Teollisuusj��tteen k��ytt�� kiinteytys-stabiloinnin sideaineena ja haitta-aineiden stabiloinnin tehostamisessa

T��ss�� kanditaatinty��ss�� selvitettiin kuinka erilaiset sideaineseokset soveltuvat raskas-metallien sitomiseen 28 vuorokautta stabiloiduissa n��ytteist��. Ty��ss�� oletettiin teollisten j��tefraktioiden k��yt��n tehostavan er��iden metallien, kuten kupari ja sinkki, immobilisointia liev��sti pilaantuneista maa-aineksista. Kokeellisessa osassa stabiloitiin Kokkolan satamasta ruopattua sedimentti��, jonka sinkkipitoisuudet olivat ylitt��neet saastuneen sedimentin ohjearvon (���400 mg/kg). Sedimenttiin lis��ttiin eri sideaineseoksia ja n��ytteiden annettiin stabiloitua 28 vuorokautta, mink�� j��lkeen niist�� testattiin liukenevat raskasmetallit muokatulla ravistelutestill��. Eri sideaineseoksilla saatuja tuloksia verrattiin pelk��n yleissementin k��ytt����n. Lis��ksi erillisist�� n��ytteist�� otettiin pyyhk��isyelektronimikros-koopilla (SEM) kuvia havainnollistamaan stabiloitumista. N��iss�� n��ytteiss�� k��ytettiin samoja sideaineita kuin tehdyiss�� kokeissa. Liukoisuustestien tuloksista voidaan huomata n��ytteiss�� ongelmalliseksi raskasmetalliksi identifioidun sinkin sitoutuvan parhaiten sementin ja kipsin sekoituksella. My��s tuhkaa sis��lt��v��t sideainesekoitukset pienensiv��t sinkin liukoisuutta verrattuna pelkk����n yleis-sementtiin. Jatkotutkimuksissa voitaisiin testata erilaisia sideainesekoituksia betonira-kentamisessa, joilla saadaan ainakin 25 MPa lujuusarvo, pilaantunutta sedimentti�� tai maa-ainesta k��ytt��en.

Caracterizaci��n de costras y anillos en hornos rotatorios de cemento por Yadira Gonz��lez Carranza

Tesis (Maestr��a en Ciencias con Especialidad en Ingenier��a Cer��mica) U.A.N.L.

Desarrollo de un m��todo para evaluar materiales con potencial puzol��nico para su uso en cemento

Tesis (Doctor en Ingenier��a con Especialidad en Materiales) U.A.N.L.

Studies on the Quality of Rainwater at Various Land Use Locations and Variations by Interaction with Domestic Rainwater Harvesting Systems

The present study focused on the quality of rainwater at various land use locations and its variations on interaction with various domestic rainwater harvesting systems.Sampling sites were selected based upon the land use pattern of the locations and were classified as rural, urban, industrial and sub urban. Rainwater samples were collected from the south west monsoon of May 2007 to north east monsoon of October 2008, from four sampling sites namely Kothamangalam, Emakulam, Eloor and Kalamassery, in Ernakulam district of the State of Kerala, which characterized typical rural, urban, industrial and suburban locations respectively. Rain water samples at various stages of harvesting were also collected. The samples were analyzed according to standard procedures and their physico-chemical and microbiological parameters were determined. The variations of the chemical composition of the rainwater collected were studied using statistical methods. It was observed that 17.5%, 30%, 45.8% and 12.1% of rainwater samples collected at rural, urban, industrial and suburban locations respectively had pH less than 5.6, which is considered as the pH of cloud water at equilibrium with atmospheric CO,.Nearly 46% of the rainwater samples were in acidic range in the industrial location while it was only 17% in the rural location. Multivariate statistical analysls was done using Principal Component Analysis, and the sources that inf1uence the composition of rainwater at each locations were identified .which clearly indicated that the quality of rain water is site specific and represents the atmospheric characteristics of the free fall The quality of harvested rainwater showed significant variations at different stages of harvesting due to deposition of dust from the roof catchment surface, leaching of cement constituents etc. Except the micro biological quality, the harvested rainwater satisfied the Indian Standard guide lines for drinking water. Studies conducted on the leaching of cement constituents in water concluded that tanks made with ordinary portland cement and portland pozzolana cement could be safely used for storage of rain water.

