Calibration of the EDGES High-Band Receiver to Observe the Global 21-cm Signature from the Epoch of Reionization

The EDGES High-Band experiment aims to detect the sky-average brightness temperature of the $21$-cm signal from the Epoch of Reionization (EoR) in the redshift range $14.8 \gtrsim z \gtrsim 6.5$. To probe this redshifted signal, EDGES High-Band conducts single-antenna measurements in the frequency range $90-190$ MHz from the Murchison Radio-astronomy Observatory in Western Australia. In this paper, we describe the current strategy for calibration of the EDGES High-Band receiver and report calibration results for the instrument used in the $2015-2016$ observational campaign. We propagate uncertainties in the receiver calibration measurements to the antenna temperature using a Monte Carlo approach. We define a performance objective of $1$~mK residual RMS after modeling foreground subtraction from a fiducial temperature spectrum using a five-term polynomial. Most of the calibration uncertainties yield residuals of $1$~mK or less at $95\%$ confidence. However, current uncertainties in the antenna and receiver reflection coefficients can lead to residuals of up to $20$ mK even in low-foreground sky regions. These dominant residuals could be reduced by 1) improving the accuracy in reflection measurements, especially their phase 2) improving the impedance match at the antenna-receiver interface, and 3) decreasing the changes with frequency of the antenna reflection phase.Comment: Updated to match version accepted by Ap

Results from EDGES High-Band: II. Constraints on Parameters of Early Galaxies

We use the sky-average spectrum measured by EDGES High-Band ($90-190$ MHz) to constrain parameters of early galaxies independent of the absorption feature at $78$~MHz reported by Bowman et al. (2018). These parameters represent traditional models of cosmic dawn and the epoch of reionization produced with the 21cmFAST simulation code (Mesinger & Furlanetto 2007, Mesinger et al. 2011). The parameters considered are: (1) the UV ionizing efficiency ($\zeta$), (2) minimum halo virial temperature hosting efficient star-forming galaxies ($T^{\rm min}_{\rm vir}$), (3) integrated soft-band X-ray luminosity ($L_{\rm X\,<\,2\,keV}/{\rm SFR}$), and (4) minimum X-ray energy escaping the first galaxies ($E_{0}$), corresponding to a typical H${\rm \scriptstyle I}$ column density for attenuation through the interstellar medium. The High-Band spectrum disfavors high values of $T^{\rm min}_{\rm vir}$ and $\zeta$, which correspond to signals with late absorption troughs and sharp reionization transitions. It also disfavors intermediate values of $L_{\rm X\,<\,2\,keV}/{\rm SFR}$, which produce relatively deep and narrow troughs within the band. Specifically, we rule out $39.4<\log_{10}\left(L_{\rm X\,<\,2\,keV}/{\rm SFR}\right)<39.8$ ($95\%$ C.L.). We then combine the EDGES High-Band data with constraints on the electron scattering optical depth from Planck and the hydrogen neutral fraction from high-$z$ quasars. This produces a lower degeneracy between $\zeta$ and $T^{\rm min}_{\rm vir}$ than that reported in Greig & Mesinger (2017a) using the Planck and quasar constraints alone. Our main result in this combined analysis is the estimate $4.5$~$\leq \log_{10}\left(T^{\rm min}_{\rm vir}/\rm K\right)\leq$~$5.7$ ($95\%$ C.L.). We leave for future work the evaluation of $21$~cm models using simultaneously data from EDGES Low- and High-Band.Comment: Accepted in Ap

Impact of counter-bore nozzle on the combustion process and exhaust emissions for light-duty diesel engine application

