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1
ERGİN, Şefika, Berfin GÖKDEMİR, Seyhan YARDIMLI, and Murat DAL. "DETERIORATION ON THE STONE SURFACES OF THE DIYARBAKIR NEBI MOSQUE." INTERNATIONAL REFEREED JOURNAL OF DESIGN AND ARCHITECTURE, no. 27 (2022): 1–32. http://dx.doi.org/10.17365/tmd.2022.turkey.27.01.
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Aim: The study aims to determine the types of deterioration that occur in natural stones of the Nebi Mosque, and the effects that cause them to deteriorate, and to draw attention to the importance of protecting the building. The scope of the study is constituted by the findings obtained by observation-based research in light of the current literature. Method: In the study, the deteriorations observed in the basalt stone and limestone of the Diyarbakır Nebi Mosque were examined by photographing in-situ. In addition to the photographs, the types of deterioration on the facades were processed using the mapping method and the areas of the stone surfaces affected by the deterioration types were calculated. The obtained numerical data were used to compare the degradation types quantitatively. Findings: In the stone materials of the building, physicomechanical deterioration such as crack formation, alveolization, and abrasion, which are frequently observed in hot-dry climates, were found. In addition to physicomechanical deterioration, chemical deterioration types such as corrosion, black crust formation, efflorescence/salt crystallization, and microkarst formation and deterioration caused by biological effects were observed. Deterioration caused by faulty repairs examined in the category of anthropogenic deterioration also constitutes the damage observed in the building. In addition to the deterioration detected in the study, it is among the findings to reveal the factors that cause deterioration, such as humidity, wind, air pollution, and faulty repair. Results: Diyarbakır Nebi Mosque, which is a historical and cultural heritage, is damaged by natural stone deterioration due to environmental factors. In the study, the technical properties of basalt and limestone forming the structure were determined and the types of deterioration were included. Attention was drawn to the structure and awareness was tried to be created about taking the necessary measures.
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Kim, Yun Hae, Jun Mu Park, Jin Woo Lee, Jae Hyun Jeong, and Kyung Man Moon. "Moisture Deterioration Mechanism of Fiber Reinforced Composites." Advanced Materials Research 750-752 (August 2013): 176–85. http://dx.doi.org/10.4028/www.scientific.net/amr.750-752.176.
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Generally, the moisture absorbed in the composites plasticizes the resin. And it makes the composites expansion in volume and generates the cracking at the same time, So, the fracture is often generated in the composites by those reason. Therefore, in this study, the change of mechanical properties due to the moisture-absorption for the carbon fiber reinforced composites in comparison with basalt fiber and glass fiber reinforced composites are investigated. The specimens for the carbon, basalt, and glass fiber reinforced composites manufactured with the ASTM standard. The specimens immersed in distilled water at 80°C during 100 days and the coefficient of moisture was measured in according to the Fick's law. In addition, after drying process, the humidity-absorbed specimen under 80°C for 1 day, the recovery rate was measured. As a result, the coefficient of moisture-absorption of carbon fiber reinforced composite material was the lowest at approximately 3 % because the interface coherence with the fiber and resin are the most strong. Also, after drying process, the recovery rate was 20 percent higher than the others.
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Liu, Hua Wu, Kai Fang Xie, Wei Wei Hu, Han Sun, Shu Wei Yang, and Tian Yang Yang. "Water Absorption of Basalt Fiber Reinforced Fir Sawdust Panel." Advanced Materials Research 821-822 (September 2013): 1171–74. http://dx.doi.org/10.4028/www.scientific.net/amr.821-822.1171.
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Moisture absorption results in dimensional deformation, mechanical property deterioration and fungi attack in wood composite products, which may be improved by the reinforcement of waterproof material. In this study, we used basalt fibre as a reinforcement material for fir sawdust panels and investigated the influence of basalt fibre content and length on moisture absorption rate and thickness swelling. The reinforced fir sawdust panel groups largely reduced water absorption rate, and the smallest thickness swelling occurred when the content of basalt fibre was 5%. The results also indicated that the basalt fibre content played a more important role than basalt fibre length on the thickness swelling of the reinforced fir sawdust panels.
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Ye, Zhenni, Xiaoli Liu, Huan Sun, Qinxi Dong, Weisheng Du, and Qijian Long. "Variations in Permeability and Mechanical Properties of Basaltic Rocks Induced by Carbon Mineralization." Sustainability 14, no. 22 (November 16, 2022): 15195. http://dx.doi.org/10.3390/su142215195.
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Carbon capture, utilization, and storage (CCUS/CCS) is a strategic choice for ensuring energy security and reducing carbon dioxide emissions across the globe. The injection of CO2 into the basaltic reservoir is one strategy for the permanent disposal of carbon emissions. Basaltic rocks, which are widely distributed in Hainan Island, are capable of CO2 geological sequestration. In this study, the reaction of CO2-NaOH/Ca(OH)2-basaltic rocks under conditions of 6.0 M Pa and 30 °C was performed using basaltic samples collected from the Fushan area of the Hainan Province to evaluate the sequestration of CO2 in basalt by mineralization. Then, the effect of CO2 mineralization on the permeability and mechanical properties of basaltic rocks was evaluated using X-ray computer tomography and triaxial compression testing at 21.0 MPa. In addition, microwave technology was used to irradiate the basaltic rocks before mineralization. Changes in the permeability of basalt before and after mineralization and microwave irradiation were simulated numerically, and their effects on the mechanical strength deterioration of basalt were analyzed according to the rock mechanics using triaxial testing. Based on these results, a new method for the induction of basalt deterioration, mineralization, CO2 injectivity, and storage capacity using microwave irradiation is proposed for use in CCUS/CCS engineering.
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Dobiszewska, Magdalena, Waldemar Pichór, and Paulina Szołdra. "Effect of basalt powder addition on properties of mortar." MATEC Web of Conferences 262 (2019): 06002. http://dx.doi.org/10.1051/matecconf/201926206002.
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The study evaluates the use of waste basalt powder as a replacement of cement to enhance hydration of cement and mortar properties. The basalt powder is a waste resulting from preparation of aggregate used in asphalt mixture production. Previous studies have shown that analysed waste used as a fine aggregate replacement has a beneficial effect on some properties of mortar and concrete, i.e. compressive strength, flexural strength and freeze resistance. The present study shows the results of the research concerning the modification of cement paste and mortar with basalt powder. The modification consists in adding the powder waste as a partial replacement of cement. The percentages of basalt powder in this research are 0-40% and 0-20% by mass of cement in the pastes and mortars respectively. The experiments were carried out to determine the influence of basalt powder on cement hydration, as well as compressive and flexural strength. Results indicate that addition of basalt powder as a replacement of cement leads to deterioration of compressive strength. The flexural strength of mortar is improved in some cases. Waste basalt powder only slightly influences the cement hydration.
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Liu, Hua Wu, Kai Fang Xie, Wei Wei Hu, Han Sun, Shu Wei Yang, and Tian Yang Yang. "Water Absorption of Wood Composite Modified by Basalt Glass Powder." Advanced Materials Research 821-822 (September 2013): 1168–70. http://dx.doi.org/10.4028/www.scientific.net/amr.821-822.1168.
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Moisture sorption of wood sawdust panel results in dimensional variation, deterioration of mechanical property and fungi attack, which may be improved by the reinforcement of waterproof material. In this study, the fir sawdust panel was reinforced by basalt glass particles with size smaller than 5 micron, in order to reduce moisture penetration. When the content of basalt glass powder was 15%, both the thickness swelling and 24 h water absorption rate of wood composites reached their minimum values, which were 2.7% and 11%, respectively. The thickness swelling was far smaller than the 45% upper limit of medium density fiberboard as described by standards GB/T17657-1999.
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Lohmus, Rynno, Heikko Kallakas, Eero Tuhkanen, Volodymyr Gulik, Madis Kiisk, Kristjan Saal, and Targo Kalamees. "The Effect of Prestressing and Temperature on Tensile Strength of Basalt Fiber-Reinforced Plywood." Materials 14, no. 16 (August 20, 2021): 4701. http://dx.doi.org/10.3390/ma14164701.
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The reinforcement of plywood is demonstrated by laminating pretensioned basalt fibers between veneer sheets, to fabricate so-called prestressed plywood. Belt type basalt fibers bearing a specific adhesion promoting silane sizing were aligned between veneer sheets with 20 mm spacing and were pretensioned at 150 N. Three-layer plywood samples were prepared and tested for tensile strength at room temperature and at 150 °C. The room temperature tensile tests revealed a 35% increase in tensile strength for prestressed plywood compared to that of the conventional specimen. The reinforcement effect deteriorated at 150 °C but was restored upon cooling to room temperature. The deterioration is attributed to the weakening of bonding between the basalt fibers and phenolic resin matrix at elevated temperatures due to the softening of the resin.
