scholarly journals Sustainable Biopolymer Soil Stabilization in Saline Rich, Arid Conditions – A ‘Micro to Macro’ Approach.

2021 ◽  
Author(s):  
S. J. Armistead ◽  
C. C. Smith ◽  
S. S. Staniland
Keyword(s):  
Arid Regions ◽  
Soil Stabilization ◽  
Salt Water ◽  
High Strength ◽  
Mining Operations ◽  
Salting Out ◽  
Soil Systems ◽  
Arid Conditions ◽  
Sand Control ◽  
Mineral Binding

Abstract Water scarcity in semi-arid/arid regions is driving the use of salt water in mining operations. A consequence of this shift, is the potentially unheeded effect upon Mine Tailing (MT) management. With existing stabilization/solidification methodologies exhibiting vulnerability to MT toxicity and salinity effects, it is essential to explore the scope for more environmentally durable sustainable alternatives under these conditions. Within this study we investigate the effects of salinity (NaCl, 0-2.5 M) and temperatures associated with arid regions (25 , 40), on Locust Bean Gum (LB) biopolymer stabilization of MT exemplar and sand (control) soil systems. A cross-disciplinary ‘micro to macro’ pipeline is employed, from a Membrane Enabled Bio-mineral Affinity Screen (MEBAS), to Mineral Binding Characterisation (MBC), leading finally to Geotechnical Verification (GV). As predicted by higher Fe2O3 LB binding affinity in the MEBAS studies, LB with 1.25M NaCl, results in the greatest soil strength in the MT exemplar after 7 days of curing at 40 °C. Under these most challenging conditions for other soil strengthening systems, an overall UCS peak of 5033 kPa is achieved. MBC shows the critical and direct relationship between Fe2O3 LB ‘high-affinity’ at the molecular level and ‘high-strength’ achieved at the geotechnical level. This is attributed to biopolymer binding group’s increased availability, with their ‘salting-in’ as NaCl concentrations rises to 1.25M and then ‘salting-out’ at higher concentrations. This study highlights the potential of biopolymers as robust, sustainable, soil stabilization additives in challenging environments.

scholarly journals Developing new lines of Japonica rice for higher quality and yield under arid conditions

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11592
Author(s):  
Mahmoud A.A. El Sayed ◽  
Ahmed M.S. Kheir ◽  
Fatma A. Hussein ◽  
Esmat F. Ali ◽  
Mahmoud E. Selim ◽  
...  
Keyword(s):  
Arid Regions ◽  
Mineral Elements ◽  
Quality Characteristics ◽  
High Yield ◽  
Japonica Rice ◽  
Total Production ◽  
Growing Seasons ◽  
Yield And Quality ◽  
Arid Conditions ◽  
Food Security And Nutrition

Rice is the world’s largest food crop, and its production needs to be doubled by 2050 to cope with population growth and associated demand. In addition to the value of improving yields, quality is also important for breeders and consumers, but it pays less attention in arid regions. During two successive summer growing seasons, the experimental material focused on 34 genotypes developed from different crosses on Fn generation after fixation as well as six of the most recent commercial cultivars used for comparisons. The results showed that a high yield of grain followed by high milling and grain quality characteristics were observed among the 34 genotypes used in this analysis. Highly important and positive correlations between the percentage of hulling and the percentage of milling (0.424) and the yield ability could be accomplished by choosing the number of panicles per plant and the weight of the panicles. Selection criteria for good quality should be met by the percentage of head rice and many mineral elements, particularly zinc and iron. As a consequence, the genotypes M.J 5460S/SK105-1, M.J 5460S/GZ7768-1, M.J 5460S/G177-1, M.J 5460S/SK105-3 and M.J 5460S/SK106-4 had desirable high yield and quality characteristics and could be used as promising accessions to the rice breeding program in arid regions. In addition to commercial genotypes, improved Japonica rice genotypes could be produced in arid conditions for higher yield and quality, leading to an increase in total production, supporting food security and nutrition.

