Stone Structures Research Articles

Bioinspired multi-functional modified PVDF membrane for efficient oil-water separation

The pervasive issue of oily wastewater presents a critical environmental challenge, necessitating the development of advanced membranes that offer high purification efficiency, durability, and versatility. In this study, we introduce a novel bioinspired multifunctional membrane, synthesized by modifying polyvinylidene fluoride (PVDF) with fibrous two-dimensional carbides and nitrides (MXene) and silica (SiO2) nanoparticles, drawing inspiration from the complex structure of coral stones. The membrane was fabricated using the phase inversion technique, producing a robust material that achieves over 99% separation efficiency for oil–water mixtures. Beyond oil–water separation, the membrane exhibited exceptional performance in removing various contaminants from complex oily wastewater, including heavy metals, dyes, and phenol. Remarkably, the membrane maintained its high purification efficiency even after 5 consecutive cycles of oil–water separation and pollutant adsorption. This bioinspired multifunctional modified PVDF (MMP) membrane represents a major advancement in wastewater treatment technology, with significant potential for widespread application in the purification of complex oily wastewater.

Degradation of Concrete Cement Stone Under the Influence of Aspergillus niger Fungi

The concepts of physical and chemical transformations occurring in cement concrete under conditions of microbiological deterioration can be used to control the processes of the destruction of cement concretes in order to ensure the required durability and to predict the service life of products. The study of changes in the structural and phase composition of cement stone made of Portland cement grade CEM I 42.5N in the process of fungal deterioration for 6 months when moistened, as well as a sample of a concrete wall exposed to fungal microorganisms for 20 years, was carried out. Diffractograms of the studied cement stone samples contain a large number of pronounced narrow peaks and indicate a highly crystalline structure of phases with the presence of an X-ray amorphous phase of calcium hydrosilicates and tobermorite gel in the cement stone. Changes in the structure of cement stone under the influence of fungi are confirmed by the data of a derivatographic analysis. A decrease in the content of calcium hydrosilicates and ettringite, as well as other crystalline phases in cement stone, leads to a decrease in compressive strength by about 15% over 6 months of fungal degradation. Similar changes after 20 years of exposure to microorganisms suggest deterioration in the strength characteristics of concrete.

A glimpse into daily life in an Ottoman harbour: Evidence from a cesspit in Ainos (Türkiye)

The daily life of non-elite people from the past is usually hard to evaluate, since historical sources largely concentrate on the upper classes. This knowledge can be gained by archaeological excavations and use of geo- and bioarchaeological methods. In 2021, geophysical prospections in Enez (Türkiye) revealed a circular stone structure. The excavators identified a latrine probably used from 17th until the 19th century. Palynological, palaeoparasitological and archaeobotanical methods have been applied for understanding the diet, hygiene and diseases of the people using the latrine. The cesspit was a closed round structure with walls made of stones. It had no contamination from outside and was filled with liquid or semi-liquid content with dissolved salts and organic matter derived from urine, faeces, kitchen waste, dung and other rubbish. Results show a broad diet including wheat, chili peppers, olives, spices, a wide range of fruits, meat, fish and oysters. This sanitation did not protect the inhabitants of the house from intestinal parasites in the forms of helminths whipworm, roundworm and the protozoan Giardia duodenalis that causes diarrhoea. The data highlight the special role played by the harbour of Ainos in the establishment and possible expansion of new food products from the New World.

Landscape positioning of Neolithic mustatil stone structures along the margins of the Nefud Desert, Saudi Arabia