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Wu, Zhengguang, Chen Zhang, Peng Xiao, Bo Li, and Aihong Kang. "Performance Characterization of Hot Mix Asphalt with High RAP Content and Basalt Fiber." Materials 13, no. 14 (July 15, 2020): 3145. http://dx.doi.org/10.3390/ma13143145.
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Incorporating reclaimed asphalt pavement (RAP) into asphalt mixtures achieves astonishingly environmental and economic benefits. However, there is hesitation to use higher RAP content due to the concern regarding the deterioration in pavement performance, especially the cracking resistance. Basalt fiber has been considered an effective additive to reinforce the performance of asphalt mixtures and, subsequently, the reinforcement effect is also expected for high-RAP content mixtures. Therefore, this study investigated the effect of basalt fiber on the pavement performance of asphalt mixtures with 0%, 30%, 40%, and 50% RAP contents against high-temperature performance, moisture susceptibility, low-temperature and intermediate-temperature cracking resistance, based on the wheel-tracking test, the uniaxial penetration test, the freeze-thaw splitting test, the low-temperature bending beam test, the semicircular bend fracture test and the indirect tensile asphalt cracking test, respectively. In addition, a performance-space diagram was developed to determine the mixture performance shift caused by basalt fiber. The results showed that adding basalt fiber compensated for the detrimental effect caused by RAP, leading to significant enhancement in moisture susceptibility and low- and intermediate-temperature cracking resistance of mixtures with high RAP content, along with the enhancement in high-temperature performance, indicating that basalt fiber can contribute to the use of high RAP content.
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EDET, Abu S., Hidenori TAKAHASHI, and Taro SEKI. "Ecological Role of Micro-Organisms on Surface Deterioration of Cross River Basalt Monoliths in Nigeria." Tropics 9, no. 2 (2000): 117–32. http://dx.doi.org/10.3759/tropics.9.117.
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Yu, Jianqiao, Hongxia Qiao, Feifei Zhu, and Xinke Wang. "Research on Damage and Deterioration of Fiber Concrete under Acid Rain Environment Based on GM(1,1)-Markov." Materials 14, no. 21 (October 23, 2021): 6326. http://dx.doi.org/10.3390/ma14216326.
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With steel fiber and basalt fiber volume dosing serving as variation parameters, a total of 200 d cycles of acid rain corrosion cycle tests were conducted on fiber concrete in this study. We selected three durability evaluation parameters to assess the degree of damage deterioration on fiber concrete, used scanning electron microscopy, mercury intrusion porosimetry, and a dimensional microhardness meter to analyze the concrete micromorphology, and established a GM(1,1)-Markov model for life prediction of its durability. Results reveal that the acid rain environment is the most sensitive to the influence of the relative dynamic elastic modulus evaluation parameter, and concrete has specimens that show failure damage under this parameter evaluation. Incorporation of fibers can reduce the amount of corrosion products inside the concrete, decrease the proportion of harmful pores, optimize the mean pore-size, and significantly improve the resistance to acid rain attack. Concrete with 2% steel fiber and 0.1% basalt fiber by volume has the least change in durability damage, and the predicted service life by GM(1,1)-Markov model is 322 d.
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Schoene, Blair, Michael P. Eddy, Kyle M. Samperton, C. Brenhin Keller, Gerta Keller, Thierry Adatte, and Syed F. R. Khadri. "U-Pb constraints on pulsed eruption of the Deccan Traps across the end-Cretaceous mass extinction." Science 363, no. 6429 (February 21, 2019): 862–66. http://dx.doi.org/10.1126/science.aau2422.
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Temporal correlation between some continental flood basalt eruptions and mass extinctions has been proposed to indicate causality, with eruptive volatile release driving environmental degradation and extinction. We tested this model for the Deccan Traps flood basalt province, which, along with the Chicxulub bolide impact, is implicated in the Cretaceous-Paleogene (K-Pg) extinction approximately 66 million years ago. We estimated Deccan eruption rates with uranium-lead (U-Pb) zircon geochronology and resolved four high-volume eruptive periods. According to this model, maximum eruption rates occurred before and after the K-Pg extinction, with one such pulse initiating tens of thousands of years prior to both the bolide impact and extinction. These findings support extinction models that incorporate both catastrophic events as drivers of environmental deterioration associated with the K-Pg extinction and its aftermath.
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Guo, Xiangke, Zuquan Jin, Chuansheng Xiong, Tao Sun, Ning Li, Yong Yu, and Xiaoying Zhang. "Deterioration of mechanical properties of basalt/carbon hybrid FRP bars in SWSC under seawater corrosive environment." Construction and Building Materials 317 (January 2022): 125979. http://dx.doi.org/10.1016/j.conbuildmat.2021.125979.
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Wu, Duo. "Study on Damage Characteristics of Fiber Concrete under Acid Rain Erosion." E3S Web of Conferences 198 (2020): 01010. http://dx.doi.org/10.1051/e3sconf/202019801010.
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Concrete structure will be corroded under acid rain scouring and soaking for a long time, which has a great influence on its durability life. In order to further study the damage characteristics of fiber reinforced concrete under acid rain erosion, the formation mechanism of acid rain and its influence on the corrosion and deterioration of concrete and fiber materials were analyzed in this paper. Taking basalt fiber concrete as an example, the characteristics such as porosity, compressive strength and mechanical indexes were studied and analyzed. Moreover, the reasons for the optimal fiber content was briefly analyzed. The results show that the inner structure of basalt concrete mixed with 0.1% fiber was the most stable and the corrosion resistance was the most satisfying.This conclusion has certain reference significance for the corrosion damage research of fiber reinforced concrete.
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Tomina, A. M., A. Yerоmenko, and V. Makarov. "Influence of basalt fiber on tribological properties of secondary polyethylene terephthalate." Problems of tribology 100, no. 2 (June 23, 2021): 58–64. http://dx.doi.org/10.31891/2079-1372-2021-100-2-58-64.
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The article considers the influence of discrete (3 mm) basalt fiber on the tribological properties of secondary agglomerated polyethylene terephthalate. It was found that the introduction of the filler reduces the coefficient of friction and the intensity of linear wear of the initial polymer 1,5 and 4,5 times, respectively, reaching the minimum values at a basalt fiber content of 5 mass.%. The obtained results are due to the fact that the appearance of basalt fiber strengthens the polymer matrix that confirms the increase in hardness by 15%, and inhibits the development of cracks on the surface of the composite. The study of the temperature in the contact zone showed its increase that is due to the low thermal conductivity of the filler (0,064 - 0,096); as a result, there is an accumulation of heat in the friction zone. Further increase in fiber content (up to 10 mass.%) leads to a sharp deterioration of the tribological and physico-mechanical properties of basaltoplastics because of the increase in the defect of the material. It is determined that the effective content of filler in the polymer matrix is 5 mass.%. As a result, this composite was recommended for the manufacture of parts for movable joints of agricultural, automotive and metallurgical equipment.
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Getahune, M. Bitewlgn, Qian Gu, Bo Li, and Cheng Fang Sun. "Experimental Study on Earthquake-Damaged RC Frame Columns Repaired with Sprayed Basalt FRP." Advanced Materials Research 889-890 (February 2014): 1438–44. http://dx.doi.org/10.4028/www.scientific.net/amr.889-890.1438.
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Repairing of past earthquake-damaged members that are highly susceptible to future attack is necessary to prevent civil infrastructure destruction and consequent lives lose.Sprayed basalt FRP composite was tested and presented here as a promising solution.In this study, three 1/2 scaled reinforced concrete frame columns were used to investigate the effectiveness and feasibility.One column was damaged to failure and used as a reference specimen.The other two columns were damaged up to the yielding of main bars simulating deterioration of the structure due to seismic action to a control level.These two columns were repaired with sprayed basalt fiber reinforced polymer (BFPR) composite.Different thicknesses of sprayed BFRP composite were applied.Each specimen was subjected to lateral low-frequency cyclic loading and simultaneous constant axial load to simulate seismic action and dead load respectively.The test result analysis showed that sprayed BFRP can increase the load carrying capacity, enhance the energy absorption capacity, and can effectively restore the strength of past earthquakedamaged RC column.
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Giovannacci, David, Jean-Didier Mertz, Blen Taye Gemeda, Antoine Garric, and Romain Mensan. "Non-Destructive Analysis to Investigate the Stone Alterations at a UNESCO World Heritage Site." Journal of Human, Earth, and Future 3, no. 2 (June 1, 2022): 147–58. http://dx.doi.org/10.28991/hef-2022-03-02-01.
