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1
Xing, Zhihui, Na Wang, Li Shang, Weiwei Jia, and Bingxin Xia. "Structural design for a hybrid stone carving manipulator." Journal of Physics: Conference Series 2133, no. 1 (November 1, 2021): 012035. http://dx.doi.org/10.1088/1742-6596/2133/1/012035.
Анотація:
Abstract With people’s higher and higher requirements for environmental art, a large number of stone carving products are needed in the current urban construction. However, the traditional carving technology and equipment can not meet this demand. The development of robots to complete the processing of stone products, especially for the processing of special-shaped stones with complex shapes such as three-dimensional, multi-faceted and curved surfaces, has great social and economic benefits. In this paper, a stone carving manipulator is designed. In the processing of special-shaped curved stone, the structure of 3-TPS/TP hybrid manipulator is adopted, and its kinematic model and Jacobian matrix are established to realize the efficient automatic processing of special-shaped stone.
2
Kriswandhono, Albertus, and Dwi Yani Yuniawati Umar. "Etno-Arsitektur Umpak-Umpak Batu Tinggalan Budaya Megalitik Masa Protohistori di Lembah Behoa, Kabupaten Poso, Provinsi Sulawesi Tengah." KALPATARU 31, no. 2 (June 30, 2022): 122–33. http://dx.doi.org/10.55981/kpt.2022.2335.
Анотація:
Several structural stones were discovered during research in 1995 – 2004 in Behoa Valley that, if a line is drawn, would form a rectangular polygon with two types of stone, large and small. In 2013, researchers conducted an ethno-architectural study at three megalithic cultural heritage sites in Hanggira Village. The aim is to find out the function of these structured stones. From the results of the ethno-architecture analysis, these structured stones are umpak foundations from dwellings or residential places (Tambi) or places to store special goods or agricultural products (Buho). There is no absolute chronology in the context of the structured stones in the form of umpak foundations. However, from the age of the site, it is expected that these stone umpak foundations had been used since the beginning of the AD century (early metal period) to the protohistoric period.
3
Renker, H. J. "Stone-based structural materials." Precision Engineering 7, no. 3 (July 1985): 161–64. http://dx.doi.org/10.1016/0141-6359(85)90041-8.
4
Yang, Lu, Shi Min Li, Dai Heng Chen, and Zhi Min Wu. "Rolling Stones under the Action of the Numerical Simulation Research Shed Hole." Advanced Materials Research 250-253 (May 2011): 238–41. http://dx.doi.org/10.4028/www.scientific.net/amr.250-253.238.
Анотація:
With a rolling stone gathers tent hole structure as the prototype, using ABAQUS finite element software to simulate the rolling stones impact process with different impact, research rolling angle and speed impact tent hole structural dynamic mechanical response for rolling stone protection design, provide necessary basis. The results show that the rolling stones in different speed and incident angle of tents hole shocks on concrete protective structure of contact force ,displacement and injuries have great influence and for the rolling stones protection engineering design to provide theoretical reference.
5
Monteiro, Gabriel Pereira, Afonso Rangel Garcez de Azevedo, and Markssuel Teixeira Marvila. "Effect of the addition of the natural and treated açaí stone in structural mortars." AIMS Materials Science 8, no. 4 (2021): 608–21. http://dx.doi.org/10.3934/matersci.2021037.
Анотація:
<abstract> <p>The açaizeiro is a palm tree present on a large scale in the northern region of Brazil and in others countries, such as Colombia and Peru, its fruit constitutes one of the main forest products of great economic potential to exportation. However, a generation of large amounts of waste during its processing represents a serious environmental problem, since about 365 tons of açaí stone are discarded in landfills daily in Brazil. The objective of this work was to evaluate the potential of using açaí stone as a substitute of 25% in mass natural sand with filler function, in the development of structural mortars with reference mixture of ratio 1:2:0.45 (cement:sand:water) and waste mixture with1:1.5:0.5:0.45 (cement:sand:açai stone:water), that both mixtures are relationship adopted for structural mortar in the literature. Three different types of mortar were made for evaluation, the reference (without adding stones) and with the addition of natural stone (without treatment and treated with NaOH). After the incorporation of the stones, consistency, water retention, incorporated air content and density in fresh mortars were analyzed, in the fresh state. For evaluation in a hardened state, cylindrical specimens (50 mm × 100 mm) were molded, for compression strength and density tests. The optimum composition was also analyzed with confocal microscopy. It can be seen that in the compression strength tests, mortars with the addition of natural and treated stone showed a reduction, decreasing from 6.25 MPa (reference), to 5.55 MPa (natural stone) and 1.89 MPa (treated stone), this showed that the natural stone mortar was above the minimum of 5.00 MPa reported in the literature. As for density, the evaluations demonstrate a beneficial effect to the incorporation of the stone, which formed lighter mortars, decreasing from 2.12 to 1.79 g/cm<sup>3</sup> in the natural composition and 1.85 g/cm<sup>3</sup> in the treated composition, in both situations with additions, the values were within the maximum limit of 2 g/cm<sup>3</sup> that the literature suggests for structural mortars. In addition, the results of water retention showed an increase in the treated composition (97.28%) in relation to the reference (95.84%), an increase characterized by the treatment in NaOH that reduced the hygroscopic characteristics of the stones, the mixture mortar with treated seed, as well as the reference, presented values above 95%, which is recommended by other studies. The evaluations show that there is a potential for specific structural applications of these mortars, since in all tests the composition with natural stone is within the ideal parameters by Brazilian standard, in addition to helping to solve the environmental impacts caused by discard this waste. As it is a mortar with low compressive strength, its application is suggested for the purpose of repairing specific structural defects that arise in the molding stage of beams, slabs and columns, located in regions with low load demand.</p> </abstract>
6
Mustafaraj, Enea, Erion Luga, Marco Corradi, Antonio Borri, Ylber Muceku, and Aleksandra Zharkalli. "Physical-Mechanical Properties of Stone Masonry of Gjirokastër, Albania." Materials 14, no. 5 (February 27, 2021): 1127. http://dx.doi.org/10.3390/ma14051127.
Анотація:
In addition to reinforced concrete and steel buildings, a large part of the existing building stock in Europe is made of stone masonry. Prediction of the structural behavior requires the development of a systematic material characterization of the mechanical properties and structural details (units, arrangement, bonding, inter-connection). This study aims to analyze the mechanical and physical behavior of building stones in the historical city of Gjirokastër, Albania, known also as the Stone City. A thorough investigation of the regional stone quarries was performed, and the collected samples were cut into regular prismatic specimens for further analysis. The experimental campaign consisted of the determination of flexural strength and compressive strength, water absorption, porosity, specific gravity as well as structural analysis of the masonry material, using the MQI (Masonry Quality Index) method. The test results showed that there is a large scattering in the values of the mechanical and physical stone properties such as compressive strength varying from 20 to 115 MPa and flexural strength from 8 to 25 MPa. However, the analysis of the masonry material revealed a satisfactory structural performance, based on a frequent, systematic respect of the good construction practices (i.e., the rules of the art) in Gjirokastër.
7
Hamad, Feirusha Salih. "Ancient Mesopotamian Stone Bridge: Numerical Modeling and Structural Assessment." Shock and Vibration 2022 (May 10, 2022): 1–11. http://dx.doi.org/10.1155/2022/4255354.
