Seepage Rate from Ceramic Pitchers under Positive and Negative Hydraulic Head

2018 ◽  
Vol 34 (4) ◽  
pp. 707-714 ◽  
Author(s):  
Majed M Abu-Zreig ◽  
Amjed M Zraiqat ◽  
Mohammed Abd Elbaset
Keyword(s):  
Arid Regions ◽  
Hydraulic Head ◽  
Potential Evaporation ◽  
Moisture Condition ◽  
Seepage Rate ◽  
Hydraulic Conditions ◽  
Irrigation Pipes ◽  
Constant Head ◽  
Local Materials ◽  
Supply Water

Picher irrigation is a traditional technique used to supply water to plants under drought conditions in arid regions. Laboratory experiments were conducted to evaluate water seepage rates from ceramic pots/pitchers, made from baked clay-sand local materials, under various environmental and hydraulic conditions. Seven ceramic pots (simulating ceramic emitters) with various dimensions were used in the experiments. Handmade ceramic pots of about 1 L in volume and 26 cm tall were used in the experiment. The hydraulic conductivities of the pots were measured using falling head method and the values ranged from 0.275 to 0.704 mm/d. Seepage rate from ceramic pots were measured in the air and when buried in the soil under constant and falling head method inside a temperature and humidity-controlled chamber. Results indicated that seepage rate is affected by various conditions including potential evaporation, soil suction pressure and moisture condition, and hydraulic head. Seepage rate from ceramic pots were higher under constant head condition and when buried inside soil than that under falling head or in the air. Seepage rates were found to increase steadily with potential evaporation but decrease gradually with increased soil moisture around ceramic pots. The value of hydraulic head seemed to have the largest effect on pitchers’ seepage rate. The seepage rate under a constant head of 30 cm above the mouth of the ceramic pot tested in the experiment was 2500 mL/d but decreased to only 114 mL/d under a constant head of -25 cm below the mouth of the pot. The experiments revealed that ceramic pitchers can be used to supply water even under negative head thus eliminating the need for pressurized flow inside irrigation pipes. Keywords: Arid regions, Drylands, Evaporation, Hydraulic head, Pitcher irrigation, Subsurface irrigation.

scholarly journals Using hydraulic head, chloride and electrical conductivity data to distinguish between mountain-front and mountain-block recharge to basin aquifers

2018 ◽  
Vol 22 (2) ◽  
pp. 1629-1648 ◽  
Author(s):  
Etienne Bresciani ◽  
Roger H. Cranswick ◽  
Eddie W. Banks ◽  
Jordi Batlle-Aguilar ◽  
Peter G. Cook ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Arid Regions ◽  
South Australia ◽  
Hydraulic Head ◽  
Mountain Front ◽  
Quaternary Aquifers ◽  
Groundwater Systems ◽  
Flow Directions ◽  
Electrical Conductivity Data

Abstract. Numerous basin aquifers in arid and semi-arid regions of the world derive a significant portion of their recharge from adjacent mountains. Such recharge can effectively occur through either stream infiltration in the mountain-front zone (mountain-front recharge, MFR) or subsurface flow from the mountain (mountain-block recharge, MBR). While a thorough understanding of recharge mechanisms is critical for conceptualizing and managing groundwater systems, distinguishing between MFR and MBR is difficult. We present an approach that uses hydraulic head, chloride and electrical conductivity (EC) data to distinguish between MFR and MBR. These variables are inexpensive to measure, and may be readily available from hydrogeological databases in many cases. Hydraulic heads can provide information on groundwater flow directions and stream–aquifer interactions, while chloride concentrations and EC values can be used to distinguish between different water sources if these have a distinct signature. Such information can provide evidence for the occurrence or absence of MFR and MBR. This approach is tested through application to the Adelaide Plains basin, South Australia. The recharge mechanisms of this basin have long been debated, in part due to difficulties in understanding the hydraulic role of faults. Both hydraulic head and chloride (equivalently, EC) data consistently suggest that streams are gaining in the adjacent Mount Lofty Ranges and losing when entering the basin. Moreover, the data indicate that not only the Quaternary aquifers but also the deeper Tertiary aquifers are recharged through MFR and not MBR. It is expected that this finding will have a significant impact on the management of water resources in the region. This study demonstrates the relevance of using hydraulic head, chloride and EC data to distinguish between MFR and MBR.

scholarly journals An Analytical Solution for Non-Darcian Flow on a Constant Head Packer Test in the Interlayer Staggered Zone

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Qi Shen ◽  
Zhifang Zhou ◽  
Meng Chen ◽  
Sijia Li ◽  
Zhe Wang ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Power Index ◽  
Injection Pressure ◽  
Hydraulic Head ◽  
Analytic Model ◽  
In Situ Tests ◽  
Specific Storage ◽  
Packer Test ◽  
Baihetan Hydropower Station ◽  
Constant Head