Deepstar Hull Fabrication

1965 ◽  
Vol 2 (04) ◽  
pp. 360-369
Author(s):  
George F. Gayer
Keyword(s):  
Salt Water ◽  
Water Environment ◽  
Welding Process ◽  
High Strength ◽  
Automatic Welding ◽  
Electric Motors ◽  
Camera Port ◽  
Ac Power ◽  
Welding Alloy ◽  
Private Venture

Deepstar is a self-propelled, manned vehicle for deep-sea research. It is being built as a private venture by Westinghouse Underseas Division, Baltimore, under a technical exchange license with Captain Cousteau and the OFRS (Office Francais de Recherches Sous-Marines) of Marseilles, France. Deepstar is designed to carry a crew of three to depths of 4000 ft for periods up to 24 hr. It is powered by two 4½-hpbattery-operated electric motors which propel it at about 3 knots, with a maximum range of about 20 miles. Overall dimensions of the vehicle are 13 ft long by 7 ft high by 11½ft wide over the fairing. The pressure sphere which houses the crew was built for our Baltimore Underseas Division by Westinghouse, Sunnyvale Marine Division. It measures 70 in. od and was fabricated from two hemispheres of high-strength steel. These hemispheres were spun from alloy plates 1?in. and then machined both inside and outside to 1.2 in. thick. Accurate machining was essential to maintain the sphericity required for pressure stability. After machining, the two hemispheres were welded together by an automatic welding process. The sphere has a total of 11 penetrations through the shell, including an access hatch, 2 viewports, a camera port, 2 electrical passages and 5 shaft openings. Reinforcements for the larger openings were made by welding alloy-steel forgings into the shell. Small openings were reinforced by weld metal buildup through which holes were drilled. All reinforcements were then machined to provide accurate penetrations and sealing surfaces. An extensive metallurgical testing program was conducted to insure that all material and welding used in the sphere had the strength and toughness required for operation at maximum depths. Pressure tests have been conducted in a chamber to 1.2 maximum operating depth. Sunnyvale also made the electric motors for Deepstar. These free-flooded ac motors are suspended outside the pressure hull. Unusual problems solved by special processing included electrical insulation in the salt water environment and water-lubricated bearings. AC power for the motors is provided from the batteries through a rotary inverter with semi-conductor controls.

Shear Strength of BC-Soil Admixed with Lime and Bio-Enzyme

2019 ◽  
Vol 969 ◽  
pp. 327-334
Author(s):  
C. Jairaj ◽  
M.T. Prathap Kumar ◽  
H. Muralidhara
Keyword(s):  
Shear Strength ◽  
Soil Stabilization ◽  
Morphological Changes ◽  
Ground Improvement ◽  
High Strength ◽  
Sem Analysis ◽  
Dry Density ◽  
Test Results ◽  
Maximum Dry Density ◽  
Lime Content

This BC Soil are expansive in nature and are problematic because of low shear strength and high compressibility. Review of literatures have proven that addition of lime imparts high strength with a corresponding reduction in swell of BC soils. In addition, Bio-enzymes have also been found to play a key role as activators in improving the characteristics of clayey soils such as BC soil. Development and use of non-traditional ground improvement techniques such as bio-enzymes in combination with lime for soil stabilization helps to reduce the cost and the detrimental effects on the soil environment. In the present study lime and bio-enzymes were used as soil stabilizing agents. Compaction test results on BC soil admixed with different percent of lime indicated that 3% addition lime gives higher maximum dry density of 17kN/m3 with OMC of 21% compare to other addition of lime percentages. Keeping 3% of lime as optimum lime content(OLC), BC Soil was admixed with different dosages of Bio-enzymes 25ml/m3, 50ml/m3, 100 ml/m3,150ml/m3, and 200ml/m3 along with OLC was tested for compaction and unconfined compressive strength(UCC). Further UCC test was carried out for different curing period of 0, 7, 15, 30, and 60 Days to analyse the long term effect of BC soil admixed with bio-enzymes with and without lime content. Morphological and chemical analysis was done by using XRD and SEM analysis, from all the test results it was found that 3%OLC + 75ml/m3 of bio-enzymes for 7 day of curing gives higher UCC of 450 kPa. From the SEM it was found that better bond between particles found to develop in bio-enzyme+ lime admixed BC soil in comparison with lime alone admixed BC soil. XRD studies indicated morphological changes in crystallinity and structure of stabilized BC soil in comparison to BC soil alone.

