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Hydrolysis of Urea to Produce Ammonia Dircio francisco Xavier Fatima Ximenes

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Hydrolysis of Urea to Produce Ammonia Dircio Francisco Xavie...

作者： Dircio francisco Xavier Fatima Ximenes（弗朗西斯科）华东理工大学

学位级别：硕士

氮氧化物（NOx）引起了巨大的环境问题,是目前世界上最大的环境污染物之一,随着对NOx法规的逐步收紧,世界各国都在积极开展减少NOx污染的研究。目前已开发利用了多种技术,其中选择性催化还原（SCR）和选择性非催化还原（SNCR）具有较高... 详细信息

氮氧化物（NOx）引起了巨大的环境问题,是目前世界上最大的环境污染物之一,随着对NOx法规的逐步收紧,世界各国都在积极开展减少NOx污染的研究。目前已开发利用了多种技术,其中选择性催化还原（SCR）和选择性非催化还原（SNCR）具有较高的脱硝效率。在SCR和SNCR工艺中,还原剂被注入烟气中,将NOx还原为无害氮（N2）。目前最常用的还原剂是氨（NH3）。尿素催化水解制氨在氨基脱氮过程中起着重要作用。本论文的目标有三个。首先,对尿素水解的催化剂进行筛选,其中均相催化剂表现出了良好的性能,因此本文用选择该类催化剂来进行尿素催化水解反应,然后尿素水解的转化率采用滴定法来进行分析。第二是设计了四因素,三水平Box-Behnken实验,结合响应面法对工艺条件进行优化,研究反应温度,反应时间,反应压力和催化剂用量对尿素水解制氨的影响及其交互作用。建立了尿素水解率的相关模型。第三是采用物料平衡方程,热量平衡方程,化学平衡方程及相平衡方程组成的非线性方程组来构建开口体系内尿素水解过程的热力学模型和动力学模型,并引入修正的Lewis-Randall方程和修正的Herry方程来描述水解反应器内NH3-CO2-H2O-（NH2）2CO（ACWU）四元多自由度气液平衡关系,气液两相的非理想性则分解采用PR状态方程和扩展UNIQUAC模型进行修正。结果表明,采用催化活性较好的乙酸钠（7g）催化剂对工艺条件进行优化,响应面法最优化的合成条件为;反应温度160℃,反应时间4h,反应压力0.4MPa和催化剂用量0.034wt%,在此工艺条件下尿素水解的转化率为98.620%,同时建立了尿素水解制氨的二次数学模型,该模型对实验结果有良好的预测作用。

关键词：尿素水解制氨热力学动力学

Splenic rupture following colonoscopy

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World Journal of Gastroenterology 2008年第41期14卷 6410-6412页

作者： Juan francisco Guerra Ignacio San francisco Fernando Pimentel Luis Ibanez Departamento de Cirugía Digestiva Pontificia Universidad Católica de Chile Marcoleta 367

Colonoscopy is a safe and routinely performed diagnostic and therapeutic procedure for different colorectal diseases. Although the most common complications are bleeding and perforation, extracolonic or visceral injuries have also been described. Splenic rupture is a rare complication following colonoscopy, with few cases reported. We report a 60-year-old female who presented to surgical consultation 8 h after a diagnostic colonoscopy. Clinical, laboratory and imaging findings were suggestive for a massive hemoperitoneum. At surgery, an almost complete splenic disruption was evident, and an urgent splenectomy was performed. After an uneventful postoperative period, she was discharged home. Splenic injury following colonoscopy is considered infrequent. Direct trauma and excessive traction of the splenocolic ligament can explain the occurrence of this complication. Many times the diagnosis is delayed because the symptoms are due to colonic insuffl ation, so the most frequent treatment is an urgent splenectomy. A high index of suspicion needs an early diagnosis and adequate therapy.

关键词： Colonoscopy Splenic injury Splenic rupture Splenectomy

Impact of ZnSO_(4)^(-)and ZnO Nanoparticles on Seed Germination and Seedling Growth of Lettuce

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Phyton-International Journal of Experimental Botany 2023年第6期92卷 1831-1840页

作者： Adalberto Benavides-Mendoza Rebeca Betancourt-Galindo Nazario francisco-francisco Departamento de Horticultura Universidad Autónoma Agraria Antonio NarroSaltillo25315México Departamento de Materiales Avanzados Centro de Investigación en Química AplicadaSaltillo25294México Departamento de Agricultura Sustentable y Protegida Universidad Tecnológica de TehuacánTehuacán75859México

Micronutrient nanoparticles(NPs)are currently an option for chemical fertilization and biostimulation in ***,there is little information on the phytotoxic or biostimulatory effects of NPs at low concentrations of some elements,such as *** this study,the effect of low concentrations of Zn oxide(ZnO)NPs on germination,growth variables,and nutritional attributes of lettuce(Lactuca sativa L.)was evaluated in comparison to Zn *** lettuce seeds were treated with ZnSO_(4)^(-)×7H_(2)O and ZnO NPs at Zn molar concentrations of 1×10^(−3),5×10^(−3),1×10^(−4),5×10^(−4),1×10^(−5),5×10^(−5),1×10^(−6),and 5×10^(−6).The seeds treated with ZnSO4−at 5×10^(−6)registered the highest radicle length,73%more than the control *** seeds treated with ZnSO4−at 5×10^(−3)registered the lowest values,with 50%less than the control *** NPs at 5×10^(−6)significantly increased content of chlorophyll A and B and total *** results indicate the possible existence of a mechanism related to the intrinsic nanoparticle properties,especially at low concentrations.