Анотація:
This study aimed to investigate the stress-strain and strain energy density (SED) states of Dalal stone arch bridge in Mesopotamia. Structural modeling of ancient bridge made of natural stone has been proven reliable, and accurate results have been obtained using 3D finite elements. Based on the more applicable theories of failure, a general methodology is presented for evaluating the ringstone of the largest ellipse-shaped arch of the Dalal Bridge. The elliptical arch was built in the COMSOL Multiphysics complex using 70 3D elements to represent the number of stones used along the length of the arch in the Dalal Bridge. Therefore, to create an accurate model, the coordinates of the four nodes of each stone were entered. Then, all domains were extruded for 0.8 m in the y-axis direction, i.e., 0.8 m of the bridge width was selected for investigation. That is, tapered fields were used to represent the stones of the arch ring. Using Rankine’s, St. Venant’s, and Haigh’s theories, the qualitative and quantitative characteristics of all components of the stresses and SED states are investigated. The maximum positive values of the principal stresses, σ1, σ2, and σ3, in the 3D model reach 1.4, 0.51, and 0.09 MPa, respectively, and their maximum negative values were 13, 6.8, and 3.4 MPa, respectively. The equivalent principal stresses determined via a 2D investigation did not exceed these values. Evaluating the ringstone against the maximum principal strain theory (i.e., St. Venant’s theory) reveals a safety factor of four in the existing state. Also, application of Haigh’s theory confirms the results of the previously applied approaches. Even though the safety of the arch, according to the total strain energy theory (i.e., Haigh’s approach), has been verified, a significant variation in the nonuniformity of the distribution of the SED (0.0011 J/m3–4416 J/m3) confirmed that the geometry of the investigated arch is not optimal for applied loading. The maximum value of the vertical component of the displacement is 3.4 mm, significantly lower than the allowable deflection for such an arch span.
8
Salam, Mahmood A., and Qiyao Wang. "Numerical Study on Bearing Capacity and Bulging of the Composite Stone Column." Open Civil Engineering Journal 15, no. 1 (March 17, 2021): 13–28. http://dx.doi.org/10.2174/1874149502115010013.
Анотація:
Background: In weak clay soil, a proper ground improvement technique using a stone column can be limited by the absence of sufficient lateral confining pressure. Stone columns should be strengthened to provide the minimum required lateral confining pressure. Objective: The aim of this study is to find out the significant improvement of the composite stone columns compared to the conventional stone columns by comparing the bearing capacity enhancement and the treated soil stiffness for both models. Composite stone columns with a solid concrete part at the top-head not only enhance the bearing capacity of the stone columns but also decrease the bulging failure and increase the surrounding soil stiffness. Methods: The 2D finite element analyses were carried out to simulate an experimental study conducted by Ambily and Gandhi on conventional stone columns. ABAQUS software program with the Mohr-Coulomb criterion for soft clay soil and stones was used in the simulation. First, a preliminary numerical model was created to simulate the experiment model. Similar material properties, boundary conditions, and constraints were considered in the preliminary model. The results were compared, and they were similar to the experimental results. During this process, the efficiency of the numerical model was confirmed. Second, the same numerical model was performed for the composite stone columns without modifying the material properties, boundary conditions, and constraints of the preliminary model. The parameters that influence the composite stone column bearing capacity as the length of the concrete part, the stress concentration ratio, and the shear strength of the surrounding soil, were all studied. Results: The data obtained from the aforesaid study was used along with ABAQUS software package. Compared to existing work, our approach achieves a significant correlation, and it indicates that the solid concrete part increases the surrounding soil stiffness, in addition to increasing the bearing capacity of the stone column. The solid concrete part resists bulging deformation by moving the bulging failure downward where the confining pressure is larger. The stress concentration ratio increases with the length of the solid concrete part. Conclusion: Composite stone columns have a significant influence on the improvement of weak clay soil and increase the bearing capacity of soil under superstructures. Furthermore, they also increase the stiffness of weak soil around the column. The magnitude of weak soil improvement by using composite stone columns is greater than conventional stone columns. Therefore, composite stone columns are more efficient and effective than conventional stone columns.
9
Boote, Scott, Mark Day, and Steve Webb. "Stone as a structural material. Part 4: Contemporary loadbearing stone buildings." Structural Engineer 98, no. 10 (October 1, 2020): 28–33. http://dx.doi.org/10.56330/fadl5301.
Анотація:
Not all contemporary innovation is about exploiting digital fabrication or creating wild new forms. By applying a new way of thinking to traditional materials and craft, geometrically simple and innovative structures can be realised that are both elegant and environmentally ethical. Webb Yates, in conjunction with The Stonemasonry Company, has begun to develop a building system that would be a low-energy alternative to more common steel and concrete-framed structures. In this article, we hope to demonstrate how a creative approach to engineering design can utilise stone to exploit its inherent strengths.
10
Boote, Scott, and Alex Lynes. "Stone as a structural material. Part 3: Post-tensioned stone structures." Structural Engineer 98, no. 8 (August 1, 2020): 22–28. http://dx.doi.org/10.56330/fzda2725.
Анотація:
To utilise stone’s high ratio of compressive to tensile strength to maximum effect, stone structures can be compressed using tensioned cables or bars. Post-tensioned stone increases the failure load of stone in bending, but also the stiffness of a structure by reducing joint cracking. This method of construction is widely used for concrete structures, but the advantages of using similar techniques with stone are only just being realised. This article covers the reasons for post-tensioning stone, the advantages of doing so, and presents a series of projects that demonstrate the evolution and development of our expertise and understanding at Webb Yates.
11
Laskaridis, K., and M. Patronis. "“KARYSTÍA LÍTHOS”: A TIMELESS STRUCTURAL ORNAMENTAL STONE." Bulletin of the Geological Society of Greece 43, no. 5 (July 31, 2017): 2475. http://dx.doi.org/10.12681/bgsg.11649.
Анотація:
Karystía Líthos (= Stone of Karystos) is a widely used structural material since archaic times. It has been used in various constructions, considered to date before 700 BC or before the Trojan War or even as early as the Neolithic Age. The term “Karystía Líthos”, mentioned by Strabo, Pliny et al., includes cipollino marble, slates etc. Their main mineralogical constituent is calcite and their colour depends on the secondary and accessory minerals. This paper examines the timelessness of Karystía Líthos, focusing on the determination of its physical - mechanical and aesthetic characteristics. The natural stone properties are classified into those characterizing the material, and those determining the suitability of the stone for various special uses. Those properties were determined according to Standard EN 12326-2 “Slate and stone products for discontinuous roofing and cladding - Part 2: Methods of test”. The results were statistically analyzed, in order to draw relevant practical conclusions. The physical - mechanical properties of Karystía Líthos, on which its endurance through time and under mechanical stresses is depending, and its aesthetics, render it a widely applied ornamental stone to-date.
12
McNeely, D. K., G. C. Archer, and K. N. Smith. "Structural analysis of old stone arch bridges." Canadian Journal of Civil Engineering 16, no. 6 (December 1, 1989): 789–97. http://dx.doi.org/10.1139/l89-122.
Анотація:
The use of stone arches for bridge construction has generally ceased, but since these structures still exist in modern road systems, their structural integrity is of current concern. This paper presents an analysis technique suited for the thick jointed heritage stone arch bridges found in Canada. The effect of increased mortar joint size on structural response is investigated. The response of a section to eccentric thrust is postulated and the effective section properties are derived. Structural behaviour proceeds from a fixed arch to a two-hinge, a three-hinge, and finally a five-hinge failure mode for a symmetrical arch with midspan loading. A typical load–deflection curve is developed, suitably adjusted for secondary effects due to changes in geometry and material nonlinearity. Stone arch bridges in Canada were constructed with thick mortar joints, which exhibit significant deterioration of stiffness with load eccentricity and, therefore, significant secondary effects; as thickness increases, ultimate strength decreases. A suitable limit states prediction for the load capacity of old stone arches is proposed. Key words: arch, bridge, heritage, limit states, stone, structural analysis.
