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In this study, the amount of flood risk reduction due to applying one of natural flood management measures, in alluvial fans, was investigated. Usually, flood management is done by common structural and nonstructural methods, which are expensive and short-lived. Flood damage reduction and using more stable and flexible solutions for flood management, have been received more attention from researchers in recent years. Using natural flood management (NFM) is considered stable methods of flood management, and in this study by presenting a natural solution in the form of increasing the length of the river by creating a meander, to investigate its effect on the expected flood damage compared to the base mode is paid. The method of conducting this study is based on modeling, which uses three models: HEC-HMS, HEC-RAS 2D and ArcMap. The study area is Abbakhsha River catchment located in Bardsir city, Kerman province, with an area of 1136 square kilometers, has the state of an alluvial fan that numerous floods have occurred. Topography, precipitation and discharge are the most important data required for this study. According to the results of this research, creating a meander in the river reduces the expected annual damage (EAD) by 15.5%. The results of this research can be effective in the planning and policy making of optimal flood management solutions in the region. [ABSTRACT FROM AUTHOR]

Entering the East China Sea (ECS) through the east of Taiwan, the Kuroshio flows northeastward, with its pathway confined along the continental slope of the Okinawa Trough. Four 75 kHz Acoustic Doppler Current Profilers (ADCPs) were deployed over a 3-year period (June 2020–June 2023), with two placed across the typical path of the Kuroshio in each of the two latitudinal bands, to examine the relationship of current variability between upstream and downstream in the ECS. The along-path and cross-path velocities from the four ADCPs show dominant intraseasonal variability with a period of 8–32 days. Within this frequency band, current velocities exhibit a strong relationship when the upstream precedes the downstream by 6 days. The amplitude of this lagged co-variability tends to be larger from May to August, with an increase in along-path speed variability of up to about 24% at approximately 250 m depth for the onshore sites and an increase in cross-path speed variability of up to about 22% within the 200–300 m layer for the offshore sites. The intraseasonal variability of the sea level anomaly associated with this observed co-variability displays the Kuroshio meanders along its path, propagating northeastward at a speed of about 14.8 km/day. These results provide observational evidence of the Kuroshio meander and its propagation in the ECS, characterized by subsurface intensification during the warm season.

The soils and vegetation of Arctic floodplains are vulnerable to global warming because, in addition to climate change, they are affected by the changing hydrological regime of rivers. However, for river floodplains in large Arctic regions, such as the Yamalo-Gydan ecoregion, even descriptive field studies are still very incomplete. Therefore we studied the vegetation and soils of the floodplain of the small Tenyakha River in the south of the Gydan Peninsula. Two types of floodplain are described. The first type is represented by a floodplain on channel slopes. The second is a meander with ridges and depressions in between. Plant communities of the first type of floodplain have a higher diversity of higher plants than communities of the second type. Plant communities of microtopographic depressions and concave slopes have a lower diversity of vascular plants. The soil-forming deposits are predominantly sandy. According to the WRB, almost all the soils studied are classified as Fluvisols, except for one, classified as Arenosol, which is present in modern aeolian deposits on the floodplain ridge. All soils within two meters of the surface contain permafrost. There are soils with a humus horizon more than 20 cm thick (Gleyic Orthofluvic Fluvisol (Epiarenic, Endosiltic, Ochric)). The Munsell value of these soils is the same as that of the humus horizons of the zonal soils of the southern taiga and subtaiga. We have not detected a distinct effect of climate change on the soils. Further research is needed to confirm this.

The symbolism of the spiral and the meander is well known from the ornaments on Minoan and Mycenaean artifacts, while the roots of this symbolism can be traced chronologically much deeper than these cultures and have been fixed since the Paleolithic era. This symbolism has always been of interest to researchers, as it is evidence of the archetypal use of these symbols in the process of formation of religious views of Homo sapiens from the Paleolithic era to the present. In the proposed work, possible ways of formation of this symbolism are considered on the basis of the trajectory of the Sun's movement above the horizon line observed by the priests of various cultures and the represented path of the Sun's movement below the horizon line.

In this article, we investigate meandric systems having one shallow side: the arch configuration on that side has depth at most two. This class of meandric systems was introduced and extensively examined by I. P. Goulden, A. Nica, and D. Puder [Int. Math. Res. Not. IMRN 2020 (2020), 983-1034]. Shallow arch configurations are in bijection with the set of interval partitions. We study meandric systems by using moment-cumulant transforms for noncrossing and interval partitions, corresponding to the notions of free and Boolean independence, respectively, in non-commutative probability. We obtain formulas for the generating series of different classes of meandric systems with one shallow side by explicitly enumerating the simpler, irreducible objects. In addition, we propose random matrix models for the corresponding meandric polynomials, which can be described in the language of quantum information theory, in particular that of quantum channels. [ABSTRACT FROM AUTHOR]

In the case of flooding in rivers, river regulation structures are important since scours occur on the outer meander due to high flow velocities. In this study, 2-array submerged vane structures were investigated which is a new method in the meandering part of open channels, both laboratory and numerically with an open channel flow discharge of 20 L/s. Open channel flow experiments were carried out by using a submerged vane and without a vane. The flow velocity results of the computational fluid dynamics (CFD) models were compared to the experimental results and the results were found compatible. The flow velocities were investigated along with depth using the CFD and found that the maximum velocity was reduced by 22–27% along the depth. In the outer meander, the 2-array submerged vane with a 6-vane structure was found to affect the flow velocity by 26–29% in the region behind the vane.

