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The case presents a qualitative situation that has been developed following the methodology of the classics of economics, i.e., philosophical, from which logic, which laid the foundations of the knowledge of economics, derives. The case analyzes a warehouse company’s general situation that operates with apparent effectiveness in the Peruvian market. First, it relates the author’s personal experience who, together with his partner, proposes the generational change in the company between his son and himself, with expectations of an improvement in the management of the company in the face of the imminent and rapid technological innovation. Likewise, the company's problems are exposed because of the death of one of the partners, the constant innovation in the market, and the changes in the chain of command. Faced with this situation, the discussion may focus on the approach to future decisions in the company.El caso presenta una situación cualitativa que se ha desarrollado siguiendo la metodología de los clásicos de la economía, es decir, filosófica, de la que deriva la lógica que sentó las bases del conocimiento de la economía. El caso analiza la situación general de una empresa almacenista que opera con aparente efectividad en el mercado peruano. En primer lugar, se relata la experiencia personal del autor quien, junto a su socio, propone el relevo generacional en la empresa entre su hijo y él mismo, con expectativas de una mejora en la gestión de la empresa ante la inminente y rápida innovación tecnológica. Asimismo, se exponen los problemas de la empresa por el fallecimiento de uno de los socios, la constante innovación en el mercado y los cambios en la cadena de mando. Ante esta situación, la discusión puede centrarse en el planteamiento de decisiones futuras en la empresa

