These results may be helpful in selecting the design and curing parameters for the purposes of maximizing the tensile properties of textile CAC composites.Cement composites (CC) are among the composites most widely used in the construction industry, such as a durable waterproof and fire-resistant concrete layer, slope protection, and application in retaining wall structures. The use of 3D fabric embedded in the cement media can improve the mechanical properties of the composites. The use of calcium aluminate cement (CAC) can accelerate the production process of the CC and further contribute to improving the mechanical properties of the cement media. The purpose of this study is to promote the use of these cementitious composites by deepening the knowledge of their tensile properties and investigating the factors that may affect them. Therefore, 270 specimens  were made, and the tensile properties, absorbed energy, and the inversion effects were evaluated. The results showed that the curing conditions of the reinforced cementitious composite in water with temperature values of 7, 23, and 50 °C affect the tensile behavior. The tensile strength of the CCs cured in water with a temperature of 23 °C had the highest tensile strength, while 7 and 50 °C produced a lower tensile strength. The inversion effect has been observed in CC at 23 °C between 7 and 28 days, while this effect has not occurred in other curing temperature values. By examining three commercial types of stitches in fabrics and the performance of the reinforced cementitious composites in the warp direction, it was found that the structure of the “Tuck Stitch” has higher tensile strength and absorbed energy compared to “Knit stitch” and “Miss Stitch”. The tensile strength and fracture energy of the CC reinforced with “Tuck Stitch” fabric in the warp direction, by curing in 23 °C water for 7 days, were found to be 2.81 MPa and 1.65 × 10 The development of lightweight composites with high tensile strength is gaining increasing attention by the industry in several sectors due to their versatility for numerous applications. As far as the construction industry is concerned, many composites, such as unreinforced concrete, have good compressive strength and poor tensile strength. However, by adding a reinforcing component, the tensile and flexural properties can be expected to improve. Textile reinforced concrete (TRC) has several advantages: tensile strength, good flexibility, low weight, low thickness, and corrosion resistance ,2. TheseReinforced cementitious composite with 3D fabric consists of spacer fabric and cementitious material. Spacer fabrics consist of two parallel fabrics connected by spacer yarns. The use of 3D fabrics, due to low weight and high volume, entailed the occupation of a large proportion of the overall cementitious composites, reduced the material consumption and, as a result, significantly reduced the weight of the composites. Reducing the consumption of materials is economical. On the other hand, usually, if too much bending or tensile load is applied, TRC composites will break but will not separate due to the bridging effect of fibers or fabric.Previous studies have shown that a variety of textiles have effectively reinforced concrete matrices. The use of fibers ,4, yarns2 emissions than OPC production [10 , which is thermodynamically unstable. With increasing temperature (between 30 to 70 °C), the product C2AH8 is semi-stable. At a temperature of more than 70 °C, the product C3AH6 is stable. Changing the phase from the unstable to the stable one reduces the volume and increases the porosity, thus reducing the strength [With regard to the types of cement, most researchers use Portland cement because of its low cost and greater availability. Still, recently, calcium aluminate cement (CAC) has been widespread. CAC is a particular type of cement considered in CC due to its unique properties . In thesoduction . At presoduction . Accordioduction ,23. The oduction ,25,26. Hoduction ,28. CAC oduction . The hydstrength . In varistrength ,10,11.Due to the effect of the water-to-cement ratio on the hydration rate  and cracAs mentioned, cement mortar has low tensile strength and fracture strain; therefore, TRC technology is used to reinforce cement mortar. Due to the spacer yarns, the reinforcement of cement mortar by knitted 3D fabrics has received much attention in the fabric structure. The role of using knitted 3D fabrics with spacer yarns on a smaller scale is similar to the position of using reinforcement to reinforce a concrete structure. Three-dimensional fabric acts as a reinforcing component that significantly improves the tensile strength. In addition to the type of fibers, the structure of the textiles, including yarn density, loop structures , 3D fabrBased on the considerations reported above regarding the potential benefits and possible influencing factors of 3D fabric-reinforced cementitious composites using calcium aluminate cement, the calcium aluminate cement was considered because of its higher strength at an early age. Because the inversion effect is important and unavoidable in calcium aluminate cement, the simultaneous effects of temperature and curing age in CAC mortar are investigated. In this regard, since 3D weft-knitted fabric machines are cheaper and easier to access than 3D warp-knitted fabric machines, therefore, in this study, the 3D weft-knitted fabric was used instead of a warp-knitted one, in addition to the effect of three different hole patterns (stitch structures) of the upper layer of the 3D fabrics in warp and weft directions on the tensile properties of the composite. This section details the characteristics of the textile-reinforced cementitious composites analyzed here and the type of tests adopted to study their performances. The final CC properties as 3D fabric-cemented composites depend mainly on 3D fabric cement media and the stitch structure. Therefore, three weft-knitted 3D fabric designs with the same polymeric yarn (Nylon-Polyester) were knitted. Three fabric stitches  were used in this experimental work to show the effect of the fabric structures on the tensile strength of the reinforced cementitious composites. For a more precise explanation of the details of the stitch structure and the shape of the holes of the outer layers of the 3D fabric, which is one of the essential components of the cement composite, .In the CCs, a knitted 3D fabric is used to strengthen a CAC-based cementitious matrix. The 3D fabric is considered a reinforcing component divided into the outer substrates and the monofilament spacer yarns that connect the two outer substrates. Three types of knitted 3D fabrics with different stitch patterns in outer layers have been used to investigate the effect of stitch structure on the tensile strength of the CC. The thickness of the fabrics was constant (5 mm) and contributed to reducing the weight of the CC (EN ISO 5084 ). The stDifferent shapes of fabric holes are caused by different stitch structures in the three fabrics, SF1-SF2-SF3. The form of the holes in the fabric changes with the stitch structure of the bottom layer of the 3D fabric and the movement of the knitting needles. In preparing these three types of fabrics, the density of monofilament yarns and the angle of their placement between two outer substrates are constant. Only the texture type of the bottom layer of the fabric is considered a variable factor.The approximate shapes of the holes in the bottom layer of SF1-SF2-SF3 were rectangular, parallelogram, and without regular geometric shape, respectively. The yarn fineness (Den) of the bottom layer of the fabric (mesh fabric) and the top layer of the fabric (solid fabric) are 150 Den and 150/8 Den, respectively, and the middle yarn fineness is 80/2 Den. In the SF1 fabric, which uses the “knit stitch” loop structure, all the loops were woven. In SF2, which uses a “miss stitch” loop structure, the needle releases the desired yarn and knits another yarn, and this occurs when the needle remains at rest for as long as a knit operation, and then in the next loop performs the knit. In SF3, with a “tuck stitch” loop structure, the needle holds the previous loop on the leg and takes the fed yarn, in which case the last loop does the knitting halfway, but it does not do the second half of the knit, which is releasing the loop, which is why this loop is called a tuck stitch. A schematic of all three types of stitch structures is shown in The cement mortar media’s chemical composition includes a combination of silica filler and CAC  and vibrates to make sure it is completely filled. This process of filling the fabric with dry cement matrix is almost similar to Li’s paper . A thin 3. Due to the structural difference of the stitch in the warp and weft direction of the 3D fabrics, a tensile test in each direction was performed separately with three repetitions. All specimens were kept at rest in the laboratory before testing.The tensile tests on yarn were performed with a Shirley Micro350 machine with a capacity of 250 KN. The related test speed was 10 mm/min, the distance between the clamps was 500 mm, and the Iranian standard 29   tensile tests are summarized in The spacer yarns provide a high stiffness to the 3D fabric. Therefore, by adding cementitious material into the 3D fabric from bottom-layer holes, despite the high weight of cementitious materials, the 3D fabric is not compressed, and its thickness does not decrease. Therefore, there is no space between the cementitious material and the layers of fabric. During the tensile test, the interaction of the tensile capacity of the spacer yarns and the upper/bottom layers of fabric are considered together. Therefore, the difference between the stiffness of the spacer yarns and the upper and bottom layers yarns should not be significant so as not to tear the stitches. Thus, the tensile Young’s modulus of the spacer yarn was about twice that of the yarn of the upper and bottom layers.The stress–strain curve for monofilament and multifilament yarns is shown in The tensile results of 3D fabrics in terms of warp and weft directions are shown in 10 to the stable phase of C3AH6 has weakened the molecular structure and thus reduced the hardness of the material and the ultimate tensile strength. This result is consistent with the result of Juenger’s research [To evaluate the influence of the temperature and curing age of cement mortar specimens on the tensile strength, cement mortar samples in standard molds were prepared and tested. The results in research .In this section, the tensile performance of reinforced cementitious composite is presented in Investigation of the different spacemen results in The results of the tensile test of the fabrics show that they are similar not only in the warp direction but also in the weft direction. In addition, the tensile behavior of reinforced cementitious composites with these fabrics was similar too. By comparing the mortar and CCs test results with each other, it can be concluded that the mortar had a lower tensile strength than the reinforced cementitious composite  due to reinforcement caused by the spacer yarns embedded within the mortar.According to the types of spacer fabric presented in By comparing the curves in In all three temperature conditions, it was observed that tensile stress was increased when increasing the curing age of the samples. However, at 23 °C, the tensile stress decreased at 28 days probably due to the inversion phenomenon. In all diagrams, the tensile behavior of CCs reinforced with fabrics SF1 and SF2 has almost the same performance. According to the results obtained from the effect of fabric tensile direction (warp or weft) on the tensile stress of the different CCs, the highest tensile strain was observed in the CC tensile in the warp direction due to greater freedom of movement in monofilament yarns.