This paper proposes a hexagonal meander-shaped wideband electronically reconfigurable transmitarray (HMRTA) at Ku band for satellite communications and radar applications. The proposed transmitarray offers high gain, low profile, and wideband characteristics with beam-scanning and beam-forming features. The cascaded structure is a low-profile and compact transmitarray. The transmitter (Tx) layer has an angular hexagonal patch with a meandered shape and resonating parasitic patches to enhance the bandwidth. The receiver (Rx) layer comprises a two-part hexagonal receiver patch and a dual ring impedance-matching receiver layer. The current reversal phenomena have executed the 180° phase shift by integrating two diodes in opposite directions. The measured results of a unit cell achieve a minimum insertion loss of 0.86 dB and 0.92 dB for state I and state II. The maximum insertion loss is 2.58 dB from 14.12 GHz to 18.02 GHz and is about 24.83% at 16.5 GHz. The full-wave simulations of a 20 × 20 space-fed reconfigurable transmitarray were performed. Good radiation patterns at all scanning angles of two principal planes are achieved, and the cross-polarization level remains less than −20 dB. The simulated 3 dB gain fluctuation bandwidth of the array is 15.85~18.35 GHz, and the wideband characteristics are verified. The simulation results show that the array can perform beam scanning ±60° in the elevation (y-z) plane and obtain the beam-scanning characteristics for ±60° in the Azimuth (x-z) plane. [ABSTRACT FROM AUTHOR]

Subject and Purpose. The paper presents results of numerical modeling and experimental studies of a disk-shaped microstrip antenna involving ‘meander’ type slotted inhomogeneities. The work has been aimed at optimizing the operating range of the antenna and matching it to external circuits through the use of additional structural elements and appropriate feeding techniques. Methods and Methodology. The design features a circular disk-shaped microstrip resonator containing within its plane groups of slotted inhomogeneities which form a segmented meander line, with the segments oriented relative one another at an angle of 120°. The antenna could be fed through a segment of a screened coplanar line. The location of the screening plane of the coplanar line, as well as its dimensions, were variable. Numerical simulation was carried out within the ‘semi-open resonator’ technique using the finite element method. The degree of optimization of the operating range was estimated, based on analyzing spectral characteristics of the antenna, for a variety of its geometric parameters, and the magnitude of the return loss over a given frequency range. Measurements of the VSWR were carried out with reflectometers. Results. Frequency and power characteristics of a monopole, disk-shaped microstrip antenna have been analyzed and optimized over a wide frequency range. Mechanical dimensions of the additional shielding plane and location thereof have been identified as factors having significant influence upon the frequency-dependent, polarizational and power characteristics of the antenna. Conclusions. The operating frequency range, spectral and power characteristics of a monopole, disk-shaped microstrip antenna have been studied both theoretically and experimentally. Numerical simulations were carried out with the use of the fi nite element method. Experimental studies of the frequency characteristics were performed using reflectometry techniques. The antenna considered can find practical application over a wide frequency range, either as a single radiating element in a device or system, or a constituent part of an antenna array.

Regulation structures such as submerged vane are needed to reduce and eliminate environmental damage due to increased flooding in rivers. In particular, scours on the outer bank due to increased flow velocities cause the river bed to change and deteriorate. In this study, the effect on flow velocities was investigated experimentally by using 3-array submerged vane structures in areas close to the outer bank. The experimental vane results were performed in the open channel setup. The Computational Fluid Dynamics (CFD) results obtained with the numerical model were also verified and compared with experimental results. It has been observed that the CFD model gives results close to the real experimental results. The standard-based k-ε model was used as the turbulence model. In the outer meander, the 3-array submerged vane with a 3-vane structure was found to affect the flow velocity by 16–27% in the region behind the vane. The flow velocities were investigated along with depth using the CFD and found that the mean velocity was reduced by 14–21% along the depth. It is also recommended that submerged vane structures can be applied as an effective method in reducing flow velocities and directing flows. [ABSTRACT FROM AUTHOR]

