Researches Concerning the Configuration of Geotextiles in the Execution of Regulatory Works in the Riverbeds

2020 ◽  
Vol 43 (3) ◽  
pp. 54-60
Author(s):  
Paul Vivian SION ◽  
◽  
Mihail LUCA ◽  
Mihaela AVRAM ◽  
◽  
...  
Keyword(s):  
Mode Of Action ◽  
Filling Material ◽  
Solid Flow ◽  
Research Results ◽  
The Stability ◽  
Alluvial Material ◽  
Sand And Gravel ◽  
Local Materials ◽  
Good Behaviour ◽  
Over Time

The paper deals with the behaviour at hydrodynamic action of the geotextiles used in carrying out the regularization and shore defence works located in riverbed. The geotextiles have lately presented applications for the execution of bottom thresholds, of the management dams in riverbed. Also, geotextiles have become an important component in the structure of river defence works on riverbeds. The research was carried out on the lower course of the Moldova River in the area of Pildesti, Neamţ County. The dynamic action of the floods, through the liquid and solid flows, influences the stability and the resistance over time of the constructions made from geotextiles. The researchers analysed the behaviour of the geo-bags made of polyester bags filled with local materials (sand and gravel stabilized with cement), used in the structure of the bottom thresholds, steering dams and in the shore defence works. The research results indicate a differentiated behaviour of the geo-bags depending on the location (in the water, or on the shore) and the mode of action of the water (dynamic or static). The action of the water, through the liquid and solid flow, degraded the structure of the geo-bags by breaking and emptying the filling material. The geo-bags showed a reduced resistance to the action of the alluvial material, especially when the dosage of cement indicated by the design was not achieved. The research highlighted the good behaviour of the geo-bags in the erosion phenomenon of the riverbed, when they were mulched on the erosion zones and ensured the continuity of the constructions in the riverbed (bottom thresholds and shore defences).

scholarly journals RESEARCHES ON BEHAVIOUR OF REGULATION WORKS LOCATED IN MORPHOLOGICALLY UNSTABLE RIVER BEDS

2019 ◽  
Vol 13 (2) ◽  
pp. 5-15
Author(s):  
Paul Vivian Sion ◽  
Mihail Luca ◽  
Ilie Logigan ◽  
Mihaela Avram
Keyword(s):  
Shore Protection ◽  
Research Results ◽  
Dynamic Action ◽  
Bed Erosion ◽  
River Bed ◽  
Static Water ◽  
The Stability ◽  
Alluvial Material ◽  
Sand And Gravel ◽  
Local Materials

The paper deals with the behaviour of geotextile regulation works on the dynamic action of floods in erodable river beds. Geotextiles have become an important component in the structure of river bed regulation and shore protection works. The dynamic action of floods, through liquid and solid flows, influences the stability and the resistance in time of geotextile constructions. The studies and researches were carried out on a sector of Moldova River between Soci and Pildeşti localities, on the territory of Iaşi and Neamţ counties. The researchers analysed the behaviour of geo-bagss made of polyester bags filled with local materials (generally sand and gravel) used for bottom sills, routing dikes and shore protection elements. The research results indicate a differentiated behaviour of geo-bagss according to their location (in water or on shore) and water action (dynamic or static). Water dynamic action has caused significant degradation of geo-bagss from bottom sills and routing dikes structures located in the river bed. Geo-bagss have low resistance to the alluvial material action (stone, trees) transported in the river bed during floods. The research highlighted the proper behaviour of geo-bagss during the river bed erosion phenomenon, when they moved and ensured the continuity of the bottom sills and their performance.

