scholarly journals Study on the Hydrothermal Coupling Characteristics of Polyurethane Insulation Boards Slope Protection Structure Incorporating Phase Change Effect

2021 ◽  
Author(s):  
Hailiang Liu ◽  
Donghe Ma ◽  
Changming Wang ◽  
Xiaoyang Liu ◽  
Di Wu ◽  
...  
Keyword(s):  
Phase Change ◽  
Water Content ◽  
Field Tests ◽  
Freezing And Thawing ◽  
Slope Structure ◽  
Before And After ◽  
Hydraulic Infrastructure ◽  
Water Conveyance ◽  
Coupling Characteristics ◽  
Relationship Of

Abstract As an important hydraulic infrastructure, the canals are essential for agricultural irrigation, shipping and industry. In the seasonal freeze regions, the water conveyance canals are damaged due to the effects of freeze-thaw cycles. The freeze depth of soil in the water transfer canal varies considerably due to changes in temperature and water content. The paper compares the relationship of the freeze depth, temperature and water content by field tests and numerical calculation methods Incorporating phase change. The results show that the decrease in temperature causes the water in the soil to freeze, the ice front migrate downwards, and the water in soil below ice front gradually migrate towards the ice front, resulting a large difference in water content of the soil before and after freezing. An insulation slope structure, Polyurethane insulation board + Concrete board slope structure (PC), is proposed in this paper to mitigate the effect of freezing and thawing on the water conveyance canals. Under the protective effect, the freeze depth decreases significantly. In addition, this paper compares the anti-frost effect of different thicknesses polyurethane insulation boards, and the results can provide a reference for the anti-frost design of water conveyance canals.

scholarly journals Study on the hydrothermal coupling characteristics of polyurethane insulation boards slope protection structure incorporating phase change effect

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hailiang Liu ◽  
Donghe Ma ◽  
Changming Wang ◽  
Xiaoyang Liu ◽  
Di Wu ◽  
...  
Keyword(s):  
Phase Change ◽  
Water Content ◽  
Field Tests ◽  
Freezing And Thawing ◽  
Slope Structure ◽  
Before And After ◽  
Hydraulic Infrastructure ◽  
Water Conveyance ◽  
Coupling Characteristics ◽  
Relationship Of

AbstractThe canals are essential for agricultural irrigation, shipping and industry as important hydraulic infrastructure. In the seasonal freeze regions, the water conveyance canals are damaged due to the effects of freeze–thaw cycles. The freeze depth of soil in the water transfer canal varies considerably due to changes in temperature and water content. This paper compared the relationship of freeze depth, temperature and water content by field tests and numerical calculation methods by incorporating phase change. The results from present study showed that the decrease in temperature causes the water in the soil to freeze, the ice front migrated downwards, and the water in soil below ice front gradually migrated towards the ice front resulting in a large difference in water content of the soil before and after freezing. The Polyurethane insulation board + Concrete board slope structure (PC) as an insulation slope structure was proposed in this paper to mitigate the effect of freezing and thawing on the water conveyance canals. The freeze depth decreased significantly under the protective effect. In addition, this paper compared the anti-frost effect of different thicknesses of polyurethane insulation boards, and the results provided a reference for the anti-frost design of water conveyance canals.

Locating Al in the DABCO catalyst before and after Al extraction

1990 ◽  
Vol 48 (4) ◽  
pp. 265-267
Author(s):  
Kathleen B. Reuter
Keyword(s):  
Active Site ◽  
Inverse Relationship ◽  
Transverse Direction ◽  
Reaction Rate ◽  
Acid Phosphate ◽  
Fracture Surfaces ◽  
Al Content ◽  
Before And After ◽  
Relationship Of

The reaction rate and efficiency of piperazine to 1,4-diazabicyclo-octane (DABCO) depends on the Si/Al ratio of the MFI topology catalysts. The Al was shown to be the active site, however, in the Si/Al range of 30-200 the reaction rate increases as the Si/Al ratio increases. The objective of this work was to determine the location and concentration of Al to explain this inverse relationship of Al content with reaction rate.Two silicalite catalysts in the form of 1/16 inch SiO2/Al2O3 bonded extrudates were examined: catalyst A with a Si/Al of 83; and catalyst B, the acid/phosphate Al extracted form of catalyst A, with a Si/Al of 175. Five extrudates from each catalyst were fractured in the transverse direction and particles were obtained from the fracture surfaces near the center of the extrudate diameter. Particles were also obtained from the outside surfaces of five extrudates.