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This study concerns the eleven monolithic churches in Lalibela, in northeastern Ethiopia, a UNESCO World Heritage Site and currently the main pilgrimage site in Ethiopia. In 2019, on the initiative of Prime Minister, the French authorities proposed their support in the management on the site of the churches. To do so, the French Development Agency (AFD), in collaboration with the Ministry of Europe and Foreign Affairs and with the support of the Ministry of Culture, granted a feasibility study to examine ways of restoring, conserving, and developing the rock-hewn churches. The objective of the feasibility study conducted was to produce the preliminary technical diagnostics required for the preparation of the comprehensive project to restore, conserve, and develop the site. In order to propose a protection and conservation solution, diagnostics and analysis of the pathology of the rocks were made during two campaigns in November 2019 and November 2020. The rock pathology teams implemented non-destructive and minimally invasive analysis. The complementary methods acquire data from the rock surface and the different forms of differential alteration of the scoriaceous basalt. The objective is to characterize, through comparative analyses, the impact of a protective shelter on the alteration kinetics of the rock. The analysis, coupled with on-site observations, suggests that deterioration linked to liquid water and the persistence of a state of high water content is more damaging than the deterioration risk linked to salt crystallization. As water is the key factor in the very harmful alteration for the conservation of scoriaceous basalt as a heritage material in humid natural environments, it seems useful to fully cover the churches. Doi: 10.28991/HEF-2022-03-02-01 Full Text: PDF
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Khedr, Mohammed S. A., Mona F. Ali, Abdullah M. A. Kamel, and Manal A. A. El-Ghanam. "Archaeometric study of the historic terrazzo pavement of Prince Mohamed Ali Museum, Cairo, Egypt." Pollack Periodica 15, no. 1 (April 2020): 221–32. http://dx.doi.org/10.1556/606.2020.15.1.21.
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Abstract This research will shed light on studying a terrazzo pavement in Prince Mohamed Ali Museum (the case study). The authors used visual inspection, stereo microscope, USB microscope, XRPD analysis, and SEM.EDX to identify its components, deterioration aspects and execution techniques. The XRPD and SEM.EDX results revealed that Portland cement was used in the three layers of terrazzo because of the detection of Hatrurite, Alite, Anorthite, Albite, Aragonite, etc. Many pigments were used in the topping terrazzo layer as; Goethite, Greenalite, Hematite, Azurite and Magnetite. The divider strips were made of brass alloy and the topping layer chips were prepared from basalt, marble and sea shells.
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代, 明江. "Deterioration Mechanism of Steel Fiber-Basalt Fiber Recycled Concrete under the Coupling Action of Freeze-Thaw and Salt Erosion." Material Sciences 12, no. 07 (2022): 666–77. http://dx.doi.org/10.12677/ms.2022.127073.
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Valovoi, Alexander, Peter Koval, Alexander Eremenko, Maksim Valovoi, and Sergei Volkov. "Durability of beams with hybrid reinforcement from metal and basalt fiber reinforced polymer (BFRP) armature." MATEC Web of Conferences 230 (2018): 02035. http://dx.doi.org/10.1051/matecconf/201823002035.
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The article presents the program and the results of experimental tests of beam samples with metal, basalt fiber reinforced polymer (BFRP) and hybrid (metal and BFRP) reinforcement. The samples were made of standard concrete with quartz sand as the fine aggregate and concrete with fine fraction wastes of a mining and beneficiation complex (MBC) used instead of the sand. Short-run tests of the beams under monotonous static loading until destruction enabled the conclusion that durability of the BFRP reinforced beams increased by 37-44% as compared to the metal reinforced beams. When hybrid reinforcing, reduction of the (BFRP) content did not produce an effect on decrease of durability indices; durability gains compared to the beams reinforced by metal made 38-41%. In the BFRP reinforced beams, due to the absence of plastic deformations in this reinforcement, there were no residual deformations after cessation of loading despite significant damage and deterioration of the concrete. Samples of beams made of concrete on fine fraction wastes of MBC, showed 1-8% higher strengths in comparison with similar beams made of concrete with quartz sand as the fine aggregate.
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Wei, Jun, Zhenshan Wang, Weidong Sun, and Runan Yang. "Durability Performance and Corrosion Mechanism of New Basalt Fiber Concrete under Organic Water Environment." Materials 16, no. 1 (January 3, 2023): 452. http://dx.doi.org/10.3390/ma16010452.
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Under corrosive environments, concrete material properties can deteriorate significantly, which can seriously affect structural safety. Therefore, it has important engineering applications to improve the durability performance at a lower economic cost. This paper proposes a new, highly durable concrete using inexpensive construction materials such as basalt fiber, sodium methyl silicate, and inorganic aluminum salt waterproofing agent. With the massive application of sewage treatment projects, the problem of concrete durability degradation is becoming more and more serious. In this paper, five types of concrete are developed for the sewage environment, and the apparent morphology and fine structure of the specimens after corrosion in sewage were analyzed. The density, water absorption, and compressive strength were measured to investigate the deterioration pattern of concrete properties. It was found that ordinary concrete was subject to significant corrosion, generating large deposits of algae on the surface and accompanied by sanding. The new concrete showed superior corrosion resistance compared to conventional concrete. Among other factors, the inorganic aluminum salt waterproofing agent effect was the most prominent. The study found that the strength of ordinary concrete decreased by about 15% in the test environment, while the new concrete had a slight increase. Comprehensive evaluation showed that the combination of basalt fiber and inorganic aluminum salt waterproofing agent had the best effect. Its use is recommended.
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Dong, Shicheng, and Lida Qin. "Study on Evolution Law of Pore Structure and Frost Resistance of High-Performance Activated Cement-Based Composites in Severe Cold Area." Journal of Physics: Conference Series 2348, no. 1 (October 1, 2022): 012017. http://dx.doi.org/10.1088/1742-6596/2348/1/012017.
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In order to explore the frost resistance of high-performance activated cement-based composites(HACC), The freeze-thaw cycle test of HACC with different water-binder ratio and basalt fiber content was carried out, the mass loss rate, relative dynamic elastic modulus and related pore structure parameters of different freeze-thaw cycles were measured, and the influence of different factors on the frost resistance of HACC was studied, and the variation law of pore structure parameters with freeze-thaw cycles was explored. The results show that the mass loss rate of high performance cement-based composites has a small range, the maximum is less than 1% during failure, and the relative dynamic modulus changes significantly, which is the main indicator to evaluate the freeze-thaw failure of HACC; The frost resistance of HACC decreased gradually with the increase of the water-binder ratio, and showed a change rule of first increasing and then decreasing with the increase of basalt fiber content; HACC have good frost resistance when the air content is 3% ~ 4%. The bubble chord length is directly related to the freeze-thaw deterioration characteristics of HACC, and the bubble chord length reflects the frost resistance of HACC to some extent.
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Ondrášik, Martin, and Miloslav Kopecký. "Rock Pore Structure as Main Reason of Rock Deterioration." Studia Geotechnica et Mechanica 36, no. 1 (March 1, 2014): 79–88. http://dx.doi.org/10.2478/sgem-2014-0010.
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Abstract Crashed or dimensional rocks have been used as natural construction material, decoration stone or as material for artistic sculptures. Especially old historical towns not only in Slovakia have had experiences with use of stones for construction purposes for centuries. The whole buildings were made from dimensional stone, like sandstone, limestone or rhyolite. Pavements were made especially from basalt, andesite, rhyolite or granite. Also the most common modern construction material - concrete includes large amounts of crashed rock, especially limestone, dolostone and andesite. However, rock as any other material if exposed to exogenous processes starts to deteriorate. Especially mechanical weathering can be very intensive if rock with unsuitable rock properties is used. For long it had been believed that repeated freezing and thawing in relation to high absorption is the main reason of the rock deterioration. In Slovakia for many years the high water absorption was set as exclusion criterion for use of rocks and stones in building industry. Only after 1989 the absorption was accepted as merely informational rock property and not exclusion. The reason of the change was not the understanding of the relationship between the porosity and rock deterioration, but more or less good experiences with some high porous rocks used in constructions exposed to severe weather conditions and proving a lack of relationship between rock freeze-thaw resistivity and water absorption. Results of the recent worldwide research suggest that understanding a resistivity of rocks against deterioration is hidden not in the absorption but in the structure of rock pores in relation to thermodynamic properties of pore water and tensile strength of rocks and rock minerals. Also this article presents some results of research on rock deterioration and pore structure performed on 88 rock samples. The results divide the rocks tested into two groups - group N in which the pore water does not freeze even when the temperature decreases to -20 ºC, and the second group F in which the pore water freezes. It has been found that the rocks from group N contain critical portion of adsorbed water in pores which prevents freezing of the pore water. The presence of adsorbed water enables thermodynamic processes related to osmosis which are dominantly responsible for deterioration of rocks from group N. A high correlation (R = 0.81) between content of adsorbed water and freeze-thaw loss was proved and can be used as durability estimator of rocks from group N. The rock deterioration of group F is caused not only by osmosis, but also by some other processes and influences, such as hydraulic pressure, permeability, grain size, rock and mineral tensile strength, degree of saturation, etc., and the deterioration cannot be predicted yet without the freeze-thaw test. Since the contents of absorbed water and ratio between adsorbed and bulk water (of which the absorbed water consists) is controlled by the porosity and pore structure, it can be concluded that the deterioration of some rocks is strongly related to rock pore structure.
