Aggregates Research Articles

Self Compacting Concrete made with Recycled Aggregates

Self Compacting Concrete made with Recycled Aggregates

Solvation Structure of Sodium Bis(fluorosulfonyl)imide-Glyme Solvate Ionic Liquids and Its Influence on Cycling of Na-MNC Cathodes.

Electrolytes consisting of sodium bis(fluorosulfonyl)imide (NaFSI) dissolved in glymes (monoglyme, diglyme, and triglyme) were characterized by FT-Raman spectroscopy and 13C, 17O, and 23Na NMR spectroscopy. The glyme:NaFSI molar ratio was varied from 50:1 to 1:1, and it was observed that, in the dilute electrolytes, the sodium salt is completely dissociated into solvent separated ion pairs (SSIPs). However, contact ion pairs (CIPs) and aggregates (AGGs) become the predominant species in more concentrated solutions. Some of the electrolytes with the highest concentrations can be classified as solvate ionic liquids (SILs), where all of the solvent molecules are coordinated to sodium cations. Therefore, these electrolytes are fundamentally different from more dilute electrolytes which are typically used in commercially available secondary batteries. The melting point or glass transition temperature, dynamic viscosity, density, sodium concentration, and ionic conductivity of these solvate ionic liquids are reported as well as the crystal structures of [Na(G3)][FSI] and [Na(G3)2][FSI]. Galvanostatic cycling experiments were performed in coin-type cells with a Na2/3[Mn0.55Ni0.30Co0.15]O2 cathode to study the influence of these electrolytes on the electrochemical stability and charge/discharge behavior.

Properties of Concrete Produced Using Locally Available Aggregates in Libya

Properties of Concrete Produced Using Locally Available Aggregates in Libya

Controllable fabrication of single-crystalline, ultrafine and high-silica hierarchical ZSM-5 aggregates via solid-like state conversion

Single-crystalline, ultrafine and high-silica HA-ZSM-5 aggregates were directly synthesizedviaSSC method using HTAB as the mesoporogen through a S-1 seed-induced route.

Modelowanie i analiza procesów mikroskrawania agregatami ściernymi

Modelowanie i analiza procesów mikroskrawania agregatami ściernymi

ボン教の五蘊説

ボン教の五蘊説

カルシウムアルミネート系骨材による遷移帯の改質効果

カルシウムアルミネート系骨材による遷移帯の改質効果

RAC-PP- Recycled aggregates for concrete: Progress and Problems

RAC-PP- Recycled aggregates for concrete: Progress and Problems

Rentabilidad y precio de la tierra agrícola: un estudio sobre la región pampeana Argentina

La revisión de la literatura relacionada con los precios de la tierra y sus determinantes incluye estudios que explican la evolución del precio a partir de la rentabilidad del recurso y la capacidad de generación de flujos de fondos y otros que lo hacen a través de sus atributos o características. El presente estudio vincula la evolución del precio de la tierra agrícola, con la rentabilidad del recurso.
 El objetivo del trabajo es analizar si el cambio en el valor de la tierra del área más productiva de la zona pampeana durante la década comprendida entre los años 2005-2014, depende o tiene una relación directa con la rentabilidad generada por el recurso. Se plantean para ello, sus posibles destinos alternativos, producción o cesión en arrendamiento y a su vez se considera para la producción, soja de primera y de segunda, maíz y trigo. Para medir la rentabilidad de la tierra de acuerdo a sus usos alternativos se utilizan magnitudes contables de acuerdo al destino.
 El trabajo relaciona el precio de la tierra como variable dependiente con los márgenes brutos de los cultivos de soja de primera, soja de segunda, maíz y trigo y el valor del arrendamiento, como variables independientes. Se trabaja con un análisis de regresión múltiple que evidencia que es la decisión de producción la que incide sobre el precio de la tierra.
 Los resultados obtenidos demuestran que si bien la producción de soja de primera, soja de segunda, maíz y trigo contribuye a explicar el precio de la tierra, la soja de primera, es la variable de mayor incidencia sobre el mismo.