Aim. In this work, the main aim was a retrospective analysis of the geo‐ecological state and problems of natural territorial complexes (NTC) of the valley of the plains area of the Kuma River in the context of hydrological and morphological dynamics for the period from the 18th century to the present.Material and Methods. The paper analyses the state of the landscape’s natural components in the region, for which topographic, sectoral and cadastral maps, digital relief model, satellite images were used. Openly available data of ministries, departments, archival and stock materials were used. The degree of anthropogenic transformation of the natural‐territorial complexes was calculated based on the coefficient of ecological stability of landscapes.Result. Using the example of the plains area of the Kuma River for the period of the 18th‐21st centuries, the geo‐ecological features of valley NTC were analysed. Studies have shown that at the present stage meandering remains an important condition for land use in the Kuma River valley in terms of both agricultural land and residential areas. Cartographic schemes of land use of a modelled plot in the valley of the Kuma River were constructed, allowing the assessment of the efficiency of the economic use of the fields of oxbow lakes.Conclusion. For the last two hundred years, valley NTC have remained significant for settlement purposes and related economic activities. The modern meandering belt together with the fields of the older such features create special environment forming conditions for the functioning of the stabilising components of the landscape, floodplain forest being a basic integral factor in the preservation of regional biodiversity. It is recommended that when organising the sustainable use of the land resources of river valleys for the purposes of territorial planning, the regional features of placement of meanders and oxbow lakes be taken into account.

Meandering rivers are among the most dynamic Earth-surface systems, which generally appear in fertile valleys, the most valuable lands for agriculture and human settlement. Landsat time series and morphological parameters are complementary tools for exploring river dynamics. Karun River is the most effluent and largest meandering river in Iran, which keeps the Karun's basin economy, agriculture, and industrial sections alive; hence, investigating morphological changes in this river is essential. The morphological characteristics of Karun have undergone considerable changes over time due to several tectonic, hydrological, hydraulic, and anthropogenic factors. This study has identified and analyzed morphological changes in Karun River using a time series of Landsat imagery from 1985–2015. On that basis, morphological dynamics, including the river's active channel width, meander's neck length, water flow length, sinuosity index, and Cornice central angle, were quantitatively investigated. Additionally, the correlation between the stream power and morphological factors was explored using the data adopted from the hydrometric stations. The results show that the dominant pattern of the Karun River, due to the sinuosity coefficient, is meandering, and the majority of the river falls in the category of developed meander rivers. Moreover, the number of arteries reduced in an anabranch pattern, and the river has been migrating towards the downstream and eastern sides since 1985. This phenomenon disposes a change in the future that can be hazardous to the croplands and demands specific considerations for catchment management. [ABSTRACT FROM AUTHOR]

A spur dike is mainly constructed as a river-training structure and is primarily used to prevent bank erosion. The restriction to flow caused by the construction of a spur dike promotes local scour around the structure. In the case of a dike placed in a channel bend, the scour becomes more aggressive. The literature review found that the research work related to local scour around a spur dike located in a meandering channel is very limited or minimal. Therefore, an experimental investigation was conducted to study the local scour process around a T-shaped spur dike placed at different locations along the outer bank (or concave) of a reverse-meandering channel. Non-dimensionalized empirical equations for temporal and maximum local scour depth were developed as the function of the Froude number of approach flow and spur dike location. It is observed that local scour around the dike increases with the increase in Froude number and location in the meander (measured from the entry to meander). The formulation for the maximum scour depth was further evaluated with the experimental data related to the 180° bend, from literature, and it was found that the proposed equation's application is very much limited. HIGHLIGHTS Scour process is studied around T-shaped spur dike located in reverse meandering channel.; Various factors affecting scour such as Froude number of approach flow, time of scouring, and spur dike have been evaluated and studied in detail.; Empirical relations have been developed to estimate temporal and maximum scour depth.; Some experimental observations regarding flow pattern and bed topography has been discussed.;

الملخص: إن زخرفة المتاهة والتي تعني المياندر، أو كما يطلق عليها البعض الزخارف المتعرجة: هى نوع من الزخارف الهندسية التي ظهرت في الفن المصري القديم، كما أنها ظهرت في الفن الإغريقي والروماني (الفترة الكلاسيكية) بأنواع وأشكال متعددة. أما زخرفة المتاهة (المياندر) في العمارة الإسلامية فلم ترصده دراسة متخصصة على الرغم من ظهور هذه الزخرفة على العمائر الإسلامية منذ العصر الأموي في بلاد الشام، وفي مصر وجدت الزخرفة على التحف الفنية والعمائر التي تُنسب إلى الحقبة القبطية، واستمر استخدامها في العصر (الفاطمي، الأيوبي والمملوكي) كإطارات تحدد الزخارف الرئيسة بالتحف أو داخل أشكال هندسية تفصل بينها بنفس الأسلوب الذي وجد على العمائر والتحف السلجوقية، وقد وجدت هذه الزخرفة على واجهات المنازل بمدينة رشيد وذلك منذ القرن 12ه/ 18م، وانتشر استخدامها منذ عصر محمد علي وأسرته مع الابتكار والتفنن في بعض الأحيان، والتنوع في المواد التي نفذت بها الزخرفة؛ لذا فقد تم تتبع هذه الزخرفة على العمائر الإسلامية والاستعانة ببعض التحف الفنية كنماذج لتوضيح طرق تنفيذ هذه الزخرفة وتتبع تطورها في الفنون الإسلامية. Abstract: Meander (meandros) is a kind of geometric decorations that appeared in the Ancient Egyptian art. It was also used in the Greek and Roman arts in various types and forms. Meander has not been investigated in the Islamic architecture, although it was utilized in the Islamic buildings in the Levant during the Umayyad era. It was also used in the artifacts and buildings of the Coptic era and was assumed in the (Fatimid, Ayyubid, and Mamluk) eras as a border or interior of the geometric forms following the same style of the Seljuk buildings and artifacts. It was implemented on the façades of houses in Rosetta in the 12th A.H. / 18th A.D. century. Furthermore, it spread and evolved in the reign of Muhammad Ali and his dynasty, when various materials were used for decoration. The present study explores this motif on the Islamic buildings and artifacts, which acted as models for illustrating its implementation and development in the Islamic arts.