关键词： Micronutrients biostimulation nanotechnology nanofertilizers germination chlorophyll total phenols

The quest for selective Cs^(+) transport in plants

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Molecular Plant 2021年第4期14卷 552-554页

作者： Manuel Nieves-Cordones francisco Rubio Departamento de Nutricion Vegetal Centro de Edafologia y Biologia Aplicada del Segura-CSICCampus de Espinardo30100 MurciaSpain

Nuclear accidents have led to the release to the environment of radioactive isotopes,mainly radioactive cesium(Cs^(+)),contaminating large areas of soil for very long periods of time(Burger and Lichtscheidl,2018).These contaminated soils contain^(134)Cs^(+)and^(137)Cs^(+)radioisotopes that are readily accumulated into plants and that,through the food chain,are transferred to animals and humans,causing important health problems(Burger and Lichtscheidl,2018).

关键词： readily release transport

Floral biology and pollination mechanisms of four Mexico-endemic Fuchsia species with contrasting reproductive systems

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Journal of Plant Ecology 2018年第1期11卷 123-135页

作者： Clementina González Anai Alvarez-Baños Eduardo Cuevas CONACYT-Instituto de Investigaciones sobre los Recursos Naturales Universidad Michoacana de San Nicolás de HidalgoAv.San Juanito Itzícuaro s/nCol.Nueva EsperanzaMorelia Michoacán 58330México Facultad de Biología Universidad Michoacana de San Nicolás de HidalgoAv.Francisco J.Mújica S/NCiudad UniversitariaMoreliaMichoacán 58030México Departamento de Biología Vegetal y Ecología Universidad de SevillaApartado 109541080 SevillaSpain

Aims The evolution of the outstanding variation of reproductive systems in angiosperms has been considered an important driver of line-age *** related hermaphroditic and dioecious species with biotic pollination provide the opportunity to study and compare traits related to pollinator attraction and their con-sequences on reproductive components.A higher predictability of pollination syndromes is expected in dioecious species,which are dependent on pollinators,than in self-compatible hermaphroditic *** species may suffer pollen limitation depending on the quality of floral rewards and the kind and abundance of pollina-tors,whereas no pollen limitation is expected in hermaphroditic spe-cies with autonomous ***,in the absence of pollen limitation,more or better seeds are expected in dioecious species,according to the sexual specialization *** In natural populations of the hermaphroditic Fuchsia fulgens and Fuchsia arborescens and dioecious Fuchsia parviflora and Fuchsia obconica,all endemic to Mexico,we first described flower phenol-ogy,flower production and longevity and nectar volume and ***,we evaluated the correspondence between floral visitors and pollination *** hermaphrodite plants,we determined the level of herkogamy and the potential for autonomous ***,we evaluated the effect of pollen limitation on fruit set and seed number and assessed seed germination for all *** Findings In contrast to our prediction,dioecious species did not show a higher correspondence between pollination syndromes and floral visitors than did hermaphrodites;however,male flowers exhib-ited a higher correspondence than female *** pollen limitation was detected in dioecious species,for which visitation rate did not differ between male and female *** her-maphroditic *** showed pollen limitation for seed number,despite the presence of auto

关键词： dioecy herkogamy hermaphroditism pollen limitation pollination syndromes

SPLITTING SCHEMES FOR A NAVIER-STOKES-CAHN-HILLIARD MODEL FOR TWO FLUIDS WITH DIFFERENT DENSITIES

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Journal of Computational Mathematics 2014年第6期32卷 643-664页

作者： francisco Guillen-Gonzalez Giordano Tierra Departamento de Ecuaciones Diferenciales y Andlisis Numgrico and IMUS Universidad de Sevilla 41012 Seville Spain Department of Applied and Computational Mathematics and Statistics University of Notre Dame Notre Dame IN 46556 USA

In this work, we focus on designing efficient numerical schemes to approximate a ther- modynamically consistent Navier-Stokes/Cahn-Hilliard problem given in [3] modeling the mixture of two incompressible fluids with different densities. The model is based on a diffuse-interface phase-field approach that is able to describe topological transitions like droplet coalescense or droplet break-up in a natural way. We present a splitting scheme, decoupling computations of the Navier-Stokes part from the Cahn-Hilliard one, which is unconditionally energy-stable up to the choice of the potential approximation. Some nu- merical experiments are carried out to validate the correctness and the accuracy of the scheme, and to study the sensitivity of the scheme with respect to different physical pa- rameters.