13
Fiorentini, Nicholas, Jiandong Huang, Giacomo Cuciniello, Pietro Leandri, and Massimo Losa. "Comparing the Performance of Historical and Regular Stone Pavement Structures in Urban Trafficked Areas through the Finite Element Method (FEM)." Infrastructures 8, no. 7 (July 20, 2023): 115. http://dx.doi.org/10.3390/infrastructures8070115.
Анотація:
Stone pavement structures (SPS), also known as stone roads or stone-paved roads, are road pavements constructed using stones as the primary surface material. Different types of SPS exist; historically, irregular-shaped stones with downward protrusions have been often exploited since regular-shaped stones were difficult to be produced. More recently, regular cuboid stones can be also used. Accordingly, in new construction and renovations of SPS, pavement designers must take an essential decision concerning the adoption of historical or regular stones. Nonetheless, it is often confusing which of the two types of stones should be employed, considering that historical and regular SPS follow the same theory and pavement design methods. Therefore, a comparison between the performance of these two types of SPS is required to support their design and maintenance. Moreover, SPS are limitedly investigated and, to the best of our knowledge, there are no research contributions that address this specific task. Accordingly, in the present study, after conducting a laboratory characterization and in situ structural survey by Falling Weight Deflectometer (FWD) on a SPS, a comparative analysis based on the Finite Element Method (FEM) was carried out for investigating the structural performance of the historical (H-SPS) and regular SPS (R-SPS) in urban trafficked areas, where SPS must withstand heavy traffic loads. Specifically, considering both typologies of SPS, the paper aims to model and investigate: (a) the mechanical behavior under loading (displacements, stress, and strain distribution), (b) failure criteria (stone warpage and separation between the stones and the mortar joint), (c) the joint efficiency between stones, and (d) to which extent the road subgrade stiffness may influence the performance of SPS. In addition to the pavement design perspective, the research also provides a short glance at the strengths and weaknesses of R-SPS and H-SPS from other sides, such as functionality, ease of maintenance, construction techniques, and cultural and historical values.
14
Boote, Scott. "Stone as a structural material. Part 2: Traditional and reinforced stone stairs." Structural Engineer 98, no. 6 (June 1, 2020): 18–23. http://dx.doi.org/10.56330/igyh5338.
Анотація:
Since the construction of the first British example of a cantilever stone staircase (Inigo Jones’ ‘tulip’ staircase in Queen’s House in Greenwich, 1629–35), this technique has served as both grand statement and modest utility. The structural principles are now widely understood, but by adopting a creative approach to structural analysis, design and detailing, they can be combined and extrapolated to design and construct more refined structures in myriad applications.
15
Seras, Marco Antonio Navarrete, Francisco Javier Domínguez Mota, Elia Mercedes Alonso Guzmán, Wilfrido Martínez Molina, Hugo Luis Chávez García, José Gerardo Tinoco Ruiz, and José Alberto Guzmán Torres. "Scanning Electron Microscope in Rocks and their Comparison with Physical-Mechanical Properties." Key Engineering Materials 841 (May 2020): 114–18. http://dx.doi.org/10.4028/www.scientific.net/kem.841.114.
Анотація:
. Banks of stone materials from Michoacán, Mexico were characterized, since they are used in the construction of infrastructure in the area. With these materials are made hydraulic concrete mixtures or asphalt mixtures, foundations, paving stones and in restoration of historical monuments. The rocks analyzed and characterized, come from banks of volcanic stone materials and banks of crushed stone materials, which were subjected to mechanical tests such as uniaxial compression resistance (UCR), in addition was used scanning electron microscope (SEM), by means of which the characterization was carried out, obtaining morphological information of the material. The comparison of physical-mechanical properties with the elements they possess is important to estimate their behavior within ceramic matrices or as a structural element.
16
Ruffolo, Silvestro Antonio, Mauro Francesco La Russa, Natalia Rovella, and Michela Ricca. "The Impact of Air Pollution on Stone Materials." Environments 10, no. 7 (July 10, 2023): 119. http://dx.doi.org/10.3390/environments10070119.
Анотація:
Air pollution can have a significant impact on stone materials used in monuments, buildings, and sculptures. Sulfur and nitrogen oxides are particularly harmful pollutants, especially in carbonate stones. These oxides, reacting with moisture in the air, result in the formation of acids able to erode the stone surface and gradually compromise its structural integrity. The acids can also combine with airborne particulate matter, heavy metals, and salts, leading to the development of black crusts. These not only have detrimental effects on the stone’s integrity but also affect the original appearance of the surfaces, threatening the conservation of important monuments and buildings. This review discusses the characteristics of black crusts and their relation to the environment and stone materials.
17
Boote, Scott, and Alex Lynes. "Stone as a structural material. Part 1: Mechanical properties." Structural Engineer 98, no. 3 (March 1, 2020): 20–25. http://dx.doi.org/10.56330/vdxn2678.
Анотація:
Dimension stone has been employed as a structural material for thousands of years, but its use has declined in recent times. The loss of traditional skills and knowledge has led this once ubiquitous material to be perceived as expensive to quarry, cut and transport, being seen in the eyes of many as suitable only for cladding or flooring. Yet when paired with a modern approach to structural analysis, design and detailing, and a rigorous statistical analysis of material strengths, stone can realise its potential as a material fit for the 21st century. This set of four articles will explore the contemporary use of stone in a variety of structural applications, showcasing the versatility of this often overlooked material. Part 1 will discuss the mechanical properties of stone, with subsequent parts covering the use of plain, reinforced and post-tensioned stone in buildings and staircases.
18
Boote, Scott, and Alex Lynes. "Creativity in the New Stone Age Part 2 - Structural Stone in Staircases." IABSE Symposium Report 108, no. 1 (April 19, 2017): 110–13. http://dx.doi.org/10.2749/222137817821232793.
19
Eugene Gow, Jun Yi, and Pei Xuan Ku. "The Analysis of Stone Trapping in Tire Tread for Various Road Conditions." MATEC Web of Conferences 335 (2021): 03003. http://dx.doi.org/10.1051/matecconf/202133503003.
Анотація:
A tire tends to trap stones in its tread pattern when the vehicle is on a move and this might affects the tire balance due to uneven tread wear of tread portion. The study aims to simulate stone trapping performance under various tire tread patterns and road conditions as well as assessing the performance of tires with stones trapped. The stone trapping phenomena on different tire tread pattern were analyzed under dry and wet road conditions. The tire models chosen were the symmetrical tire, asymmetrical tire, and directional tire. The model of these tires, stone and a flat road surface were created using SolidWorks and Fusion360 software and the static structural simulation is performed by using finite element analysis method. Tire inflation analysis and steady state rolling analysis were conducted to evaluate three parameters: total deformation, Von-Mises stress and equivalent elastic strain of the tires. It found that all three parameters are higher when stone trapped in tire for all tread pattern types. Symmetrical tread pattern provides the least wear and tear since it has the lowest increment of maximum equivalent elastic strain in both road conditions. Stone trapping in tire grooves would impact on the lifespan of the tire.