On the Robustness of Solution Strategy Classifications

2010 ◽  
Vol 31 (2) ◽  
pp. 68-73 ◽  
Author(s):  
María José Contreras ◽  
Víctor J. Rubio ◽  
Daniel Peña ◽  
José Santacreu
Keyword(s):  
Individual Differences ◽  
Study Strategies ◽  
Solution Strategy ◽  
Specific Test ◽  
Spatial Tasks ◽  
The Stability ◽  
Strategy Changes ◽  
Over Time

Individual differences in performance when solving spatial tasks can be partly explained by differences in the strategies used. Two main difficulties arise when studying such strategies: the identification of the strategy itself and the stability of the strategy over time. In the present study strategies were separated into three categories: segmented (analytic), holistic-feedback dependent, and holistic-planned, according to the procedure described by Peña, Contreras, Shih, and Santacreu (2008) . A group of individuals were evaluated twice on a 1-year test-retest basis. During the 1-year interval between tests, the participants were not able to prepare for the specific test used in this study or similar ones. It was found that 60% of the individuals kept the same strategy throughout the tests. When strategy changes did occur, they were usually due to a better strategy. These results prove the robustness of using strategy-based procedures for studying individual differences in spatial tasks.

On the Stability of Evaluative Conditioning Effects

2013 ◽  
Vol 44 (6) ◽  
pp. 380-389 ◽  
Author(s):  
Sabine Förderer ◽  
Christian Unkelbach
Keyword(s):  
Evaluative Conditioning ◽  
Indirect Measures ◽  
The Stability ◽  
Over Time

Evaluative conditioning (EC) refers to valence changes in neutral stimuli (CSs) through repeated pairing with liked or disliked stimuli (USs). The present study examined the stability of EC effects in the course of 1 week. We investigated how this stability depends on memory for US valence and US identity. We also investigated whether CSs evaluations occurring immediately after conditioning (i.e., evaluative consolidation) are necessary for stable EC effects. Participants showed stable EC effects on direct and indirect measures, independent of evaluations immediately after conditioning. EC effects depended on memory for US valence but not for US identity. And although memory decreased significantly over time, EC effects remained stable. These data suggest that evaluative consolidation is not necessary, and that conditioned preferences and attitudes might persist even when people do not remember the concrete source anymore.

scholarly journals Steady-state $$\dot{V}{\text{O}}_{2}$$ above MLSS: evidence that critical speed better represents maximal metabolic steady state in well-trained runners

2021 ◽  
Author(s):  
Rebekah J. Nixon ◽  
Sascha H. Kranen ◽  
Anni Vanhatalo ◽  
Andrew M. Jones
Keyword(s):  
Steady State ◽  
Critical Speed ◽  
Lactate Concentration ◽  
Practical Interest ◽  
Blood Lactate Concentration ◽  
Distance Runners ◽  
Severe Intensity ◽  
The Stability ◽  
Trained Runners ◽  
Over Time

AbstractThe metabolic boundary separating the heavy-intensity and severe-intensity exercise domains is of scientific and practical interest but there is controversy concerning whether the maximal lactate steady state (MLSS) or critical power (synonymous with critical speed, CS) better represents this boundary. We measured the running speeds at MLSS and CS and investigated their ability to discriminate speeds at which $$\dot{V}{\text{O}}_{2}$$ V ˙ O 2 was stable over time from speeds at which a steady-state $$\dot{V}{\text{O}}_{2}$$ V ˙ O 2 could not be established. Ten well-trained male distance runners completed 9–12 constant-speed treadmill tests, including 3–5 runs of up to 30-min duration for the assessment of MLSS and at least 4 runs performed to the limit of tolerance for assessment of CS. The running speeds at CS and MLSS were significantly different (16.4 ± 1.3 vs. 15.2 ± 0.9 km/h, respectively; P < 0.001). Blood lactate concentration was higher and increased with time at a speed 0.5 km/h higher than MLSS compared to MLSS (P < 0.01); however, pulmonary $$\dot{V}{\text{O}}_{2}$$ V ˙ O 2 did not change significantly between 10 and 30 min at either MLSS or MLSS + 0.5 km/h. In contrast, $$\dot{V}{\text{O}}_{2}$$ V ˙ O 2 increased significantly over time and reached $$\dot{V}{\text{O}}_{2\,\,\max }$$ V ˙ O 2 max at end-exercise at a speed ~ 0.4 km/h above CS (P < 0.05) but remained stable at a speed ~ 0.5 km/h below CS. The stability of $$\dot{V}{\text{O}}_{2}$$ V ˙ O 2 at a speed exceeding MLSS suggests that MLSS underestimates the maximal metabolic steady state. These results indicate that CS more closely represents the maximal metabolic steady state when the latter is appropriately defined according to the ability to stabilise pulmonary $$\dot{V}{\text{O}}_{2}$$ V ˙ O 2 .