Abstract Aim Our objective was to describe the structure and spatial patterns of the zooplankton community in a small Brazilian river system (Paranaíba River sub-basin) and evaluate the role of an oxbow lake in the dynamics of this community. Methods Zooplankton samples were collected from sites located in an oxbow lake and the Aporé River bed during the rainy and dry seasons. We collected these samples from the surface and bottom levels of two different zones (littoral and channel). For each hydrological season, analysis of variance was conducted to determine the differences in species richness and abundance of zooplankton among different sites (longitudinal), zones (lateral), and depths (vertical). Cluster analysis was performed to assess the similarity in species composition. In addition, a canonical correspondence analysis was used to select the environmental variables that best explained the variation in zooplankton abundance data. Results We recorded 152 species: 70 rotifers, 53 testate amoebae, 20 cladocerans, and 9 copepods. We observed changes in the species richness and abundance of zooplankton along the longitudinal axis of the river in both the rainy and dry seasons. However, we did not detect any lateral or vertical changes in these attributes. Cluster analysis also indicated that the greatest differences in species composition were in the longitudinal axis of the river. The longitudinal variability of zooplankton was mainly associated with the influence of an upstream oxbow lake, as well as the changes in water flow velocity, turbidity, and concentrations of suspended solids downstream. Conclusions Our results demonstrate the importance of a heterogeneity of hydrological characteristics as a structuring factor of the zooplankton community in the Aporé River. Thus, we highlight the relevance of actions to protect and maintain the natural characteristics of these environments.

Natural wrinkling of metal films on silicone substrates can appear by means of the metal sputtering process and can be described by the continuous elastic theory and non-linear wrinkling model. Here, we report the fabrication technology and behavior of thin freestanding Polydimethylsiloxane (PDMS) membranes equipped with thermo-electric meander-shaped elements. The Cr/Au wires were obtained on the silicone substrate by magnetron sputtering. We observe wrinkle formation and suppose furrows appear once PDMS returns to its initial state after the thermo-mechanical expansion during sputtering. Although the substrate thickness is usually a negligible parameter in the theory of wrinkle formation, we found that the self-assembled wrinkling architecture of the PDMS/Cr/Au varies due to the membrane thickness of 20 µm and 40 µm PDMS. We also demonstrate that the wrinkling of the meander wire affects its length, and it causes a 2.7 times higher resistance compared to a calculated value. Therefore, we investigate the influence of the PDMS mixing ratio on the thermo-electric meander-shaped elements. For the stiffer PDMS with a mixing ratio of 10:4, the resistance due to wrinkle amplitude alterations is 25% higher compared to the PDMS of ratio 10:1. Additionally, we observe and describe a thermo-mechanically induced motion behavior of the meander wires on completely freestanding PDMS membrane under applied current. These results can improve the understanding of wrinkle formation, which influences thermo-electric characteristics and may promote the integration of this technology in applications.

The morphological evolution of the fluvial relief in the lowland areas is determined by the dynamic of the lateral channel migration process. River meandering and lateral channel migration represent continuous, dynamic and complex processes, which intensity modifies alluvial plains. Accordingly, it is a current topic observed from the domain of various scientific disciplines and practices, including the geographical aspect of the study. Directly or indirectly, variations of natural and anthropogenic processes affect changes in the lateral migration intensity, which is later manifested through permanent consequences for the environment. The aim of this paper is to investigate the process of lateral channel migration, through the review and interpretation of theoretical and methodological concepts and results of contemporary scientific literature. In this paper, on specific sections of the South Morava River (Serbia), the values of maximum lateral migration over different time periods are determined. Three representative river sectors were singled out, spatial and temporal dynamic was determined, while the process of lateral channel migration was presented quantitatively and graphically. Based on the obtained data, a comparative analysis showed significant riverbank changes for the observed meanders, within the period 1924-2020. Special emphasis is on the analysis of the lateral channel migration in the last decade of the mentioned period. The obtained results can be further used in order to develop and implement plans of water and land management, environmental protection and socio-economic development strategies. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 176017]