This is the author s version of a work that was accepted for publication in International Journal of Engine Research. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published as https://doi.org/10.1177/1468087418819250[EN] This article describes the main results of an investigation about counter-bore injector nozzle impact on the combustion process in a modern Euro 6 diesel engine. First, hydraulic and spray visualization tests have been performed, showing a potential advantage of such nozzle design in fuel-air mixing efficiency. Then, combustion performance has been assessed on a GM-designed 1.6-L four-cylinder engine. The engine has been installed on a dynamometric test bench and instrumented with an AVL cylinder pressure transducer for heat release rate analysis, as well as HORIBA MEXA gas analyzer for exhaust emissions and AVL 415 Smoke Meter. Engine efficiency and emissions have been analyzed on four different part-load steady-state points, representative of New European Driving Cycle and Worldwide harmonized Light duty Test Cycle certification cycles, and covering engine speeds from 1250 to 2000 r/min and brake mean effective pressure between 0.2 and 1.4 MPa. Results of indicated analysis show that counter-bore nozzles have significant differences in terms of pilot injection combustion at low load points, which in turn lead to a better ignition and shorter combustion of the main injection. In addition, an improvement of diffusive combustion is observed as load increases. Because of both, fuel consumption is reduced by approximately 1% with respect to a standard nozzle. Finally, an appreciable decrease in engine exhaust emissions has been recorded, especially in terms of particulate matter and hydrocarbon emissions. This reduction has been linked to the improvement of fuel-air mixing promoted by the counter-bore nozzle previously observed.The authors would like to thank General Motors Global Propulsion Systems-Torino S.r.l. for sponsoring the current work. Part of the equipment was purchased with the help of Generalitat Valenciana in project IDIFEDER2018 with title "Equipamiento de diagnostico optico de alta velocidad para estudiar procesos de inyeccion''.Payri, R.; De La Morena, J.; Monsalve-Serrano, J.; Pesce, FC.; Vassallo, A. (2019). Impact of counter-bore nozzle on the combustion process and exhaust emissions for light-duty diesel engine application. International Journal of Engine Research. 20(1):46-57. https://doi.org/10.1177/1468087418819250S4657201Kastengren, A. L., Tilocco, F. Z., Powell, C. F., Manin, J., Pickett, L. M., Payri, R., & Bazyn, T. (2012). ENGINE COMBUSTION NETWORK (ECN): MEASUREMENTS OF NOZZLE GEOMETRY AND HYDRAULIC BEHAVIOR. Atomization and Sprays, 22(12), 1011-1052. doi:10.1615/atomizspr.2013006309Payri, R., Viera, J. P., Gopalakrishnan, V., & Szymkowicz, P. G. (2016). The effect of nozzle geometry over internal flow and spray formation for three different fuels. Fuel, 183, 20-33. doi:10.1016/j.fuel.2016.06.041Postrioti, L., Malaguti, S., Bosi, M., Buitoni, G., Piccinini, S., & Bagli, G. (2014). Experimental and numerical characterization of a direct solenoid actuation injector for Diesel engine applications. Fuel, 118, 316-328. doi:10.1016/j.fuel.2013.11.001Payri, R., Gimeno, J., De la Morena, J., Battiston, P. A., Wadhwa, A., & Straub, R. (2016). Study of new prototype pintle injectors for diesel engine application. Energy Conversion and Management, 122, 419-427. doi:10.1016/j.enconman.2016.06.003Payri, R., Bracho, G., Marti-Aldaravi, P., & Viera, A. (2017). NEAR FIELD VISUALIZATION OF DIESEL SPRAY FOR DIFFERENT NOZZLE INCLINATION ANGLES IN NON-VAPORIZING CONDITIONS. Atomization and Sprays, 27(3), 251-267. doi:10.1615/atomizspr.2017017949Li, T., Moon, S., Sato, K., & Yokohata, H. (2017). A comprehensive study on the factors affecting near-nozzle spray dynamics of multi-hole GDI injectors. Fuel, 190, 292-302. doi:10.1016/j.fuel.2016.11.009Payri, R., Viera, J. P., Gopalakrishnan, V., & Szymkowicz, P. G. (2017). The effect of nozzle geometry over ignition delay and flame lift-off of reacting direct-injection sprays for three different fuels. Fuel, 199, 76-90. doi:10.1016/j.fuel.2017.02.075Yao, C., Geng, P., Yin, Z., Hu, J., Chen, D., & Ju, Y. (2016). Impacts of nozzle geometry on spray combustion of high pressure common rail injectors in a constant volume combustion chamber. Fuel, 179, 235-245. doi:10.1016/j.fuel.2016.03.097Hong, J. G., Ku, K. W., Kim, S. R., & Lee, C. W. (2010). EFFECT OF CAVITATION IN CIRCULAR NOZZLE AND ELLIPTICAL NOZZLES ON THE SPRAY CHARACTERISTIC. Atomization and Sprays, 20(10), 877-886. doi:10.1615/atomizspr.v20.i10.40Molina, S., Salvador, F. J., Carreres, M., & Jaramillo, D. (2014). A computational investigation on the influence of the use of elliptical orifices on the inner nozzle flow and cavitation development in diesel injector nozzles. Energy Conversion and Management, 79, 114-127. doi:10.1016/j.enconman.2013.12.015Taskiran, O. O., & Ergeneman, M. (2014). Effect of nozzle dimensions and fuel type on flame lift-off length. Fuel, 115, 833-840. doi:10.1016/j.fuel.2013.03.005He, Z., Guo, G., Tao, X., Zhong, W., Leng, X., & Wang, Q. (2016). Study of the effect of nozzle hole shape on internal flow and spray characteristics. International Communications in Heat and Mass Transfer, 71, 1-8. doi:10.1016/j.icheatmasstransfer.2015.12.002Salvador, F. J., de la Morena, J., Carreres, M., & Jaramillo, D. (2017). Numerical analysis of flow characteristics in diesel injector nozzles with convergent-divergent orifices. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, 231(14), 1935-1944. doi:10.1177/0954407017692220Baldwin, E. T., Grover, R. O., Parrish, S. E., Duke, D. J., Matusik, K. E., Powell, C. F., … Schmidt, D. P. (2016). String flash-boiling in gasoline direct injection simulations with transient needle motion. International Journal of Multiphase Flow, 87, 90-101. doi:10.1016/j.ijmultiphaseflow.2016.09.004Payri, R., Salvador, F. J., Gimeno, J., & Bracho, G. (2008). A NEW METHODOLOGY FOR CORRECTING THE SIGNAL CUMULATIVE PHENOMENON ON INJECTION RATE MEASUREMENTS. Experimental Techniques, 32(1), 46-49. doi:10.1111/j.1747-1567.2007.00188.xDesantes, J. M., Pastor, J. V., García-Oliver, J. M., & Pastor, J. M. (2009). A 1D model for the description of mixing-controlled reacting diesel sprays. Combustion and Flame, 156(1), 234-249. doi:10.1016/j.combustflame.2008.10.008PASTOR, J., JAVIERLOPEZ, J., GARCIA, J., & PASTOR, J. (2008). A 1D model for the description of mixing-controlled inert diesel sprays. Fuel, 87(13-14), 2871-2885. doi:10.1016/j.fuel.2008.04.017Payri, F., Molina, S., Martín, J., & Armas, O. (2006). Influence of measurement errors and estimated parameters on combustion diagnosis. Applied Thermal Engineering, 26(2-3), 226-236. doi:10.1016/j.applthermaleng.2005.05.00