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Ogrodowska, Karolina, Karolina Łuszcz, and Andrzej Garbacz. "The effect of temperature on the mechanical properties of hybrid FRP bars applicable for the reinforcing of concrete structures." MATEC Web of Conferences 322 (2020): 01029. http://dx.doi.org/10.1051/matecconf/202032201029.
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One of the most common causes of the deterioration of concrete structures is the corrosion of steel reinforcement. Reinforcement made from fiber reinforced polymers (FRP) is considered to be an attractive substitution for traditional reinforcement. The most popular FRP reinforcing bars are made of glass fibers. Basalt fiber reinforced polymer (BFRP) is a relatively new material for reinforcing bars. The main drawback of BFRP bars is their low modulus of elasticity. A new type of bar made from hybrid fiber reinforced polymer (HFRP) in which a proportion of the basalt fibers are replaced with carbon fibers can be considered as a solution to this issue; such a bar is presented in this work. The HFRP bars might be treated as a relatively simple modification to previously produced BFRP bars. A different technical characteristic of the fibre reinforced polymer makes the designing of structures with FRP reinforcement differ from conventional reinforced concrete design. Therefore, it is necessary to identify the differences and limitations of their use in concrete structures, taking into account their material and geometric features. Despite the predominance of FRP composites in such aspects as corrosion resistance, high tensile strength, and significant weight reductions of structures – it is necessary to consider the behavior of FRP composites at elevated temperatures. In this paper, the effect of temperature on the mechanical properties of FRP bars was investigated. Three types of FRP bar were tested: BFRP, HFRP in which 25% of basalt fibers were replaced with carbon fibers and nHFRP in which epoxy resin was additionally modified with a nanosilica admixture. The mechanical properties were determined using ASTM standard testing for transverse shear strength. The tests were performed at -20°C, +20°C, +80°C for three diameters of each types of bar.
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Yu, Jianqiao, Hongxia Qiao, Theogene Hakuzweyezu, and Feifei Zhu. "Damage and Deterioration Model of Basalt Fiber/Magnesium Oxychloride Composites Based on GM(1, 1)-Markov in the Salt Spray Corrosion Environment." Journal of Renewable Materials 10, no. 7 (2022): 1–15. http://dx.doi.org/10.32604/jrm.2022.019620.
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E, Guangxun, Jizhe Zhang, Quanjun Shen, Ping Ji, Jing Wang, and Yushuai Xiao. "Influence of Filler Type and Rheological Properties of Asphalt Mastic on the Asphalt Mastic–Aggregate Interaction." Materials 16, no. 2 (January 6, 2023): 574. http://dx.doi.org/10.3390/ma16020574.
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The asphalt mastic–aggregate interaction plays an important role in the overall properties of asphalt mixtures and their durability in service in flexible pavements. This paper aims to study the influence of the physico-chemical features of fillers and the rheological properties of asphalt mastics on the bonding behavior between asphalt and aggregate, and the interfacial deterioration mechanism when subjected to static water immersion and pressured water immersion. It was found that the filler type (limestone powder, basalt powder, and granite powder) had a certain influence on the complex modulus of asphalt mastics, and its pore volume and specific surface area had significant effects on the phase angles and permeability of asphalt mastics. The effect of water pressure can accelerate the deterioration of bond strength of the asphalt mastic–aggregate interface in the short term, indicating that the dynamic water pressure generated by the driving load promotes the water damage process in asphalt pavements. In comparison, the residual bond strength ratio of the granite–asphalt mastic aggregate was the highest, while its bond strength was lower than that of the interface between limestone–asphalt mastics and limestone aggregate. This demonstrated that a low asphalt mastic complex modulus and a high phase angle are helpful in improving the durability of asphalt mixtures subjected to static and pressured water immersion conditions.
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Pai, Yogeesha, Dayananda Pai K, and M. Vijaya Kini. "Evaluation of the mechanical characteristics of hygrothermally aged 2-D basalt-aramid/epoxy hybrid interply composites." Journal of Physics: Conference Series 2070, no. 1 (November 1, 2021): 012234. http://dx.doi.org/10.1088/1742-6596/2070/1/012234.
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Abstract Polymer composites used in outdoor applications are exposed to environmental factors such as temperature and moisture which may affect the mechanical performance of the composites. In this study, the influence of moisture absorption on the mechanical properties of basalt-aramid/epoxy hybrid interply composites were evaluated. Two different types hybrid interply composites were taken for the investigation namely (301 A/03 B/301 A) and (451 A/03B/451 A). Composites were prepared using compression molding process and cut specimens were subjected to three different ageing environments for 180 days. Selected ageing conditions are, (i) ambient temperature ageing (ii) Sub-zero temperature ageing (−10°C) and (iii) Humid temperature ageing (40°C and 60% Relative humidity). Mechanical tests of the aged composites were carried out to analyse the behaviour of the composites. Moisture uptake of the specimens follow Fick’s law of diffusion with saturation absorption of 5.44%, 3.12% and 1.80% for ambient, sub-zero and humid specimens respectively. Results revealed that (301 a/03 B/301 a) aged composites possess higher mechanical properties compared to (451 a/03 B/451 a) aged composites. Highest reduction in properties were observed in ambient aged specimens followed by humid and sub-zero specimens. Scanning electron microscopy (SEM) was employed to observe the damage modes of the fractured specimens. Matrix deterioration, micro cracks and fibre fracture were the major types of failures observed in aged laminates.
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Zheng, Qianqian, and Jingshuang Zhang. "Mechanical properties and pore structure of basalt–polypropylene fiber fly ash concrete exposed to high temperatures." AIP Advances 12, no. 8 (August 1, 2022): 085025. http://dx.doi.org/10.1063/5.0099151.
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The deterioration of concrete structures after fires has been widely concerned. The purpose of this paper is to study the influence of high temperature on the mechanical properties and pore structure of hybrid basalt–polypropylene fiber fly ash concrete. The mechanical properties and damage amount of hybrid basalt–polypropylene fiber concrete with different content of fly ash (FA0, FA10, FA20, and FA30) at different temperatures (20, 200, 400, 600, and 800 °C) were investigated. Additionally, the pore structure test was conducted, and the relationship between pore structure parameters and macromechanical properties was analyzed. The microstructure at different temperatures was observed by scanning electron microscopy (SEM) images. Finally, the main pore structure parameters affecting compressive strength, tensile strength, and damage amount were determined by using the gray correlation entropy method. From the results, after natural cooling at 200 °C, the compressive and tensile strength of concrete was slightly higher than that at room temperature, and it should be noticed that the FA10 concrete specimen showed better mechanical properties at different temperatures compared with other specimens. The increase in air content, spacing factor, and average chord length weakened the strength of concrete, while the increase in specific surface area had a positive impact on the compressive and tensile strength of concrete. The microstructure of FA10 at high temperature was better than that of FA0. The specific surface area was the main factor affecting the compressive and tensile strength, while the main factor affecting the damage amount was the spacing factor, followed by the average chord length.
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Razjigaeva, N. G., L. A. Ganzey, T. A. Grebennikova, L. M. Mokhova, and T. A. Kopoteva. "Origin, age and development of mountain lakes of southern Far East during the Holocene monsoon variations." Limnology and Freshwater Biology, no. 4 (2022): 1538–40. http://dx.doi.org/10.31951/2658-3518-2022-a-4-1538.
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Abstract. A small mountain lakes-mire complex recorded in details Holocene environmental changes controlled by monsoon intensity and cyclogenesis activity. The reconstructions were based on multi-proxy studies (diatom, botanical and pollen analyses). We studied evolution of 8 lakes, located on different altitudes (from 320 to 1600 m). The studied lakes belong to four genetic types (on ancient basalt plateaus, depressions within large landslides on ancient volcano slopes and river valleys, and nival lakes on mountain peaks). Longest records (~9720 yr) of climatic changes was restored for East Manchurian mountains. Period long-term droughts 3050 1075 yr BP was connected with weaking of summer monsoon. Studied lakes of Sikhote-Alin were formed in late Holocene. The data clearly indicated drying events caused by precipitation deficits coincided with climate deterioration. Flood recurrence and cyclogenesis activity were recorded in the lake-mire complex developed on landslides within river valleys.