εf). The strain at the end of the test is denoted as “ultimate” strain (εu), and the ratio of fracture strain to ultimate strain is denoted as cross-sectional strain capacity. The above-defined quantities are reported in According to the results presented in The force–displacement curve integral was used to calculate the fracture energy of reinforced cementitious composites. The absorbed energy per unit area was calculated by integrating the area below the curve ,52. Figuu), then SF1 and finally SF2 had the lowest final strain regardless of the ages, curing temperature values, and different directions of the fabric. These results are also consistent with the fabric tension results (presented in f/εu) in different fabric directions. The cross-sectional strain capacity in the weft direction  for CCs reinforced with different fabrics is as follows: SF1 = 1, 0.59 < SF2 < 1 and 0.11 < SF3 < 0.37. It can be mentioned that the cross-sectional strain capacity was the highest for SF1 fabric-reinforced cementitious composites, followed by SF2 and finally SF3. On the other hand, the cross-sectional strain capacity in the warp direction  is highest for SF2 fabric-reinforced cementitious composites (0.7 < εf/εu < 0.9), followed by SF1 (0.5 < εf/εu < 0.9), and SF3 (0.3 < εf/εu < 0.6) was the lowest value. The results related to the absorbed energy up to the fracture strain point (maximum tensile stress) are presented in According to According to Three types of 3D fabric (SF1-SF2-SF3) with three different types of loop textures in the bottom layer of the fabric in terms of length and width were stretched, and the SF3 fabric had the highest tensile capacity and ductility compared to the other 3D fabrics. The SF1 had the least amount of stress and strain.By examining the amount of stress and strain in fabrics in both warp and weft directions, it was observed that reinforced CCs had higher tensile strength and lower strain in the weft direction than in the warp direction. This trend was observed in all three types of fabrics.This research aims to study simultaneous effects of temperature and curing age in CAC mortar and the three different hole patterns (stitch structures) of the bottom layer of the 3D fabrics in warp and weft directions on the tensile properties of the composite. Tensile tests have been performed to obtain warp and weft tensile stress–strain curves, and the fracture energy of the CC has been presented. To investigate and analyze the tensile behavior of reinforced cementitious composite, each of its components, including yarns, 3D fabrics, cement phase, and finally, reinforced composites, were subjected to tensile tests, and the behavior of each was examined separately. Three 3D fabrics with different stitch structures use in the bottom layer, and their effect on the tensile behavior of the CC was investigated. The stress-strain curves of the CCs in different directions (warp and weft), ages, and curing conditions were obtained, and the experimental results were analyzed. The results are presented as follows:Reinforced cementitious composites with 3D fabrics were studied on the basis of two features: the maximum tensile stress and the maximum absorbed energy. Examination of the ultimate tensile stress of reinforced cementitious CCs showed that the composites reinforced with SF3 have the highest tensile stress; then, CC reinforced with SF1 and reinforced with SF2 fabric. This trend was similar in terms of warp and weft direction. By examining the absorbed energy of reinforced cementitious composites, it was observed that the CCs reinforced with SF3 had the highest absorbed energy in the warp direction. Then SF1 and SF2 had the lowest absorbed energy. CCs reinforced with SF1 had the highest absorbed energy in the weft direction, and then SF2 while SF3 had the lowest absorbed energy.In this paper, the cement phase mixing design was considered fixed, and the method of achieving this mixing design is presented in a separate article. Different angles of spacer yarns in 3D fabric, yarn material, 3D fabric thickness, etc., could be influential factors that have not been studied in this article, and each can be examined separately in several articles. In this paper, reinforced cement composites were only tested for tensile strength. The results of composite bending tests along with their modeling and optimization by ABAQUS software will be present in future papers.


Grapevine rupestris stem pitting-associated virus (GRSPaV), Grapevine virus A (GVA), Grapevine leafroll-associated virus-1 (GLRaV-1), Grapevine leafroll-associated virus-2 (GLRaV-2), Grapevine leafroll-associated virus-3 (GLRaV-3), Grapevine fanleaf virus (GFLV), and Grapevine fleck virus (GFkV) using RT-PCR. Out of all samples tested, 54.5% were positive for at least one of the viruses  in the Stavropol region, 49.8% in the Krasnodar region and 49.5% in the Republic of Crimea. Some plants were found to be infected with several viruses simultaneously. In the Republic of Crimea, for instance, a number of plants were infected with five viruses. In the Krasnodar region and the Republic of Crimea, 4.7% and 3.3% of the samples were predominantly infected with both GFkV and GRSPaV, whereas in the Stavropol region, 6% of the selected samples had both GLRaV-1 and GVA infections. We carried out a phylogenetic analysis of the coat protein genes of the detected viruses and identified the presence of GVA of groups I and IV, GRSPaV of groups BS and SG1, GLRaV-1 of group III, GLRaV-2 of groups PN and H4, GLRaV-3 of groups I and III. The results obtained make it possible to assess the viral load and the distribution of the main grapevine viruses on plantations in the viticultural zones of Russia, emphasizing the urgent need to develop and implement long-term strategies for the control of viral diseases of grapes.Viral diseases can seriously damage the vineyard productivity and the quality of grape and wine products. Therefore, the study of the species composition and range of grapevine viruses is important for the development and implementation of strategies and tactics to limit their spread and increase the economic benefits of viticulture. In 2014–2019, we carried out a large-scale phytosanitary monitoring of Russian commercial vineyards in the Krasnodar region, Stavropol region and Republic of Crimea. A total of 1857 samples were collected and tested for the presence of  A large variety of fruits and berries provide humans with beneficial substances necessary for the vital activities of the body; moreover, some cultures, including grapes which is one of the most ancient and valuable fruit crops , are theClosteroviridae, Betaflexiviridae, Caulimoviridae, Geminiviridae, and Secoviridae. About half of viral phytopathogens are associated with four main disease complexes known as infectious degeneration and decline (fanleaf), leafroll, rugose wood, and fleck [Grapevine fanleaf virus (GFLV) and grapevine leafroll disease, the most significant infectious agents of which are Grapevine leafroll-associated virus-1 (GLRaV-1), Grapevine leafroll-associated virus-2 (GLRaV-2) and Grapevine leafroll-associated virus-3 (GLRaV-3) [Among woody plants worldwide, grapevine is the culture which is most affected by viral phytopathogens . To datend fleck ,7. The mGLRaV-3) ,9,10. ThGLRaV-3) . It is kGLRaV-3) ,12,13.Grapevine rupestris stem pitting-associated virus (GRSPaV), Grapevine virus A (GVA), Grapevine virus B (GVB), Grapevine virus D (GVD), Grapevine virus E (GVE), and Grapevine virus F (GVF). They are characterized by the presence of rupestris stem pitting, kober stem grooving, corky bark, and grooving and pitting of the woody cylinder [Viruses that cause rugose wood include cylinder . Infectecylinder .Grapevine fleck virus (GFkV) is one of four representatives of the fleck complex, along with Grapevine asteroid mosaic-associated virus (GAMaV), Grapevine rupestris vein feathering virus (GRVFV), and Grapevine red globe virus (GRGV) [s (GRGV) . The pats (GRGV) ,15.Since fighting against viral phytopathogens is difficult and the ways to completely destroy viruses directly in the vineyard are unknown, it is necessary to use healthy planting material tested for viruses at the stage of seedling production in nurseries .Early detection of foci of viral infection of grapevines allows to prevent their large-scale spreading and take measures to reduce the economic damage to the industry . In RussThe aim of this work was to study the distribution and genetic diversity of grapevine viruses in Russia. Among them, we selected 7 pathogens that have the most significant economic effect and carried out a large-scale phytosanitary study of grapevine plantations in three southern regions of Russia. Five viruses we previously detected were included to understand how widespread they are, as well as GFLV and GFkV, which are usually included in the monitoring of vineyards for viruses.During the studies, we carried out phytosanitary monitoring of 335 grape plantations in various agricultural landscapes, including commercial, small farms, and abandoned plantations. In total, we examined grape plantations of 83 cultivars and hybrids, as well as a number of unspecified cultivars.An analysis of the infection symptoms in the plants of the surveyed territories revealed that over 56% of the samples collected in the Crimea had various types of chlorotic leaf yellowing and spots, which may be a manifestation of infection with various viruses and viroids. The second most common symptom (about 17%) was reddening of the interveinal areas of the leaf blade with main veins remaining green . Often wDiagnostics of collected samples for the presence of 7 grapevine viruses showed that in the Crimea 610 plants (49.5%) were infected with at least one of the viruses under study, in the Krasnodar region—295 plants (49.8%) and in the Stavropol region—18 plants (54.5%) .In the Krasnodar region and Crimea, we detected all viruses under study, in the Stavropol region—5 out of 7 (GFLV and GFkV were not detected) . This reIn the Stavropol region, GLRaV-1 was more widespread; it was identified in 33% of the collected samples, while GLRaV-2 and GLRaV-3 were detected in 6% of the plants. This was the highest percentage of GLRaV-2 infections in all surveyed areas. The highest percentage of GLRaV-3 was observed in the Republic of Crimea, where it was found in 10% of the samples. In general, leafroll