Monumental rectangular stone structures called mustatils are an important emerging feature of the Holocene archaeological record of northwestern Arabia. To date, few have been excavated, with available radiocarbon dates suggesting an age range of ca. 5400–4200 BC. Here we present a rigorous spatial analysis to identify the patterning and landscape context of 169 mustatils in the southern and western margins of the Nefud Desert. This included: (1) a systematic survey of satellite imagery to identify mustatils; (2) viewshed analysis to examine location and landscape visibility; (3) a point process model to understand how diverse environmental and landscape variables affect mustatil locations; (4) mark correlation function to assess spatial patterning of mustatils based on their size. Results indicate that mustatil locations are determined most by proximity to water (likely locations of enhanced surface water occurrence under the enhanced humidity of the Mid-Holocene), on east facing slopes, close to rocky areas, at elevations between 880 and 950 masl, and on or near topographic ridges (positive topographic position index). Viewshed analysis showed that mustatils are preferentially located in areas that have good views, but not the best that are available, indicating complex landscape positioning that balances a range of topographic and behavioural factors. Using a rank permutation method with size (length) of mustatils as a proxy for labour mobilization we show that mustatils within clusters are not arranged hierarchically based on size, and were likely built by non-stratified groups of people. Our analyses show that people were choosing multiple factors when deciding where to build mustatils, and that the distribution of mustatils may relate to different groups of people resulting in the construction of complex ritual landscapes. As one of the earliest examples of large-scale monumental stone structure construction in global prehistory, understanding mustatils can enlighten us on human-environment interaction during the Neolithic.

Monitoring of Architectural Monuments

The article presents the main provisions that it is advisable to follow when organizing and conducting monitoring during the operation of cultural heritage sites. It is noted that the existing regulatory documents do not take into account the specifics of monitoring during operation, but are mainly aimed at protecting the monument from neighboring construction.Criteria are proposed to control the technical condition of historical buildings. Among them is the rate of development of long-term precipitation, which is considered as an indicator of the intensity of natural and man-made impacts on the building.Among them is the rate of development of long-term precipitation, which is considered as an indicator of the intensity of natural and man-made impacts on the building. It is noted that for stone structures, critical masonry stretching deformations serve as an effective criterion for the preservation of historical buildings, since in calculating the interaction of structures and foundations they are the primary criterion for calculating the second group of limiting states. In relation to it, the criterion of absolute precipitation and relative difference of precipitation is secondary. It is shown that over time, for buildings built on weak water-saturated clay soils, an increase in the unevenness of precipitation occurs. Special attention is paid to taking into account the accumulated uneven precipitation of buildings of historical development. The article presents the most characteristic types of deformations of buildings, among which in St. Petersburg the bend is most common, which is due to the regularity of building and rebuilding sections of urban neighborhoods.Monitoring is also considered as a reliable means of diagnosing the technical condition of the monument. The monitoring function is considered as a means of controlling the limitations of the monument’s operability, which continues to be operated in conditions of limited operational technical condition.

제주 돌문화 고찰

Jeju stone culture is a representative culture of the Jeju people, reflecting their perception of stones symbolized through their life experiences. In religious legends or geomantic tales, stones possess sacredness or function as objects of taboo and exorcism. In natural legends, stones as megaliths symbolize the tragedies of Jeju people's lives. In human legends, stones emphasize women's chastity and virtue. In folk songs, stones are borrowed or used as metaphors to express thoughts and emotions. As inanimate objects, stones represent solidity and dullness, and the metaphorical emotions are firmly pessimistic. Stone tools take advantage of strong friction, water resistance, and fire safety. In agriculture, the batdam (farmland stone walls) signifies the recognition of ownership and a boundary. As historical relics, stone structures like jatseong for raising livestock highlight the entire island as a national ranch. In folk beliefs, stones are worshiped and prayed to, with examples like dolmireuk (stone Maitreya) or bultap (stone pagoda) being objects of devotion for the desire to bear and raise children and for healing illness.

Developing the composition of fine-grained concrete from the waste of the mining and processing enterprise

The object of this study is fine-grained concrete from the waste of mining and processing plants. These wastes are fine-grained dusty sands of polymineral composition. Their use as an aggregate for concrete is restrained by high water consumption, which does not make it possible to obtain sufficient strength for concrete. Therefore, the problem to be solved was the substantiation of the composition of fine-grained concrete from these wastes with mineral and chemical additives, which would ensure obtaining physical-mechanical and hydrophysical properties reasonable for the production of construction articles. The composition of fine-grained concrete from the waste at the Poltava Mining and Processing Plant and slag Portland cement in a ratio of 3:1 and additives of micro silica (15 % of the cement mass) and polycarboxylate superplasticizer (2 % of the cement mass) with W/C=0.5 was obtained. The compressive strength of this concrete reaches 40 MPa, which exceeds the strength of fine-grained concrete of a similar composition on natural fine-grained sand by 3 times. This is due to a greater degree of cement hydration, a greater number of formed hydration products, the presence of silica and quartz particles, a more uniform alternation of gel, silica particles, and crystal hydrates in the structure of cement stone. As a result, the structure contains a larger number of electro heterogeneous contacts between particles and grains that have negative (quartz, calcium hydro silicates) and positive (crystal hydrates of portlandite, hydro aluminates and calcium hydrosulfoaluminate) surface charges. This is what determines the achieved strength and water resistance of fine-grained concrete. The resulting composition of fine-grained concrete is recommended for the production of construction articles.