Fractographic Interpretation of Subcritical Cracking in a High Strength Titanium Alloy (IMI 550)

CORROSION ◽  
1973 ◽  
Vol 29 (11) ◽  
pp. 435-441 ◽  
Author(s):  
R.J. H. WANHILL
Keyword(s):  
Titanium Alloy ◽  
Liquid Metal ◽  
Subcritical Crack Growth ◽  
Salt Water ◽  
High Strength ◽  
Treated Condition ◽  
Heat Treated ◽  
Heat Treated Condition ◽  
Subcritical Fracture ◽  
Subcritical Cracking

Abstract A detailed fractographic study of subcritical crack growth in 3.5% aqueous NaCl and liquid mercury was made for IMI 550 (Ti-4AI-4Mo-2Sn-0.5Si) in an (α + β) heat treated condition. The work of Cox and Ajtchison, which showed that river markings are at high angles to genuine cleavage planes, is confirmed. Mechanisms for formation of the river markings are postulated, and a distinction is made between the cleavage topographies in salt water and mercury. Support is also found for the mechanism of liquid metal embrittlement postulated by Hancock and Ives. The overall appearance of the subcritical fracture surfaces provides an explanation for the low KISCC (salt water) customarily found for IMI 550.

Corrosion-Fatigue Crack Propagation Studies of Some New High-Strength Structural Steels

1969 ◽  
Vol 91 (4) ◽  
pp. 570-574 ◽  
Author(s):  
T. W. Crooker ◽  
E. A. Lange
Keyword(s):  
Stress Intensity Factor ◽  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Salt Water ◽  
High Strength ◽  
Structural Steels ◽  
Stress Intensity Factor Range ◽  
Corrosion Fatigue Crack ◽  
Crack Growth Rates

Fatigue crack propagation studies were conducted on three new high-strength structural steels: 9Ni–4Co–0.20C quenched-and-tempered, 10Ni–2Cr–1Mo–8Co dual-strengthened, and 13Cr–8Ni–2Mo precipitation-hardened stainless. The yield strengths of these steels ranged from 176 to 193 ksi. Notched cantilever-bend specimens of each steel were cycled zero-to-tension in two environments, room air and 3.5 percent NaCl salt water. Fatigue crack growth rates were measured experimentally and correlated with the crack tip stress-intensity factor range. The results indicate that these new steels possess greater resistance to fatigue crack propagation and less sensitivity to environment than previously studied steels of comparable strength.

scholarly journals New species of Xiphoscelis Burmeister, 1842 (Coleoptera, Scarabaeidae, Cetoniinae) from arid regions of South Africa and Namibia

ZooKeys ◽  
2019 ◽  
Vol 879 ◽  
pp. 57-89
Author(s):  
Renzo Perissinotto ◽  
Petr Šípek
Keyword(s):  
South Africa ◽  
New Species ◽  
Arid Regions ◽  
Instar Larva ◽  
Western Cape ◽  
Defence Mechanism ◽  
Diagnostic Features ◽  
Arid Conditions ◽  
Brown Colour ◽  
African Genus

Two new species of the southern African genus Xiphoscelis Burmeister, 1842 are recognised and described, X. braunsisp. nov. from the Eastern and Western Cape Karoo (South Africa) and X. namibicasp. nov. from the Huns Mountains of southern Namibia and adjacent ranges in South Africa. These were previously overlooked and grouped together with X. schuckardi Burmeister, 1842, but further material and more in-depth analyses have now revealed their clear separation on the basis of key diagnostic features, including clypeal structure, metatibial spur development and aedeagal shape. The densely and coarsely costate elytral structure and the black to brown colour of these species are symplesiomorphies shared with a number of the most primitive genera among the African Cetoniinae. However, these characters also reflect the convergent adaptation to hot and arid conditions they share with several other species occurring in this region. Phylogenetic relationships of the genus with other Cetoniinae are explored using the larval characters highlighted in the description of the 3rd instar larva of X. braunsisp. nov. The extraordinary hypertrophy observed in the male metatibial spur of species in this genus, and particularly in X. schuckardi, appears to represent a defence mechanism against potential predators on the ground, apart from playing a role during mating.