Morphological changes in rivers lead to serious damages, including changes in the width of the waterways, changes in the drainage plan, erosion and sedimentation of the bed and banks, structural failure and loss of valuable land. A two-dimensional numerical model called CCHE2D was used to simulate the effect of the flow pattern on the river bed changes in the reach of the natural floodplain of the Kor River between the Abbas Abad Bridge and the Dorudzan Bridge, the Province of Fars. The topographical maps of the study area, the geometry of the model, and the computational grid with different dimensions were prepared. Based on the measured flow parameters, a two-dimensional hydrodynamic model of the mean depth, performance and results such as the changes in depth, flow velocity, secondary flow and shear stress were extracted. Finally, two data sets of the RMSE and MAPE were compared using the numerical model simulation versus the collected data. The results showed that this model had a good accuracy in predicting the flow parameter values, ​​and the simulated data were similar to those obtained from field measurements. The results of changes in the flow pattern as an effective indicator in predicting the hydraulic behavior and hydrodynamics showed that by correcting the path and removing the bends in the clay meadows of the Kor River by straightening the meanders, the heavy erosion of meander most agricultural land will be prevented. It must be emphasized that straightening the waterway entails its lining with erosion-resisting materials. It can be seen that using the computational fluid dynamics for modeling the stream bed variations brings researchers closer to a more general predictions for governing the processes in riverine plains. Also, the CCHE2D model has a good ability to predict changes in meandering rivers.

The Shirley Basin is a small asymmetric synclinal structure located in northern Carbon County, Wyoming approximately 65 km (40 miles) south of Casper, Wyoming, USA. The basin formed during the Laramide orogeny of the Late Cretaceous to Early Tertiary (78–49 Ma) and contains economically significant uranium deposits. The underlying Cretaceous units form an angular unconformity with the overlying Tertiary units that represents a paleotopographic erosional surface characterized by stream channels and overbank deposits of interbedded sand and clay with some organic detritus. Furthermore, the Cretaceous shales function as the lower confining unit/aquitard for in-situ recovery (ISR) uranium mining, and the overlying Tertiary sandstones host the uranium mineralization. This study maps the K/T boundary in greater detail than previous studies and identifies paleotopographic features that influence sedimentary environments and structures that favor uranium mineralization. Using a larger study region and thousands of historical wells and associated electric logs not available to previous studies, this research identifies unit boundaries and enters them into Golden Software’s Surfer and Esri’s ArcGIS to construct a detailed structure contour map on the K/T surface. The map delineates paleotopography such as hills and river channels, with the latter showing a strong spatial association with uranium mineralization. Geologists can use these maps to identify thicker host sands and fluvial features which enhance uranium mineralization. Mining companies can reduce operational and exploration costs by drilling in these more favorable areas to efficiently delineate the ore body geometry and develop more accurate mine unit designs that will maximize uranium recovery.

The streams of rivers are extremely complex in nature. Rivers are beneficial for natural vegetation, animals, living organisms and human communities. The river provides the possibility of drinking water and irrigation of agricultural fields. Rivers are considered as active land cultivators with erosion and sedimentation. Some of the negative effects of rivers such as floods are considered as a natural disaster. Such natural disasters have been shown when the river by anthropogenic activities by changing the shape of the river and arched their plans change. Meandering parts of the rivers are vulnerable to floods. Therefore, river studies are very important in terms of hydraulic characteristics, sediment, width to depth ratio, morphology and arched plan. Kaleibar Chai basin has located on the North West of the country. This research pays attention to the arcuate plan of Kaleibar River from the city of Kaleibar to Jananloo village (one of the branches of Aras River). The study region is part of Kaleibar Chai River with 72 km of length. The channel consists of right, waving, meandering, and braided patterns. The study of horizontal plan of the river in relation to different active processes shows the mutual relationship between hydrological parameters and the materials in the river. The continual changes in sinuosity index in the channel are indicators of variations in the river behavior. For doing this research we used Google Earth and DEM 10m images. The river was divided into 4 openings in which topographic conditions were considered. The river sinuosity index was calculated for all 4 openings in GIS software under the formula: TSI= . In this equation TCI is topographic sinuosity index, CL is the length of the river channel, Al is the aerial length of the beginning and ending part of the channel. The maximum sinuosity index for different lengths of the Kaleibar Chai River was estimated at 1.05 to 1.83. The heterogeneity of bed materials causes erosion and deposition on the river bed of Kaleibar Chai. Erosion and depositional processes occur in the area during the spring and fall floods. The variety of materials and their sizes cause erosion and the collapse of the brinks and the loop in sinuosity index, which finally lead to channel changes. The study of sinuosity index and the identification of rivers patterns help ease the planning procedure

