND The definition of metabolic-dysfunction-associated fatty liver disease(MAFLD)allows identification of metabolically complicated *** risk scores are related to cardiovascular risk(CVR)scores and could be useful for the identification of patients at risk of systemic *** To evaluate the relationship between MAFLD and CVR using the Framingham risk score in a group of Mexican *** Cross-sectional,observational and descriptive study carried out in a cohort of 585 volunteers in the state of Veracruz with MAFLD *** risk of liver fibrosis was calculated with aspartate aminotransferase-to-platelet ratio index,nonalcoholic fatty liver disease score and fibrosis-4,as well as with transient hepatic elastography with Fibroscan~?.The CVR was determined by the Framingham *** One hundred and twenty-five participants(21.4%)with MAFLD criteria were evaluated,average age 54.4 years,63.2%were women,body mass index 32.3 kg/m~*** Framingham CVR was high in 43 patients(33.9%).Transient elastography was performed in 55.2%of volunteers;39.1%with high CVR and predominance in advanced fibrosis(F3–F4).The logistic regression analysis showed that liver fibrosis,diabetes and hypertension independently increased *** One of every three patients with MAFLD had a high CVR,and in those with high fibrosis risk,the CVR risk was even greater.

关键词： Fatty liver Cardiovascular risk Hepatic steatosis Fibrosis Liver disease

Less is more:dimensionality reduction as a general strategy for more precise luminescence thermometry

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Light(Science & Applications) 2022年第9期11卷 2127-2139页

作者： ERVING XIMENDES RICCARDO MARIN luis DIAS CARLOS DANIEL JAQUE NanoBIG Departamento de Fisica de MaterialesFacultad de CienciasUniversidad Autónoma de MadridC/Francisco Tomás y Valiente 7Madrid 28049Spain NanoBIG Instituto Ramón y Cajal de Investigación Sanitaria(IRYCIS)Ctra.Colmenar km.9.100Madrid 28034Spain Phantom-g CICECO-Aveiro Institute of MaterialsDepartment of PhysicsUniversity of AveiroAveiro 3810-193Portugal

Thermal resolution(also referred to as temperature uncertainty)establishes the minimum discernible temperature change sensed by luminescent thermometers and is a key figure of merit to rank *** has been done to minimize its value via probe optimization and correction of readout artifacts,but little effort was put into a better exploitation of calibration *** this context,this work aims at providing a new perspective on the definition of luminescence-based thermometric parameters using dimensionality reduction techniques that emerged in the last *** application of linear(Principal Component Analysis)and non-linear(t-distributed Stochastic Neighbor Embedding)transformations to the calibration datasets obtained from rare-earth nanoparticles and semiconductor nanocrystals resulted in an improvement in thermal resolution compared to the more classical intensity-based and ratiometric ***,in turn,enabled precise monitoring of temperature changes smaller than 0.1℃.The methods here presented allow choosing superior thermometric parameters compared to the more classical ones,pushing the performance of luminescent thermometers close to the experimentally achievable limits.

关键词： precise dimensionality luminescence

Optimal Design of Hybrid Microgrid in Isolated Communities of Ecuador

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

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

Symmetrization for Fractional Elliptic and Parabolic Equations and an Isoperimetric Application(Dedicated to Haim Brezis,great master of analysis,on his 70th birthday)

在线全文

学校读者我要写书评

暂无评论

Chinese Annals of Mathematics,Series B 2017年第2期38卷 661-686页

作者： Yannick SIRE Juan luis VAZQUEZ Bruno VOLZONE johns hopkins university Krieger Hall3401 N.Charles StBaltimoreM D21218USA. departamento de matemticas universidad autnoma de madrid28049 M adridSpain dipartimento di ingegneria universit degli studi di napoli"parthenope"80143 Italia.

This paper develops further the theory of symmetrization of fractional Laplacian operators contained in recent works of two of the authors. This theory leads to optimal estimates in the form of concentration comparison inequalities for both elliptic and parabolic equations. The authors extend the theory for the so-called restricted fractional Laplacian defined on a bounded domain Ω of R^N with zero Dirichlet conditions outside of Ω. As an application, an original proof of the corresponding fractional Faber-Krahn inequality is derived. A more classical variational proof of the inequality is also provided.

关键词： Symmetrization, Fractional Laplacian, Nonlocal elliptic and parabolicequations, Faber-Krahn inequality