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1 – 10 of 44Liang Liu, Yuling Zhao, Dongjuan Cheng and Baoguo Ma
Hydraulic conductivity is very low in saline-sodic soil, which decreases water infiltration. For saline-sodic soil, increasing infiltration water has a special meaning. Increasing…
Abstract
Purpose
Hydraulic conductivity is very low in saline-sodic soil, which decreases water infiltration. For saline-sodic soil, increasing infiltration water has a special meaning. Increasing infiltration water not only increases the water in the soil profile but also decreases the salinity of the soil, thus making it suitable for growing crops. This study aims to examine the effect of sand pipes on soil water and salt distribution through laboratory tests with different depths and diameters of sand pipes.
Design/methodology/approach
The soil water and salt distribution responses to different sand pipe depths and diameters was investigated. Treatments included sand pipes with diameters of 4 cm, 5cm, 6 cm and the same depth of 4 cm; with depths of 2cm, 6 cm and the same diameter of 5 cm, and a control with no sand pipe (with the diameter of 0 cm and the depth of 0 cm).
Findings
The results suggested that the amount of cumulative infiltration water and transport distance of the wetting front could be increased by increasing the depth and diameter of sand pipes. The soil water content in the soil profile decreased under all treatments except for the control, whereas the value of EC increased with increasing distance from the film hole center. Positive relationships were also found among the sand pipe depth, diameter and the zone of low salt content. Furthermore, salt leaching depth increased with sand pipe depth and diameter. Overall, the treatments with and without sand pipes exhibited obvious differences.
Originality/value
The correlation analysis proved that increasing the infiltration area through sand pipes positively affected the amount of infiltration water, wetting scope and salt leaching depth.
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H.X. Wu, Yunxin Zhang, Lishu Wang, Dongjuan Chen and Chao Ma
The purpose of this study is to investigate the effect of different infiltration heads on soil water movement using a free infiltration test for small-diameter tube outflow furrow…
Abstract
Purpose
The purpose of this study is to investigate the effect of different infiltration heads on soil water movement using a free infiltration test for small-diameter tube outflow furrow irrigation under mulch film.
Design/methodology/approach
The test consisted of small-diameter tube outflow furrow irrigation under mulch film with three different infiltration heads (3, 4 and 5 cm) and furrow drip irrigation under mulch film using an infiltration head of 4 cm (CK).
Findings
During irrigation, the accumulated infiltration and migration distance of the wetting front increased with time. During the same infiltration time, both the accumulated infiltration and horizontal migration distance of the wetting front increased with the larger infiltration head, whereas the vertical migration distance of the wetting front gradually decreased. With increasing distance from the furrow center, soil moisture content declined, but the uniformity of its distribution increased as the infiltration head increased.
Originality/value
This study can provide scientific basis for the use of small-diameter tube outflow furrow irrigation under mulch film.
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SOME of the general principles of the mechanics of fluids—such for example as the laws of liquid equilibrium—have been known since very early times. Because of this the ancient…
Abstract
SOME of the general principles of the mechanics of fluids—such for example as the laws of liquid equilibrium—have been known since very early times. Because of this the ancient Egyptians were able to produce advanced systems of irrigation and the Romans, much later, their urban water supplies. The crude water wheel, its motive power a bullock or a donkey, replaced man‐power and supplied water to the irrigation ditch while the bucket‐type pump, arranged in stages for short lifts, made deep mining possible. It is somewhat surprising to find that, as early as the seventeenth century, working hydraulic systems were in existence where, cither by a system of balanced buckets or other devices, the prototype of the modern selector valve enabled a continuous supply of water to be maintained.
Using visual materials to understand a social object requires the researcher to know that object's purpose, and this is true whether the object is an artifact, a restricted event…
Abstract
Using visual materials to understand a social object requires the researcher to know that object's purpose, and this is true whether the object is an artifact, a restricted event, a small social world, or something as massive as the modern city. I argue that the purpose of the city as a settlement is driven by the need to safely sleep in peace at night while satisfying other basic biophysical needs during the day as conveniently as possible. An examination of these needs identifies 10 functional prerequisites for human settlement, entangling its inhabitants in involuntary community with entities and events other than themselves, whether they like it or not. In addition, the rise of the modern city exacerbates the challenge of living in a reluctant community and pressures its inhabitants to come to terms with the consequences for how these relationships affect daily life. I highlight nine challenges posed as questions that have been particularly salient in American urban history since the mid-nineteenth century. How these challenges have been addressed indicates not only what it takes to make a modern city a settlement suitable for satisfying human needs, but also just how deeply invested its residents are in making the city work. Finally, the 10 functional prerequisites and nine moral challenges not only provide a framework for researching the city, but also suggest a coherent outline for imagining a “shooting script” or guide for conducting visual research.
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If any single statement during the recent Lancaster House conference was generally accepted it was that Britain's productivity is far from satisfactory. The two things which…
Abstract
If any single statement during the recent Lancaster House conference was generally accepted it was that Britain's productivity is far from satisfactory. The two things which decide a country's productivity are how much of its gross national product it invests and how much it makes that investment earn.
Benjamin Valdez, Michael Schorr, Margarito Quintero, Monica Carrillo, Roumen Zlatev, Margarita Stoytcheva and Juan de Dios Ocampo
The aim of this work is to study the corrosion and scaling factors, mechanisms and processes affecting the materials, equipment and installations of the Cerro Prieto geothermal…
Abstract
Purpose
The aim of this work is to study the corrosion and scaling factors, mechanisms and processes affecting the materials, equipment and installations of the Cerro Prieto geothermal field (GTF).
Design/methodology/approach
The physicochemical characteristics of the geothermal well and fluids were analysed, recorded and related to the corrosion and scaling phenomena.
Findings
The high temperature and salinity of the steam‐brine mixture and the presence of hydrogen sulphide and carbon dioxide impart a severe level of corrosivity.
Originality/value
Corrosion and scaling control assure an efficient production regime, provide for the durability of the GTF engineering materials and equipment and contribute to environmental quality.
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It is more interesting to speculate on the reasons given for the changes made on 1st June last in the sale and availability of vitamin supplements in the Welfare Foods Service…
Abstract
It is more interesting to speculate on the reasons given for the changes made on 1st June last in the sale and availability of vitamin supplements in the Welfare Foods Service than in the action taken. After the date given tokens for free supply of vitamin supplements are invalid and supplies will be sold at prices which cover their cost to the Government, only for the use of expectant and nursing mothers, children under five years and one month and handicapped children. No changes are being made in the arrangements for obtaining liquid milk at the special welfare price of fourpence a pint or National Dried Milk at two shillings and fourpence a tin.
IN A LETTER to the Daily Telegraph last month, it was left to Mr J. Kirby, director of Kirby (Oldham) Ltd to underline the prime cause why statistics of those out of work go down…
The British Productivity Council has recently published a booklet outlining its programme and policy. Emphasis is given to the importance of making available to all engaged in…
Abstract
The British Productivity Council has recently published a booklet outlining its programme and policy. Emphasis is given to the importance of making available to all engaged in industry, including management and trade union officials, information respecting modern production techniques and the economic advantages of their wider application.
Plastic Laboratory Taps. A new range of taps, cocks and fittings made for laboratory use are being introduced into the U.K. by Tough Plastics Ltd. Moulded in nylon, various…
Abstract
Plastic Laboratory Taps. A new range of taps, cocks and fittings made for laboratory use are being introduced into the U.K. by Tough Plastics Ltd. Moulded in nylon, various colours, in polythene and polypropylene, the wide range of designs available makes provision for practically every possible requirement. They are manufactured in Germany.