Second-harmonic generation of ZnO nanoparticles synthesized by laser ablation of solids in liquids

We report the synthesis of small zinc oxide nanoparticles (ZnO NPs) based colloidal suspensions and the study of second-harmonic generation from aggregated ZnO NPs deposited on glass substrates. The colloidal suspensions were obtained using the laser ablation of solids in liquids technique, ablating a Zn solid target immersed in acetone as the liquid medium, with ns-laser pulses (1064 nm) of a Nd-YAG laser. The per pulse laser fluence, the laser repetition rate frequency and the ablation time were kept constant. The absorption evolution of the obtained suspensions was optically characterized through absorption spectroscopy until stabilization. Raman spectroscopy, SEM and HRTEM were used to provide evidence of the ZnO NPs structure. HRTEM results showed that 5–8 nm spheroids ZnO NPs were obtained. Strong second-harmonic signal is obtained from random ZnO monocrystalline NPs and from aggregated ZnO NPs, suggesting that the high efficiency of the nonlinear process may not depend on the NPs size or aggregation state

Influence of oxygen pressure on the fs laserinduced oxidation of molybdenum thin films

We present a study of femtosecond (1028 nm, 230 fs, 54.7 MHz) laser processing on molybdenum (Mo) thin films. Irradiations were done under ambient air as well as pure oxygen (O2) at various gauge pressures (4, 8, 12 and 16 psi). Our results indicate that the high heating rates associated with laser processing allow the production of different molybdenum oxides. Raman spectroscopy and scanning electron microscopy are used to characterize the molybdenum oxidation for the different irradiation and oxygen pressures parameters chosen showing a high correlation between well-defined oxidation zones and the oxygen pressure surrounding the samples during the irradiation of the Mo thin films

Qualitative Supervision of Naval Diesel Engine Turbocharger Systems

FAC Intelligent Components and Instruments for Control Applications, Malaga, Spain, 1992This paper presents a qualitative model the diesel engine turbocharger system of a ship. The paper also shows how qualitative models can be use for an intelligent monitoring of the process concerned

La liberación de la Madre Tierra: Más que la toma de un territorio

Objective: this article reconfigures the dynamics of the process of the Liberation of Mother Earth by the Nasa people, making it visible in a commitment to re-territorialization that begins with the recovery of dispossessed lands. Methodology: this historical-hermeneutic research approach, involved participant observation, the use of techniques such as video and audio recording, the application of informal interviews with representatives of the Nasa community, and the documentary analysis of primary and secondary sources prepared by the community. Results: the research describes the main land disputes in the region, from colonization to internal armed conflict. It presents the history of organization that the community has put into practice there, with special emphasis on the process of the Liberation of Mother Earth; based on the accumulation of organizational experiences, responding to the de-territorialization processes led by external agents against the indigenous people of Norte del Cauca has become possible. Finally, the scenarios and gambles that have resulted from this process, and their relationship with other social movements are analyzed. Conclusions: the reflections and experiences around the process of Liberation of Mother Earth raise hopeful horizons for the construction of autonomous ways of life. They are focused on a different relationship with the earth which allows inquiry and confrontation of the prevailing system.Objetivo: este artículo reconfigura las dinámicas del proceso de la Liberación de la Madre Tierra del pueblo Nasa, para visibilizarlo en una apuesta por la reterritorialización que inicia con la recuperación de tierras despojadas. Metodología: este trabajo investigativo de enfoque histórico–hermenéutico, implicó la observación participante, el uso de técnicas como registro de video gráfico y de audio, la aplicación de entrevistas informales con representantes de la comunidad Nasa, y el análisis documental de fuentes primarias y secundarias elaborados por la comunidad. Resultados: se describen las principales disputas en torno a la tierra en la región, pasando desde la colonización hasta el conflicto armado interno. Presenta la historia de organización que allí ha puesto en práctica la comunidad, haciendo especial énfasis en el proceso de Liberación de la Madre Tierra; pues a partir de este cúmulo de experiencias organizativas ha sido posible responder a los procesos de desterritorialización que han propiciado agentes externos a los pueblos indígenas del norte del Cauca. Finalmente, se analizan los escenarios y apuestas que han resultado de este proceso, y su relación con otros movimientos sociales. Conclusiones: las reflexiones y experiencias en torno al proceso de Liberación de la Madre Tierra plantean horizontes esperanzadores para la construcción de modos de vida autónomos, centrados en un relacionamiento distinto con la tierra, que permiten cuestionar y confrontar el sistema imperante

