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By Albert H. Herrera

La microcuenca Tres Ríos, está ubicada en el distrito de Cajamarca, Región Cajamarca y al NW de la ciudad de Cajamarca, abarcando el centro poblado de Chámis, Corizorgona, Collpayoj y parte de Ronquillo, con un área aproximada de 39.653055km2, a una elevación de 2800 a 3800msnm. Ubicada a 10 km aproximadamente de la ciudad de Cajamarca. Las Formaciones existentes en la microcuenca Tres Ríos son del Ki-desde el Aptiano (Grupo Goyllarisquizaga) con la Fm. Farrat hasta Ks-Turoniano con la Fm. Cajamarca. (Boletín 31.Serie a.-Geología del Perú-INGEMMET). Siendo las primeras Formaciones las más importantes a tomar en cuenta para la construcción reservorios artesanales para el almacenamiento del agua.

Sep 21, 2015

By Daniel Plasencia

Para el desarrollo del presente trabajo, se han realizado estudios de caracterización mineralógica correspondientes a diferentes muestras de la veta Bienaventurada y de la roca caja de la mina Bienaventurada (nivel 4230 zona SW) de la compañía minera Kolpa S.A. En la roca caja, se efectuaron estudios petrográficos y de DRX para determinar la composición de la roca y de sus alteraciones.

Sep 1, 2017

By Maria Anita de Paula Negreti

Neste trabalho, foram obtidos compósitos poliméricos de Óxido de Grafite (GO) incorporado em Poli(metaclilato de metila) (PMMA). A obtenção do Óxido de Grafite foi realizada pelo método de Hummers modificado. Em seguida foi ainda adicionada uma etapa secundária de tratamento térmico à 1000ºC no GO obtido a fim de expandir as lamelas de grafite e remover os grupos funcionais aderidos durante o ataque ácido do grafite. As cargas obtidas foram caracterizadas com o auxílio das técnicas de Difração de Raios-X (DRX), constatando a expansão das folhas após o tratamento térmico. O estudo comparativo dos compósitos de matriz polimérica com 3 % de concentração de GO antes e após o tratamento térmico foi realizado com o objetivo de entender a contribuição nas propriedades reológicas do polímero com a adição da carga de GO. Os resultados reológicos apresentaram um aumento da viscosidade complexa tanto no ensaio de Varredura de Tempo, quanto no Cisalhamento Oscilatório de Pequenas Amplitudes (COPA).

Aug 16, 2017

By Noan Tonini SImonassi

Compósitos cerâmicos de TiB2-AlN foram preparados por técnica de “spark plasma sintering”. A densidade máxima relativa e resistência foram de 96,9% e 16,2 GPa, respectivamente. As amostras foram submetidas a testes de usinagem de curto tempo. Os compósitos com 70% de AlN foram utilizados como ferramenta de corte e apresentaram resultados satisfatórios para os parâmetros de corte. Análises de Microscopia Eletrônica de Varredura (MEV) permitiram a análise da microestrutura e o desgaste da superfícies após os testes de corte.

Oct 30, 2017

By Alessandra Savazzini dos Reis

A indústria de cerâmica vermelha brasileira consome 10,3 bilhões de toneladas de argila ao mês para produção de telhas e blocos. Uma alternativa para tornar o setor mais sustentável ambientalmente é a incorporação de resíduos na massa argilosa. Na própria olaria são gerados resíduos, tal como, o resíduo de massa cerâmica crua originado na etapa de conformação das peças. Este trabalho visa caracterizar o resíduo de massa cerâmica crua para incorporação na massa argilosa usada em cerâmica vermelha. O resíduo de massa cerâmica crua foi caracterizado através de ensaios de FRX, DRX, calorimetria exploratória diferencial e termogravimetria, limites de Atterberg e distribuição de tamanho de partículas. Corpos de prova foram conformados, secos à 110ºC e queimados à 900ºC em forno industrial e foram submetidos a ensaios de absorção de água, porosidade aparente, massa específica aparente e resistência à flexão. Os resultados evidenciam que as propriedades cerâmicas avaliadas nos corpos de prova atendem aos valores das argilas-padrão brasileiras para uso em cerâmica vermelha.