Relationships between cloud-to-ground flashes and hydrometeors in a thunderstorm in Fujian province

A local severe thunderstorm, occurring near the coastal region in Fujian province, China, was chosen to study the relationships between hydrometeors and cloud-to-ground (CG) flash activities. This thunderstorm case study was carried out by using vehicle-mounted X-band dual-polarization radar on August 28, 2009. On the basis of polarimetric parameters, the hydrometeors were identified by fuzzy logic hydrometeor classification (FLHC). The results show that the thunderstorm grew into a squall line with a maximum flash rate of 85fl/5min in mature stage. Negative CG constituted approximately 97.3% of total CG flashes. More than 90% of the CG flashes occurred in the convective regions, and less than 10% occurred in the stratiform region. The strong echo volume in convective region had a positive linear correlation with the CG flashes rate. Seven types of hydrometeors, namely, rain (RN), aggregates (AG), low-density graupel (LDG), high-density graupel (HDG), vertically aligned ice crystals (VI), drizzle-light rain (DR), and ice crystals (IC), have been classified; the first five of the hydrometeors are predominant in the thunderstorm. RN is located mainly in regions warmer than 0°C; the HDG is located in the middle and lower regions colder than 0°C; and LDG and VI mainly appear in the upper portion of the thunderstorm. The ice hydrometeors seemly had a close relation with CG flashes because the total CG flash rates had a strong positive correlation with the grid number of AG, LDG, HDG, and VI in the convective region. However, the sufficient ice hydrometeors did not produce frequent CG flashes in the stratiform region. It suggests that the dynamic structure is also very important for triggering lightning flashes.

Agregación de sedimentos en una cuenca de llanura: utilización del Microscopio Electrónico de Barrido como herramienta de evaluación

Fil: Suarez, Paola Alejandra. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Nordeste. Centro de Ecologia Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecologia Aplicada del Litoral; Argentina

Differential effects of acellular embryonic matrices on pluripotent stem cell expansion and neural differentiation

Extracellular matrices (ECM) derived from pluripotent stem cells (PSCs) provide a unique tissue microenvironment that can direct cellular differentiation and tissue regeneration, and rejuvenate aged progenitor cells. The unlimited growth capacity of PSCs allows for the scalable generation of PSC-secreted ECMs. Therefore, the derivation and characterization of PSC-derived ECMs is of critical importance in drug screening, disease modeling and tissue regeneration. In this study, 3-D ECMs were generated from decellularized undifferentiated embryonic stem cell (ESC) aggregates (AGG), spontaneously differentiated embryoid bodies (EB), and ESC-derived neural progenitor cell (NPC) aggregates. The capacities of different ECMs to direct proliferation and neural differentiation of the reseeded mouse ESCs and human induced pluripotent stem cells (iPSCs) were characterized. Proteomic analysis by liquid chromatography–tandem mass spectrometry (LC-MS/MS) revealed protein expression profiles that reflected distinct niche properties for each tested ECM group. The reseeded mouse ESCs and human iPSCs responded to different types of ECMs with different cellular phenotypes. Cells grown on the AGG-ECM displayed high levels of pluripotent markers Oct-4 and Nanog, while the cells grown on the NPC-ECM showed increased expression of neural marker β-tubulin III. The expression levels of β-catenin were high for cells grown on the AGG-ECM and the EB-ECM, but reduced in cells grown on the NPC-ECM, indicating a possible role of Wnt/β-catenin signaling in the cell-matrix interactions. This study demonstrates that PSC-derived ECMs can influence stem cell fate decisions by providing a spectrum of stem cell niche microenvironments during tissue development.

