ABSTRACT: DIMSUB is a computer program to complement a decision support tool (DST) to effectively study different hydraulic design alternatives in microirrigation systems. We developed environments in Visual Basic for applications for Microsoft Excel® that allow specific step-by-step functions to be created for the design of irrigation subunits. Different alternatives can be considered, such as types of emitter, lateral and submain pipe sizes, different feeding points, irregular subunit shapes and topography slopes. Furthermore, specific uniformity criteria need to be considered to achieve efficient water applications and proper design systems. Lengths of run lateral and submain pipes, position of the hydrant connection, pressure head and head loss in pipes or pressure-compensating emitters can be assigned to evaluate the results and choose the best design alternative. This user-friendly tool to study hydraulic variables is expected to be a valuable aid for the decision-making process in designing irrigation systems. Some examples of practical cases under specific crop conditions to design drip irrigation subunits are given using DIMSUB.

Resumen El carcinoma de células ecrinas constituye un grupo de neoplasias raras de la piel, de crecimiento lento pero altamente invasor. Se presenta un caso de lesiones cutáneas múltiples con compromiso multifocal que concluye con la documentación histopatológica de esta condición. (Acta Med Colomb 2019; 44. DOI:https://doi.org/10.36104/amc.2019.1203).

Abstract Eccrine cell carcinoma constitutes a group of rare skin malignancies which are slow-growing but highly invasive. A case of multiple skin lesions with multifocal involvement, concluding with the histopathological documentation of this condition, is presented. (Acta Med Colomb 2019; 44. DOI:https://doi.org/10.36104/amc.2019.1203).

ABSTRACT As the correct measurement is an essential part of water management, this study describes the metrological behaviour of a range of bulk water meters under different installation configurations. The meters analysed included the horizontal and vertical Woltman, singlejet, tangential and proportional. Configurations included straight pipe lengths; gate and butterfly valves at different degrees of closure, rotations and distances from the meter; meter with volumetric and reducing valves; reverse installation; and meter rotated 90° from the horizontal setting. The metrological behaviour under different flow conditions was analysed by comparison with electromagnetic and volumetric meters (ISO-4064). The horizontal Woltman showed no permissible errors with reverse installation; gate valve closed 75% and placed alongside the meter; and with butterfly valve closed 30°, non-rotated, and rotated right or left. The vertical Woltman gave no permissible errors with reverse installation. The single-jet meter did not show any errors above the permitted limit. The tangential meter had no permissible errors with reverse installation and in almost all configurations with gate and butterfly valves. The proportional meter showed no permissible errors with a gate valve at any degree of closure.

ABSTRACT Venturi-type chemigation injectors are widely used due to their advantages: they do not require electric power and are cheap to operate. However, they also generate considerable energy losses which affect the pressure in the system. The correct characterization of these systems requires pressures to be correctly set at the inlet, injector and outlet points in relation to main and injected solution flows. These analytical relationships, as described in the International Organization for Standardization’s standard ISO 15873:2002, can be obtained theoretically, although it is recommended that the manufacturer should determine the real behavior of the injector by operational tests. These relationships should also be provided graphically in the form of nomograms in order to facilitate the association of the variables involved and the subsequent selection of a specific model or class and type of assembly. In order to make the right choice, it is also necessary to have precise information on the irrigation sub-units that it feeds and the grower’s fertilization program.

RESUMEN El inyector para quimigación tipo Venturi tiene ventajas que hacen que sea un dispositivo bastante utilizado; no requiere energía eléctrica y es económico. Por el contrario, genera pérdidas de energía elevadas, afectando a las presiones en la instalación. Para una correcta caracterización de estos equipos deben relacionarse las presiones en los puntos de entrada, salida e inyección con los caudales principales e inyectados. Estas relaciones analíticas, que las introduce la norma de la Organización Internacional de Normalización (ISO 15873:2002), se pueden obtener de forma teórica; aunque es más recomendable que el fabricante establezca mediante ensayos de funcionamiento, el comportamiento real del inyector. Es oportuno que estas relaciones se proporcionen gráficamente, en la forma de nomogramas, para facilitar la asociación de las variables implicadas y la posterior selección de un modelo o clase concretos bajo una tipología de montaje. Así, para que esta selección sea adecuada es necesario también el conocimiento preciso de las subunidades de riego que alimenta y el programa de fertilización de la explotación.