Aug 16, 2017

By Amanda Coutinho Campanatti

O objetivo desse trabalho é caracterizar o processo de delaminação, tanto em Modo I como em Modo II, de abertura de trinca. A densidade e porcentagem de fibra do compósito carbono-epóxi foram calculadas para caracterizar o compósito. O inserto, para simular o início da trinca, foi feito no processo de fabricação dos compósitos a fim de manter sua integridade. Pelo mesmo motivo o corte foi feito a jato d’água. Para caracterização da delaminação foram feitos ensaios de DCB (Double-cantilever Beam) e ENF (End-notched Flexure), segundo as normas ASTM D5528 e ASTM D790-10, sendo ambos realizados na máquina universal de ensaio MTS, capacidade de 250 kN. A fractografia em Microscopia Eletrônica de Varredura (MEV) foi feita a fim de identificar os mecanismos de dano durante a propagação da trinca. Foi possível concluir a fabricação do compósito, bem como do inserto, é viável. Porém, houve aparecimento de bolhas, por causa da baixa pressão da bomba a vácuo. O corte a jato d’água manteve a integridade do compósito. A rigidez alta do compósito pode ser comprovada por meio das propriedades mecânicas obtidas pelo ensaio de tração. Os valores de GIC e GIIC estão dentro do esperado pela literatura, sendo GIIC maior que GIC por causa da presença de um capo de compressão no ensaio em modo II, enquanto que em modo I é abertura pura por tração.

Aug 7, 2018

By Carlos Bruno Eckstein, Cayo Vinicius da Silva Lima, Gabriela Ribeiro Pereira, Thiago Tôrres Matta Neves, Clara Johanna Pacheco, Laudemiro Nogueira Junior, Luiz Henrique de Almeida

Aços austeníticos HP atualmente são os materiais utilizados em tubos de fornos de reforma a vapor devido as suas propriedades superiores a altas temperaturas de operação. Por causa da exposição a ambientes oxidantes durante o serviço, na parede externa dos tubos é formada uma complexa camada de diferentes óxidos e, adjacente a esta, se forma região empobrecida de cromo. A presença de uma resposta magnética nesta região influencia diretamente o desenvolvimento de fermentas de inspeção não destrutiva para avaliação magnética da evolução microestrutural em fornos de reforma a vapor. Para caracterizar a resposta magnética desta camada transformada, foi utilizada uma amostra com estado de envelhecimento V utilizando-se a técnica de microscopia Kerr. Foram realizadas análises qualitativas por meio de imagens e análises quantitativas através do levantamento da curva de histerese. Os resultados permitiram identificar regiões com domínios magnéticos e correlacionar o seu comportamento com o valor do campo magnético aplicado.

Oct 29, 2019

By Mike Treffy

El presente texto describe las características geoquímicas de las rocas ígneas del tipo HHPG (High Heat Producing Granites) en los Andes peruanos. Dichas rocas tienen diferentes edades geológicas y están relacionadas a los depósitos minerales como estaño, plata, cobre, zinc, plomo, uranio, etc y están ubicadas al extremo sur de la Cordillera Oriental y norte del Batolito de la Cordillera Blanca. Asímismo, en base al procesamiento geoquímico de la de ANDESDATA, se demuestra que estos granitos y rocas volcánicas félsicas corresponden a diferentes series magmáticas y que este tipo de rocas pueden relacionarse a altas concentraciones de plata, oro, cobre, zinc, molibdeno, uranio, favoreciendo la circulación de fluidos hidrotermales a grandes distancias de las intrusiones y rocas volcánicas bastante diferenciadas.

