scholarly journals LABORATORY EXPERIMENT ON CROSS-SHORE BARRIER SPIT EVOLUTION BY STORM DYNAMICS

2011 ◽  
Vol 1 (32) ◽  
pp. 32
Author(s):  
Nguyen Xuan Tinh ◽  
Magnus Larson ◽  
Chantal Donnelly ◽  
Hitoshi Tanaka

Every year there are many severe storms occurring around the world, in general, and in Japan, in particular. The occurrence of storms is expected to increase because of the global warming effects. An increasing wave height together with a rising mean water level during a storm create a high possibility for waves to overtop the beach crest causing a lot of sediment to be eroded to offshore areas or deposited in the inland direction. The study of the barrier island response to storms has therefore become very important in terms of sediment transport and beach morphology change, as well as damage to nearshore structures due to runup overwash and inundation overwash. However, changes in the beach profile and prevailing sediment transport mechanisms during a real event are difficult to obtain. Thus, laboratory studies are necessary to conduct. This study presents a laboratory experiment on the impact of storms on a sandy barrier islands. The main aim is to investigate the entire barrier island (or sand spit) response due to storm conditions considering the increase in water level due to storm surge. Also, further development of an analytical model for barrier profile change caused by runup overwash is presented and obtained results overall captured order-of-magnitude barrier face retreat and volume changes after the storm.

2021 ◽  
Vol 9 ◽  
Author(s):  
Qingyuan Yang ◽  
Tonghuan Liu ◽  
Jingjing Zhai ◽  
Xiekang Wang

In 2018, a flash flood occurred in the Zhongdu river, which lies in Yibin, Sichuan province of China. The flood caused many casualties and significant damage to people living nearby. Due to the difficulty in predicting where and when flash floods will happen, it is nearly impossible to set up monitors in advance to detect the floods in detail. Field investigations are usually carried out to study the flood propagation and disaster-causing mechanism after the flood’s happening. The field studies take the relic left by the flash flood to deduce the peak level, peak discharge, bed erosion, etc. and further revel the mechanism between water and sediment transport during the flash flood This kind of relic-based study will generate bigger errors in regions with great bed deformation. In this study, we come up with numerical simulations to investigate the flash flood that happened in the Zhongdu river. The simulations are based on two-dimensional shallow water models coupled with sediment transport and bed deformation models. Based on the real water level and discharge profile measured by a hydrometric station nearby, the numerical simulation reproduced the flash flood in the valley. The results show the flood coverage, water level variation, and velocity distribution during the flood. The simulation offers great help in studying the damage-causing process. Furthermore, simulations without considering sediment transport are also carried out to study the impact of bed erosion and sedimentation. The study proved that, without considering bed deformation, the flood may be greatly underestimated, and the sediment lying in the valley has great impact on flood power.


2018 ◽  
Vol 44 (2) ◽  
pp. 641 ◽  
Author(s):  
M. Béjar ◽  
D. Vericat ◽  
I. Nogales ◽  
F. Gallart ◽  
R.J. Batalla

This paper examines the effects of gravel mining on the suspended sediment transport in the Upper River Cinca (Central Pyrenees). Discharge, sediment transport and sediment grain-size distribution were measured, sampled and further determined in five monitoring sections along a 5-km river reach. Samples were taken at a section upstream from the mined area (i.e. reference section) and in four sections downstream (0, 200, 500 and 1500 meters). The results show that sediment concentrations downstream from the target site were up to one order of magnitude higher than in the reference section. Average concentrations during the impact were similar to those observed during floods, with maximum values attaining 6 g/l. Total load ranged from 2.2 to 17 Mg/day between sections; these values include the effects of the earth-moving works performed before the mining started. Concentrations at the lowermost section of the study reach were similar to those observed at the upstream reference section, suggesting that most of the suspended material was deposited in the channel. The transported material was coarse than that sampled under reference conditions; nevertheless, largest particles settled quickly, suggesting a selective transport downstream. This study constitutes a first step towards a better understanding of local sediment dynamics in rivers affected by maintenance works and related activities, such as gravel mining, and, overall, supports the comprehensive assessment of the effects of human actions on channel morphodynamics and the ecological functioning of mountain fluvial systems.


1979 ◽  
Vol 30 (4) ◽  
pp. 425 ◽  
Author(s):  
CA Ludington

Comparison of tidal records from One Tree Island and Heron Island, Southern Great Barrier Reef, shows that ponding of water inside the reef crest at One Tree Reef holds the lagoon water level near Mean Water Level for 5-6 h of each tide. The lagoon is therefore isolated from the surrounding ocean for half of each tidal cycle. The level of the tide with respect to the reef crest determines the impact of energy inputs on lagoon circulation. Details of the lagoon tidal curve are described and the implications for lagoon circulation, flushing and sedimentation are discussed.


