• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 10
  • 8
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 29
  • 29
  • 12
  • 7
  • 5
  • 5
  • 5
  • 4
  • 4
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Hydraulic analysis of trickle lateral

Soom, Mohd Amin Mohd January 1989 (has links)
No description available.
2

Evaluation of a Potential Site for a Small Hydropower Plant Located in the BioBio North Irrigation System, Chile

Gunnar, Sofie January 2010 (has links)
<p>This project considers an evaluation of a potential site for a small hydropower plant located in the BioBio north irrigation system, Chile. The purpose was to analyze the potential and constraints in harnessing the energy of an existing infrastructure of irrigation canals for electrical production. The site was analyzed technically, economically and managerially. Before this project nothing was done and therefore the investigations are a main part of the project. A preliminary design for the plant was proposed and the project was named the Minicentral Quillaileo-Mininco.</p><p>Investigations showed a flow variation of 1.62-2.2 m<sup>3</sup> per second and a gross head of 44.3 meters. Evaluation gave a possible capacity of 840 kW producing 5 800 MWh annually. Appropriate electromechanical equipment is a Francis turbine with a diameter of 0.5 meter directly coupled to a 1000 rpm synchronous generator. The penstock recommended is a DN 1200 Flowtite GRP. The station is to be fully automatic and connected to the national grid.</p><p>The revenue is based on analysis of the past three year’s electrical market. The costs are based on budget proposals, statistical values and local comparisons. The economical analysis, based on a discount rate of 12% and life span of 35 years, gives a positive cash flow within eight years and a simple payback period of 5 years. The project will have a NPV value of 444 900 USD, IRR 14.70% and B/C of 1.2. Cost per kW will be 2 980 USD. The project is recommended to be further developed.</p>
3

Evaluation of a Potential Site for a Small Hydropower Plant Located in the BioBio North Irrigation System, Chile

Gunnar, Sofie January 2010 (has links)
This project considers an evaluation of a potential site for a small hydropower plant located in the BioBio north irrigation system, Chile. The purpose was to analyze the potential and constraints in harnessing the energy of an existing infrastructure of irrigation canals for electrical production. The site was analyzed technically, economically and managerially. Before this project nothing was done and therefore the investigations are a main part of the project. A preliminary design for the plant was proposed and the project was named the Minicentral Quillaileo-Mininco. Investigations showed a flow variation of 1.62-2.2 m3 per second and a gross head of 44.3 meters. Evaluation gave a possible capacity of 840 kW producing 5 800 MWh annually. Appropriate electromechanical equipment is a Francis turbine with a diameter of 0.5 meter directly coupled to a 1000 rpm synchronous generator. The penstock recommended is a DN 1200 Flowtite GRP. The station is to be fully automatic and connected to the national grid. The revenue is based on analysis of the past three year’s electrical market. The costs are based on budget proposals, statistical values and local comparisons. The economical analysis, based on a discount rate of 12% and life span of 35 years, gives a positive cash flow within eight years and a simple payback period of 5 years. The project will have a NPV value of 444 900 USD, IRR 14.70% and B/C of 1.2. Cost per kW will be 2 980 USD. The project is recommended to be further developed.
4

Řízení pohonu kalového čerpadla přes GSM / Control of pump over GSM

Rybár, Vladimír January 2019 (has links)
The topic of the final thesis is the project and realization of the pump control using GSM. The present (actual, current) state of control unit of irrigation system is analyzed in the introduction of this thesis. The core of this thesis is to design new controlling irrigation system with using GSM control. In this thesis there are selected suitable (appropiate) components, which are meeting the assigment. After that, the control program was designed. The conclusion of the thesis is to verify the functionality of designed system, to summarize achieved the result and to summarize the possibilities of the system expansion options.
5

A Methodology to Conduct Diagnostic Performance Assessment and Simulation of Deliveries in Large-Scale Pressurized Irrigation Systems