Utilización del alga (Chondracanthus chamissoi) y cáscara de banano (Musa paradisiaca) en la reducción de arsénico en aguas subterráneas, La Colorada – Mórrope

El objetivo general de esta investigación fue determinar la eficiencia del uso de algas marinas (Chondracanthus chamissoi) y cáscara de plátano (Musa paradisiaca) en la reducción de Arsénico en aguas subterráneas procedentes de IRHS 54 (Inventario de recursos hídricos) del Centro Poblado La Colorada del Distrito de Morrope. La población para este estudio fue el IRHS 54, es decir, agua subterránea y la muestra fue de 20 litros. El alga (Chondracanthus chamissoi) fue recolectada en la playa Santa Rosa y la cáscara de banano (Musa paradisiaca) fue recolectada en el mercado Moshoqueque, luego se acondicionó, se secó, se trituró, se tamizó y fueron envasadas en unos recipientes para los respectivos tratamientos. Se realizó diversos tratamientos en prueba de jarras, con el alga (Chondracanthus chamissoi) y la cáscara de banano (Musa paradisiaca) por separado y luego con la mezcla de ambas, trabajando con un tamaño de partícula de 250µm, dosis de 6gr., 5gr., 4gr., 3gr., 2.5gr., 2gr., 1gr., 0.75gr., 0.5gr. y 0.25gr., tiempo de contacto 60min. y velocidad de 200rpm., todo el proceso fue realizado a temperatura ambiente. Se comprobó una vez más que el alga (Chondracanthus chamissoi) cómo la cáscara de banano (Musa paradisiaca) son eficientes para reducir concentraciones de Arsénico presente en el agua, pero más eficiente es la mezcla de ambas ya que se logró determinar que en el último tratamiento realizado con una dosis de 0.25gr. se logró adsorber el 99% de Arsénico presente en el agua, obteniendo una concentración final de 0.001mg/L