关键词： Two-phase flow Diffuse-interface phase-field Cahn-Hilliard Navier-Stokes,Energy stability Variable density Mixed finite element Splitting scheme.

Increasing Powers in a Degenerate Parabolic Logistic Equation

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Chinese Annals of Mathematics,Series B 2013年第2期34卷 277-294页

作者： Jos francisco RODRIGUES Hugo TAVARES Department of Mathematics and CMAF Universidade de LisboaAvenida Professor Gama Pinto 21649-003 LisboaPortugal

The purpose of this paper is to study the asymptotic behavior of the positive solutions of the problem tu- △u=au-b（x）up in Ω×R＋,u（0）=u0,u（t ）｜ Ω=0, as p→ ＋∞, where Ω is a bounded domain, and b（x） is a nonnegative function. The authors deduce that the limiting configuration solves a parabolic obstacle problem, and afterwards fully describe its long time behavior.

关键词： Parabolic logistic equation Obstacle problem Positive solution Increasing power Subsolution and supersolution

Shear velocity criterion for incipient motion of sediment

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Water Science and Engineering 2014年第2期7卷 183-193页

作者： francisco J.M.SIMOES U.S. Geological Survey Geomorphology and Sediment Transport LaboratoryGolden CO 80403 USA

The prediction of incipient motion has had great importance to the theory of sediment transport. The most commonly used methods are based on the concept of critical shear stress and employ an approach similar, or identical, to the Shields diagram. An alternative method that uses the movability number, defined as the ratio of the shear velocity to the particle＇s settling velocity, was employed in this study. A large amount of experimental data were used to develop an empirical incipient motion criterion based on the movability number. It is shown that this approach can provide a simple and accurate method of computing the threshold condition for sediment motion.

关键词： incipient motion sediment transport Shields diagram critical shear stress criticalshear velocity movability number

Enhancement of the Antigenotoxic and Antioxidant Actions of Eugenol from Spice Clove and the Stabilizer Gum Arabic on Colorectal Carcinogenesis

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Food and Nutrition Sciences 2024年第1期15卷 71-100页

作者： Nayanna de Oliveira Ramos Melo Lucas Gabriel da Costa Marques Humberto Maia Costa Neto Matheus De Sousa Silva francisco Vagnaldo Fechine Jamacaru Bruno Coêlho Cavalcanti Antônio Adailson De Sousa Silva Conceição Aparecida Dornelas Postgraduate Program in Medical-Surgical Sciences School of Medicine Federal University of Ceará Fortaleza Brazil School of Medicine Federal University of Ceará Fortaleza Brazil Nucleus of Research and Development of Medicines (NPDM) Laboratory of Pharmacology and Preclinical Research School of Medicine Federal University of Ceará Fortaleza Brazil Nucleus for Research and Development of Medicines (NPDM) National Laboratory of Experimental Oncology Federal University of Ceará Fortaleza Brazil Postgraduate Program in Pathology and Medical-Surgical Sciences School of Medicine Federal University of Ceará Fortaleza Brazil

Spices are defined as any aromatic condiment of plant origin used to alter the flavor and aroma of foods. Besides flavor and aroma, many spices have antioxidant activity, mainly related to the presence in cloves of phenolic compounds, such as flavonoids, terpenoids and eugenol. In turn, the most common uses of gum arabic are in the form of powder for addition to soft drink syrups, cuisine and baked goods, specifically to stabilize the texture of products, increase the viscosity of liquids and promote the leavening of baked products (e.g., cakes). Both eugenol, extracted from cloves, and gum arabic, extracted from the hardened sap of two species of the Acacia tree, are dietary constituents routinely consumed virtually throughout the world. Both of them are also widely used medicinally to inhibit oxidative stress and genotoxicity. The prevention arm of the study included groups: Ia, IIa, IIIa, Iva, V, VI, VII, VIII. Once a week for 20 weeks, the controls received saline s.c. while the experimental groups received DMH at 20 mg/kg s.c. During the same period and for an additional 9 weeks, the animals received either water, 10% GA, EUG, or 10% GA + EUG by gavage. The treatment arm of the study included groups Ib, IIb, IIIb e IVb, IX, X, XI, XII). Once a week for 20 weeks, the controls received saline s.c. while the experimental groups received DMH at 20 mg/kg s.c. During the subsequent 9 weeks, the animals received either water, 10% GA, EUG or 10% GA + EUG by gavage. The novelty of this study is the investigation of their use alone and together for the prevention and treatment of experimental colorectal carcinogenesis induced by dimethylhydrazine. Our results show that the combined use of 10% gum arabic and eugenol was effective, with antioxidant action in the colon, as well as reducing oxidative stress in all colon segments and preventing and treating genotoxicity in all colon segments. Furthermore, their joint administration reduced the number of aberrant crypts and th

关键词： Eugenol Gum Arabic Carcinogenesis Oxidative Stress Genotoxicity