Conservation of stone heritage buildings: Exploring the algicidal properties of biologically-synthesized nano-silver

The degradation of stone heritage buildings by pioneer plants such as algae is a major challenge in heritage conservation research worldwide. At present, there is a lack of effective algaecides to inhibit the growth of algae on stone structures, prompting an urgent need to explore effective green methods to remove algae colonizing on surfaces of stone heritage buildings. Therefore, we explored the use of aqueous and alcoholic extracts of four plant leaves (Cinnamomum cassia leaf, Syzygium aromaticum leaf, Thymus mongolicus leaf and Pogostemon cablin leaf) to prepare silver nanoparticles. By optimizing the synthetic parameters, we optimized the yield of the nanoparticles and examined their algicidal activities through in-vitro and in-situ experiments. The experimental results showed that the chlorophyll-a concentrations of algae treated with nano-silver synthesized from the alcoholic extract of Cinnamomum cassia leaf decreased approximately threefold, and the algae removal rate reached 71.34%. Meanwhile, nano-silver treatment made the color of the stone chips colonized with algae close to the color of the uncolonized algae, which demonstrated that the nano-silver can effectively remove the algae colonized on the stone chips. This study confirms that nano-silver synthesized from plant leaves offer a viable strategy as a ‘green’ algaecide for stone heritage buildings.

Scandinavian Erratics in the Cultural Heritage Sites of Western Poland

In north-western Poland, cultural and historical structures were erected using erratic boulders of Scandinavian origin. These structures have yet to be subjected to detailed analysis with the aim of determining their origin, type of erratic boulders and rock abundance of a given petrographic type. This topic has not been addressed by art historians in previous studies of similar structures. The objective of this paper is to present five illustrative examples of stone structures that are closely related to cultural heritage in north-western Poland. A comprehensive inventory of the stone material is presented, categorised according to petrographic types. This is accompanied by a guide to the erratics. Furthermore, this article addresses the principles of geoethics and the concept of sense of place, with the objective of fostering a sense of pride in cultural heritage among residents and viewers. The objective was to identify the current and potential future geosystem services that erratic boulders can provide at the aforementioned locations. The survey methods were non-intrusive and included a comprehensive analysis of the stone material at eye level. Furthermore, in addition to graphic and photographic archiving, the petrographic type of rock and the type of indicative erratics were identified in carefully designed test fields. The results were subjected to basic statistical calculations. The results obtained represent a new corpus of knowledge that can be employed in the sustainable development of the five regions through the utilisation of a tool such as geotourism. It is anticipated that the implementation of innovative initiatives aimed at fostering geoenvironmental awareness and providing educational benefits, such as disseminating knowledge about the petrography and history of the sites (including the evolution of stone workshops and techniques), the role of historic buildings in strengthening attachment to roots, and their promotion in the media and on the internet, will result in the attraction of a more diverse group of tourists with interests beyond the current tourist and recreational offerings.

Study on the Compatibility of Acrylic Acid-acrylamide-diethyldiallyl Ammonium Chloride Copolymer with Cement Slurry in CO2 Environment.

This paper investigates the structure and aggregation stability of acrylic acid-acrylamide-diethyldiallylammonium chloride (FA367), followed by an investigation into the impact of acidic CO2 environments on the interaction between FA367 and cement slurry. The results showed that FA367 formed stable flocculation in cement slurry filtrate, which was not affected by acid gas CO2. With an FA367 concentration of 0.6%, the fluidity of the cement slurry measures 18.1 cm, but this fluidity is lost upon introducing CO2. At 90 °C, the compressive strength after 1, 3, and 7 days is 10.23, 77.48, and 62.97%, respectively, compared to pure cement. However, with the addition of CO2, the compressive strength increases to 27.03, 99.59, and 75.47%, respectively. The interaction between FA367 and cement slurry impedes cement hydration without altering hydration product composition. Instead, it fosters needle-like aggregations between hydration products, affecting the cement stone's compact structure. Upon CO2 introduction, these needle-like structures diminish, resulting in an overall more intact cement stone structure.