Resumo Para manter a qualidade de medição do consumo de água, é necessário conhecer a metrologia de hidrômetros unijato ao longo do tempo. Conhecer a metrologia desses instrumentos com o tempo permite estabelecer um período de operação metrológica para diferentes vazões. Isso ajudará as empresas de água a otimizar a gestão e a reduzir as perdas econômicas devido ao consumo do volume de água não contabilizado. Neste estudo, a influência do fator tempo sobre o erro de medição de hidrômetros unijato foi analisada com o objetivo de estimar sua deterioração e, com isso, o período de operação metrológica. Conforme as normas 8316 e 4064 da Organização Internacional de Normalização (ISO), foram avaliados em seis abastecimentos 808 hidrômetros de classe metrológica B, com uma faixa de idade de 3,7 a 16,4 anos de uso. O erro de medição foi calculado pela comparação entre o volume de um depósito calibrado e o volume medido pelos hidrômetros, nas vazões de 30, 120, 750 e 1.500 L h-1. O período de operação metrológica dos medidores foi estimado para cada vazão, por meio da relação entre erro de medição e tempo de uso (regressão linear simples). De acordo com os resultados, a maioria dos hidrômetros apresenta erros crescentes de submedição com o tempo, sendo mais pronunciados nas vazões reduzidas e nas condições de funcionamento menos favoráveis. O período de operação metrológica para as vazões de 30, 120, 750 e 1.500 L h-1 é estimado em aproximadamente 3, 8, 14 y 13 anos. Este período de operação, combinado com os padrões de consumo dos usuários, estabelecerá o melhor momento para substituir os hidrômetros.

Abstract To maintain quality measurement of water consumption, it is necessary to know the metrology of single-jet water meters over time. Knowing the accuracy of these instruments over time allows establishing a metrological operation period for different flow rates. This will aid water companies to optimize management and reduce economic losses due to unaccounted water consumption. This study analyzed the influence of time on the measurement error of single-jet water meters to evaluate the deterioration of the equipment and, with that, launch the metrological operation period. According to standards 8316 and 4064 of the International Organization for Standardization (ISO), 808 meters of metrological Class B were evaluated in six water supplies, with age ranges of 3.7 to 16.4 years of use. The measurement error was estimated by comparing the volume measured in a calibrated tank with the volume registered by the meters at flow rates of 30, 120, 750 and 1,500 L h-1. The metrological operation period of the meters was obtained for each flow rate by the relation between error of measurement and time of use (simple linear regression). According to the results, the majority of the equipment presents increasing under-registration errors over time, more pronounced at low flow rates and with less favorable operating conditions. The metrological operation period for flow rates of 30, 120, 750 and 1,500 L h-1 is estimated at approximately 3, 8, 14 and 13 years. This operation period combined with consumption patterns of users will establish the best time to replace the meters.

RESUMEN El artículo trata de abordar algunos aspectos de articulación entre pluralismo y justicia. Más concretamente, las posibilidades de profundizar en una teoría de la justicia que sea capaz de acoger en un mismo marco político a ciudadanos de culturas y valores heterogéneos. Ello conduce a destacar algunas de las deficiencias de posturas relativistas y monistas y a defender una posición que parta de la posición del liberalismo político y la supere con el fin de conducir a un marco político ni neutral ni perfeccionista.

ABSTRACT The article seeks to address some aspects of the articulation between pluralism and justice. More specifically, the possibilities to delve into a theory of justice that is able to host within the same political framework citizens from heterogeneous cultures and values. This leads to highlight some of the shortcomings of the relativistic and monistic positions and to defend a position that starts from the position of political liberalism and goes beyond it, in order to lead to a political framework neither neutral nor perfectionist.