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Alzeebaree, Radhwan, Abdulkadir Çevik, Alaa Mohammedameen, Anıl Niş, and Mehmet Eren Gülşan. "Mechanical performance of FRP-confined geopolymer concrete under seawater attack." Advances in Structural Engineering 23, no. 6 (November 14, 2019): 1055–73. http://dx.doi.org/10.1177/1369433219886964.
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In the study, mechanical properties and durability performance of confined/unconfined geopolymer concrete and ordinary concrete specimens were investigated under ambient and seawater environments. Some of the specimens were confined by carbon fiber and basalt fiber–reinforced polymer fabric materials with one layer and three layers under chloride and ambient environments to observe mechanical strength contribution and durability performances of these hybrid types of materials. These fiber-reinforced polymer fabric materials were also evaluated in terms of retrofit purposes especially in the marine structures. In addition, microstructural evaluation is also conducted using scanning electron microscope on geopolymer concrete and ordinary concrete specimens to observe the amount of deterioration in microscale due to the chloride attacks. Results indicated that confined specimens exhibited enhanced strength, ductility, and durability properties than unconfined specimens, and the degree of the enhancement depended on the fiber-reinforced polymer confinement type and the number of fiber-reinforced polymer layer. Specimens confined by carbon fabrics with three layers showed superior mechanical properties and durability performance against chloride attack, while specimens confined by basalt fabrics with one layer exhibited low performance, and unconfined specimens showed the worst performance. Both fiber-reinforced polymer fabric materials can be utilized as retrofit materials in structural elements against chloride attacks. The results also pointed out that seawater attack reduced the ductility performance of the geopolymer concrete and ordinary concrete specimens. Furthermore, geopolymer concrete specimens were found more durable than the ordinary concrete specimens, and both types of concretes exhibited similar fracture properties, indicating that geopolymer concrete can be utilized for structural elements instead of ordinary concretes.
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Xie, Yan, Kunhua Guan, and Lin Lai. "Effect of Chloride on Tensile and Bending Capacities of Basalt FRP Mesh Reinforced Cementitious Thin Plates under Indoor and Marine Environments." International Journal of Polymer Science 2016 (2016): 1–7. http://dx.doi.org/10.1155/2016/7162313.
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This paper presented a durability experimental study for thin basalt fiber reinforced polymer (BFRP) mesh reinforced cementitious plates under indoor and marine environment. The marine environment was simulated by wetting/drying cycles (wetting in salt water and drying in hot air). After 12 months of exposure, the effects of the chloride on the tensile and bending behaviors of the thin plate were investigated. In addition to the penetration of salt water, the chloride in the thin plate could be also from the sea sand since it is a component of the plate. Experimental results showed that the effect of the indoor exposure on the tensile capacity of the plate is not pronounced, while the marine exposure reduced the tensile capacity significantly. The bending capacity of the thin plates was remarkably reduced by both indoor and marine environmental exposure, in which the effect of the marine environment is more severe. The tensile capacity of the meshes extracted from the thin plates was tested, as well as the meshes immersed in salt solution for 30, 60, and 90 days. The test results confirmed that the chloride is the reason of the BFRP mesh deterioration. Moreover, as a comparison, the steel mesh reinforced thin plate was also tested and it has a similar durability performance.
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A. Aboul-Nour, Louay, Ragab S. Mahmoud, Mahmoud A. Khater, and Nesma M. Moselhy. "Reinforcement alternatives for beams under cyclic load." International Journal of Engineering & Technology 9, no. 2 (April 3, 2020): 350. http://dx.doi.org/10.14419/ijet.v9i2.30350.
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The major cause of concrete structures deterioration is steel corrosion. Consequently, this situation has led researchers to study and test other reinforcement alternatives that are noncorrosive in nature. Rapidly emerging developments in the field of material technology has led to the development of fiber reinforced polymers (FRP). This research focuses on the flexural behavior of carbon, glass, aramid, and basalt (CFRP, GFRP, AFRP, and BFRP) fiber reinforced polymers bars as alternatives to the traditional steel reinforcement in concrete. The study involves a nonlinear numerical finite element analysis of a simply supported reinforced concrete beams subjected to cyclic loading, where the ANSYS program is utilized. The numerical model verification is executed on the experimental beams for ensuring the efficiency of ma-terial models, cyclic loading and various elements. Hysteresis curves are produced for each beam and analyzed, where loads, deflections, and cracks propagation are inspected and discussed. The results reveal that, the full replacement of traditional steel bars with CFRP bars gives the greatest increase in the ultimate load capacity by 38.5%. Also, other results are summarized in this paper.
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Li, Guowei, Sidi Kabba Bakarr, Jingqiu Wang, Xue Liu, and Chengyu Hong. "Effect of Stress Corrosion on Relaxation of Large Diameter BGFRP Bars." International Journal of Corrosion 2018 (December 2, 2018): 1–8. http://dx.doi.org/10.1155/2018/3418596.
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Fibre reinforced polymer (FRP) rebars do not corrode like steel rebars when they are exposed to moisture such as water. Instead they have been shown to degrade when exposed to alkaline media and, in some cases, acids. It has especially demonstrated extensive deterioration when it has been simultaneously stressed and exposed to harsh environments. This combined effect has been termed as stress corrosion. The effect of stress corrosion on the stress relaxation of large sized prestressed basalt-glass fibre reinforced polymer (BGFRP) bars was analyzed by laboratory experiments. Two stressed bars were submerged in aqueous solutions of acid and alkaline in two separate plastic tanks under constant strain. Stress reduction values were observed over a period of about 7 months. Bars immersed in acid bath had an average stress relaxation of 9.2% and that in the alkali bath was observed to be about 13.4%. These results support earlier assertions that exposure of GFRP bars to alkali media is likely to be detrimental to the long-term durability of the reinforced structure.
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Wang, Wensheng, Wenlei Xia, and Jiaxiang Liang. "Compressive and Tensile Fracture Failure Analysis of Asphalt Mixture Subjected to Freeze–Thaw Conditions by Acoustic Emission and CT Scanning Technologies." Applied Sciences 12, no. 21 (October 22, 2022): 10707. http://dx.doi.org/10.3390/app122110707.
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The cracking of bitumen pavement in seasonal frozen areas has direct and significant influences on its properties. In order to study the compressive and tensile fracture failure features of basalt fiber-reinforced asphalt mix after freeze–thaw (F-T) treatment, the load–displacement curves under the compression and tensile modes of asphalt mixture after F-T conditions were tested. As a real-time detection means, acoustic emission (AE) was used for testing asphalt mix under compression and tensile load modes. X-ray computed tomography (CT) was employed to represent and evaluate the interior void in F-T conditions. The results showed that, as F-T conditions continue, the compressive and tensile strength of the specimens at different temperatures decreases. The amplitude and count of AE signals with the time history of load level show different characteristics of change in various intervals. AE signal indirect parameters reveal that under compressive and tensile load modes there is a gradual deterioration of performance for asphalt mix due to the coupling interactions between tensile and shear cracks. The asphalt mixtures have different behavior in F-T conditions, which are attributable to interior meso-void characteristics based on CT analysis. This study is limited to the type and loading mode of asphalt mixture in order to quantitatively predict the performance of asphalt mixture.
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Liu, Zi-Lu, Ye Li, Xin-Ming Chen, and Hua-Zhe Jiao. "Study on Influence Mechanism of Short-Cut BF Dispersion Morphological Behavior on Concrete Properties Based on Meso Scale." Materials 15, no. 8 (April 11, 2022): 2788. http://dx.doi.org/10.3390/ma15082788.
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The orientation, distribution, and contact point density of BF (basalt fiber) in the concrete matrix play significant roles in the mechanical properties of BF concrete, but represent a weak point in current research. It is meaningful to study the morphological characteristics of BF in concrete. In this study, the transparent model test and joint blocking method were innovatively adopted to investigate the correlation of dosage with the BF morphological parameters and concrete mechanical properties. A focus on a BF dosage of 0–7.5 kg/m3 and the contribution index of fibers Cf was defined. Furthermore, NMR and CT techniques were used to observe the changes in the microstructure of BF concrete. The experimental results show that the BF contribution index Cf reaches the largest value when the BF content is around 3 kg/m3, approximately 2.7; in this case, the mechanical properties of BF concrete were also optimal, and the Cf was only 2.34 when the BF content was 7.5 kg/m3. NMR and CT test results show that there is a strong correlation between the BF morphological parameters and the distribution of pore structure in the concrete matrix. The overlapping contact of BF clusters led to the penetration of pores, which led the macro-pore proportion to increase dramatically. The increase in the macro-pore proportion is the main reason for the deterioration in concrete performance. In addition, these macro-pores may have adverse effects on the chloride ion permeability of BF concrete.