GeroPsych ◽  
2011 ◽  
Vol 24 (3) ◽  
pp. 143-154 ◽  
Author(s):  
Elmar Gräßel ◽  
Raffaela Adabbo

The burden of caregivers has been intensively researched for the past 30 years and has resulted in a multitude of individual findings. This review illustrates the significance of the hypothetical construct of perceived burden for the further development and design of the homecare situation. Following explanations regarding the term informal caregiver, we derive the construct burden from its conceptual association with the transactional stress model of Lazarus and Folkman. Once the extent and characteristics of burden have been set forth, we then present the impact of perceived burden as the care situation. The question of predictors of burden will lead into the last section from which implications can be derived for homecare and relief of caregivers.


2019 ◽  
Vol 16 (6) ◽  
pp. 50-59
Author(s):  
O. P. Trubitsina ◽  
V. N. Bashkin

The article is devoted to the consideration of geopolitical challenges for the analysis of geoenvironmental risks (GERs) in the hydrocarbon development of the Arctic territory. Geopolitical risks (GPRs), like GERs, can be transformed into opposite external environment factors of oil and gas industry facilities in the form of additional opportunities or threats, which the authors identify in detail for each type of risk. This is necessary for further development of methodological base of expert methods for GER management in the context of the implementational proposed two-stage model of the GER analysis taking to account GPR for the improvement of effectiveness making decisions to ensure optimal operation of the facility oil and gas industry and minimize the impact on the environment in the geopolitical conditions of the Arctic.The authors declare no conflict of interest


Author(s):  
Valentyna Bohatyrets ◽  
Liubov Melnychuk ◽  
Yaroslav Zoriy

This paper seeks to investigate sustainable cross-border cooperation (CBC) as a distinctive model of interstate collaboration, embedded in the neighboring borderland regions of two or more countries. The focus of the research revolves around the establishment and further development of geostrategic, economic, cultural and scientific capacity of the Ukrainian-Romanian partnership as a fundamental construct in ensuring and strengthening the stability, security and cooperation in Europe. This research highlights Ukraine’s aspirations to establish, develop and diversify bilateral good-neighborly relations with Romania both regionally and internationally. The main objective is to elucidate Ukraine-Romania cross-border cooperation initiatives, inasmuch Ukraine-Romania CBC has been stirring up considerable interest in terms of its inexhaustible historical, cultural and spiritual ties. Furthermore, the similarity of the neighboring states’ strategic orientations grounds the basis for development and enhancement of Ukraine-Romania cooperation. The authors used desk research and quantitative research to conclude that Ukraine-Romania CBC has the impact not only on the EU and on Ukraine multi-vector foreign policy, but it also has the longer-term global consequences. In the light of the current reality, the idea of introducing and reinforcing the importance of Cross-Border Cooperation (CBC) sounds quite topical and relevant. This research considers a number of explanations for Ukraine-Romania Cross-Border Cooperation as a key element of the EU policy towards its neighbors. Besides, the subject of the research is considered from different perspectives in order to show the diversity and complexity of the Ukraine-Romania relations in view of the fact that sharing common borders we are presumed to find common solutions. As the research has demonstrated, the Ukraine-Romania cross border cooperation is a pivotal factor of boosting geostrategic, economic, political and cultural development for each participant country, largely depending on the neighboring countries’ cohesion and convergence. Significantly, there is an even stronger emphasis on the fact that while sharing the same borders, the countries share common interests and aspirations for economic thriving, cultural exchange, diplomatic ties and security, guaranteed by a legal framework. The findings of this study have a number of important implications for further development and enhancement of Ukraine-Romania cooperation. Accordingly, the research shows how imperative are the benefits of Romania as a strategic partner for outlining top priorities of Ukraine’s foreign policy.


2011 ◽  
Vol 14 (2) ◽  
Author(s):  
Thomas G Koch

Current estimates of obesity costs ignore the impact of future weight loss and gain, and may either over or underestimate economic consequences of weight loss. In light of this, I construct static and dynamic measures of medical costs associated with body mass index (BMI), to be balanced against the cost of one-time interventions. This study finds that ignoring the implications of weight loss and gain over time overstates the medical-cost savings of such interventions by an order of magnitude. When the relationship between spending and age is allowed to vary, weight-loss attempts appear to be cost-effective starting and ending with middle age. Some interventions recently proven to decrease weight may also be cost-effective.


