Utvikling og verifisering av metoder for reologisk karakterisering av materialer for prosessindustrien

Process control, product quality and process design are continuously demanding new sensors and devices that can assess the rheological behavior of fluid and solid products. The need for more methods comes because of three main reasons: (1) there is no single instrument able to perform all the types of rheological characterizations that are needed in the industries, (2) there is no instrument able to characterize all types of fluids and solids, and (3) the complex rheological behavior of many process materials depends upon time, shear, stress, temperature, pressure and process history that restricts the validity of results when for example retrieving information to the process. The aim of this work was to develop two rheological instruments made for different purposes and verify their working and measurement principle. The first instrument is a screw type process rheometer that can handle fluid and semi-solid materials. The second instrument is a die compaction rig that is able to characterize powders. Paper I focuses on an experimental calibration procedure to allow the screw type rheometer to measure the apparent viscosity of fluids using torque as a measurement of an average shear stress and the rotational speed as a measurement of a mean shear rate. From a first prototype, it was possible to predict viscosity with maximum errors or residuals smaller than 25 Pa s over a range of viscosities (35-450 Pa s) using a Newtonian standard fluid. The use of a dry sliding bearing created a friction in the system that resulted in flow curves having an intercept different than zero when using a Newtonian standard fluid. This encouraged the creation of another calibration method in Paper II that considers an intercept different to zero by using the area below the curve. Measurements of downstream pressure were included in Paper II as an alternative to the torque measurements. The flow curve formed between downstream pressure and rotational speed resulted in a linear curve with intercept zero when using the Newtonian standard fluid. Time variations in pressure and torque were also studied since they could affect the measurements. The variations became more notorious (e.g. increased amplitude of torque and pressure oscillations) at higher resistances to flow produced by either an increased viscosity or to a lesser extent by reductions in die diameter (a downstream restriction). The distribution of errors in Paper II was calculated through the root mean square error of prediction (RMSEP). The calibration model based on the area below the curve presented the significantly smallest (p < 0.005) RMSEP of 2.2 Pa s. All other models were not significantly different; however they varied from ± 3.7 Pa s up to ± 12 Pa s. The calibration methods presented in Paper I and II to predict an apparent viscosity were based on the ratio torque – speed or downstream pressure – speed that was not needed to convert torque or downstream pressure into a shear stress unit or speed to a shear rate unit. For this reason Paper III studied the use of a coaxial cylindrical analogue to represent the geometrically complex screw. A replicate of the screw type rheometer with some modification of the recirculation system was assembled in a Paar Physica UDS 200 rheometer to take advantage of the low friction provided by its air bearing. The aim was also to have an insight to how a screw type rheometer could perform viscoelastic measurements in oscillation. The flow curves using non-Newtonian fluids, both time independent and time dependent, were closer to the flow curves obtained with cone-plate, plate-plate and bob-cup than to the ones obtained from a standard Paar Physica impeller. The storage and loss modulus from the screw rheometer were of relatively similar magnitude to the ones obtained from plate-plate and bob-cup systems. The good results also make this replicate an attractive set-up for laboratory use. Paper IV and V were done using a third prototype (2nd measurement principle) which is a laboratory die pelleting or compressing rig that presses powders under pre-determined load and speed to form cylindrical compacts (or pellets) of different densities. Paper IV investigates the compression rheology of ground Scots pine (Pinus sylvestris) pre-handled with different storage times and drying temperatures. The physical strength of the pellets formed in the laboratory die pelleting rig was also investigated. Ground Scots presented a ductile compression and the pellets resulted to be plastic and ductile. The highest drying temperature and longest storage time, produced pellets with the highest strength values under diametrical compression test. Paper V uses the laboratory die pelleting rig to compare the yield stress measured in a stress relaxation test and the normal stress at incipient flow of Scots pine with the energy consumption of an industrial pellet press. The results show that normal stresses at incipient flow and yield stresses are linked to the energy consumed by an industrial pellet press. Long storage time of the raw material produced higher normal stresses at incipient flow and higher yield stresses in the materials. Most probably this is the cause for the higher energy consumption in the industrial pellet press. Drying temperature did not change incipient flow and normal stresses significantly.Det er et stadig behov for å utvikle nye metoder og nytt utstyr for å karakterisere de reologiske egenskaper til faste og flytende produkter med tanke på prosesskontroll, prosessoptimalisering og optimering av produktkvalitet. Det finnes ikke noe enkelt instrument som kan gjøre en fullstendig karakterisering som tilfredsstiller behovene fra alle typer industri. Det finnes ikke noe enkelt instrument som kan karakterisere alle typer fluider og faste stoffer, og for mange materialer endres de reologiske egenskapene som funksjon av tid, temperatur, skjær, stress, trykk og historikk, noe som gjør at innhenting av tidligere målte data kan forårsake feil. Målet med dette arbeidet var derfor å utvikle og verifisere nye instrumenter for karakterisering av reologiske egenskaper. To instrumenter ble utviklet, et skruetype reometer for karakterisering av flytende og halvfaste materialer og et som baserte seg på pressing av materiale gjennom en dyse beregnet for pulver (fast stoff). Artikkel I fokuserer på den eksperimentelle kalibreringsprosedyren for et skruetype reometer når det brukes til å måle den tilsynelatende viskositet i væsker ved hjelp av dreiemoment, som mål på en gjennomsnittlig skjærspenning, og rotasjonshastigheten, som et mål på en gjennomsnittlig skjærhastighet. Fra en første prototype var det mulig å forutsi viskositet med maksimal feil mindre enn 25 Pa s i viskositetsområdet 35-450 Pa s ved hjelp av en Newtonsk standard væske. Bruken av et tørt glidelager gav en friksjon i systemet som resulterte i at kurver (dreiemoment versus rotasjonshastighet) ikke passerte gjennom origo ved bruk av en standard Newtonsk væske. Dette oppmuntret til etablering av en annen kalibreringsmetode i Artikkel II som vurderer et skjæringspunkt forskjellig fra null ved hjelp av området under kurven. Målinger av nedstrøms trykk var inkludert i Artikkel II som et alternativ til dreiemoment målingene. Flytkurven dannet mellom nedstrøms trykk og rotasjonshastighet resulterte i en lineær kurve gjennom origo ved bruk av en standard Newtonsk væske. Tidsvariasjoner i trykk og moment ble også studert siden de kunne påvirke målingene. Variasjonene ble mer dominerende (f.eks. økt amplitude av moment og trykk svingninger) ved høyere strømningsmotstand forårsaket av enten en økt viskositet eller i mindre grad av reduksjoner i dyse diameter (en nedstrøms begrensning). Fordelingen av prediksjonsfeil i Artikkel II ble beregnet ved bruk av RMSEP (Root Mean Square Error of Prediction). Kalibreringsmodellen basert på arealet under kurven presenterte signifikant minste (p <0.005) RMSEP på 2.2 Pa s. Alle andre modeller var ikke signifikant forskjellige, men de varierte fra ± 3.7 Pa s opp til ± 12 Pa s. Kalibreringsmetodene som presenteres i Artikkel I og II til å forutsi en tilsynelatende viskositet var basert på forholdet dreiemoment - hastighet eller nedstrøms trykk – roterende hastighet slik at det ikke var nødvendig å konvertere dreiemoment eller nedstrøms trykk til en skjærspenning eller farten til en skjærhastighet. Av denne grunn studerte Artikkel III bruken av en koaksial sylindrisk analog til å representere den geometrisk komplekse skruen. En replika av skruetype reometeret, med noen endringer i resirkuleringssystemet, ble montert i et Paar Physica UDS 200 reometer for å dra nytte av den lave friksjonen i luftlageret til dette instrumentet. Målet var også å få en innsikt i hvordan et skruetype reometer kunne utføre viskoelastiske målinger i oscillasjon. Strømningskurvene for ikke-newtonske væsker, både tidsuavhengige og tidsavhengige, var nærmere strømningskurvene oppnådd med kon-plate, plate-plate og konsentriske sylindere enn de man fikk ved bruk av en standard Paar Physica impeller. Lagringsmodul og tapsmodul fra skruereometeret var av forholdsvis samme størrelsesorden som verdier hentet fra plate-plate og konsentriske sylinder systemer. De gode resultatene gjør også at dette er et attraktiv oppsett for laboratoriebruk. Artikkel IV og V ble gjort ved hjelp av en tredje prototype (andre måleprinsipp) som består av en komprimerings rigg som presser pulver ut gjennom en dyse under forhåndsbestemt belastning og hastighet for å danne sylindriske komprimerte elementer (pellets) med forskjellige tettheter. Artikkel IV undersøker komprimeringsreologi av oppmalt furu (Pinus sylvestris) forbehandlet med ulik lagringstid og tørketemperaturer. Den fysiske styrken til pellet dannet med komprimeringsriggen ble også undersøkt. Oppmalt furu gav en seig komprimering og de produserte pelletene var plastiske og duktile. Den høyeste tørketemperatur og lengste lagringstid, produserte pellet med høyest styrke ved diametral kompresjonstesting. Artikkel V bruker kompresjonsriggen med dyse pelletering for å sammenligne materialets flytspenning målt i en spennings relaksasjonstest og normalspenningen ved begynnende strømning av furu med energiforbruket til en industriell pelletpresse som arbeider med samme materiale. Resultatene viser at normalspenninger ved begynnende strømning og flytspenning er relatert til energien som forbrukes av en industriell pelletpresse. Lang lagringstid av råstoff produserte høyere normalspenninger ved begynnende strømning og høyere flytspenninger i materialet. Mest sannsynlig er dette årsaken til det høye energiforbruket i industrielle pelletpresser. Tørketemperaturen påvirket ikke initiell strømning og målte normalspenninger i særlig grad

El sorprendente viaje interdisciplinar de un cuadrado negro. Pintura y cine

It does not fit doubt that the most known and representative creation of the Russian artist Kazimir Malevich, Black Square, is, at the same time, one of the most polemic, misunderstood and enigmatic works of the contemporary art. It calls the attention how a formal painting and plastically so simple it could have generated rivers of ink throughout the last century. Nevertheless, taking the risk of seeming to incur a new exaggeration, we dare to affirm that much less everything is not even said on the quintessence of the suprematism. The interdisciplinary running that it has made the above mentioned work throughout the last century, going on from the painting to the cinema and from the cinema to the painting, is a very suggestive topic that we can use as an example of the moment when estimating the important iconographic legacy which supposed for some people the clear sign of a foreseen lack of resources of the suprematist abstraction. The methodology followed in this work is essentially formalist.No cabe duda de que la creación más conocida y representativa del artista ruso Kazimir Malevich, Cuadrado negro, es, al mismo tiempo, una de las obras más polémicas, incomprendidas y enigmáticas del arte contemporáneo. Llama la atención cómo una pintura formal y plásticamente tan simple ha podido generar ríos de tinta a lo largo del último siglo. No obstante, y aún a riesgo de parecer incurrir en una nueva exageración, nos atrevemos a afirmar que ni mucho menos todo está dicho sobre la quintaesencia del suprematismo. El curioso recorrido interdisciplinar que ha venido realizando dicha obra a lo largo de la última centuria, pasando de la pintura al cine y del cine a la pintura, se nos antoja un tema muy sugerente que bien puede servir de ejemplo a la hora de apreciar el importante legado iconográfico de lo que para algunos no fue más que el síntoma inequívoco del previsible agotamiento de la abstracción suprematista. La metodología seguida en este trabajo es esencialmente formalista

Ignacio Álvarez Castelao: Housing developments for power station workers

[ES] Este artículo define cuatro de los trece poblados para trabajadores que proyecta Ignacio Álvarez Castelao en el norte de España, para la empresa eléctrica Electra de Viesgo, entre 1948 y 1965: Puente de San Miguel, Santander; Aguilar de Campoo, Palencia; Soto de Ribera, Oviedo y Santa María de Garoña, Burgos. El artículo analiza la base teórica que desarrolla el arquitecto a mediados de los años 50 para su construcción, basada en la modulación, la prefabricación y la sistematización de los elementos constructivos para agilizar su construcción en el medio rural. Se analiza sistemáticamente el espacio público, la vivienda y el mobiliario, al mismo tiempo que las transiciones entre las diferentes escalas que realiza Castelao, desde la escala geográfica del urbanismo, hasta la arquitectura y el mobiliario. En esencia, se estudian aquellos elementos de arquitectura que proyecta Castelao para hacer unos poblados ordenados y, con buenas condiciones de habitabilidad y confort para los trabajadores, tanto dentro, como fuera de las viviendas.[EN] This article analyses four of the thirteen housing developments for workers that were designed in northern Spain for the Electra de Viesgo electricity company by Ignacio Álvarez Castelao between 1948 and 1965, namely those constructed in Puente de San Miguel in Santander, Aguilar de Campoo in Palencia, Soto de Ribera in Oviedo, and Santa María de Garoña in Burgos. We analyse the theoretical foundations Castelao developed in the mid-1950s to construct these four residential complexes, which were based on modulation, prefabrication and the systematisation of constructive elements in order to streamline their construction in the rural environment. Also systematically analysed in this paper are the public spaces, the housing, the furniture, and the transitions Castelao introduced between the various scales, from the geographical urban planning scale to architecture and furniture. In essence, we study the elements of architecture Castelao designed to create orderly housing developments with comfortable habitability conditions for the workers both inside and outside their homes.Gonzalvo Salas, C. (2020). Ignacio Álvarez Castelao: Poblados para trabajadores de centrales eléctricas. VLC arquitectura. Research Journal. 7(2):185-214. https://doi.org/10.4995/vlc.2020.11354OJS18521472Arancón Álvarez, Gerardo. "Viviendas de la Eléctrica de Aguilar de Campoo." In Arquitectura Moderna en Asturias, Galicia, Castilla y León. Ortodoxias, márgenes y transgresiones, coordinated by Celestino García Braña and Fernando Agrasar Quiroga. A Coruña: Colegio Oficial de Arquitectos de Galicia, 1998.Azpilicueta, Enrique. "La Construcción de la Arquitectura de Postguerra en España (1939-1962)." PhD diss., Universidad Politécnica de Madrid, 2004.Ayuso, Francisco. La transformación urbano-industrial del Concejo de Ribera de Arriba: Políticas paternalistas de la Central Térmica de Soto de Ribera (1959-1971). Oviedo: Universidad de Oviedo, 2013.Álvarez Castelao, Ignacio. "Viviendas para el personal de una central eléctrica." Arquitectura, no. 74 (1965).Álvarez Castelao, Ignacio. "Concurso de viviendas experimentales del Instituto Nacional de la Vivienda." Últimos Avances Técnicos en Edificación, no. 39 (1958).Álvarez Castelao, Ignacio. "Proyecto de grupo de viviendas para S.A. Electra de Viesgo en Puente de San Miguel (Santander)." Box 175.598/18. Asturias Historical Archive (AHA). Official College of Architects of Asturias.Álvarez Castelao, Ignacio. "Proyecto de viviendas subvencionadas para Electra de Viesgo, S.A. en Aguilar de Campoo, Palencia." Box 175.607/14-15. Asturias Historical Archive (AHA). Official College of Architects of Asturias.Álvarez Castelao, Ignacio. "Proyecto de edificios para residencia y viviendas de Nuclenor en Santa María de Garoña, Burgos." Box 175.609/09. Asturias Historical Archive (AHA). Official College of Architects of Asturias.Capitel, Antón. "Modernidad y clasicismo. El siglo XX en Asturias a través de cuatro personajes." Arquitectura Viva, no. 132 (2010).García Braña, Celestino. "Vivienda y gestión pública." In Vivienda pública en Asturias (1982-2002), coordinated by María Fernanda Fernández Gutiérrez. Oviedo: Consejería de Infraestructuras y Política Territorial del Principado de Asturias, 2003.García Braña, Celestino. Introduction to Arquitectura Moderna en Asturias, Galicia, Castilla y León. Ortodoxias, márgenes y transgresiones, coordinated by Celestino García Braña and Fernando Agrasar Quiroga. A Coruña: Colegio Oficial de Arquitectos de Galicia, 1998.Iberduero. Nuclenor. Santander: Iberduero, 1971.Sambricio, Carlos. "Contemporaneidad vs. modernidad. El concurso de vivienda experimental de 1956." In La vivienda experimental: Concurso de Viviendas Experimentales de 1956, coordinated by Fundación Cultural COAM. Madrid: COAM, 1997.Sendín García, Manuel Ángel. "Producción y distribución de energía eléctrica en Asturias." Ería, no. 17 (1989).Sierra Álvarez, José. El obrero soñado. Ensayo sobre el paternalismo industrial (Asturias, 1860-1917). Madrid: Siglo Veintiuno de España Editores, S.A., 1990.Tielve García, Natalia. Arquitectura moderna en la central de Soto de Ribera: La obra de Ignacio Álvarez Castelao y Carlos Fernández Casado. Oviedo: Cicees-Incuna, 2009

Reclaiming Craftsmanship

In upcoming years, many institutions in the private and public sectors will lose valuable organizational knowledge due to organizational restructuring, departmental consolidation, retirements and attrition. This can have a potentially crippling effect on organizational effectiveness and service delivery. Organizations need to establish processes and develop tools that allow them to capture employees know-how-and-know-what, and disseminate that information and knowledge to other employees. In the age of the digital economy, the temptation appears to be to introduce technology to capture codifiable data, resulting in the inadvertent undervaluing of the personal knowledge and expertise accumulated by their employees over many years of practical experience. My focus is on personal knowledge, particularly concerning acquisition and transmission. Approaching the research from a post-positivist as well as a pragmatist approach, I have sought to identify and understand the factors that influence people to share knowledge and conversely how people learn from others, through mentoring for example. Within this context, I advocate for the return to the spirit of craftsmanship and reclaim the ideas of learning by doing, having more human-to-human connections to learn from, and taking the time to be engaged in mastering a practice. My goal has been to question rather than to pursue a definite explanation for how the acquisition and transmission of personal knowledge unfolds. As a pragmatist, I approach the idea of knowledge as a derivative of our engagement and active experience with the world. To this end, I added an applied element to this dissertation; I have included a working prototype of a platform for people to share their skills and interact with others in their network. This software application also acts as a repository of data for my research and for topics related to personal knowledge. For example, it includes an Alphabet of Personal Knowledge wherein I briefly examine the etymology and use of selected words in the context of knowledge acquisition and sharing. My interest lies in using multi-dimensional methods that complement each other with the express goal of creating new knowledge that can in turn be used to improve mentoring and knowledge sharing programs

Aprendiendo a verbalizar

Treball final de Grau en Mestre o Mestra d'Educació Infantil. Codi: MI1040. Curs acadèmic 2016-2017A continuación, se expone el Trabajo Final de Grado que aborda, principalmente, la relevancia de la estimulación del lenguaje oral en el segundo ciclo de Educación Infantil. También pretende acercarse a una clara definición del concepto teórico del lenguaje oral, a través de diversas teorías de adquisición y de desarrollo del mismo. En segundo lugar, a partir del marco teórico, se ha llevado a cabo una propuesta metodológica con la intención de trabajar, desde las tres áreas de la educación infantil, el desarrollo y adquisición de la lengua oral en alumnos de 3-4 años, comprobando, a su vez, el nivel de lenguaje adquirido que tienen en función de su edad y las dificultades que presentan a la hora de expresarse oralmente. De este modo, también se contrasta que el lenguaje es una de las principales herramientas del pensamiento, siendo el eje vertebrador sobre el que se han de construir el resto de aprendizajes, como afirman los autores citados. Es una propuesta metodológica que gira en torno a 7 actividades donde la función y la actitud del maestro es más que relevante y, por lo tanto, un condicionante para los alumnos. Los resultados obtenidos nos muestran si las actividades planteadas son las adecuadas para cumplir este cometido, comentando en el apartado de conclusiones, las singularidades de cada actividad.Then presents the final degree work which deals mainly with the relevance of the stimulation of the oral language in the second cycle of early childhood education. It also aims to reach a clear definition of the theoretical concept of the oral language, through various theories of acquisition anddevelopment. Second, starting from the theoretical framework, has carried out a methodological proposal with the intention of working, from three areas of early childhood education, development and acquisition of the oral language in pupils of 3-4 years, checking, at the same time, the level of acquired language that have depending on their age and the difficulties presented when it comes to express orally. In this way, also contrasts that language is one of the main tools of thought, being the backbone on which are built the rest of learning, as the cited authors. Is a methodology that revolves around 7 activities where function and the attitude of the teacher is more than relevant and, therefore, a conditioning factor for the students. The results show us if raised activities are suited to this role, commenting on the conclusions, the singularities of each activity section

Cambio técnico en la industria del automóvil en España (1983-1992).Un estudio de caso

El trabajo contribuye al estudio de la industria del automóvil en España con la estimación de una función de producción que resume la tecnología de una planta de montaje de automóviles perteneciente a un grupo multinacional, en los primeros años de su funcionamiento. Los resultados muestran estimaciones de los parámetros de la función de producción y, entre ellos, de la tasa media acumulativa de crecimiento en la productividad total de los factores o progreso técnico no incorporado. Aunque la historia del automóvil en España incluye frecuentes referencias a la productividad como indicador de eficiencia productiva, en todos los casos se trata de la productividad aparente del trabajo que solo se aproxima el progreso técnico en condiciones muy particulares. Los resultados obtenidos sugieren otras razones, además de los bajos costes laborales, como ventajas comparativas del automóvil en España