The influence of water potential, moisture, and temperature on sound speed and the hysteretic nonlinearity parameter of granular materials

2007 ◽  
Vol 122 (5) ◽  
pp. 3060
Author(s):  
Zhiqu Lu
Keyword(s):  
Water Potential ◽  
Granular Materials ◽  
Sound Speed ◽  
Nonlinearity Parameter ◽  
Influence Of Water ◽  
Hysteretic Nonlinearity

scholarly journals A mesoscopic model for compression of granular materials

2018 ◽  
Vol 183 ◽  
pp. 01054
Author(s):  
Elisha Rejovitzky
Keyword(s):  
Experimental Data ◽  
Wave Propagation ◽  
Granular Materials ◽  
Mechanical Model ◽  
Sound Speed ◽  
Bulk Material ◽  
High Sensitivity ◽  
Water Fraction ◽  
Protective Structures ◽  
Solid Spheres

The design of protective structures often requires numerical modeling of shock-wave propagation in the surrounding soils. Properties of the soil such as grain-grading and water-fraction may vary spatially around a structure and among different sites. To better understand how these properties affect wave propagation we study how the meso-structure of soils affects their equation of state (EOS). In this work we present a meso-mechanical model for granular materials based on a simple representation of the grains as solid spheres. Grain-grading is prescribed, and a packing algorithm is used to obtain periodic grain morphologies of tightly packed randomly distributed spheres. The model is calibrated by using experimental data of sand compaction and sound-speed measurements from the literature. We study the effects of graingrading and show that the pressures at low strains exhibit high sensitivity to the level of connectivity between grains. At high strains, the EOS of the bulk material of the grains dominates the behavior of the EOS of the granular material.

Effect of water stress on partitioning of 14C-labelled photosynthates in Vitis vinifera

2004 ◽  
Vol 31 (7) ◽  
pp. 697 ◽  
Author(s):  
Josefina Bota ◽  
Oleg Stasyk ◽  
Jaume Flexas ◽  
Hipólito Medrano
Keyword(s):  
Water Stress ◽  
Vitis Vinifera ◽  
Water Potential ◽  
Distribution Pattern ◽  
Potential Gradient ◽  
Vitis Vinifera L ◽  
Gradient Theory ◽  
Influence Of Water ◽  
Total Plant ◽  
Sink Size

The influence of fruits on export and distribution of photosynthates was studied in Vitis vinifera L. cv. Tempranillo using 14C labelling. Also, the influence of water stress was analysed in fruiting and fruitless plants of Tempranillo and fruiting plants of cv. Alfonso Lavallée. In fruitless plants of Tempranillo, reserve organs (trunk, roots and lower shoot) represented 80% of total plant dry matter (DM), and imported up to 90% of the total 14C exported from the fed leaf. Therefore, the distribution pattern of photosynthates in these plants reflected mainly the sink size. However, the presence of fruits in Tempranillo strongly stimulated 14C export and changed the distribution pattern of assimilates. Fruits imported up to 70–80% of the total 14C exported, while representing only 25% of the total plant DM. Therefore, the strength of fruits as carbon sinks was independent of sink size, and it is discussed on the basis of a water potential gradient theory. Water stress caused a significant reduction of leaf water potential, photosynthesis and stomatal conductance, but caused only a slight, non-significant, decrease of carbohydrate export from the fed leaves, and did not affect the distribution pattern of 14C except in some minor fractions in Tempranillo. The 14C distribution into different fruit components was also unaffected. In contrast, in Alfonso Lavallée water stress resulted in a highly significant reduction of export, and an altered photosynthate distribution pattern. These differences could be due to the lower water potential attained in stressed Alfonso Lavallée plants.

Influence of water potential on nitrification and structure of nitrifying bacterial communities in semiarid soils

2008 ◽  
Vol 40 (1) ◽  
pp. 189-194 ◽  
Author(s):  
Deirdre B. Gleeson ◽  
Anke M. Herrmann ◽  
Stephen J. Livesley ◽  
Daniel V. Murphy
Keyword(s):  
Water Potential ◽  
Bacterial Communities ◽  
Semiarid Soils ◽  
Influence Of Water

Influence of water potential on the survival and saprophytic activity of Rhizoctonia solani AG 4 in natural soil

1985 ◽  
Vol 63 (12) ◽  
pp. 2364-2368 ◽  
Author(s):  
R. C. Ploetz ◽  
D. J. Mitchell
Keyword(s):  
Rhizoctonia Solani ◽  
Water Potential ◽  
Fine Sand ◽  
Natural Soil ◽  
Intermediate Water ◽  
Water Potentials ◽  
Influence Of Water ◽  
General Survival

The survival of Rhizoctonia solani AG 4 was monitored in a natural Arredondo fine sand incubated under controlled water potentials. In general, survival was greater in soils held at intermediate water potentials of −2 to −15 bars (1 bar = 100 kPa) than in moister or drier soils. Saprophytic colonization of rye stem pieces by R. solani AG 4 in artificially infested, natural soil occurred at five water potentials ranging from −0.05 to −15 bars. Colonization did not occur at −1500 bars. Maximum colonization at any of the former water potentials was detected 1 or 2 days after the beginning of an experiment, but it decreased rapidly after 3 days.

