The results of a geophysical survey of the technical condition of the lighthouse are presented. The stress–strain state, the residual resource, the tension of the fastening cables, the fixation of ...piles in the ground (rigid/non-rigid), and the immersion depth of the historical study object, the Sukhumi Lighthouse built in 1861 were determined. The passive seismic standing method based on the extraction of the natural vibrations of the object from noise records, as well as the tapping method, based on the recording of a reflected seismic wave passing along the structure were used to solve the above problems.
•A highly eroded Viking Age ring fortress was studied by non-destructive methods.•A multi-method 3D approach clarifies landscape modifications.•The modifications of the landscape are comparable to ...contemporary ring fortresses.•Location and geometry of the monument was fixed according to a pre-conceived plan.
Non-invasive methods are increasingly important for understanding archaeological sites and their contexts. Larger earth-built constructions are nevertheless still difficult to study without extensive excavations. At the recently discovered Viking-Age ring fortress Borgring in Denmark a suite of non-destructive methods was applied with the aim of understanding how this highly eroded earthen fortress was constructed, and investigating how the construction of such a large monument altered the landscape. The methods were 1) residual relief modelling of airborne laser scanning data, 2) electromagnetic induction (DualEM 421 s) survey combined with coring, and 3) soil magnetic susceptibility measurements all to produce a 3D model of the palaeo-landscape and the fortress.
We found that the narrow natural promontory was enlarged to make space for the construction of the fortress’ rampart. The magnetic susceptibility of turfs from the rampart showed that both wetland and upland areas were alternately used for different compartments and explained the segmented anomalies comprising its construction. The combined results revealed a better archaeological understanding of the construction of the rampart, that the modifications of the landscape was somewhat comparative to the contemporary Fyrkat ring fortress site, and that the understanding of the landscape modifications were improved significantly by a multi-method 3D approach.
This article describes the use of non- or minimally destructive methods to study damp in San Juan Bautista Church at Talamanca de Jarama in the Spanish province of Madrid. The combination of ...Electrical Conductivity Meter (EC), Infrared Thermography (IR), RH/T monitoring by means of Data Loggers (DL) and Wireless Sensor Networks (WSN), Electrical Resistivity Tomography (ERT) and Ground-Penetrating Radar (GPR) techniques provided sub-surface and surface information. The respective findings and ranges of observation were inter-related to identify the decay associated with the damp and determine the advantages and drawbacks of each instrumental method. Electrical conductivity meters and infrared thermography deliver rough estimates of the extent of damp on wall surfaces, furnishing qualitative information on the areas where depth studies should be undertaken using techniques such as ERT or GPR or where long-term WSN monitoring sensors should be positioned to determine variability in a given number of points. When the purpose is to distinguish between areas with widely varying moisture contents, ERT is more precise. However, GPR proved to be the most accessible and efficient technique for studying the under-floor profiles.
•A complete study by NDT for moisture control in the cultural heritage is developed.•Evaluation methodology with GPR, ERT, WSN, IRT and contact hygrometry•Observation ranges were inter-related to identify decay in construction materials.•Advantages and drawbacks of each instrumental method are described.•Innovative applications of geophysical techniques for moisture control
This paper presents an experimental investigation of rubber material quality during extrusion phase utilizing vibrational testing. An attempt to classify rubber profile samples including two kinds of ...defects (material based and geometrical), based on the response acquired from vibration test is presented. An experimental apparatus has been built for the purposes of this work. Vibrational signals were captured through a series of experiments and signal processing methods have been used for analysing the captured signals. The investigation revealed that the samples could be classified according to their quality characteristics.
The use of underwater video techniques has expanded rapidly in ecological studies and is particularly desirable in protected areas since the method does not impact the habitat or remove fish. The ...Mediterranean Sea is a biodiversity hotspot under high anthropogenic pressure and consequently, non-destructive and non-extractive techniques for fish monitoring are advantageous. Here, we review 110 publications that used underwater video in fish-related studies in the Mediterranean basin. The most common technique used in the Mediterranean Sea was Remotely Operated Vehicles (ROV) (33%), followed by Remote Underwater Video (RUV) systems (20%), Diver Operated Video (DOV) systems (20%) and Baited Remote Underwater Video (BRUV) systems (19%). Approximately one third of the studies used an additional sampling method, such as fisheries-based or molecular methods with the aim to compare the surveying effectiveness or produce complementary data. The most frequent objectives of the reviewed studies were related to fish community structure, i.e., focusing on community wide metrics such as abundance and biodiversity, or behavioral analyses, while the most commonly studied environments were those of the western Mediterranean and shallow waters, usually involving sandy or rocky reef habitats. Sampling protocols differed widely among studies with transect lengths, soak times and baits all varying. Future research should focus on the least studied parts of the region, such as the eastern and southern Mediterranean Sea and deep-sea habitats. Finally, the development of standardized sampling protocols is recommended to ensure that data are comparable among studies.
The potential of combining artificial neural networks (ANNs) and image processing for assessing leaf relative water content (RWC) and water content (WC) was addressed.