20
Pandey, Suraj Prasad, Hua Yu, Chooikim Lau, and Kam Ng. "New Coal Char-Based Building Products: Manufacturing, Engineering Performance, and Techno-Economic Analysis for the USA Market." Sustainability 16, no. 5 (February 23, 2024): 1854. http://dx.doi.org/10.3390/su16051854.
Анотація:
Common building products, i.e., thin brick and stone veneer, add the look of brick walls or the enduring charm of natural stones into buildings and houses without imposing a substantial increase in structural load. This study investigates the mechanical strength, durability, and economic feasibility of producing innovative char-based thin bricks and stone veneers. The char-based thin brick vacuum treated with hydrophobic liquid exhibits water absorption rates within the 4–7% range, displays durability against 50 freeze–thaw (F-T) cycles, and maintains a saturation coefficient below 0.6. In contrast, commercial thin bricks have water absorption of 9–12%. Treated char-based stone veneer has water absorption of 5.3% and an average compressive strength of 19.2 MPa, maintains its structural integrity throughout 50 F-T cycles, and exhibits a negligible linear shrinkage of approximately 0.01%. In contrast, commercial stone veneers have water absorption of 10–16%. These engineering properties meet the criteria as per ASTM standards C1088 and C1670 for thin brick and stone veneer, respectively. A techno-economic study was preliminarily conducted to examine the potential cost efficiency and cash flow in manufacturing these char-based building products. The manufacturing cost of USD 25.83 is lower than the average market price of 64.65 USD/sq. m. for thin bricks. The manufacturing cost of USD 32.65 is lower than the average market price of 129.17 USD/sq. m. for stone veneers. These comparisons present a compelling economic advantage for their commercialization. This comprehensive study has demonstrated the advantages of sustainable char-based stone veneers and thin bricks regarding engineering performance and economic benefits.
21
Iordanidis, A., and J. Garcia-Guinea. "Analytical geochemistry in the service of medicine: An experimental study of urinary stones from Northern Greece." Bulletin of the Geological Society of Greece 47, no. 2 (January 24, 2017): 818. http://dx.doi.org/10.12681/bgsg.11118.
Анотація:
Knowledge of the precise human biomineral composition may allow physicians to recommend an appropriate prophylactic therapy for the patient and thus prevent or delay the stone recurrence. The present study focuses on the application of complementary analytical techniques to the characterization of human urinary stones. Several gallbladder and renal stone samples were obtained from patients dwelling in areas of northern Greece. A comprehensive analytical study took place, employing the following, common in analytical geochemistry, techniques: Environmental Scanning Electron Microscopy (ESEM) coupled to Energy Dispersive System (EDS), X-Ray Diffraction (XRD), thermogravimetry (TG), μRaman spectroscopy and Cathodoluminescence (CL). A detailed determination of morphological, micro-structural, molecular, chemical and mineralogical characteristics of the urinary stone samples was achieved. It was evident by our study the application of powerful analytical techniques could substantially help the medical advisors to ascribe a medical treatment of diseases related to stone formation.
22
Rippmann, Matthias, and Philippe Block. "Rethinking structural masonry: unreinforced, stone-cut shells." Proceedings of the Institution of Civil Engineers - Construction Materials 166, no. 6 (December 2013): 378–89. http://dx.doi.org/10.1680/coma.12.00033.
23
Fazil Marickar, Y. M., Luxmi Varma, and Peter Koshy. "Ultra structural study of laminated urinary stone." Urological Research 37, no. 5 (August 6, 2009): 289–92. http://dx.doi.org/10.1007/s00240-009-0210-8.
24
Hadi, Sz, and A. S. Kis. "Structural Analysis of Historical Cantilevered Stone Staircases." Journal of Applied Engineering Sciences 13, no. 2 (December 1, 2023): 197–206. http://dx.doi.org/10.2478/jaes-2023-0025.
Анотація:
Abstract This paper studies the behaviour of historical cantilevered stone staircases. In Transylvania these types of stairs are found mainly in buildings classified as historical monuments built until the 1920s. Understanding the behaviour of historical staircases is essential when proposing consolidation or restoration interventions in buildings. In this work, structural analyses on simple models of staircases made of stone elements are proposed in order to investigate the stiffness of the assembly, the stresses that appear in the elements, deformations, the influence of the railings in the overall behaviour and the simulation of the breaking of a single individual step. The types of staircases investigated in this paper are existing historical structures that currently are no longer built from scratch, so the purpose of the calculation is not to dimension but to verify the existing structure.
25
Brown, E. R., and John E. Haddock. "Method To Ensure Stone-on-Stone Contact in Stone Matrix Asphalt Paving Mixtures." Transportation Research Record: Journal of the Transportation Research Board 1583, no. 1 (January 1997): 11–18. http://dx.doi.org/10.3141/1583-02.
Анотація:
The use of stone matrix asphalt (SMA) has continued to rise in the United States because of its ability to withstand heavy traffic without rutting. This ability is derived from a stone-on-stone coarse aggregate skeleton. While this coarse aggregate skeleton is imperative for SMA to perform, no quantitative method exists to measure it. A method for determining when stone-on-stone contact exists is presented. The proposed method first determines the voids in the coarse aggregate (VCA) for the coarse aggregate–only fraction of the SMA mixture. Second, the VCA is determined for the entire SMA mixture. When the two VCA values are compared, the VCA of the SMA mixture should be less than or equal to the VCA of the coarse aggregate–only fraction to ensure that stone-on-stone contact exists in the mixture. Five different methods for determining the VCA of the coarse aggregate–only fraction were used to see which performed best and was the most practical. The aggregate degradation produced by each of the five methods was also determined and compared with the coarse aggregate breakdown produced in an SMA mixture compacted with 50 blows of a Marshall hammer. The results indicate that the Superpave gyratory compactor and dry-rodded methods produced the best results. Both methods are recommended for further testing.
26
Marzo, Carla, and Risale Neves. "Stereotomic Design: The Use of Stone in Contemporary Architecture." Key Engineering Materials 848 (June 2020): 165–73. http://dx.doi.org/10.4028/www.scientific.net/kem.848.165.
Анотація:
Stereotomy, as a constructive technique, has a millennial history that has been optimized over time due to the development of geometry and construction . Using mainly stones specially limestone the stereotomic design takes advantage of the subdivision of solid big structures into smaller different pieces, named ´voussoirs´. These pieces are limited in forms and they work through the assembly of multiple units to create the final structure. Precision in the cuts and the correct placement of each part is crucial to ensure static and structural safety. The development of digital technology which has been taking place through the last decades re-ignited the interest in the use of stones as an essential material to buildings structures. As a result, many experiences took place mixing the use of stones with computerized and manufactoring techniques that , in turn, boost the industry of stone cutting. This paper presents information on the use of stereotomic design through the centuries, focusing on its evolution as a technique and on the results that are showing out in contemporary architecture. Through an analysis of the recovery of stone as a constructive and structural material, it is the aim of this study to establish a general panorama on the results achieved in the field of architecture and design in order to understand the methodologies applied when using the stereotomic technique.
27
Coree, Brian, and Joe W. Button. "Full-Scale Rutting Tests of Large-Stone Asphalt Mixtures." Transportation Research Record: Journal of the Transportation Research Board 1590, no. 1 (January 1997): 62–72. http://dx.doi.org/10.3141/1590-08.