viruses were less prevalent than viruses belonging to the stem pitting complex.GRSPaV associated with grapevine rupestris stem pitting disease was identified in 15% of the samples in the Crimea, in 10% of the plants in the Krasnodar region, and in 6% of the samples in the Stavropol region. GVA was more prevalent in the Stavropol region and the Republic of Crimea, where it was detected in 12% of the plants, while in the Krasnodar region the virus was detected only in 4% of the tested samples.Some of the plants were infected with two or more viruses at the same time . In the Since phylogenetic reconstruction can be affected by recombination , a recomAccording to phylogenetic analysis of the coat protein gene, GVA isolates are usually classified into 4 groups . AlignmeIn recent decades, a large number of studies on the genetic diversity of GRSPaV have been carried out, which made it possible to identify several molecular groups of GRSPaV ,24,25,26A BLASTn analysis for a fragment of the GFkV coat protein gene showed that the identity of the nucleotide sequences of the five Russian isolates with isolates from the GenBank database varied from 88.38% to 100% ; the cloA comparison of fragments of the GFLV coat protein gene using BLASTn demonstrated that the sequences of the Russian isolates are 86.77–90.12% identical with the sequences of the GFLV coat protein gene available in the GenBank. According to previous studies in the field of GLRaV-1 phylogeny, all isolates belong to 3 groups . We analCurrently, 6 phylogenetic groups of GLRaV-3 are distinguished . In our According to previous studies, there are 5  or 6 molFour GLRaV-2 isolates from commercial grape cultivars Cabernet Sauvignon and Muscat Golodrigi in the Crimea, as well as from table grape cultivars Libya and Moldova in the Krasnodar region and Stavropol region, respectively, belonged to the H4 group. Two isolates found in the vineyards of the Cabernet Sauvignon cultivar and an unknown grape cultivar in the Yalta district of the Republic of Crimea belonged to the PN group. A BLASTn analysis showed the identity of our isolates with isolates from the GenBank at the level of 88.63–99.66%.An RFLP analysis of two amplicons of the coat protein gene produced different restriction profiles that are presented in Previously, we have determined that the isolate 3 belongs to group 3 of GLRaV-2 (GenBank ID MH074870) by digestion of PCR product amplified with primers V2dCPf2/V2dCPrl . In thisTaqI restriction profile of the V2dCPf2/V2dCPrl amplicon corresponds to the profile of groups 3 and 4, while the RsaI restriction profile—to the profile of the RG group isolates. The data obtained made it possible to suggest the presence of an isolate of a new group in the analyzed sample or the presence of a mixed infection of isolates belonging to several groups of GLRaV-2. At the same time, phylogenetic analysis shows that isolate 346 belongs to the H4 group which is separate from the RG isolates.As a result of digestion of two fragments of the GLRaV-2 coat protein gene of isolate 346, we obtained restriction profiles which on the whole did not correspond to any of the previously described groups. For instance, the restriction profile of the GLR2CP1/GLR2CP2 amplicon was the same as the profile of the group 3 isolates. The RsaI and TaqI.PCR with primers V2dCPf2/V2dCPrl did not result in amplification of a fragment of the coat protein gene of isolate 1853 collected from grapevine samples in the Stavropol region. Therefore, we were not able to identify the exact RFLP group by the digestion of two PCR products with the enzymes Here we describe the results of a large-scale study of the distribution of 7 economically significant grapevine viruses conducted in the southern regions of Russia. For the first time in Russia, we have earlier detected a number of grapevine viruses in individual vineyards of the Crimea and Krasnodar region ,18,19,20Grapevine Pinot gris virus (GPGV), Arabis mosaic virus (ArMV), Grapevine virus B (GVB), Grapevine red blotch-associated virus (GRBaV), etc.The diversity of symptoms of viral diseases that we observed in the process of phytosanitary examination of grapevine plantations is likely to be associated with the difference in action of the same species of viruses on different cultivars and hybrids of grapes. In addition, the size of the territory and the location of vineyards in different zones that we studied indicate the influence of climatic conditions on the symptoms. Infection of the grapevine with several viruses as well as infection with other phytopathogens  can result in unique symptoms and an increase in their manifestation ,30,31. FIn this work, we expanded the species composition of viruses for the first time detected in the Krasnodar region; such are GVA, GRSPaV, GLRaV-1, GLRaV-3, GFLV and GFkV. In the Stavropol region, we for the first time detected GVA, GRSPaV, GLRaV-1, GLRaV-2, and GLRaV-3. In the Crimea, we showed the distribution of 7 grapevine viruses: GVA, GRSPaV, GLRaV-1, GLRaV-2, GLRaV-3, GFLV and GFkV.The data obtained on the prevalence of GRSPaV  indicate its ubiquitous presence in the vineyards of Russia. A phylogenetic analysis showed that most of the studied isolates belong to the BS group and one isolate belongs to the SG1 molecular group. Such clustering did not depend on the geographical location of the plants from which the samples were collected. The SG1 and BS groups and the GRSPaV-1 group have previously been described in Brazil . IsolateThe prevalence of GVA varied from 4% in the Krasnodar region to 12% in the vineyards of the Crimea and Stavropol region. Phylogenetic typing confirmed the prevalence of molecular group IV in the vineyards of southern Russia, whereas group I was less prevalent. For comparison, the absolute majority of isolates in Tunisia (70%) belonged to group I, while group IV was the second most prevalent . The preIn this work, we studied the distribution of three main pathogens of grapevine leafroll disease: GLRaV-1, GLRaV-2, and GLRaV-3. In general, from 2 to about 10% of the analyzed samples were infected with one or more leafroll viruses at the same time. The data on the distribution of these viruses obtained in this study are in line with the results of our previous studies in the Crimea, when out of 689 samples, 4.9% were found to be infected with GLRaV-1 and 5.4%—with GLRaV-3 .As a result of the study of evolutionary relationships, Russian GLRaV-1 isolates were found to belong to molecular group III. A similar situation was observed in Slovakia, where most of the samples belonged to group III, while several isolates belonged to molecular group I . IsolateVitis vinifera allowed to identify GLRaV-2 in about 15% of the samples collected in the Krasnodar region [Our earlier studies of five table cultivars of r region . As a rer region .GLRaV-3 is the predominant species in the vineyards of the Crimea, regardless of the cultivar and age of the grapevine, while GLRaV-1 is predominant in the Stavropol region and Krasnodar region. The overall infection level of GLRaV-3 in the Crimea was about 10%, which is higher than in our previous studies on a smaller selection of samples . The GLROur studies showed that GFkV is widespread almost everywhere; it was identified in 27% of the grape samples collected in the Crimea and in 36% of the samples from the Krasnodar region. The virus has not yet been detected in the Stavropol region. Our results indicating a widespread infection of grapevines with GFkV are supported by data obtained by colleagues from other countries . In CanaGFLV is considered one of the most widespread nepoviruses in the world . In our Hop stunt viroid, Grapevine yellow speckle viroid 1 and -2), improving detection methods are an integral part of the further development of viticulture in Russia.The results of phytosanitary monitoring show a wide distribution of viruses in the vineyards of Russia and emphasize the urgent need for a comprehensive approach in the fight against the spread of viral infections. This requires the development and implementation of certification programs for planting material produced in Russia, as well as the control of imported planting material for the presence of key viruses. Creation of nurseries for healthy planting material and implementation of agrotechnical and carrier control measures will make it possible to limit the spread of harmful viruses in Russia. Regular phytosanitary monitoring of main viticulture zones of the south of Russia, including new regions and vineyards, expanding the list of harmful viruses by including recently discovered ones  and commonly known  and viroids , as well as the Stavropol region, where the sum of active temperatures is insufficient for growing grapes without sheltering them for the winter.At selected vineyards, symptomatic samples presumably infected with viruses were collected. Taking into account that the symptoms of infection and the intensity of their manifestation can vary depending on the cultivar, climatic conditions, pathogen titer in the plant, and coinfection with one or several other viruses, we collected samples with any visual deviations from healthy plants.Samples of grapevines and leaves were collected from various layers, stored in a refrigerator at +4 °C, and transported to the laboratory for analysis. In the laboratory, samples were stored at −20 °C.Total RNA was extracted from 0.3 g of the combined sample which included fragments of grapevines and leaves, according to a slight modified method described in . RNA quaFor each sample, a control amplification of 18S rRNA was performed with the primers listed in Taq Buffer with (NH4)2SO4, 0.2 mM each dNTP, 1 μM each primer, 2.5 mM MgCl2, 0.375 U Taq polymerase . The primers used for detection are listed in Viral detection was conducted by PCR using 1 μL of cDNA as a template in a reaction mixture containing The PCR amplification consisted of an initial denaturation at 94 °C for 3 min, followed by 35 cycles of 94 °C for 45 s, 56 °C for 45 s, 72 °C for 1 min. The final elongation stage was carried out at 72 °C for 7 min. The resulting PCR products were separated in 1% agarose gel and the corresponding bands were excised. DNA was purified using a Cleanup Standard Kit for DNA purification from agarose gel according to the manufacturer’s protocol . A virus detected in a single vine was considered as a single isolate. To confirm the presence of virus, the obtained amplicons were sequenced by the Sanger method with forward and reverse primers using Big Dye Terminator v.3.1 chemistry reagents on an ABI PRIZM 3730 automatic sequencer according to the manufacturer’s instructions. The complete sequence was assembled using the BioEdit Sequence Alignment Editor v.7.2.0 software. Then, using the BLASTn algorithm, we compared the sequences that we obtained with those available in the NCBI database. The obtained sequences were deposited in the GenBank, access numbers are listed in Positive DNA samples were used for sequencing the gene encoding the coat protein and studying the phylogeny of GRSPaV, GVA, GLRaV-1, GLRaV-2, GLRaV-3, GFLV, and GFkV. The list of isolates used for phylogenetic studies is presented in Multiple alignment was performed using ClustalW in the BioEdit Sequence Alignment Editor v.7.2.0 program. Phylogenetic analysis was performed in the MegaX program using the maximum likelihood algorithm ,56. The RsaI and TaqI using tools of the Clone Manager 6N program. The second pair of primers GLR2CP1/GLR2CP2 was used for more specific detection of the molecular group GLRaV-2RG; comparison of the obtained isolate profiles with those published earlier [For detection of the GLRaV-2 group, we also used RFLP . PCR pro earlier  helped up ≤ 0.05 were considered significant.To search for recombination sites in the genomes of the isolates that we found, we used nucleotide sequences of amplified coat protein genes of viruses GVA, GRSPaV, GLRaV-1, GLRaV-2, GLRaV-3, GFLV, and GFkV, as well as nucleotide sequences of coat protein genes of all viruses submitted to GenBank as of March 2021 . The sea


