Emitter

The effects of water temperature and structural parameters of a labyrinth emitter on drip irrigation hydraulic performance were investigated. The inside structural parameters of the trapezoidal labyrinth emitter include path width (W) and length (L), trapezoidal unit numbers (N), height (H), and spacing (S). Laboratory experiments were conducted using five different types of labyrinth-channel emitters (three non-pressure compensating and two pressure compensating emitters) commonly used for subsurface drip irrigation systems. The water temperature effect on the hydraulic characteristics at various operating pressures was recorded and a comparison was made to identify the most effective structural parameter on emitter performance. The pressure compensating emitter flow exponent (x) average was 0.014, while non-pressure compensating emitter’s values average was 0.456, indicating that the sensitivity of non-pressure compensating emitters to pressure variation is an obvious characteristic (p < 0.001) of this type of emitters. The effects of water temperature on emitter flow rate were insignificant (p > 0.05) at various operating pressures, where the flow rate index values for emitters were around one. The effects of water temperature on manufacturer’s coefficient of variation (CV) values for all emitters were insignificant (p > 0.05). The CV values of the non-pressure compensating emitters were lower than those of pressure compensating emitters. This is typical for most compensating models because they are manufactured with more elements than non-compensating emitters are. The results of regression analysis indicate that N and H are the essential factors (p < 0.001) to affect the hydraulic performance.

Increasing urbanization in India is generating huge quantities of wastewater resulting in several environmental problems. Thus, use and dispose approach has to be dispensed with for use and reuse approach. Agriculture, a major consumer of good quality water, could be one sector to consume such marginal quality waters. Although surface irrigation is widely used for irrigation with waste water, drip irrigation could be suitable for sewage water reuse as it minimises the health risk to the farmers (avoids direct contact both of the person and the produce) and consumers. Since emitters and filter clogging would limit the performance of drip irrigation system, it might discourage the farmers from lapping up this technology. This paper gives a brief overview of the results of experimental trials for using sewage water on the behaviour of two kinds of filters i.e. sand and screen filters attached in series and using labyrinth type of emitters, considered most suitable against clogging. The performance of the filters recommended for clean water was inadequate for sewage water (suspended solid 100 mg l-1 and BOD ranging from 45-200 mg l-1). The operating time of the filters between cleaning operations in the case of screen filter was less than one hour causing inconvenience in operations while in the case of sand filter head losses increased from 3.1 m to 7.9 m. Clogging of the filters caused inconvenience in irrigation and energy loss went up to 100%, thus increasing input cost. The results also revealed that reduction in flow rate of the emitters was only 0.5% in the case of surface drippers, which increased to 12% in the case of subsurface drip irrigation. The coefficient of variation increased from an initial value of 0.08 to 0.16 for surface and from 0.08 to 0.23 for subsurface drip irrigation. As it is expected, clogging resulted in reduced application efficiency and reduction was from its initial value of 92 to 85% and 72% in the case of surface and subsurface drip irrigation, respectively.

Pada saat ini PID kontroller masih banyak digunakan di berbagai sektor industri, karena ketang-guhannya untuk menghandel permasalahan yang ada di industri, tetapi terdapat satu kekurangan yaitu metode tuning, proses tuning harus dilakukan dengan cara coba - coba. Prosedur tuning lebih banyak dilakukan secara manual dengan metode trial and error yang belum tentu benar, untuk mengatasi permasalahan tersebut dibutuhkan suatu pendekatan alternatif yang dapat mencapai suatu tingkat automasi dari proses tuning dan orang yang melakukan proses tuning tidak harus memiliki pengetahuan luas mengenai sistem pengaturan. Dalam kasus ini metode alternatif yang digunakan adalah Genetic Algorithm (GA). GA diimplementasi untuk mendapatkan kombinasi parameter P,I, dan D dari kontroler PID dalam simulasi pengaturan kecepatan motor induksi tiga fasa sehingga kecepatan motor dapat dipertahankan agar sama dengan kecepatan referensi dalam steady-state. Hasil dari simulasi yang dilakukan menunjukkan bahwa r...

