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To computer-simulate solar-concentrating facilities, an accurate knowledge of the Sun’s position as a function of latitude, longitude, time and date is required. In this work, it is reported first a simplified description of a general algorithm, developed by the astronomy community to accomplish that. Our implementation of this algorithm (included in our Light Analysis Modelling package) has been successfully validated against well trusted astronomy data. The software was then used to produce a wide range of results for 2024, for two well-known research facilities, the most northern (Jülich, Germany) and the most southern (Protaras, Cyprus) heliostat fields listed in the official SFERA-III EU project. This includes altitude and azimuth data, sunrise and sunset data, analemma curves, angular speed data and geocentric Sun trajectories around the observer’s position. Other ray-tracing techniques are also reported to help simulate the Sun vectors reaching the solar devices. The truly inspiring results obtained show how important this type of software is, from the scientific and industrial point of view, to better understand our relationship with our neighbor star, the Sun.

This work demonstrates that the quasi-homogeneous distribution of concentrated solar flux is achievable by using double paraboloid reflection, with a primary reflector to concentrate the sunlight, and a secondary reflector to homogenise the radiation flux. For that, three slightly different secondary reflectors were designed and manufactured, matching the specifications of the paraboloid concentrator of the SF60 solar furnace located in PSA—Plataforma Solar de Almería, which was used as primary reflector. Starting from preliminary simulations of the optical apparatus, the secondary geometries were selected and then the reflectors were manufactured from 7075-T6 aluminium alloy, using conventional and CNC machining technologies, with further processing to achieve a mirror-like finish. The results obtained from solar irradiation tests corroborate that the “double paraboloid reflection” methodology proposed in previous theoretical works seems to be technically feasible and can be a solution for obtaining homogeneously distributed fluxes of highly concentrated solar radiation.

Este número de Inmaterial introduce una serie de cambios, construidos sobre el increíble trabajo acumulado durante los últimos años. En este sentido, queremos agradecer a la anterior dirección de la revista, especialmente a la profesora y antropóloga Dra. Mara Martínez Morant y Dr. Ramón Rispoli. También debemos agradecer al equipo que ha estado detrás de este proyecto desde sus inicios. Sin su apoyo y constante implicación, no estaríamos hoy aquí. Inauguramos así una nueva etapa en la trayectoria de Inmaterial, y este número trata de dar cuenta de este cambio, como ya sugería claramente la convocatoria de contribuciones. Hemos basado esta primera convocatoria en una afirmación muy abierta del filósofo estadounidense Alva Nöe: “Somos diseñadores por naturaleza”. Se trata de una afirmación muy sencilla, pero atrevida, en tiempos tan complejos como los nuestros, caracterizados por una conceptualización confusa en diferentes campos al mismo tiempo. Nuestro nuevo número de Inmaterial, diseño, arte y sociedad, propone un territorio abierto a las formas y prácticas contemporáneas realizadas en el contexto de las instituciones académicas, dando espacio para abordar los aspectos metodológicos, normales y técnicos que implica la investigación en diseño y arte. Entendemos este formato formal y pragmático como una línea de fuga. Vemos este número como un escenario abierto, que incluye una multiplicidad de territorios de exploración basados en prácticas, en experiencias, en vivencias. Este número reúne una serie de artículos que exploran diferentes aspectos del pensamiento y la práctica del diseño en el presente. Esta es nuestra tentativa. Estas contribuciones nos invitan a una lectura lenta, una lectura que debe llevarnos “más allá del cálculo al pensamiento” (Boulous, 2017: 16). Esperamos que nuestras intenciones se sustenten en esta nueva línea de pensamiento, y les invitamos a “esperar a que se asiente el polvo de la lectura” (Woolf: 1925, 266).

Our new issue of Inmaterial, design, art, and society, proposes a territory open to contemporary forms and practices carried out in the context academic institutions, giving space to address the methodological, formal, and technical aspects involved in design and art research. We see this formal and pragmatical format as a line of flight. We see this issue as an open arena, including a multiplicity of exploratory territories based on practices, on experiences, on livings. In this issue you will find a series of articles that explore different aspects of design thinking and practice in the present. This is our attempt. These contributions invite us to a slow reading, a reading that should move us “beyond calculation to thought” (Boulous, 2017: 16). We hope that our intentions will be sustained by this new line of thought, and we invite you to “wait for the dust of reading to settle” (Woolf: 1925, 266).

The ornamental stone industry has always played an important role in the world economy. Polishing the slabs to increase their gloss is important to enhance the beauty and richness of these natural materials. Many industrial polishing machines rely on a rotating head’s movement along zigzag trajectories (controlled by belt, transverse and rotational speeds), to erode the surface as stochastically as possible (to avoid scratches and other visual defects caused by paths that are too symmetrical). Optimizing (and automatizing) these three speeds together therefore represents a significant gain for the industry, in time, energy, and quality of product. In this work we show that this optimization can be accomplished by fulfilling these conditions: (1) the displacement of the polishing head after a single zigzag movement should be smaller than its diameter; and (2) the displacement of the polishing head after a single rotation should be smaller than its radius. To assess the validity of these two conditions, we studied the polishing activity using experiments based on gloss measurements of the polished stone and computer simulations based on the geometric contacts between the tool and the stone. We concluded that: (i) a clear correlation can be established between experimental and simulation data; (ii) the two displacement parameters represent an effective way to control the quality and efficiency of the polishing process; and (iii) there is a limit to the gloss acquired through polishing processes, thus polishing above a given threshold decreases the efficiency without increasing the quality. The correspondence between experimental and modelling results opens the door to further optimizations of these polishing processes in the future.

This work compares the performance of optical lenses made of silica glass or borosilicate glass (BK-7) when submitted to high-flux radiation emitted by a xenon arc lamp or provided by a high-concentration solar tower. Each irradiation test lasted for 60 min, with continuous monitoring of the radiation-flux incident on the lenses and the temperature generated in their vicinity. All silica glass lenses showed a good performance with both irradiation sources, xenon arc lamp and natural solar radiation, contrary to what was observed with the lenses made of borosilicate glass which fractured when irradiated with a xenon arc lamp. The negative behavior observed with the borosilicate lenses is attributed to the fact that the radiation spectrum of a xenon arc lamp contains certain wavelengths, in the near ultraviolet (UV) region, that are not present in the natural solar radiation spectrum at sea level.

Using a high-flux solar furnace, loosely compacted powders of Va-group transition metal (V, Nb, and Ta) were reacted with stream of NH3 gas (uncracked NH3 gas) being heated by concentrated solar beam to a temperature (T) range between 600 and 1000 °C. From V, sub-nitride V2N (γ phase) and hypo-stoichiometric mono-nitride VN possessing fcc (face-centered cubic) crystal lattice structure (δ phase) were synthesized. On the other hand, in the reaction product from Nb and Ta, hexagonal mono-nitride phase with N/M atom ratio close to 1 (ε phase) was detected. The reaction duration was normalized to be 60 min. In a conventional industrial or laboratory electric furnace, the synthesis of mono-nitride phase with high degree of crystallinity that yield sharp XRD peaks for Va-group metal might take a quite long duration even at T exceeding 1000 °C. In contrast, mono–nitride phase MN of Va-group metal was synthesized for a relatively short duration of 60 min at T lower than 1000 °C being co-existed with lower nitride phases.

Porosity is a characteristic present in most sintered materials, full densification only being achieved in special cases. For some sintered materials, porosity is indeed a desired characteristic, serving for the intended application of the material. In any case, the porosity present in materials can have a strong effect on some of their properties, both structural and functional. In this paper, some of the expressions proposed to describe the influence of the total porosity on the effective properties of sintered materials are examined. Moreover, a universal expression (with two fitting parameters) valid to satisfactorily represent all the analysed behaviours is proposed. One of these parameters can be assimilated to the tap porosity of the powders used to manufacture the material. The properties examined were elastic moduli, ultimate strength, thermal and electrical conductivities, magnetic characteristics, and other properties directly related to these ones. The study is valid for sintered materials, both metallic and ceramic, with a homogeneous and non-texturised microstructure.

Solar radiation homogenizers are multi-mirror devices that try to reshape the solar radiation distribution coming from a concentrator, so that, after passing through the homogenizer, the light flux becomes as much evenly distributed as possible. The optical behavior of these multi-reflective devices is complex and still ill-understood. The geometry of the concentrator defines the features of the concentrated flux and then the characteristics of a particular homogenizer must be chosen according to the envisaged use. In this work, we developed and used optical ray-tracing software to investigate how the homogenizer’s optical output is affected by the following homogenizer’s characteristics: (i) Number of reflecting surfaces; (ii) total length; (iii) position (relative to focal plane); and (iv) tilt angle (inclination) of reflecting surfaces. The obtained results provide valuable information for the use of these optical devices and may contribute to the development of more efficient strategies for homogenization of concentrated radiation generated by high-flux solar furnaces.