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Hagos, Ermias, Amare Girmay, and Tesfamichael Gebreyohannes. "Potential of Shallow Groundwater for Household Level Irrigation Practices in Tahtay Koraro Woreda, Tigray, Northern Ethiopia." Momona Ethiopian Journal of Science 13, no. 1 (August 15, 2021): 43–66. http://dx.doi.org/10.4314/mejs.v13i1.3.
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This paper deals with the results of a pilot study conducted to estimate the shallow groundwater resource potential and irrigation capacity at the household level in Tahtay Koraro Woreda, northwestern zone of Tigray, Ethiopia. The potential evapotranspiration and actual evapotranspiration of the study area are estimated to be 1484 mm/year and 814 mm/year respectively. The runoff is approximately calculated to be 280 mm/year and the annual groundwater recharge is estimated to be 29 mm/year. The total annual groundwater abstraction for human, livestock, and irrigation is estimated to be 25 mm/year. It should be noted that the groundwater recharge rate is expected to remain constant while the total annual groundwater discharge is expected to increase from year to year. This relation when projected over a long period may result in a negative groundwater budget which can result in depletion of groundwater (lowering of groundwater levels), reduced baseflow to streams, and deterioration of water quality. The computed values for hydraulic conductivity of the aquifers range from 1.63 m/day to 7.27 m/day with an average value of 4.9 m/day and transmissivity from 48.9 m2/day to 218.1 m2/day with an average value of 147.14 m2/day. The aquifers in the highly weathered basalt and highly weathered siltstone – sandstone intercalation have transmissivity values ranging from 99 m2/day to 218.1 m2/day with an average value of 157 m2/day and are grouped into the moderate potentiality aquifers category. The aquifers in the slightly weathered and fractured metavolcanics grouped under low potentiality based on the lower transmissivity values (<50 m2/day). The study area has low to moderate groundwater potentiality, hence, large-scale groundwater pumping is not possible. Therefore, the current activity of using hand dug wells for household-level irrigation is the best way of using groundwater for irrigation and other uses as well. Increasing the depth of the existing hand dug wells that are constructed in highly weathered basalt and highly weathered siltstone – sandstone intercalation can also enhance the yield of the hand dug wells. It is recommended to use water-saving irrigation technologies rather than increasing the number of wells. This will also help in increasing the irrigation area. Groundwater recharge enhancement structures such as trenches, percolation ponds, and check dams be constructed in scientifically selected localities to further enhance the groundwater potential.
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Huang, Yiwei, Xiaoyun Sun, Yinping Yao, Yejun Chen, Yan Chen, and Yuping He. "Compressed Sensing Algorithm-Based Magnetic Resonance Imaging Guided for Prognosis of Early Neurological Deterioration after Intravenous Thrombolysis in Ischemic Stroke Patients." Scientific Programming 2021 (July 6, 2021): 1–6. http://dx.doi.org/10.1155/2021/9568856.
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This work was aimed to study the risk factors and prognostic treatment for acute ischemic stroke (AIS) patients with early neurological deterioration (END) after intravenous thrombolytic therapy via compressed sensing algorithm-based magnetic resonance imaging (CS-MRI). 231 patients who were diagnosed with AIS were selected, and the final involved number of patients was 182. Patients with AIS were treated with intravenous thrombolysis with alteplase within 4.5 hours of onset. After treatment, patients with early neurological deterioration were defined as the deteriorating group and those without early neurological impairment were defined as the nondeteriorating group. In univariate analysis, hypertension, white blood cell count, and National Institutes of Health Stroke Scale (NIHSS) score were correlated with the occurrence of END. Under the CS-MRI theory, the two groups of patients were evaluated for middle cerebral artery basal ganglia infarction and internal watershed infarction. After univariate analysis, the P < 0.1 variables were taken as the independent variable, and the binary logistic regression model was adopted for multivariate regression analysis. It was disclosed that NIHSS score was not correlated with the occurrence of early neurological function deterioration, while homocysteine was. Hypertension, white blood cell count, homocysteine, and NIHSS score were risk factors for END. The image analysis revealed that the incidence of deteriorating basal ganglia infarction group was lower relative to the nondeteriorating group, and the incidence of watershed infarction was higher in the deteriorating group versus the nondeteriorating group. The image analysis suggested that predicting the occurrence of END through risk factors can actively provide endovascular treatment for patients with AIS.
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Masoud, A. A., G. Christidis, and K. Koike. "Characterization of El-Tih kaolin quality using mineralogical, geochemical and geostatistical analyses." Clay Minerals 48, no. 1 (March 2013): 1–20. http://dx.doi.org/10.1180/claymin.2013.048.1.01.
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AbstractDetailed multi-scale characterization of the kaolin quality and the controlling depositional environment is crucial for optimal quality upgrading and for prioritizing potential exploitation areas. In the present work, the quality of El-Tih kaolin, Egypt, was investigated using the chemical/mineralogical characteristics as well as the field observations of the clay. Chemical analysis of major oxides was carried out using energy dispersive X-ray fluorescence (EDS-XRF) spectrometry. Mineralogical analyses were carried out using X-ray diffraction (XRD) and scanning electron microscopy coupled with wavelength-dispersive X-ray spectroscopy (SEM-WDS). Spatial heterogeneity of the quality was evaluated applying kriging geostatistical techniques and potential zones were identified.Results clarified an upward gradual deterioration of the quality via a decrease in the Al2O3content and thickness of the clay layers, and an increase in the TiO2content. According to the kriging maps, areas of high potentiality indices (PI) characterized by high Al2O3and low SiO2content and maximum thickness of the kaolin are located to the west and east, and decrease toward the central part of the study area. The high PI zones are dominated by pseudo-hexagonal platy kaolinite, often forming accordion- and book-like aggregates with subordinate quartz and traces of Fe and Ti oxides, yielding minimal TiO2and Fe2O3contents. These zones of high PI are considered optimal for exploitation. Kaolinite was formed as a result of intensive weathering of rhyolite/granite and basalt in the source area, and subsequent erosion, transportation and deposition of the weathering mantles in a flood environment with marked depositional energy variations. Results allowed comparison with worldwide kaolin occurrences, and suggested the suitability of the studied kaolins for use in paper coating and filling and in higher-grade ceramics, after removal of free Fe- and Ti-oxide impurities.
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Barczewski, Mateusz, Aleksander Hejna, Kamila Sałasińska, Joanna Aniśko, Adam Piasecki, Katarzyna Skórczewska, and Jacek Andrzejewski. "Thermomechanical and Fire Properties of Polyethylene-Composite-Filled Ammonium Polyphosphate and Inorganic Fillers: An Evaluation of Their Modification Efficiency." Polymers 14, no. 12 (June 20, 2022): 2501. http://dx.doi.org/10.3390/polym14122501.
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The development of new polymer compositions characterized by a reduced environmental impact while lowering the price for applications in large-scale production requires the search for solutions based on the reduction in the polymer content in composites’ structure, as well as the use of fillers from sustainable sources. The study aimed to comprehensively evaluate introducing low-cost inorganic fillers, such as copper slag (CS), basalt powder (BP), and expanded vermiculite (VM), into the flame-retarded ammonium polyphosphate polyethylene composition (PE/APP). The addition of fillers (5–20 wt%) increased the stiffness and hardness of PE/APP, both at room and at elevated temperatures, which may increase the applicability range of the flame retardant polyethylene. The deterioration of composites’ tensile strength and impact strength induced by the presence of inorganic fillers compared to the unmodified polymer is described in detail. The addition of BP, CS, and VM with the simultaneous participation of APP with a total share of 40 wt% caused only a 3.1, 4.6, and 3 MPa decrease in the tensile strength compared to the reference value of 23 MPa found for PE. In turn, the cone calorimeter measurements allowed for the observation of a synergistic effect between APP and VM, reducing the peak heat rate release (pHRR) by 60% compared to unmodified PE. Incorporating fillers with a similar thermal stability but differing particle size distribution and shape led to additional information on their effectiveness in changing the properties of polyethylene. Critical examinations of changes in the mechanical and thermomechanical properties related to the structure analysis enabled the definition of the potential application perspectives analyzed in terms of burning behavior in a cone calorimetry test. Adding inorganic fillers derived from waste significantly reduces the flammability of composites with a matrix of thermoplastic polymers while increasing their sustainability and lowering their price without considerably reducing their mechanical properties, which allows for assigning developed materials as a replacement for flame-retarded polyethylene in large-scale non-loaded parts.
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Wataya, Takafumi, Ryuji Ishizaki, Masashi Kitagawa, and Yuzuru Tashiro. "Germinoma in the bilateral basal ganglia presented with cognitive deterioration." Child's Nervous System 31, no. 6 (January 11, 2015): 953–58. http://dx.doi.org/10.1007/s00381-015-2616-7.