Weathering Tests on Raw and Consolidated Vicenza Stone.

The preservation of cultural heritage, particularly historical stone structures, represents a very challenging matter due to several environmental and anthropogenic factors. Vicenza stone, a calcareous rock known for its historical significance and widespread use in architectural masterpieces, requires significant attention for conservation. In fact, as the demand for sustainable and effective preservation methods intensifies, the exploration of innovative consolidation strategies becomes essential. To this end, inorganic consolidants, based on alkaline silicate formulations and nano-silica, were explored for their promising performance in enhancing the surface properties and chemical stability of Vicenza stone. In particular, the durability of treated and untreated Vicenza stone samples was evaluated by means of accelerated weathering tests such as freeze-thaw cycles, salt crystallization and simulation of acid rain. The experimental results revealed that Vicenza stone is very resistant to the effects of freeze-thaw cycles and acid rain; both the accelerated weathering tests did not show significant differences between treated and untreated VS samples. A different behavior was detected for the test for resistance to salt crystallization, whose findings led us to deduce that, for this kind of degradation, it is possible to observe a more beneficial effect of the consolidation treatments on the stone durability.

Electrical resistivity tomography of a masonry bridge: assessing water infiltration on Prebends Bridge, Durham, UK

ABSTRACT Non-invasive imaging methods are a useful tool in informing conservation actions for historical buildings. Electrical Resistivity Tomography (ERT) is widely used in geophysics to image the subsurface but has been seldom used for non-invasive imaging of small-scale masonry structures. Here, we propose an adaptation of the method allowing non-damaging investigation of larger-scale stone structures. We report results of an ERT survey of Prebends Bridge in Durham, a heritage masonry structure constructed in 1778. Our assessment is based on data acquired on the paved top surface of the bridge, which is subsequently modelled and inverted with the use of open-source software. Final images of the internal structure of the bridge reveal areas of lower electrical resistivity, that we interpret as representing regions of water saturation. Locations of low resistivity areas are in good agreement with the structural defects and patches of seepage observed externally. These results will help inform remediation work, to preserve this historical structure from further water damage. In future studies, time-lapse imaging may help to highlight water pathways unambiguously (through comparison of dry/wet periods), while additional electrode arrays installed on the sides/base of the structure could be used to better constrain 3D internal structure.

X-Ray powder diffraction - structure prediction of unknown stone using foolproof and GSAS - Rietveld Refinement

A slightly violetish blue, cone shaped, hexagonally soft sheen, a soft lustre on a surface, and semi/nearly transparent with reasonable weight of a natural stone has been analysed as a part of investigation for determining the components of the stone thereby leading to identify as to whether the stone is in a category of gemstone, radioactive elements, or otherwise. Philips, X-pert Pro, DY993 X-ray Powder Diffractometer has been employed for collecting the powder diffraction data in the Bragg-Brentano geometry using proportional counter in the 5° < 2θ < 85° range at room temperature 300 K. The data, thus, obtained from the XRPD has been used in FullProf and GSAS (General Structure Analysis Software) software with the Rietveld refinement technique for elucidating the possible molecular structure of the unknown stone. In addition to the XRPD technique, the physical and optical parameters such as specific gravity, hardness, luster, transparency, cleavage, streak and other associated minerals have also been measured. This study reveals that the stone is in a category of precious stone which is of mineral deposition Corundum, a blue sapphire. The structure has been determined from Rietveld analysis in space group R-3c, with a= 4.7655 (2) Å and c = 13.0132(3) Å.

