检索结果-南通市图书馆

Treatability studies of naphthalene in soil,water and air with persulfate activated by iron(Ⅱ)

Journal of Environmental Sciences 2020年第4期32卷 67-77页

作者： Gabriela P.mendes Vivian m.A.magalhaes Lélia C·R·Soares Rayanne m.Aranha Claudio A.O.Nascimento marilda m.G.R.Vianna osvaldo Chiavone-Filho Department of Chemical Engineering University of Sao PauloSPf 05508-000Brazil Department of Chemical Engineering Federal University of Rio Grande Do NorteNatalRN59072-970Brazil

Chemical oxidation was applied to an artificially contaminated soil with naphthalene(NAP).Evaluation of NAP distribution and mass reduction in soil,water and air phases was carried out through mass *** of NAP distribution and mass reduction in soil,water and air phases was carried out through mass *** importance of the air phase analysis was emphasized by demonstrating how NAP behaves in a sealed system over a 4 hr reaction *** of Experiments method was applied to the following variables:sodium persulfate concentration[SP],ferrous sulfate concentration[FeS04],and *** system operated with a prefixed solid to liquid ratio of 1:*** following conditions resulted in optimum NAP removal[SP]=18.37 g/L,[FeSO4]=4.25 g/L and pH=*** the end of the 4 hr reaction,62%of NAP was *** the soil phase,the chemical oxidation reduced the NAP concentration thus achieving levels which comply with Brazilian and USA environmental *** the NAP partitioning view,the monitoring of each phase allowed the variabilities assessment over the process,refining the knowledge of mass *** on NAP distribution in the system,this study demonstrates the importance of evaluating the presence of semi-volatile and volatile organic compounds in the air phase during remediation,so that there is greater control of the system as to the distribution and presence of the contaminant in the *** results highlight the importance of treating the contaminant in all its phases at the contaminated site.

关键词： Chemical oxidation Phase distribution Degradation kinetics PAH Soil remediation mass balance

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Approximation method for the Relaxed Covariant Form of the Gravitational Field Equations for Particles

引用

Journal of modern Physics 2012年第9期3卷 1247-1254页

作者： Emanuel Gallo osvaldo m. moreschi FamAF Universidad Nacional de Córdoba Instituto de Fsica Enrique Gaviola (IFEG) CONICET Ciudad Universitaria Córdoba Argentina

We present a study of the so called relaxed field equations of general relativity in terms of a decomposition of the metric;which is designed to deal with the notion of particles. Several known results are generalized... 详细信息

关键词： General Relativity Approximation methods Particles

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Habitat and food preferences of European rabbits in core and edge populations along the invasion front Patagoniamonte,Argentina

引用

Current Zoology 2024年第3期70卷 310-319页

作者： Sabrina Yasmin Bobadilla maría A.Dacar Fabián m.Jaksic Ricardo A.Ojeda maría Fernanda Cuevas Ecología de mamíferos de Tierras Secas IADIZACCT-Mendoza CONICETAv.Ruiz Leal s/nParque General San MartínMendoza 5500MendozaArgentina Laboratorio de Filogeografía Taxonomía Integrativa y Ecología(LFTIE)IADIZACCT-Mendoza CONICETAv.Ruiz Leal s/nParque General San MartínMendoza 5500MendozaArgentina Center of Applied Ecology and Sustainability(CAPES) Pontifcia Universidad Católica de ChileAv.Libertador Bernardo O'Higgins 340Santiago 8320000Región MetropolitanaChile

The European rabbit Oryctolagus cuniculus is an exotic herbivorous mammal undergoing an active phase of geographical expansion in the arid ecosystems of *** Adaptive Flexibility Hypothesis states that populations at the range edge(new populations)will exhibit greater fexibility in the use of resources compared with populations located in the range core(older populations).The objective of this work was to compare the rabbit’s use of spatial and trophic resources in relation to the establishment time of their *** sampling was carried out for 2 years(2017 and 2018)in sites with different establishment times for rabbit *** sampling stratifed by type of habitat was applied using 115 fxed strip transects of 1,000 m^(2) laid out across the study *** rabbit signs were recorded in each transect,and environmental and anthropic variables were *** results show that the individuals from the range edge are more selective in the use of habitat than those from the range *** the microhabitat level,we observed a pattern in the particular components of habitat use by rabbits mainly linked to food availability and proximity to *** a trophic perspective,rabbits could show fexible adjustment to novel conditions and environments in the range *** variability in resource use by the European rabbit confrms its ecological fexibility,pivotal for their advance toward new environments in Argentina.

