ROS-based Controller for a Two-Wheeled Self-Balancing Robot

In this article, a controller based on a Robot Operating System (ROS) for a two-wheeled self-balancing robot is designed. The proposed ROS architecture is open, allowing the integration of different sensors, actuators, and processing units. The low-cost robot was designed for educational purposes. It used an ESP32 microcontroller as the central unit, an MPU6050 Inertial Measurement Unit sensor, DC motors with encoders, and an L298N integrated circuit as a power stage. The mathematical model is analyzed through Newton-Euler and linearized around an equilibrium point. The control objective is to self-balance the robot to the vertical axis in the presence of disturbances. The proposed control is based on a bounded saturation, which is lightweight and easy to implement in embedded systems with low computational resources. Experimental results are performed in real-time under regulation, conditions far from the equilibrium point, and rejection of external disturbances. The results show a good performance, thus validating the mechanical design, the embedded system, and the control scheme. The proposed ROS architecture allows the incorporation of different modules, such as mapping, autonomous navigation, and manipulation, which contribute to studying robotics, control, and embedded systems

The Social Impacts of Circular Strategies in the Apparel Value Chain; a Comparative Study Between Three Countries

The apparel value chain is essential for the livelihood of millions of workers around the globe. However, human rights violations and the lack of a sustained income by apparel workers demonstrate the poor working conditions present in this sector. Circular economy (CE) has been used by incumbent businesses and startups as a framework to achieve sustainability, thus contributing to its economic, environmental and social dimensions. However, there is a lack of knowledge on its social impact. Most of the literature assesses CE’s social impacts by focusing only on the number of jobs created. However, the majority of studies agree on the need to analyse further the quality and inclusivity aspects. This paper explores the social impact of the different circular strategies implemented in three countries. It assesses social impacts related to the quality of jobs, workers’ sustainable livelihood and gender equality and inclusion. Results corroborate that CE social ambition is low, and that current circular strategies follow the same feminisation and precariousness of working conditions found in the linear apparel value chain. Thus, policymakers and businesses alike need to strengthen their CE social ambition; coordinate policy and strategies with different countries stakeholders of the apparel value chain to minimise trade-offs; and safeguard a just circular transition. This research contributes to the body of literature on CE by introducing a social impact assessment framework for circularity called SIAF-CE⚥. Additionally, it provides evidence on the current CE social impact implemented by startups and incumbents in regional and global contexts

Calidad fermentativa y nutricional de ensilados de maralfalfa (Pennisetum sp.) a diferentes edades de corte y niveles de maíz molido

Effect of cutting age and level of ground corn grain inclusion were determined on nutritional and fermentative quality of maralfalfa silages (Pennisetum sp). Two cutting ages 48 and 60 (Days After Regrowth) and five levels of ground corn (0, 5, 10, 15 and 20%) were evaluated on pH, ammoniacal nitrogen (N-NH3), dry matter (DM), ash, crude protein (CP), ether extract (EE), hemicellulose, and cellulose; as well as in vitro dry matter digestibility (IVDMD). The data obtained were analyzed under a completely randomized design with factorial arrangement (2x5, two cutting ages anda five corn levels). In maralfalfa silage 48 DAR and 5% ground corn was obtained highest content of crude protein (12.2%; P ≤ 0.05), and was decreased the level ammoniacal nitrogen (0.06%; P ≤ 0.05), also was observed in maralfalfa silages 60 DAR that addition ground corn increased digestibility and decreased cellulose content. The addition of ground corn to silages improved nutritional and fermentative characteristics and reduced pH, and ammoniacal nitrogen in maralfalfa silages, which improved the conservation, quality and digestibility. Results indicate that the production of maralfalfa silage more the addition of ground corn can improve protein content and digestibility, becoming in an option to incorporate into feeding of livestock.Se determinó el efecto de la edad de corte y el nivel de maíz molido en la calidad fermentativa y nutricional de ensilados de maralfalfa (Pennisetum sp). Dos edades de corte, 48 y 60 días después del rebrote (DDR) y cinco niveles de maíz molido (0, 5, 10, 15 y 20%) fueron evaluados en pH, nitrógeno amoniacal (N-NH3), materia seca (MS), cenizas, proteína cruda (PC), extracto etéreo (EE), hemicelulosa y celulosa; como también digestibilidad in vitro de la materia seca (DIVMS). Los datos obtenidos fueron analizados bajo un diseño completamente al azar con arreglo factorial (2x5, dos edades de corte y 5 niveles de maíz). En el ensilado de maralfalfa a 48 DDR y 5 % de maíz molido se obtuvo el más alto contenido de proteína cruda (12.2 %; P ≤ 0.05) y se disminuyó el nivel de nitrógeno amoniacal (0.06 %; P ≤ 0.05), mientras que el ensilado de maralfalfa 60 DDR and 0 % de maíz molido tuvo más alto contenido de cenizas (18.3 %; P ≤ 0.05), también se observó en los ensilados de maralfalfa a 60 DDR que la adición de maíz molido incrementó la digestibilidad y disminuyó el contenido de celulosa. La adición de maíz molido a los ensilados mejoró las características fermentativas y nutricionales y redujo el pH y nitrógeno amonical en ensilados de maralfalfa, lo cual mejoró la conservación, calidad y digestibilidad. Los resultados indican que la producción de ensilado de maralfalfa más la adición de maíz molido pueden incrementar el contenido de proteína y digestibilidad, convirtiéndose en una opción para incorporar dentro de la alimentación del ganado.Fil: Faviola Ortiz Robledo. Universidad Juárez del Estado de Durango (México). Facultad de Agronomía y Zootecnia.Fil: Osvaldo Reyes Estrada. Universidad Juárez del Estado de Durango (México). Facultad de Agronomía y Zootecnia.Fil: Francisco Oscar Carrete Carreón. Universidad Juárez del Estado de Durango (México). Facultad de Agronomía y Zootecnia.Fil: Juan Fernando Sánchez Arroyo. Universidad Juárez del Estado de Durango (México). Facultad de Agronomía y Zootecnia.Fil: Esperanza Herrera Torres. Universidad Juárez del Estado de Durango (México). Facultad de Agronomía y Zootecnia.Fil: Manuel Murillo Ortiz. Universidad Juárez del Estado de Durango (México). Facultad de Agronomía y Zootecnia.Fil: Rigoberto Rosales Serna. Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias (México