The present paper focuses on laboratory tests of fatigue strength of prototype under ballast mats (UBMs), carried out according to the procedure described in the new European standard EN 17282, which was released in October 2020. The mineral wool-based mat revealed significant differences in the values of static and dynamic characteristics, measured before and after the fatigue tests. The elastomeric mats based on recycled materials (SBR granulate and fibers) turned out to have had sufficient durability and effectiveness of protection against vibration caused by railway traffic. The values of static and dynamic bedding moduli, determined before and after the fatigue tests, were used to develop a viscoelastic rheological model of the vibration isolator with the use of fractional derivatives. Using this original model of the ballasted track system with four degrees of freedom, a significant influence of cyclic loading on the level of vibration suppression (insertion loss factor) was demonstrated. The analytical model confirmed that the mats with variations of bedding moduli exceeding 10% should not be used as resilient elements. Under ballast mats (UBMs) have been used since the 1960s [An effort has been made to find efficient solutions that would enhance the effectiveness of vibration isolation of various resilient elements applied in track systems. One of the solutions proposed in the literature is the application of rubber-based mats. Rubber-based mats have a wide range of applications as a common vibration isolation material in various track systems. They can improve the deformation behaviors of both ballasted and ballastless track systems. Zheng et al.  analyzedThe rubber can be used to manufacture resilient elements such as UBMs and other vibration-isolating mats, but it can also be applied as a material of the sleepers . Zeng etThere are many possible methods for analyzing and assessing the vibration isolation function of UBMs and other resilient elements. Wettschureck et al.  proposedAn interesting approach was discussed in , where ZBased on the performed literature study, it can be stated that UBMs are elements with a wide range of possible applications, which are worth a more thorough analysis. However, the research presented in the literature is not comprehensive and needs to be extended, especially in the light of new standardization and the lack of sufficient data on fatigue strength analysis.There are many methods that can be used for improving the fatigue properties of various materials. Panin et al.  studied The main aim of this paper is the analysis of the influence of fatigue strength of prototype UBMs on the effectiveness of protection against vibration caused by railway traffic. The authors present novel results obtained in the fatigue tests that were conducted according to the requirements of the newly released (October 2020) standard EN 17282  for undeResults obtained in laboratory fatigue tests were used in the rheological model of the ballasted track structure with a UBM. The original 4DoF model was presented in the previously published works of the authors . Using tFatigue test on a UBM in a steel box filled with ballast;Fatigue test on a UBM with a geometric ballast plate (GBP) (for UBMs used as vibration isolators);Test of resistance to severe environmental conditions, such as water, high temperatures and freeze–thaw resistance.According to the newly released standard EN 17282 [Fatigue strength and resistance to severe environmental conditions of vibration isolators are very important factors that affect the durability of the railway track structure and the effectiveness of vibration isolation. The durability of UBMs can be assessed by testing their mechanical fatigue strength and the influence of long-term dynamic loads on the variability of certain parameters. The test consists of applying a dynamic load to the UBM sample, which simulates service loads in laboratory conditions.The fatigue test on a UBM in a ballast box, according to EN 17282  requiredIn the fatigue test with GBP, according to EN 17282 [Assessment of the durability of UBMs—evaluated based on their fatigue strength—is important from the point of view of the isolation effectiveness (isolating properties of UBMs). In the ballasted track structure, a replacement of UBMs would result in a major repair of the track structure, that is, removal and reconstruction of all the structural elements . Therefore, durability is crucial for infrastructure managers, who cannot allow themselves to use UBMs with durability that is lower than the durability of other structural elements.Selection of a UBM during the design process has to include its fatigue strength. Even if other properties of the mat are satisfactory, neglecting the durability parameter may lead to a fast increase of the bedding moduli under service loads, which may affect one of its main functions—the required effectiveness of vibration isolation.The geometric ballast plate (GBP) that was used in the fatigue tests of UBMs was manufactured at the Warsaw University of Technology, in accordance with the requirements of EN 17282 ). The suIn order to manufacture the geometric ballast plate, a vector 3D model in the Creo Parametrics 2.0  environment was prepared, which was afterward imported to the Mastercam X5  software . Then, aThe plate was made of steel 304L, which is an austenitic nickel-chrome steel with good resistance to corrosion . The dimThe authors reviewed the requirements of foreign railway infrastructure managers and prepared a tabular comparison of the limiting values for the parameters that are particularly important from the point of view of the proper selection of UBMs, with regard to their durability . In the No perforations, cracks, visible damage during and after the test;Cstat ≤ 10%;Variation of the static bedding modulus ΔCdyn ≤ 10%.Variation of the dynamic bedding modulus ΔBased on the gathered data and the requirements of EN 17282 [38.4—mineral wool sample, thickness 35 mm;3;45.4—styrene-butadiene rubber (SBR) sample, thickness 20 mm, density 500 kg/m3;49.4—styrene-butadiene rubber (SBR) sample, thickness 20 mm, density 600 kg/m3.53.4—styrene-butadiene rubber (SBR) sample, thickness 20 mm, density 700 kg/mFatigue tests were performed on four samples of UBMs :38.4—miThe samples had dimensions of 300 mm × 300 mm. The material used for rubber-based mats can be classified as an elastomer. This type of material does not lose its structural continuity when submitted to tension or compression; it can undergo large deformations and regains its initial shape after removal of the load. The mineral wool, on the other hand, cannot be classified as an elastomer.Mineral wool mats have already been applied in some ballastless and ballasted track structures, mainly in Sweden, Norway and Denmark. The authors have decided to investigate the prototype UBMs based on mineral wool in the same conditions as SBR-based mats in order to compare their fatigue properties and durability.The tests were carried out according to EN 17282 [According to EN 17282 [Cstat and Ctend;Static bedding moduli: Cdyn at frequencies 1, 2, 3, 5, 10, 15 and 20 Hz, using the load-controlled method, with the load range 1.8 kN to 9.0 kN;Dynamic bedding modulus CH at frequencies 8, 10, 12.5, 16, 20 and 24 Hz, using the displacement-controlled method, with the initial static load of 9.0 kN.Dynamic bedding modulus The same values were determined again after 1 to 2 weeks after the fatigue test. Definitions of static and dynamic bedding moduli, together with the detailed descriptions of the tests, can be found in previous works of the authors ,29.Fmin = 1.8 kN to Ftest = 9.0 kN, after which the parameters defined above were determined once again using both the load- and displacement-controlled methods. The static and dynamic (at 5 Hz) bedding moduli were tested further every 125,000 load cycles, that is, after 125,000, 250,000 and 375,000 load cycles.In the next step, the samples were submitted to 500,000 load cycles with the value from After the tests, a visual inspection of the samples was performed, which was aimed at finding potential damage arisen during the tests, such as perforation, cracking or other damage. If any damage was found, the samples were qualified as not fulfilling the requirements for the fatigue strength and rejected.Variations of the determined values of bedding moduli were calculated using the following formulas:2,2, measured after the test,2, measured before the test,2,2, measured after the test,2, measured before the test,The test stand consisted of a universal testing machine INSTRON 8802  with twoCstat and Ctend) and dynamic (Cdyn5) bedding moduli at 5 Hz, during and after the fatigue tests performed on four UBM samples. It can be noticed that for UBM 38.4 the values of all determined parameters decreased with the applied load cycles and after two weeks from the test, which means that the material stiffened. It points to a high material heterogeneity of mineral wool and possible damage of the material macrostructure caused by the cyclic dynamic loading. In the case of rubber-based samples, UBM 45.4, 49.4 and 53.4, the values of all tested parameters increased during the test, reached maximum after 500,000 load cycles and decreased two weeks after the test. It indicates the dynamic stiffening effect that is characteristic of elastomers. The bedding moduli grow during the test, and the elastic recovery of the samples can be observed after the test.After the fatigue tests , all samples were submitted to visual inspection with an unaided eye, according to EN 17282 Annex E: “After the end of fatigue test and the end of bedding modulus test, the UBM shall be visually inspected in order to look for evidence of damage ” [The chipping and changes in the material macrostructure were visible already in the first series of 100,000 load cycles. In rubber-based samples UBM 45.4, 49.4 and 53.4, no damage was identified. Additionally, going behind the requirements of EN 17282 [CH) tests at the frequency of 20 Hz, using the displacement-controlled method. Red lines correspond to the values determined before the fatigue test (designated as “0”), green—values determined