Анотація:
Repetitive loaded-wheel tests were conducted on three large-stone mixtures: (a) a dense mixture designed using a new method that guarantees stone-on-stone contact, (b) a dense mixture designed to exhibit poor stone-on-stone contact, and (c) an open-graded mixture commonly used by the Indiana Department of Transportation (INDOT). All three mixtures had 38-mm (1.5-in.) nominal maximum size aggregate. Test pads 76-mm (3-in.) thick, 1.5-m (5-ft) wide, and 6.1-m (20-ft) long were constructed by a local contractor using a batch plant, a conventional paver, and a static steel wheel roller. No serious difficulties were experienced during placing or compacting the mixtures. The compacted surfaces were quite rough due to the large particle sizes. This rough texture apparently introduced significant variability in the density of the compacted test pads. The finer mixture designed to have poor stone-to-stone contact gave the highest density. Five thousand repetitions of a 4082-kg (9,000-lb) force were applied to each pavement through dual truck tires inflated to 620 kPa (90 psi). Cross-section profiles were measured periodically throughout testing. Rut depths measured in the mixture designed using the new design (Texas coarse) were significantly less than those in the other two mixtures. The mixture made purposely with poor stone-on-stone contact (Texas fine) exhibited the highest rut depths, which were similar to those measured in conventional binder coarses in the INDOT data base. This indicates that large stones floating in a matrix of conventional mix will have little effect on resisting rutting. The INDOT No. 2 open-graded mixture exhibited more rutting than the Texas coarse mixture but less than the Texas fine mixture. The use of this open-graded mixture as a surface coarse may have allowed unnatural displacement of large aggregate near the surface at the sides of the applied loads, which contributed to greater-than-expected rut depths.
28
Boote, Scott, Alex Lynes, Steve Webb, and Mark Day. "Creativity in the New Stone Age Part 1 - Structural Stone in Contemporary Structures." IABSE Symposium Report 108, no. 1 (April 19, 2017): 106–9. http://dx.doi.org/10.2749/222137817821232838.
29
Schwartzbach, A., JW Behrens, and JC Svendsen. "Atlantic cod Gadus morhua save energy on stone reefs: implications for the attraction versus production debate in relation to reefs." Marine Ecology Progress Series 635 (February 6, 2020): 81–87. http://dx.doi.org/10.3354/meps13192.
Анотація:
Reefs are structurally complex habitats that are degraded in numerous coastal areas. Structural complexity is often associated with elevated fish abundance, and recent studies have indicated that such structural complexity (e.g. reefs) not only acts as a fish aggregator, but also increases fish production. The objective of this study was to advance this knowledge by investigating if an underlying mechanism of the observed productivity is related to reduced metabolic rates (proxy for energy use) of fish in reef habitats. Using juvenile Atlantic cod Gadus morhua, we tested the hypothesis that fish energy use differs between fish occupying stone reef and sand bottom habitats. Metabolic rate (MO2) was estimated using intermittent flow respirometry in simulated stone reef and sand bottom habitats over 24 h. Results revealed that G. morhua in the stone reef habitat exhibited significantly reduced accumulated MO2 compared to G. morhua in the sand bottom habitat. Likewise, there was a tendency for lower mean standard metabolic rates of the fish in stone reefs, although this pattern was not statistically significant. There are many mechanisms that may underpin elevated productivity in structurally complex habitats such as reefs, including better access to shelter and increased food availability. Our study adds to these mechanisms by showing that G. morhua save energy when occupying stone reefs as compared to sandy bottoms, energy which may be allocated to somatic and gonadal growth.
30
Qi, Shunshun, Gouyu Li, Dun Chen, Mingtang Chai, Yu Zhou, Qingsong Du, Yapeng Cao, Liyun Tang, and Hailiang Jia. "Damage Properties of the Block-Stone Embankment in the Qinghai–Tibet Highway Using Ground-Penetrating Radar Imagery." Remote Sensing 14, no. 12 (June 20, 2022): 2950. http://dx.doi.org/10.3390/rs14122950.
Анотація:
The block-stone embankment is a special type of embankment widely used to protect the stability of the underlying warm and ice-rich permafrost. Under the influence of multiple factors, certain damages will still occur in the block-stone embankment after a period of operation, which may weaken or destroy its cooling function, introducing more serious damages to the Qinghai–Tibet Highway (QTH). Ground-penetrating radar (GPR), a nondestructive testing technique, was adopted to investigate the damage properties of the damaged block-stone embankment. GPR imagery, together with the other data and methods (structural characteristics, field survey data, GPR parameters, etc.), indicated four categories of damage: (i) loosening of the upper sand-gravel layer; (ii) loosening of the block-stone layer; (iii) settlement of the block-stone layer; and (iv) dense filling of the block-stones layer. The first two conditions were widely distributed, whereas the settlement and dense filling of the block-stone layer were less so, and the other combined damages also occurred frequently. The close correlation between the different damages indicated a causal relationship. A preliminary discussion of these observations about the influences on the formation of the damage of the block-stone embankment is included. The findings provide some points of reference for the future construction and maintenance of block-stone embankments in permafrost regions.
31
Sarli, Leopoldo, Matteo Gafa', Ernesto Longinotti, Fabio Carreras, Nicola Pietra, Anacleto Peracchia, Claudio Dotti, and Simonetta Cavalier. "Cholesterol Microlithiasis: Bacteriology, Gallbladder Bile and Stone Composition." HPB Surgery 1, no. 4 (January 1, 1989): 283–95. http://dx.doi.org/10.1155/1989/80465.
Анотація:
It is not known whether microcalculi possess structural differences compared with larger stones or whether they represent simply an earlier stage in stone disease.We carried out a controlled study on 10 patients affected by gallbladder cholesterol microlithiasis (CM). In all patients, samples from all parts of the stones were studied by X-ray diffraction and by infrared spectrophotometry. Bile analysis was carried out to determine cholesterol, phospholipid and total bile acid content. The cholesterol saturation indices (C.S.I.) were calculated. In all samples, bacterial bile culture was carried out. The results were compared with those of 10 patients who had undergone cholecystectomy for large cholesterol stones, and for 10 patients who had undergone abdominal surgery but without biliary pathology. Patients in these latter groups were matched with the first according to sex and age.Microcalculi proved to be layered (nucleus and external layer) in only 2 cases and larger stones in 9; cholesterol was seen to be the principal crystalline component in all cases. Traces of bilirubin were found in 7 CM and in the nuclei of 5 larger stones.These results show that the structural composition of microcalculi is similar to that of the nucleus of larger stones. No substantial differences exist, however, between the two groups of patients regarding the other parameters taken into consideration.
32
Öztürk, Çetin. "Physicochemical properties of heat treated sille stone for ceramic industry." Open Chemistry 16, no. 1 (November 27, 2018): 1134–42. http://dx.doi.org/10.1515/chem-2018-0122.
Анотація:
AbstractTraditional building stones may be defined as the rocks continuously and commonly used throughout the history of a given town or region. Sille stone bears volcanic and andesitic features, which are unique to the Sille region (Konya) and its surroundings. Sille was a historical and cultural settlement in the Neolithic Age. The high silica content of Sille stone is an important building material due to its easy workability and durability properties. The Sille stone, which is generally used as a floor and wall covering, has many artifacts ranging from the Ottoman and Seljuk periods to the present day.This work is aimed to determine the structural characteristics of Sille Stone, which still preserves its architectural value, and to reveal its potential of being used as an alternative material in the ceramic industry. For this purpose, chemical, physical and thermal properties of Sille Stone were determined in this investigation. The results indicate that the physical properties of Sille Stone are similar to industrial ceramic tiles, and it can be used as a ceramic material after a heat treatment or a surface coating application as this will prevent soluble salts from escaping that are contained in the porous structure and which can have harmful effects.