Zaccaria, Daniele S.A. 01 May 2011 (has links)
A methodology was developed to conduct diagnostic performance assessment and simulation of alternative delivery scenarios in pressurized irrigation distribution networks. It consists of three components, an agro-hydrologic model able to forecast peak water demand hydrographs, a hydraulic model with capability of simulating the network behavior under different flow configurations, and a set of performance indicators for conducting assessments of performance achievements relative to specified targets. As a preliminary work, the current delivery schedule of an existing pressurized irrigation network (system 1) and the resulting effects on crop irrigation management were analyzed by simulating soil water balance and irrigation scheduling at field level. Simulations allowed analyzing the on-farm irrigation management under the current rotation deliveries, and comparing it with an alternative flexible irrigation scheduling to maximize crop yields. Results at field level were up-scaled to the entire command area of the system, showing the usefulness of soil water balance and of irrigation scheduling as analytical tools to demonstrate the inconsistency between the current water delivery and crops’ and farmers’ requirements. This preliminary work also allowed highlighting the need for modernizing the irrigation management in the first of the two study areas considered for the present research work (system 1 located in the province of Taranto, southern Italy). An existing agro-hydrological model conceived to forecast water demand hydrographs in pressurized delivery networks was enhanced through several refinements and amendments of the computation algorithms. The refined model was applied for validation at different management levels on an existing pressurized irrigation system (system 2) located in the province of Foggia, southern Italy, where water withdrawals by farmers and the main hydraulic parameters are recorded on a continuous basis for monitoring purposes. Results from validation showed that the model is capable of forecasting with good accuracy the timing of peak-demand periods, the seasonal demand irrigation volumes, as well as the hydrographs of hourly flow rates demanded by farmers during these peak periods, especially when it is applied to large multi-cropped command areas. Performance indicators, originally conceived for diagnostic assessment in canal systems, were modified for application to pressurized distribution networks, and reference standard values were proposed. These indicators were then applied for validation to the second study area (irrigation system 2), where records of water deliveries are available, and showed their usefulness for diagnostic performance assessments.
6

Utiliza??o de acionador simplificado de baixo custo para manejo de irriga??o de mudas de Aroeira - Pimenteira (Schinus terebinthifolius) / Use of simplified low cost driver for irrigation management of Aroeira - Pimenteira (Schinus terebinthifolius) seedlings

OLIVEIRA JUNIOR, Angelo Gomes de 31 August 2016 (has links)
Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2017-07-12T18:54:47Z No. of bitstreams: 1 2016 - Angelo Gomes de Oliveira Junior.pdf: 1739096 bytes, checksum: 0add068fbe6a3c053e8c653b8b2f1829 (MD5) / Made available in DSpace on 2017-07-12T18:54:47Z (GMT). No. of bitstreams: 1 2016 - Angelo Gomes de Oliveira Junior.pdf: 1739096 bytes, checksum: 0add068fbe6a3c053e8c653b8b2f1829 (MD5) Previous issue date: 2016-08-31 / The aim of this research was study the use of simplified irrigation controller (SIC) in 4 tensions values to determine the best tension for the development of seedlings of Schinus terebinthifolius in protected environment. The treatments were: T 1 = 4 kPa of tension, T 2 = 6 kPa of tension, T 3 = 8 kPa of tension and T 4 = 10 kPa of tension. The seedlings were grown in plastic bags with 3534 cm3 of a volume. The parameters evaluated were diameter at breast height (D), height (H), relation H / D, dried mass weight of roots (DMWR), dried mass of aerial part (DMAP), Dickson quality index (DQI), water use efficiency (WUE) and chlorophyll content (IFC). The evaluations were performed every two weeks, from 30 days after transplanting up to 105 days. The results indicated that the 6 kPa of tension consists in optimum operating value for the system proposed in terms of experimental conditions studied because it represents the best growth ratio by volume of water used for irrigation. In this treatment the average results per plant were: D= 5.61 mm; H= 33.20 cm; H / D= 5.97; DMAP= 4.78 g; DMWR= 2.44 g; DQI= 0.91; WUE= 1.53 and IFC= 56.55. It's not recommended the production of seedlings of Schinus terebinthifolius using 10 kPa of tension because there was a high mortality. / O objetivo deste trabalho foi avaliar a utiliza??o do acionador simplificado de irriga??o (ASI) em 4 (quatro) diferentes tens?es de ?gua no substrato para determinar a melhor tens?o para o desenvolvimento das mudas de Aroeira-Pimenteira (Schinus terebinthifolius) em ambiente protegido. Os tratamentos utilizados foram: T 1 = Tens?o de 4 kPa, T 2 = Tens?o de 6 kPa, T 3 = Tens?o de 8 kPa e T 4= Tens?o de 10 kPa. As mudas foram produzidas em sacos pl?sticos com volume de 3.534 cm3. Os par?metros avaliados foram di?metro de colo (D), altura (H), rela??o altura por di?metro de colo (H/D), fitomassa seca das ra?zes (MSR), fitomassa seca parte a?rea (MSPA), ?ndice de qualidade de Dickson (IQD), efici?ncia de uso de ?gua (EUA) e clorofila total (IFC). As avalia??es foram realizadas quinzenalmente, a partir dos 30 dias ap?s o transplante at? os 105 dias. Os resultados obtidos indicaram que a tens?o de 6 kPa compreende a tens?o ?tima de opera??o para o sistema proposto diante das condi??es experimentais estudadas e isso deve-se a melhor rela??o crescimento por volume de ?gua utilizado na irriga??o. Neste tratamento os resultados m?dios por planta foram: D= 5,61 mm; H= 33,20 cm; H/D= 5,97; MSPA= 4,78 g, MSR= 2,44 g; IQD= 0,91; EUA= 1,53 g L-1 e IFC= 56,55. N?o se recomenda a produ??o de mudas de aroeira utilizando uma tens?o de 10 kPa pois houve uma alta taxa de mortalidade das mudas.
7