after 500,000 load cycles (designated as “500”) and blue—values determined two weeks after the fatigue test (designated as “500_post”). Mineral wool sample UBM 38.4 did not exhibit a sufficient fatigue strength in the tests aimed at the preselection of the mats because the variations of static and dynamic bedding moduli exceeded the limiting value of 10% . A possible reason may be the fact that the material macrostructure of the sample was damaged, which caused the decrease of tested parameters and the sample degradation after the application of cyclic loading;During the fatigue tests of rubber-based UBM samples, a significant dynamic stiffening effect was identified. The values of dynamic bedding modulus increased and the samples did not undergo a full relaxation between successive load cycles;Rubber-based samples UBM 45.4, 49.4 and 53.4 exhibited sufficient fatigue strength and therefore were selected for further tests. There was no visible damage on the surfaces of these samples after the tests, no material chipping, perforations or cracking. A slight decrease in the values of tested parameters (≤10%) is acceptable and may have resulted from some fine damage of the samples’ macrostructure. The samples were made of SBR granulate and fibers glued with a polyurethane adhesive. During the fatigue test, the connection between the granulate and fibers may have been damaged, which resulted in a small decrease in the measured parameters;Cstat decreased by 20.0%, Cdyn5 decreased by 10.7% and CH increased by 9.8 ÷ 15.1%—depending on the load frequency. The obtained results—especially large variations of the bedding moduli determined before and after the tests—point to significant heterogeneity of the material, which means that the mat is not suitable for the assumed application;In the case of mineral wool-based UBM 38.4, the value of Cstat decreased by 6.3%, Cdyn5 decreased by 6.4% and CH decreased by 4.9 ÷ 8.4%—depending on the load frequency. The obtained results point to homogeneity of the material;In the case of rubber-based UBM 49.4, the value of The material of the mat has a significant influence on its fatigue strength—elastomeric materials that are produced from the recycled old tires (based on SBR granulate and fibers) exhibit satisfactory characteristics and are suitable for the assumed application.Performed tests allowed the authors to formulate the following conclusions:In order to describe rheological properties of UBMs, the Fractional Zener (FZ) model was used see . The modivatives . It can The following definition of the fractional derivative of the order tion (4) :(5)Dαz(tApplying Laplace transforms to Equation (4) leads to the following equations:The complex stiffness modulus The complex stiffness modulus constitutes the amplitude of the harmonic steady-state force response The authors decided to present the results of the analytical analysis only for the mineral wool-based mat UBM 38.4, which exhibited the lowest fatigue strength in the experimental tests. In the case of this mat, the variations of the static and dynamic parameters determined in the laboratory exceeded the limiting values of 10% that were recommended by the authors in Parameters of the FZ model that were obtained in this analysis were used in the 4DoF model, which describes the behavior of the ballasted track structure. The original 4DoF model was presented in the previously published works of the authors . Using tAnalysis of the mechanical model of the structure indicated that the low fatigue strength of the UBM, measured as a variation of the static and dynamic bedding modulus, results in a significant decrease in the effectiveness of vibration isolation. Analytical results confirm that the mineral wool-based mat UBM 38.4 is not suitable for the assumed application and should be rejected at this stage of the tests.The current work focused on the analysis of the influence of fatigue strength of prototype under ballast mats (UBMs) on the effectiveness of protection against vibration caused by railway traffic. The authors presented novel results obtained in the fatigue tests that were performed in accordance with the requirements of the new standard EN 17282 [The prototype mineral wool sample did not exhibit a sufficient fatigue strength, as the variations of static and dynamic bedding moduli exceeded the limiting value of 10%. The obtained results point to significant heterogeneity of the material, which means that the mat is not suitable for the assumed application as a vibration isolator. Rubber-based samples exhibited sufficient fatigue strength and therefore were indicated for further tests. There was no visible damage on the surfaces of these samples after the tests, no material chipping, perforations or cracking.The mineral wool-based mat was then analyzed analytically using a 4DoF rheological model of the ballasted track structure with a UBM, developed by the authors. Results obtained from the mechanical model of the structure prove that the low fatigue strength of the UBM, determined as a variation of the static and dynamic bedding modulus, resulted in a significant decrease in the effectiveness of vibration isolation. An analytical model confirmed that the prototype mineral wool-based UBM, with its variations of the static bedding modulus at the level of 20% and the dynamic bedding modulus exceeding 10%, should not be used as a resilient element aimed at isolation of the vibrations caused by railway traffic.


The effect of small additions (1–5 wt.%) of tetraphenylporphyrin (TPP) and its complexes with Fe (III) and Sn (IV) on the structure and properties of ultrathin fibers based on poly(3-hydroxybutyrate) (PHB) has been studied. A comprehensive study of biopolymer compositions included X-ray diffraction (XRD), differential scanning calorimetry (DSC), spin probe electron paramagnetic resonance method (EPR), and scanning electron microscopy (SEM). It was demonstrated that the addition of these dopants to the PHB fibers modifies their morphology, crystallinity and segmental dynamics in the amorphous regions. The annealing at 140 °C affects crystallinity and molecular mobility in the amorphous regions of the fibers, however the observed changes exhibit multidirectional behavior, depending on the type of porphyrin and its concentration in the fiber. Fibers exposure to an aqueous medium at 70 °C causes a nonlinear change in the enthalpy of melting and challenging nature of a change of the molecular dynamics. The widespread employment of nanotechnology in modern medicine, the transition from traditional macro- and micro- to submicron and nanoscale medication forms (MF), as well as the implementation of ultrafine implants and diagnostic systems, cause the scientific community to pay close attention to bio-based polymer materials that are completely decomposed in the living systems without the formation of toxic products. Poly(3-hydroxybutyrate) (PHB) as a basic representative of polyhydroxyalkanoates’ family (PHA) is such bacterial biodegradable and biocompatible polymer with great commercial perspectives and high sustainability ,2,3. PHBThe crucial characteristics of the biodegradable MF are the kinetic parameters of drug release in vitro or in vivo which are determined by the combination of drug diffusion and biopolymer decomposition rate in the limited space of fibrous micro- nanocarrier. Since the drug diffusional transport depends strongly on the inherent structure of the biopolymer, its morphology and crystallinity, all of these characteristics can significantly affect the kinetic profile of drug release, and, eventually, the effectiveness of the MF implementation. Structural changes in fibrillar mats during storage and can be caused by multiple factors, such as water absorption, heating, oxidation, ozonolysis, action of UV radiation, as well as the degradation effect of microorganisms. The listed factors can act simultaneously or consequently, depending on the operating conditions of the MF and the environment.2 and silicon nanoparticles [The effective method of direct impact on the structure of polymer materials is to dope it with the modifiers of organic and inorganic natures. In our preliminary reports, we demonstrated the influence of a series of additives on the structure of PHB-based fibrous materials. As the modifiers we used dipyridamole , chitosaarticles , Fe-chloarticles , Zn-porparticles , Mg-chloarticles , etc., tThe challenges related to the variation of free volume ,14 and sOf particular interest is the incorporation of porphyrin metal complexes as the special dopants into the PHB polymer. It is well known from the numerous literature papers that the complexes of metals with TPPs have unique photocatalytic and antimicrobial properties ,19. MetaAlong with the bactericide activity, due to the specific geometry and electronic structure, the complexes of metals with porphyrins have a significant effect on the crystallization and segmental orientation of macromolecules . The pri2-TPP) and Fe(III) (FeCl-TPP) are the most promising PHB dopants for creating polymeric materials for medical use. Sn-porphyrin metal-complexes are currently employed in the design of photocatalysts that promote the destruction of organic toxicants [2-TPP to aggregate in comparison with the complexes of porphyrins and metals in the oxidation states +2 and +3. FeCl-TPP molecules could have a strong interaction with PHB macromolecules; however, the presence of only one Cl as a ligand on only one side of the cycle leads to the potential ability of molecular aggregation.Complexes of TPP with Sn(IV)  and Fe (III) on the structural and dynamic parameters of a fibrous material based on PHB, as well as the detection of external factors’ impacts  on the structural and dynamic characteristics of the studied biodegradable polymer-porphyrin compositions.ν) 2.06 × 105 D, density ρ = 1.248 g/cm3, melting point Tm = 177 °C, initial degree of crystallinity ~63%.For ES we used microbiologically synthesized PHB Series 16F Biomer  with a viscosity-average molecular mass (M3-TPP complex and SnCl2-TPP complex were obtained according to the procedure described earlier [3), but insoluble in water. To obtain the solution prepared for ES formation, the porphyrin dopants were dissolved in CHCl3 and then added to solutions of PHB in CHCl3. Thus, the both components have the same cosolvent.TPP, FeCl earlier ,32. Thei3-TPP, and PHB/SnCl2-TPP in CHCl3 were prepared at a temperature of 60 °C by stirring on an automatic magnetic stirrer to complete uniformity. The concentration of PHB in the solution was 7 wt.%, the content of TPP, FeCl3-TPP, SnCl2-TPP was equal to 1, 3, and 5 wt.