Seafood products are perceived as healthy foods. However, several species of seafood are still not fully utilized for different reasons or can be valued outside the original locale, if issues with the short shelf-life and/or the preparation/presentation form are overcome, e.g., gray triggerfish, Balistes capriscus. Consumed mostly fresh, its flesh is of excellent quality. We studied the effect of different types of packaging (in air (AIR), vacuum (VP), and modified atmosphere (MAP)) on physicochemical (color and texture, pH, and total volatile basic nitrogen), microbiological (total viable count, psychrotrophic, sulphide-reducing bacteria, and acid-lactic bacteria), and sensory qualities, and shelf-life of gray triggerfish fillets stored at refrigeration temperature for 15 days. The samples were analyzed on days 0 (fresh fish), 5, 10 (8 and 12 for sensory analysis), and 15 after filleting and packaging. During the trial, fillets became lighter (increased L*) and yellower (b* >> 0) with time of storage. Distinct patterns were observed for pH among treatments. Unexpectedly, the increasing trend observed in the texturometer-derived hardness of VP and MAP fillets, contrasted with the sensory assessment, wherein panelists perceived a clear softening of fillets. VP delayed and MAP inhibited the increase in TVB-N contents of fillets compared to fillets packed in AIR. Total viable count and psychrothropic bacteria of fillets in AIR exceeded the conventional limit of 7 log(CFU/g) on day 10, while in fillets packed in VP and MAP, their abundance remained below that limit during the trial. The organoleptic attributes of fillets perceived by a sensory panel changed significantly in all treatments during the storage trial. Willingness to consume the fillets decreased constantly in AIR and MAP, but not in VP fillets. Considering primarily sensory, but also biochemical and microbiological parameters, namely panelists’ rejection, total volatile basic nitrogen content, and total viable count and psychrotrophic bacteria abundance, the shelf-life of fillets packed in air was eight days. Vacuum and modified atmosphere packaging extended the shelf-life to 15 and 12 days, and thus can add value to this product. Future research regarding the VP and MAP of gray triggerfish fillets could involve the optimization of mixtures of gases use and/or the application of combined processes.

La investigación reflexiona sobre la práctica profesional docente del estudiante de matemática del IPMALA cursante de la Fase Integración Docencia Administrativa. Se muestra la realidad actual de la formación del docente de matemática, con la finalidad de divisar juicios oportunos dirigidos a los cambios curriculares que se vienen gestando. Se hace referencia a la visión teórica y legal que sustenta la práctica profesional docente en Venezuela. La metodología se centró en la descripción de las observaciones a un grupo de 15 futuros docentes de matemática en su práctica profesional. Los resultados muestran deficiencias en conocimientos matemáticos, planificaciones vacías en estrategias y en recursos innovadores, falta de competencias en evaluación de aprendizajes; y como positivo están: interés por mejorar la enseñanza, contextualización intra y extra-matemática, entre otros. Se sugiere la revisión del currículo de formación de profesor en matemática: que no fragmente lo

Comparisons between experimental data and ray-tracing simulation results are presented for the high-flux SF60 solar furnace available at the Plataforma Solar de Almeria, Spain, which has an estimated thermal power of 60 kW. Since an important issue in many applications of solar concentrated radiation is to obtain a radiation distribution that is as homogeneous as possible over the central working area, so-called radiation homogenisers were also used but the degree of success achieved is just satisfactory, as the results show. Finally, further modelling studies using ray-tracing simulations aiming to attain a homogenous distribution of flux by means of double reflexion using two paraboloid surfaces are presented.

Considering works published in the literature for more than a decade (period from January 2008 till June 2019), this paper provides an overview of recent applications of the so-called “solar furnaces”, their reactors, process chambers and related devices, aiming specifically at the processing of (solid) materials. Based on the author’s own experience, some prospects on future trends are also presented. The aim of this work is to demonstrate the tremendous potentialities of the usage of solar heat for materials processing, but also to reveal the necessity of further developing solar-driven high-temperature technologies (which are required to displace the use of electricity or natural gas). In particular, it is essential to improve the temperature homogeneity conditions inside reaction chambers for materials processing using solar heat. Moreover, new innovative modular systems, practical and flexible, for capture, concentration, control and conduction of concentrated solar radiation are suggested. Solar thermal technologies for the production of electricity, as well as solar thermochemical processes for production of gases or liquids, are outside the scope of this review.

This paper presents results on the research currently being carried out with the objective of developing new electrochemistry-based processes to produce renewable synthetic fuels from liquefied biomass. In the current research line, the gas mixtures obtained from the typical electrolysis are not separated into their components but rather are introduced into a reactor together with liquefied biomass, at atmospheric pressure and different temperatures, under acidified zeolite Y catalyst, to obtain synthesis gas. This gaseous mixture has several applications, like the production of synthetic 2nd generation biofuel (e. g., biomethane, biomethanol, bio-dimethyl ether, formic acid, etc.). The behaviour of operational parameters such as biomass content, temperature and the use of different amounts of acidified zeolite HY catalyst were investigated. In the performed tests, it was found that, in addition to the synthesis gas (hydrogen, oxygen, carbon monoxide and carbon dioxide), methane was also obtained. Therefore, this research is quite promising, and the most favourable results were obtained by carrying out the biomass test at 300 °C, together with 4% of acidified zeolite Y catalyst, which gives a methane volumetric concentration equal to 35%.

