Identification and analysis of impact factors on the economic feasibility of photovoltaic energy investments

The introduction of environmental impact targets around the world has highlighted the need to adopt alternative sources of energy, which can supply the demand and mitigate the damage caused to the environment. Solar energy is one of the main sources of alternative energy, and is considered an abundant source of clean energy. However, to facilitate and encourage investors interested in the installation of photovoltaic energy systems for electricity production, it is essential to evaluate the factors that impact the economic viability of the projects. Therefore, the objective of this research is to present a systematic analytical framework, in order to identify and analyze the main factors that impact the financial feasibility of projects for the installation of photovoltaic energy plants. For this purpose, a systematic literature review was carried out, analyzing the main studies related to the topic and identifying the main factors that may financially affect investments in photovoltaic energy systems. From this review, 29 influencing factors were identified and separated into five categories, namely, location, economic, political, climatic and environmental, and technical factors. The main factors highlighted are the investment cost, power generation, operation and maintenance costs, solar radiation, lifetime, energy tariff, efficiency, electricity consumption, and interest and taxes. The results may assist policy makers, investors, researchers, and other stakeholders to identify the key factors that are being examined in the literature, and to evaluate which ones should be considered in their study to ensure the sustainable development of power generation through the solar source

Production of American lettuce cultivars under different colored shade nets

Email: [email protected] (autor de correspondencia)Shading nets are used to reduce the amount of radiant energy reaching crops. The objective of the work was to compare the influence of black and red shading nets on the production of nine American lettuce cultivars in the Autumn period under the conditions of the Central Department of Paraguay. The experiment was carried out in the Experimental Field of the Departmental Agronomic Center (CAD) in the Municipality of Julián Augusto Saldívar. The treatments consisted of the combination of two types of shading netting (red with 35% shade and black with 35% shade) and nine cultivars of American lettuce (Julia, Dora, Angelina, Tainá, Sun Valley, Betty, Lucy Brown, Mara, and Serena) totaling 18 treatments. The experiment consisted in a complete randomized block design, arranged in split blocks 2×9 (the color of shading netting was considered the main plot, and the lettuce cultivars as the secondary plot) with four repetitions. Each experimental unit consisted of four crop rows with seven plants. Plant diameter, plant height, head diameter and height, commercial number of leaves per plant, fresh mass, and commercial productivity were evaluated. The data were subjected to analysis of variance, and when differences were found, the means were compared by the Scott-Knott test at 5% probability. The results indicate that using the red netting with the Serena and Dora cultivars provides greater fresh mass and commercial production.Las mallas de sombra se utilizan para reducir la cantidad de energía radiante que llega a los cultivos. El objetivo de este trabajo fue comparar la influencia de las mallas sombreadoras negras y rojas en la producción de nueve cultivares de lechuga americana en el período otoñal en las condiciones del Departamento Central del Paraguay. El experimento se realizó en el Campo Experimental del Centro Agronómico Departamental (CAD), en el municipio de Julián Augusto Saldívar. Los tratamientos consistieron en una combinación de dos tipos de malla sombra (roja con 35% de sombra y negra con 35% de sombra) y nueve cultivares de lechuga americana (Julia, Dora, Angelina, Tainá, Sun Valley, Betty, Lucy Brown, Mara y Serena) totalizando 18 tratamientos. El diseño experimental fue en franjas en bloques completos al azar de 2×9 (las mallas de color fueron consideradas la parcela principal y los cultivares la parcela secundaria) y cuatro repeticiones. Cada unidad experimental constó de cuatro hileras de cultivo, con siete plantas. Se evaluó diámetro de planta, altura de planta, diámetro y altura de cabeza, número comercializable de hojas por planta, masa fresca y rendimiento comercializable. Los resultados fueron sometidos a análisis de varianza y, cuando se encontraron diferencias significativas, se usó la prueba de Scott-Knott al 5% de probabilidad para la comparación de medias. Los resultados indican que el uso de la red roja con los cultivares Serena y Dora proporciona mayor producción de masa fresca y comercializable.Consejo Nacional de Ciencia y TecnologíaPrograma Paraguayo para el Desarrollo de la Ciencia y Tecnología. Proyectos de investigación y desarroll

Lecciones desatendidas entorno a la epidemia de dengue en Argentina, 2009

Este articulo es una reflexión acerca del impacto de la epidemia 2009 en Argentina, con 26.000 afectados y seis muertes, y como las consecuencias pudieron haber sido mucho menores si hubiese existido dialogo y entendimiento entre epidemiología y política sanitaria. La falta de preparación, la descoordinación en la respuesta y el impacto sobre la población, confirman la brecha existente entre la evidencia científica y la toma de decisión política. La epidemiologia y la política sanitaria tienen distintas prioridades, distintos tiempos y distinta escala de valores. Las lecciones de la epidemia de 2009 deberían servir para acercar estos dos pilares de la salud publica de cara al beneficio de la comunidad, que al fin, es el objetivo común