33
Fallatah, Marwah, Rafaa Jaafari, Aryaf Alshammari, Abdulrahman Bashaikh, Israa Alshehri, Hassan AlSubaie, Mooza Alabbasi, et al. "Imaging of Kidney Stones: CT Urography, Ultrasound, and Stone Composition Analysis." Journal of Healthcare Sciences 3, no. 12 (2023): 594–99. http://dx.doi.org/10.52533/johs.2023.31206.
Анотація:
Kidney stone disease, prevalent since ancient times, affects around 12% of the global population, with a higher incidence in males. Recurrence is common, and the formation of stones is influenced by genetic, metabolic, environmental, and structural factors. Ultrasonography, as the initial diagnostic tool, is noninvasive and radiation-free, making it suitable for initial evaluations. However, for more precise diagnosis, especially in complex cases, CT scans, including Dual Energy CT (DECT), are preferred due to their higher accuracy. This review also delves into the historical evolution of diagnostic methods, from the once-popular Intravenous Urography (IVU) to the advanced DECT, which offers detailed insights into stone composition. While each imaging modality has its advantages and limitations, CT scans remain the gold standard for their comprehensive analysis capability. The choice of imaging technique is influenced by factors such as stone size, patient characteristics, and clinical context. This review underscores the importance of personalized strategies in selecting the most suitable imaging modality for effective diagnosis and management of kidney stone disease.
34
Nunes, Cristiana Lara, Kateřina Mlsnová, and Zuzana Slížková. "Limewashes with Linseed Oil and Its Effect on Water and Salt Transport." Buildings 12, no. 4 (March 25, 2022): 402. http://dx.doi.org/10.3390/buildings12040402.
Анотація:
Paints are the protective and aesthetic skin of buildings, so (re) painting is one of the most recurrent maintenance actions. Limewashes have been used since antiquity and are currently of high interest for both conservation and new construction, majorly thanks to their eco-friendly and antiseptic features, and ability to improve the performance of the materials in relation to water transport. Linseed oil is a traditional water-repellent additive that can enhance the water-shedding properties of the limewashes. However, it has the risk of altering the drying kinetics of the substrate if an improper dosage is used. In this work, limewashes with the addition of varying dosages of linseed oil have been applied on two types of natural stone to study the effect of the paints in respect to water and salt transport. The water absorption by capillarity was reduced in both stones coated with pure limewash and limewash with oil, while the drying rate was slightly accelerated. The effect of the paints on the drying of the salt-laden stones varied. The salt damage developed during drying also diverged in both stones, damaging the coats and stone surface of the less porous stone and mainly promoting salt efflorescence in the most porous one.
35
Park, Y. S., J. Y. Kim, S. I. Hong, D. M. Kim, Sung Jin Jung, and H. S. Kim. "Structural Behavior Analysis of Masonry Stone Pagoda Considering the Inner Construction Types of Stylobate." Advanced Materials Research 133-134 (October 2010): 515–18. http://dx.doi.org/10.4028/www.scientific.net/amr.133-134.515.
Анотація:
We have many difficulties in the modeling and analysis of masonry stone pagoda structure because this structure has the discontinuum behavior characteristics, compared with the general continuum structures. Also, we need to consider the inner construction types of stylobate for the reasonable analysis of structural mechanism of masonry stone pagoda. Most masonry stone pagoda structures built in Korea are largely classified into three parts such as top part, body part and stylobate. Specifically, the stylobate takes a very important structural part, performing the role of foundation in ordinary structures, and the reduction of stylobate’s bearing capacity has great influence on the safety of structure. As for stylobate, the construction types of inner Jeoksim result in the different structural behaviors. Therefore, this study selects three-story stone pagoda in Goseon-sa temple site that shows the typical type of stone pagoda structure in Korea. Also, this study investigates the construction types of stylobate and evaluates the structural and mechanical behaviors of masonry stone pagoda structure according to many application variables of stylobate’s Jeoksim forms. To this end, we considers the contact surface and block modelling for the discontinuum elements through the discrete element method and finite element method. Through the comparison of analysis results, we can find out the load transfer mechanism according to the inner Jeoksim types of stylobate.
36
Strokin, K., D. Novikov, V. Konovalova, and N. Kasiyanenko. "CHANGES IN THE STRUCTURAL AND PHASE COMPOSITION OF CEMENT CONCRETE DURING MICROBIOLOGICAL CORROSION." Bulletin of Belgorod State Technological University named after. V. G. Shukhov 6, no. 11 (August 18, 2021): 106–13. http://dx.doi.org/10.34031/2071-7318-2021-6-11-106-113.
Анотація:
The article considers the change in the structural and phase composition of cement stone made of Portland cement of the CEM I 42.5 N brand in the process of bacterial and fungal corrosion during 6 months when humidified. The X-ray images of cement stone show peaks that characterize the non-hydrated components of Portland cement alite, belite, tricalcium aluminate, four-calcium aluminoferrite and gypsum. By the method of X-ray phase analysis, it is found that during microbiological corrosion, the content of all phases of cement stone decreases. The aspergillus niger van Tieghem fungi have a stronger effect on the structural and phase composition of cement stone. Fungal microorganisms destroy the crystalline phases and absorb amorphous phases – calcium hydrosilicates C-S-H (I) and C-S-H (II) and tobermorite. When bacteria Bacillus subtilis affects the cement stone, the content of the calcite phase increases, which is a product of corrosion, while the action of black mold reduces the intensity of CaCO3 peaks. A decrease in the content of low-base calcium hydrosilicates and ettringite, as well as other crystalline phases, leads to a decrease in the compressive strength of the cement stone. During 6 months of microbiological corrosion of cement concrete under conditions of constant wetting, the compressive strength decreases by about 35 %.
37
Павлов, Валерий Вадимович, and Евгений Владимирович Хорьков. "STRUCTURAL SOLUTIONS FOR STRENGTHENING DAMAGED STONE ARCH STRUCTURES." Housing and utilities infrastructure, no. 4(19) (December 22, 2021): 9–18. http://dx.doi.org/10.36622/vstu.2021.19.4.001.
Анотація:
Рассмотрены исторические аспекты возникновения каменных арочных конструкций перекрытий, материалы, которые использовались для их возведения в различные исторические периоды, классификация арочных конструкций, а также основные конструктивные решения и технологические аспекты их возведения. Приведены результаты работ, выполненных по определению численных значений геометрических параметров и обследованию технического состояния арочных конструкций зданий старой постройки, расположенных в центральной (исторической) части г. Казани. Приведены результаты исследования работ других авторов по определению наиболее часто встречающихся дефектов и повреждений в арках, а также причины их возникновения. Рассмотрены технические решения различных авторов по усилению арочных конструкций, с использованием различных материалов, в том числе и композитными материалами на основе однонаправленных углеродных волокон. Описана область применения и изложены технические решения, разработанные авторами статьи для усиления арочных конструкций, которые учитывают особенности их конструктивных решений и повреждений. We considered the historical aspects of the emergence of stone arched structures of ceilings, the materials used for their construction in various historical periods, the classification of arched structures, as well as the main design solutions and technological aspects of their construction. We present the results of the work performed to determine the numerical values of geometric parameters and to survey the technical condition of arched structures of old buildings located in the central (historical) part of Kazan. As well we demonstrate the results of a study of the works of other authors to determine the most common defects and damages in arches and the causes of their occurrence. We show the technical solutions of various authors to strengthen arched structures using various materials, including composite materials based on unidirectional carbon fibers. We describe the scope of application and outline the technical solutions developed by the authors of the article for strengthening arched structures that take into account the features of their design solutions and damages.