Groundwater flow in an aquifer has frequently been found to be non-Darcian by performing in situ tests. A novel analytic model is proposed in this study for describing the unsteady non-Darcian flow in a confined aquifer by taking advantage of the observed flow rate and injection pressure during the constant head packer test. A linearization approximation of the Izbash equation is used to approximate the nonlinear term in the governing equation. This analytic model is applied to describe the non-Darcian flow in the interlayer staggered zone at the Baihetan hydropower station, China. The test results inversed by the genetic algorithm show that non-Darcian flow happened during the test under the injection pressure 0.3 MPa with the power index n is 1.278, non-Darcian hydraulic conductivity k 1 is 1.613 × 10 − 5  cm/s and the specific storage S s is 9.757 × 10 − 5  m-1, respectively. The sensitivity analysis indicated that when the power index n or the specific storage S s is larger, and the hydraulic head will increase more slowly and needs longer to stabilize, but the non-Darcian hydraulic conductivity k 1 shows the opposite trend. Moreover, the hydraulic head is more sensitive to the power index n compared to other parameters at late times. The findings of this study reveal the non-Darcian flow during the constant head packer test and provide a simple and fast way to estimate parameters for more accurate seepage field simulation.

Effects of Inclination Angle on Archimedes Screw Generator Power Production with Constant Head

2021 ◽  
Vol 147 (3) ◽  
pp. 04021001
Author(s):  
Scott Simmons ◽  
Guilhem Dellinger ◽  
Murray Lyons ◽  
Abdelali Terfous ◽  
Abdellah Ghenaim ◽  
...  
Keyword(s):  
Inclination Angle ◽  
Power Production ◽  
Constant Head

Efficiency of two-stage heating of water on CHP plant with turbines of type T-250/300-240

2019 ◽  
Vol 12 (3) ◽  
pp. 213-219
Author(s):  
E. T. Ilin ◽  
S. P. Pechenkin ◽  
A. V. Svetushkov ◽  
J. A. Kozlova
Keyword(s):  
Transition Period ◽  
Steam Pressure ◽  
Low Pressure ◽  
Heat Extraction ◽  
Two Stage ◽  
Permissible Level ◽  
Lower Heat ◽  
Operational Modes ◽  
Extraction Section ◽  
Supply Water

During non-heating and transition period, most of cogeneration turbines operate with a lower heat extraction section actuated only due to a number of restrictions on the maximum and minimum pressure levels in the upper and lower heat extraction sections at operation of the turbine. For turbines of model T-250/300-240, the minimum permissible level of steam pressure in the upper heat extraction section, according to manufacturer data, is set to 0.06 MPa. During the non-heating and transition period, the supply water temperature is usually set in the range of 70–75°С. In order to maintain that temperature of supply water, the steam pressure in the upper heat extraction section should be below the minimum permissible level. As a result, the turbine operates with only the low-pressure heat extraction section actuated, which ensures operation without restrictions, but with a lower efficiency. The authors have introduced a set of measures, which enable to avoid those restrictions and implement two-stage heating of supply water. In this case, on connection of the upper heating extraction section, the pressure in the same is maintained at the minimum permissible level. Heat output characteristics are provided by having some of supply water delivered bypassing the group of network heaters. This operational mode enables to increase the turbine actual heat drop, to reduce the cooling steam flow into the low-pressure section and, accordingly, into the condenser, and to reduce temperature drops in network water heaters. Results of the research of operational modes for turbines of type T-250/300-240 in the non-heating and transition period with one and two-stage heating are provided. The economic efficiency of proposed operational modes was researched, which shows the effectiveness of those modes during non-heating and transition period. The limits of the efficiency of using these modes are determined.

Pemilihan Tipe Bangunan Pelindung Pantai di Desa Sikeli Berbasis Bahan Lokal

2020 ◽  
Vol 24 (1) ◽  
pp. 100-105
Author(s):  
Herawati Herawati ◽  
Muhammad Arsyad Thaha ◽  
Chairul Paotonan
Keyword(s):  
Analytical Hierarchy Process ◽  
Movement Pattern ◽  
Terrestrial Ecosystems ◽  
Coastal Protection ◽  
The North ◽  
Sea Wall ◽  
Hierarchy Process ◽  
Local Materials ◽  
Current Movement ◽  
Process Method