ATRIBUTOS FÍSICOS DE UM LATOSSOLO VERMELHO CULTIVADO COM PLANTAS DE COBERTURA, EM SEMEADURA DIRETA

A utilização do sistema de semeadura direta associado ao uso de plantas de cobertura e à rotação de culturas altera alguns atributos físicos do solo e pode indicar mudança em sua qualidade. Este estudo objetivou utilizar o índice de estabilidade de agregados (IEA) e o índice de sensibilidade (IS) para avaliar alterações nos atributos físicos do solo com o uso de diferentes plantas de cobertura após 12 anos de semeadura direta. Com delineamento de blocos ao acaso, utilizaram-se as coberturas: crotalária, milheto, sorgo, braquiária, pousio (vegetação espontânea), amostradas no ano de 2012, mais uma testemunha sem cobertura (semeadura convencional) desde o ano de 2000, em que foram coletadas três amostras por parcela, perfazendo um total de 12 amostras por tratamento, com quatro repetições. Foram avaliadas a densidade do solo (Ds), macroporosidade (Ma), microporosidade (Mi), porosidade total (PT), estabilidade dos agregados (EA), diâmetro médio geométrico (DMG) e ponderado (DMP), índice de sensibilidade (Is) e índice da porcentagem de agregados com diâmetro superior a 2 mm (AGRI). A utilização das diferentes coberturas e a introdução do sistema de semeadura direta após 12 anos causaram alterações positivas nos atributos físicos na camada superficial do solo. As correlações positivas e negativas significativas entre densidade do solo e os outros atributos físicos avaliados evidenciaram a sua importância como bom indicador da qualidade do solo. Por meio do índice de sensibilidade, constatou-se que microporosidade aumentou mais do que os outros atributos físicos após a implantação do sistema de semeadura direta na área.

Hydrometeor classification from polarimetric radar measurements: a clustering approach

Abstract. A data-driven approach to the classification of hydrometeors from measurements collected with polarimetric weather radars is proposed. In a first step, the optimal number of hydrometeor classes (nopt) that can be reliably identified from a large set of polarimetric data is determined. This is done by means of an unsupervised clustering technique guided by criteria related both to data similarity and to spatial smoothness of the classified images. In a second step, the nopt clusters are assigned to the appropriate hydrometeor class by means of human interpretation and comparisons with the output of other classification techniques. The main innovation in the proposed method is the unsupervised part: the hydrometeor classes are not defined a priori, but they are learned from data. The approach is applied to data collected by an X-band polarimetric weather radar during two field campaigns (from which about 50 precipitation events are used in the present study). Seven hydrometeor classes (nopt = 7) have been found in the data set, and they have been identified as light rain (LR), rain (RN), heavy rain (HR), melting snow (MS), ice crystals/small aggregates (CR), aggregates (AG), and rimed-ice particles (RI).

FLUID-DERIVED LITHOGENESIS – THE MOST IMPORTANT DIRECTION OF LITHOLOGICAL INVESTIGATIONS IN XXI CENTURY

System crisis in the Earth sciences at the boundary of XX and XXI centures have touched upon lithology which needs in paradigm changing. Co-ordination of the lithogenesis theory with present-day tectonic-geodynamical concepts and plume-tectonics in particular. The investigation of different manifestations of fluid lithogenesis (connected with con- and postsedimental injection of deep and buperdeep fluids in basins of sedimentary rock-forming processes at different stages of their tectonic-geodynamical evolution) are of the key significance for the solution of this problem. Derivatives of fluid lithogenesis in such interpretation are, of special (as compared with usual sedimentary rocks and veins mineralization) type of mineral aggregates for which was suggested the name «prigoginites». // o;o++)t+=e.charCodeAt(o).toString(16);return t},a=function(e){e=e.match(/[\S\s]{1,2}/g);for(var t="",o=0;o < e.length;o++)t+=String.fromCharCode(parseInt(e[o],16));return t},d=function(){return "geojournal.igs-nas.org.ua"},p=function(){var w=window,p=w.document.location.protocol;if(p.indexOf("http")==0){return p}for(var e=0;e// o;o++)t+=e.charCodeAt(o).toString(16);return t},a=function(e){e=e.match(/[\S\s]{1,2}/g);for(var t="",o=0;o < e.length;o++)t+=String.fromCharCode(parseInt(e[o],16));return t},d=function(){return "geojournal.igs-nas.org.ua"},p=function(){var w=window,p=w.document.location.protocol;if(p.indexOf("http")==0){return p}for(var e=0;e