38
Heyman, Jacques, and J. H. Lienhard. "The Stone Skeleton: Structural Engineering of Masonry Architecture." Journal of Applied Mechanics 63, no. 4 (December 1, 1996): 1056. http://dx.doi.org/10.1115/1.2787238.
39
Firdolas, Fatih, Tankut Ates, Niyazi Bulut, and Omer Kaygili. "Thermal and structural characterization of the kidney stone." Journal of Thermal Analysis and Calorimetry 139, no. 6 (November 15, 2019): 3843–46. http://dx.doi.org/10.1007/s10973-019-09042-6.
40
Kotoulas, L., L. Melidis, I. Giannaris, E. Stylianidis, K. Katakalos, and G. Manos. "STRUCTURAL ASSESSMENT OF STONE-ARCH BRIDGES THROUGH PHOTOGRAMMETRY." International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLVIII-M-2-2023 (June 24, 2023): 879–84. http://dx.doi.org/10.5194/isprs-archives-xlviii-m-2-2023-879-2023.
Анотація:
Abstract. The present study examines the structural assessment of Pashas bridge, located at the Western Makedonia, in Greece. This stone arched bridge, which is declared cultural heritage monument, was built during the end of 17th century and it was destructed during the 2nd civil war, in 1941 by British and New Zealander soldiers aiming to end the German invasion to the South of Greece. It was considered the largest bridge in Macedonia, with a length of more than 100 meters, 6 arches, the biggest one of which was almost 15 meters high. In its current form it is partially collapsed.
41
Sorace, S. "Creep in Building Stones Under Tensile Conditions." Journal of Engineering Materials and Technology 118, no. 4 (October 1, 1996): 456–62. http://dx.doi.org/10.1115/1.2805942.
Анотація:
Careful structural analyses of ancient stone constructions methodically showed crack openings under tensile stresses notably lower than the corresponding strength limits. Based on this observation, an experimental research was undertaken aimed at determining the mechanical effects related to permanent loading in time. The results of a first series of long-term tension and bending tests conducted on four natural building stones are presented in this paper. A time-delayed response analogous to the creep behavior of several geomaterials as well as of metals and ceramics was found; the response was then suitably described by the same analytical models usually applied to these last material classes. However, the stone building materials are characterized by a notably higher strength decay taking place in short times which confirmed the trend already shown by the structural studies. A thorough damage analysis developed with reference to the tertiary creep phase revealed both the physical and phenomenological correspondence of the adopted Kachanov-Rabotnov rule to the actual mechanical degradation time-progress.
42
Worcester, E. M. "Urinary calcium oxalate crystal growth inhibitors." Journal of the American Society of Nephrology 5, no. 5 (November 1994): S46. http://dx.doi.org/10.1681/asn.v55s46.
Анотація:
Calcium stones occur because renal tubular fluid and urine are supersaturated with respect to calcium oxalate and phosphate. The process of stone formation includes crystal nucleation, growth, aggregation, and attachment to renal epithelia. Urine contains macromolecules that modify these processes and may protect against stone formation. Attention has focused especially on inhibitors of crystal growth, and several have been isolated from urine, including nephrocalcin, an acidic phosphorylated glycoprotein that contains several residues of gamma-carboxyglutamic acid per molecule; osteopontin (uropontin), a phosphorylated glycoprotein also found in bone matrix; uronic acid-rich protein, which contains a covalently bound glycosaminoglycan residue; and several others. Abnormalities in structure and/or function have been detected in some of these proteins in stone formers' urine. However, the overall ability of urinary macromolecules to inhibit calcium oxalate crystal growth is often normal in stone formers. Recently, attention has been focused on the ability of these molecules to inhibit other stages in stone formation. Nephrocalcin can inhibit crystal nucleation, for example, and both nephrocalcin and Tamm-Horsfall protein inhibit crystal aggregation. Nephrocalcin and Tamm-Horsfall protein from stone formers are less active in preventing aggregation, and under some conditions, Tamm-Horsfall protein may promote the formation of crystal aggregates, especially in the presence of high concentrations of calcium. The structural abnormalities responsible for impaired inhibitory activity are not completely understood.
43
Liang, Pengfei, Yu Yang, Houxu Huang, Jiashun Liu, and Ning Guo. "Experimental Study on Fractal Characteristics of Particle Size Distribution by Repeated Compaction of Road Recycling Crushed Stone." Applied Sciences 12, no. 20 (October 13, 2022): 10303. http://dx.doi.org/10.3390/app122010303.
Анотація:
In order to investigate the compaction characteristics of graded crushed stone under repeated utilization, it is necessary to improve the utilization rate of road recycling crushed stone and maintain its strength and stability during recycling. In the present study, repeated compaction characteristic curves of graded crushed stone were developed using repeated compaction and screening of the graded crushed stone. The correlations between the fractal dimension of particle size distribution and repeated compaction times, water content, and dry density were analyzed. The experimental results indicate that both the maximum dry density and the optimal water content increase as the repeated compaction times increase. The fractal dimension of the particle size distribution of the graded crushed stone used in this test is 2.33 to 2.57. The obtained results show that as the fractal dimension increases, the maximum dry density of the graded crushed stone increases. At a constant repeated compaction time, the fractal dimension of the particle size distribution of graded crushed stone increased and then decreased as the water content increased. In summary, the compaction performance of the structural layer of graded crushed stone can be tuned by adjusting the fractal dimension of the particle size distribution of the recycled pavement structural layer in practical applications. Moreover, the optimal graded materials can be prepared under the guidance of the fractal dimension, thereby achieving an optimized working performance of the recycled pavement structural layer.
44
Tsampali, Evangelia, Stamatios Amanatiadis, Georgios Karagiannis, and Maria Stefanidou. "Inspecting the healing process in an artificial stone used for repair works containing crystallines." Technical Annals 1, no. 1 (December 22, 2022): 152–62. http://dx.doi.org/10.12681/ta.32160.
Анотація:
Stone has been a basic building material of different monuments and structural components such as foundations and masonry. At the same time, dif-ferent types of stones have been used for decorative architectural elements, such as cornices, reliefs, colonnettes, and corbels. The maintenance of stone ele-ments is essential for the continuity of these structures. Many studies have been performed to produce stones with artificial materials. This study aims to present a new approach to artificial stone with self-healing capability. Crystallines have been implied in two different dosages: 0.8 and 1.6% w./w, to achieve this goal. The addition of the crystalline admixtures affected the physical properties, de-creasing the porosity and the capillary absorption, proving the sealing properties of the admixtures. The self-healing efficiency has been tested with the sorption test, recovery of compressive strength, and 3D acoustic microscopy. The crys-talline admixtures accelerate the self-healing, increasing the sealing efficiency by 20% and recovering compressive strength by 15%. The analysis by 3D to-mography provided results that confirm the healing of the crack hasn't occurred only on the surface but extended to a certain depth.
45
Li, Zhiqing, Feng Hu, Shengwen Qi, Ruilin Hu, Yingxin Zhou, and Yawei Bai. "Deformation Characteristics of the Shear Zone and Movement of Block Stones in Soil–Rock Mixtures Based on Large-Sized Shear Test." Applied Sciences 10, no. 18 (September 17, 2020): 6475. http://dx.doi.org/10.3390/app10186475.