Новые памятники археологии на северном побережье Кандалакшского залива Белого моря

The article is devoted to the results of the archaeological expedition of the Kola Scientific Center of the Russian Academy of Sciences on the northern shore of the Kandalaksha Bay of the White Sea near the city of Kandalaksha and on the Kolvitsa River in 2023. Three new archaeological monuments have been recorded: Niva XXIII — boulder pit, Kandalaksha XVI – charcoal pits and Kolvitsa – stone structures. The boulder pit is located on an ancient sea terrace, on the western slope of Mount Volosyanaya, 1 km from the Niva River. Three charcoal pits are located on the northern shore of Malaya Pitkulya Bay, near the southern slope of Mount Krestovaya, not far from the labyrinth. This is the first discovery of such objects in Russian Lapland and they date back to the late 15th–16th centuries. Seven formations of boulders are located on the northern bank of the Kolvitsa River near the rapids. Analogs are known to them in other places of Russian Lapland. There are also boulder pits on the Khlebnaya River and on the coast of the Barents Sea. The dating and ethnicity of the boulder structures are still speculative.

In vitro Biomineralization Ability of Magnesium-Doped Coral Hydroxyapatite Coating Prepared by Pulsed Laser Deposition

Coral hydroxyapatite (CHA) is a calcium phosphate that has a similar inorganic composition to human bone and the porous structure of coral stone. Due to its interconnected network like pore structure, it can serve as a framework for bone conduction. In this study, CHA films and Mg-CHA films were deposited on titanium and silicon substrates by Pulsed laser deposition, and then the films were heat treated respectively. Studies on the adhesion of the coating showed that the heat-treated Mg-CHA film adhered better to the titanium substrate. The experimental study on biomineralization in vitro showed that a small amount of porous structure appeared in the heat-treated Mg-CHA after immersion in SBF for three days, and the porous structure was visible after immersion for seven days. After 14 days, a new apatite layer formed on the surface. This suggested that magnesium undergoes chemical corrosion in SBF, leading to rapid ion exchange, which results in the formation of porous structures and promotes the development of an apatite-like layer. In summary, the heat-treated Mg-CHA films had superior biomineralization properties.

A Romano-British Settlement at Hawbank Field, Skipton

An excavation in early 2021 investigated the remains of Romano-British settlement at Hawbank Field, on the north-eastern edge of Skipton. Activity had begun at least by the second century AD and extended into the late fourth or early fifth centuries, concentrated around a series of ditched and banked enclosures. Stone structures and surfaces and numerous ditches and pits were associated with the Romano-British settlement. Two inhumations were radiocarbon dated to the third-fourth century AD. Fragmentary remains, found alongside the Romano-British features, suggest some activity in the medieval period as the rest of the site was incorporated into an open field system.

Strength Indicators of Fiber Reinforced Concrete with Carbon Nanomaterials

Concrete composites with low defects, dense and homogeneous, with a high degree of adhesion between the cement matrix and aggregates, as well as a high ratio between static tensile and compressive strengths and plasticity have the best crack resistance characteristics. This ratio increases in the case of the use of fiber-reinforced concrete. Modern research in nanotechnology focuses on the management of matter at the nanoscale level, which makes it possible to create materials with new properties. Due to the high aspect ratio, flexibility, high strength and rigidity, carbon nanotubes (CNTs) exhibit reinforcing properties. Due to their nanoscale features, CNTs interact with a complex network of calcium-silicate-hydrate binder (C – S – H), contribute to a decrease in porosity and compaction of the cement stone structure, increase the shear forces of matrix adhesion in the contact zone. Thus, there are all prerequisites to assert that fiber concrete with a cement matrix modified with carbon nanotubes will have the required high strength characteristics and crack resistance due to multilevel dispersed reinforcement and the efficient operation of fiber in a nanomodified concrete matrix. This article presents the results of testing samples made of cement stone, concrete and fiber concrete with carbon nanotubes. The presence of carbon nanotubes in cement stone contributes to an increase in compressive strength by 11 %, tensile strength during bending by 20 %. The test results of samples made of reinforced fiber concrete modified with nanocarbon materials have shown an increase in tensile strength during bending up to 109 %, tensile strength during splitting up to 82 %, axial tensile strength up to 78 %.