关键词： Arid ecosystems invasive species novel environments range invasion spatial use trophic use

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

mössbauer Spectroscopic Characterization of Fe Occupation of Columns in the Nb₂₈O₇₀ Structure

引用

World Journal of Condensed matter Physics 2023年第3期13卷 105-110页

作者： osvaldo F. Schilling Departamento de Fisica UFSC Florianópolis Brazil

In search of an experimental route to produce linear arrays of spins without the use of nanotechnological tools, we have doped Nb28O70 with small amounts of transition metal oxides (Tm;in this case Fe2O3) or rare-earth oxides3, and investigated the location of the alien metal (Fe in this case) in the structure. Previous AC magnetic susceptibility measurements at low temperatures have been consistent with the formation of arrays of Tm magnetic moments along the widely spaced columns parallel to the crystallographic b-axis in the Nb28O70 structure. To obtain further details about the Tm distribution, the previous investigation has been extended now to include a room-temperature mössbauer spectroscopic analysis of the Fe-doped material. The data are consistent with the presence of low-spin Fe3+ ions in both octahedral and tetrahedral coordinations of oxygens, and confirm (as suggested in the previous work) that Fe also interchanges positions with Nb ions located at tetrahedrally coordinated sites in the columns of the structure.

关键词： mössbauer Spectroscopy Niobium Oxides Spin Arrays

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Involvement of met receptor pathway in aggressive behavior of colorectal cancer cells induced by parathyroid hormone-related peptide

引用

World Journal of Gastroenterology 2022年第26期28卷 3177-3200页

作者： maría Belén Novoa Díaz Pedro Carriere Graciela Gigola Ariel osvaldo Zwenger Natalia Calvo Claudia Gentili Departamento de Biología Bioquímica y FarmaciaUniversidad Nacional del Sur(UNS)-INBIOSUR(CONICET-UNS)Bahía Blanca 8000Buenos AiresArgentina Centro de Estudios Clínicos SAGA CEC SAGASantiago de Chile 8320000Chile

BACKGROUND Parathyroid hormone-related peptide(PTHrP)plays a key role in the development and progression of many *** found that in colorectal cancer(CRC)HCT116 cells,the binding of PTHrP to its receptor PTHR type 1(PTHR1)activates events associated with an aggressive *** HCT116 cell xenografts,PTHrP modulates the expression of molecular markers linked to tumor *** evidence suggests that the met receptor is involved in the development and evolution of *** on these data,we hypothesized that the signaling pathway trigged by PTHrP could be involved in the transactivation of met and consequently in the aggressive behavior of CRC *** To elucidate the relationship among PTHR1,PTHrP,and met in CRC *** For in vitro assays,HCT116 and Caco-2 cells derived from human CRC were incubated in the absence or presence of PTHrP(1-34)(10-8 m).Where indicated,cells were pre-incubated with specific kinase inhibitors or dimethylsulfoxide,the vehicle of the *** protein levels were evaluated by Western blot ***-time polymerase chain reaction(RT-qPCR)was carried out to determine the changes in gene *** healing assay and morpho logical monitoring were performed to evaluate cell migration and changes related to the epithelialmesenchymal transition(EmT),*** number of viable HCT116 cells was counted by trypan blue dye exclusion test to evaluate the effects of irinotecan(CPT-11),oxaliplatin(OXA),or doxorubicin(DOXO)with or without *** in vivo tests,HCT116 cell xenografts on 6-wk-old male N:NIH(S)_nu mice received daily intratumoral injections of PTHrP(40μg/kg)in 100μL phosphate-buffered saline(PBS)or the vehicle(PBS)as a control during 20 *** slaughter was carried out and the tumors were removed,weighed,and fixed in a 4%formaldehyde solution for subsequent treatment by *** evaluate the expression of molecular markers in human tumor samples,we studied 23 specimens ob