Richard Scheringer, the KPD and the Politics of Class and Nation in Germany, 1922–1969

2005 ◽  
Vol 14 (3) ◽  
pp. 317-346 ◽  
Author(s):  
TIMOTHY S. BROWN
Keyword(s):  
Interwar Period ◽  
Third Reich ◽  
Radical Right ◽  
High Profile ◽  
Army Officer ◽  
Modern Germany ◽  
Before And After ◽  
The Third Reich ◽  
Relationship Of ◽  
The Relationship

This article examines the life and times of Richard Scheringer, an army officer and supporter of Adolf Hitler who became famous during the early 1930s for his high-profile conversion to communism. Known in the closing years of the Weimar Republic as a point-man for Communist efforts to win support from the radical right, Scheringer survived the Third Reich to become a leading figure in the postwar Communist Party. His well-documented but little-studied career, bridging critical caesurae of modern Germany history, highlights the unique political constellation of the interwar period, demonstrating fundamental continuities in the relationship of German communism to the nation before and after 1945.

Soil water dynamics after fire in a Portuguese shrubland

2006 ◽  
Vol 15 (1) ◽  
pp. 99 ◽  
Author(s):  
Joaquim S. Silva ◽  
Francisco C. Rego ◽  
Stefano Mazzoleni
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Plant Community ◽  
Root Distribution ◽  
Control Plot ◽  
The Other ◽  
Water Dynamics ◽  
Soil Water Dynamics ◽  
Surface Layers ◽  
Before And After

This paper presents a study where soil water content (SW) was measured before and after an experimental fire in a shrubland dominated by Erica scoparia L. in Portugal. Two plots were established: one was kept as a control plot and the other was burned by an experimental fire in June 2001. Measurements were taken before fire (2000), and after fire (2001, 2002, and 2003) at six depths down to 170 cm, from June to December. Measurements before fire allowed comparison of the two plots in terms of the SW differential, using 2000 as a reference. Results for 2001 showed that SW decreased less during the drying season (June–September) and increased more during the wetting season (October–December) in the burned plot than in the control plot. The magnitude of these effects decreased consistently in 2002 and 2003, especially at surface layers. The maximum gain of SW for the total profile in the burned plot was estimated as 105.5 mm in 2001, 70.2 mm in 2002, and 35.6 mm in 2003. The present paper discusses the mechanisms responsible for the increase in SW taking into account the characteristics of the plant community, including the root distribution, and the results of other studies.

RATIONALE FOR MONITORING GROUNDWATER LEVELS IN THE REHABILITATED PEATLANDS OF PRIPYAT POLESIE

2020 ◽  
pp. 33-43
Author(s):  
Olga N. Ratnicava ◽  
Irina P. Lisitsyna ◽  
Inna V. Аgeichik
Keyword(s):  
Field Studies ◽  
Natural State ◽  
Groundwater Levels ◽  
Discharge Water ◽  
Peat Deposits ◽  
Disturbed Areas ◽  
Key Points ◽  
Before And After ◽  
Vegetation Maps ◽  
Relationship Of

Based on studies of geomorphology, stratigraphy, hydrology, various maps of Polesie, zones of influence of amelioration canals, vegetation maps, modern satellite images, as well as field studies of peatlands of Pripyat Polesie, two independent drainage systems have been identified, with a network of amelioration canals that intensively discharge water into the rivers Stwiga and Ybort`. Maps of key points were built In GIS-format, on which five sites were laid in the field within the Mezhch and Neresnya peat deposits for further long-term monitoring of GWL parameters. The locations of the sensors installation are based on the relationship of bog phytocenoses with the average annual GWL values and the amplitude of their fluctuations. Analysis of the GWL parameters before and after environmental rehabilitation measures will allow assessing the effectiveness of planned measures in disturbed areas and obtaining new data on areas of peat deposits in their natural state.

Near-maximal voluntary hyperpnea and ventilatory muscle function

1984 ◽  
Vol 57 (6) ◽  
pp. 1742-1748 ◽  
Author(s):  
T. R. Bai ◽  
B. J. Rabinovitch ◽  
R. L. Pardy
Keyword(s):  
Muscle Function ◽  
Low Frequency ◽  
Normal Subjects ◽  
Pressure Time ◽  
Before And After ◽  
Expiratory Muscles ◽  
Four Levels ◽  
Frequency Relationship ◽  
Low Frequency Power ◽  
Relationship Of