Propuesta de un modelo básico basado en la gestión por procesos enfocado en el mantenimiento de la producción de uvas para el aumento de la productividad en las Mypes de la región de Ica / Proposal for a basic model based on process management focused on the maintenance of the production of grapes to increase productivity in the mypes of the ica region

Becerra Tello, César Ivan 06 September 2020 (has links)
El presente trabajo de investigación es el resultado del trabajo continuo y perseverante en el estudio de la producción de uvas de mesa en la región de Ica. Para ello, se focalizó el estudio en las mypes, ya que uno de los objetivos de este trabajo es contribuir con el conocimiento adquirido para organizar estas empresas. Por esta razón, se utilizó la gestión por procesos para ordenar la empresa desde el punto de vista del valor agregado que le podemos ofrecer al cliente. Este trabajo está enfocado en el proceso de mantenimiento en producción, cuyo principal objetivo es mitigar todos aquellos factores que impidan el crecimiento de la uva de mesa. Es decir, tomando como base el mantenimiento autónomo, se proponen actividades de mantenimiento para tener en óptimas condiciones el terreno de cultivo, el sistema de irrigación y la estructura del parral. Esto permitirá que la uva pueda tener las características físicas necesarias para la venta a grandes acopiadores. Cabe resaltar que este es el medio por el cual los agricultores pueden adquirir mayor margen de ganancia. Finalmente, todas las propuestas en esta tesis han sido realizadas para las personas que administran estas mypes. En su mayoría, son personas con estudios secundarios y no cuentan con especializaciones para poder dirigir sus empresas. / The present research work is the result of continuous and persevering work in the study of grape production in the Ica region. For this, the study was focused on the mypes, since one of the objectives of this work is to contribute with the knowledge acquired to organize these companies. For this reason, process management was used to order the company from the point of view of the added value that we can offer to the client. This work is focused on the maintenance process in production, whose main objective is to mitigate all those factors that impede the growth of grapes. Based on autonomous maintenance, related maintenance activities were proposed to keep the cultivation land, the irrigation system and the structure of the vine in optimal conditions. This will allow the grape to have the physical characteristics necessary for sale to large collectors. It should be noted that this is the means by which farmers can acquire a higher profit margin. Finally, all the proposals in this thesis have been made for the people who administer these mypes. For the most part, they are people with secondary education and do not have specializations to be able to run their companies. / Tesis
8

Automatic irrigation system for plants / Automatiserat bevattningssytem för plantor