ABSTRACT To determine the influence of geometry on the hydrodynamic behavior of Venturi injectors, using computational fluid dynamics techniques, we studied, at the Universitat Politècnica de València, Valencia, Spain, the geometric parameters that exert the most influence on head losses: the relationship between throat diameter and nozzle (β), nozzle angle (α1) and diffuser angle (α2). In addition, three throat morphologies (B1: nozzle-throat and throat-diffuser with a sharp edge; B2: nozzle-diffuser with a zero-length, sharp-edge throat; B3: nozzle-throat and throat-diffuser with rounded edge). We analyzed their influence on the velocity distribution and differential pressure between inlet and throat (DP/γ), throat and outlet (Δhv/γ), and outlet and throat ((P3-P2)/γ). The development of the velocity profile from the throat is slower the greater β is and the lower α2 is. DP/γ decreases with β, increases with α1 and varies little with α2. Δhv/γ decreases with β and increases with α1 and α2. (P3-P2)/γ decreases with β and increases with α1 and α2. Geometry B3 decreases the losses and delays the onset of cavitation. Thus, the lower β and the higher α2, the greater the losses; however, the influence of α1 is less clear. The rounded edges produce lower head losses.

RESUMEN Para determinar la influencia de la geometría en el comportamiento hidrodinámico de inyectores Venturi, mediante técnicas de dinámica de fluidos computacional, se estudió, en la Universitat Politècnica de València, Valencia, España, los parámetros geométricos que más influencian las pérdidas de carga: relación entre diámetro de la garganta y tobera (β), ángulo de la tobera (α1) y ángulo del difusor (α2). Además, tres morfologías de la garganta (B1: tobera-garganta y garganta-difusor en arista viva; B2: tobera-difusor con garganta de longitud nula y en arista viva; B3: tobera-garganta y garganta-difusor en arista redondeadas). Se ha analizado su influencia en la distribución de velocidad y en la presión diferencial entre entrada y garganta (DP/γ), garganta y salida (∆hv/γ), y salida y garganta ((P3-P2)/γ). El desarrollo del perfil de velocidades a partir de la garganta es más lento cuanto mayor es β y menor es α2. DP/γ disminuye con β, aumenta con α1 y es poco variable con α2. ∆hv/γ disminuye con β y aumenta con α1 y α2. (P3-P2)/γ disminuye con β y α1, yaumenta con y α2. La geometría B3 disminuye las pérdidas y retarda la aparición de la cavitación. Así, cuanto menor es β y cuanto mayor es α2, mayores son las pérdidas de carga, sin embargo, la influencia de α1 no es tan clara. Las aristas redondeadas producen menores perdidas de carga.

RESUMOPara aperfeiçoar o manejo fitossanitário de pragas na cultura do melão (Cucumis melo L.), objetivou-se avaliar os efeitos de formas de aplicação e doses de inseticidas sobre a eficiência de controle químico do pulgão A. gossypii. O experimento foi realizado em 2010, na cidade de Fortaleza, Ceará, com melão amarelo cultivado em condições de campo. O delineamento experimental foi em blocos ao acaso, arranjo fatorial 2 x 4, com quatro repetições e parcelas de seis plantas. Os tratamentos foram duas formas de aplicação (pulverização costal manual e insetigação por gotejamento) e quatro doses de inseticida (0; 50; 100; 200% da dose recomendada pelo fabricante). Os inseticidas acefato e tiametoxam, testados separadamente, foram aplicados em manejo de rotação de grupos químicos. A eficiência de controle foi avaliada sete dias após o uso de cada inseticida. O acefato não apresentou diferença significativa entre as formas de aplicação, atingindo eficiências de controle de 88,95 e 84,09% com 100 e 200% da dose recomendada, respectivamente. O tiametoxam não diferiu significativamente quanto às formas de aplicação e doses testadas, apresentando eficiência de 100% em todos os tratamentos. Atualmente, no Brasil, a utilização de acefato no melão está limitada à aplicação mecanizada devido ao risco de contaminação. Diante dessa limitação, o controle do pulgão em meloeiro amarelo pode ser realizado via insetigação por gotejo ou pulverização costal manual, devendo-se empregar, preferencialmente, 100% da dose recomendada de tiametoxam.