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Papaioannou, Ourania, Theodoros Karampitsakos, Fotios Sampsonas, and Argyrios Tzouvelekis. "Fanconi syndrome-associated interstitial lung disease." BMJ Case Reports 15, no. 7 (July 2022): e249242. http://dx.doi.org/10.1136/bcr-2022-249242.
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A middle-aged man was referred to our respiratory department with dyspnoea progressively deteriorating and non-productive cough over the past 8 months. High-resolution CT revealed multiple bilateral consolidations, traction bronchiectasis, reticular pattern and honeycombing with basal and peripheral predominance. Serology tests were negative. Pulmonary function tests showed moderate restrictive functional impairment and severe reduction in diffusing capacity for carbon monoxide. Meticulous evaluation of patient’s medical history revealed recent administration of oral corticosteroid due to pulmonary fibrosis potentially in the context of Fanconi syndrome diagnosed at childhood. The working diagnosis of interstitial lung disease (ILD) as a rare complication of Fanconi syndrome was proposed following multidisciplinary discussion. Despite combination treatment with low doses of corticosteroids and antifibrotic compound, the patient exhibited clinical, radiological and functional deterioration, was admitted to intensive care unit due to respiratory failure following infection-driven progression of fibrotic ILD and finally died.
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Gross, Bradley A., Edward R. Smith, and R. Michael Scott. "Cavernous malformations of the basal ganglia in children." Journal of Neurosurgery: Pediatrics 12, no. 2 (August 2013): 171–74. http://dx.doi.org/10.3171/2013.5.peds1335.
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Object Cavernous malformations (CMs) of the basal ganglia are relatively rare lesions that can lead to considerable neurological impairment because of their eloquent location. The authors reviewed the clinical course and surgical outcome of a series of children with basal ganglia CMs. Methods The authors retrospectively reviewed the operative experience of the senior author (R.M.S.) and the 1997–2011 database of Boston Children's Hospital for children with CM of the basal ganglia (which includes CM of the caudate and/or lentiform nucleus and excludes CM of the thalamus). They evaluated baseline demographics, presenting signs, operative outcomes, and condition at long-term follow-up visits and compared these characteristics among patients who underwent surgery and those who were observed. Results Of 180 children with a diagnosis of CM, 11 (6%) had CM of the basal ganglia. The mean age at diagnosis was 9.3 years, and the male/female ratio was 1.8:1. Presenting signs were as follows: hemorrhage (8 children), incidental lesions (2), and seizures (1); 2 children had choreiform movement disorders. Treatment was observation or surgery. Observation was chosen for 5 children either because the lesions were asymptomatic (2 children) or because the risk for neurological dysfunction after attempted excision was believed to be high (3 children). These 5 children were observed over a combined total of 30.4 patient-years; none experienced neurological deterioration or symptomatic hemorrhage from their lesions. The other 6 children underwent microsurgical resection of the lesion because they were symptomatic from hemorrhage or increasing mass effect. All 6 of these children had hemorrhagic lesions, of which the smallest dimension was at least 1.5 cm. Of these 6 lesions, 5 were excised completely, and over a combined total of 46 patient-years of follow-up, no rebleeding or late neurological deterioration after surgery was reported. Conclusions In this patient population, the natural history of small and asymptomatic CMs of the basal ganglia was benign. The children with large (> 1.5 cm) symptomatic lesions underwent excision; neurological impairment was apparently minimal, and no hemorrhage or neurological deterioration occurred later.
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Alvarez, Carmen, Danielle Bailbe, Françoise Picarel-Blanchot, Eric Bertin, Ana-Maria Pascual-Leone, and Bernard Portha. "Effect of early dietary restriction on insulin action and secretion in the GK rat, a spontaneous model of NIDDM." American Journal of Physiology-Endocrinology and Metabolism 278, no. 6 (June 1, 2000): E1097—E1103. http://dx.doi.org/10.1152/ajpendo.2000.278.6.e1097.
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The availability of the Goto-Kakisaki (GK) rat model of non-insulin-dependent diabetes mellitus prompted us to test the effect of a limited period of undernutrition in previously diabetic young rats on their insulin secretion and insulin action during adult age. Four-week-old female GK rats were either food restricted (35% restriction, 15% protein diet) or protein and energy restricted (35% restriction, 5% protein diet) for 4 wk. Food restriction in the young GK rat lowered weight gain but did not aggravate basal hyperglycemia or glucose intolerance, despite a decrease in basal plasma insulin level. Furthermore, the insulin-mediated glucose uptake by peripheral tissues in the GK rat was clearly improved. We also found that food restriction, when it is coupled to overt protein deficiency in the young GK rat, altered weight gain more severely and slightly decreased basal hyperglycemia but conversely aggravated glucose tolerance. Improvement of basal hyperglycemia was related to repression of basal hepatic glucose hyperproduction, despite profound attenuation of basal plasma insulin level. Deterioration of tolerance to glucose was related to severe blunting of the residual glucose-induced insulin secretion. It is, however, likely that the important enhancement of the insulin-mediated glucose uptake helped to limit the deterioration of glucose tolerance.
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Man, Honghao, Yuhua Bi, Yongpeng Yu, Shengwu Wang, Zhenming Zhao, Xiaohong Qiao, and Weiping Ju. "Associated factors of early neurological deterioration in isolated acute lacunar infarction in basal ganglia." Journal of Neurorestoratology 7, no. 2 (2019): 63–69. http://dx.doi.org/10.26599/jnr.2019.9040007.
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Objective:To investigate, in basal ganglia, the factors associated with early neurological deterioration (END) of isolated acute lacunar infarction.Methods:167 patients, in the retrospective group, with isolated acute lacunar infarction in basal ganglia, were defined by magnetic resonance imaging (MRI). The National Institutes of Health Stroke Scale (NIHSS) defined early neurological deterioration as increases of ≥ 2 within 72 hours following admission. Baseline variables predicting END were investigated with multivariate logistic regression analysis.Results:In the study, END occurred in 42 (25.15%) patients. Lesions located in posterior limb of internal capsule were independent risk factors for END (P < 0.01). Associated with END were the age of onset, history of cerebral infarction, history of diabetes, systolic blood pressure at admission and lesions of cerebral white matter. This presented significant differences (P < 0.05). With or without diabetes and different lesion location at varying layers and inter-layers, single-factor and multi-factor analysis revealed no effect on the association between positive ENT and age, history of stroke, white matter. Previous history of stroke, pathological changes of white matter, and age of onset, correlates with END which showed significant difference (P < 0.05).Conclusions:There is a close relationship between the lesion location and other related factors, such as lesions of cerebral white matter, history of cerebral infarction, history of diabetes and age, etc. and END in patients with isolated acute lacunar infarction in basal ganglia. Protective factors of END included age ≥ 65, high systolic pressure, stroke history, cerebral white matter lesions in our study.
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Iaccarino, Corrado, Paolo Schiavi, Edoardo Picetti, Matteo Goldoni, Davide Cerasti, Marialuisa Caspani, and Franco Servadei. "Patients with brain contusions: predictors of outcome and relationship between radiological and clinical evolution." Journal of Neurosurgery 120, no. 4 (April 2014): 908–18. http://dx.doi.org/10.3171/2013.12.jns131090.
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Object Traumatic parenchymal mass lesions are common sequelae of traumatic brain injuries (TBIs). They occur in up to 8.2% of all TBI cases and 13%–35% of severe TBI cases, and they account for up to 20% of surgical intracranial lesions. Controversy exists concerning the association between radiological and clinical evolution of brain contusions. The aim of this study was to identify predictors of unfavorable outcome, analyze the evolution of brain contusions, and evaluate specific indications for surgery. Methods In a retrospective, multicenter study, patients with brain contusions were identified in separate patient cohorts from 11 hospitals over a 4-year period (2008–2011). Data on clinical parameters and course of the contusion were collected. Radiological parameters were registered by using CT images taken at the time of hospital admission and at subsequent follow-up times. Patients who underwent surgical procedures were identified. Outcomes were evaluated 6 months after trauma by using the Glasgow Outcome Scale-Extended. Results Multivariate analysis revealed the following reliable predictors of unfavorable outcome: 1) increased patient age, 2) lower Glasgow Coma Scale score at first evaluation, 3) clinical deterioration in the first hours after trauma, and 4) onset or increase of midline shift on follow-up CT images. Further multivariate analysis identified the following as statistically significant predictors of clinical deterioration during the first hours after trauma: 1) onset of or increase in midline shift on follow-up CT images (p < 0.001) and 2) increased effacement of basal cisterns on follow-up CT images (p < 0.001). Conclusions In TBI patients with cerebral contusion, the onset of clinical deterioration is predictably associated with the onset or increase of midline shift and worsened status of basal cisterns but not with hematoma or edema volume increase. A combination of clinical deterioration and increased midline shift/basal cistern compression is the most reasonable indicator for surgery.
