Production of Asphalt Rubber Concrete by the Dry Process, HR-1062, 1994

Disposal of used tires has been a problem throughout the United States. The 1991 Intermodal Surface Transportation Efficiency Act (ISTEA) requires the use of recycled rubber in asphalt concrete starting in FY94. A moratorium has delayed this requirement until FY95. The Iowa DOT has researched six projects using crumb rubber modifier in asphalt concrete using the wet process. This process involves using a blender-reactor to blend the asphalt cement and crumb rubber. Using the wet process the asphalt cement has to reach a hotter temperature, than is normally required, for reaction to occur. The wet process is also much more expensive than conventional asphalt. This research deals with using a dry process to incorporate crumb rubber into the asphalt concrete mix. The project was constructed by Western Engineering of Harlan, Iowa, on IA 37 between Earling, Iowa and US 59. It was completed in September 1993. Western Engineering used a double drum mixer to produce the crumb rubber modified asphalt concrete by the dry process. The production and construction went well with minor difficulty and the dry process is a less expensive procedure for producing crumb rubber modified asphalt concrete.

Suuren kapasiteetin paloittelusahakonseptin kehittäminen

Asiakkaat vaativat lisää kapasiteettia ja joustavuutta eli levylinjan paloittelusahan tapauksessa pieniä palakokoja. Vaatimukseen on lähdetty vastaamaan tuotekehitysprojektilla, jonka yksi osa-alue on uuden paloittelusahan konseptin kehitys. Konseptin kehityksen lähtökohtana on ajatus terien lukumäärän lisäämisestä, terien suunnan kääntämisestä levypinkan liikesuunnan myötäiseksi, sekä terien pitämisestä paikallaan levypinkan liikkuessa niiden läpi. Tässä työssä konseptin kehitykseen kuuluu purunpoistojärjestelmä, sahattujen hukkapalojen käsittely, murskaus ja poisto, sekä levypinkan siirtomenetelmä sahauskokonaisuuden läpi. Kirjallisuusosassa on paneuduttu puulevyjen ja pyörösahauksen teoriaan. Diplomityössä on tutkittu eri pohjaratkaisujen vaikutusta kapasiteettiin, sekä vaihtoehtoja paloittelusahan eri osa-alueiden ratkaisuiksi. Lisäksi on tutkittu murskauksen tehovaatimusta vertaamalla mitattuja arvoja laskettuihin arvoihin. Tutkimuksen otannan puitteissa todettiin laskettujen arvojen johtavan reiluun moottoreiden ylimitoitukseen.

Asphalt Resurfacing Structural Research, HR-556, Construction Report, 1995

Discarded tires present major disposal and environmental problems. One method of recycling tires is to use finely ground rubber from tires in asphalt cement concrete (ACC). This process has been researched in Iowa since 1991. There are currently eight projects being researched. This project involved using crumb rubber modifier (CRM) in ACC using a dry process. This project is located on US 63 in Howard County. It involved 17 test sections. There were five test sections using 20 lb of CRM per ton, four test sections using 10 lb of CRM per ton and eight test sections using a conventional mix. Not only were different mixes used, but the overlay was also placed in various thicknesses ranging from 2 in. to 8 in. (5 cm to 20 cm). The project was completed in August 1994. The project construction went well with only minor problems. This report contains information about procedures and tests that were completed and those that will be completed. Evaluation on the project will continue for five years.