Influence of Water Potential on Growth of Shiitake Mycelium

Mycologia ◽  
1989 ◽  
Vol 81 (3) ◽  
pp. 464 ◽  
Author(s):  
Edmond R. Badham
Keyword(s):  
Water Potential ◽  
Influence Of Water

scholarly journals Influence of water stress on grape quality and aroma precursors in Sauvignon Blanc grown in Bolgheri area (Tuscany)

2019 ◽  
Vol 13 ◽  
pp. 03001 ◽  
Author(s):  
Eleonora Cataldo ◽  
Linda Salvi ◽  
Francesca Paoli ◽  
Sofia Sbraci ◽  
Giovan Battista Mattii
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Leaf Gas Exchange ◽  
Stem Water Potential ◽  
Phenological Stages ◽  
Sauvignon Blanc ◽  
Single Leaf ◽  
Grape Quality ◽  
Influence Of Water ◽  
Aroma Precursors

Climate change has a direct impact on the phenological stages of the grapevine, with consequences on the anticipation of aging and on the qualitative characteristics of the grapes. In fact, there is a decrease in the skin/pulp ratio, with possible reduction of the aromatic potential. This work was aimed at assessing the effects of water stress on technological maturity and thiol precursors of Sauvignon Blanc grapes in two vineyards of Bolgheri. To this purpose, 3 theses have been established: WW, well watered; WS, moderate stress; CTRL, control. During the season, measurements of single leaf gas exchange, stem water potential were made; moreover parameters of technological maturity (° Brix, acidity, pH and berry weight) and thiol precursors were analyzed. As expected, the water potential was less negative in the irrigated thesis due to the greater availability of water, as well as the highest rates of photosynthesis, transpiration and stomatal conductance. Technological analyses showed no significant differences among the treatments. The analysis of the 3MH/3-mercaptoesan-1-ol precursors showed that the WW had a greater accumulation than the other theses. These results suggest that lower water stress favors a better aromatic content.

INFLUENCE OF WATER STRESS CONDITIONING ON PHOTOSYNTHETIC WATER STRESS RESPONSE OF SWITCHGRASS (PANICUM VIRGATUM L.) AND TALL FESCUE (FESTUCA ARUNDINACEA SCHREB.)

2001 ◽  
Vol 49 (1) ◽  
pp. 15-24 ◽  
Author(s):  
Z. Kiss ◽  
D. D. Wolf
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Tall Fescue ◽  
Festuca Arundinacea ◽  
Panicum Virgatum ◽  
Leaf Water ◽  
Panicum Virgatum L ◽  
Influence Of Water ◽  
Stress Cycles

The objective of this study was to investigate the influence of water stress conditioning on the photosynthesis response of switchgrass (Panicum virgatum L.) and tall fescue (Festuca arundinacea Schreb.) to moisture deficiency. Tillers of the two species were grown in the same, controlled, environment and were subjected to three conditioning water stress cycles, or were kept well watered. After drought conditioning all plants were subjected to moisture deficiency while photosynthesis and leaf water potential were monitored. Measurements were taken between –0.8 and –4.0 MPa and the rate of water stress was 0.49 MPa/day. The conditioning of switchgrass produced a 26% reduction in the photosynthesis rate during drought, while that of tall fescue produced a 57% reduction in photosynthesis. Both species maintained elongation and photosynthesis down to lower leaf water potentials after drought conditioning than before conditioning. The conditioning water stress cycles decreased the leaf conductance, mesophyll resistance and transpiration of tall fescue plants after rewatering. The leaf water potential of conditioned switchgrass plants was lower upon rewatering after three conditioning water stress cycles than the leaf water potential of non-conditioned plants, while the leaf conductance, mesophyll resistance and transpiration of conditioned and non-conditioned tillers were equal. These data indicate an improvement in the drought tolerance of tall fescue and switchgrass plants, emphasize the importance of knowing the previous water stress history of the plants in moisture deficiency experiments, and help to choose proper irrigation management for switchgrass and tall fescue.

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