ВЛИЯНИЕ ПЛАСТИФИКАТОРА НА ПРОЦЕССЫ ПЕРЕКРИСТАЛЛИЗАЦИИ ПРИ ТВЕРДЕНИИ ДВЕНАДЦАТИКАЛЬЦИЕВОГО СЕМИАЛЮМИНАТА КАЛЬЦИЯ

The mechanism of structure formation during hydration of duodecalcium semialuminate in the presence of plasticizer is considered. The purpose of the study was to determine the influence of polycarboxylate-based plasticizer on the formation and morphology of the hydrate phases formed. The object of the study was the mineral duodecalcium semialuminate 12CaO-7Al2O3 of stable α-form, having cubic syngony and plasticizer on polycarboxylate basis. The structure of cement stone was studied using X-ray phase and electron microscopic analysis. The mechanism of structure formation during hydration of duodecalcium semialuminate 12CaO∙7Al2O3 in the presence of plasticizer is presented, which consists in the formation of finely dispersed poorly crystallized hexagonal crystals of calcium hydroaluminate. The presence of superplasticizer in the composition of hydrated calcium aluminate slows down the nucleation and growth of crystalline hydrates due to the film formed on the surface of the interface between liquid and solid phases, creating a structural and mechanical barrier, which leads to slower saturation of the liquid phase, but promotes the formation of a greater number of crystallization centers and simultaneous growth of small crystals of both hexagonal and cubic habitus.

Evaluation of the influence of an aggressive environment on the durability of the cement stone

The paper proposes methods for assessing the durability of building materials and structures based on Portland cement when exposed to aggressive environments that mimic the products of the vital activity of bacteria on building materials. To determine the main parameters of the model of degradation of building materials under the action of aggressive environments, a mathematical model has been developed in the form of integral and differential relations connecting these parameters. A technique for identifying the mechanical characteristics included in these models based on the solution of inverse biodegradation problems has been developed. The analysis of changes in the structure of the cement stone was carried out using the results of computed tomography, and the regularities of the distribution of pores in the cement stone from the time of exposure were obtained. Based on experimental and numerical studies, it has been established that the mechanism of destruction of cement stone obtained by the traditional method and activation in the vortex layer apparatus is different. The difference lies in the greater accumulation of cement stone interaction products in the activated sample, which is confirmed by a shift in porosity to less than 0.5 mm and a lower solubility value compared to the control composition. The compressive strength of the samples as a result of exposure for 28 days decreased by 37% and 20% for the control and activated compositions. The mass of the studied samples as a result of exposure decreased by 49% and 21%, respectively. On the basis of this mechanism, a mathematical model of the process of material degradation in an aggressive one is developed, taking into account changes in porosity and acidity concentration, and dependence of material strength reduction are obtained.

ПЕРСПЕКТИВЫ ИСПОЛЬЗОВАНИЯ ОТХОДОВ СТРОИТЕЛЬНОЙ КЕРАМИКИ ПРИ ПРОИЗВОДСТВЕ СТРОИТЕЛЬНЫХ МАТЕРИАЛОВ

The main technological aspects of the production of building ceramics are given. Based on the analysis of literary sources, a comprehensive assessment of the feasibility of using construction ceramic waste as a secondary raw material for the production of new building materials was carried out. Based on the research of modern scientists, it has been established that the waste from the scrap of building ceramics is suitable for use as an aggregate, partial replacement of cement and a reactive additive in concretes and mortars. When using scrap of con-struction ceramics as an aggregate, it is recommended to limit the substitution of natural aggregate at the level of 20-30%, together using various additives: plasticizing and improving rheotechnological and physico-mechanical properties of concrete. Finely ground waste from brick scrap has pozzolan activity and, when used as a reactive additive or partial replacement of cement in concretes and mortars, up to 20-25% can improve the structure of cement stone, increase strength, reduce macroporosity and penetration of chloride ions, and increase sul-fate resistance. This kind of binder is prone to a later set of strength compared to Portland cement. In addition, the waste of building ceramics can be used in the production of alkali-activated cements and slag-alkali binders, as well as s raw materials for the production of new bricks or the construction of road surface bases. It has been revealed that the production of building materials and products based on con-struction ceramics waste is a promising direction for the development of construction production. It is possible not only to obtain materials of equal quality to products based on natural raw materials, but also with improved characteristics.