Perfil logístico del sector cemento en Colombia

Este proyecto caracteriza la logística del sector cemento en Colombia al identificar y describir los principales actores, procesos y materiales involucrados en la cadena de suministros del sector. Este documento compila la información logística relevante para la producción de cemento en Colombia. Esta información se obtuvo sintetizando estudios y reportes acerca de las prácticas logísticas y las condiciones en las que éstas se desarrollan. Adicionalmente se realizaron visitas empresariales en diferentes plantas de producción de cemento y entrevistas semiestructuradas a expertos en logística de los diferentes eslabones. Con la información primaria y secundaria se caracteriza del producto, las materias primas e insumos necesarios para la producción de cemento. Se identifican los principales agentes que componen el sector y se describen los procesos logísticos relacionados con el cemento en cada uno de ellos. Para las cementeras y canteras se hace un análisis de entradas y salidas de los procesos principales de su cadena de valor. Adicionalmente se expone la operación de transporte como un elemento clave en el sector y se presentan las simulaciones de fletes, rutas y cubicaje. Por último, se incluye un caso de optimización de transporte aplicando teorías de investigación de operaciones.

Perfil logístico del sector del cemento en Colombia

Este proyecto caracteriza la industria del cemento en Colombia a partir de la contextualización y descripción de esta actividad en el mundo y en el país, describiendo y analizando asuntos relacionados con la cadena de suministro de esta. Teniendo en cuenta los actores directos e indirectos que en esta interactúan y temas como el comercio internacional, el desempeño y la competitividad regional de la industria nacional, la percepción empresarial y factores como la responsabilidad social y las buenas prácticas. Además de la descripción de los factores nacionales que afectan a la industria como la infraestructura, el transporte y el desempeño logístico del país. En la contextualización mundial se presentan temas como la producción, oferta y demanda mundial de este producto y las principales tendencias y prácticas logísticas que caracterizan a esta industria internacionalmente; en el panorama nacional se caracteriza la competitividad y desempeño logístico del país y los factores que afectan a la industria del cemento. Se presentan los orígenes e historia de la industria en el país y se dan datos de la producción, despachos y comercio internacional de esta además de una breve descripción de su cadena de suministro y la caracterización de las relaciones entre sus eslabones. Finalmente se describen los entes con los cuales interactúa la industria, se describe lo más relevante en cuanto a políticas ambientales, responsabilidad social y buenas prácticas de los principales productores del país y se concluye con la caracterización de la competitividad general de la industria a nivel nacional y los retos y problemáticas que afronta el sector y que lo limitan para mejorar su desempeño a nivel regional.

Estudo de Matérias-Primas do Rio Grande do Norte para Uso em Revestimento Poroso: Influência do teor de dolomita e temperatura de calcinação nas propriedades físico-mecânicas

The state of Rio Grande do Norte presents a great potentiality for the production of ceramic tiles because of having natural raw material in quantity and quality making its economical exploration possible, beyond the great energetic differential of the state, the natural gás. This works aims to study the influence of the dolomite and granulometry concentration and calcinations temperature in the obtaining of formulations for porous coverings which have to be coherent to the project,s specifications. The experiments have involved the physical-chemical and mineralogical characterizations of raw materials and mechanical tests in the dry and burnt proof bodies preceding a mixture experiment planning with the use of the response surface methodology, in order to get the best raw materials combinations to produce a ceramic mass with specific properties. The twelve ceramic masses studied in this work were prepared by the via dry process, characterized, shaped by uniaxial pressing and sinterized in the temperatures of 940ºC, 1000ºC, 1060ºC, 1120ºC and 1180ºC, using a fast burning cycle. The crystalline phases formed during the sintering in the temperatures in study have revealed the presence of anorthite and diopside beyond quartz with a remaining phase. These phases were the main responsible ones by the physical- mechanical properties of the sinterized proof bodies. The proof bodies after the sintering stage have presented water absorption higher than 10% and a good dimensional stability in all studied temperatures. However, the flexural breaking strength results in the temperatures of 940ºC, 1000ºC and 1060ºC, under the temperature zone of the vitrification of ceramic whiteware do not reach the flexural breaking strength specific for the porous wall tile (15 MPa), but in the temperature of 1120ºC next to the vitrification temperature zone, some whiteware ceramic (formulations) has reached the specified value for the porous wall tile. The results of this work have showed that the studied raw materials have great importance for used in the production of porous wall tiles (BIII)