2019 ◽  
Vol 29 (1) ◽  
pp. 273-287

The article examines the impact of the discourses concerning idleness and food on the formation of “production art” in the socio-political context of revolutionary Petrograd. The author argues that the development of the theory and practice of this early productionism was closely related to the larger political, social and ideological processes in the city. The Futurists, who were in the epicenter of Petrograd politics during the Civil War (1918–1921), were well acquainted with both of the discourses mentioned, and they contrasted the idleness of the old art with the dedicated labor of the “artist-proletarians” whom they valued as highly as people in the “traditional” working professions. And the search for the “right to exist” became the most important goal in a starving city dominated by the ideology of radical communism. The author departs from the prevailing approach in the literature, which links the artistic thought of the Futurists to Soviet ideology in its abstract, generalized form, and instead elucidates ideological influences in order to consider the early production texts in their immediate social and political contexts. The article shows that the basic concepts of production art (“artist-proletarian,” “creative labor,” etc.) were part of the mainstream trends in the politics of “red Petrograd.” The Futurists borrowed the popular notion of the “commune” for the title of their main newspaper but also worked with the Committees of the Rural Poor and with the state institutions for procurement and distribution. They took an active part in the Fine Art Department of Narkompros (People’s Commissariat of Education). The theory of production art was created under these conditions. The individualistic protest and “aesthetic terror” of pre-revolutionary Futurism had to be reconsidered, and new state policy measures were based on them. The harsh socio-economic context of war communism prompted artists to rethink their own role in the “impending commune.” Further development of these ideas led to the Constructivist movement and strongly influenced the extremely diverse trends within the “left art” of the 1920s.


Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 691
Author(s):  
Yugang Zhao ◽  
Zichao Zuo ◽  
Haibo Tang ◽  
Xin Zhang

Icing/snowing/frosting is ubiquitous in nature and industrial processes, and the accretion of ice mostly leads to catastrophic consequences. The existing understanding of icing is still limited, particularly for aircraft icing, where direct observation of the freezing dynamics is inaccessible. In this work, we investigate experimentally the impact and freezing of a water drop onto the supercooled substrate at extremely low vapor pressure, to mimic an aircraft passing through clouds at a relatively high altitude, engendering icing upon collisions with pendant drops. Special attention is focused on the ice coverage induced by an impinging drop, from the perimeter pointing outward along the radial direction. We observed two freezing regimes: (I) spread-recoil-freeze at the substrate temperature of Ts = −15.4 ± 0.2 °C and (II) spread (incomplete)-freeze at the substrate temperature of Ts = −22.1 ± 0.2 °C. The ice coverage is approximately one order of magnitude larger than the frozen drop itself, and counterintuitively, larger supercooling yields smaller ice coverage in the range of interest. We attribute the variation of ice coverage to the kinetics of vapor diffusion in the two regimes. This fundamental understanding benefits the design of new anti-icing technologies for aircraft.


Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 416
Author(s):  
Bwalya Malama ◽  
Devin Pritchard-Peterson ◽  
John J. Jasbinsek ◽  
Christopher Surfleet

We report the results of field and laboratory investigations of stream-aquifer interactions in a watershed along the California coast to assess the impact of groundwater pumping for irrigation on stream flows. The methods used include subsurface sediment sampling using direct-push drilling, laboratory permeability and particle size analyses of sediment, piezometer installation and instrumentation, stream discharge and stage monitoring, pumping tests for aquifer characterization, resistivity surveys, and long-term passive monitoring of stream stage and groundwater levels. Spectral analysis of long-term water level data was used to assess correlation between stream and groundwater level time series data. The investigations revealed the presence of a thin low permeability silt-clay aquitard unit between the main aquifer and the stream. This suggested a three layer conceptual model of the subsurface comprising unconfined and confined aquifers separated by an aquitard layer. This was broadly confirmed by resistivity surveys and pumping tests, the latter of which indicated the occurrence of leakage across the aquitard. The aquitard was determined to be 2–3 orders of magnitude less permeable than the aquifer, which is indicative of weak stream-aquifer connectivity and was confirmed by spectral analysis of stream-aquifer water level time series. The results illustrate the importance of site-specific investigations and suggest that even in systems where the stream is not in direct hydraulic contact with the producing aquifer, long-term stream depletion can occur due to leakage across low permeability units. This has implications for management of stream flows, groundwater abstraction, and water resources management during prolonged periods of drought.


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