scholarly journals Building stone quarries: resource evaluation by block modelling and unmanned aerial photogrammetric surveys

2021 ◽  
Vol 81 (1) ◽  
Author(s):  
Maxim Bogdanowitsch ◽  
Luís Sousa ◽  
Siegfried Siegesmund

AbstractThe production of building stones shown an exponential growth in last decades as consequences of the demand and developments in the extraction and processing techniques. From the several conditioning factors affecting this industry, the geological constrains at quarry scale stands out as one of most important. Globalization and increasing competition in the building stone market require large raw material blocks to keep further processing as cost-effective as possible. Therefore, the potential extraction volume of in-situ stone blocks plays an important role in the yield of a dimensional stone quarry. The full characterization of the fracturing in the quarries comes up as fundamental in the assessment of the in-situ blocks volume/shape and potential extracted raw blocks. Identify the joint sets present, their spacing and the differences across the quarry demands a continuous assess during the quarry live span. Information from unmanned aerial vehicles helps in the field survey, namely trough digital surface models, orthophotos, and three-dimensional models. Also, the fracturing modelling by specific software programs is crucial to improve the block size assessment and the increase the quarry yield. In this research fracturing of twenty-one quarries of granite, limestone, marble, and slate from Portugal were assessed by combining field surveys with new techniques. From the studied quarries several cases were selected and presented to highlight the importance of this combined methodology in the fracturing assessment and how they can be helpful in the maximization of the resources and quarry management.

2007 ◽  
Vol 342-343 ◽  
pp. 133-136
Author(s):  
Jae Bong Choi

The objective of this study was to quantify the zonal difference of the in situ chondron’s Poisson effect under different magnitudes of compression. Fluorescence immunolabeling for type VI collagen was used to identify the pericellular matrix (PCM) and chondron, and a series of fluorescent confocal images were recorded and reconstructed to form quantitative three-dimensional models. The zonal variations in the mechanical response of the chondron do not appear to be due to zonal differences in PCM properties, but rather seem to result from significant inhomogeneities in relative stiffnesses of the extracellular matrix (ECM) and PCM with depth.


OENO One ◽  
2019 ◽  
Vol 53 (4) ◽  
Author(s):  
Khalil Bou Nader ◽  
Leonard Maximilian Pfahl ◽  
Eric Gomès ◽  
Manfred Stoll

Background and aims: Measurement of grapevine size is necessary to assess carbon reserves at the level of individual vines and to estimate the carbon sequestration potential of vineyards. Methods of measurement rely mostly on traditional dendrological techniques that may be prone to error. In this study, we examined the use of structure-from-motion with multiview stereophotogrammetry (SfM-MVS) to obtain accurate measurements of vine trunk thickness and volume. SfM-MVS enables the creation of scaled, georeferenced three-dimensional models based on a set of overlapping photographs.Methods and results: The study was conducted using field-grown Vitis vinifera L. cv. Riesling vines aged 5, 22 and 46 years and pruned in a bilateral Guyot. Trunk diameter, cross-sectional area and circumference 10 cm above the grafting point were measured by traditional dendrometry, and the values obtained compared with corresponding estimates from reconstructed three-dimensional SfM-MVS models. SfM-MVS was also used to estimate total trunk volume. Correlation between measured values and modelled estimates was close to unity (0.976 ≤ R2 ≤ 0.988). The estimates for 5-year-old vines had the largest errors.Conclusions: Under adequate lighting conditions and with sufficient image resolution, SfM-MVS is able to produce accurate models of vine trunks.Significance of the study: This work serves as proof of concept for the use of SfM-MVS to measure the trunk size of field-grown grapevines of different ages. This technique, which is relatively new, is cost-effective and easy to implement. Further research is necessary to determine specific applications of SfM-MVS, in which it could supplement or replace traditional dendrological techniques.