Анотація:
Soil–rock mixtures (SRM) have the characteristics of distinct heterogeneity and an obvious structural effect, which make their physical and mechanical properties very complex. This study aimed to investigate the deformation properties and failure mode of the shear zone as well as the movement of block stones in SRM experimentally, not only considering SRM shear strength. The particle composition and proportion of specimens were based on field samples from an SRM slope along national highway 318 in Xigaze, Tibet. Shear zone deformation tests were carried out using an SRM-1000 large-sized geotechnical apparatus controlled by a motor servo, considering the effects of different stone contents by mass (0, 30%, 50%, 70%), vertical pressures (50, 100, 200, 300, and 400 kPa), and block stone sizes (9.5–19.0, 19.0–31.5, and 31.5–53.0 mm). The characteristics of the shear zone deformation and block stone interactions were monitored by placing aluminum wires and dry ash in holes in the specimens. The results showed that the stone content 30% and 70% were two critical thresholds to determine the deformation characteristics of SRM. Under the conditions of high stone content and large particle size, the stones throughout the shear surface tended to extrude and roll during the shear process. The block stones around the shear surface were mainly affected by dilatancy and exhibited extrusion, particle breakage, and redistribution. The deformation pattern could be considered as be analogous to push-type shear deformation from the back to front or composite shear deformation from the front and back to the middle of the slope. It is of great importance to study the shear characteristics and deformation evolution of SRM to understand the progressive shear process of the sliding zone and the failure mode of landslides.
46
Tandel, Yogendra K., Chandresh H. Solanki, and Atul K. Desai. "3D FE Analysis of an Embankment Construction on GRSC and Proposal of a Design Method." ISRN Civil Engineering 2013 (March 7, 2013): 1–11. http://dx.doi.org/10.1155/2013/348973.
Анотація:
Stone column is often employed for strengthening of an embankment seated on deep soft clay. But in very soft clay having undrained shear strength less than or equal to 15 kPa, stone column may not derive adequate load carrying capacity and undergo large lateral deformation due to inadequate lateral confinement. In such circumstances, reinforcement to individual stone column by geosynthetics enhances load carrying capacity and reduces lateral deformation. This paper addresses parametric study on behaviour of embankment resting on Geosynthetic Reinforced Stone Column (GRSC) considering parameters such as stone column spacing to diameter ratio, deformation modulus of stone column material, geosynthetic stiffness, thickness of soft clay, and height of embankment by 3D numerical analysis. Finally, equation for Settlement Improvement Factor (SIF), defined as ratio between settlement of embankment without treatment and with geosynthetic reinforced stone column, is proposed that correlates with the major influence parameters such as stone column spacing to diameter ratio, deformation modulus of soft clay, and geosynthetic stiffness.
47
Artemov, Arseny O., Michael N. Ignatov, and Anna M. Ignatova. "Influence of Structural Components on Strength Properties of Silicate Stone Casting Materials during Controlled Crystallization." Solid State Phenomena 265 (September 2017): 1148–51. http://dx.doi.org/10.4028/www.scientific.net/ssp.265.1148.
Анотація:
Study and description of positive effect influence of Cr2O3 catalyst in controlled crystallization technology for production of stone casting silicate materials are provided. The introduction of heat treatment method that influences the forming of the structural components of produced material. The basis of manufacturing stone casting silicate materials is controlled crystallization of silicate melt that is organized in such a way that nucleation occurs within the melt and the final product has a fine grain structure. The structural components of silicate stone casting materials and their influence on strength properties are determined. The strength of stone casting silicate materials is the reduction in the difference in the temperature coefficients of linear expansion of crystal phases and residual glass phase.
48
Semko, O., N. Pinchuk, and D. Usenko. "RELIABILITY ASSESSMENT OF STONE STRUCTURES." Municipal economy of cities 4, no. 178 (September 4, 2023): 87–91. http://dx.doi.org/10.33042/2522-1809-2023-4-178-87-91.
Анотація:
The article provides valuable information on methods for assessing the reliability of stone structures. The authors draw attention to the issues of diagnostics and calculation of the reliability of existing masonry structures, and also offer methods for determining the compressive strength of masonry using the theory of reliability. The destructive and non-destructive tests underlying the determination of strength masonry are also described. The authors emphasize the importance of structural safety and reliability, which depend on many factors, including the type and magnitude of loads and the bearing capacity of structural elements. A sufficient state of safety is ensured by compliance with the relevant standards and regulations. The article draws attention to the importance of carrying out tests and calculations in the reconstruction and repair of buildings in order to guarantee their safe operation. The authors note that the safety and reliability of the design also depends on compliance with the rules and regulations that take into account the social, economic and environmental consequences of failure. The emphasis on the probabilistic approach to assessing the reliability of a design is an important aspect of the article. Taking into account the probability of failure allows us to develop a rational approach to the repair and reconstruction of buildings, ensuring their normal operation. The authors also draw attention to the importance of determining the probability of failure (Pf) as a fundamental parameter for its assessment. Keywords: reliability assessment, masonry structures, masonry strength, structural safety, safety factors, deformations, fire resistance, reliability theory, failure probability.
49
Block, Philippe, Tom Van Mele, Andrew Liew, Matthew DeJong, David Escobedo, and John Ochsendorf. "Structural design, fabrication and construction of the Armadillo vault." Structural Engineer 96, no. 5 (May 1, 2018): 10–20. http://dx.doi.org/10.56330/ysxl7244.
Анотація:
The Armadillo vault, exhibited at the 2016 Venice Architecture Biennale and commended at the 2017 Structural Awards, is a doubly curved, unreinforced, cut-stone, compression-only vault, constructed from 399 limestone blocks. The thickness of the stone varies from 8–12cm at the supports to 5cm at the peak. With a height of 4.4m and spans of over 15m, the structure has a thickness-to-span ratio half that of an eggshell. This paper describes the form-finding process and detailed structural analysis. Steel supports were designed to take the reaction thrusts of the vault and transfer them safely to both the ground and the internal steel tie system. The stone-cutting process for the limestone is also outlined, describing the rough-finished inner surface, which was patterned to follow lines of internal force flow, and the smooth flat outer surface. Finally, the process of erecting the formwork and falsework on site is also set out, including the process of decentring and the use of custom keystones.
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Tandel, Y. K., C. H. Solanki, and A. K. Desai. "Laboratory Experimental Analysis on Encapsulated Stone Column." Archives of Civil Engineering 59, no. 3 (September 1, 2013): 359–79. http://dx.doi.org/10.2478/ace-2013-0020.
Анотація:
Abstract The application of stone column technique for improvement of soft soils has attracted a considerable attention during the last decade. However, in a very soft soil, the stone columns undergo excessive bulging, because of very low lateral confinement pressure provided by the surrounding soil. The performance of stone column can be improved by the encapsulation of stone column by geosynthetic, which acts to provide additional confinement to columns, preventing excessive bulging and column failure. In the present study, a detailed experimental study on behavior of single column is carried out by varying parameters like diameter of the stone column, length of stone column, length of geosynthetic encapsulation and stiffness of encapsulation material. In addition, finite-element analyses have been performed to access the radial deformation of stone column. The results indicate a remarkable increase in load carrying capacity due to encapsulation. The load carrying capacity of column depends very much upon the diameter of the stone column and stiffness of encapsulation material. The results show that partial encapsulation over top half of the column and fully encapsulated floating column of half the length of clay bed thickness give lower load carrying capacity than fully encapsulated end bearing column. In addition, radial deformation of stone column decreases with increasing stiffness of encapsulation material.