关键词： PTHrP mET receptor tyrosine kinase Parathyroid hormone receptor type 1 Colorectal cancer Drug resistance

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Root proliferation in native perennial grasses of arid Patagonia,Argentina

引用

Journal of Arid Land 2014年第2期6卷 195-204页

作者： Yanina A TORRES Carlos A BUSSO Oscar A mONTENEGRO Leticia ITHURRART Hugo D GIORGETT Gustavo RODRíGUEZ Diego BENTIVEGNA Roberto E BREVEDAN osvaldo A FERNáNDEZ maría m mUJICA Sandra S BAIONI José ENTíO maría N FIORETTI Guillermo TUCAT Agronomy Department National University of the South and CERZOS (CONICET) Experimental Farm EEA INTA Patagones Ministery of Agrarian Issues Faculty of Agrarian Sciences National University of La Plata

Pappophorum vaginatum is the most abundant C4 perennial grass desirable to livestock in rangelands of northeastern Patagonia, Argentina. We hypothesized that （1） defoliation reduce net primary productivity, and root length density and weight in the native species, and （2） root net primary productivity, and root length density and weight, are greater in P. vaginatum than in the other, less desirable, native species （i.e., Aristida spegazzinfi, A. subulata and Sporobolus cryptandrus）. Plants of all species were either exposed or not to a severe defoliation twice a year during two growing seasons. Root proliferation was measured using the cylinder method. Cylindrical, iron structures, wrapped up using nylon mesh, were buried diagonally from the periphery to the center on individual plants. These structures, initially filled with soil without any organic residue, were dug up from the soil on 25 April 2008, after two successive defoliations in mid-spring 2007. During the second growing season （2008-2009）, cylinders were destructively harvested on 4 April 2009, after one or two defoliations in mid- and/or late-spring, respectively. Roots grown into the cylinders were obtained after washing the soil manually. Defoliation during two successive years did reduce the study variables only after plants of all species were defoliated twice, which supported the first hypothesis. The greater root net primary productivity, root length den- sity and weight in P. vaginatum than in the other native species, in support of the second hypothesis, could help to explain its greater abundance in rangelands of Argentina.

关键词： Aristida species competitive ability Pappophorum vaginatum Sporobolus cryptandrus warm-season perennial grasses

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The Farallon-Aluk ridge collision with South America:Implications for the geochemical changes of slab window magmas from fore- to back-arc

引用

Geoscience Frontiers 2013年第4期4卷 377-388页

作者： Eugenio Aragón Lucio Pinotti Fernando D'Eramo Antonio Castro osvaldo Rabbia Jorge Coniglio manuel Demartis Irene Hernando Claudia E.Cavarozzi Yolanda E.Aguilera Centro de Investigaciones Geologicas(UNLP-CONICET) 1 N°644(1900) La Plata.Buenos Aires.Argentina Facultad de Ciencias Naturales y museo Universidad Nacional de la Plata122 y 60s/n.(1900).La PlataBuenos AiresArgentina Departamento de Geologia.Universidad Nacional de Rio Cuarto.(UNRC-CONICET).Ruta 36 km 601.Rio Cuarto.Cordoba.Argentina Departamento de Geologia.Universidad de Huelva.21071 Huelva.Spain Instituto de Geologia Economica Aplicada.Universidad de Concepcion.Concepcion.Chile Departamento de Geologia.Universidad Nacional de Rio Cuarto.(UNRC-CONICET) Ruta 36 km 601.Rio Cuarto.CordobaArgentina Centro de Investigaciones Geologicas(UNLP-CONICET).1 N°644.(1900) La Plata.Buenos Aires.Argentina Facultad de Ciencias Naturales y museo.Universidad Nacional de la Plata.122 y 60 s/n.(1900).La PlataBuenos Aires.Argentina Facultad de Ciencias Naturales y museo.Universidad National dela Plata.122 y 60 s/n(1900)La Plata.Buenos Aires.Argentina Direccion de Aplicacion de Imagenes Satelitarias(m.O.S.P.).58 e/ 7 y 8.piso 2.1900 La Plata.Buenos Aires.Argentina