Obtenção de placas cerâmico a partir de formulações de massas triaxiais de resíduos de caulim, chamote de telha e cinza vegetal

The production of red ceramic is an industrial activity that causes an intense impact. The manufacture of its products considerably increases the demand for natural resources, mainly with the extraction of raw material. The ceramic material produced generates waste, such as ash firewood and chamote. The residue from the beneficiation of kaolin is deposited in a poor, degrades the environment and contaminate water sources and soil, constituting in this manner, ecological disasters. The main objective of this work is to develop the formulation of a ceramic product consisting solely of industrial solid wastes, from ceramic tiles, (chamote) residue of kaolin and ash firewood. It is assumed that this product made in the laboratory can be used in coatings, wall and floor. The aim is to facilitate the replacement of the raw material of original composition of a ceramic body, for waste, while the process of production equal to the conventionally used, so that the properties of the product are reproduced. This work is characterized waste as its chemical composition, analysis of particle size, X-ray diffraction and thermal behavior. Several formulations were studied. The mass of waste was prepared by dry process, pressed to 25 MPa, and then burned in muffle type oven to 850, 950, 1050 and 1150 °C. The results showed that it is technically possible to produce porous tiles only with waste. It was found that the formulations of bodies play a key role in the properties of the final product, as well as the sintering temperature and heating rates. RN in the waste of kaolin is estimated at 15,000 t/month, about 3,000 gray t/month and chamote with 10 million pieces/month damaged. The presence of carbonates of calcium and magnesium at 1050 ° C results in an appropriate porosity and mechanical strength. The formulation M3JE, composed of 69% waste of kaolin, 7.7% and 23.3% of chamote of gray, became suitable for porous materials with the strength and absorption within the level of national and international standards

Influência do teor e granulometria da calcita e da temperatura de sinterização no desenvolvimento de massas cerâmicas para revestimento poroso(BIII)

This work aims at studying the influence of the concentration of calcite, its grain size and sintering temperature to obtain porous coating formulations that meet the design specifications. The experiments involved the physical-chemical and mineralogical caracterization of the raw materials, and mechanical tests on specimens dried and sintered, performing a planning mixture and factorial experiment, using the response surface methodology. The ceramic bodies studied were prepared by dry process, characterized, placed in conformity by uniaxial pressing and sintered at temperatures of 940 º C, 1000ºC, 1060ºC, 1120°C and 1180°C using a fast-firing cycle. The crystalline phases formed during sintering at temperatures under study, revealed the presence of anorthite and wolastonite, and quartz-phase remaining. These phases were mainly responsible for the physical and mechanical properties of the sintered especimens. The results shown that as increases the participation of carbonate in the composition of ceramic bodies there is an increase of water absorption and a slight reduction in linear shrinkage for all sintering temperatures. As for the mechanical strength it was observed that it tended to decrease for sintering at temperatures between 940 ° C and 1060 ° C and to increase for sintering at temperatures above 1060 ° C occurring with greater intensity for compositions with higher content of calcite. The resistence decreased with increasing participation of quartz in all sintering temperatures. The decrease in grain size of calcite caused a slight increase in water absorption for formulation with the same concentration of carbonate, remaining virtually unchanged the results of linear shrinkage and mechanical strength. In conclusion, porous ceramic coating (BIII) can be obtained using high concentrations of calcite and keeping the properties required in technical standards and that the particle size of calcite can be used as tuning parameter for the properties of ceramic products.