River morphology is the science of knowing the river system in terms of general shape, dimensions and characteristics of hydraulic geometry, the direction and longitudinal profile of the bed, as well as the mechanism of its changes. Morphological study is needed to understand the current conditions and the potential for future river changes in the future, and perhaps it is only that it is possible to predict the natural behavior of the river in relation to natural changes or actions arising from the implementation of various river engineering projects. Most of the water structures such as dams, bridges and pumping stations are located in the margins of rivers that can be affected by changes in river morphology. Application of remote sensing images and Geographical Information Systems (GIS) can be effective to achieve a more accurate analysis. Today, land use change, vegetation cover and morphological changes of rivers in River Engineering Sciences are of great importance using remote sensing and GIS techniques. Yamani and Sharafi (2012) showed that morphological changes and erosion of the Herrud River from the upstream downstream has decreased. Also, the geological and lithological structures of the bed and river bank are the most important factors in the stability of the bed. Yousefi et al. (2013). In order to investigate the changes of some Meander parameters in the Karun River using Landsat satellite images, morphological parameters of 20 Meanders were determined in an interval of 128 km length of Karun River after the preparation of a land use map for each period. Rashidi et al. (2016) studied geomorphologic changes of the Karoon River bed and its causes from 1334 to 1391. The results indicate significant changes in river morphology including latitudes, meanders, and sedimentary islands due to the decrease in the discharge, the construction of multiple bridges along the path, geological factors and vegetation. The study of past research shows that the study of river morphology in other countries has also been of great importance. Clerici et al. (2015) examined the morphological changes of the Taro River in Italy over the last two centuries and showed that human beings have made the most of the changes for agricultural and industrial purposes, the construction of multiple bridges and casualization. According to the research, the main issue of this research is to investigate the changes in the Gamasiab River, which in recent years has threatened the communication paths, landscapes and, in summary, human structures along the river banks. Therefore, the objective is to study the variation of the morphology of the Gamasiab river from the point of view of the central radius and angle, and the number of archs during the 1990-2013 period, and the extent of the development of the piers.

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The province of Tucumán, Argentina has a dense fluvial network, with rivers that have shown, over the last 45 years, complex and dynamic behaviors, as a result of high streamflows. In the upper basins, located in the mountainous zone and piedmont, diverse anthropic activities developed in contrasted reliefs and erosive slopes. The increase in rainfall recorded in the region since 1970 has increased both the erosive and depositional processes in the alluvial plain by modifying the design of the channels, with important consequences on the farmlands. In this paper, the Seco river bed is analyzed thoroughly. The Seco river is born on the eastern slope of the Aconquija mountains, runs through the piedmont and the alluvial plain in a west-east direction, and finally discharges into the Salí river, the main river bed of the fluvial network of the province. The main objective of this work is an analysis of meander morphology along 6.28 km of the Seco river for the period 1972 to 2017. The main parameters analyzed were the sinuosity of the channel, and meander cuts by overflow (chute cutoff) and by tangency (neck cutoff). These processes have accelerated the loss of agricultural land by lateral erosion on the river ravines, which are composed of fluvial-alluvial sediments, the parental materials of the productive soils of alluvial plains. To begin our study, the general characteristics of the Seco river basin have been considered, including geology, geomorphology, climate, soils, and anthropic activities. In addition, specific features of the sub-basin that contributes its waters to the meander section were also taken into account: the increase of the flows due to the change toward the use of surrounding soils, the slopes of the field, the geomorphological region and morphometry. Landsat and Sentinel satellite images, as well as the SRTM Digital Elevation Model (DEM), were used for mapping the channel and crops. The resulting maps are basin and sub-basin watershed contribution to the meanders, slopes, elevation curves, and drainage network. The results show that the sinuosity of the channel increased in the period 1972-2002, had a notable decrease in the period 2002-2011 due to the processes of meander cuts, and increased again in the period 2011-2017, together with the migration of the channel towards the southern quadrant. These changes resulted in the loss of 370.68 ha of productive soils, which represents 7.41 hm3 of sediments removed and transported by the current. The meanders of the Seco river reflect the degradation of its area of contribution, representing the situation of the basins of the Argentine Northwest, in which the increase in the intensity and frequency of the precipitations since 1970 have generated critical conditions, whose effects are more evident in low areas. [ABSTRACT FROM AUTHOR]

Thin-film magneto-impedance (MI) biosensors have attracted significant attention due to their high sensitivity and easy miniaturization. However, further improvement is required to detect weak biomagnetic signals. Here, we report a meander thin-film biosensor preparation to investigate the fabrication parameters influencing the MI effect. Specifically, we hypothesized that an optimal film thickness and sensing area size ratio could be achieved to obtain a maximum MI ratio. A meander multilayer MI biosensor based on a NiFe/Cu/NiFe thin-film was designed and fabricated into 3-, 6-, and 9-turn models with film thicknesses of 3 µm and 6 µm. The 9-turn biosensor resembled the largest sensing area, while the 3- and 6-turn biosensors were designed with identical sensing areas. The results indicated that the NiFe film thickness of 6 µm with a sensing area size of 14.4 mm2 resembling a 9-turn MI biosensor is the optimal ratio yielding the maximum MI ratio of 238%, which is 70% larger than the 3- and 6-turn structures. The 3- and 6-turn MI biosensors exhibited similar characteristics where the MI ratio peaked at a similar value. Our results suggest that the MI ratio can be increased by increasing the sensing area size and film thickness rather than the number of turns. We showed that an optimal film thickness to sensing area size ratio is required to obtain a high MI ratio. Our findings will be useful for designing highly sensitive MI biosensors capable of detecting low biomagnetic signals.