The collision of a divergent ocean ridge may evolve into two end cases： in the continuity of ocean-floor subduction, or in the detachment of the subducted plate. The northern Patagonia active plate margin has the unique situation that in Cenozoic time it has been subjected to two divergent ridge collisions, each one representing one of the end members. The Neogene Antarctica-Nazca divergent ridge collision evolved as a continuous ocean-floor subduction system, promoting a magmatic hiatus at the arc axis, the obduction of part of the ridge ocean-floor in the fore-arc, and basaltic volcanism in the back-arc. In contrast, the Paleogene Farallon-Aluk divergent ridge collision evolved into a transform margin, with the detachment and sinking of the Aluk plate and the development of a large slab window. As in the previous case, this collision promoted a magmatic hiatus at the arc axis, but the tectono-magmatic scenario changed to postorogenic synextensional volcanism that spread to the former fore-arc （basalt, andesite, rhyolite） and former back-arc （bimodal ignimbrite flare-up, basalt）. Geochemistry of this slab window synextensional volcanism shows more mORB-like basalts towards the former fore-arc, and mORB-OIB-Iike basalts towards the former back-arc. Instead, an isolated undeformable crustal block in the former back-arc, with an ＂epeirogenic＂ response to the slab window and extensional regime, was covered by OIB-type basalts after uplift. major elements show that slab window basalts reach TiO2 values up to 3 wt%, as compared with the top value of 1.5 wt% of arc magmas. Besides, the mgO with respect to （FeOt ＋ A1203） ratio helps to distinguish slab window magma changes from the former fore-arc to the former back-arc and also with respect to the ＂epeirogenic＂ block. Higher contents of HFS elements such as Nb and Ta also help to distinguish this slab window from arc magmas and also, to distinguish slab window magma changes from the former fore-arc to the former back-arc

关键词： AndesActive ridge collisionSubduction-transform transitionSlab window volcanismSynextensional calc-alkalineBimodal volcanism

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Failure Analysis of Austenitic Stainless Steel Implant Screws and Prospection of Chemical Composition Using Artificial Intelligence

引用

World Journal of Engineering and Technology 2022年第1期10卷 98-118页

作者： Alfonso monzamodeth Román-Sedano Bernardo Campillo Fermín Castillo osvaldo Flores Facultad de Química Universidad Nacional Autónoma de México Ciudad de México México Instituto de Ciencias Físicas Universidad Nacional Autónoma de México Cuernavaca Morelos México

In this work, austenitic stainless steel screws employed in a locking compression plate for veterinarian use were investigated. These types of implants are widely utilized in bone fractures healing. Two surgical screws were extracted due to the observation of slight superficial red rust colorizing on one of the screw implants, visual evidence of probable screw rusting. From the same implant, another screw was extracted simultaneously without visual evidence of rusting. In order to characterize and analyze the different behavior of both screws, the chemical composition was characterized by atomic absorption and energy dispersive X-ray spectroscopy (EDS) coupled to a scanning electron microscope (SEm). Also, the screws were studied by metallography, optical microscopy (Om), Vickers microhardness tests, and SEm analysis. On the other hand, a prospection for alloy chemical composition limits of these types of implants was performed based on the Schaeffler-Delong diagram and the ASTm F-138 standard. To analyze the effect of the chemical composition, heat treatment, microstructure, pitting resistance equivalent number (PRE) and stacking fault energy (SFE), a genetic algorithm (GA) and an artificial neural network (ANN) were used. In accordance with the elemental analysis, the surgical screws do not fulfill the ranges of the chemical composition established by the ASTm F-138 standard. Furthermore, there were found differences between the microstructures of the screws. In regard to the prospection, the results of GA and ANN support the proposed chemical composition region on the Schaeffler-Delong diagram. The corrosion failure was associated with severe plastic deformation and the presence of precipitates. The proposal can minimize the cause of failures in these types of austenitic stainless steel implants.