Abstrak Wilayah pesisir merupakan pertemuan antara wilayah laut dan wilayah darat, dimana daerah ini merupakan daerah interaksi antara ekosistem darat dan ekosistem laut yang sangat dinamis dan saling mempengaruhi. Tujuan penelitian ini adalah untuk menentukan material lokal yang potensial dapat digunakan sebagai bahan bangunan pelindung pantai dan memilih tipe bangunan pelindung pantai yang sesuai kondisi hidro-oseanografi di lokasi studi dengan metode Analythic Hierarchy Process. Lokasi penelitian berada di Provinsi Sulawesi Tenggara, tepatnya di Pulau Kabaena, Kecamatan Kabaena Barat Desa Sikeli kabupaten Bombana. Pulau Kabaena memiliki luas 873 km2. Secara geografis terletak antara 4°22’ 59,4” - 5°28’ 26,7” Lintang Selatan serta antara 121°27’46,7”-122°09’,4” Bujur Timur. Hasil penelitian menunjukkan perairan disepanjang tanjung perak sangat mempengaruhi hidro-oseonografi disekitar pantai desa Sikeli. Kondisi ini berpengaruh terhadap pola pergerakan arus dan tinggi gelombang datang disekitar pantai desa Sikeli. Tinggi gelombang rata-rata yang paling besar merambat dari arah barat sebesar 0.49 m dengan presentase kajadian sebesar 32.42 %, disusul arah barat laut sebesar 0.39 m (20.56 %), arah tenggara sebesar 0.31 m (8.72 %) arah barat daya sebesar 0.31 m (7.99 %), arah utara sebesar 0.20 m (6.94 %), arah timur sebesar 0.15 m (11.81 %), arah selatan sebesar 0.12 m (3.42 %), dan arah timur laut sebesar 0.11 m (8.15 %). Pengambilan keputusan untuk memilih tipe bangunan pelindung pantai dengan metode AHP (Analytical Hierarchy Process) untuk penanganan abrasi pesisir pantai desa Sikeli berbasis bahan lokal diperoleh bahwa alternatif bangunan dengan nilai keterpilihan yang tertinggi adalah detached breakwater (0,4432) disusul groin (0,2479), sea-wall (0,1700) dan revetment (0.1389). Detached breakwater berfungsi untuk menahan laju sedimen kearah laut, mengurangi ketinggian dan meredam energi gelombang dan tidak dibangun sepanjang garis pantai yang akan dilindungi sehingga kapal nelayan dapat ditambat dipesisir pantai dengan aman. Abstract The Selection Type of Coastal Protection Structures in Sikeli Village Based on Local Materials. The coastal area is a meeting point between the sea and land areas, where this area is an area of interaction between terrestrial ecosystems and marine ecosystems which are very dynamic and influence each other. The purpose of this research is to determine local materials that can be used as coastal protection materials and to select the type of coastal protection that is suitable for the hydro-oceanographic conditions in the study location using the Analythic Hierarchy Process method. The research location is in Southeast Sulawesi Province, precisely on Kabaena Island, Kabaena Barat District, Sikeli Village, Bombana Regency. Kabaena Island has an area of 873 km2. Geographically it is located between 4° 22' 59.4"- 5° 28' 26.7" South Latitude and between 121° 27' 46.7 "-122° 09' 4" Longitude East. The results showed that the waters along Tanjung Perak greatly affect the hydro-oseonography around the coast of Sikeli village. This condition affects the current movement pattern and the height of the incoming waves around the coast of Sikeli village. The largest average wave height propagating from the west is 0.49 m with a kajadian percentage of 32.42%, followed by the northwest direction of 0.39 m (20.56%), southeast direction of 0.31 m (8.72%) to the southwest of 0.31 m (7.99%), to the north of 0.20 m (6.94%), to the east of 0.15 m (11.81%), to the south of 0.12 m (3.42%), and to the northeast of 0.11 m (8.15%). The decision to choose the type of coastal protection using the AHP (Analytical Hierarchy Process) method for the coastal abrasion management model in Sikeli village based on local materials was obtained that the alternative building with the highest electability value was the detached breakwater (0.4432) followed by groins (0.2479), sea-wall (0.1700) and revetment (0.1389). The detached breakwater model which functions to restrain the sediment rate towards the sea, reduce the height and reduce wave energy and is not built along the coastline which will be protected so that fishing boats can be moored to the coast safely.

A Process of Glocalisation? Roman Marble Imports and the Rise of Blocked-Out Capitals in Local Stone

2020 ◽  
pp. 33-45
Author(s):  
Matthias Grawehr
Keyword(s):  
Roman Empire ◽  
Eastern Mediterranean ◽  
High Quality ◽  
White Marble ◽  
Aesthetic Preference ◽  
Local Responses ◽  
Global Trend ◽  
Short Period ◽  
New Type ◽  
Local Materials

In the Augustan Age, a new aesthetic preference was propagated in the Roman Empire – the surface of white marble was valued as it symbolised the strength and superiority of the ‘new age’. Soon, an immense trade in high quality marble over land and sea developed to meet the emergent demand. While the development and scale of this trade is well studied, the repercussions that the new aesthetic preference had on the local architectural traditions in areas where no marble was close at hand is not commonly considered. In this contribution, two developments are traced, taking the Corinthian capital as the leitmotif. First, in the short period between c. 40 and 10 BC, patrons would choose imitation of marble in plaster to meet up with the demands of the new standard and to demonstrate their adherence to the Empire. In the second line of development, a different path was taken – a conscious use of local materials which went hand in hand with the development of a new type of capital, the so-called ‘Nabataean blocked-out’ capital. This combination turned into a new vernacular tradition across large parts of the eastern Mediterranean. Both developments were local responses to a new ‘global’ trend and can therefore be viewed as a phenomenon of glocalisation in the Roman Period.

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