scholarly journals Using High-Spatial Resolution UAV-Derived Data to Evaluate Vegetation and Geomorphological Changes on a Dune Field Involved in a Restoration Endeavour

2021 ◽  
Vol 13 (10) ◽  
pp. 1987
Author(s):  
Stefano Fabbri ◽  
Edoardo Grottoli ◽  
Clara Armaroli ◽  
Paolo Ciavola
Keyword(s):  
High Resolution ◽  
Low Cost ◽  
Sand Dunes ◽  
Progressive Increase ◽  
Dune System ◽  
Coastal System ◽  
Stable Pattern ◽  
The North ◽  
Bare Sand ◽  
Crest Line

Nowadays, the employment of high-resolution Digital Surface Models (DSMs) and RGB orthophotos has become fundamental in coastal system studies. This work aims to explore the potentiality of low-cost Unmanned Aerial Vehicle (UAV) surveys to monitor the geomorphic and vegetation state of coastal sand dunes by means of high-resolution (2–4 cm) RGB orthophotos and DSMs. The area of study (Punta Marina, Ravenna, Italy), in the North Adriatic Sea, was considered very suitable for these purposes because it involves a residual coastal dune system, damaged by decades of erosion, fragmentation and human intervention. Recently, part of the dune system has been involved in a restoration project aimed at limiting its deterioration. RGB orthophotos have been used to calculate the spectral information of vegetation and bare sand and therefore, to monitor changes in their relative cover area extension over time, through the using of semi-automatic classification algorithms in a GIS environment. Elevation data from high-resolution DSMs were used to identify the principal morphological features: (i) Dune Foot Line (DFL); (ii) Dune Crest Line (DCL); Dune seaward Crest Line (DsCL); Stable Vegetation line (SVL). The USGS tool DSAS was used to monitor dune dynamics, considering every source of error: a stable pattern was observed for the two crest lines (DCL and DsCL), and an advancing one for the others two features (DFL and SVL). Geomorphological data, as well as RGB data, confirmed the effectiveness of planting operations, since a constant and progressive increase of the vegetated cover area and consolidation of the dune system was observed, in a period with no energetic storms. The proposed methodology is rapid, low-cost and easily replicable by coastal managers to quantify the effectiveness of restoration projects.

High-resolution melting analysis of common and recombinant genotypes of the Atlantic cod (Gadus morhua) hemoglobin β1 gene in transatlantic populations

2012 ◽  
Vol 69 (3) ◽  
pp. 525-531 ◽  
Author(s):  
Ola Frang Wetten ◽  
Robert C. Wilson ◽  
Øivind Andersen
Keyword(s):  
High Resolution ◽  
Atlantic Ocean ◽  
Gadus Morhua ◽  
Elevated Temperatures ◽  
High Resolution Melting ◽  
Atlantic Cod ◽  
North Atlantic Ocean ◽  
Low Cost ◽  
Northeast Atlantic ◽  
The North

High-resolution melting (HRM) analysis was applied to haplotype the Met55Val–Lys62Ala mutations of the Atlantic cod ( Gadus morhua ) Hb-β1 gene responsible for the important hemoglobin polymorphisms. The Val55–Ala62 haplotype predominated in cod populations throughout the Northwest Atlantic Ocean and the northern Norwegian and Baltic seas, while the Met55–Lys62 variant was mostly found in the North Sea, Kattegat, and along the southern part of the Norwegian coast. Whereas the distribution of the two main haplotypes show a temperature-related north–south gradient in Northeast Atlantic populations, this study provided no evidence for such a cline on the western side of the North Atlantic Ocean. Coupling and repulsion double heterozygotes were readily distinguished by the HRM assay, but no repulsion heterozygote specimens were found on either side of the Atlantic Ocean. The recombinant haplotype Val55–Lys62 was detected in variable numbers in both Northwest and Northeast Atlantic populations, with the highest frequencies in the Canadian populations. The reciprocal Met55–Ala62 recombination was almost absent in the populations examined and probably represents a disadvantage, particularly at elevated temperatures. Our HRM assay affords low-cost, precise, and efficient Hb-β1 polymorphism haplotyping in large numbers of DNA samples in small, moderately equipped laboratories.

scholarly journals Low-Cost UAV for High-Resolution and Large-Scale Coastal Dune Change Monitoring Using Photogrammetry

2019 ◽  
Vol 7 (3) ◽  
pp. 63 ◽  
Author(s):  
Quentin Laporte-Fauret ◽  
Vincent Marieu ◽  
Bruno Castelle ◽  
Richard Michalet ◽  
Stéphane Bujan ◽  
...  
Keyword(s):  
High Resolution ◽  
Large Scale ◽  
Morphological Evolution ◽  
Spatial Scales ◽  
Low Cost ◽  
Control Point ◽  
Coastal Dune ◽  
Surface Model ◽  
High Temporal Resolution ◽  
Dune System