High-flux solar furnaces distributed throughout the world have been designed and constructed individually, i.e., on a one-by-one basis because there are several possible optical configurations that must take into account the geographical location and the maximum power to be attained. In this work, three ray-tracing models were developed to simulate the optical paths travelled by sun rays in solar furnaces of high concentration using as an example, the solar furnace SF60 of the Plataforma Solar de Almería, in Spain. All these simulation models are supported by mathematical constructions, which are also presented. The first model assumes a random distribution of sun rays coming from a concentrator with spherical curvature. The second model assumes that a random distribution of parallel rays coming from the heliostat is reflected by a concentrator with spherical curvature. Finally, the third model considers that the random parallel rays are reflected by a concentrator with a paraboloid curvature. The three models are all important in optical geometry, although the paraboloid model is more adequate to optimize solar furnaces. The models are illustrated by studying the influence of mirror positioning and shutter attenuation. Additionally, ray-tracing simulations confirmed the possibility to attain homogenous distribution of flux by means of double reflexion using two paraboloid surfaces.

El dominio del idioma inglés por parte del personal médico cubano ha constituido una preocupación constante de la política educacional para las escuelas de medicina en Cuba. La impartición de la disciplina inglés ha ido evolucionando y sufriendo cambios según se han perfeccionado los planes de estudio de las diferentes carreras, lo cual se ha valorado a través de una revisión bibliográfica. Desde 1970 Cuba está enviando personal médico a los países de América Latina y el Medio Oriente, pero en especial al continente africano, lo que ha obligado a perfeccionar aún más la preparación del personal médico, en especial en el idioma inglés, debido a los requisitos que se precisan para laborar en esos países. Es por ello que la metodología que se utiliza para impartir la docencia de la disciplina de Inglés con propósitos específicos debe perfeccionarse también, buscando métodos y alternativas que enriquezcan el proceso enseñanza - aprendizaje y lo hagan más eficiente, proporcionando herramientas útiles al futuro egresado para su desempeño profesional en el idioma Inglés y también para su propia superación. El presente trabajo brinda un ejemplo de estrategia metodológica aplicada a la asignatura Inglés VII correspondiente al 4to año de la carrera de medicina, lo cual enriquecerá el desarrollo del proceso enseñanza-aprendizaje en ese nivel, contribuyendo al desarrollo eficaz de las habilidades lingüísticas del estudiante y con el objetivo de propiciar una eficaz competencia comunicativa en el futuro egresado.The mastery of English language by Cuban medical personnel has been a permanent cause of concern for the educational politics in Cuban medical schools. The teaching of English language has evolved and changed together with the improvement of the syllabuses in the different degrees; which has been assessed by means of a literature review. Long since 1970, Cuba is sending medical personnel to Latin-American and Middle Eastern countries, particularly to the African continent, requiring a better preparation of these personnel, specifically in English language. Due to the requirements needed to work in these countries, the methodology in use to teach English language with specific purposes must be also improved seeking for methods and alternatives to enrich teaching-learning process to make it more efficient, providing at the same time useful tools to the future graduates for the professional performances in English as well as self-training. The present paper offers an example of a methodological strategy which is applied to the English language subject taught to the medical students in 4th academic degree; the goal is: to enrich the development of the teaching-learning process in this level, and to contribute to an effective acquisition of linguistic skills to achieve communicative competence in the future graduate.

Este glosario se confeccionó con el objetivo de brindarles a los estudiantes de Ciencias Médicas y a los profesionales de la salud en general, información acerca de los medicamentos de mayor uso, mostrando su nombre en español e inglés, la correcta pronunciación, sus indicaciones y tratamiento. Este compila 142 medicamentos, ordenados alfabéticamente con una traducción al español de sus correspondientes categorías y aplicaciones. Algunos de los medicamentos compilados en este folleto fueron impartidos en las clases de inglés con fines médicos en 4to año de la carrera de Medicina durante este curso, y ha sido de gran interés y utilidad para los futuros profesionales. Se concluye que el folleto es de gran utilidad porque no solo puede servir de referencia a los estudiantes de Ciencias Médicas, sino también a todo el personal de la salud o a cualquier persona interesada en el tema, incluyendo a profesores de inglés de la institución.Aimed at providing medical students and health professionals information about the most used medications showing their names in Spanish and English as well as the correct pronunciation, indications and treatment, a glossary of pharmacological terms was made. This compiles 142 medications in alphabetical order having a translation into Spanish of their corresponding categories and applications. Some of the medications compiled in this pamphlet were taught in the English lessons with medical purposes in the 4th academic year of the medical major during this course, being of great interest and usefulness for the future health professionals. Concluding that this glossary can be a tool of reference for medical students and for all health personnel or any other people interested in the topic, including professors of English in the institution.