Stability of streambeds is dependent on different factors some of which maybe destabilized at any moment. Dam erection on the riverbed is the most important among those factors. Some morphological changes of a meandering river, the most obvious of which are the gradient change and the area deducted or added to the riverbed, were studied downstream of the Karkheh Dam. To delineate the areas, which had been taken from or added to the riverbed due to the lateral and longitudinal displacement of the meanders, morphology of the downstream river bed prior to and after the dam construction were studied employing satellite imagery, and their extent was calculated using the CCHE2D model. Slope reduction, as expected, follows an increase in the riverbed breadth. The average width of the riverbed was reduced from 273 m to 60 m (78% reduction) after the dam construction. The land taken off the streambed was almost 21 hectares for each kilometer of the length of the river. Mean, maximum and minimum horizontal thalweg displacements were 340,768 and 53 meters, respectively; 56% of the displacements were towards right (west) and 59% of the displacement took place out of the original streambed. The mean annual lateral displacement of the riverbed was 34 meters after the dam construction. This finding illustrates the instability of the terrain through which the river flows.

Many of today’s stretchable interconnection technologies make extensive use of meandered interconnections, these provide 2-D in-plane springs capable of extending and compressing as the need arises. While a significant quantity of research work exists on these interconnects, few generic methodologies exist to design circuits in a consistent manner. This shortfall leads to questionable design practices, which can negatively affect reliability and performance. Presented within this paper is a method to quickly determine which meander fits within a given area based on common geometric boundary conditions. [ABSTRACT FROM AUTHOR]

Spin valves Ta/(Ni80Fe20)60Cr40/Co70Fe20Ni10/Cu/Co70Fe20Ni10/Ru/Co70Fe20Ni10/Fe50Mn50/Ta have been prepared by magnetron sputtering. It was found that the shift of low-field hysteresis loop with respect to H = 0 oscillates as the copper layer thickness changes. Structural studies showed the high perfection of the layer microstructure. Films of spin valves with the copper layer thickness corresponding to the second antiferromagnetic RKKI interaction maximum have been synthesized. They exhibit zero shift of low-field hysteresis loop and are characterized by high magnetoresistance effect. Sensing elements in the form of meanders prepared using the films demonstrate the almost anhysteretical field dependence of magnetoresistance and a magnetoresistive sensitivity of 0.5%/Oe. [ABSTRACT FROM AUTHOR]

Meandering rivers have a dynamic planform, which means that rivers move in radial direction with variable velocities. The movement velocities can be estimated from historical maps of specific river or using mathematical approach. There is not explicit method or suitable algebraic equation for estimation of river meander movement velocities. In this study, experiments were carried out in a laboratory flume, to develop novel equations to calculate meandering river movement velocities. We designated these empirical equations as the river resistance equations. The experiments were conducted with non-uniform, nonchosive sediment in a re-circulating flume with changeable slopes. The influence of bankfull discharge, bed slope and channel width on the meander movement velocities were discussed. Based on the experimental data, three novel empirical equations for prediction of Wx and Wexp and Wm were proposed. Moreover, the shuffled complex evolution (SCE) optimization algorithm was used to estimate the unknown parameters of the empirical equations. To validate SCE method, the result was compared with traditional multiple regression analysis. This comparison indicated that the SCE optimization algorithm outperformed the multiple regression analysis method in the empirical equations calibration. [ABSTRACT FROM AUTHOR]

The status of ”reality” in visual and literary art is the subject of research of this paper. By doing a comparative reading of both a visual and a literary text, different reality transposition models and semantic aspects in both arts will be pursued, as well as potential strategic characteristics that they have in common. The focus of this paper will be Julije Knifer’s paintings and Davor Špišić’s journal integrated as part of Slavonian war prose.

The Shirley Basin is a small asymmetric synclinal structure located in northern Carbon County, Wyoming approximately 65 km (40 miles) south of Casper, Wyoming, USA. The basin formed during the Laramide orogeny of the Late Cretaceous to Early Tertiary (78-49 Ma) and contains economically significant uranium deposits. The underlying Cretaceous units form an angular unconformity with the overlying Tertiary units that represents a paleotopographic erosional surface characterized by stream channels and overbank deposits of interbedded sand and clay with some organic detritus. Furthermore, the Cretaceous shales function as the lower confining unit/aquitard for in-situ recovery (ISR) uranium mining, and the overlying Tertiary sandstones host the uranium mineralization. This study maps the K/T boundary in greater detail than previous studies and identifies paleotopographic features that influence sedimentary environments and structures that favor uranium mineralization. Using a larger study region and thousands of historical wells and associated electric logs not available to previous studies, this research identifies unit boundaries and enters them into Golden Software's Surfer and Esri's ArcGIS to construct a detailed structure contour map on the K/T surface. The map delineates paleotopography such as hills and river channels, with the latter showing a strong spatial association with uranium mineralization. Geologists can use these maps to identify thicker host sands and fluvial features which enhance uranium mineralization. Mining companies can reduce operational and exploration costs by drilling in these more favorable areas to efficiently delineate the ore body geometry and develop more accurate mine unit designs that will maximize uranium recovery. [ABSTRACT FROM AUTHOR]

One-decade-long observations of post-cut-off channel development and oxbow lake formation are presented to offer insight into the morphological response of the Morava River to neck cut-off. The main objectives were: calculation of the amount of sediment released to the channel by collapse of the meander neck; comparison of floodplain erosion and deposition rates before and after cut-off; and description of the rate and pattern of oxbow lake sedimentation. The amount of sediment released due to cut-off (~35 000 m3) equalled 2-5 years of sediment input by lateral erosion averaged for the past six decades. Bank erosion rates substantially exceeded long-term averages (0.63-6.21 m year−1, post cut-off). Despite a low entrance angle, alluvial plugs in a newly formed oxbow lake were established within a few months. Between 2006 and 2016, sedimentation of the alluvial plugs proceeded at an average rate of 0.55 m year−1, reflecting the time since cut-off and the frequency of overbank flows. [ABSTRACT FROM AUTHOR]

Metallic multilayer spin-valve nanostructures that comprise the exchange-coupled ferromagnet/ Ru/ferromagnet structure in the free layer have been synthesized by magnetron sputtering. For microobjects (meanders) formed from CoFe/Cu/CoFe/Ru/CoFe/FeMn/Ta spin valves with different thicknesses of ruthenium and copper layers, the dependences of the magnetoresistive sensitivity and low-field hysteresis loop shift on the meander strip width have been studied. Sensing elements characterized by high magnetoresistive sensitivity have been manufactured. [ABSTRACT FROM AUTHOR]

Hydrologic changes of the nature will gradually cause changes in conditions and morphology of rivers. Dalki River is one of the rivers that is current in Fars and Booshehr provinces. This river is a permanent one with the length of 225 kilometers and its average slope is 8 percent. Therefore, according to the unique features of this river and frequency of the formed meanderings through the river, it was decided to provide its maps. The maps were provided using remote sensing techniques, GIS, and satellite images in a 38-year period and via physical tools of the research including Topography maps 1/1,250000/50000, geology and pedology maps, slope and height map of the basin, DEM of the region, landsat images, and MSS and OLI sensors in the first stage in Arc GIS software. Then, using the provided maps, all of the effective factors on meandering of the Dalki river were analyzed and finally according to the data analysis, the maximum displacement of the river was clarified and it was perceived that slope and type of the formations were the significant factors of changes and meanders of this river so that decrease and increase in the slope and type of the formations divided the chronologic-historical classification of this river into three young, adult, and old parts. During this 38-year period, the numbers of meanders have been increased as well as the displacement of the river in comparison to the past. [ABSTRACT FROM AUTHOR]

Hydrologic changes of the nature will gradually cause changes in conditions and morphology of rivers. Dalki River is one of the rivers that is current in Fars and Booshehr provinces. This river is a permanent one with the length of 225 kilometers and its average slope is 8 percent. Therefore, according to the unique features of this river and frequency of the formed meanderings through the river, it was decided to provide its maps. The maps were provided using remote sensing techniques, GIS, and satellite images in a 38-year period and via physical tools of the research including Topography maps 1/1,250000/50000, geology and pedology maps, slope and height map of the basin, DEM of the region, landsat images, and MSS and OLI sensors in the first stage in Arc GIS software. Then, using the provided maps, all of the effective factors on meandering of the Dalki river were analyzed and finally according to the data analysis, the maximum displacement of the river was clarified and it was perceived that slope and type of the formations were the significant factors of changes and meanders of this river so that decrease and increase in the slope and type of the formations divided the chronologic-historical classification of this river into three young, adult, and old parts. During this 38-year period, the numbers of meanders have been increased as well as the displacement of the river in comparison to the past. [ABSTRACT FROM AUTHOR]

Meanders, as a interesting water flow patterns in nature, is giving dynamic to courses of rivers.Creation of curvature on courses of rivers is give enough energy for migrate active channel on floodplain. This migration is main reason for many geomorphology in events is floodplains and at final is changing the floodplain pattern .These changing is created many problems for man-made structures that is constructed at bank or on courses of rivers. Aji-Chay River, as a typical meander is migrate on floodplain by creation curvature on its course (is situated at 37° 58′ to 38° 07′ N and from 46° 15′ to 47 °45′ W). In this article is analyzed and estimated migration rate, migration potential and time of migration ,by use of experimental methods, by satellite and areal images In this study rely on parameters of meanders, as bind and width of river corridor is estimated by use of W methods and ∆t, R/W calculation, in order to investigation on capability of rivers for movement .In this study also is estimated time of active channel migration on floodplain by use of valid methods .The results of this study show that active channel of Aji-Chay repeatedly movement on floodplain in during time and because these movement and changing and bank erosion, is flatten the floodplain .In part of Aji-Chay course time period for completed a cycle of migration is from 1 to over 5 years. This period is vary in many parts of river course. The results of this study also suggested that sinuosity rate at length of Aji-Chay course is changed in during time and old race of water flow is evidence these changes.