Hermansson, Hanna, Lundblad, Louise January 2019 (has links)
The purpose of this project was to develop an automatic irrigation system for plants. It is beneficial to have plants indoors. In addition to their air-purifying qualities, they have been proven to increase the productivity of employees at workplaces, as well as decrease the amount of sick leave. Three research question were investigated: how much energy the system requires and if it is possible to replace the energy source with an alternative energy source, how well the system stabilises and how a wireless regulation can be implemented. The final design consisted of a mictrocontroller which controlled the system, a water pump, a moisture level sensor and a plant on which everything was tested. The system was left during a four week period to see how well it managed. The project resulted in a system that managed to keep the plant alive. The energy demand of the system could be covered by solar cells instead of batteries. / Syftet med detta projekt var att utveckla ett automatiskt bevattningssystem för växter. Det är fördelaktigt att ha växter inomhus. Bland annat har det bevisats att växter i kontorslandskap ökar produktiviteten hos de personer som arbetar där, samt att antalet uttagna sjukdagar minskar. Fortsättningsvis var det tre stycken forskningsfrågor som undersöktes, hur mycket energi kräver systemet och är det möjligt att ersätta energikällan med en alternativ energikälla, hur väl stabiliserar sig systemet samt hur kan en trådlös reglering implementeras.  Den slutliga designen bestod av en mikrokontroller som styrde systemet, en vattenpump, en fuktighetssensor och en planta på vilken testerna utfördes. Systemet lämnades i fyra veckor för att se hur väl det klarade sin uppgift. Resultatet blev att växten överlevde vilket innebär att systemet fungerade. Möjligheten att byta ut batterierna mor solceller studerades och slutsatsen är att detta byte är möjligt.
9

Irrigation scheduling, crop choices and impact of an irrigation technology upgrade on the Kansas High Plains Aquifer

Upendram, Sreedhar January 1900 (has links)
Doctor of Philosophy / Department of Agricultural Economics / Jeffrey M. Peterson / The High Plains aquifer is a primary source of irrigation in western Kansas. Since World War II, producers increased irrigation and the irrigated acreage with the widespread adoption of newer irrigation technologies, causing a reduction in the saturated thickness of the High Plains aquifer. In an effort to conserve water and reduce further decline of the aquifer, the state of Kansas administered cost-share programs to producers who upgraded to an efficient irrigation system. But evidence suggests that the efforts to reduce water consumption have been undermined by producers, who under certain conditions have increased irrigation and irrigated acreage of high-valued and water-intensive crops. The state of Kansas is in a quandary to reduce water consumption and stabilize the saturated thickness of the aquifer while maintaining the economic viability of irrigated agriculture. A producer is faced with the choice of crop, irrigation timing and irrigation technology at the start of the season. This research identifies the conditions for risk-efficient crop choices and estimates the effect of an irrigation technology upgrade on the aquifer. Simulation models based on data from Tribune, Kansas were executed under various scenarios, varying by crop (corn or sorghum), irrigation system (conventional center-pivot or center-pivot with drop nozzles) and well capacity (190, 285 or 570 gallons per minute). Each well capacity was associated with a pre-season soil moisture level (0.40, 0.60 or 0.80 of field capacity). Each scenario was simulated over weather data observed during the 36-year period (1971-2006). Results indicate that producers with slower wells could maximize their net returns while conserving water by choosing less water-intensive crops like sorghum, while irrigating with a conventional center-pivot irrigation system. Producers with faster wells could maximize net returns by choosing water-intensive crops like corn and irrigate with the more efficient center-pivot with drop nozzle irrigation system. In order to reduce groundwater consumption and maintain the saturated thickness of the aquifer, water policies should internalize the interests of all stakeholders and be a combination of irrigation technology, economic factors, hydrological conditions, agronomic practices, conservation practices and local dynamics of the region.
10