In this paper, coastal dune data are collected at Truc Vert, SW France, using photogrammetry via Unmanned Aerial Vehicles (UAVs). A low-cost GoPro-equipped DJI Phantom 2 quadcopter and a 20 MPix camera-equipped DJI Phantom 4 Pro quadcopter UAVs were used to remotely sense the coastal dune morphology over large spatial scales (4 km alongshore, i.e., approximately 1 km2 of beach-dune system), within a short time (less than 2 h of flight). The primary objective of this paper is to propose a low-cost and replicable approach which, combined with simple and efficient permanent Ground Control Point (GCP) set-up, can be applied to routinely survey upper beach and coastal dune morphological changes at high frequency (after each storm) and high resolution (0.1 m). Results show that a high-resolution and accurate Digital Surface Model (DSM) can be inferred with both UAVs if enough permanent GCPs are implemented. The more recent DJI Phantom 4 gives substantially more accurate DSM with a root-mean-square vertical error and bias of 0.05 m and −0.03 m, respectively, while the DSM inferred from the DJI Phantom 2 still largely meets the standard for coastal monitoring. The automatic flight plan procedure allows replicable surveys to address large-scale morphological evolution at high temporal resolution (e.g., weeks, months), providing unprecedented insight into the coastal dune evolution driven by marine and aeolian processes. The detailed morphological evolution of a 4-km section of beach-dune system is analyzed over a 6-month winter period, showing highly alongshore variable beach and incipient foredune wave-driven erosion, together with wind-driven inland migration of the established foredune by a few meters, and alongshore-variable sand deposition on the grey dune. In a context of widespread erosion, this photogrammetry approach via low-cost flexible and lightweight UAVs is well adapted for coastal research groups and coastal dune management stakeholders, including in developing countries where data are lacking.

Development of hybrid aeolian dunes: the William River dune field, northwest Saskatchewan, Canada

1986 ◽  
Vol 23 (12) ◽  
pp. 1974-1990 ◽  
Author(s):  
M. A. Carson ◽  
P. A. MacLean
Keyword(s):  
Large Scale ◽  
Sand Dunes ◽  
Progressive Increase ◽  
Sand Transport ◽  
Asymmetric Distribution ◽  
Wind Regime ◽  
The North ◽  
Field Evidence ◽  
Aeolian Dunes ◽  
Sand Movement

Observations have been made on the structure, morphology, and pattern of sand movement on large-scale, roughly elongate, northwest–southeast-aligned aeolian sand dunes in a desert area of northern Saskatchewan, Canada. Transverse profiles show steeper northeast flanks, the lower parts of which are covered with psammophilous grasses. Dune structure is dominated by northeast-dipping accretion laminae, and 14C dates of organic material trapped between such exposed laminae on the southwest flank indicate migration to the northeast at about 0.5 m/year in the last few centuries. On the other hand, there is a progressive increase in height, bulk, symmetry, and peakedness of the dunes from northwest to southeast, suggestive of substantial along-dune sand movement. The present-day wind regime shows a potential resultant sand-transport vector to the southeast, virtually parallel to the dune axis; winds from the north-northeast and northeast dominate the first 6 months of the year, followed by winds from the west-southwest in the latter half. Field evidence of airflow and sand-movement patterns upon the surfaces of two dunes also indicates a strong along-dune component. The dunes are interpreted as hybrid landforms reflecting both transverse and longitudinal processes acting at the present time. Of particular sedimentological significance is the discordance between dune stratigraphy and the wind regime. Dune structure is controlled by a southwest–northeast imbalance in sand movement assumed to result from an asymmetric distribution of sand-trapping vegetation and from a seasonal contrast in sand mobility that partly correlates with seasonality in the wind regime. Both factors promote northeast migration normal to the potential resultant of effective winds.

scholarly journals A high-resolution solar spectrum 2000 Å–2200 Å

1970 ◽  
Vol 36 ◽  
pp. 271-273
Author(s):  
B. B. Jones ◽  
B. C. Boland ◽  
R. Wilson ◽  
S. T. F. Engstrom
Keyword(s):  
High Resolution ◽  
Solar Spectrum ◽  
Solar Image ◽  
Roll Control ◽  
North East ◽  
The North ◽  
Alignment System ◽  
Optical Alignment ◽  
South Axis ◽  
System Operating

A high-resolution solar spectrum in the range 2000–2200 Å was obtained in a recent flight of a sunpointing Skylark rocket. This was launched at 04.21 hr UT on April 22, 1969 from Woomera and reached an apogee of 178 km. An optical alignment system operating on the main vehicle pointing system gave a net stabilisation of ±3 arc sec in the position of the solar image relative to the spectrograph slit. The slit, of length 1.0 mm, was set in the north-east quadrant parallel to and 5 arc min from the north/south axis, its lower edge being 1 arc min from the equator. The roll control of ±2.5° was provided entirely by the standard Elliott Bros. type of vehicle stabilisation.