% relatively to the mass of PHB.The ES-formation solutions of PHB, PHB/TPP, PHB/FeClFibers were obtained by ES on a single capillary laboratory setup with the following parameters: capillary diameter—0.1 mm, voltage—12 kV, distance between electrodes—18 cm, solution conductivity—10 μS/cm as described in  The fibe−2 torr. The signal accumulation time was varied in the range 600–5000 s.X-ray structural analysis (XRD) of the samples was carried out by transmission recording. High-resolution two-dimensional scattering patterns were obtained using the S3-Micropix small- and wide-angle X-ray scattering system  ). A Pilatus 100K ) detector was used, as well as a PSD 50M linear devise for the argon flow, a high voltage of 50 kV and a current of 1 mA on the Xenocs Genix ) source tube. Fox 3D X-ray optics ) were used to form the X-ray beam; the diameters of the forming slits in the collimator were 0.1 and 0.2 mm. To eliminate X-ray scattering in air, the X-ray mirror unit and the camera during signal accumulation were placed under the vacuum of (2–3) × 104 with a radical concentration of around 1 × 10−3 mol/L.X-band electron paramagnetic resonance (EPR) spectra were recorded on an EPR-V automatic spectrometer . To avoid saturation effects, the microwave power did not exceed 1 mW. The modulation amplitude was always significantly less than the resonance line width and did not exceed 0.5 G. A stable nitroxide radical TEMPO was used as a spin probe. The radical was incorporated into the fibers from the gas phase at a temperature of 50 °C for an hour. The concentration of the radical in the polymer was determined by double integration of the EPR spectra. As the reference was vacuum degassed TEMPO solution in CCl14N nucleus: gxx = 2.0093, gyy = 2.0063, gzz = 2.0022, Axx = 7.0 G, Ayy = 5.0 G, Azz = 35.0 G. The value of Azz was determined experimentally from the EPR spectrum of TEMPO in PHB recorded at the temperature of liquid nitrogen. The obtained value is close to the value of Azz given in [Simulation of EPR spectra was performed using the computer program described in This program is the modified version of the program described in . The simgiven in .Hydrolysis of samples in aqueous medium was studied at 70 °C ± 1 °C. Before the introduction of the radical, the samples exposed to water were dried in the vacuum oven to constant weight for 100 hr.The differential scanning calorimetry (DSC) study was accomplished on a NETZSCH DSC 204 F1 instrument  in an Ar atmosphere with a heating rate of 10 K/min. The average statistical error in the measurement of thermal effects was ±3%. The enthalpy of melting was calculated using the NETZSCH Proteus program. Thermal analysis was conducted according to the standard procedure . Peak seThe scanning electron microscopy (SEM) to obtain geometric parameters of the fibrous materials was performed by TM-3000 scanning electron microscope ) at an accelerating voltage of 20 kV. Au layer of 10–20 nm was deposited on the surface of a nonwoven fibrous material sample. The computation and measurements of PHB fibrillar diameters were achieved using the software tool Java-based ImageJ version 1.52a  and OriginPro 2018 . The histograms of diameter distribution for the loaded fibers of PHB have been built on the base of statistic estimation for 100 fibrillar elements patterned at SEM microphotographs.The pristine PHB fibers demonstrate the large concentration of ellipsoid structures as the anomalous bead-like fragments existing in the fibrous mats along with conventional cylindrical form being typical for electrospun fibers, see 2-TPP complex content 1–5 wt.%, the ellipsoid elements have completely disappeared; and for 1% of the complex, the fiber diameter distribution has the maximum at 1.75 ± 0.25 μm. The distribution asymmetry  fibers, the changes in the degree of crystallinity and the longitudinal size of crystallites are within the experimental errors. The significant effect of FeCl-TPP on the crystal structure of the polymer is due to strong interaction of the additive molecules with the polymer macromolecules and the formation of dopant particles that can serve as the nuclei of crystallization. It should be noted that with an increase in the FeCl-TPP concentration from 3% to 5%, only a slight decrease in the degree of crystallinity and the longitudinal size of crystallites is observed. It takes place due to the aggregation of complexes into larger particles, which does not lead to a further increase in the proportion of crystallites during ES.2-TPP) fibers at 140 °C leads to an insignificant increment in the degree of crystallinity.Thermal sterilization of polymeric materials remains the most common method in clinical practice. The recommended hot air annealing temperature required for the death of all microorganisms is 160 °C, however, the mode allowed for processing materials based on PHB fibers is limited to 140 °C, which is due to the onset of polymer degradation. The structure of the amorphous regions is largely determined by the degree of crystallinity of the polymer. As a result, the addition of porphyrin metal complexes to the PHB fiber changes not only the degree of PHB crystallinity but also the morphology and molecular dynamics in the amorphous regions. The molecular mobility of the amorphous regions of the polymer was studied by the spin probe technique using the stable nitroxide radical TEMPO. The typical EPR spectra of the radical in the polymer matrixes under consideration are shown in The widely used method for determining the rotational parameters of spin probes in polymers is the computer simulation of the EPR spectra. It was found that for high-quality simulation of the spectra of the studied systems it is necessary to take into account the anisotropy of the rotational mobility of radicals, the continuous  distribution of paramagnetic molecules over the rotational diffusion coefficients, as well as high-frequency low-amplitude vibrations of paramagnetic molecules near the equilibrium position—quasi-vibration ,33,34,436 c−1, while the coefficients of rotational diffusion around Y and Z axes are in the range 107–108 c−1. Such anisotropy may indicate the interaction of probe molecules with functional groups of polymer molecules due to p-orbitals of nitrogen and oxygen atoms. A wide distribution of rotational mobility of the radicals was also revealed. This is caused by inhomogenity of the structure of the amorphous region of the polymers. Indeed, the amorphous phase is a set of structures characterized by different packing densities and different molecular dynamics of polymer chains. The EPR spectrum is a superposition of the spectra of radicals located in different regions of the amorphous phase and, therefore, having different mobility.It was found that in all systems under study, paramagnetic molecules rotate anisotropically. The coefficients of the rotational diffusion of the radicals around X axis of g-tensor (N−O bond) do not exceed 2 × 10−7–10−8 s is a very time-consuming procedure. In addition, the present work is aimed at the qualitative analysis of changes in the radicals’ mobility as a result of treatment of the polymer matrix, and not at the interpretation of the exact values of the rotational parameters. In such a case it is useful to introduce a parameter that qualitatively characterizes the rotational mobility of radicals, can be determined without spectra simulation, and has sufficient sensitivity to small changes in the shape of the spectrum, such as the changes shown in It should be noted that simulation of EPR spectra of low-molecular-weight dopants in polymers in the range of rotational correlation times of 10H+1 is peak-to-peak width of the low-field spectral component; I+1 and I−1 are intensities of the low-field and high-field components correspondently.Here Δ−11 s ≤ τc* ≤ 1 × 10−9 s. In this region, the EPR spectrum consists of three well-resolved components, the width of which is described within the framework of the Redfield theory [c* for the three above systems are shown in This formula was proposed for the determination of the rotational correlation times of the nitroxide radicals of the piperidine series in the case of their isotropic rotation in the range of rotational correlation times of 5 × 10d theory . In our c* is in the PHB/FeCl-TPP system; in the PHB/TPP fibers, the correlation time increases not so significantly. In PHB/SnCl2-TPP fibers, a decrease in τc* is observed, although the degree of crystallinity determined using DSC increases with an increase in the additive content.2-TPP, a decrease in the rotational correlation time of the probe is observed, that is, an increase in the mobility of the polymer chains. This phenomenon is caused by the loosening effect of this metal complex, which is distributed in the system at the molecular level, and, therefore, the number of individual particles per unit volume of the polymer, in this case, is maximal.As shown above, doping of PHB with PHB/FeCl-TPP causes an increase in the polymer crystallinity. This phenomenon is accompanied by increase in the correlation time, and, consequently, a slowdown in the molecular dynamics of macromolecules. In PHB/TPP, the effect of slowing mobility is weak. For the polymer doped with SnCl3-TPP due to the strongest change in the degree of crystallinity in these samples. It is known that impurity molecules do not diffuse into crystal structures; their concentration in dense amorphous regions is insignificant.Of great scientific and practical interest is the study of the effect of sterilization on materials and products for medical use. The choice of optimal conditions for polymer processing, in view of the fact that the aggressive action of temperature, radiation, oxidizer , along with the disinfection of the material and the destruction of pathogenic microorganisms, can lead to a significant deterioration in a structural hierarchy and hence in polymer properties.During ES performance, as a result of cooling and solidification, the polymer structure of ultrathin fibers can be far enough from the state of thermodynamic equilibrium. The imperfection in the crystalline phase and biopolymer morphology is manifested in the insufficient orientation of the segments in the fiber, as well as in an atypically low degree of crystallinity. To facilitate the transition of the polymer structure to equilibrium state the thermal annealing is used. The temperature impact allows intensifying segmental mobility and transferring the system to a more thermodynamically equilibrium state. The enhancing in the crystalline phase and especially additional crystallization occurs with the participation of transient polymer molecules located in intercrystalline area. Therefore, one should expect a change in the dynamics of spin probe that reflects the segmental mobility of PHB molecules in the intercrystalline fields. When comparing the mobility of the probe in the initial and annealed polymer samples contained different dopants, an opportunity appears to determine the effect of the additives on the polymer stability and dynamics of the intercrystalline structure.2-TPP, and FeCl-TPP additives. The observed dependences can be explained as follows. During the fibers’ fabrication, an essential proportion of the transitive macromolecules in transitive conformation are formed, but their segmental mobility is frozen as a result of the fiber jet solidification at room temperature. Annealing at 140 °C enhances macromolecular mobility that after gradual cooling leads to additional crystallization with the growth of crystallite sizes owing to the present of transitive straightened