Development of Polymer Cement Composites

Research in the field of polymer modified cement has been carried out for the last 70 years or more. Polymers are mostly used to enhance durability and sustainability of cement concrete and in combination with classical construction materials a synergistic effect is obtained. In this work different polymers were added to Portland cement in various proportions and the mechanical and chemical resistance properties of the resultant composites when exposed to chemical environments were studied. Microstructural studies were also carried out to investigate the morphology of the composite and analyse the nature of interactions taking place between the cement and polymer phases. Though most polymers did not improve the compressive strength of the cement paste, it was found that they enhanced the resistance of the virgin cement paste to external chemical environments. The polymers seal the pores in the cement matrix and bridge the microcracks within the composite. Some of the polymers underwent chemical interactions with the cement paste thereby interfering in the hydration of cement. Polymers also decreased the leachability of water soluble components of virgin cement resulting in composites having improved durability. An attempt to correlate the structure of the polymers with the properties of the resultant composites is also presented.

Behaviour of laterised normal and self compacting concrete subjected to elevated temperatures

Concrete is a universal material in the construction industry. With natural resources like sand and aggregate, fast depleting, it is time to look for alternate materials to substitute these in the process of making concrete. There are instances like exposure to solar radiation, fire, furnaces, and nuclear reactor vessels, special applications like missile launching pads etc., where concrete is exposed to temperature variations In this research work, an attempt has been made to understand the behaviour of concrete when weathered laterite aggregate is used in both conventional and self compacting normal strength concrete. The study has been extended to understand the thermal behaviour of both types of laterised concretes and to check suitability as a fire protection material. A systematic study of laterised concrete considering parameters like source of laterite aggregate, grades of Ordinary Portland Cement (OPC) and types of supplementary cementitious materials (fly ash and GGBFS) has been carried out to arrive at a feasible combination of various ingredients in laterised concrete. A mix design methodology has been proposed for making normal strength laterised self compacting concrete based on trial mixes and the same has also been validated. The physical and mechanical properties of laterised concretes have been studied with respect to different variables like exposure temperature (200��C, 400��C and 600��C) and cooling environment (air cooled and water cooled). The behaviour of ferrocement elements with laterised self compacting concrete has also been studied by varying the cover to mesh reinforcement (10mm to 50mm at an interval of 10mm), exposure temperature and cooling environment.

Behavior of geopolymer concrete exposed to elevated temperatures

The research in the area of geopolymer is gaining momentum during the past 20 years. Studies confirm that geopolymer concrete has good compressive strength, tensile strength, flexural strength, modulus of elasticity and durability. These properties are comparable with OPC concrete.There are many occasions where concrete is exposed to elevated temperatures like fire exposure from thermal processor, exposure from furnaces, nuclear exposure, etc.. In such cases, understanding of the behaviour of concrete and structural members exposed to elevated temperatures is vital. Even though many research reports are available about the behaviour of OPC concrete at elevated temperatures, there is limited information available about the behaviour of geopolymer concrete after exposure to elevated temperatures. A preliminary study was carried out for the selection of a mix proportion. The important variable considered in the present study include alkali/fly ash ratio, percentage of total aggregate content, fine aggregate to total aggregate ratio, molarity of sodium hydroxide, sodium silicate to sodium hydroxide ratio, curing temperature and curing period. Influence of different variables on engineering properties of geopolymer concrete was investigated. The study on interface shear strength of reinforced and unreinforced geopolymer concrete as well as OPC concrete was also carried out. Engineering properties of fly ash based geopolymer concrete after exposure to elevated temperatures (ambient to 800 ��C) were studied and the corresponding results were compared with those of conventional concrete. Scanning Electron Microscope analysis, Fourier Transform Infrared analysis, X-ray powder Diffractometer analysis and Thermogravimetric analysis of geopolymer mortar or paste at ambient temperature and after exposure to elevated temperature were also carried out in the present research work. Experimental study was conducted on geopolymer concrete beams after exposure to elevated temperatures (ambient to 800 ��C). Load deflection characteristics, ductility and moment-curvature behaviour of the geopolymer concrete beams after exposure to elevated temperatures were investigated. Based on the present study, major conclusions derived could be summarized as follows. There is a definite proportion for various ingredients to achieve maximum strength properties. Geopolymer concrete with total aggregate content of 70% by volume, ratio of fine aggregate to total aggregate of 0.35, NaOH molarity 10, Na2SiO3/NaOH ratio of 2.5 and alkali to fly ash ratio of 0.55 gave maximum compressive strength in the present study. An early strength development in geopolymer concrete could be achieved by the proper selection of curing temperature and the period of curing. With 24 hours of curing at 100 ��C, 96.4% of the 28th day cube compressive strength could be achieved in 7 days in the present study. The interface shear strength of geopolymer concrete is lower to that of OPC concrete. Compared to OPC concrete, a reduction in the interface shear strength by 33% and 29% was observed for unreinforced and reinforced geopolymer specimens respectively. The interface shear strength of geopolymer concrete is lower than ordinary Portland cement concrete. The interface shear strength of geopolymer concrete can be approximately estimated as 50% of the value obtained based on the available equations for the calculation of interface shear strength of ordinary portland cement concrete (method used in Mattock and ACI). Fly ash based geopolymer concrete undergoes a high rate of strength loss (compressive strength, tensile strength and modulus of elasticity) during its early heating period (up to 200 ��C) compared to OPC concrete. At a temperature exposure beyond 600 ��C, the unreacted crystalline materials in geopolymer concrete get transformed into amorphous state and undergo polymerization. As a result, there is no further strength loss (compressive strength, tensile strength and modulus of elasticity) in geopolymer concrete, whereas, OPC concrete continues to lose its strength properties at a faster rate beyond a temperature exposure of 600 ��C. At present no equation is available to predict the strength properties of geopolymer concrete after exposure to elevated temperatures. Based on the study carried out, new equations have been proposed to predict the residual strengths (cube compressive strength, split tensile strength and modulus of elasticity) of geopolymer concrete after exposure to elevated temperatures (upto 800 ��C). These equations could be used for material modelling until better refined equations are available. Compared to OPC concrete, geopolymer concrete shows better resistance against surface cracking when exposed to elevated temperatures. In the present study, while OPC concrete started developing cracks at 400 ��C, geopolymer concrete did not show any visible cracks up to 600 ��C and developed only minor cracks at an exposure temperatureof 800 ��C. Geopolymer concrete beams develop crack at an early load stages if they are exposed to elevated temperatures. Even though the material strength of the geopolymer concrete does not decrease beyond 600 ��C, the flexural strength of corresponding beam reduces rapidly after 600 ��C temperature exposure, primarily due to the rapid loss of the strength of steel. With increase in temperature, the curvature at yield point of geopolymer concrete beam increases and thereby the ductility reduces. In the present study, compared to the ductility at ambient temperature, the ductility of geopolymer concrete beams reduces by 63.8% at 800 ��C temperature exposure. Appropriate equations have been proposed to predict the service load crack width of geopolymer concrete beam exposed to elevated temperatures. These equations could be used to limit the service load on geopolymer concrete beams exposed to elevated temperatures (up to 800 ��C) for a predefined crack width (between 0.1mm and 0.3 mm) or vice versa. The moment-curvature relationship of geopolymer concrete beams at ambient temperature is similar to that of RCC beams and this could be predicted using strain compatibility approach Once exposed to an elevated temperature, the strain compatibility approach underestimates the curvature of geopolymer concrete beams between the first cracking and yielding point.