scholarly journals Effect of Photoinitiator on Precursory Stability and Curing Depth of Thiol-Ene Clickable Gelatin

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1877
Author(s):  
Kai-Hung Yang ◽  
Gabriella Lindberg ◽  
Bram Soliman ◽  
Khoon Lim ◽  
Tim Woodfield ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Visible Light ◽  
Rheological Properties ◽  
Swelling Ratio ◽  
Sodium Persulfate ◽  
Photo Polymerization ◽  
Gelation Kinetics ◽  
The Stability ◽  
Over Time

Recent advances highlight the potential of photopolymerizable allylated gelatin (GelAGE) as a versatile hydrogel with highly tailorable properties. It is, however, unknown how different photoinitiating system affects the stability, gelation kinetics and curing depth of GelAGE. In this study, sol fraction, mass swelling ratio, mechanical properties, rheological properties, and curing depth were evaluated as a function of time with three photo-initiating systems: Irgacure 2959 (Ig2959; 320–500 nm), lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP; 320–500 nm), and ruthenium/sodium persulfate (Ru/SPS; 400–500 nm). Results demonstrated that GelAGE precursory solutions mixed with either Ig2959 or LAP remained stable over time while the Ru/SPS system enabled the onset of controllable redox polymerization without irradiation during pre-incubation. Photo-polymerization using the Ru/SPS system was significantly faster (<5 s) compared to both Ig2959 (70 s) and LAP (50 s). Plus, The Ru/SPS system was capable of polymerizing a thick construct (8.88 ± 0.94 mm), while Ig2959 (1.62 ± 0.49 mm) initiated hydrogels displayed poor penetration depth with LAP (7.38 ± 2.13 mm) in between. These results thus support the use of the visible light based Ru/SPS photo-initiator for constructs requiring rapid gelation and a good curing depth while Ig2959 or LAP can be applied for photo-polymerization of GelAGE materials requiring long-term incubation prior to application if UV is not a concern.

scholarly journals Influence of Crack Geometry on Dynamic Damage of Cracked Rock: Crack Number and Filling Material

2020 ◽  
Vol 11 (1) ◽  
pp. 250
Author(s):  
Feili Wang ◽  
Shuhong Wang ◽  
Zhanguo Xiu
Keyword(s):  
Energy Absorption ◽  
Split Hopkinson Pressure Bar ◽  
Mineral Exploration ◽  
Damage Variable ◽  
Filling Material ◽  
Hopkinson Pressure Bar ◽  
Filling Materials ◽  
The Stability ◽  
Pressure Bar ◽  
Dynamic Damage

The dynamic damage of cracked rock threatens the stability of rock structures in rock engineering applications such as underground excavation, mineral exploration and rock slopes. In this study, the dynamic damage of cracked rock with different spatial geometry was investigated in an experimental method. Approximately 54 sandstone specimens with different numbers of joints and different filling materials were tested using the split Hopkinson pressure bar (SHPB) apparatus. The energy absorption in this process was analyzed, and the damage variable was obtained. The experimental results revealed that the dynamic damage of cracked rock is obviously influenced by the number of cracks; the larger the number, the higher the energy absorption and the bigger the dynamic damage variable. Moreover, it was observed from the dynamic compressive experiments that the energy absorption and the dynamic variable decreased with the strength and cohesion of the filling material, indicating that the filling material of crack has considerate influence on the dynamic damage of cracked rock.