La mirada del fotógrafo en la construcción del imaginario doméstico: Casa Nesbitt - Richard Neutra | Julius Shulman / Casa Obregón - Obregón & Valenzuela | Paul Beer

Màster universitari en Estudis Avançats en Arquitectura: Projecte. Procés i ProgramacióLa fotografía podría ser para la arquitectura una de las herramientas más utilizadas en la divulgación de sus ideas y en muchos casos el único mecanismo que permite la visita al proyecto. El fotógrafo acentúa en la imagen los valores que a veces el espectador no consigue ver a simple vista. La aparente semejanza o familiaridad de dos imágenes de dos proyectos localizados en lugares geográficamente distantes entre sí, aunque a primera vista formalmente cercanos, son el punto de partida de esta investigación, que se desarrolla bajo una metodología comparativa con el objeto de efectuar el estudio de las obras a través de la mirada de los fotógrafos; mas no indagar sobre la influencia que tuvo una sobre la otra. El análisis busca comprender si el modo de vida que se transmite a través de las fotografías coincide con la manera en cómo se vive cada casa. Pues a través de 64 registros encontrados de ambas obras se permite viajar hacia ellas a repasando la mirada de los fotógrafos Julius Shulman y Paul Beer

How do Spanish disability support officescontribute to inclusive education in the university?

This article analyzes the functioning of disability support offices and their contribution to inclusive education in seven Spanish universities from the perspective of staff. Using a qualitative methodology, interviews with office staff were conducted, and data were analyzed through an inductive coding system. The results are organized around five themes: characteristics of disability support offices, staff training, functions performed by different services, barriers and opportunities identified by office staff, and proposals to improve attention given to disabled students. Information gathered leads to the conclusion that the work carried out in disability support offices must receive support from universities, as these offices are a key element for the access and retention of students with disabilities in the university and for the successful completion of their studies

Formation of b-Bi2O3 and d-Bi2O3 during laser irradiation of Bi films studied in-situ by spatially resolved Raman spectroscopy

The formation of different phases of Bi2O3 induced by laser irradiation of Bi films has been assessed in situ by micro-Raman spectroscopy as a function of laser wavelength, power density and irradiation time. Raman mapping of the irradiated samples enabled a spatially-resolved study of the distribution of the formed Bi2O3 phases. Red laser (633 nm) irradiation was found to induce the appearance of b-Bi2O3, within a certain range of power densities, by diffusion-controlled processes. In contrast, ultraviolet (UV, 325 nm) laser irradiation, above a certain power density threshold, initially induces the formation of both b and d-Bi2O3 phases. The amount of the produced d-Bi2O3 phase increases by increasing the irradiation time, while that of the b phase follows the opposite trend. UV laser irradiation seems to be a suitable method to produce room temperature stable d-Bi2O3 patterns on Bi film

Una visión de los materiales en la escala "nano"

2 páginas.Breve biografía de Asunción Fernández, investigadora del Instituto de Ciencias Materiales de Sevilla (ICMS-CSIC).Peer reviewe

Preparation and Characterization of New Liposomes. Bactericidal Activity of Cefepime Encapsulated into Cationic Liposomes

Cefepime is an antibiotic with a broad spectrum of antimicrobial activity. However, this antibiotic has several side effects and a high degradation rate. For this reason, the preparation and characterization of new liposomes that are able to encapsulate this antibiotic seem to be an important research line in the pharmaceutical industry. Anionic and cationic liposomes were prepared and characterized. All cationic structures contained the same cationic surfactant, N,N,N-triethyl-N-(12-naphthoxydodecyl)ammonium. Results showed a better encapsulation-efficiency percentage (EE%) of cefepime in liposomes with phosphatidylcholine and cholesterol than with 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE). The presence of cholesterol and the quantity of egg-yolk phospholipid in the liposome increased the encapsulation percentage. The bactericidal activity against Escherichia coli of cefepime loaded into liposomes with phosphatidylcholine was measured. The inhibitory zone in an agar plate for free cefepime was similar to that obtained for loaded cefepime. The growth-rate constant of E. coli culture was also measured in working conditions. The liposome without any antibiotic exerted no influence in such a rate constant. All obtained results suggest that PC:CH:12NBr liposomes are biocompatible nanocarriers of cefepime that can be used in bacterial infections against Escherichia coli with high inhibitory activity