Effect of Carbon Dioxide Concentration on the Growth Response of Chlorella vulgaris Under Four Different Led Illumination

This experiment examined the growth response of Chlorella vulgaris exposed to CO2 concentrations increasing from ambient to 8.5% and under white, blue, red and red-blue lights after 15 days incubation. Biomass production increased with increasing CO2 concentrations under all light sources. The highest biomass production, 1.59 g L-1, was obtained when the algae were supplied with 8.5% CO2 and exposed to white light. Biomass production under blue, red and red+blue light was 1.53 g L-1, 0.45 g L-1 and 1.27 g L-1, respectively. The research suggests that C. vulgaris is not able to adapt production of its photosynthetic pigments to absorb light sources different that it is normally has evolved to

An absolute calibration system for millimeter-accuracy APOLLO measurements

Lunar laser ranging provides a number of leading experimental tests of gravitation -- important in our quest to unify General Relativity and the Standard Model of physics. The Apache Point Observatory Lunar Laser-ranging Operation (APOLLO) has for years achieved median range precision at the ~2 mm level. Yet residuals in model-measurement comparisons are an order-of-magnitude larger, raising the question of whether the ranging data are not nearly as accurate as they are precise, or if the models are incomplete or ill-conditioned. This paper describes a new absolute calibration system (ACS) intended both as a tool for exposing and eliminating sources of systematic error, and also as a means to directly calibrate ranging data in-situ. The system consists of a high-repetition-rate (80 MHz) laser emitting short (< 10 ps) pulses that are locked to a cesium clock. In essence, the ACS delivers photons to the APOLLO detector at exquisitely well-defined time intervals as a "truth" input against which APOLLO's timing performance may be judged and corrected. Preliminary analysis indicates no inaccuracies in APOLLO data beyond the ~3 mm level, suggesting that historical APOLLO data are of high quality and motivating continued work on model capabilities. The ACS provides the means to deliver APOLLO data both accurate and precise below the 2 mm level.Comment: 21 pages, 10 figures, submitted to Classical and Quantum Gravit

APOLLO clock performance and normal point corrections

The Apache Point Observatory Lunar Laser-ranging Operation (APOLLO) has produced a large volume of high-quality lunar laser ranging (LLR) data since it began operating in 2006. For most of this period, APOLLO has relied on a GPS-disciplined, high-stability quartz oscillator as its frequency and time standard. The recent addition of a cesium clock as part of a timing calibration system initiated a comparison campaign between the two clocks. This has allowed correction of APOLLO range measurements--called normal points--during the overlap period, but also revealed a mechanism to correct for systematic range offsets due to clock errors in historical APOLLO data. Drift of the GPS clock on ~1000 s timescales contributed typically 2.5 mm of range error to APOLLO measurements, and we find that this may be reduced to ~1.6 mm on average. We present here a characterization of APOLLO clock errors, the method by which we correct historical data, and the resulting statistics

New process to describe radiation damage at the molecular level. Application to I-125 seeds in water

ICPEAC 2015, Toledo, Spain on 22 –28 July 2015; http://www.icpeac2015.com/We present the first step of a general study on induced damage by 125I in water at the molecular level. Requirements for such a study are introduced and preliminary results on the emission spectra of 125I seeds are presented.This work was supported by MINECO (FIS2012-31230) and FCT/MEC, RaBBiT, PD-F,PD/00193/2012); UID/Multi/04378/2013 (UCIBIO); UID/FIS/00068/2013 (CEFITEC); and grant number SFRH/BD/52536/2014.Peer Reviewe

Towards Rechargeable Zinc-Air Batteries with Aqueous Chloride Electrolytes

This paper presents a combined theoretical and experimental investigation of aqueous near-neutral electrolytes based on chloride salts for rechargeable zinc-air batteries (ZABs). The resilience of near-neutral chloride electrolytes in air could extend ZAB lifetime, but theory-based simulations predict that such electrolytes are vulnerable to other challenges including pH instability and the unwanted precipitation of mixed zinc hydroxide chloride products. In this work, we combine theory-based simulations with experimental methods such as full cell cycling, operando pH measurements, ex-situ XRD, SEM, and EDS characterization to investigate the performance of ZABs with aqueous chloride electrolytes. The experimental characterization of near-neutral ZAB cells observes the predicted pH instability and confirms the composition of the final discharge products. Steps to promote greater pH stability and control the precipitation of discharge products are proposed.Comment: 13 pages, 12 figure

Methodology for automatic fault detection in photovoltaic arrays from artificial neural networks

This article presents a methodology for automatic fault detection in photovoltaic arrays. Due to the great importance in the construction of increasingly robust photovoltaic plants, automatic fault detection has become a necessary tool to extend the useful life of these plants, avoid system shutdowns and reduce serious safety problems. In the present study, nine possible faults are detected, caused by malfunction in the bypass and blocking diodes. The solution consists of training two models based on artificial neural networks, the first model is a binary classifier that detects whether or not a fault occurs, the second is a multiclass classifier that detects the fault type. The obtained models were trained from simulation data, in an architecture of 9 photovoltaic panels interconnected in three rows by three columns matrix (extendable to larger systems). The evaluation shows that the prediction system has a total accuracy of 92.95%. Finally, this methodology is intended to be implemented in Colombia, in zones with difficult access and not interconnected to the electricity grid, seeking to reduce corrective maintenance

Valores relacionados con sexualidad, alcoholismo y tabaquismo en adolescentes. Manual teórico-práctico para su desarrollo

Special project stretched on a qualitative paradigm frame and supported by an ethnographic method, it had propose to diagnose the values of 8th grade Basic School students enrolled in the subject of Health Education in relation to sexuality, alcoholism and smoking. An extensive interview of open questions was used for two adolescents of each sex as key informants to determine their thoughts, feelings and behavior that denote values based on the foresaid areas. Simultaneously the information collected from the interviews and the theory compiled was contrasted, which led to the conclusion that teenagers do not have a solid body of values to prevent unhealthy conduct. A theoretical-practical manual was written directed toward adolescents students acquiring knowledge in the treated areas that allow them to assume attitudes and responsible behavior without risks.Proyecto especial enmarcado en el paradigma cualitativo, apoyado en el método etnográfico, tuvo como propósito diagnosticar los valores de dos alumnos de ambos sexos, de octavo grado de Educación Básica, en relación con la sexualidad, el alcoholismo y tabaquismo. La entrevista en profundidad con preguntas abiertas permitió indagar los pensamientos, sentimientos y acciones que denotaran valores vinculados a los temas señalados. En el análisis de datos cualitativos se utilizó la técnica por categorización. Se contrastó simultáneamente la información obtenida de las entrevistas y la teoría recopilada, lo que permitió concluir que los adolescentes no poseen un cuerpo de valores sólido para prevenir conductas no saludables. Se elaboró un manual teórico-práctico dirigido a promover en los estudiantes adolescentes la adquisición de conocimientos y un conjunto de valores asociados que le permitan asumir actitudes y conductas responsables y sin riesgos en los temas investigados