The Stability Control of Soft Soil Foundations of Urban Roads According to the Surface Subsidence Monitoring Data

2013 ◽  
Vol 859 ◽  
pp. 222-227
Author(s):  
Hong Jun Liu ◽  
Jin Hua Tan ◽  
Xue Wen Su ◽  
Hao Wu
Keyword(s):  
Soft Soil ◽  
Stability Control ◽  
Surface Subsidence ◽  
Monitoring Data ◽  
Research Results ◽  
The Road ◽  
Future Design ◽  
Left And Right ◽  
Soil Foundation ◽  
The Stability

Two typical monitoring sections are selected for obtaining the change law of the surface subsidence and the settlement after construction of soft soil foundations, and determining the reasonable unloading time. The research results show that the surface settlement rate is large during the filling stage, the rate decreases after the loading and gradually stabilized. The embankment midline settlement is larger than the settlement of the road shoulder which is concluded from the fact that the subsidence of the middle settlement plate is larger than those of the left and right plate. The surface subsidence rate is less than 5mm per month during the two month before unloading according to the data in the tables. The settlement after construction presumed from the middle plate is more significantly larger than that of left and right sides, hence, as the unloading basis of preloading drainage method in soft soil foundation treatment the settlement after construction which is calculated from the midline monitoring data of the road is appropriate. After 6 months the calculated post-construction settlements of the two sections are in the scope of the design requirement since they decrease with preloading time. The reliable basis is provided for the future design and construction of soft foundation in this area through the research results.

An Analytical Study of the Folk Musical Instruments of Meghalaya

2021 ◽  
Vol 66 (1) ◽  
pp. 23-38
Author(s):  
Joyanta Sarkar ◽  
Anil Rai
Keyword(s):  
20Th Century ◽  
Folk Music ◽  
Analytical Study ◽  
Musical Instrument ◽  
Folk Songs ◽  
Musical Instruments ◽  
Indian State ◽  
Material Benefits ◽  
Local Materials ◽  
Over Time

"Meghalaya is a richly inhabited Indian state. Drums, flutes of bamboo and hand-held small cymbals are a common ensemble. The advent of Christianity in the middle of the 20th century marked the start of a decline in tribal popular music. Over time, Meghalaya’s music scene has evolved, attracting many talented artists and bands from both traditional and not-so traditional genres. Any of the most recent Meghalaya musicians and bands is: The Plague Throat, Kerios Wahlang, Cryptographik Street Poets, etc., Soulmate, Lou Majaw, and Snow White. Meghalaya’s music is characterised by traditional instruments and folk songs. The Musical Instruments of Meghalaya are made from local materials. Meghalayan people honour powerful natural forces and aim to pacify animistic spirits and local gods. The instruments are made of bamboo, flesh, wood, and animal horn. Any one of these musical instruments is considered to have the ability to offer material benefits. The Meghalaya musical instrument is an essential part of traditional folk music in the region. In this article, we offer an overview of the folk musical instruments of Meghalaya. Keywords: Idiophone, Aerophone, Chordophone, Membranophone, Trumpet. "

Income Elasticities for State Tax Revenues: Techniques of Estimation and Their Usefulness for Forecasting

1973 ◽  
Vol 1 (4) ◽  
pp. 409-425 ◽  
Author(s):  
Robert E. Berney ◽  
Bernard H. Frerichs
Keyword(s):  
Time Series ◽  
Regression Analysis ◽  
Income Elasticity ◽  
Income Elasticities ◽  
Tax Revenues ◽  
State Tax ◽  
The Stability ◽  
Revenue Estimation ◽  
Theoretical Foundations ◽  
Over Time

The concept of income elasticity of tax revenues has been used in numerous studies with little concern about its theoretical foundations. Income elasticities have also been used for revenue estimation with limited concern about stability over time or about the accuracy of the forecasts. This paper explores the development of the tax elasticity measure and, using revenue data from Washington, compares year-to-year elasticity measures with those established by regression analysis. The length of the time series is varied to check on the stability of the coefficients. Finally, the elasticities are used to predict revenues for three years to check on their accuracy for revenue estimation.

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