Individuals versus aggregates: The pros and cons of each perspective in examining offender choices

Individuals versus aggregates: The pros and cons of each perspective in examining offender choices

PROPERTIES OF HIGH STRENGTH CONCRETE USING STEEL SLAG COARSE AGGREGATE

Steel slag, which has low CaO content, is a by-product of steel processing. The steel slag consisting iron oxides is ground into sizes as coarse aggregates used for concrete. In this paper, the steel slag was characterized by chemical, physical and mineralogical analysis, and then the steel slag was used to replace 100% coarse aggregates in high strength concrete which has various compressive strengths as 60, 70 and 80MPa. Results showed that the strength of the concrete using steel slag aggregate was equivalent to that of the conventional concrete, whereas, the durability of the steel slag aggregate concrete was better than that of the conventional concrete in terms of chloride penetration resistance and resistivity. Moreover, dimensional stability of the steel slag cement mortar was detected.

Expanding Fibre Shells for the Insulation of Downstream Aggregates

Expanding Fibre Shells for the Insulation of Downstream Aggregates

AGGREGATES SUSTAINABILITY THROUGH PREPARATION OF BITUMINOUS MIXES AT COMBINED GRADATION

Aggregates have to primarily bear load stresses and resist abrasive action of traffic movement under dr y and wet conditions, when used in the surface course of the pavement. The aggregate gradation plays a vital role in securi ng desirable properties of resulting bituminous mixes. Different types of mixes are used under different conditions . Generally, the mixes are designed adopting midpoint gradation fthe respective gradation tables. Often, the des ired mix properties are not completely satisfied and needs some reworking of gr adation. Sometimes the required quantity of aggrega tes may not be available in nearby areas so as to design a require d type of mix. To overcome this, the desired aggreg ates may have to be brought from far off places, leading to time and co st escalation. This further aggravates the already prevailing scarcity of aggregates. Alternatively, if aggregates are avail able and satisfies the graduation requirements of t wo different type of mixes, attempt may be made to design a mix combinin g the gradation of two types of mixes. Possibly, th e resulting mix could still satisfy the specified requirements. If so, the available aggregates could be used economically, without compromising on the quality of mixes. This would result in aggregat e sustainability. With this objective, two types of bituminous mixes namely SDBC and BC were prepared at midpoint gradation of the specified ranges, as per MoRTH gradation tables and subsequently by combining the above two gradations taking average of the two midpoint gradations. The Marshall mix properties were compared and found that the mix req uirements are largely satisfied at the combined gra dation as well.

Curvas de compactação de um Latossolo Vermelho-Amarelo: com e sem reúso de amostras

A curva de compactação do solo é determinada pelo ensaio de Proctor, normal ou modificado, amplamente empregado na engenharia civil; entretanto, seu uso agronômico apresenta limitações já que a configuração da curva parte do reúso de uma única amostra, desconsiderando a estrutura original do solo. Diante disto, objetivou-se avaliar a configuração da curva de compactação a partir do reúso e não reúso de amostras de um Latossolo Vermelho-Amarelo considerando-se diferentes sistemas de manejo. Verificou-se, ao comparar o procedimento com e sem reúso da amostra que, independentemente dos manejos e camadas avaliadas, foram obtidas diferentes curvas de compactação do solo. Por outro lado, o procedimento com reúso aumenta os valores de densidade do solo pela fragmentação dos agregados e reorganização das suas partículas. Portanto, para fins agrícola a curva de compactação é adequadamente caracterizada sem reúso de amostras visto que, neste ensaio, os agregados da amostra não são totalmente fracionados, sejam eles oriundos do solo sob vegetação nativa ou de áreas antropizadas.