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

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

Enteric methane mitigation strategies for ruminant livestock systems in the Latin America and Caribbean region: a meta-analysis.

Latin America and Caribbean (LAC) is a developing region characterized for its importance for global food security, producing 23 and 11% of the global beef and milk production, respectively. The region?s ruminant livestock sector however, is under scrutiny on environmental grounds due to its large contribution to enteric methane (CH4) emissions and influence on global climate change. Thus, the identification of effective CH4 mitigation strategies which do not compromise animal performance is urgently needed, especially in context of the Sustainable Development Goals (SDG) defined in the Paris Agreement of the United Nations. Therefore, the objectives of the current study were to: 1) collate a database of individual sheep, beef and dairy cattle records from enteric CH4 emission studies conducted in the LAC region, and 2) perform a meta-analysis to identify feasible enteric CH4 mitigation strategies, which do not compromise animal performance. After outlier?s removal, 2745 animal records (65% of the original data) from 103 studies were retained (from 2011 to 2021) in the LAC database. Potential mitigation strategies were classified into three main categories (i.e., animal breeding, dietary, and rumen manipulation) and up to three subcategories, totaling 34 evaluated strategies. A random effects model weighted by inverse variance was used (Comprehensive Meta-Analysis V3.3.070). Six strategies decreased at least one enteric CH4 metric and simultaneously increased milk yield (MY; dairy cattle) or average daily gain (ADG; beef cattle and sheep). The breed composition F1 Holstein × Gyr decreased CH4 emission per MY (CH4IMilk) while increasing MY by 99%. Adequate strategies of grazing management under continuous and rotational stocking decreased CH4 emission per ADG (CH4IGain) by 22 and 35%, while increasing ADG by 22 and 71%, respectively. Increased dietary protein concentration, and increased concentrate level through cottonseed meal inclusion, decreased CH4IMilk and CH4IGain by 10 and 20% and increased MY and ADG by 12 and 31%, respectively. Lastly, increased feeding level decreased CH4IGain by 37%, while increasing ADG by 171%. The identified effective mitigation strategies can be adopted by livestock producers according to their specific needs and aid LAC countries in achieving SDG as defined in the Paris Agreement