ABSTRACTIn order to perfect the phytosanitary management of pests in the melon crop (Cucumis melo L.), the aim here was to evaluate the effects of different methods of application and dosages of insecticides on the effectiveness of chemical control of the aphid A. gossypii. The experiment was carried out in 2010, in Fortaleza, in the state of Ceará, Brazil, with yellow melon grown under field conditions. The experimental design was of randomised blocks in a 2 x 4 factorial arrangement, with four replications and lots of six plants. Treatments consisted of two methods of application (manual backpack spray and drip insectigation) and four dosages of insecticide (0, 50, 100 and 200% of the dosage recommended by the manufacturer). The insecticides acephate and thiamethoxam, tested separately, were applied in a rotating management of chemical groups. Efficiency of the control was evaluated seven days after the use of each insecticide. The acephate showed no significant difference between the forms of application, reaching control efficiencies of 88.95 and 84.09% with 100 and 200% of the recommended dose respectively. The thiamethoxam did not differ significantly for the application methods and dosages under test, giving 100% efficiency in all treatments. Currently in Brazil the use of acephate in the melon is limited to mechanised application due to the risk of contamination. Because of this limitation, the control of aphids in yellow melon can be carried out via drip insectigation or backsack spray, with preferably 100% of the recommended dose of thiamethoxam.

The performance and installation alternatives of four Venturi injector prototypes were studied at Universitat Politècnica de València, Valencia, Spain (39°29' N; 0°23' W; 20 m). This device performance was studied under several parameters such as head loss, relation of flows and injection efficiency. The installation configurations analyzed were: without the injection of nutrients solution and with the injection either having negative or positive pressure at the Venturi throat. The inlet pressures were established between 10 and 40 m.w.c. The experimental data has been processed using multiple stepwise regression techniques and analysis of variance (ANOVA). Moreover, geometry integration versus diameters, flows and pressures is used to obtain some equations for predicting the head loss and injected flow. The results of the present study showed that the relation between flows and injection efficiency were better when the diameter of inlet nutrient line increases and become worse when decreases the diameter of the Venturi throat. Accordingly, these dimensions become very important in the design prototype and installation configuration. Furthermore, after the analysis of laboratory experiments it can be concluded that head losses, at the same injected flow, were lower if the injection was carried out with positive pressures at the throat than in the case of negative pressures. Also in this case, the relationship between flow rates and injection efficiency leaded to a good performance of the proposed installation.

En la UniversitatPolitécnica de València, Valencia, Espana (39°29' N; 0°23' W; 20 m), ha sido estudiado el funcionamiento de cuatro prototipos de inyector Venturi y tres formas de instalación distintas. El funcionamiento se ha analizado bajo diversos parâmetros, como pérdidas de carga, relación de caudales y rendimiento. Las formas de instalación analizadas han sido: sin inyección y con inyección y presiones negativas o positivas en la garganta. Las presiones se establecieron entre 10 y 40 m.c.a. A partir de los datos experimentales han sido procesados utilizando técnicas de regresión múltiple y análisis de la varianza. Con ellas, fue posible, a través de la integración de geometrías en función de los diâmetros, caudales y presiones, obtener expresiones para prever la pérdida de carga o el caudal inyectado. Se pone de manifiesto que la relación de caudales y el rendimiento son mayores cuanto mayor es el diámetro de la aspiración y empeoran al reducirse el diámetro de la garganta, siendo estas las dimensiones que más condicionan la inyección. También, puede afirmarse que la pérdida de carga, para un mismo caudal inyectado, es inferior si la operación se realiza con presiones positivas que con presiones negativas. La relación de caudales o el rendimiento también proporcionan valores más elevados bajo esta forma de instalación propuesta.

The design and prediction performance of four Venturi injector prototypes have been studied using Computational Fluid Dynamics (CFD) techniques. Results were compared with experimental tests carried out in the laboratory of the Universitat Politècnica de València, Valencia, Spain. The analysed and selected geometries for each prototype were used to simulate the operation without nutrient injection (G1) and with nutrient injection (G2). In first case (G1), the results were presented in the form of pressure profile at the injector axe under different velocities and the pressure distribution in the whole geometry. Additionally, this paper analysed the evolution of pressures and head loss versus main water flow in the different prototypes. The relative error was estimated to compare CFD and experimental results. The second case (G2), the graphical representation for the relations between the nutrient aspiration flow and water main flow were obtained for numerical and experiment approaches. In conclusion, CFD techniques appear as a suitable tool for the analysis of the Venturi injector operation, but its validation with experimental data is recommended.

En la Universitat Politècnica de València, Valencia, España, se ha estudiado el diseño y funcionamiento de cuatro prototipos del inyector Venturi con técnicas de Dinámica de Fluidos Computacional (CFD), comparándo las con ensayos en laboratorio. Para cada prototipo, las geometrías definidas y analizadas han permitido simular el funcionamiento sin (G1) y con inyección (G2) para quimigación. En el caso G1, se presentan los gráficos del perfil de presiones en el eje del inyector para diversas velocidades, así como la distribución del campo de presiones y de la evolución de las diferencias de presión y pérdidas de carga frente al caudal principal. Para comparar los resultados obtenidos con CFD frente al resultado experimental, se calculó el error relativo. En el caso G2, se obtuvo la representación gráfica del el caudal de inyección frente al caudal principal. Las técnicas CFD exigen un buen ajuste del modelo para dar un resultado aceptable. Son interesantes para comparar geometrías, analizar sus variantes, realizar prediseños y aproximar ordenes de magnitud, pero es recomendable su ensayo en laboratorio para validar los resultados.

Objetivando fornecer subsídios para os produtores aperfeiçoarem o manejo da fertirrigação em pequenas áreas, avaliou-se, na Universitat Politècnica de València, Valência, Espanha (39º 29′ N, 0º 23′ W, 20 m), a uniformidade de distribuição do K2O via irrigação por gotejamento superficial em função da distância do ponto de injeção na linha principal. A irrigação foi efetuada por linhas laterais com emissores não compensantes, espaçados de 0,3 m. Na fertirrigação, foi utilizada uma bomba injetora de fertilizante de acionamento elétrico, com o tempo de injeção de 0,25 h. O delineamento experimental foi o de blocos casualizados, com cinco tratamentos e quatro repetições. Os tratamentos consistiram em cinco pontos de injeção na linha principal, situados a: 10; 20; 30; 40 e 50 m da primeira linha lateral. Foram coletadas amostras em emissores localizados no início, a 1/3, a 2/3 e no final das linhas laterais. A concentração do nutriente foi determinada por espectrofotometria de chama. Foram estimados os coeficientes de uniformidade de Christiansen (CUC), de distribuição (CUD), estatístico (CUE) e de emissão (CUe). A concentração e a distribuição de K2O diminuíram linearmente com o aumento da distância do ponto de injeção. Em todos os tratamentos, o CUC, CUE e CUD foram classificados como 'excelente'. O CUe foi classificado como 'recomendado' apenas na menor distância de injeção.

The purpose of this research was to evaluate the K2O distribution uniformity by surface drip irrigation at Universitat Politecnica de Valencia, Valencia, Spain (39º 29′ N, 0º 23′ W, 20 m). The irrigation was performed by drip lines with not-compensated emitters, spaced 0.3 m. The fertigation was realized using a fertilizer injector pump of electric action with injection of 0.25 h. The experimental design used completely randomized blocks with five treatments and four replications. The treatments consisted of injection in five distances, located at 10; 20; 30; 40; 50 m of the first drip line. Samples were collected in emitters located at the start, at 1/3, at 2/3 and at the end of the drip lines. The nutrient concentration was determined by flame spectrophotometry. The Christiansen's uniformity coefficients (CUC), of distribution (DUC), of statistical (SUC) and of emission (eUC) were estimated. The K2O concentration and distribution decreased linearly with the increase of the injection distance. In all treatments, the CUC, SUC and DUC were described as 'excellent'. The eUC was described as 'recommended' only at smaller injection distances.