An��lisis de la Pol��tica Exterior Rusa en materia energ��tica, comercial y militar hacia la Rep��blica de Moldavia (Per��odo 2000-2010)

Rusia sufri�� grandes cambios tras la desintegraci��n de la URSS en 1991. No obstante, con la llegada de Vladimir Putin al poder, los intereses geoestrat��gicos de Rusia sobre el espacio postsovi��tico revivieron con nuevo ��mpetu debido a una mayor cantidad de recursos a disposici��n del Estado. La Rep��blica de Moldavia es un claro ejemplo del resurgir de la pol��tica exterior rusa hacia el espacio postsovi��tico, siendo incluso, una regi��n clave en la lucha de la Federaci��n Rusa por recuperar su zona de influencia.

Derecho penal y la obligaci��n de investigar y sancionar graves violaciones de derechos humanos y el derecho internacional humanitario -especial referencia a la sentencia de la corte constitucional colombiana c-579/13-

En el presente trabajo se analiza la obligaci��n de investigar graves violaciones de Derechos Humanos y Derecho Internacional Humanitario, a la luz de la sentencia de la Corte Constitucional Colombiana referente a la constitucionalidad del Marco Jur��dico para la paz. De la aparente remisi��n que hace la Corte Constitucional a la Corte Interamericana de Derechos Humanos sobre el deber de investigar graves violaciones de Derechos Humanos y de Derecho Internacional Humanitario se concluye que la Corte Constitucional propone como premisa mayor una obligaci��n que surge de una interpretaci��n extensiva de la Convenci��n Interamericana. De la misma forma, se estudia el tratamiento indebido del derecho aplicable a las amnist��as e indultos, que se relaciona con la necesidad de evitar cualquier tipo de impunidad, cuyo concepto sirve para esclarecer cu��les son los est��ndares que se quiere proteger. Por ��ltimo, se analiza el contexto al que se pretende aplicar dicha obligaci��n, es decir, la justicia transicional, proponiendo un modelo interpretativo de los fines de la pena, y su aplicaci��n por medio de la favorabilidad penal, para la justicia transicional, que sea acorde a la interpretaci��n de la Convenci��n Interamericana.

