Interfacial Properties of Colloidal Silica Dispersions in Contact with Solutions of Fatty Amines in Hexane

Many natural phenomena and technologies are concerned with the interactions between micro- or nano-metre sized particles and surfactant molecules at liquid interfaces. Highly stable emulsions are produced by using surfactants to modify the surfaces of nanoparticles. Particle attachment to bubbles is controlled by surfactant adsorption in flotation technologies. So far, however, few experimental studies have explored the properties of these complex interfacial layers

Effect of Silica Nanoparticles on Rheological and Structural Properties of DPPC Langmuir Monolayers

The study of the interaction between nanoparticles and model of lung surfactant is of great relevance to understand possible adverse effects of inhalable nanoparticles on the respiratory function [1,2]. We report therefore a study on the interfacial properties, structure and dilational rheology of monolayers of the major lipidic component of the lung surfactant, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), in the presence of silica nanoparticles. Investigations are performed by a Langmuir trough equipped with Brewster Angle Microscopy

Refuelling tanker aerodynamics and hose characteristics

The present work is conducted within the context of air to air refuelling technologies and aims at the development of an understanding of a typical refuelling tanker wake like that of an A330 [54] and the A400M [54]. The wake is particularly investigated within the near field and extended near field wake regions in close vicinity to the rear fuselage. Moreover, the interaction between the wake and the refuelling hose is studied including the resulting hose characteristics. A number of refuelling conditions and aircraft models are considered for the investigation of the wake. Moreover, an arbitrary hose fairing model is considered to study the effect of the fairing on the flow field and the refuelling hose. Different refuelling configurations are taken into account for the investigation of the hose characteristics. Various hose exit positions were studied within the near field wake to assess the impact on the hose characteristics. The probe hose engagement with the associated hose whip phenomenon is a major topic within this work. The hose whip is a highly undesired phenomenon and is amplified by a specific hose shape which is characterised through an inflection point along the hose. The present research reveals that the rear fuselage wake has a crucial impact on the hose characteristics. In particular, the rear fuselage upwash is the primary cause for formation of the undesired hose inflection point. The findings obtained from the present research are used for the suggestion of palliatives to avoid undesirable hose characteristics. In particular, there is one approach recommended which aims at the avoidance of a hose-upwash interaction. It leads to the suggestion of a circumferentially shifted and radially displaced hose exit and deployment of the refuelling hose

Short Time Dynamic Interfacial Tension as Measured with Capillary Pressure Technique

Dynamic interfacial tension measurements in the short time range are a major request for controlling interfacial processes in modern, highly dynamic technologies. Capillary pressure measurements for growing and oscillating drops represent a good way to fulfil these requirements. The corresponding quantitative data analysis, however, requires the solution of rather complex theories on the hydrodynamics of growing drops and the adsorption dynamics at the drop surface and possible mass transfer across interfaces for liquid/liquid systems

Man at the centre of technology. A philosophical investigation of anthropological knowledge in man-machine-interfaces

The paper aims to examine the construction, circulation, and transformation of knowledge about man (anthropological knowledge) in human-technology interaction in the 20th century. The analysis focuses on the prerequisites of the industrial working world and its implicit knowledge about human beings. However, the basis and starting point of technical adaptation is usually ignored: The concepts of “man” and the anthropological knowledge gained experimentally from a anthropocentric designed interface. Based on the concept of an intuitive interface design this problem will be investigated. The questions posed by this article as well as the objectives associated with them open up an interdisciplinary framework between philosophy of technology, philosophical anthropology and history of science given that they not only focus – by means of historical reconstruction – on historical changes in technological developments. They also address the issue of generation and transformation of anthropological knowledge in the definitions and interactions of “man” and “technology”

Simon, Zoltán Boldizsár/Deile, Lars (Hrsg.): Historical Understanding. Past, Present, and Future, 320 S., Bloomsbury Academic, London 2022.