In this paper, we examine the discharge of labyrinth-channel emitters under different operating pressures (P) and water temperatures (T). An artificial neural network (ANN) and multiple linear regression (MLR) model are developed for the emitter flow variation (qvar) and the manufacturer’s coefficient of variation (CV). As well as P and T, the structural parameters of the labyrinth emitter are considered as independent variables. The ANN results demonstrate that a feed-forward back-propagation network with five input neurons and 14 neurons in the hidden layer successfully model qvar and CV. The trapezoidal unit spacing and path length of the labyrinth emitter are found to be insignificant. In our ANN model, we use a hyperbolic tangent as the activation function in the hidden layer and the output layer. Statistical criteria indicate that the ANN is better at predicting the hydraulic performance of the labyrinth emitters than MLR. The root mean square errors for qvar and CV are 1.0497 and 0.0044, respectively, for the ANN model, and 2.0703 and 0.0107, respectively, for the MLR model using a test dataset. The relatively low errors obtained by the ANN approach lead to high model predictability and are feasible for modeling the hydraulic performance of labyrinth emitters.

Background and objectives: Emitters discharge influenced by various factors such as pressure, manufacturing coefficient of variation, clogging or irrigation water temperature changes. Emitting pipes according to the hydraulic and technical specifications, the use of them in the trickle irrigation systems are increasing.Therefore investigation of the relationship between discharge – pressure and discharge- temperature is required in these pipes in order to improve the efficiency of trickle irrigation systems. Maroufpoor and Parvini(2012) fund with investigation of the relationship between discharge – pressure and discharge- temperature.That in all emitter and tested temperatures power of the discharge - pressure equation was less than 0.2 and all of were emitters pressure compensating. The effect of temperature on the discharge 3 emitter at 95 percent significant and was non-significant other emitters.
Materials and Methods: In order to evaluate the effect of temperature and pressure on emitters discharge, 8 emitting pipe, 6 type of non-compensating and 2 compensating was tested on the constructed physical model of drip irrigation in the water laboratory of University of Kurdistan. In each experiment, according to the standard on every model from the emitting pipes slices, 25 slices were selected randomly. Each slices was consists of 5 units emitters. Slices length varied proportional to the distance of unit’s emitters in the range of 2 to 5 m. The effects of four different water temperatures (13, 23, 33 and 43°C) with different pressure ranges (between zero and 1.2 times more than the maximum pressure) on the emitters were evaluated. The thermostat and element were used to supply water temperatures of 23, 33 and 43 ° C. To supply water temperatures 13 ° C was used of the ice pieces. Generally in the every temperature, discharge of compensating emitting pipes was measured at 10 pressures and in the non-compensating emitting pipes was measured at 7 pressures. Data analysis was performed in a randomized complete block design using SAS software.
Results:According to the results obtained from the experiments of discharge- pressure at all temperatures, in the both C1 and C4 emitting pipes, power of the discharge - pressure equation was less than 0.2,therefore, as compensating are acceptable and were good degree of them flexibility. As well as in the rest of the emitting pipes power of equation was variable between 0.2 and 1 and as non-compensating and them flexibility was the high degree of flexibility. According to the results obtained from the experiments discharge – temperature, in the all emitting pipes of non-compensating, the effect of temperature on discharge at 95 percent was significant, that generally discharge had increased with increasing temperature. In the compensating emitting pipes with increasing temperature from 13 °C to 23 °C, flow rate has increased at 95 percent significantly, but from temperature of 23 °C to temperature 43 °C there was no significant difference between emitters discharge.
Conclusion: In general it can be concluded that the relationship discharge – pressure in the external and internal emitting pipes of common market is acceptable and desirable. Also is suggested that, in the design of trickle irrigation systems that is used emitting pipes, was ensured the effect of temperature on the discharge of emitting pipes units and the necessary correction coefficients is applied emitter nominal flow rate.

Multitrack electrospray chips (MTEC) were fabricated by UV-photoablation of polyethylene terephthalate (PET) substrates. They are composed of an array of up to six microchannels that are successively used as electrospray ionization (ESI) emitters for mass spectrometry (MS). There is no requirement for alignment of the different spraying microchannels with the mass spectrometer orifice. The MTEC is thus fixed in front of the mass spectrometer and the successive MS analyses are performed without moving the chip. The sequential electrospraying by successive application of an identical high voltage in each off-axis microchannel was evaluated for the fast screening of peptides and proteins. The counting of cysteines in peptides through chemical modification and the relative quantification of a peptide in two samples are presented herein as two original strategies based on this new analytical tool. Copyright © 2006 John Wiley & Sons, Ltd.