El Outsourcing en la din��mica de sistemas hacia mercados extranjeros

Este trabajo recopila literatura acad��mica relevante sobre estrategias de entrada y metodolog��as para la toma de decisi��n sobre la contrataci��n de servicios de Outsourcing para el caso de empresas que planean expandirse hacia mercados extranjeros. La manera en que una empresa planifica su entrada a un mercado extranjero, y realiza la consideraci��n y evaluaci��n de informaci��n relevante y el dise��o de la estrategia, determina el ��xito o no de la misma. De otro lado, las metodolog��as consideradas se concentran en el nivel estrat��gico de la pir��mide organizacional. Se parte de m��todos simples para llegar a aquellos basados en la Teor��a de Decisi��n Multicriterio, tanto individuales como h��bridos. Finalmente, se presenta la Din��mica de Sistemas como herramienta valiosa en el proceso, por cuanto puede combinarse con m��todos multicriterio.

El principio de colaboraci��n arm��nica, ��pticas, problem��tica y posibles soluciones a los conflictos

Esta investigaci��n estudia de forma general el principio de colaboraci��n arm��nica entre poderes, explora las bases te��ricas que sustentan dicho principio constitucional, analiza las distintas ��pticas jurisprudenciales construidas a partir de las sentencias de la Corte Constitucional y del Consejo de Estado, y adem��s abarca la problem��tica del principio de colaboraci��n arm��nica en el contexto colombiano, con el objeto de proponer soluciones para mejorar la aplicaci��n del principio de colaboraci��n arm��nica. Con este escrito se pretende resolver las siguientes preguntas: ��existe una base jurisprudencial sobre la cual se sustente el principio de colaboraci��n arm��nica? ��Se aplica este principio de forma efectiva en el Estado colombiano? ��Qu�� alternativas permiten aplicar de forma efectiva dicho principio? ��Existen mecanismos alternativos de soluci��n de conflictos que puedan ayudar a mejorar la aplicaci��n de este postulado?

Perfil log��stico del sector cemento en Colombia

Este proyecto caracteriza la log��stica 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 informaci��n log��stica relevante para la producci��n de cemento en Colombia. Esta informaci��n se obtuvo sintetizando estudios y reportes acerca de las pr��cticas log��sticas y las condiciones en las que ��stas se desarrollan. Adicionalmente se realizaron visitas empresariales en diferentes plantas de producci��n de cemento y entrevistas semiestructuradas a expertos en log��stica de los diferentes eslabones. Con la informaci��n primaria y secundaria se caracteriza del producto, las materias primas e insumos necesarios para la producci��n de cemento. Se identifican los principales agentes que componen el sector y se describen los procesos log��sticos relacionados con el cemento en cada uno de ellos. Para las cementeras y canteras se hace un an��lisis de entradas y salidas de los procesos principales de su cadena de valor. Adicionalmente se expone la operaci��n de transporte como un elemento clave en el sector y se presentan las simulaciones de fletes, rutas y cubicaje. Por ��ltimo, se incluye un caso de optimizaci��n de transporte aplicando teor��as de investigaci��n de operaciones.

The crime kuznets curve

We document the existence of a Crime Kuznets Curve in US states since the 1970s. As income levels have risen, crime has followed an inverted U-shaped pattern, first increasing and then dropping. The Crime Kuznets Curve is not explained by income inequality. In fact, we show that during the sample period inequality has risen monotonically with income, ruling out the traditional Kuznets Curve. Our finding is robust to adding a large set of controls that are used in the literature to explain the incidence of crime, as well as to controlling for state and year fixed effects. The Curve is also revealed in nonparametric specifications. The Crime Kuznets Curve exists for property crime and for some categories of violent crime.

Movimientos sociales su construcci��n narrativa desde los nuevos medios: los Indignados bogotanos en Twitter

Se analiza la relaci��n entre movimientos sociales y nuevos medios en Colombia, preguntando en particular por las posibilidades narrativas que tienen los movimientos sociales en el nuevo espacio comunicativo abierto por internet. Para ello, se lleva a cabo un estudio descriptivo del relato elaborado en la red social Twitter por activistas virtuales del movimiento de indignaci��n surgido en Bogot�� tras la destituci��n del alcalde mayor, Gustavo Petro, a finales de 2013. Se encontr�� que Twitter fue un espacio esencialmente de disputa. El relato del movimiento fue construido en permanente contrapunteo no solo con las informaciones de los medios de comunicaci��n tradicionales y las intervenciones de los l��deres pol��ticos, sino tambi��n con expresiones ciudadanas rivales, que se movilizaron paralelamente en la misma red social en un ejercicio de contestaci��n. Esta investigaci��n emplea como marco anal��tico la ���autocomunicaci��n de masas��� propuesta por Manuel Castells.