Confiabilidade e validade de um instrumento que mede sete dimensões de percepção de segurança em estudantes de uma universidade pública

Introduction: Public security management involves the implementation of public policies that justify the guidance of the State in the prevention of crime and the administration of justice. However, citizen distrust of government action is evidenced by a growing insecurity perception reported by the literature in seven dimensions: territorial, national, public, human, citizen, private and Internet user. Objective: To establish reliability and validity of an instrument that measures the perception of territorial, national, public, human, citizen, private, and Internet user security. Method: Non-experimental, cross-sectional, exploratory study with a non-probabilistic selection of 320 students from a public university. Results: Reliability of the overall scale (alpha = 0.793), and territorial (alpha = 0.792), national (alpha = 0.709), public (alpha = 0.785), human (alpha = 0.782), citizen (alpha = 0.792), private (alpha = 0.794), and Internet user (alpha = 0.731) subscales, show sufficient internal consistency. The territorial security factor accounted for 22% of total variance. Based on adjustment and residual parameters ⌠χ2 = 135.34 (32 gl) p = 0.054; GFI = 0.995; CFI = 0.990; RMSEA = 0.003⌡, the null hypothesis of significant relationship among theoretical dimensions of security with respect to factors weighted was accepted. Conclusions: Inclusion and measurement of a dimension of self-control perception that would negatively and significantly correlate with the perception of territorial security would explain the factorial structure of the scale. Such model would be estimated by a confirmatory factorial analysis with unweighted least squares.Introducción: la administración de seguridad pública supone la instrumentación de políticas públicas que justifican la rectoría del Estado en la prevención del delito y la impartición de justicia. Sin embargo, la desconfianza ciudadana hacia la acción gubernamental se evidencia por una creciente percepción de inseguridad reportada por la literatura en siete dimensiones: territorial, nacional, pública, humana, ciudadana, privada e internauta. Objetivo: establecer la confiabilidad y la validez de un instrumento que mide la percepción de seguridad territorial, nacional, pública, humana, ciudadana, privada e internauta. Método: estudio no experimental, transversal y exploratorio con una selección no probabilística de 320 estudiantes de una universidad pública. Resultados: la confiabilidad de la escala general (alfa = 0,793) y de las subescalas territorial (alfa = 0,792), nacional (alfa = 0,709), pública (alfa = 0,785), humana (alfa = 0,782), ciudadana (alfa = 0,792), privada (alfa = 0,794) e internauta (alfa = 0,731) evidencian una consistencia interna suficiente. El factor de seguridad territorial explicó el 22% de la varianza total. A partir de parámetros de ajuste y residual ⌠χ2 = 135,34 (32gl) p = 0,054; GFI = 0,995; CFI = 0,990; RMSEA = 0,003⌡, se aceptó la hipótesis nula de relación significativa entre las dimensiones de seguridad teóricas con respecto a los factores ponderados. Conclusiones: la inclusión y medición de una dimensión de percepción de autocontrol que correlacionaría negativa y significativamente con la percepción de seguridad territorial explicaría la estructura factorial de la escala. Tal modelo se estimaría con un análisis factorial confirmatorio con mínimos cuadrados no ponderados.Introdução: a administração de segurança pública supõe a instrumentação de políticas públicas que justificam a direção do Estado na prevenção das atividades criminosas e a aplicação de justiça. No entanto, a desconfiança cidadã em relação à ação é observada em uma crescente percepção de insegurança reportada na literatura em sete dimensões: territorial, nacional, pública, humana, cidadã, privada e internauta. Objetivo: estabelecer a confiabilidade e a validade de um instrumento que mede a percepção de segurança territorial, nacional, pública, humana, cidadã, privada e internauta. Método: estudo não experimental, transversal e exploratório com uma seleção não probabilística de 320 estudantes de uma universidade pública. Resultados: a confiabilidade da escala geral (alfa = 0,793), e das sub-escalas territorial (alfa = 0,792), nacional (alfa = 0,709), pública (alfa = 0,785), humana (alfa = 0,782), cidadã (alfa = 0,792), privada (alfa = 0,794), e internauta (alfa = 0,731), demostram uma consistência interna suficiente. O fator de segurança territorial explicou 22% da variância total. A partir de parâmetros de ajuste e residual ⌠χ2 = 135,34 (32gl) p = 0,054; GFI = 0,995; CFI = 0,990; RMSEA = 0,003⌡, foi aceita a hipótese nula de relação significativa entre as dimensões de segurança teóricas em relação aos fatores ponderados. Conclusões: a inclusão e medição de uma dimensão de percepção de autocontrole que correlacionaria negativa e significativamente com a percepção de segurança territorial explicaria a estrutura fatorial da escala. Esse modelo seria calculado com uma análise fatorial confirmatória com mínimos quadrados não ponderados