关键词： Implant Screw Failure Analysis Genetic Algorithm Artificial Neural Network Austenitic Stainless Steel

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Effect of the Substitution of Sand by Rubber of Waste Tires on the mechanical Properties of Hydraulic Concrete and Exposure to Gamma Radiation

引用

Journal of minerals and materials Characterization and Engineering 2021年第3期9卷 245-256页

作者： Jesús m. Colín de la Cruz Carmen Gabriela Guzmán Fermín Castillo mejía Benjamin Leal Acevedo osvaldo Flores Cedillo Isabel Gamboa de Buen Arturo molina Ocampo Horacio martínez Valencia Facultad de Ciencias Químicas e Ingeniería Universidad Autónoma del Estado de Morelos Cuernavaca México Laboratorio de Espectroscopia Instituto de Ciencias Físicas Universidad Nacional Autónoma de México Cuernavaca México Instituto de Ciencias Nucleares Universidad Nacional Autónoma de México México City México Centro de Investigación en Ingeniería y Ciencias Aplicadas UAEM Cuernavaca México

For a long time and until now, rubber is the most used material for the manufacture of tires for motor vehicles. Unfortunately, once the tire meets its life cycle, the remaining rubber cannot be recycled, so the tires are discarded in collection centers and often in clandestine dumps. This represents a serious environmental problem because, in one case, these waste tires become breeding grounds for insects and wildlife that is harmful to humans. In the second case, the tires are burned, releasing highly damaging gases into the atmosphere. On the other hand, concrete is worldwide the construction material par excellence. It is basically composed of cement, gravel and sand. mixing these three components in different proportions, their mechanical strength in compression can be increased. However, due to its fragile nature, concrete, once a crack is formed, it rapidly advances by fragmenting the material and producing its rapid collapse. In the present work, in order contribute to the care of the environment as well as to modify the fracture mode of the concrete, rubber particles obtained from waste tires were used as sand substitute in hydraulic concrete. In addition, rubber modified samples concrete were lately exposed to 70 kGy of gamma radiation in order to study the effects of this radiation on the mechanical deformation of concrete. The results showed a decrease in the mechanical properties of the concrete with rubber particles with respect to the traditional concrete itself. However, such decreases were offset by the fact that samples with rubber addition do not collapses as fast as the free rubber samples. The acquired data pave the way for research with great benefits, such as the use of recycled tires in concrete for its fracture mode modification in a beneficial way, as well as a possible decrease in the cost of concrete.

关键词： Hydraulic Concrete Scrap Tire Rubber Strength Gamma Radiation mechanical Properties

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Silver Recovery from Spent Silver Oxide Button Cell by Liquid-Liquid Extraction

引用

Journal of materials Science and Chemical Engineering 2015年第7期3卷 148-153页

作者： Zeferino Gamino-Arroyo Antonio Tapia-Cisneros osvaldo m.Zamacona-Saucedo Irene Cano-Rodríguez Alberto F.Aguilera-Alvarado Lorena E.Sánchez-Cadena Fernando I.Gómez-Castro Departamento de Ingeniería Química Universidad de Guanajuato Guanajuato México Departamento de Ingeniería Civil Universidad de Guanajuato Guanajuato México

Button cell batteries are used in clocks, thermometers, remote controls, toys and other devices, and they are usually discarded in the trash once its useful life is over. Some models of these batteries contain silver oxide. In this paper we propose liquid-liquid extraction as separation process to recover the metal. First, silver determination is performed in different models of these batteries and leaching with nitric acid is carried out. Affinity study is done between several commercial extractants for silver. The best performing extractant is the bis(2-ethylhexyl) dithiophosphoric acid (D2EHDTPA). Furthermore, a study of the extraction yields as a function of extractant concentration and time is performed. The distribution isotherm is determined;complex extracted in organic phase and stripping conditions have been identified. With the aim of obtaining industrial application, a number of steps for a countercurrent process were defined by the mcCabe-Thiele method. Finally, a study was done in micropilot scale. The results show that it is possible to recover silver from this type of waste.

关键词： Silver Spent Button Cells Leaching Recovery

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：