Drones ◽  
2019 ◽  
Vol 3 (3) ◽  
pp. 63 ◽  
Author(s):  
Narcisa G. Pricope ◽  
Kerry L. Mapes ◽  
Kyle D. Woodward ◽  
Steele F. Olsen ◽  
J. Britton Baxley

There is a growing demand for the collection of ultra-high spatial resolution imagery using unmanned aerial systems (UASs). UASs are a cost-effective solution for data collection on small scales and can fly at much lower altitudes, thus yielding spatial resolutions not previously achievable with manned aircraft or satellites. The use of commercially available software for image processing has also become commonplace due to the relative ease at which imagery can be processed and the minimal knowledge of traditional photogrammetric processes required by users. Commercially available software such as AgiSoft Photoscan and Pix4Dmapper Pro are capable of generating the high-quality data that are in demand for environmental remote sensing applications. We quantitatively assess the implications of processing parameter decision-making on UAS product accuracy and quality for orthomosaic and digital surface models for RGB and multispectral imagery. We iterated 40 processing workflows by incrementally varying two key processing parameters in Pix4Dmapper Pro, and conclude that maximizing for the highest intermediate parameters may not always translate into effective final products. We also show that multispectral imagery can effectively be leveraged to derive three-dimensional models of higher quality despite the lower resolution of sensors when compared to RGB imagery, reducing time in the field and the need for multiple flights over the same area when collecting multispectral data is a priority. We conclude that when users plan to use the highest processing parameter values, to ensure quality end-products it is important to increase initial flight coverage in advance.


2020 ◽  
Vol 17 (2) ◽  
pp. 131-135
Author(s):  
Zohreh Shahnavaz ◽  
Lia Zaharani ◽  
Mohd Rafie Johan ◽  
Nader Ghaffari Khaligh

Background: In continuation of our previous work and the applications of saccharin, we encouraged to investigate the one-pot synthesis of the aryl iodides by the diazotization of the arene diazonium saccharin salts. Objective: Arene diazonium salts play an important role in organic synthesis as intermediate and a wide variety of aromatic compounds have been prepared using them. A serious drawback of arene diazonium salts is their instability in a dry state; therefore, they must be stored and handled carefully to avoid spontaneous explosion and other hazard events. Methods: The arene diazonium saccharin salts were prepared as active intermediates in situ through the reaction of various aryl amines with tert-butyl nitrite (TBN) in the presence of saccharin (Sac–H). Then, in situ obtained intermediates were used into the diazotization step without separation and purification in the current protocol. Results: A variety of aryl iodides were synthesized at a greener and low-cost method in the presence of TBN, Sac–H, glacial acetic acid, and TEAI. Conclusion: In summary, a telescopic reaction is developed for the synthesis of aryl iodides. The current methodology is safe, cost-effective, broad substrate scope, and metal-free. All used reagents are commercially available and inert to moisture and air. Also, the saccharine and tetraethylammonium cation could be partially recovered from the reaction residue, which reduces waste generation, energy consumption, raw material, and waste disposal costs.


2015 ◽  
Vol 3 (5) ◽  
pp. 1953-1960 ◽  
Author(s):  
Lingjie Li ◽  
Jing Xu ◽  
Jinglei Lei ◽  
Jie Zhang ◽  
Frank McLarnon ◽  
...  

The Ni(OH)2 hexagonal platelets were in situ fabricated on Ni foam as a binder-free supercapacitor electrode material with high performance and excellent cycling stability by a one-step, cost-effective, green hydrothermal treatment of three-dimensional (3D) Ni foam in a 15 wt% H2O2 aqueous solution.


2008 ◽  
Vol 17 (5) ◽  
pp. 825-832 ◽  
Author(s):  
Chris D. Bryce ◽  
Jason L. Pennypacker ◽  
Nikhil Kulkarni ◽  
Emmanuel M. Paul ◽  
Christopher S. Hollenbeak ◽  
...  

Geophysics ◽  
1998 ◽  
Vol 63 (6) ◽  
pp. 1965-1970 ◽  
Author(s):  
Gregory N. Tsokas ◽  
Alexandros Stampolidis ◽  
Antonis D. Angelopoulos ◽  
Stefanos Kilias