Der Begriff „Verstehen“ ist vielsinnig und besitzt mehrere Bedeutungsebenen, da er ganz schematisch – nimmt man Martin Heideggers Fundamentalontologie mal heraus, die Verstehen als ein Existenzial begreift – auf der einen Seite einen Grundbegriff unserer sozialen und kulturellen Lebenswelt darstellt, um unsere Mitmenschen und deren Handlungen (auch im Rückblick) zu verstehen. Auf der anderen Seite müssen wir aber auch Sinn verstehen: den Sinn von Texten, von Informationen, von Zeichen, von Regeln, von Traditionen, Gesetzen, Formularen und so weiter. Damit ist Verstehen ein Grundbegriff der Hermeneutik, also der (Kunst‑)Lehre des Verstehens oder der Interpretation von Texten. Auf dieser Grundlage wurde der Begriff zu einem wissenschaftstheoretischen und -philosophischen Konzept, an dem man seit Johann Gustav Droysen und Wilhelm Dilthey die Abgrenzung der Geistes- von den Naturwissenschaften festgemacht hat (S. 3 f.). Verstehen ist – wie Dilthey formuliert hat – die Methode, die die Geisteswissenschaften erfüllt. Es „ist das grundlegende Verfahren für alle weiteren Operationen der Geisteswissenschaften“ beziehungsweise „Verstehen [ist] grundlegend für die Geisteswissenschaften“. Und andererseits ist Verstehen der Fundamentalbegriff der von ihm postulierten deskriptiven Psychologie. Hier lautet das einschlägige Dilthey-Zitat: „Die Natur erklären wir, das Seelenleben verstehen wir.“ Die Frage nach dem Verstehen zeigt sich somit immer auch als die Frage nach dem Subjekt und Objekt des Verstehens, seien es Menschen, Handlungen oder Texte. Wer versteht wen oder was? Reicht es, wenn man „Verstehen“ als rationales Erfassen, Begreifen und Erkennen tieferer Einsichten und komplexerer Zusammenhänge definiert, oder impliziert es mehr

Effect of laundry detergent formulation on the performance of alkaline phytoproteases

Background: Proteases constitute the largest product segment in the global industrial enzymes market; they are used in food, pharmaceutical, leather, textile, wood and detergent industries. Alkaline proteases improve the cleaning efficiency of detergents and represent one of the most successful applications of modern industrial biotechnology. The aim of this work was to study the performance of two alkaline phytoproteases, araujiain (Araujia hortorum Fourn.) and asclepain (Asclepias curassavica L.), for their potential application as additive in laundry detergent formulations. Results: The effect of pure non-ionic and ionic surfactants on proteolytic activity of araujiain and asclepain was analyzed measuring the remaining activity after 1 hr of incubation of those enzymes in aqueous solutions of surfactants at different concentrations (0.1, 0.4 and 1% v/v) and temperatures (25, 40 and 60oC). Besides, the compatibility of the enzymes with six commercial laundry detergents was also studied measuring the remaining proteolytic activity at 37oC after 1 hr. Commercial detergent components influenced in different ways on araujiain and asclepain, in spite of the similar behaviour of the two enzymes in buffer. In commercial detergent solutions, araujiain expressed between 60% and 140% of its remaining proteolytic activity in buffer (pH 8.5) at 37oC after 1 hr, while asclepain, was practically inactivate in most of them at the same conditions. Conclusions: Proteolytic extract of Araujia hortorum fulfilled all the requirements for its application as additive for laundry detergents: high stability in a broad temperature range (25-70oC), high activity in alkaline pH (7.5-9.5) and very good compatibility with the commercial detergent additives. Nevertheless, in spite of its high stability and activity in buffer, the proteolytic extract of Asclepias curassavica did not show the same performance than araujiain.Centro de Investigación de Proteínas Vegetale

Planificación de la implementación de estrategias de enseñanza innovadoras de los contenidos curriculares de la asignatura Biología del Ciclo Básico de la Facultad de Ciencias Exactas

El presente trabajo pretende elaborar un diseño para implementar estrategias innovadoras en la enseñanza de los contenidos curriculares de Biología, con el objeto de minimizar el impacto que genera en los estudiantes atravesar los primeros años de la universidad. La Asignatura se dicta en el 2° año dentro del Ciclo Básico común a todas las Carreras de la Facultad de Ciencias Exactas de la UNLP. Los alumnos que ya han transitado su primer año universitario, al siguiente año, demuestran que no han adquirido aún el oficio de un estudiante universitario; por ello la autora asume que poseen características compatibles con alumnos “noveles” y/o “ingresantes”. Estrategias trabajadas exitosamente en un Proyecto de Extensión dirigido a estudiantes secundarios, se implementaron en la cátedra pero no cumplieron con las expectativas. Por lo expuesto, se buscaron nuevas estrategias y surgió un listado que contenía las más promisorias, las cuales fueron implementadas en simultáneo con las anteriores durante las clases taller de Biología. Mediante el análisis comparativo de estas herramientas ensayadas en ambos ámbitos (proyecto de extensión y curso universitario), se escogieron las más valoradas por los estudiantes y por los docentes implicados en esta tarea. Dicha selección se complementará con otras estrategias y, el conjunto de ellas, será el que se propone implementar en este proyecto en una comisión de innovación. Se espera incrementar las competencias requeridas para el buen desempeño no sólo en Biología sino en la carrera y, de ese modo, contribuir a mejorar las posibilidades de permanencia de los estudiantes.Facultad de Ciencias Exacta