Nutrient concentrations, in vitro digestibility and rumen fermentation of agro-industrial residues of Cannabis sativa L. as a potential forage source for ruminants

Este estudio tuvo como objetivo determinar la concentración de PC, EE, CNS, fibras, CFT, TC, CBD, THC, digestibilidad in vitro de materia seca y parámetros de fermentación ruminal de residuos agroindustriales de Cannabis sativa L. de dos procesos extractivos de cannabinoides, como fuente potencial de forraje en la alimentación de rumiantes. La flor de Cannabis sativa se expuso al proceso de extracción por prensado en frío (CPF) y extracción alcohólica (CEA); los residuos vegetativos obtenidos después de las extracciones se compararon con la flor cruda como testigo (FCC) utilizando un diseño completamente al azar y la prueba de Tukey para la comparación de medias. Los procesos extractivos disminuyeron el EE, CFT y cannabinoides (CBD y THC). En contraste, las fibras, CNS y digestibilidad, aumentaron después de los procesos extractivos en CPF y CEA. Del mismo modo, la degradabilidad  in vitro aumentó después  de ambos procesos  extractivos  por encima del 120 %, así como el período de latencia. Además, los protozoos aumentaron con CPF, pero no se observaron cambios en CEA. Asimismo, no se observaron cambios en las bacterias celulolíticas en CPF y CEA. Sin embargo, las bacterias totales se redujeron después de ambas extracciones. Además, el N-amoníaco en las fermentaciones ruminales disminuyó con CPF y CEA, mientras que los ácidos grasos volátiles totales aumentaron. Además, la producción de gas aumentó por encima del 75 % en CPF y CEA; sin embargo, no se observaron cambios en el período de latencia. Además, la producción de metano y CO2 aumentó por encima del 80 y 60 %, respectivamente, para CPF y CEA; estos aumentos se asocian positivamente con mejoras en las fermentaciones ruminales. En conclusión, el residuo agroindustrial de Cannabis sativa L. obtenido después de los procesos extractivos analizados puede surgir como una fuente potencial de forraje en la alimentación de rumiantes.This study aimed to determine the concentration of CP, EE, NSC, fibers, TPC, CT, CBD, THC, in vitro digestibility of dry matter and rumen fermentation parameters of agroindustrial residues of Cannabis sativa L. from two extractive processes of cannabinoids, as a potential source of forage in ruminants feeding. The flower of Cannabis sativa was exposed to cold-press extraction (CPC) and alcoholic extraction (AEC) process; vegetative residues obtained after extractions were compared to raw flower as a control (RFC) using a completely randomized design and Tukey’s test for means comparison. Extractive processes decreased EE, TPC and cannabinoids (CBD and THC). Otherwise, fibers, NSC and digestibility, increased after the extractive processes in CPC and AEC. Similarly, in vitro degradability increased after both extractive processes above 120 % as well as latency period. Additionally, protozoa increased with CPC but no changes were observed in AEC. Likewise, no changes were observed in cellulolytic bacteria in CPC and AEC. However, total bacteria were reduced after both extractions. Moreover, N-ammonia in ruminal fermentations decreased with CPC and AEC whereas total volatile fatty acids increased. In addition, gas production increased above 75 % in CPC and AEC; however, no changes were observed in latency period. Furthermore, methane and CO2 production increased above 80 and 60 %, respectively for CPC and AEC; these augmentations are positively associated with improvements in the ruminal fermentations. In conclusions, the agroindustrial residue of Cannabis sativa L. obtained after the analyzed extractive processes may arise as a potential forage source in ruminants feeding

