Hydraulic Performance Analysis of Drip Irrigation System Using Pressure Compensated Dripper at Low Operating Pressure

Irrigation is the most important component in ensuring that crops can produce optimal yields. The use of drip irrigation can help farmers in providing water to crops in the amount required by the crop. Drip irrigation usually uses an uncompensated dripper and also a pressure compensated dripper. The use of an uncompensated dripper requires precise pressure to ensure a uniform flow for each dripper while the use of a pressure compensated dripper will also provide a uniform flow when operating pressure was used within the range specified by the dripper manufacturer. The purpose of this study is to evaluate the hydraulic performance of the drip irrigation system using low pressure compared to the minimum pressure recommended by dripper manufacturers. The pressure operation recommended by the manufacturer is 1.5-4 bars. This study uses pressures as low as 1 bar (low pressure), 2 bars, and 2.5 bars (recommended by manufacture) to operate this irrigation system. The volumetric approach was used to calculate each emitter's flow rate. Coefficient uniformity (CU), emission uniformity (EU), coefficient of variation (CV), and emitter flow variation (EFV) were the hydraulic parameters evaluated. The results show that CU, CV, and EU are in excellent classification, and the value for CU and the EU is more than 95 percent efficiency. The CV value is below 0.03 which is a very good classification. Meanwhile, emitter flow variation is 10% when operating at 2.5 bars and 2.0 bars and is considered the desirable classification. On the other hand, the emitter flow variation was reported at 6% for the 1 bar operating pressure and the classification was also recorded in the desirable classification. The results conclude that the use of low operating pressure compared to the minimum operating pressure proposed by the manufacturer can also operate in excellent condition according to the hydraulic parameters evaluated.

Public sector communication professions in the Twitter-sphere

The paper aims to critically analyze the debate on Public Sector Communication professions that has developed on Twitter with regard to its content and to the main actors involved. We focus on the themes and the words used, in order to explore how discourses about the reform are framed. Secondly, we aim at understanding whether and how different actors have appropriated the topic. While the core of our study adopts qualitative methods, we also provide basic quantitative metrics, which contribute to a better understanding of the dynamics characterizing the conversations addressing public sector communication (PSC). Quantitative analyses include activity metrics, patterns of influence, tweet flow variation over time, user activity, tweet popularity. We then perform a thematic analysis, aiming at identifying the pre-vailing issues, the goals, and the communication style adopted.

Impact of Flow Variation on Hydropower Projects in Budhigandaki River Basin of Nepal

Daily flow data from 1964 to 2015 of Budhigandaki River at Arughat were analyzed to assess the impact of flow variation at different time scales to the run of the river (RoR) type of hydropower projects. The data show very high inter-annual variation in daily, monthly and seasonal flows. The long term annual average flow at Arughat was 160 m3/s and varies from 120 to 210 m3/s. The long-term averages of loss in flow for both dry and wet seasons based on daily flows for three design discharges (Q90, Q60 and Q40) were found to be respectively -0.72, -1.76 and -1.54 m3/s for dry season and 0.0, -0.27 and -2.26 m3/s for wet season. Although long-term average loss is small, uncertainty increases with the increase in design discharge. The long-term dry season power loss is about 3 % for the RoR projects of the basin however, its annual variation is large. There is a probability of losing the quantum of energy generation by nearly 40% in some years and gaining by about 30 % in some other years in dry season. The impact of flow variation on power production was negative in both dry and wet seasons for RoR projects of Budhigandaki basin. This study concludes that uncertainty arising from daily flow variation should be assessed while estimating energy generation in hydropower projects. Intra-annual flow variation is, thus, to be taken into consideration while calculating the power generated by the RoR plants; and it should be reflected in power purchase agreement.

Performance Assessment of Drip System of Irrigation used for Cultivating Tomato in Premises of the Centre of Excellence Protected Cultivation, Raipur, Chhattisgarh, India

A technical report was conducted for checking performance assessment of drip irrigation system which was used for cultivating tomato in premises of the Centre of Excellence Protected Cultivation, Raipur (Chhattisgarh). A uniformity coefficient was found for drip irrigation system which ranges from 73.2 % to 83.6%. The coefficient of variance varies between 0.0055 to 0.0068 for the measured discharges of four laterals laid in the field. It shows that there is the least variation between the obtained flow rates of different laterals under study. The application efficiency of four different lateral lines operating at a pressure of 1.25 kg/cm2 was calculated and it found to be more than 90.00 %, excluding lateral line (L2). Almost same amount of flow variation (8-9%) is found in lateral lines L1, L3 and L4, although Lateral line (L2) discharges 11.00 % more water among others. The maximum flow variation was found for the lateral line (L3) and the least flow variation was for the lateral line (L1). The distribution efficiency of all the laterals was found more than 97.45 %.

Dynamic visceral ischaemia in type A dissection

We describe a case of dynamic obstruction of the mesenteric arteries caused by aortic dissection. The flow pattern demonstrates a periodic flow variation, during which peak systolic velocity varied fourfold.

COMPARAÇÃO ENTRE METODOLOGIAS PARA DIMENSIONAMENTO DE LINHAS LATERAIS PAREADAS DE GOTEJAMENTO EM DESNÍVEL

COMPARAÇÃO ENTRE METODOLOGIAS PARA DIMENSIONAMENTO DE LINHAS LATERAIS PAREADAS DE GOTEJAMENTO EM DESNÍVEL ÍCARO MONTEIRO GALVÃO1; JOÃO DE JESUS GUIMARÃES2; ALBERTO MARIO ARROYO AVILEZ3 E JOÃO CARLOS CURY SAAD4 [1] Departamento de Engenharia de Biossistemas, ESALQ/USP, Av. Pádua Dias, São Judas, CEP 13418-900, Piracicaba, SP, Brasil. e-mail: [email protected] 2 Departamento de Engenharia Rural e Socioeconomia, FCA/UNESP, Av. Universitária 3780, Altos do Paraíso, CEP 18610-034, Botucatu, SP, Brasil. e-mail: [email protected] 3 Departamento de Engenharia Rural e Socioeconomia, FCA/UNESP, Av. Universitária 3780, Altos do Paraíso, CEP 18610-034, Botucatu, SP, Brasil. e-mail: [email protected] 4 Prof. Titular, Departamento de Engenharia Rural e Socioeconomia, FCA/UNESP, Av. Universitária 3780, Altos do Paraíso, CEP 18610-034, Botucatu, SP, Brasil. e-mail: [email protected] 1 RESUMO O objetivo deste trabalho foi comparar diferentes metodologias para a determinação dos trechos em aclive e em declive de linhas laterais pareadas em terreno com desnível uniforme, para um sistema de irrigação por gotejamento. Para tal utilizou-se as metodologias propostas por Keller e Bliesner (1990), Jiang e Kang (2010) e Monserrat; Barragan e Cots (2018). Calculou-se o comprimento das linhas em aclive e declive, o coeficiente de uniformidade de distribuição (CUD) e as variações de vazão e de pressão para ambas as condições topográficas. A metodologia de Keller e Bliesner (1990) foi a que melhor dimensionou as linhas pareadas, com menor diferença de desempenho entre os trechos em aclive e declive, em termos de CUD e de variação de vazão e de pressão, além de permanecer dentro do limite máximo de variação de vazão de 10%. O segundo melhor desempenho foi obtido pelo método de Monserrat; Barragan e Cots (2018). O procedimento de Jiang e Kang (2010) foi o menos adequado, tendo gerado no trecho em aclive variação de vazão de 10,9%. Palavras-chave: gotejamento, linha lateral, comprimento, declividade. GALVÃO, I. M.; GUIMARÃES, J. J.; AVILEZ, A. M. A.; SAAD, J. C. C. METHODOLOGIES COMPARISON FOR DESIGN OF PAIRED DRIP LATERALS ON UNIFORMLY SLOPING FIELDS 2 ABSTRACT This work aimed to compare different methodologies for designing paired laterals of drip irrigation systems on uniformly sloping fields. For this purpose, the methodologies proposed by Keller e Bliesner (1990), Jiang e Kang (2010), and Monserrat; Barragan e Cots (2018) were evaluated. The length of uphill and downhill lateral lines, distribution uniformity (DU), flow, and pressure variations were calculated for both topographic conditions. The Keller e Bliesner (1990) methodology generated the best design for paired laterals, with the lowest DU difference between the uphill and downhill sections; also, the flow variation remained under the 10% limit. The second-best performance was obtained by the method of Monserrat; Barragan e Cots (2018). Jiang e Kang (2010)’s procedure was the least adequate, generating a 10.9% flow variation in the uphill section. Keywords: drip irrigation, hydraulic, uniformity.