OTIMIZAÇÃO DE PORTFÓLIOS: ANÁLISE DE EFICIÊNCIA

This article aims to analyze the behavior of a portfolio of assets selected by Data Envelopment Analysis (DEA), optimized by the Sharpe approach, and compare it to portfolios of assets obtained only by DEA or the Sharpe approach. To do that, we used the DEA model to assess the efficiency of shares of the São Paulo Stock Exchange (Bovespa), employing return, variance and other indicators such as input and output variables. Also, we used the Sharpe approach to optimize the portfolio composition. In the comparison of portfolios, we noted that the resulting combination of both models performed better than the portfolios optimized by only one of the models

Spread pattern of the first dengue epidemic in the city of Salvador, Brazil

<p>Abstract</p> <p>Background</p> <p>The explosive epidemics of dengue that have been occurring in various countries have stimulated investigation into new approaches to improve understanding of the problem and to develop new strategies for controlling the disease. The objective of this study was to evaluate the characteristics of diffusion of the first dengue epidemic that occurred in the city of Salvador in 1995.</p> <p>Methods</p> <p>The epidemiological charts and records of notified cases of dengue in Salvador in 1995 constituted the source of data. The cases of the disease were georeferenced according to census areas (spatial units) and epidemiological weeks (temporal unit). Kernel density estimation was used to identify the pattern of spatial diffusion using the R-Project computer software program.</p> <p>Results</p> <p>Of the 2,006 census areas in the city, 1,400 (70%) registered cases of dengue in 1995 and the spatial distribution of these records revealed that by the end of 1995 practically the entire city had been affected by the virus, with the largest concentration of cases occurring in the western region, composed of census areas with a high population density and predominantly horizontal residences compared to the eastern region of the city, where there is a predominance of vertical residential buildings.</p> <p>Conclusion</p> <p>The pattern found in this study shows the characteristics of the classic process of spreading by contagion that is common to most infectious diseases. It was possible to identify the epicenter of the epidemic from which centrifugal waves of the disease emanated. Our results suggest that, if a more agile control instrument existed that would be capable of rapidly reducing the vector population within a few days or of raising the group immunity of the population by means of a vaccine, it would theoretically be possible to adopt control actions around the epicenter of the epidemic and consequently reduce the incidence of the disease in the city. This finding emphasizes the need for further research to improve the technology available for the prevention of this disease.</p

Quantifying the Spatial Dimension of Dengue Virus Epidemic Spread within a Tropical Urban Environment

Global trends in population growth and human redistribution and movement have reshaped the map of dengue transmission risk, exposing a significant proportion of the world's population to the threat of dengue epidemics. Knowledge on the relative contribution of vector and human movement to the widespread and explosive nature of dengue epidemic spread within an urban environment is limited. By analyzing a very detailed dataset of a dengue epidemic that affected the Australian city of Cairns we performed a comprehensive quantification of the spatio-temporal dimensions of dengue virus epidemic transmission and propagation within a complex urban environment. Space and space-time analysis and models allowed derivation of detailed information on the pattern of introduction and epidemic spread of dengue infection within the urban space. We foresee that some of the results and recommendations derived from our study may also be applicable to many other areas currently affected or potentially subject to dengue epidemics

An evaluation of enhanced cooling techniques for high-heat load absorbers.

Many components of the storage ring and front ends in the third generation of light sources are subjected to high heat loads from intense x-rays. Temperature rises and thermal stresses in these components must be kept within acceptable limits of critical heat flux and low-cycle fatigue failure. One of the design solutions is to improve heat transfer to the cooling water either by increasing water velocity in the cooling channels or by using inserts, such as porous media, twisted tapes and wire springs. In this paper we present experimental and analytical results to compare various enhanced cooling techniques for conditions specific to heating from an x-ray fan

Design of a high-precision tunable double crystal monochromator

The design of high-precision tunable double crystal monochromator is described. Each crystal of the monochromator can be aligned independently by a double-axis gimbal mechanism providing rotations about two perpendicular axes. Two orthogonal linear actuators operate the gimbal mechanism via a connecting bar. The exit beam height is controlled by separate linear actuators that change the distance between the crystals along the beam axis. Vertical separation between the crystals may also be adjusted. Thermal deformations are minimized in this compact UHV compatible design by water cooling of the first crystal. 7 refs