Steuerung von Bewässerungssystemen im Gewächshaus mit Hilfe des Phytomonitoring

Exarchou, Evanthia 13 April 2006 (has links)
Der verstärkte Wassermangel und die ökologische Belastung durch Düngemittel und Pestizide erfordert eine kontrollierte und präzise Applikation von Wasser und Nährlösung. Die messtechnische Ermittlung des Wasserhaushalts im SPAC-System erfolgt durch Messungen an den einzelnen Komponenten Boden, Pflanze und Atmosphäre. Eine stärkere Aussagekraft über den tatsächlichen Wasserstatus der Pflanze bietet die sensorische Informationsgewinnung an der Pflanze selbst (Phytomonitoring). Ein neuentwickelter Phytomonitor (EPM 2005 bzw. 2006), der auf dem Prinzip einer Gaswechselmessung an einzelnen Pflanzenblättern basiert, wurde zur Messung der momentanen Transpirationsintensität von Pflanzenbeständen eingesetzt. Die Präzision und Repräsentativität der Methode wurde in unterschiedlichen Jahreszeiten unter mitteleuropäischen (Berlin, Deutschland) und südeuropäischen Gewächshausbedingungen (Thessaloniki, Griechenland) getestet. Als Vergleichsbewässerungsverfahren wurden die Saugspannungsregelungsmethode und die Bewässerung nach Zeitsteuerung herangezogen. Gleichzeitig wurden Tensiometer zur Überwachung des Saugspannungsverlaufs im Substrat eingesetzt. Im Vergleich zu weiteren Phytomonitoringsystemen ist dadurch eine bessere Übertragbarkeit der Messdaten auf größeren Pflanzenbeständen gegeben. Die Methode ist dabei nicht sortenspezifisch. Durch ein hohes Bestimmtheitsmaß der Regressionsfunktion der gemessenen Transpirationsmassenstromdichte bzw. Nettophotosyntheseleistung an zwei Standorten der gleichen Konditionen wurde die Homogenität des pflanzlichen Stoffaustausches in Gewächshausbeständen bewiesen. Die Übertragbarkeit der Messdaten auf den gesamten Bestand wurde durch die Bildung der Wasserbilanz über längere Zeitperioden geprüft. Hohe Korrelationen wurden zwischen den gemessenen und den berechneten Transpirationssummen erzielt. Die Bewässerungssteuerung nach den gemessenen Transpirationssummen hat die vorbestimmte Überschussmenge, sogar unter hohen Strahlungs- und Luftfeuchtigkeitsbedingungen, erzielen können. Der durch Tensiometer registrierte Saugspannungsverlauf eines transpirationsgesteuerten Tomatenbestands war vergleichbar zu dem eines tensiometergeregelten Bestandes. Die zwei Bewässerungsmethoden ergaben keine signifikante Unterschiede in der Fruchtanzahl, Blattanzahl oder Pflanzengröße. Das Wasser wurde leicht effizienter in dem tensiometergeregelten Bestand eingesetzt, ohne dass sich die Erträge signifikant unterschieden. Minimalste Drainagemengen ( / The increased shortage of water, were as the ecological pollution through fertilisers and pesticides, requires a controlled and precise amount of water inset. The determination of the water balance in the SPAC-System by technological measurements is reached by measuring on the individual components substrate, plant and atmosphere. The direct measuring on the plant by the Phytomonitoring-Technology is meaningful for the determination of the factual water status of the plant. A new developed Phytomonitoring (EPM 2005 or 2006), which is based on gas exchange measurements of individual plant leaves by cuvettes, was used for measuring the momentary transpirations intensity of plant cultures. The precision and representatively of the method was tested on different seasons under north European (Berlin, Germany) and south European (Thessaloniki, Greece) greenhouse conditions. The tensiometer control method as well as a time-scheduled irrigation system were used for comparison purposes. Tensiometers were used for monitoring the suction course in the substrate. In comparison to other Phytomonitoring-systems gives this one a better transmissibility of the measurement on big canopies. A high coefficient of determination of the regression line between the measured transpirations intensity (and photosynthesis intensity) of two sites with the same conditions, was found. This improves the homogeneity of the mass exchange in greenhouse canopies. Water balances were builded over long periods to prove the transmissivity of the measurements over the whole canopy. The measured transpiration sums were high correlated to the calculated ones (through the water balance equation). The drain target of 20-30% (usual for the practical experience) of the irrigation scheduling method, based on the measured transpiration sum, could be reached even under high radiation and low humidity conditions. The substrate of a tomato stand irrigated after the transpirationsummethod (switch threshold: 3 l transpiration sum, irrigation amount: 4 l) showed a suction-course comparable to the one of a tensiometercontroled stand (switch threshold: 50 hPa, irrigation amount: 3 l). There were no significant differences in the fruit number, leaf number or planthight between the two canopies. The water was efficiently consummated in the tensiometercontroled stand, were as the yields were significantly not different. Minimal drain water amounts (

Page generated in 0.1402 seconds