Modellbasierter Entwurf lastflexibler Festbettreaktoren

Model-based methodologies for the design of chemical reactors gain increasing importance in the field of chemical reaction engineering. On the basis of a suitable mathematical model of the chemical reactor, a numerical optimization problem is solved and decision variables of the reactor such as reactor dimensions and operating conditions are determined that maximize a desired objective function while constraints are fulfilled. Initiated by a changing availability of raw materials and the transition to more renewable energy, an important aim of high current relevance are more tolerant and flexible chemical reactors. If a reactor is tolerant with respect to changes of the flow rate, it is referred to as a load flexible reactor. Such reactors are not operated at a constant steady state operating point but highly dynamically within a given load range. The design of load flexible reactors is a challenging task especially for highly exothermic reactions in wall-cooled fixed bed reactors. Fluctuations of the flow rate provoke changes of the axial temperature profile in the reactor which can damage the reactor and catalyst. Moreover, the changing residence time and temperature profile cause variations of the product composition. These challenges can be managed by a more conservative reactor design, but it creates a performance gap between conventional and load flexible reactors. For this reason, there is a strong need for the intensification of load flexible fixed bed reactors in order to reduce this performance gap. In the present thesis, novel numerical optimization strategies are presented that enable the model-based design of load flexible fixed bed reactors. The proposed optimization framework is demonstrated using the methanation of carbon dioxide as an example process. In the context of Power-to-Gas processes for energy storage, the methanation is a suitable case study of high current relevance for both research and society. One approach is based on an optimization of the reactor design while considering multiple steady state operating points within the desired load range simultaneously. The reactor dynamics are not explicitly considered in the problem formulation. Therefore, the feasibility of the reactor design to dynamic changes of the flow is verified in a second step by means of a simulation of an appropriate dynamic scenario. While this approach requires a comparatively low computational effort, there exist cases where the approach fails to yield a reactor design that is feasible for the dynamic transition periods. For these cases, a second optimization approach is proposed. The special concept is to consider the reactor dynamics already within the optimization problem formulation. The reactor is optimized not for some steady state operating points but for a worst case dynamic scenario. In this regard, a steady state and a dynamic reactor model are coupled and solved simultaneously. This approach is computationally more expensive but guarantees feasibility for the dynamic transition periods. The two proposed optimization strategies overcome major limitations of existing numerical works in that field. So far, no method was proposed in open literature that considers load flexibility and feasibility of the dynamic transition periods within one design procedure. Based on the presented optimization strategies, several methods to intensify the load flexible reactor design are determined. This includes an optimized control strategy, where the coolant temperature is dynamically changed in accordance to the current load level. A straightforward and effective intensification method is a staged reactor concept with a catalyst dilution profile. The heat management is considerably improved for the load flexible operation. An interesting potential is revealed for the intensification of the reactor by a distributed dosing strategy of the feed to different reactor stages. In this case, the axial velocity field can be adapted in accordance to the current load level. The outlined contributions to the model-based design of load flexible reactors are complemented by a comprehensive study on the dynamic behavior of fixed bed reactors and the suitable selection of reactor models. In this regard, a novel approach for the comparison of reactor models with different levels of complexity is presented. On the basis of this approach, the importance of the dimensionality and the phase treatment of a reactor model for the description of the steady state and dynamic behavior is systematically clarified. A key finding is that the predicted times of the dynamic transition periods considerably differ between heterogeneous and pseudohomogeneous reactor models. However, if the transport resistances are low, pseudohomogeneous models are also able to describe the dynamic transition periods well. The presented optimization strategies and findings of this thesis are well transferable to further applications and are able to unlock the potential of load flexible reactors.Modellbasierte Methoden für den Entwurf chemischer Reaktoren erlangen eine zunehmende Bedeutung in der chemischen Reaktionstechnik. Ziel ist es, die Freiheitsgrade eines Reaktors wie Abmessungen und Betriebsbedingungen so festzulegen, dass die Reaktorleistung maximal wird und Nebenbedienungen erfüllt werden. Dazu wird auf Grundlage eines geeigneten mathematischen Reaktormodells ein numerisches Optimierungsproblem gelöst. Aufgrund der veränderlichen Verfügbarkeit von Rohstoffen und der Energiewende ist der Entwurf toleranter und flexibler Reaktoren ein Ziel mit besonders hoher aktueller Relevanz. Ein Reaktor, der flexibel gegenüber Schwankungen des Volumenstroms ist, wird als lastflexibler Reaktor bezeichnet. Solch ein Reaktor wird nicht konstant an einem stationären Betriebspunkt betrieben, sondern hoch dynamisch in einem definierten Lastbereich. Der Entwurf von lastflexiblen Reaktoren ist eine große Herausforderung, insbesondere für stark exotherme Reaktionen in wandgekühlten Festbettreaktoren. Schwankungen des Volumenstroms verursachen Veränderungen des axialen Temperaturprofils im Reaktor, was zu einer Schädigung des Reaktors und Katalysators führen kann. Darüber hinaus ändert sich die Produktzusammensetzung aufgrund der schwankenden Verweilzeit und Temperatur. Diese Herausforderungen können durch ein konservativeres Reaktordesign beherrscht werden. Die Konsequenz ist jedoch eine reduzierte Leistung lastflexibler Reaktoren im Vergleich zu konventionellen Reaktoren. Aus diesem Grund ist es ein wichtiges Ziel, durch die Intensivierung lastflexibler Festbettreaktoren diesen Leitungsverlust zu minimieren. In der vorliegenden Arbeit werden neue numerische Optimierungsansätze zum Entwurf lastflexibler Reaktoren vorgestellt. Das vorgeschlagene Optimierungskonzept wird dabei exemplarisch anhand der Methanisierung von Kohlenstoffdioxid erarbeitet. Die Methanisierung ist im Kontext von Power-to-Gas Prozessen zur Energiespeicherung eine geeignete Fallstudie von hoher aktueller Relevanz für die Wissenschaft wie für die Gesellschaft. Ein Ansatz basiert auf der Optimierung des Reaktordesigns unter simultaner Berücksichtigung von mehreren stationären Betriebspunkten innerhalb des geforderten Lastbereichs. Das dynamische Reaktorverhalten wird dabei nicht explizit in der Problemformulierung berücksichtigt. Daher wird in einem zweiten Schritt die Gültigkeit des Reaktordesigns bezüglich dynamischer Lastveränderungen mittels einer Simulation eines geeigneten dynamischen Lastszenarios verifiziert. Während dieser Ansatz einen verhältnismäßig geringen Rechenaufwand benötigt, kann jedoch für manche Fälle die Gültigkeit für die dynamischen Übergangszustände nicht gewährleistet werden. Für diese Fälle wird ein zweiter Optimierungsansatz vorgeschlagen. Die Idee ist, die dynamische Laständerung bereits in die Problemformulierung zu integrieren. Der Reaktor wird dabei nicht für verschiedene stationäre Betriebspunkte optimiert, sondern für ein worst case dynamisches Szenario. Dazu werden ein stationäres und ein dynamisches Reaktormodell gekoppelt und gleichzeitig gelöst. Dieser Ansatz benötigt einen deutlich höheren Rechenaufwand, garantiert jedoch Gültigkeit für die dynamischen Laständerungen. Die zwei Optimierungsstrategien überwinden die Limitationen existierender numerischer Arbeiten in diesem Fachgebiet. Bis jetzt wurde noch keine Methode in der offen zugänglichen Literatur vorgestellt, bei der Lastflexibilität sowie die dynamischen Übergangszustände in einer Prozedur berücksichtigt werden. Unter Verwendung der vorgestellten Optimierungsstrategien werden mehrere Konzepte zur Intensivierung lastflexibler Reaktoren bestimmt. Eine Möglichkeit ist eine optimierte Kontrollstrategie, bei der die Kühlmitteltemperatur dynamisch an das aktuelle Lastniveau angepasst wird. Eine eher unkomplizierte aber effektive Intensivierungsmethode ist Aufteilung des Reaktors in mehrere Zonen und eine Verdünnung des Katalysatorbetts mit inerten Partikeln. Dadurch wird ein besseres Wärmemanagement für den lastflexiblen Betrieb erreicht. Auch die Intensivierung des Reaktors durch eine Verteilung des Volumenstroms auf unterschiedliche Zonen zeigt ein interessantes Optimierungspotential. Der Vorteil ist, dass das axiale Geschwindigkeitsfeld dem aktuellen Lastniveau angepasst werden kann. Die vorgestellten Beiträge zum modellbasierten Entwurf lastflexibler Reaktoren werden durch eine umfassende Studie des dynamischen Reaktorverhaltens und der geeigneten Modellauswahl stationärer und dynamischer Reaktormodelle vervollständigt. Hierfür wird ein neuer Ansatz für den Vergleich von Reaktormodellen unterschiedlicher Komplexität vorgestellt. Unter Verwendung der Methode wird die Relevanz der Dimensionalität und der Phasenbeschreibung unterschiedlicher Modelle zur Beschreibung des stationären und dynamischen Verhaltens systematisch geklärt. Eine zentrale Erkenntnis ist, dass sich die berechneten Zeiten der dynamischen Übergangszustände zwischen heterogenen und pseudohomogenen Reaktormodellen deutlich unterscheiden. Falls die Transportwiderstände jedoch gering sind, können auch pseudohomogene Modelle das dynamische Verhalten gut beschreiben. Die vorgestellten Optimierungsstrategien und Erkenntnisse sind über diese Arbeit hinaus für andere Anwendungen übertragbar und ermöglichen das Potential lastflexibler Reaktoren zu entfalten

A New LCA Methodology of Technology Evolution (TE-LCA) and its Application to the Production of Ammonia (1950-2000) (8 pp)

Goal, Scope and Background: This paper presents a new LCA method of technology evolution (TE-LCA), and its application to the production of ammonia, the second largest chemical product in the world, over the last fifty years. The TE-LCA of a chemical process is the procedure in which historical information on a process, mainly the evolution of technical parameters, is translated by simulation to mass and energy balances as a function of time. These mass and energy balances are then transformed into environmental impact indicators using common LCA approaches. Finally, the evolution of environmental impact resulting from the investigated process can be related to its technical and other, i.e. legislative, developments. Methods: The technological evolution of the production of ammonia was compiled according to three basic sources of information: patents, publications and industry data. From these sources in a first step, the major technological advances of the process were identified as a function of time delivering different process variants that were modelled using the simulation software Aspen Plus®. In a second step, the evolution of environmental regulations is studied. For those energy related emissions that were regulated, e.g. SOx and NOx, it was assumed that threshold values defined in legislation were realized immediately. The aggregation of both steps allows the calculation of the emissions resulting from the production (cradle to gate view) of the investigated chemical as a function of time. Results and Discussion: The application of the TE-LCA to the production of ammonia revealed when and to which extent technological and legislative developments resulted in the reduction of energy related emissions in the production of this chemical compound. Overall, the reduction of emissions from ammonia production was highly influenced by the technological development and only to a lower extent by environmental regulations. Conclusion: The results obtained from the TE-LCA method is useful to reveal how the environmental performance of a process developed in the past and to identify the reasons for this development. The investigated case study of ammonia production shows that investment in technological development also paid off in terms of being ahead of tightened environmental legislation that might bear potential cost consequences such as carbon dioxide tax. Outlook: The presented method can be easily extended by including an economic analysis, which provides additional information on why certain technological developments were enforced and which the economic consequences of changes in environmental legislation were. The new methodology has to be applied to additional case studies, i.e. to other chemical sectors than basic chemicals and to other branches than chemicals. In other chemical sectors, toxic emissions from the production process might have to be considered and trade-offs between these and the overall energy consumption might resul

Indicadores de atenção básica em saúde bucal: associação com as condições socioeconômicas, fluoretação de águas e a estratégia de saúde da família no Sul do Brasil

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências da Saúde. Programa de Pós-Graduação em Saúde Pública.Analisou-se os indicadores de saúde bucal do pacto de atenção básica do SUS (cobertura, razão de exodontias em relação aos procedimentos individuais e cobertura de procedimentos coletivos na população de até 14 anos de idade) em municípios do Sul do Brasil (n=1159) entre 2000 a 2005. Adicionalmente testaram-se associações dos indicadores com variáveis socioeconômicas, de provisão de serviços odontológicos, fluoretação de águas e cobertura da saúde bucal na estratégia de saúde da família. Foram associados positivamente com o aumento da cobertura, o estado (RS com a menor), população rural, IDH, número de dentistas pela população e cobertura da saúde bucal no PSF. Para razão de exodontias foram associados o estado (SC e RS maiores), negativamente com população rural, IDH, número de dentistas pela população e cobertura da saúde bucal no PSF e positivamente o índice de Gini. Procedimentos coletivos foram associados negativamente com índice de Gini, intensidade de indigência e razão do número de dentistas pela população e positivamente com estado (menor no RS), população rural IDH e cobertura da saúde bucal no PSF. This paper analyzed the primary dental care indicators of the Brazilian National Health System (SUS) as following coverage of dental attendance, ratio between dental extraction and dental procedures and coverage of preventive measures among children up to 14 years-old in the municipalities from the southern region of Brazil (n=1159) between years 2000 and 2005. In addition, the association of these indicators with socioeconomic indicators, dental services, water fluoridation and coverage of the oral health care in the Family Health Program (FHP) was tested. The increase of the coverage of dental attendance was positively associated with percentage of rural population, Human Development Index (HDI), number of dentists per capita and FHP coverage. Dental extraction was negatively associated with percentage of rural population, HDI, number of dentists per capita and the FHP coverage, and positively associated with Gini index. Preventive dental measures were negatively associated with Gini index, poverty and number of dentists per capita, and positively associated with the percentage of rural population, HDI and FHP coverage

Reversible tetraplegia caused by a transoral penetrating stick injury

A 3-year-old, male German shepherd dog was referred because of acute tetraplegia following endoscopic removal of stick fragments from the oral cavity. Magnetic resonance imaging revealed an extradural T2W- and T1W-hypointense linear structure within the vertebral canal at the level from the C1 to mid-C2 cervical vertebral body, causing pronounced dorsolateral spinal cord compression and spinal cord oedema extending to the caudal end of the C2 vertebra. A dorsal laminectomy was performed at the level of the C1-C2 vertebra. Three wooden fragments with lengths of up to 4 cm, which were located adjacent to the spinal cord, were removed from the vertebral canal. The dog was still tetraplegic after surgery. Postoperative care consisted of analgesics, antibiotics, bladder management, intensive neurorehabilitation and physical therapy. Recovery of ambulation was regained 3 weeks after surgery

Pequeña empresa: papel de nuevo gerente de marketing Escobita Nueva

It presents the case of a family-owned garment company whose development has responded more to the founder's desire to provide his family with a sufficiently comfortable living than to the entrepreneurial vision that would have allowed it to respond to market signals, which has led the company to lose ground to the competition. The organization of production is described; the market strategy: product, price, distribution and sales, promotion and advertising; the characteristics of the market and the competition; and the financial situation. When the founder's son takes over the business, he evaluates this situation and considers different alternatives for action: specializing in a new product line; maintaining the same product line, but with new designs; entering other markets; changing its pricing policy; its distribution and sales system, as well as promotion and advertising. The discussion of the case can be oriented towards the analysis of these options.Se presenta el caso de una empresa familiar de confección cuyo desarrollo ha respondido más al deseo del fundador de proporcionar a su familia una vida suficientemente cómoda que a la visión empresarial que le habría permitido responder a las señales del mercado, que ha llevado a la empresa perder terreno frente a la competencia. Se describe la organización de la producción; la estrategia de mercado: producto, precio, distribución y ventas, promoción y publicidad; las características del mercado y la competencia; y la situación financiera. Cuando el hijo del fundador se hace cargo del negocio, evalúa esta situación y considera diferentes alternativas de acción: especializarse en una nueva línea de productos; manteniendo la misma línea de productos, pero con nuevos diseños; entrar en otros mercados; cambiar su política de precios; su sistema de distribución y ventas, así como de promoción y publicidad. La discusión del caso puede orientarse hacia el análisis de estas opciones

How genome editing changed the world of large animal research

The first genetically modified large animals were developed in 1985 by microinjection to increase the growth of agricultural livestock such as pigs. Since then, it has been a difficult trail due to the lack of genetic tools. Although methods and technologies were developed quickly for the main experimental mammal, the mouse, e.g., efficient pronuclear microinjection, gene targeting in embryonic stem cells, and omics data, most of it was—and in part still is—lacking when it comes to livestock. Over the next few decades, progress in genetic engineering of large animals was driven less by research for agriculture but more for biomedical applications, such as the production of pharmaceutical proteins in the milk of sheep, goats, or cows, xeno-organ transplantation, and modeling human diseases. Available technologies determined if a desired animal model could be realized, and efficiencies were generally low. Presented here is a short review of how genome editing tools, specifically CRISPR/Cas, have impacted the large animal field in recent years. Although there will be a focus on genome engineering of pigs for biomedical applications, the general principles and experimental approaches also apply to other livestock species or applications

Experimental investigation of the pre–Darcy regime

The validity of Darcy’s law at very low Reynolds numbers is discussed controversially in literature, as some authors propose a pre–Darcy flow regime below some critical Reynolds number. The scope of this work is to investigate this problem experimentally. Therefore, a packing of glass spheres is perfused by different glycerin–water solutions. A linear behaviour between the flow velocity and the pressure drop through the packed spheres is found in the complete investigated range of Reynolds number Red′, based on the mean-pore diameter d′ and mean-pore velocity v′ with 10−9≤Red′≤10−1. This contradicts the results of different authors like Fand et al. (1987) or Kececioglu and Jiang (1994), postulating a pre–Darcy regime for Red′≤2.8⋅10−6 or Red′≤0.13, respectively