Spathiphyllum wallisii
was ...employed as model species, because it has broad leaves and very responsive stomata. In the course of desiccation, leaves were periodically weighted (to calculate RWC and WC conventionally) and imaged. Image acquisition was performed by a scanner, and was, thus, independent of ambient light environment. Color feature extraction was performed in three color spaces (RGB, HSI, and CIELAB), while six texture statistical features were calculated for each of the (nine) computed color channels. Prior to model development via ANNs, the obtained feature vector underwent feature reduction using principal component analysis. The presented methodology yielded very precise estimations of leaf RWC and WC (correlation coefficient > 0.95). Therefore, the technique under study was proven to be very promising for non-invasive in situ measurements of leaf water status.
Reinforced concrete bridges with post‐tensioned cables are particularly critical structures, as the degradation of the tendons is not fully detectable through conventional investigation methods ...and/or through visual inspections, due to the intrinsic nature of the structural typology. After shortly reviewing the main applications of current non‐destructive (ND) methods available for investigating the deterioration of tendons and grout, the paper presents a simple procedure to rank these methods through a series of metrics formulated to evaluate the various technologies under four different aspects: accuracy of measurement, ease of use, cost, impact on the operation of the bridge. The procedure has the aim of providing bridge owners with a decision tool which can assist in the selection of the optimal ND technology available to detect a particular strand or grout defect.
We report here on the 2019 discovery of an Upper Palaeolithic female figurine at the open-air site of Piatra Neamț in the Bistrița valley, Romania. This figurine, the first ever to be discovered in ...Romania, was found in an area in which Palaeolithic figurative art is extremely poorly represented and such figurines are absent. We shall present the first observations regarding the context of find and materials on the site, the results of the dating of occupations excavated so far and a detailed description of the figurine, for which low- and high-resolution microscopy was used. Its analysis involved several stages of research and the use of non-destructive methods: Particle Induced X-ray Emission (PIXE), FT–Raman vibrational spectroscopy, Computed tomography (CT) scan. In this way, ever since its first publication, the Palaeolithic figurine found at Piatra Neamț has been the subject of several interdisciplinary studies, which have allowed for better description and characterisation of the traces preserved on it.
L’objet de cet article porte sur la découverte en 2019 d’une figurine féminine provenant du site du Paléolithique Supérieur de plein air de Piatra Neamţ (vallée de la Bistriţa). Il s’agit là de la première découverte de ce type sur le territoire de la Roumanie. Elle a été trouvée dans une région où l’art figuratif paléolithique est faiblement représenté. Dans cet article, vont être exposées les premières observations sur le contexte de la découverte et sur les matériaux du site, sur les résultats des datations des habitats fouillés jusqu’à présent, ainsi qu’une description détaillée de la figurine, pour laquelle on a utilisé la microscopie de petite et de grande résolution. Son analyse a nécessité plusieurs étapes de recherches et l’utilisation de méthodes non-destructives : Particle Induced X-ray Emission (PIXE), FT–Raman vibrational spectroscopy, Computed tomography (CT) scan. De cette façon, la statuette féminine de Piatra Neamţ a bénéficié dès le début de plusieurs recherches interdisciplinaires, qui ont permis une meilleure description des traces dont elle était porteuse.
Residual stresses play a pivotal role in determining the durability and service life of the component. Processes such as heating, machining, mechanical treatment and even the manufacturing process ...itself, develop the residual stresses in a component. These initial residual stresses rejig themselves depending on different loading conditions such as rotation, mechanical or thermal loadings. Furthermore, having categorical knowledge about the residual stress field across the whole component is imperative in comprehending how residual stresses impact failure. So, it is vital to determine the stress distribution throughout the component to mitigate the catastrophic failure. This is easy to obtain in case of smaller components due to their small cross-sections, but the same becomes daunting when it comes to large components because of greater depths at which these stresses reside and also of their large cross-sections. Though there are several techniques to measure the residual stresses in large components but work only up to certain depths which restricts there use to specific part dimensions which in turn necessitate to decide the best method for determining the complete stress distribution in large components. Thus, this review aims to elucidate and classify various residual stress measurement methods on the basis of their operating range, principle and technical feasibility with manufacturing process used to manufacture the large engineering components.
Field measurements of soil cracks Stewart, Ryan D.; Najm, Majdi R. Abou
Soil Science Society of America journal,
September/October 2020, Letnik:
84, Številka:
5
Journal Article
Recenzirano
Shrink–swell soils, often classified as Vertisols or vertic intergrades, are found world‐wide and are a leading cause of damage to infrastructure such as buildings, roads, and pipelines. Crack ...networks act as dominant environmental controls on the movement of water, contaminants, and gases. Numerous methods have been proposed to quantify the size (e.g., width, depth, volume) and connectivity of individual cracks and of larger crack networks. To measure and quantify the size and variability of cracks, we focus on two nondestructive methods, called here the tape and rod and displacement approaches, and one destructive method, called here the cast and excavate protocol. The nondestructive methods are relatively inexpensive and can allow repeated measurements, which makes them conducive to use in larger environmental studies such as observing hydrological partitioning between infiltration and surface runoff. However, the nondestructive methods are often biased toward larger cracks (due to physical limitations on the crack sizes that can be measured), require assumptions of crack geometry to determine crack volumes, and typically do not provide information on subsurface connections between cracks. The destructive cast and excavate method is better suited to sample aoftentimes can only be used once (precluding repeated measurements) and is labor intensive. A combination of measurements may therefore be required to best understand crack dynamics in both time and space. Altogether, the methods surveyed here enable accurate measurement and quantification of soil crack characteristics.
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