Because of its potential relevance to heavy exercise we studied the ventilatory muscle function of five normal subjects before, during, and after shortterm near-maximal voluntary normocapnic hyperpnea. Measurements of pleural and abdominal pressures and diaphragm electromyogram (EMG) during hyperpnea and of maximum respiratory pressures before and after hyperpnea were made at four levels of ventilation: 76, 79, and 86% maximal voluntary ventilation (MVV) and at MVV. Measurements of pleural and abdominal pressures and diaphragm electromyogram (EMG) during hyperpnea and of maximum respiratory pressures before and after hyperpnea were made. The pressure-stimulation frequency relationship of the diaphragm obtained by unilateral transcutaneous phrenic nerve stimulation was studied in two subjects before and after hyperpnea. Decreases in maximal inspiratory (PImax) and transdiaphragmatic (Pdimax) strength were recorded posthyperpnea at 76 and 79% MVV. Decreases in the pressure-frequency curves of the diaphragm and the ratio of high-to-low frequency power of the diaphragm EMG occurred in association with decreases in Pdimax. Analysis of the pressure-time product (P X dt) for the inspiratory and expiratory muscles individually indicated the increasing contribution of expiratory muscle force to the attainment of higher levels of ventilation. Demonstrable ventilatory muscle fatigue may limit endurance at high levels of ventilation.

Carbon balance in relation to drying in four epiphytic mosses growing in different vertical ranges

1979 ◽  
Vol 57 (19) ◽  
pp. 1994-1998 ◽  
Author(s):  
Peter L. Tobiessen ◽  
Nancy G. Slack ◽  
Keith A. Mott
Keyword(s):  
Water Potential ◽  
Water Content ◽  
Carbon Balance ◽  
The Other ◽  
Moss Species ◽  
Relationship Of ◽  
The Relationship ◽  
Neckera Pennata ◽  
Lower Water Content ◽  
Photosynthesis And Respiration

The response of photosynthesis and respiration to drying was measured in four species of epiphytic mosses, Ulota crispa (Hedw.) Brid., Neckera pennata Hedw., Anomodon rugellii (C. Mull.) Keissl., and Plagiomnium cuspidatum (Hedw.) T. Kop., from habitats along a desiccation gradient. There was little difference among the mosses in these responses. The relationship of water content to water potential did differ among the mosses, with Plagiomnium, the facultative epiphyte, showing a typical response of more mesic species and the other three showing a more xeric response, i.e., water potential does not begin to fall steeply until a lower water content is reached in Ulota, Neckera, and Anomodon. Both photosynthesis and respiration in all four moss species were quite sensitive to moderate water stress.

Limitations to prediction of maximal oxygen intake

1964 ◽  
Vol 19 (5) ◽  
pp. 919-927 ◽  
Author(s):  
Loring B. Rowell ◽  
Henry L. Taylor ◽  
Yang Wang
Keyword(s):  
Metabolic Rate ◽  
Pulse Rate ◽  
Oxygen Intake ◽  
Physical Conditioning ◽  
Maximal Oxygen Intake ◽  
Before And After ◽  
Normal Men ◽  
Accuracy Of Prediction ◽  
Relationship Of ◽  
The Relationship

The predictability of maximal O2 intake (max Vo2) was studied in four groups of normal men, 18–24 years of age. Prediction of max Vo2 was made from pulse rate and Vo2 at a single submaximal workload at an ambient temperature of 78 F by use of the nomogram of Åstrand and Ryhming (1954) and underestimated actual max Vo2 by 27 ± 7% and 14 ± 7% in a sedentary group, before and after 2frac12–3 months of physical training, and by 5.6 ȁ 4% in a group of ten endurance athletes. Accuracy of prediction in all groups varied with approximation of pulse rate to 128 beats/min at 50% of max Vo2. Nonspecific stresses increased predictive errors in all groups. Constants b (slope) and A (intercept) in the regression equation Vo2 = bP – A (where P is pulse rate), were determined from Vo2 and pulse measured at four submaximal workloads requiring 13–28 ml O2/kg min. Prediction of max Vo2 by extrapolation of the slope to maximal pulse rate resulted in underestimation of 700–800 ml O2/min. Removal of 14% of circulating hemoglobin decreased max Vo2 by 4% but there was no change in pulse rates or predicted max Vo2. The relationship of RQ to V22 during work provided no reliable basis for prediction of max Vo2. exercise pulse rate, oxygen intake, relationship; pulse rate, oxygen intake relationship in exercise; metabolic rate, maximal aerobic prediction of; aerobic metabolic rate, maximal, prediction of; phlebotomy, effect on maximal oxygen intake, pulse rate; blood loss, effect on maximal oxygen intake, pulse rate; training, effect on maximal oxygen intake, pulse rates; physical conditioning, effect on maximal oxygen intake, pulse rates Submitted on October 4, 1963

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