Flight path analysis in sounding rocket “Libertador I” with computational simulation on three degrees of freedom

This paper presents obtained results from computer simulations in order to analyze the flight path of the sounding rocket Libertador I, developed in 2012 at the Fundación Universitaria Los Libertadores. The main aspects that affect the motion of a rocket are propulsion and aerodynamics effects. Numerical algorithms were implemented to value the thrust provided by the rocket motor as well as aerodynamic loads. Then, the differential equations of the motion are solved using the Runge-Kutta method, RK9. Trajectory and other numerical results are calculated from a code developed in FORTRAN. Finally, graphs of the flight path, curves of the vehicle velocity as function of time are presented. Also, the algorithm permits to determine the maximum altitude and possible impact sites.Facultad de Ingenierí

Flight path analysis in sounding rocket “Libertador I” with computational simulation on three degrees of freedom

This paper presents obtained results from computer simulations in order to analyze the flight path of the sounding rocket Libertador I, developed in 2012 at the Fundación Universitaria Los Libertadores. The main aspects that affect the motion of a rocket are propulsion and aerodynamics effects. Numerical algorithms were implemented to value the thrust provided by the rocket motor as well as aerodynamic loads. Then, the differential equations of the motion are solved using the Runge-Kutta method, RK9. Trajectory and other numerical results are calculated from a code developed in FORTRAN. Finally, graphs of the flight path, curves of the vehicle velocity as function of time are presented. Also, the algorithm permits to determine the maximum altitude and possible impact sites.Facultad de Ingenierí

Lessons learned from the field analysis of PV installations in the Saharawi refugee camps after 10 years of operation

Energy access at refugee camps is one of the main challenges to address in humanitarian response actions, especially on long-term situations. The lack of access to electricity depends, among other factors, on the local natural resources and available technologies. In this sense, solar photovoltaic is one of the most appropriate technologies, especially now with the decrease of the photovoltaic costs. But long-term performance, reliability and social acceptance must be ensured to facilitate the introduction of the technology and its rapid widespread in these humanitarian context. This work presents the results of a field study conducted at the Saharawi refugee camps, inspecting the photovoltaic systems installed in the health institutions after 10 years of use. Results show how despite the good initial system design and high quality of the PV components, the lack of training on operation and maintenance of the PV installations have led to a dramatic reduction of the lifetime of the systems. Strong training programs on basic photovoltaic concepts and operation and maintenance of systems are required to solve this problem and guarantee the long-term functioning of the installations.The authors acknowledge funding from the ‘Agencia Andaluza de Cooperación Internacional para el Desarrollo’ (AACID), project number 2014DEC008

Flight path analysis in sounding rocket “Libertador I” with computational simulation on three degrees of freedom

This paper presents obtained results from computer simulations in order to analyze the flight path of the sounding rocket Libertador I, developed in 2012 at the Fundación Universitaria Los Libertadores. The main aspects that affect the motion of a rocket are propulsion and aerodynamics effects. Numerical algorithms were implemented to value the thrust provided by the rocket motor as well as aerodynamic loads. Then, the differential equations of the motion are solved using the Runge-Kutta method, RK9. Trajectory and other numerical results are calculated from a code developed in FORTRAN. Finally, graphs of the flight path, curves of the vehicle velocity as function of time are presented. Also, the algorithm permits to determine the maximum altitude and possible impact sites.Facultad de Ingenierí

Genotype and environment interaction in Colombian Holstein cattle

The existence of Genotype-Environment Interactions among four regions of Colombia was investigated. The information was obtained from records of Holstein cattle in Cundinamarca (C), Valle del Cauca(V), Antioquia (A) and Nariño (N). A mixed models multivariate analysis methodology, applied to an animal model for repeated measures was used. Variance components were estimated by Derivative Free Restricted Maximum Likelihood algorithm (DFREML). Contemporary group (Herd-year) and genetic group of the sires (origin-year of birth) were fixed effects, and the genetic additive, permanent environment and temporary environment were included as random effects. Production records (n = 69464) of 25 608 daughters of 594 sires were used. Genetic correlation coefficients of milk production between regions were 0.70, 0.83, 0.73, 0.95, 0.97 and 0.99 for C-V, C-A, C-N, V-A, V-N and A-N, respectively. Different genetic, permanent environment and residual variances among areas were observed, but heritabilities and repetibilities were similar. Genotype and Environment Interaction exists, mainly between Cundinamarca and the other three regions

Use of some mathematical models to study the lactation curve of Murrah buffaloes and their crossbreeds under a semi-extensive system in the state of Sao Paulo

In the present study, five mathematical models, two of which were linear: linear hyperbolic (FLH) and quadratic logarithmic (FQL); and three non linear: parabolic exponential (FPE), incomplete gamma (FIG), and inverse polynomial (FIP), were used to determine which of them gave best fit to the mean lactation curve, using data from three buffalo herds of the Murrah breed and its crossbreds, under a semi-extensive production system employing twice daily milking. Information was obtained on 3267 lactations, including 27600 test day milk weights. Milk testing was done at 30-day intervals over the period from 1990 to 2001. Lactations utilized in the analysis were based on a minimum of four and maximum of nine test days. Criteria used to verify the goodness of fit of the curve generated by each model were: adjusted coefficient of determination (R2A), lack of fit test (LDF), and graphs of the distribution of residuals and of residual lag. The highest R2A 86.29%, was obtained with both FQL and FLH, which also yielded the lowest residuals and not significant results (P>.05) in the LOF test

Supplement: "Localization and broadband follow-up of the gravitational-wave transient GW150914" (2016, ApJL, 826, L13)

This Supplement provides supporting material for Abbott et al. (2016a). We briefly summarize past electromagnetic (EM) follow-up efforts as well as the organization and policy of the current EM follow-up program. We compare the four probability sky maps produced for the gravitational-wave transient GW150914, and provide additional details of the EM follow-up observations that were performed in the different bands