macromolecules. The spin probe molecules cannot penetrate into crystallites; therefore, their rotational mobility reflects the molecular mobility only in amorphous areas and in the areas of transitive macromolecules. After crystallization of the transitive areas the radicals are located predominantly in the amoprhous areas, so their average rotational mobility increases. Indeed, the absorption capacity of the fibers for the probe molecules decreases with an increase in the annealing time. For example, in the initial PHB fibers, the concentration of the radical was 0.75 × 1015 spin/cm3, while after annealing for 90 min, it decreased to 0.53 × 1015 spin/cm3, i.e., decreased 1.4 times. At the same conditions, the concentration of the radical in the PHB/SnCl2-TPP composition decreases 2.1-fold, and in the system PHB/FeCl-TPP—10-fold after annealing the samples with 5% additive for 2 h. The greatest decrease in content of the probe for the system PHB/FeCl-TPP corresponds to the greatest decrease in the rotational correlational time of the radicals.The structure and segmental dynamics of biodegradable materials for biomedicine significantly affect diffusion of drugs loaded into polymers and, consequently, the kinetic profiles of active component release. Since the polymer in the body functionalizes often in the aquatic environment, it is important to identify the changes in its structure and segmental mobility as a result of water action. Even a slight increase in the water content affects the diffusion processes of active agents in a polymer matrix. Previously, we studied the effect of an aqueous medium on the structure of PHB ,50,51,52(1)In accordance with the above description, heating the samples in water medium causes an increase in the degree of crystallinity and compaction of amorphous structures;(2)Water molecules penetrating into the polymer matrix produce a plasticizing effect, as a result of which the degree of crystallinity also increases;(3)When water molecules interact with PHB molecules and TPP or metalloporphyrin complexes, the hydrated complexes are formed, which loosen the structure of amorphous regions. After removal of boundless water, hydrated complexes could remain in the fiber;(4)Water molecules penetrate into the accessible surfaces of crystallites and linear structures of amorphous areas, destroying these structures, as a result of which the degree of crystallinity decreases.The exposure of fibrous materials to water medium in the present work was performed at 70° because at room temperature the saturation of polymer volume with water could last several days. When kept in water at 70 °C, the following processes occur simultaneously in the polymer:2 (curves in The EPR probe was introduced into the fibers after their heating in an aqueous medium and subsequent drying in vacuum during 2 days until constant weight. The test results are shown in 2-TPP dopant (curves 1–4) at all times of annealing, there are clearly observed the extreme dependences of ΔH on wt.%. After the minimum point at 1 wt.%, the further growth in the enthalpies is observed that means the increasing of the crystallinity of the polymer and is in good agreement with time correlation dependence in To compare the dopants impact on PHB structure the enthalpies of melting for crystalline fraction of PHB after water treatment are presented in In general, the results obtained indicate that the doping of PHB with TPP and its metallo-complexes has a significant and often multidirectional effect on structural changes in the polymer during its processing for the purpose of sterilization. This observation opens up the possibility of manufacturing materials from PHB with predetermined properties.Generally, it can be concluded that doping of PHB with TPP and complexes TPP with Sn(IV) and Fe(III) leads to significant change in the geometry and morphology of the polymer fibers fabricated using ES method. According to the dynamic and structural exploring the annealing of ultrathin PHB fibers as well as their exposure in aqueous medium strongly affects the structure of the amorphous and crystalline regions of the polymer, moreover, the changing of the structure depends on the nature and amount of the additives. The data obtained should be taken into account when developing a sterilization regime for medical devices made of PHB.


This investigation analyses the influence of the depth and the distance between studs on the fire resistance of lightweight timber-framed (LTF) walls lined with gypsum plasterboards. The simplified model used to determine the fire resistance in Eurocode EN 1995-1-2 provides very conservative values, as few parameters are considered. The new generation of Eurocode EN 1995-1-2 includes an upgrade of the simplified model, allowing us to predict the fire resistance of LTF wall assemblies more accurately. This separating function method considers the number, the thickness and the material of the protection layers, but does not explicitly consider the variation of the depth and the distance between the studs for the calculation of the insulation time of the assembly, besides including some limitations for both parameters. To demonstrate the influence of these parameters, 36 numerical simulations were carried out using the finite element method previously validated with experimental tests. The results obtained from the parametric analyses confirmed that such parameters affect the fire resistance of the LTF wall assemblies in a significant way. In addition, the results revealed an important contribution in the study of LTF wall assemblies against fire resistance, demonstrating the need for including extra geometric parameters in the simplified model in order to increase the accuracy of current models. Lightweight timber-framed (LTF) walls are commonly used in residential buildings due to their light weight and low construction costs. LTF walls are made with solid wood members (studs and tracks) used on buildings, for load-bearing and partition walls. The cladding for internal walls may be developed by gypsum panels (layers). The number of protection layers and insulation materials used in the cavities of the wall depends on the thermal and acoustic efficiency required to the LTF structures at room temperature, but also depends on the required fire rating of LTF walls. During recent years, several experimental tests have been carried out on LFF walls, which can be used for validation.In 1996, Thomas  developeThe separating function method is based on the Component Additive Method, firstly developed in 2009 by Schleifer . The totIn 2010, based on physical models and numerical simulations for heat transfer through separating multiple layered constructions, Frangi et al.  also preAccording to Michael Rauch et al. in 2018 , the sepIn 2016, Xu et al.  developeIn 2020, Piloto and Fonseca  developeH) and (ii) the variation in the stud spacing between centres (OC) affect the fire resistance of LTF walls’ insulation. In addition, this investigation determines the behaviour of the noncharred area of the studs, depending on H and depending on OC dimensions (This investigation addresses how (i) the variation in the depth of the studs , integrity (E) and insulation (I) must be verified, while the (E) and (I) criteria may be applied to non-load-bearing walls . FurtherThis investigation extends the contribution provided by Piloto and Fonseca  on the f2K is considered, using the standard ISO 834 curve as the bulk temperature. On the unexposed side, the simplified version for the boundary condition includes the radiation effect, using only the convection coefficient αc = 9 W/m2K  the exposed side and (ii) the unexposed side are those of Eurocode EN 1991-1-2 . On the  9 W/m2K  14]. An. An2K is−6 W. The 2D heat conduction inside the physical domain is mathematically modelled by the energy conservation equation (Equation (1)), where T represents the temperature [°C], ρ(T) is the specific mass [kg/m3], Cp(T) is the specific heat [J/kgK], λ(T) is the thermal conductivity [W/mK], t is the time [s] and ∇ =  is the gradient. Equation (1) is based on the heat-flow balance for the infinitesimal material volume in each spatial direction.The finite element method is used to solve the nonlinear transient thermal analysis, considering the nonlinear behaviour of the thermal properties and an incremental solution process based on a variable time step (1 to 60 s). The nonlinear convergence criterion is based on the heat flow, considering a tolerance value of 0.001 and a reference value of 10Equation (1) is time-dependent because the heat flux on the boundary exposed to the fire change with time, i.e., the thermal state of the LTF is transient. The solution of Equation (1) is required to determine the temperature inside the physical domain over time, and consequently, to determine the fire char layer near the position of the 300 °C isothermal to define the moving of the pyrolysis process expected in wood.nT˙ is the nodal vector for temperature at the time instant tn, The general procedure of the finite element method for solving Equation (1) is based on the weak-form Galerkin model and from the minimum condition for the weighted residual method, leading to the matrix format of the energy equation (Equation (2)): PLANE55 and SURF151. The SURF151 finite element provides the possibility to model the radiation in the cavity without considering the thermal degradation of the exposed gypsum layer. The mesh size has been determined by a convergence test of the solution. The number of elements increases with the distance OC, H and the thickness of gypsum layer (TG). The numerical model has been validated using the temperature in several points from experimental results provided by Takeda and Mehaffey  + 12.5 × 1 + 400 case and the noncharred area of the central stud after 50 min of fire exposure are shown in On the other hand, H) changes the fire resistance time of the LTF wall assembly insulation (I) of up to 11 min with respect to the separating function method. As the value of H increases, the area of the stud and of the cavity increases, resulting in a higher value of fire resistance of the insulation. The noncharred area  depends on the variation of H. The residual stud area can vary from 1% to 38% for the most unfavourable cases.From OC), with the numerical results (i) being higher than the ones obtained with the separating function method for low space distance and (ii) smaller for higher distances (OC = 600 mm). The variation of the OC can make a difference in the fire-resistance time of the LTF wall of up to 16 min when compared to the separating function method. An increase of 100 mm on the OC distance between studs may reduce the fire resistance of the LTF wall by 5 min, especially when considering a variation from 200 to 300 mm. This reduction will decrease by 2.5 min for larger spacings. It should be noted that the commonly used distances of OC are 400 and 600 mm, therefore, the difference between both methods is smaller in these cases. Despite this, there are some results where the separating function method [From the numerical results presented in OC value from 200 to 600 mm, the residual stud area can vary from 0.7 to 41%, for the most unfavourable cases. In addition, according to TG).From The biggest difference in the fire-resistance time of the insulation between the separating function method and the numerical results is 27%.TG).On average, the increase in fire resistance of insulation is 5 ± 0.4 min for each millimetre of gypsum thickness. This result is only valid for the currently used geometries and for the thickness of the gypsum layer  causes a small influence of the studs on the fire resistance of the structure. The fire resistance and the percentage of noncharred areas are reduced.An increase in the distance between the studs (H) results in a higher cavity thickness between both sides of the wall, which causes an increase in the fire resistance and a higher percentage of noncharred area.An increase in the cross-sectional thickness of the studs  , includeOC and depth H on the fire resistance of these LTF wall assemblies. Furthermore, it demonstrates that the separating function method [OC and H) on increasing its accuracy.Thus, the results obtained represent an important contribution in the study of LTF assemblies against fire resistance. This investigation shows the relevant effect of the distance n method , which i