scholarly journals Fabrication and Compressive Behavior of a Micro-Lattice Composite by High Resolution DLP Stereolithography

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 785
Author(s):  
Chow Shing Shin ◽  
Yu Chia Chang
Keyword(s):  
High Resolution ◽  
Lattice Structure ◽  
Low Cost ◽  
Hierarchical Structures ◽  
Dip Coating ◽  
Unit Cell ◽  
Digital Light Processing ◽  
Unit Cell Size ◽  
Wide Range ◽  
And Performance

Lattice structures are superior to stochastic foams in mechanical properties and are finding increasing applications. Their properties can be tailored in a wide range through adjusting the design and dimensions of the unit cell, changing the constituent materials as well as forming into hierarchical structures. In order to achieve more levels of hierarchy, the dimensions of the fundamental lattice have to be small enough. Although lattice size of several microns can be fabricated using the two-photon polymerization technique, sophisticated and costly equipment is required. To balance cost and performance, a low-cost high resolution micro-stereolithographic system has been developed in this work based on a commercial digital light processing (DLP) projector. Unit cell lengths as small as 100 μm have been successfully fabricated. Decreasing the unit cell size from 150 to 100 μm increased the compressive stiffness by 26%. Different pretreatments to facilitate the electroless plating of nickel on the lattice structure have been attempted. A pretreatment of dip coating in a graphene suspension is the most successful and increased the strength and stiffness by 5.3 and 3.6 times, respectively. Even a very light and incomplete nickel plating in the interior has increase the structural stiffness and strength by more than twofold.

scholarly journals Optimal design of the solar tracking system of parabolic trough concentrating collectors

2020 ◽  
Vol 15 (4) ◽  
pp. 613-619
Author(s):  
Li Kong ◽  
Yunpeng Zhang ◽  
Zhijian Lin ◽  
Zhongzhu Qiu ◽  
Chunying Li ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Solar Radiation ◽  
Tracking System ◽  
Low Cost ◽  
Parabolic Trough ◽  
The North ◽  
Tracking Mode ◽  
Solar Tracking ◽  
East West

Abstract The present work aimed to select the optimum solar tracking mode for parabolic trough concentrating collectors using numerical simulation. The current work involved: (1) the calculation of daily solar radiation on the Earth’s surface, (2) the comparison of annual direct solar radiation received under different tracking modes and (3) the determination of optimum tilt angle for the north-south tilt tracking mode. It was found that the order of solar radiation received in Shanghai under the available tracking modes was: dual-axis tracking > north-south Earth’s axis tracking > north-south tilt tracking (β = 15°) > north-south tilt tracking (β = 45) > north-south horizontal tracking > east-west horizontal tracking. Single-axis solar tracking modes feature simple structures and low cost. This study also found that the solar radiation received under the north-south tilt tracking mode was higher than that of the north-south Earth’s axis tracking mode in 7 out of 12 months. Therefore, the north-south tilt tracking mode was studied separately to determine the corresponding optimum tilt angles in Haikou, Lhasa, Shanghai, Beijing and Hohhot, respectively, which were shown as follows: 18.81°, 27.29°, 28.67°, 36.21° and 37.97°.

X-ray computed microtomography for the structural analysis of jewelry from the Museum “Royal Tombs of Sipán”

2020 ◽  
Vol 35 (S1) ◽  
pp. S38-S42
Author(s):  
Soraia Rodrigues de Azeredo ◽  
Roberto Cesareo ◽  
Angel Guillermo Bustamante Dominguez ◽  
Ricardo Tadeu Lopes
Keyword(s):  
Structural Analysis ◽  
High Resolution ◽  
Copper Alloys ◽  
North Coast ◽  
Flat Panel ◽  
X Ray ◽  
The North ◽  
Gold Silver ◽  
Computed Microtomography ◽  
X Ray Computed

Precious ornaments from the Museum Royal Tombs of Sipán were analyzed by X-ray computed microtomography (microCT). The ornaments analyzed were golden earrings produced by the Moche culture that flourished along the north coast of present-day Peru between approximately 100 and 600 AD. Sipán, also known as Huava Rajada, is a mochica archaeological complex in the north of Peru. In particular, the spectacular jewelry, mainly composed of gold, silver, and copper alloys, gilded copper, and tumbaga, from the Museum “Royal Tombs of Sipán,” in Lambayeque, north of Peru, are some of the most sophisticated metalworking ever produced of pre-Columbian America. A portable microCT system consisting of a high-resolution flat panel detector and a mini X-ray tube were used for the structural analysis of these ornaments. The microCT images show parts of the internal structure, highlighting the manufacturing technique and gold sheets joining techniques of the Moche artisans. Furthermore, the advantage of using the portable microCT system for nondestructive testing is clear when the sample cannot be taken to the laboratory.

Sign in / Sign up

Export Citation Format

Share Document