Sep 21, 2013

By Jean-François Dorion

La corrosivité des environnements miniers souterrains est un phénomène peu étudié au Canada. En plus de détériorer les systèmes de soutènement, la corrosion s?attaque aussi à divers installations et équipements souterrains. Cette étude, débutée en janvier 2007, est l?établissement d?une banque de données afin de caractériser les environnements miniers souterrains selon leur potentiel de corrosivité pour les systèmes de support de terrains. Pour ce faire, cinq (5) mines ont été sélectionnées afin de comparer les environnements : Laronde, Géant-Dormant, Niobec, Mouska et Doyon. À chacune des mines, trois (3) endroits ont été étudiés. Les résultats préliminaires démontrent une grande variabilité des conditions d?une mine à l?autre ainsi qu?à l?intérieur même d?une mine. La minéralogie des roches et du gisement influence la composition des eaux souterraines et la présence des sulfures joue un rôle important sur l?agressivité de l?eau et de l?air des mines de l?étude. Afin de déterminer le potentiel de corrosivité, plusieurs paramètres doivent être considérés et la mine doit être zonée selon l?agressivité des endroits.

Feb 1, 2008

Table 1.-Salient statistics of carbon black produced from natural gas and liquid hydrocarbons in the United States [ ]

Jan 1, 1967

By Donald S. Colby

CARBON-BLACK shipments, which had declined in the latter art of 1953, remained low in 1954 until after settlement of the labor strike that occurred in the rubber industry in July and August. The production of new model automobiles in the last quarter of the year spurred the demand for rubber tires and consequently the demand for carbon black. Total shipments of 1,498 million pounds for the year were 4 percent below 1953.

Jan 1, 1958

By Ivan F. Avery

DOMESTIC production of carbon black increased 4 percent in 1962 to 2,056 million pounds. Furnace black output was 8 percent, or 132 million pounds, above that in 1961 and accounted for 90 percent of total carbon black production. Channel black output continued to decline and was 55 million pounds less than in 1961. Carbon black shipments during the year totaled 2,082 million pounds and were 5 percent above those of 1961. About one-fifth of these shipments were exported; the balance were sold domestically. An increase of 180 million pounds in domestic sales was partially offset by a decline of 80 million pounds in exports. Total value of carbon black production in 1962 was $145 million. The average value per pound of 7.06 cents was 0.24 cent per pound less than in 1961. Producers' stocks declined 26 million pounds during the year.

Jan 1, 1963

By William B. Harper

Domestic sales of carbon black sustained the upward movement for the 4th consecutive year, reflecting the increased sales of motor vehicles during the same period. Sales of carbon black in the domestic market topped 2 billion pounds for the first time during 1965 and have more than doubled the output of 20 years earlier. By far the largest user of carbon black is the rubber industry. That use accounted for more than 94 percent of the carbon black consumption with the bulk of it being used in tire casings and tubes. Thus demand for carbon black is naturally sensitive to trends in the sales of passenger cars and other motor vehicles, Manufacturers of inks, paints, plastics, paper chemicals, and food are also important users of carbon black.