The aim of this retrospective study was to determine the position of the impacted maxillary canine (IMC) and then to inspect the frequency, location, and extent of the consequent root resorption (RR) of the adjacent teeth by using CBCT.  Forty-one patients aged 12-68 who have 56 IMC detected on CBCT images were retrospectively examined in 3D. The canine position was determined by assessing the side of impaction, buccopalatal location, the distance of the canine cusp tip to the midline and to the occlusal plane, and canine angulation to the midline. RR of adjacent teeth was analyzed by investigating the nearest location of ectopic canine to adjacent teeth in horizontal and vertical dimensions in addition to measuring the degree of RR.  Twenty-seven (48.2%) impacted canines were on the right side, and 29 (51.8%) were on the left. Most of these teeth 31 (55.4%) were located palatally, while buccal impaction was seen in only 13 (23.2%) canines and 12 (21.4%) were located centrally. The mean distance of the ectopic canine cusp tip to the occlusal plane was significantly higher in males (14.4 mm) than in females (10.7 mm). RR was seen in 9 central incisors (31.03%) and 21 lateral incisors (41.17%) as well as one case in the first and second premolar. This RR was slight for all the adjacent central incisors and premolars.  IMC is more frequent in females, palatally and apically. When left untreated, it may cause RR of some of the adjacent teeth with various degrees, however, with no gender preference. Permanent tooth impaction usually results from failure of the tooth to emerge into its normal position in the dental arch within the usual period of growth –3. MaxilThe most frequent complication correlated to IMC is RR of the nearby lateral incisor , 6, 8. WThe conventional two-dimensional radiograph is the standard primary diagnostic technique used for the localization of IMC, planning treatment, and assessment of treatment outcomes , 6. HoweAs far as we know, no studies were carried out in Iraq to examine the effect of IMC on adjacent teeth and more specifically RR. Therefore, the aim of this retrospective study was to firstly assess the three-dimensional location of IMC in a sample of Iraqi population and secondly to investigate the frequency, location, and extent of RR of adjacent teeth by using CBCT.Over a period of two years (from July 2018 to August 2020), the CBCT of all patients referred for diagnostic and orthodontic purposes at a private clinic in Al-Hilla city, Babil, Iraq, were examined and only the ones with IMC (s) were selected to assess the unfavorable effect of IMC on adjacent teeth.Patients aged 12 years or olderPatients had been referred for a CBCT imaging because of ectopic eruption of one or both MC (s) as detected by clinical examinationThe inclusion criteria for the involved cases were as follows:Patients younger than 12 yearsPatients who had previous or ongoing orthodontic treatmentPatients who presented intraosseous pathosis related to the studied anterior maxillaPatients who had systemic disease or significant medical historyThe exclusion criteria included the following:A total of 41 CBCTs, 9 of males and 32 of females, aged 12-68 (mean 20.8 years) were retrospectively analyzed. These tomographs had 56 impacted canines, 26 of them were unilaterally IMC, and 15 had bilateral IMC . The choThe patients were scanned while in a standing position using a CS 9300 3D  with 8 × 8 cm field of view (FOV). The exposure parameters were 80 kVp, 10 mA, and 20 s. The CBCT images were assessed in all 3D  on a flat screen monitor by an orthodontist with 6 years of experience using the CS 3D imaging software .The 3D localization of the IMC include the following:Side of impaction )Buccopalatal location of IMC in the axial plane Transverse distance of the IMC cusp tip to the midline in the coronal plane Vertical distance of the IMC cusp tip to the occlusal plane in the sagittal plane Angulation of the IMC to the midline in the coronal plane (angle between the maxillary arch midline and the long axis of the IMC) (ii) RR of teeth adjacent to the IMC (s) was evaluated by determining these three variables:Nearest location of the IMC to the adjacent teeth in horizontal dimension  Nearest location of the IMC to the adjacent teeth in vertical dimension  The extent of RR was assessed by using Ericson and Kurol system , 19 withRadiographic variables of the fifty-six IMC (s) were examined and documented involving the following:t-test using SPSS (version 23) .Relations of the variables were tested by using chi-square test with Fisher's exact test, whereas variations in means between two groups were assessed by using independent sample Ten consecutive cases were reevaluated by a second experienced dentist to assess the interrater agreement. Kappa statistics (Cohen's kappa) was used to measure level of agreement for the categorical variables, and intraclass correlation (ICC) was used for the continuous variables.p < 0.05)  patients, and unilateral IMC was detected in 26  patients . In tota < 0.05) .p > 0.05). IMC cusp tip to the occlusal plane was significantly higher in males than in females (p < 0.05) (p > 0.05)  . Statist > 0.05) .p > 0.05).Most of the IMC (s) 51 (25 on the right and 26 on the left) approach the roots of the adjacent maxillary lateral incisors, whereas twenty-nine (14 on the right and 15 on the left) IMC (s) reach the roots of maxillary central incisors. Only one IMC was positioned ectopically posteriorly and was near the roots of the adjacent first and second premolars . More thp < 0.05).Approximately half of the IMC (s) adjacent to the central and lateral incisors were located at the apical third, whereas the IMC close to the first and second premolars was located at the cervical third of their roots . Signifip < 0.05).RR is detailed in The interrater agreement was excellent for all continuous variables as well as the buccopalatal location of the IMC and horizontal location of RR, whereas the agreement was substantial for the vertical location of RR and for the degree of RR .Orthodontic intervention to manage IMC (s) varies depending on its position within the maxillary arch in all three dimensions as well as its impact on the neighboring teeth, mainly whether it is causing root resorption of the adjacent teeth and if it did, to what extent that resorption can take place . TherefoThe present study involved scanning and analyzing the CBCT images of patients who have their upper anterior region scanned for diagnostic and orthodontic purposes. Therefore, the results of this study could be considered as a representative sample of patients who have IMC (s). The age group selected to be examined started from 12 years. This is because radiographic investigation of the MC is not required prior to ten years of age and potential IMC can only be seen for older age groups , 10.For gender distribution, the majority of the CBCTs were for females (78%) that were similar to the percentage reported in previous studies , 17, 20.Regarding buccopalatal location of the IMC, preceding studies , 15, 17 For the location of the ectopic canine, the mean distance of its cusps tip to the occlusal plane was 11.5 mm which was slightly higher than the values previously reported, , 25 whilOn the other hand, the mean vertical position of the impacted canine in relation to the occlusal plane was significantly higher in males (14.4 mm) than in females (10.7 mm). The reason for this difference is probably because males tend to have significantly larger dentoalveolar heights than females  making tMost of the IMC (s)  were in close proximity to the apical thirds of adjacent central and lateral incisors, whereas 27.6% of centrals and 33.3% of lateral incisors were at the middle thirds; 20.7% of centrals, 17.6% of laterals, and the only first and second premolars were at the cervical thirds which coincides with a preceding study .A wide divergence is present in reporting the prevalence of RR of teeth. This could be due to difference in the radiographic technique or imaging machine used, or it could be a result of variation in the population studied . As the Regarding the extent of RR, 69% of adjacent central incisors and 59% of adjacent lateral incisors had no RR. This leaves 31.03% of the neighboring central incisors and 41.17% of the adjacent lateral incisors as well as the first and second premolars having some sort of RR. The percentage for the lateral incisor RR was comparable to previous studies , 25. HowOnly three IMC (s) (5.36%) caused slight RR of both of the adjacent central and lateral incisors. This finding was similar to Ericson and Kurol's 2000) study  who foun000 studyNone of the adjacent central incisors and only one case (1.96%) of adjacent lateral incisors had severe RR, (3.9%) had moderate RR, whereas 35.3% had slight RR which was similar to a former study . This fiThe orthodontist and a pediatric dentist interrater agreement was consistent with the reliability reported previously , 22, 25.Ectopic eruption of MC occurs more frequently in females than in males by a 3.5-fold marginPalatal IMC was nearly two and a half times higher than buccal impactionMost of the IMC (s) were situated apically No significant difference was found between males and females for the three-dimensional position of the IMC apart from the vertical distance of the MC cusp tip to the occlusal planeRR affected approximately one-third of the adjacent teeth in untreated patients who have IMCWhen present, RR mostly involved adjacent lateral incisors (41%), followed by central incisors (31%), and the only case of first and second premolars (1.8%)The degree of RR was predominantly slight for all the affected neighboring teethGender was not significantly related to the RR of the neighboring teethThis study has derived the following conclusion with high interrater correlation: