This work is a preliminary attempt to study the effect between thermal shock and abrasive wear in WC-Co alloys. This was done by evaluating the thermal shock resistance of a WC-12wt%Co mining grade as a function of temperature, number of thermal shock cycles and making comparisons between the abrasive wear responses of samples subjected to thermal shock and samples not subjected to thermal shock. A furnace was designed for the thermal shock treatments. Abrasive wear tests were performed on a 2-body sliding wear apparatus using 80-grit SiC abrasive paper as a counter-face. Stereo and electron microscopy as well as microprobe techniques were used to analyse the effects of thermal shock. It is confirmed that thermal shock has a negative effect on the wear rate of WC-12wt%Co. The results showed an initial high mass loss rate during abrasive wear testing, which increased with increasing temperature and a decrease in wear rate with time until the wear rates converged for all samples. The surface analysis after thermal shock indicated voids on and below the surface, stained surfaces, a thin oxide layer and the possibility of WC decarburization which accelerated the wear response.

MSc (Physiotherapy), Faculty of Health Sciences, University of the Witwatersrand / In South Africa, the concept of Developmental Co-ordination Disorder (DCD) is relatively unfamiliar and not well understood. The exact epidemiology is unknown, but the Diagnostic and Statistical Manual of Mental Disorders (DSM IV, 2000) indicate that the value could be between five and ten percent of the American population. Many studies on DCD have been conducted and most highlight the immense difficulties these children experience with motor activities, both in sport and daily tasks. However, few studies specifically investigated endurance and the impact it has on the child’s ability to function normally without too much effort and fatigue due to the condition. The main aim of this study was to determine the difference in submaximal endurance levels between children diagnosed with DCD and normally developing children. Children between the ages of seven and ten years were included in the study. The Six Minute Walk Test (6MWT) was employed to determine the average distance covered by each of two groups that were selected to participate in the study and thus, the submaximal endurance levels of each group. The first group of participants consisted of children having a diagnosis of DCD (n=31) and the second comparative group consisted of normally developing children (n=17). The results were analysed and compared using the Student t-test. Anthropometric data of height, age, gender and weight as well as baseline data of breathing rate, heart rate and peak flow were taken. These were compared to normative data as determined by the growth charts of the Centre for Disease Control and Prevention (CDC) as well as previous research on the various topics. The average distance covered by the DCD group was 375.89 metres with a standard deviation of ±73.33 and the mean distance covered by the normal comparative group was 430.48 metres with a standard deviation of ±60.85. When the two groups were compared it produced a p-value of 0.0086 which was a statistically significant difference. The normally developing group covered on average 54.6 metres more distance than the group with co-ordination difficulties. In comparison to studies that determined normal age (Lammers et al, 2008) and height (Li et al, 2007) reference values, the children within the eight-year age band for the normally developing group fell within the determined values. The other age bands fell below average for both the DCD and normally developing groups. The finding of the current study is important as it highlights the discrepancy in the submaximal endurance levels of children with DCD when compared to normally developing children of the same age. This is important when considering that most of the activities of daily living are performed at submaximal endurance levels and it is particularly important to note that these are the activities that children with DCD find challenging. The 6MWT can be performed by children as young as four years of age, with explanation and encouragement. This is particularly helpful in the clinical setting, as other tests of physical fitness require more time, equipment and generally good co-ordination in the individual being tested. The 6MWT is easy to apply and requires few tools, making it a cost and time effective means of testing submaximal fitness in children. It is thus a useful measure to determine whether therapeutic intervention has impacted endurance for activities of daily living.

Au cours de la dernière décennie, les technologies de l'information et de la communication intégrées aux produits de consommation ont considérablement modifié la nature de leurs usages. Réactives, les entreprises se sont emparées de ces nouvelles technologies et proposent aux consommateurs de customiser leurs produits quotidiens après achat. J’ai intitulé cette approche "Smart Customization", dans ma thèse. L´idée étant que, pour qu'une telle customisation "intelligente" ait lieu, il faut intégrer directement des boîtes à outils intelligentes (ou smart UTCD) dans nos produits de consommation. Ces boites à outils intelligentes sont ensuite destinées à guider les consommateurs dans le procédé de customisation de leurs objets. Actuellement, il n’y a pas véritablement de recherche académique alors que, au contraire, la presse industrielle évoque la smart customization comme une opportunité à exploiter. Il semble pourtant essentiel, d'identifier les facteurs de succès de ces nouvelles offres de customisation, notamment, en adoptant le point de vue du consommateur sur l´élément principal Smart UTCD. C´est ce qui a déterminé l´objectif de ma thèse. Via une étude d´acceptante technologique dans le papier 1, un choice-based conjoint analysis dans l’article 2 et une exploration des mécanismes de co-conception qui ont lieu entre le consommateur et l´outil de conception « smart UTCD », je participe à la recherche sur la smart customisation. / In the last decade, our products have been more and more equipped with information and communication technology (ICT), which has modified the nature of their applications greatly. Notably, firms find finally a mean to empower customers to customize their products after purchase. One talks about “Smart Customization”. For such “smart” customization to happen, the idea is to embed directly smart user toolkits for co-design (smart UTCD) into our consumer products. That said, while in the business press, they largely view smart customization as an opportunity to be tapped, in contrast, research is hardly focused on it. Notably, it appears essential to identify factors of customer - based success of such novel customization offers. Thereby, in paper I, I adapt and test a technology acceptance model to smart UTCD. In paper II, I realize a choice based conjoint analysis on smart UTCD. In article III, I expose a theoretical framework for use generation and apply it one the two existing types of smart UTCD. With my findings, I contribute to theory by adding to our limited understanding of the smart UTCD acceptance, providing in-depth knowledge on the customer´s choice process on the smart UTCD´ design features and by opening the black box on the co-design mechanisms that occur between customers - smart UTCD. Additionally, the findings of my three article that compose my dissertation permit firms to be provided with some measures on how to design smart customization offers that fit better the target customers.

Nanotubular titanates were synthesized by a simple methodology using a commercial TiO2 (Degussa P25 containing anatase and rutile phases) and a base (KOH) solution. Prior to the removal of KOH, the samples of TiO2 were aged for three different time intervals (0, 2 days, 61 days). The freshly prepared synthetic samples were characterized for their structural and morphological properties by BET, XRD, Raman, TEM, HRTEM, EDX and SEM. Both TEM and SEM analysis revealed that ageing time influenced the tubular structure and morphology of the new materials. Raman and surface analysis data also showed that ageing time affected both the structural and surface properties of TiO2. The XRD results showed that the crystallinity of the TiO2 decreased with increasing ageing time. Energy dispersive Xray spectroscopy (EDX) showed that the tubes derived from TiO2 are comprised of potassium, titanium and oxygen. Catalysts A, B and C were prepared by the addition of 1 wt% Pd (wet impregnation) to the titanate formed after ageing of the TiO2 in KOH for 0, 2 and 61 days, respectively. The catalysts were tested for the vapour phase hydrogenation of phenol in a fixed-bed micro reactor within the temperature range of 165 to 300oC under atmospheric pressure. Of the three catalysts, catalyst B showed the best activity (conversion 97%) and total selectivity to cyclohexanone (99%). In contrast, catalyst C, which showed a moderate activity favoured selectivity to cyclohexanol. These results are attributed to differences in surface morphologies between the two catalysts B and C, associated with the surface area and a change in the surface acid-base properties. Catalyst B also showed a higher resistance towards deactivation and maintained a higher total selectivity to cyclohexanone than did catalyst C. A hydrothermal treatment of NaOH and TiO2 was employed to prepare two materials, TiO2-B and TiO2-C with relatively small crystallite size and large specific surface area. The hydrogenation of phenol was used to evaluate the activity of the catalysts Pd/TiO2-B and Pd/TiO2-C. The reaction proceeds in a single step and involves the formation of a partially hydrogenated product, namely cyclohexanone. The larger surface area catalyst (Pd/TiO2-C, 89 m2/g) showed better activity and selectivity to cyclohexanone than its counterpart (Pd/TiO2-B, 45 m2/g). The catalyst activity showed significant dependency on the surface area whereas the selectivity was greatly influenced by surface basicity. Titania derived nanotubes synthesized by treating P25 Degussa TiO2 with a concentrated KOH solution and aged for 2 days was used as a catalyst support for the hydrogenation of o-chloronitrobenzene (O-CNB) with Pd as the active phase. The vapour-phase hydrogenation of O-CNB was carried out in ethanol at 250 oC and atmospheric pressure over a Pd/TiO2 derived nanotube catalyst (Pd/TiO2-M). Pd/TiO2-M gave complete conversion (100%) of O-CNB with a selectivity to orthochloroaniline (O-CAN) of 86 %. The stability of the Pd/TiO2 catalyst was tested over 5 hours during which time the conversion slowly dropped to 80 % (selectivity 93 %) due to poisoning. TPR analysis revealed the existence of a strong palladium-support interaction and this was found to be crucial to the overall activity of the catalyst. It has been found that gold supported on potassium titanate, KTiO2(OH) can, under some circumstances, exhibit a superior performance for the oxidation of carbon monoxide, relative to that obtained with titania as a support. It appears that the dispersions of gold on the two types of support are sufficiently similar that other factors are responsible for the improved activity noted. It may be that the higher basic character and detailed structural features of the titanate surface play a role. The effect of the addition of alkali metal ions on the anatase to rutile transformation of titanium dioxide (P25 Degussa) was investigated using X-ray diffraction, Raman spectroscopy, and surface area measurements. Both Li and Cs ions accelerated the anatase to rutile transformation whereas Na and K ions did not show any effect. Furthermore, the effect was more pronounced after addition of the Li ions so that the transformation temperature dramatically decreased from ~800 oC for commercial TiO2 to ~600 oC. The surface area of the TiO2 material decreased with sintering due to the increase in crystalline size. Moreover, the acceleration of the transformation occurred at lower temperatures and at higher Li content. Mesoporous nanocrystalline TiO2 (HSA TiO2) was prepared by hydrothermal treatment of TiO2 with NaOH. The material was very amorphous and underwent the phase transformation from amorphous to anatase phase and subsequently from anatase to rutile phase with sintering. The anatase to rutile transformation was delayed after doping and grain growth was inhibited. After sintering at 800 oC the material (HSA TiO2) still contained a significant amount of the anatase phase. The complete transformation only occurred at ~1000 oC. The esterification of benzoic acid and butyric acid with propanol over alkali metal ions supported on TiO2 was investigated. K/TiO2-D showed the highest conversion for both benzoic acid and butyric acid. The selectivity to propylbenzoate and propylbutyrate was influenced by the basic nature of the catalysts. Butyric acid was found to be more reactive than benzoic acid. The difference in reactivity was explained in terms of steric and inductive effects. The differences in boiling points and pH values were also considered.

O presente trabalho apresenta um estudo sistemático sobre a adsorção e a eletrooxidação do CO sobre eletrodos monocristalinos de platina. A partir da análise das intensidades das bandas integradas e das freqüências do Pt(111)-CO, apresenta-se uma interpretação dos efeitos de acoplamento dipolo-dipolo e de interconversão do COads.. Assim, sobre a Pt(111) os espectros de FTIR in situ mostram que o aumento na razão da intensidade das bandas integradas ACOB/ACOL e nas freqüências do νCOB quando θCO,total diminue é devido à redução do acoplamento dipolo-dipolo entre as moléculas do CO em diferentes sítios e, adicionalmente, à interconversão das formas inclinadas dos COL e COB para a forma do COB. No sentido de explicar esta interconversão, propomos um mechanism baseado nas interações dos orbitais de fronteiras do CO e do metal, associado com a retrodoação de elétrons. Nesse modelo, os deslocamentos das formas inclinadas do COL e do COB em direção à forma do COB são favoráveis provavelmente porque a retrodoação de elétrons, Ptd → CO2π* (LUMO), aumenta quando θCO,total diminui. Experimentos potenciostáticos sugerem que a cinética de nucleação e crescimento é o melhor modelo para descrever a eletrooxidação do CO. Propomos que no potencial de oxidação, ECO oxi. pode existir uma via muito rápida de formação do precursores oxigenados e que este pode lateralmente colidir com as ilhas de CO, impedindo que ocorra a dissipação das ilhas do COads. no potencial de oxidação, ECO oxi.. Apresentamos a evolução do crescimento e da oxidação de sub-monocamada de CO sobre monocristais de platina facetados. Em baixo grau de recobrimento do CO foi observado que a adsorção dessa molécula ocorre sem ocupação preferencial de sítios quinas ou terraças. Assim, sugerimos que a adsorção é um processo randômico e que depois que as moléculas do CO são adsorvidas estas não apresentam apreciáveis deslocamentos a partir de CO-(111) em direção aos sítios CO-(110). Isto significa que depois da adsorção, as moléculas do CO têm um longo tempo de residência ou que apresentam um coeficiente de difusão muito baixo. Mas, para alto grau de recobrimento por CO, os resultados mostram que é possível que laterais interações desempanham importantes papéis na distribuição de ocupação dos sítios e observamos que durante a eletrooxidação, são liberados simultaneamente sítios quinas e sítios terraços. Quanto à pré-oxidação, foi observado que quatro condições experimentais precisam ser satisfeitas para que ela ocorra sobre os monocristais de platina: (i) alto grau de recobrimento por CO; (ii) que a superfície onde oncorre a oxidação do CO tenha defeitos, como sítios quinas (110); (iii) que a camada do CO seja formada sob potenciais mais negativos do que o potencial de carga total zero do metal; (iv) e que exista pequena quantidade de CO dissolvido. As condições (i) e (ii) precisam ser satisfeitas simultaneamente para promover a pré-oxidação do CO; as condições (iii) e (iv) essencialmente contribuem correspondendo à condição (i). Observamos que a magnitude do pre-pico aumenta com o aumento do grau de recobrimento por CO. Então, isto pode ser indicativo que a pré-oxidação não tem relação com a difusão do CO em superfície porque o aumento do grau de recobrimento reduz a probabilidade de difusão em superfície. O modelo de ilhas comprimidas parece ser mais apropriado para descrever a pré-oxidação do CO. / This work presents a systematic study on the CO adsorption and its oxidation at platinum single crystal electrodes. From analysis of integrated band intensity and band frequency position of the Pt(111)-CO interface in acid, it is presented an interpretation of the dipole-dipole coupling effect and surface site inter-conversions of COads.. Thus, on Pt(111), in situ FTIR data show that the increase in both ratio integrated band intensity ACOB/ACOL and frequency of νCOB when θCO,total reduces it is indicative of reduce in dipole-dipole coupling interactions between CO molecules in different surface active sites and a mechanism where the tilted COL and COB in CO pressed adlayer displace or inter-convert in favor of increase of COB concentration. In order to explain that CO interconversion, we propose a mechanism based in frontier molecular orbitals of CO and the orbitals of the metal associated with the electron back bond donation. Thus, the displacement of tilted COL and COB on the surface towards COB is more stable because probably the back bond electron donation, Ptd → CO2π* (LUMO), increase when θCO,total diminishes. Potentiostatic experiments suggest that the nucleation and growth is the better model to describe the CO oxidation. It is proposed here that close to ECO oxi. might there is a fast pathway toward formation of oxygenated species and it might reach the CO islands by side and this hinder the dissipation of COads. islands at ECO oxi.. We report also time evolution studies of low CO adsorption coverage and oxidative stripping on stepped platinum surfaces. In low CO coverage, it was observed that there is no preferential site occupancy for CO adsorption on step or terrace. It is proposed that CO adsorption onto these surfaces is a random process, and after CO adsorption there is no appreciable shift from CO-(111) to CO-(110) sites. This implies that after adsorption, CO molecules either have a very long residence time, or that the diffusion coefficient is much lower than previously thought. But, in high CO coverage, the results show that it is possible that the lateral interaction might play important role in CO site occupancy and it was observed that during the CO electrooxidation the sites released included both terrace (111) and step (110) orientations. Among the CO oxidation a clear CO preoxidation process also occurs. It was observed four experimental conditions which were verified to be fulfilled to promote CO pre-oxidation on platinum single crystal: (i) the CO coverage is should be higher than minimum threshold; (ii) the surface where CO oxidation take place should have defects, such as (110) steps; (ii) the CO monolayer should be formed at potentials below the potential of zero total charge; (iv) and in a small amount of dissolved CO should be present in the electrolyte solution. In both conditions (i) and (ii) are necessary to take place simultaneously to promote CO pre-oxidation, (iii) and (iv) essentially contribute in fulfilling condition (i). It was verified that the magnitude of pre-peak increases with the amount of CO coverage. Thus, this might indicate that the CO pre-oxidation is not having relationship with the CO diffusion on the surface, because the increase of CO coverage diminishes surface diffusion. A picture model of compressed CO islands seems the most to describe CO pre-oxidation.

Dans la mesure où un système est un ensemble d'éléments en interaction, la difficulté pour un ingénieur système est de guider l’architecture d'un modèle « total » du système en tant qu'ensemble de modèles « locaux » d’ingénieries interdisciplinaires en interaction. Les travaux présentés dans ce mémoire s’intéressent plus précisément à la nature heuristique, spécifiante et exécutable de cette relation « totale » de couplage afin de construire un modèle virtuel du système à faire. La perspective holonique retenue permet de considérer cette relation de couplage de façon descriptive du TOUT et prescriptive de chacune des PARTIES aussi bien en regard de la situation-système à percevoir que des constitutifs-système à architecturer. Ainsi, nous avons revisité cette relation en tant que processus itératif, récursif et collaboratif de co-spécification-système visant à supporter la requête de connaissances auprès de chacune des ingénieries spécialistes délivrant en retour les modèles constitutifs satisfaisant des exigences systèmes. Notre environnement de co-modélisation-système se compose alors d’un ensemble d’environnements élémentaires de modélisation de constituants-système, avec pour objectif de préserver les outils, méthodes et processus de travail de chacune des parties prenantes. La modélisation au niveau système s’appuie sur le langage de modélisation « SysML » pour architecturer l’ensemble des connaissances. La vérification et la validation système s’effectue par co-exécution de modèles autour d’un bus de co-simulation, y compris in-situ avec la plate-forme d’expérimentation CISPI du projet SAFETECH du CRAN constituant notre cas d’application / Insofar as a system is a set of interacting elements, the difficulty for a system engineer is to guide the whole model architecture of a system as a set of interdisciplinary engineering part models interacting. The works presented in this thesis are specifically interested in the heuristic, specifying and executable nature of this whole relationship coupling to design a virtual model of the system-of-interest. The holonic perspectives allows us to consider this coupling relationship as descriptive of a WHOLE (H) and prescriptive of each parts as well in regards to system situation to perceive, as system-elements to architect. In this sense, we revisit this relation as an iterative, recursive and collaborative process of system co-specification to the quest of knowledge with each specialist engineering delivering constitutive models satisfying basic requirements. Our system co-modelling environment is itself composed of a set of system-components modelling environment, with the stated objective to preserve tools, methods and works of each stakeholders in order to facilitate the expression of their skills. The modelling at a system level is based on the system modelling language (SysML) to architecture the set of knowledge. Verification and validation are performed by co-execution of models around a co-simulation bus, including CISPI platform of SAFETECH project of CRAN constituting our case study

This study examines social factors in songwriting collaborations with the aim to understand the inner workings of co-writes. Previous research indicates significant benefits with songwriting collaborations, both related to productivity and creativity (e. g. Bennett 2012, Littleton &amp; Mercer, 2012). Nonetheless, it can be creatively frustrating to make music in a collaboration that does not work like expected. What is significant about the musical work in a fulfilling co-write? And how can you find your way out of struggle together? While there is qualitative research on musical collaborations, this study is distinguished by that the researcher is partaking in several co-writes. Six collaborations were documented with various methods, including video and audio recordings, post-hoc reflection, semi-structured interviews and communication memos. The comprised material was transcribed and analyzed in order to reveal socio-musical tendencies in the co-writes. The research suggests four socio-musical categories for explaining actions in co-writing sessions – ‘Artistic Concept’, ‘Concept’, ‘Meta’ and ‘External’. The two first categories are more artistically connoted, where the last two are more socially signified. During the study, purely artistic actions were outweighed by more socially connoted actions in the co-writes. This resulted in a fairly low generation of musical material per session. The prevalence of bonding may be seen as a way of avoiding rejection, which is a possible outcome when suggesting musical ideas (Bennett, 2012). The sessions that were most fulfilling for the researcher were characterized of nonverbal, musical means rather than linguistic ones - where the collaborators didn’t talk about the music, but connected through songwriting. High rates of fulfillment connected to musical communication was also supported by numerous co-writers in the project. / <p>Medley of songs created in the project. </p>

This dissertation contributes to our knowledge about the development of Maltese cooperatives, placing the process in a wider historical and ideological perspective. More importantly it delves into the learning that goes on in and around co-operatives. Finally it contributes to the discussion about the potential which co-operatives have in enabling communities to work towards a more equitable world. Three were the guiding questions. What do people learn in the co-op, as they get involved in setting up and running a community-owned enterprise? What do people learn from the co-op, as they interact with it in its day-to-day business? What do people learn for the co-op, as they turn towards co-operation to create a more equitable world? To answer these questions, I first conducted research about the origins of co-operation in Britain, the dissemination of the model across the British Empire, and its development in Malta. Then I conducted a case study research with two Maltese rural co-operatives, one at the village of Mġarr, the Mġarr Farmers’ Co-operative Society, and the other located at Manikata, Koperattiva Rurali Manikata. I interviewed ten co-operators from each case study, followed up by a group discussion with each co-op’s committee. I analysed the transcripts by making reference to authors who have contributed to the discussion around democracy, critical citizenship and critical pedagogy. The case studies show that in co-operatives people learn how to turn personal problems into collective struggles. They develop their personal and collective identities in their activism. They learn to assume responsibility in contributing towards the common good, becoming aware that taking action is a learning process at the individual and the collective level. The case studies also show that people learn from co-operatives in different ways. The co-operatives under study both organised non-formal educational activities open to the members of the community. They provided goods and services to the wider community, and customers learned as they interacted with both co-ops. Activists from both co-ops sought to build bridges with civil society and with political authorities in their search for alliances over to achieve their objectives. In doing so they could open up learning spaces beyond the confines of the co-op. Finally the research makes the case for co-operatives by showing how they have the potential to give voice to local communities. They can ‘claim spaces’ where individual abilities are turned into collective strength through participation in democratic dialogical processes. Cooperatives can scale up the struggle for legitimacy around local structures of feeling as they develop into oppositional or alternative discourses to the status quo.

The concept of co-optation offers vocabulary to discuss how concerns and demands of feminist movements are transformed on their way to, and within, mainstream organizations and policymaking. However, applications of this concept can have problematic implications, failing to grasp the complexity of social change efforts and contributing to divisions, rather than alliances, between different groups that work and fight for gender equality. This article argues that conceptual tools from organizational institutionalism can help to avoid these pitfalls by capturing the ambivalence of organizational change initiatives, and allowing us to identify not only counterintentional effects, but also subtle and unexpected opportunities of organizational gender equality work. I illustrate my arguments with empirical examples from research on gender equality work in Austrian universities.

En la presente tesis se han introducido y estudiado nuevas nociones de función co-radiante de valor real extendido y de valor conjunto, definidas en un cono de un espacio euclídeo. El estudio exhaustivo que se hace de ellas ha permitido hacer contribuciones en el análisis multivaluado no convexo, así como disponer de herramientas matemáticas adecuadas para analizar con un nivel de generalidad superior, las tradicionales funciones de producción que en la teoría económica se las denomina funciones de rendimientos decrecientes a escala. Se proponen las funciones alfa-co-radiantes que incluyen funciones como las de Cobb-Douglas de grado alfa y las de elasticidad de sustitución constante. Asimismo, se presentan representaciones convexas de las funciones alfa co-radiantes y se hacen algunos aportes para las funciones cóncavas y homogéneas de grado alfa. Los resultados de mayor relevancia en esta tesis se basan en las nociones originales de aplicación multivaluada coradiante, así como en la de aplicación multivaluada inversa co-radiante. Las aplicaciones multivaluadas co-radiantes de valor no convexo son importantes para el moderno tratamiento matemático de las tecnolog´ıas de producción. Se presenta un análisis minucioso de estas aplicaciones desde el punto de vista de la convexidad abstracta. Esto ´ultimo posee un conjunto de técnicas para problemas no convexos, usando ideas provenientes del análisis convexo. Los principales resultados son las representaciones externas para aplicaciones multivaluadas co-radiantes y para aplicaciones multivaluadas inversas co-radiantes, valiéndonos de aplicaciones multivaluadas denominadas elementales o generadoras. Asimismo, se define la función coste asociada a una aplicación multivaluada de producción y se hace un análisis de esta función en el esquema de la convexidad abstracta. Finalmente, se establecen condiciones que permiten recuperar una aplicación multivaluada primitiva a partir de la función coste. Cabe mencionar, que la convexidad abstracta tiene importantes aportes en áreas como la Optimización Global y la Teoríıa del Transporte ´ Optimo; por consiguiente la tesis se enmarca en un área de investigación de gran interés en la actualidad, que va más allá del esquema económico que motivó la presente investigación. / In this thesis have been introduced and studied new notions of co-radiant function of extended real and set value, defined in a cone of a Euclidean space. The comprehensive study that is made of them has allowed contributions in non-convex multivalued analysis, as well as the availability of proper mathematical tools to analyze with a level of greater generality, the traditional functions of production which in theory economic are known as diminishing returns to scale functions. Alpha-co-radiant functions that include alpha grade Cobb-Douglas and constant elasticity of substitution functions are presented. Also, convex representations of alpha co-radiant functions are presented and some contributions to the concave and homogeneous functions of alpha grade are made. The results of greater relevance in this thesis are based on the original notions of co-radiant multivalued map, as well as on inverse co-radiant multivalued map. The co-radiant multivalued maps of non convex value are important to the modern mathematical treatment of the production technologies. A thorough analysis of these maps is presented from the point of view of abstract convexity. This last has a set of techniques for not convex problems, using ideas from the convex analysis. The main results are the external representations for co-radiant multivalued maps and inverse co-radiant multivalued maps through multivalued maps called elemental or generating maps. Also, the cost function associated with a multivalued map of production is defined and an analysis of this function in the scheme of abstract convexity is made. Finally, conditions are established in order to recover a primitive multivalued map from the cost function. It is worth mentioning, that the abstract convexity has significant contributions in areas such as Global Optimization and the Theory of the Optimal Transportation; therefore the thesis is part of an area of research of great interest today, which goes far beyond the economic scheme that gave rise to the present investigation. / Tesis