Jan 1, 1967

By Carl W. Kelley

PRODUCTION in the United States of carbon black has increased from 20 million pounds per year in 1920 to over 2 billion pounds in 1964 valued at $156 million, mostly for consumption by the rubber-tire industry, which uses over 90 percent of total production. Production of over 2 billion pounds in 1964 is a 7.8-percent increase over 1963 and is the first time furnace black production has topped 2 billion pounds. Although 1964 channel black production dropped 6 percent below 1963, carbon black produced by the furnace process, which ac-counted for 92 percent of total production, increased 9 percent to 2,053 million pounds. Total shipments during 1964 amounted to 2,245 mil-lion pounds, a 7 percent increase. This growth parallels the expansion of the automotive and petroleum industries. Along with this expansion have been many advances, both in methods of manufacture and in the quality and variety of blacks available to industry. There are several kinds of carbon black, thermal, channel, furnace, lamp, and oil blacks. Until recently, channel has been the important black in rubber compounding. Following the introduction of the synthetic GR-S, and more recently of "cold rubber," it has been found that certain furnace blacks with particle size larger than that of the standard channel black give superior reinforcement. A great advantage of furnace black is that its yield per unit of gas feedstock is higher than that of channel black. The 184-million-pound increase in domestic carbon black sales was partially offset by a 37-million-pound decrease in exports. Decrease in exports especially to Europe, is expected to continue. In Europe, as in the United States, the major end use for carbon black is in the manufacture of automobile and truck tires. Although the number of automobiles in Europe is predicted to grow by about 7.5 percent per year, compounded until 1975, the increased demand will be met by a 20 percent increase in existing capacity and by the new plants being built in Europe by U.S. companies. Also) aromatic oils for producing furnace blacks are plentiful now that western Europe's chemical industry is switching to a petroleum base.

Jan 1, 1965

By Ivan F. Avery

DOMEST1C production of carbon black in 1963, remained at about the same level as in 1962. Carbon black produced by the furnace process increased 2 percent to 1,880 million pounds in 1963 and accounted for 91 percent of the total output. Channel black production continued to decline and was 14 percent less than a year ago. Shipments during 1963 totaled 2,098 million pounds, a 1 percent increase for the year. An increase of 88 million pounds in domestic sales was partially offset by a decrease of 72 million pounds in carbon black exports. Total value of carbon black production in 1963 was $148 million. The average value per pound was 7.18 cents or 0.12 cent per pound more than in 1962.

Jan 1, 1964

By B. P. Faulkner, M. Weinecke

Svedala started a development program in 1997 to develop a process to convert waste tires into valuable commodities. A review of numerous approaches revealed short-comings in the various approaches either process, mechanical, combination of factors, or trying to emphasis the production of low value products. A market study revealed that a process that could produce a good grade of carbon black would be economically feasible. This paper discusses the laboratory and pilot plant development and commercial plant design.

Jan 1, 2001

By D. Thibault, A. Akhiate, M. Brochu, E. Braud

Cast martensitic stainless steels, 13%Cr-4%Ni, having carbon contents between 0.018 wt% and 0.067 wt% were normalized, air quenched, and tempered at two different temperatures (550°C and 610°C). Their microstructures were characterized by optical microscopy and X-ray diffraction (XRD). Macro and microhardness, tensile strengths, and impact resistance were quantified for each material and condition. Results show that the prior-austenite grain size is constant through the materials but the percentage of reformed austenite, contained in the martensitic matrix, depends strongly on the material chemistry and on the tempering temperature and on its duration. It is observed that, independently of tempering conditions, an increase in carbon content increases the material hardness and tensile strengths, whereas the elongation remains constant. In contrast, the results of Charpy type impact toughness tests show a different trend. The material containing the average carbon content (0.034 wt%) is significantly tougher than the two other alloys. Surprisingly, the toughness of the steel containing 0.034 wt% carbon was found independent of the reformed austenite content. It is thus concluded that carbon and reformed austenite contents are not the only parameters affecting the toughness of these steels.