Doping of polyaniline by corona discharge

In the present article it is shown that a corona discharge can be employed to dope thin films of polyaniline (PANI) coated on poly(ethylene terephthalate) films, allowing the electrical conductivity to be tuned within the range 10(-10) to 0.3 S cm(-1). A study of the effect of different corona conditions, namely corona treatment for positive and negative polarities, air humidity, treatment time, corona current, and the geometry of the corona triode, on the electrical conductivity of the polyaniline is presented. The results indicate that the corona discharge leads to protonic doping of polyaniline similar to that which occurs in conventional protonic acid solution doping. Atomic force microscopic analysis shows that, as the PANI is exposed to the corona discharge, its globular morphology is disrupted leading to the appearance of droplet-like features and a significant decrease in the average height and surface roughness. Doping by corona discharge presents several advantages over the conventional solution method namely that it is a dry process which does not require use of chemicals reagents, and which is both rapid and avoids dopant migration. The latter can be important for applications of PANI in microelectronic devices. (C) 2000 American Institute of Physics. [S0021-8979(00)01608-X].

Liberação de nitrogênio e potássio da palha de café em função da adubação nitrogenada

Pós-graduação em Agronomia (Agricultura) - FCA

Emprego da reflectometria por domínio do tempo na determinação da umidade de madeiras comerciais

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Estudo de rejeitos de galvanoplastia e a sua aplicação na fabricação de peças cerâmicas rústicas para fins decorativos

Pós-graduação em Geologia Regional - IGCE

Loss of desiccation tolerance in Copaifera langsdorffii Desf. seeds during germination

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Calibração de um equipamento TDR (Reflectometria por Dominio do Tempo) para a Determinação da Umidade da Madeira de Grevillea robusta (Cunn.)

This study aimed to establish a calibration model of a TDR equipment to determinate thewood moisture of Grevillea robusta (Cunn.). It was selected alleatory, 11 logs of Grevillea robusta (Cunn.), it was dried in a regulate electric greenhouse at 40o C. During the dry process, the moisture was determinate, periodically and systematically by gravimetric and TDR methods. Through the gravimetric method, moisture vary from 125,88% to 6,62% while the TDR method, the variation was from 119,83% to 5,79%. The best model adjusted to the wood moisture in the determination of the function of relative dielectric constant, using this technique, was the exponential 50,20 132,72 140,27 K U e − = − ⋅ , with a R2 = 0,96, with indicator of trust or performance 0,97 they were classified as very good, according to Camargo and Sentelhas (1997). The correlation between the gravimetric method (reference) and TDR, showed to be equivalent for both methodologies. It was concluded that the TDR can be used to the determination of wood moisture of Grevillea robusta (Cunn.), in a precise and fast way, once it was established it calibration.

Diseño electrónico de la tarjeta de interfaz y control para un equipo de seguimiento en elevación en un subsistema de contramedidas electrónicas

Como apoyo al Subsistema ECM tradicional de los sistemas de Guerra Electrónica, surge el Equipo de Seguimiento en Elevación cuyo fin es la búsqueda de la amenaza en elevación. Ante la necesidad de un mayor número de líneas entre los bloques internos de este Equipo de Seguimiento, se hace necesario el diseño de una Tarjeta de Interfaz y Control. La tarjeta se ocupará de realizar el control de datos y flujo de señales de módulos RF que componen el Equipo, haciendo de interfaz entre las Tarjetas Procesadoras y Digitalizadoras, así como entre la Tarjeta de Proceso y el Bloque de Recepción. Una vez que se haya realizado el análisis de la necesidad de controlar estas señales, estudiado las especificaciones y los requisitos funcionales del Sistema, se procederá a implementar el diseño hardware y desarrollo firmware de la Tarjeta de Interfaz y Control de un Equipo de Seguimiento en Elevación para un Subsistema ECM, que constituye el objetivo de este PFC. ABSTRACT. In order to find a threat on elevation, and as a support on the basic ECM subsystems of E-war systems, the Elevation Tracking Equipment appears. To the need of a bigger number of lines between inside blocks of this Tracking Equipment, the design of an Interface and Control Board is needed. This board will deal with the data control and with the flow of RF modules signals that set up the Equipment, and will also work as an interface between the Processing and Digitalizing Board, as well as between the Process Board and the Reception Block. Once the signal control necessity analysis has been made, and once the specifications and functional System requirements have been studied, the hardware design and the firmware development will be ran as a target of PFC.