Rendimiento y valor nutricional de tres variedades de sorgo dulce cultivadas en cuatro ambientes de Durango

El sorgo dulce muestra alto rendimiento de forraje para la alimentación de rumiantes. El objetivo fue evaluar el rendimiento y calidad forrajera de tres variedades de sorgo en Durango. En 2014, se evaluaron las variedades Lico, TOM 3 y Mercedes, en la Colonia Hidalgo (CH), Campo Experimental Valle del Guadiana (CEVAG), La Soledad (LS) y La Goma (LG). El diseño experimental fue completamente aleatorio con arreglo factorial y cinco repeticiones. Se evaluó forraje verde (FV), forraje seco (FS), proteína cruda (PC), digestibilidad verdadera in vitro (DIVMS), fibra detergente neutra (FDN), fibra detergente ácida (FDA), lignina (L), celulosa (Cel), hemicelulosa (HE), valor relativo (VRF) y calidad relativa del forraje (CRF). Se observaron diferencias significativas (P≤0.01 y 0.05) entre ambientes y variedades para FV, FS, L, VRF y CRF y entre ambientes para PC, FDN, FDA, CEL, HE y DIVMS. En CEVAG, se registró el mayor rendimiento de FV (75.9 t ha-1) y FS (12.4 t ha-1). El valor más alto de PC se obtuvo en LG (10 %); mientras que la DIVMS fue alta en LS (78.2 %) y más baja en LG (63.9 %). El contenido de L fue más alto en CH (6.3 %) y LG (6.2 %); mientras que, en LS fue de 3.4 %. Exceptuando LG, en todos los ambientes se obtuvo alta calidad forrajera (CRF= 106.7 a 135.0 %). El sorgo es una opción forrajera en Durango, aunque debe cuidarse la fecha de siembra y cosecha, control de insectos, riego y fertilización para incrementar el rendimiento y calidad nutricional

Exploring urban metabolism—Towards an interdisciplinary perspective

© 2017 The Author(s) The discussion on urban metabolism has been long dominated by natural scientists focussing on natural forces shaping the energy and material flows in urban systems. However, in the anthropocene human forces such as industrialization and urbanization are mobilizing people, goods and information at an increasing pace and as such have a large impact on urban energy and material flows. In this white paper, we develop a combined natural and social science perspective on urban metabolism. More specifically, innovative conceptual and methodological interdisciplinary approaches are identified and discussed to enhance the understanding of the forces that shape urban metabolism, and how these forces affect urban living and the environment. A challenging research agenda on urban metabolism is also presented

Urban energy systems within the transition to sustainable development : A research agenda for urban metabolism

The way we make sense of urban areas stands at a critical point. To reduce energy use in cities, we need to manage the way energy flows into, through and out the city. This paper starts with an overview on energy use at different levels of aggregation which allows us to outline emerging issues on urban metabolism for further research regarding urban energy systems. The research agenda focuses on five aspects: energy services, drivers for energy services, waste, data and dynamic modelling and governance. We give indications regarding the direction we think we should aspire to follow. The variety of themes within urban energy systems demands a coordinated and multidisciplinary research effort to improve our understanding of how the research of urban metabolism can contribute to achieve sustainable development

Exploring transitions towards sustainable construction : The case of near-zero energy buildings in the Netherlands

This paper examines the use of qualitative information in the construction of an agent- based model in order to study the growth of near-Zero Energy Buildings (nZEB's) in the Netherlands through the innovation systems perspective. Drawing on desktop research and semi-structured interviews, this paper offers two major findings. First, we observed that the difficulties to the development of nZEB's have been shaped by interaction and institutional barriers: the inner complexity of the building sector has decisively impacted on the growth of nZEB's. Second, exploring interviewees' understanding of the system via an agentbased model has brought fresh insights about the problem. Overall, this is a call for an interdisciplinary approach to understand the changes required for nZEB's in their path for a successful adoption. Agent-based computational modelling, complemented with knowledge that was elicited from several stakeholders within the building sector, has helped to inspect the implication of common beliefs in the course of shaping possible futures toward a transition to nZEB's