Study on Quality Control of the Laser Welding Joint

2013 ◽  
Vol 442 ◽  
pp. 276-281
Author(s):  
Qiang Wu ◽  
Lan Ying Xu
Keyword(s):  
Laser Welding ◽  
Salt Water ◽  
Harmful Effect ◽  
Welding Process ◽  
High Strength ◽  
Galvanized Steel ◽  
Welding Parameters ◽  
Test Results ◽  
Welding Joint ◽  
Corrosion Rates

During laser welding process of high-strength galvanized steel, adopting guiding arc plate and the connecting arc plate can avoid harmful effect resulted in unstable melting width. The galvanized layer protecting joint is inevitably lost by having been burned, which affects stain resistance of welding joint. So salt water with the concentration of 3% is used in the corrosion test for the samples welded under different laser parameters, mass variation and metallographic microscopes are gained after joint being corroded. The test results indicate that the corrosion rates of the joint are different under different welding parameters during laser welding of high-strength galvanized steel; their average corrosion rates are coincident with that of base metal and laser welding technology hardly effect corrosion resistance of the joint.

Solar thermal driven desalination plants based on membrane distillation

2003 ◽  
Vol 3 (5-6) ◽  
pp. 49-55 ◽  
Author(s):  
J. Koschikowski ◽  
M. Wieghaus ◽  
M. Rommel
Keyword(s):  
Rural Areas ◽  
Arid Regions ◽  
Potable Water ◽  
Sea Water ◽  
Salt Water ◽  
Membrane Distillation ◽  
Water Output ◽  
Thermally Driven ◽  
Technical Simplicity ◽  
Desalination Plants

In arid and semi-arid regions the lack of drinkable water often corresponds with a high solar insolation. These conditions are favourable for the use of solar energy as the driving force for water treatment systems. Especially in remote rural areas with low infrastructure and without connection to a grid, smallscale, stand-alone operating systems for the desalination of brackish water from wells or salt water from the sea are desirable to provide settlements with clean potable water. Fraunhofer Institut für Solare Energiesysteme is currently developing a solar thermally driven stand alone desalination system. The aim is to develop systems for a capacity range of 0.2 to 10 m3/day. Technical simplicity, long maintenance-free operation periods and high quality potable water output are very important aims for successful applications of the systems. The separation technique that the system is based on is membrane distillation. The implemented heat source is a corrosion-free, sea water resistant thermal collector.

scholarly journals Application of fibre composite grids as reinforcement of foamed PC and GP concrete

2019 ◽  
Vol 274 ◽  
pp. 05002 ◽  
Author(s):  
Rafał Krzywoń ◽  
Jacek Hulimka ◽  
Agnieszka Jędrzejewska ◽  
Marcin Górski
Keyword(s):  
Porous Materials ◽  
Soil Stabilization ◽  
Fibre Composite ◽  
Concrete Slab ◽  
High Strength ◽  
Main Direction ◽  
Tensile Zone ◽  
Composite Grids ◽  
Cellular Concrete ◽  
Aggregate Particles

Cellular concretes cannot be reinforced as easily as traditional ones. Generally porous materials do not ensure sufficient bond of reinforcement; additionally, due to limited amount of aggregate, interlock between aggregate particles and reinforcement ribs is not satisfactory. The idea of reinforcement presented in the paper incorporates bi-directional composite reinforcing grids placed in tensile zone of the cellular concrete slab where transverse fibres are ensuring anchorage for fibres located in the main direction of stresses. The concept is based on geotechnical applications where grids are commonly used as soil stabilization, but the grids adopted in this solution are much stronger thanks to introduction of high strength fibres as composite reinforcement.

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