Mining activities in Lavrion began during the first millennium B.C. after the decline of ancient Athens and then restarted more deliberately during the nineteenth century. Aeromagnetic data from a 1967 survey of the mining area was recompiled, processed, and interpreted for the present study. The original flight lines were digitized and leveled, and the international geomagnetic reference field (IGRF) was removed. The data were inverted by means of a terracing technique that defines separate domains of uniform distribution of physical properties that cause the magnetic anomalies. The log power spectrum was computed; along with the results of terracing, it suggested the existence of two sources of the magnetic anomaly. The long‐wavelength anomaly reflects a large, concealed body that is most probably a granitic intrusion, consistent with local geological evidence. The source of the short‐wavelength anomaly is a strongly magnetized body attributed to the net effect of various thin, magnetite‐bearing sulfide zones. The anomalies were then separated in the wavenumber domain. Magnetic susceptibility measurements were made in situ on the exposed parts of the local formations. Three‐dimensional models whose effect simulates the observed anomalies were calculated. Results of the modeling show that the large magnetic body is buried at 0.68 km depth. The small, relatively shallow body is about 0.035 km thick and buried at 0.6 km depth. The bodies do not show any corresponding gravity anomaly on the regional Bouguer gravity anomaly map.


Author(s):  
Eva Buranská ◽  
Ivan Buranský ◽  
Ladislav Morovič ◽  
Katarína Líška

Abstract The paper is focused on additive manufacturing (AM) which is the process of producing objects from a three-dimensional (3D) model by joining materials layer by layer, as opposed to the subtractive manufacturing methodologies [1], directly from raw material in powder, liquid, sheet, or a filament form without the need for moulds, tools, or dies. The article demonstrates potential environmental implications of additive manufacturing related to the key issues including energy use, occupational health, waste and lifecycle impact. AM provides a cost-effective and time-efficient way to fabricating products with complicated geometries, advanced material properties and functionality. Based on this review, we identified that additive manufacturing will have a significant societal impact in the near future. A critical technical review of the promises and potential issues of AM is beneficial for advancing its further development.


2021 ◽  
Vol 32 (3) ◽  
pp. 290-298
Author(s):  
Neo Tshabalala ◽  
Kasongo Nyembwe ◽  
Malan Van Tonder

Applications of three-dimensional printing (3DP) to sand casting have been well-established in the last two decades. The preferred raw material is silica (quartz) sand, as it is the most readily available and cost effective sand. However, silica sand as a refractory material has some technical limitations, including high thermal linear expansion, low refractoriness, and thermal conductivity. Therefore, it is not suitable for all castings. Other refractory sand types are available, including chromite sand, which is abundantly available in South Africa. Analysis of the physical and chemical properties of in-laboratory coating of a locally available chromite sand was conducted through known metal foundry tests that provide an understanding of the quality and suitability of the use of chromite sand as a potential substitute for silica material for rapid sand-casting applications. The results of this study will inform the industry about the optimisation of parameters for the manufacturing of a resin-coated chromite sand and its use in additive manufacturing using a Voxeljet VX 1000 printer.


2016 ◽  
Vol 64 (4) ◽  
pp. 442-446
Author(s):  
Ana Waleska Pessoa BARROS ◽  
Érika PORTO ◽  
Jefferson Felipe Silva de LIMA ◽  
Nadja Maria da Silva Oliveira BRITO ◽  
Renata de Souza Coelho SOARES

ABSTRACT The use of rapid prototyping in medical and dental fields consists of three-dimensional models using Computer Aided Design systems and Computer Aided Manufacturing systems. Such systems focus specifically on enhanced 3D visualization tools that provide a precise preoperative planning opportunity through three-dimensional printing, to the professional. The objective of this study was to describe the main steps in the biomodel manufacturing using an Objet 3D printer (CONNEX 350), whose raw material is a light-curing resin. The steps are adopted by researchers from three-dimensional technologies laboratory (LT3D), of the Center for Strategic Technologies in Health (NUTES), from the State University of Paraíba (UEPB), Brazil. It begins with the acquisition of tomographic images that are processed through specific software and exported to the digital Stereo lithography (STL) format. The additive manufacturing technique is Stereo lithography, which consists in the construction of biomodel by photopolymerization of a liquid epoxy resin using ultraviolet radiation. The biomodel that comes from this process was brought to a pressurizing machine to remove the resin support, washing it with water jets. After this step, this biomodel was sent to the health professional in charge. The use of biomodels constitutes a major breakthrough in the area of Dentistry, allowing more precise diagnosis by professionals, simulation and surgical planning, previous adaptation of biomaterials and orthoses, as well as interaction between the surgeon and the patient, thus obtaining more satisfactory aesthetic results and decreased surgical time.


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