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Park, Jong-Ho, Han-Joon Kim, and Seong-Min Kim. "Acute Chorea with Bilateral Basal Ganglia Lesions in Diabetic Uremia." Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques 34, no. 2 (May 2007): 248–50. http://dx.doi.org/10.1017/s0317167100006144.
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Uremia is a syndrome of clinical and metabolic abnormalities, which develops in parallel with the deterioration of renal function. Uremic encephalopathy is one of many manifestations of acute or chronic renal failure. It is usually applied to patients with cortical involvement, such as confusion, seizure, tremor, myoclonus, or asterixis. Some cases of acute extrapyramidal movement disorders associated with bilateral basal ganglia lesions, especially parkinsonism have been reported in uremic patients. Here, we report a diabetic uremic patient who developed acute chorea associated with bilateral basal ganglia lesions.
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Matta, André Palma da Cunha, and Márcia Cristina Antunes Ribas. "Hypomyelination with atrophy of the basal ganglia and cerebellum: case report." Arquivos de Neuro-Psiquiatria 65, no. 1 (March 2007): 161–63. http://dx.doi.org/10.1590/s0004-282x2007000100033.
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Hypomyelination with atrophy of the basal ganglia and cerebellum (H-ABC) is a rare disease that has been recently described. It must be remembered as a possible etiology of leukoencephalopathies in children. We describe a typical case of H-ABC in a 11-month-old boy. He presents with global development delay, oral dyskinesia, and global dystonia and spasticity. Magnetic resonance imaging disclosed typical features of H-ABC and clinical laboratory tests were all negative. A slow neurological deterioration has been detected with worsening of involuntary movements.
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Kobayashi, Kenichiro, Minoru Suehiro, Toshiro Maihara, Ikuya Usami, and Toshio Heike. "Excessive Salivation as a Hidden Comorbidity of Basal Ganglia Germ Cell Tumor." Journal of Pediatric Neurology 17, no. 05 (July 30, 2018): 187–90. http://dx.doi.org/10.1055/s-0038-1667196.
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AbstractThe progression of basal ganglia germ cell tumor (BGGCT) is slow and insidious, and the diagnosis is often delayed. We report here an 11-year-old boy with BGGCT associated with psychomotor deterioration and excessive salivation. Serial salivary gland scintigraphy and single photon emission computed tomography suggested that the dysregulation of basal ganglia to cortical circuitry accounts for the neurological comorbidity associated with BGGCT. We also found that topical scopolamine patches are safe and effective to suppress excessive salivation. Clinical Trial Registration: No.
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Behar, Joachim, and Yael Yaniv. "Age-related pacemaker deterioration is due to impaired intracellular and membrane mechanisms: Insights from numerical modeling." Journal of General Physiology 149, no. 10 (September 8, 2017): 935–49. http://dx.doi.org/10.1085/jgp.201711792.
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Age-related deterioration of pacemaker function has been documented in mammals, including humans. In aged isolated sinoatrial node tissues and cells, reduction in the spontaneous action potential (AP) firing rate was associated with deterioration of intracellular and membrane mechanisms; however, their relative contribution to age-associated deficient pacemaker function is not known. Interestingly, pharmacological interventions that increase posttranslation modification signaling activities can restore the basal and maximal AP firing rate, but the identities of the protein targets responsible for AP firing rate restoration are not known. Here, we developed a numerical model that simulates the function of a single mouse pacemaker cell. In addition to describing membrane and intracellular mechanisms, the model includes descriptions of autonomic receptor activation pathways and posttranslation modification signaling cascades. The numerical model shows that age-related deterioration of pacemaker function is related to impaired intracellular and membrane mechanisms: HCN4, T-type channels, and phospholamban functions, as well as the node connecting these mechanisms, i.e., intracellular Ca2+ and posttranslation modification signaling. To explain the restored maximal beating rate in response to maximal phosphodiesterase (PDE) inhibition, autonomic receptor stimulation, or infused cyclic adenosine monophosphate (cAMP), the model predicts that phospholamban phosphorylation by protein kinase A (PKA) and HCN4 sensitivity to cAMP are altered in advanced age. Moreover, alteration in PKA and cAMP sensitivity can also explain age-reduced sensitivity to PDE inhibition and autonomic receptor stimulation. Finally, the numerical model suggests two pharmacological approaches and one gene manipulation method to restore the basal beating rate of aged pacemaker cells to that of normal adult cells. In conclusion, our numerical model shows that impaired membrane and intracellular mechanisms and the nodes that couple them can lead to deteriorated pacemaker function. By increasing posttranslation modification signaling, the deteriorated basal and maximal age-associated beating rate can be restored to adult levels.
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Marçais, Benoit, and Olivier Caël. "Relation between Collybia fusipes root rot and growth of pedunculate oak." Canadian Journal of Forest Research 31, no. 5 (May 1, 2001): 757–64. http://dx.doi.org/10.1139/x01-007.
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Collybia fusipes (Bull. ex Fr.) is the cause of a root rot on oak, mainly pedunculate oak, Quercus robur L., and northern red oak, Quercus rubra L. The disease is associated with a deterioration of the crown of affected trees in some, but not all, stands. We investigated the relationship between the level of root damage induced by C. fusipes and past growth of the infected trees at four sites of pedunculate oaks and one site of red oaks in northeastern and central France. The severely infected oaks showed poor growth for 1550 years depending on the site. At one site where C. fusipes was not associated with a deterioration of the affected tree crowns, the basal area increments of severely root damaged oaks has nevertheless been poor for more than 30 years. Severe infection by C. fusipes was associated with a 3050% reduction of basal area increment in the last 10 years preceding the study at all the sites. In contrast, in all the sites, trees lightly damaged by C. fusipes had basal area increments similar to the undamaged trees. The data would be consistent with a disease that develops slowly on vigorous trees and affects their growth only late in the infection process.
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Nagesh, Madhusudhan, Kautilya Rajendrakumar Patel, Ajit Mishra, Ujwal Yeole, Andiperumal R. Prabhuraj, and Dhaval Shukla. "Role of repeat CT in mild to moderate head injury: an institutional study." Neurosurgical Focus 47, no. 5 (November 2019): E2. http://dx.doi.org/10.3171/2019.8.focus19527.
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OBJECTIVEPatients with traumatic brain injury (TBI) often undergo repeat head CT scans to identify the possible progression of injury. The objective of this study is to evaluate the need for routine repeat head CT scans in patients with mild to moderate head injury and an initial positive abnormal CT scan.METHODSThis is a retrospective study of patients presenting to the emergency department from January 2016 to December 2017 with Glasgow Coma Scale (GCS) scores > 8 and an initial abnormal CT scan, who underwent repeat CT during their in-hospital medical management. Patients who underwent surgery after the first CT scan, had a GCS score < 9, or had a normal initial CT scan were excluded. Demographic, medical history, and physical examination details were collected, and CT scans were reviewed. Radiological deterioration, neurological deterioration, and/or the need for neurosurgical intervention were the primary outcome variables.RESULTSA total of 1033 patients were included in this study. These patients underwent at least two CT scans on an inpatient basis. Of these 1033 patients, 54.1% had mild head injury and 45.9% had moderate head injury based on GCS score at admission. The most common diagnosis was contusion (43.8%), followed by extradural hematoma (28.8%) and subdural hematoma (26.6%). A total of 2636 CT scans were performed for 1033 patients, with a mean of 2.55 per patient. Of these, 25 (2.4%) had neurological deterioration, 90 (8.7%) had a progression of an existing lesion or appearance of a new lesion on repeat CT, and 101 (9.8%) required neurosurgical intervention. Seventy-five patients underwent surgery due to worsening of repeat CT without neurological deterioration, so the average number of repeat CT scans required to identify one such patient was 21.3. On multiple logistic regression, GCS score at admission (p = 0.024), abnormal international normalized ratio (INR; p < 0.001), midline shift (p = 0.005), effaced basal cisterns (p < 0.001), and multiple hemorrhagic lesions (p = 0.010) were associated with worsening of repeat CT, neurological deterioration, and/or need for neurosurgical intervention.CONCLUSIONSThe role of routine repeat head CT in medically managed patients with head injury is controversial. The authors have tried to study the various factors that are associated with neurological deterioration, radiological deterioration, and/or need for neurosurgical intervention. In this study the authors found lower GCS score at admission, abnormal INR, presence of midline shift, effaced basal cisterns, and multiple lesions on initial CT to be significantly associated with the above outcomes.