Jan 1, 2014

By D. J. Young

Alloys used at high temperature must resist both creep and corrosion. Design for corrosion resistance is based on the formation of a slow-growing, protective oxide scale by selective oxidation of an appropriate alloy component, usually chromium or aluminium. A successful scale will exclude other corrodents, notably carbon, which can otherwise cause extremely rapid corrosion at high temperatures. Selective oxidation of an alloy component necessarily lowers the concentration of that metal in the alloy subsurface region. Under thermal cycling conditions, mechanical damage to the scale leads to renewed oxide growth and accelerated alloy depletion. Eventually, a point is reached where diffusion of a corrodent into the alloy becomes competitive with the outward diffusion of alloy metal to repair the protective scale. Two examples of alloy failure by carbon attack are considered. In the steam cracking (pyrolysis) process, centrifugally cast tubes of heat-resisting alloy are exposed to a gas stream of hydrocarbon and steam, at a carbon activity of unity. Formation and repair of the surface chromia scale causes alloy depletion, Kirkendall void formation, and subsequent internal precipitation of chromium-rich carbides. Their formation makes chromia scale formation much more difficult, and generates internal stress. Eventually, the tubes fail by creep rupture. In other processes (e.g. steam reforming, heat treatment), synthesis gases are supersaturated with carbon at intermediate temperatures. Once the alloy's protective scale is breached, carbon attacks the depleted substrate. In the case of ferritic alloys, it forms a surface scale of Fe3C. As this scale thickens, the supersaturated carbon precipitates as graphite within its outer regions. The resulting volume expansion causes disintegration of the cementite in a process known as metal dusting. In the case of austenitic alloys, no metal carbide is formed. Instead, carbon dissolves in the depleted metal to diffuse inward and precipitate as graphite within the metal matrix. Again, volume expansion causes disintegration of the alloy, and metal dusting results. Dusting occurs at an extraordinarily rapid rate, and leads to failure by section loss or even penetration.

Jan 1, 2013

By Costello MC

An alternative process for desorbing and recovering metals from activated carbon has been developed, and is the subject of several patent applications by Micron Research (W.A.) The system uses the principle of conditioning the carbon in a strong alkaline cyanide solution followed by distillation desorption in a fractionating column, using the carbon as the column packing and methanol as the desorbing agent. The system offers the following advantages : (a) The processes of desorption, methanol recovery and reactivation are all carried out in a single column with the carbon itself acting as the column packing. No other desorption plant items or fractional distillation equipment are required. (b) The metal values are concentrated into the water content of the carbon and no other water is used except as condenser coolant. This produces very high grade gold silver solutions which give high current efficiencies in the electrowinning step. These high gold concentrations allow almost complete separation of gold and silver from copper in the electrolytic cell. (c) The process is completed to a tailing assay of less than 200g Au/tonne carbon in 15 - 20 hours allowing turn around of carbon batches on a daily Basis.

Jan 1, 1982

By J. Charles Miller

NATURAL carbon dioxide has recently been exploited in the United States in consequence of oil and gas developments in the Western States and the growing demand by transcontinental and transoceanic shippers for solid carbon dioxide. The discovery by drilling of commercial deposits resulted in consideration of its geographic and geologic distribution and occurrence. Its wide distribution in nature is evidenced by its occurrence in the atmosphere, hydrosphere and lithosphere. The question of origin of carbon dioxide involves consideration of theories similar to those concerning natural hydrocarbons, although available evidence favors an inor-ganic rather than an organic source. Areas favorable to development of commercial production appear to be those in proximity to igneous rocks or in the vicinity of decadent volcanic activity, where, it has long been known, the gas is evolved either free or dissolved in the waters of furnaroles, geysers or mud pots. Structure contour maps are presented showing the Wagon Mound anticline in New Mexico and the Farnham anticline, Utah. A well drilled on the latter supplies gas to a 20-ton plant manufacturing solid carbon dioxide at Wellington, Utah, on the Denver and Rio Grande R.R., whence it is shipped to surrounding territory and to the West Coast. Before funds are invested in a plant for the manufacture of liquid or solid carbon dioxide, whether supplied by wells or springs, an effort to ascertain the volume of gas available is advisable. The use of present methods of estimation of gas reserves with modifications to account for the quantity absorbed by any water present in the produc-ing formation is recommended. The Farnham anticline is used as an example and computations are made of the probable volume of gas originally present in the struc-ture. No attempt was made to compute reserves in the Niland area, California, for the reason that in such areas it is believed the volume is indeterminate.

Jan 1, 1937