Use of ash from sewage sludge in the preparation of desulfurant sorbents

This work aims to develop new uses for sewage sludge, which is a byproduct of municipal wastewater treatment plants, by examining the calcination of this waste, the characterization of ashes is obtained, and its use to prepare desulfurant sorbents. Samples of sewage sludge were obtained from a local municipal wastewater treatment plant. This plant applies a pre-treatment followed by a biological treatment, where anaerobic digestion and centrifugation reduces the sludge. Three samples were characterized (in humidity, volatile and fixed solids content), dried, and ignited at two temperatures, 550 and 750 C. The composition of the ash obtained at both ignition temperatures was studied by x-ray fluorescent spectroscopy and the BET specific surface area of the two ashes and of the prepared sorbents was measured. Ash composition was similar for the two temperatures tested, where the components were Si, Ca, Al, Fe, P, S, Mg, K, Cl, Zn and Ti. BET specific surface area values indicate that the lower temperature of calcination produces ash with the highest SSA values (18 m2/g against near 10 m2/g). Preparation of desulfurant sorbents was carried out by mixing the ash with CaO or Ca(OH)2 at room temperature and different experimental conditions. The BET SSA of the prepared desulfurant sorbents showed higher values for the sorbents prepared with the ashes obtained at the lowest temperature. The behaviour of the ash and the prepared sorbents was tested in a fixed bed reactor at 58 C with a flue gas containing 5000 ppm of SO2 with a relative humidity of 55%. Results in the desulfurization process show that the calcium from the sludge seems more efficient than the calcium added as CaO or Ca(OH)2 to prepare the sorbents

Elimination of scan impedance anomalies in ultra-wide band phased arrays of differentially fed tapered slot antenna elements

Scan impedance anomalies are associated to phased arrays. There are different phenomena in order to explain these scan blindnesses produced when the array scans at one frequency and one angle. The most popular technique for eliminating these scan blindnesses is based on the use of electric walls in the grid of the two dimensional array. In this paper we present a dual polarized ultra-wide band array based on “bunny ears” antennas from 0.3 GHz to 1 GHz which presents scan blindness. We analyze the cause of the anomaly and present a technique non based on electric walls in order to avoid the scan blindness with a small increase in the noise figure of the array

Diseño de amplificadores diferenciales de bajo ruido para antenas uwb en la banda baja del proyecto Ska

Differential amplifiers can be an appropriate solution in the implementation of radio astronomy receivers, due to their efficient interference and harmonic isolation. In this paper, two different topologies are presented. The first one consists of two single ended amplifiers in a balanced topology. The second one is formed by cascading two simple differential stages. Both circuits operate in the 300MHz to 1GHz bandwidth. Firstly, gain and noise characterizations of each amplifier have been done. Lastly, noise analysis of the whole reception system, formed by the antenna and the differential amplifiers, is presented

Contribución al conocimiento de la pteridoflora de Andalucía: sobre el género Ophioglossum L. en Almería

Contribution to the knowledge about Andalusian pteridophyte flora: on the genus Ophiglossum L. inAlmeríaPalabras clave. Biodiversidad, Corología, Montañas Béticas, Sureste ibérico.Key words. Biodiversity, Chorology, Baetic Ranges, South-eastern Iberian Peninsula

Diseño y Caracterización de un Array Activo de Banda Ancha para Radioastronomía

The Square Kilometre Array (SKA) radio-telescope will become a reality in 2020. Nowadays, many research groups are validating the technologies that will be necessary to build this enormous instrument. In order to cover the bandwidth between 70 MHz and 10 GHz, different antenna array designs and configurations will be used. This paper presents the design and characterization of a planar aperture array based on bunny-ear antennas, whose design is proposed to cover the midfrequency range of the telescope (from 300 to 1000 MHz). One of the main advantages of the present solution is its fully differential nature, which avoids the use of passive baluns, although it requires some especial considerations during the design and measurement processes

Broadband active differential array for the mid-frequency SKA band

This paper presents the design and characterization process of an active array demonstrator for the mid-frequency range (i.e., 300 MHz-1000 MHz) of the future Square Kilometre Array (SKA) radio telescope. This demonstrator, called FIDA3 (FG-IGN: Fundación General Instituto Geográfico Nacional - Differential Active Antenna Array), is part of the Spanish contribution for the SKA project. The main advantages provided by this design include the use of a dielectric-free structure, and the use of a fully-differential receiver in which differential low-noise amplifiers (LNAs) are directly connected to the balanced tapered-slot antennas (TSAs). First, the radiating structure and the differential low-noise amplifiers were separately designed and measured, obtaining good results (antenna elements with low voltage standing-wave ratios, array scanning capabilities up to 45°, and noise temperatures better than 52 K with low-noise amplifiers at room temperature). The potential problems due to the differential nature of the proposed solution are discussed, so some effective methods to overcome such limitations are proposed. Second, the complete active antenna array receiving system was assembled, and a 1 m2 active antenna array tile was characterized

Ameliorative Effect of the Oral Administration of Chuquiraga spinosa in a Murine Model of Breast Cancer Induced with 7,12-Dimethylbenz[a]anthracene (DMBA)

Objective: To determine the ameliorative effect of the ethanolic extract of Chuquiraga spinosa (ChS) on 7,12-Dimethylbenz[a]anthracene (DMBA)-induced breast cancer in rats. Methods: 36 female Holztman rats were divided into 6 groups. I) The negative control group received physiological saline (PS). II) ChS-200 group received 200 mg/kg of ChS. III) DMBA group was induced with DMBA (20 mg/Kg) dissolved in PS and administrated orally for 15 weeks. IV) DMBA + ChS-50 group, V) DMBA + ChS-250 group, and VI) DMBA + ChS-500 group, which received the extract orally for 15 weeks after DMBA induction. All data were expressed as mean and standard deviation. One-way analysis of variance (ANOVA) followed by Dunnet test was carried out to compare the mean value of different groups Histopathological analysis was evaluated by using Image J software. Results: Hematology showed that the triglyceride level was significantly lowered (P< 0.01) and high-density lipoprotein (HDL) level was significantly increased (P <0.01) in groups III, IV and V. Also, ChS extract significantly lowered the C reactive protein (CRP) level (P <0.01) and malondialdehyde level (P<0.05). There was a significant decrease in the frequency of DMBA-induced micronucleated polychromatic erythrocyte (P<0.01). Conclusions: Chuquiraga spinosa showed an ameliorative effect on DMBA-induced breast cancer in rats as well as antioxidant, antitumor and antigenotoxic properties.Revisión por pare

Ameliorative Effect of the Oral Administration of Chuquiraga spinosa in a Murine Model of Breast Cancer Induced with 7,12-Dimethylbenz[a]anthracene (DMBA)

Objective: To determine the ameliorative effect of the ethanolic extract of Chuquiraga spinosa (ChS) on 7,12-Dimethylbenz[a]anthracene (DMBA)-induced breast cancer in rats. Methods: 36 female Holztman rats were divided into 6 groups. I) The negative control group received physiological saline (PS). II) ChS-200 group received 200 mg/kg of ChS. III) DMBA group was induced with DMBA (20 mg/Kg) dissolved in PS and administrated orally for 15 weeks. IV) DMBA + ChS-50 group, V) DMBA + ChS-250 group, and VI) DMBA + ChS-500 group, which received the extract orally for 15 weeks after DMBA induction. All data were expressed as mean and standard deviation. One-way analysis of variance (ANOVA) followed by Dunnet test was carried out to compare the mean value of different groups Histopathological analysis was evaluated by using Image J software. Results: Hematology showed that the triglyceride level was significantly lowered (P< 0.01) and high-density lipoprotein (HDL) level was significantly increased (P <0.01) in groups III, IV and V. Also, ChS extract significantly lowered the C reactive protein (CRP) level (P <0.01) and malondialdehyde level (P<0.05). There was a significant decrease in the frequency of DMBA-induced micronucleated polychromatic erythrocyte (P<0.01). Conclusions: Chuquiraga spinosa showed an ameliorative effect on DMBA-induced breast cancer in rats as well as antioxidant, antitumor and antigenotoxic properties

Solar photovoltaic technology in isolated rural communities in Latin America and the Caribbean

The main characteristics of photovoltaic (PV) energy and its current development in Latin American and Caribbean countries (LAC); its impact on the electrification of homes, health institutions, and schools in isolated or difficult-to-access communities; and, the advantages thereof are presented and discussed by replacing the use of traditional fuels such as firewood and kerosene in order to improve inhabitants ’health as well as reducing CO2 emissions. Countries like Nicaragua, Peru, Brazil, Argentina, and Chile stand out for their growing PV energy development in the region. A case study of the electrification process by PV systems shows very positive changes are manifested in terms of improving the quality of life of the inhabitants, and especially their physical and mental health state. In addition, CO2 emission reductions from electrifying 216 houses in the nine communities reach an annual amount of 2,164.19 t/yr, reducing firewood consumption by 2,123.39 t/yr and kerosene consumption by 40.80 t/yr However, LAC countries must adopt laws and regulations that regulate the use of PV energy, with an emphasis on recycling systems at the end of their life cycle

Nueva citas para la flora de la provincia de Almería (Sureste Ibérico, España)

Three new floristic records are presented in this work including one new species for Andalucia (Tamarix dalmatica), one new species for the province of Almer&iacute;a (Filago hispanica) and a confirmation for this province (Orobanche ballotae).Se presentan tres citas flor&iacute;sticas que suponen, una novedad para Andaluc&iacute;a (Tamarix dalmatica), una novedad la provincia de Almer&iacute;a (Filago hispanica) y una confirmaci&oacute;n para dicha provincia (Orobanche ballotae)