Quasi-Static Nonlinear Seismic Assessment of a Fourth Century A.D. Roman Aqueduct in Istanbul, Turkey

The majority of architectural heritage consists of load-bearing masonry components made up of stone units and relatively weak mortar joints, yielding potential weak planes for masonry structures where tension and shear failures are expected to occur. Advanced nonlinear analyses are required to simulate these phenomena and predict the corresponding nonlinear structural behavior of historic masonry constructions. In this context, this paper presents a model of a stone masonry Roman aqueduct (the Valens Aqueduct), constructed in the fourth century A.D. in Istanbul, Turkey, to explore the seismic capacity and behavior using the discrete element method (DEM). The employed modeling approach comprises distinct rigid blocks interacting along their boundaries based on the point-contact hypothesis. Thus, the discontinuous stone skeleton of the masonry aqueduct is represented explicitly in the computational model. First, a validation study was conducted on the laboratory experiment to demonstrate the capabilities of the adopted modeling approach. Then, a discontinuum model representing the Valens Aqueduct was used to assess the seismic capacity of the structure under gradually increasing lateral forces. The numerical simulations gave insight into the structural response of the aqueduct from the elastic range to total collapse. Additionally, parametric research was performed considering joint properties, namely the joint tensile strength, contact stiffness, joint friction angle, and compressive strength of the masonry, to quantify the effects of contact parameters on the displacement response of the DEM model. Further inferences were made regarding the modeling parameters, and practical conclusions were derived

Tensile fracture mechanism of masonry wallettes parallel to bed joints: A stochastic discontinuum analysis

Nonhomogeneous material characteristics of masonry lead to complex fracture mechanisms, which require substantial analysis regarding the influence of masonry constituents. In this context, this study presents a discontinuum modeling strategy, based on the discrete element method, developed to investigate the tensile fracture mechanism of masonry wallettes parallel to the bed joints considering the inherent variation in the material properties. The applied numerical approach utilizes polyhedral blocks to represent masonry and integrate the equations of motion explicitly to compute nodal velocities for each block in the system. The mechanical interaction between the adjacent blocks is computed at the active contact points, where the contact stresses are calculated and updated based on the implemented contact constitutive models. In this research, different fracture mechanisms of masonry wallettes under tension are explored developing at the unit–mortar interface and/or within the units. The contact properties are determined based on certain statistical variations. Emphasis is given to the influence of the material properties on the fracture mechanism and capacity of the masonry assemblages. The results of the analysis reveal and quantify the importance of the contact properties for unit and unit–mortar interfaces (e.g., tensile strength, cohesion, and friction coefficient) in terms of capacity and corresponding fracture mechanism for masonry wallettes.This research received no external funding

Quasi-static nonlinear seismic assessment of a fourth century A.D. Roman Aqueduct in Istanbul, Turkey

© 2021 by the authors. Licensee MDPI, Basel, Switzerland.The majority of architectural heritage consists of load-bearing masonry components made up of stone units and relatively weak mortar joints, yielding potential weak planes for masonry structures where tension and shear failures are expected to occur. Advanced nonlinear analyses are required to simulate these phenomena and predict the corresponding nonlinear structural behavior of historic masonry constructions. In this context, this paper presents a model of a stone masonry Roman aqueduct (the Valens Aqueduct), constructed in the fourth century A.D. in Istanbul, Turkey, to explore the seismic capacity and behavior using the discrete element method (DEM). The employed modeling approach comprises distinct rigid blocks interacting along their boundaries based on the point-contact hypothesis. Thus, the discontinuous stone skeleton of the masonry aqueduct is represented explicitly in the computational model. First, a validation study was conducted on the laboratory experiment to demonstrate the capabilities of the adopted modeling approach. Then, a discontinuum model representing the Valens Aqueduct was used to assess the seismic capacity of the structure under gradually increasing lateral forces. The numerical simulations gave insight into the structural response of the aqueduct from the elastic range to total collapse. Additionally, parametric research was performed considering joint properties, namely the joint tensile strength, contact stiffness, joint friction angle, and compressive strength of the masonry, to quantify the effects of contact parameters on the displacement response of the DEM model. Further inferences were made regarding the modeling parameters, and practical conclusions were derived

Effects of spatial variability and correlation in stochastic discontinuum analysis of unreinforced masonry walls

This study investigates the influence of the uncertainty in material properties on the in-plane lateral behavior and capacity of stone masonry walls via a stochastic discontinuum analysis framework. The framework is demonstrated via the 3D numerical assessment of an unreinforced masonry (URM) wall using a stochastic analysis in the form of Monte Carlo simulations. The random parameters considered in this study are the prism compressive strength of masonry, the tensile strength of the masonry units and joints, and the friction angle for joints and units. Novel research is conducted using a fast and accurate DEM model to determine whether the spatial variability of the material properties should be taken into account. In addition, the effects of joint-to-joint correlation of modeling parameters are examined to identify if such a correlation exists. A total of 1200 stochastic discontinuum analyses for 12 different cases are carried out. The results call attention to considering the spatial variability of the modeling parameters in the stochastic analysis, as they significantly reduce the variation in the wall’s strength and displacement capacity. Results also demonstrate the influence of the correlation between bedjoint parameters on the strength and failure mode of the walls. Ultimately, propagation of the uncertainty in the joint friction angle into the strength and displacement capacity of the walls is quantified

GENETIC DIVERSITY OF CROCUS SATIVUS AND ITS CLOSE RELATIVE SPECIES ANALYZED BY iPBS-RETROTRANSPOSONS

Saffron (Crocus L.) is a member of Crocoideae, the biggest of four subfamilies in the Iridaceae family. It has 2n = 3x = 24 chromosomes and is triploid; thus, it is sterile. In previous research, different molecular DNA markers were used but molecular characterization and genetic diversity of this complex genus have not yet been clarified. Therefore, current study aimed to determine the molecular characterization of saffron and its close relative species using inter-primer binding site (iPBS)-retrotransposon markers. Eighty-three iPBSretrotransposon primers were used in 28 C. sativus genotypes and 17 close relative species of saffron to identify their genetic diversity. Sixteen polymorphic iPBS-retrotransposon primers generated a total of 401 polymorphic scorable bands. The mean PIC value, Nei’s genetic diversity and Shannon’s information index (I) were calculated as 0.85, 0.16 and 0.29, respectively. The results of the Unweighted Pair Group Method with Arithmetic mean UPGMA dendrogram and Principal Coordinates Analysis PCoA analysis indicated a spatial representation of the relative genetic distances among 28 saffron samples and the 17 close relative species were categorized under two distinct groups. Saffron genotypes showed very limited genetic variation and according to the iPBS-retrotransposon data, its close relatives were C. cartwrightianus and C. pallasii subsp. pallasiiSaffron (Crocus L.) is a member of Crocoideae, the biggest of four subfamilies in the Iridaceae family. It has 2n = 3x = 24 chromosomes and is triploid; thus, it is sterile. In previous research, different molecular DNA markers were used but molecular characterization and genetic diversity of this complex genus have not yet been clarified. Therefore, current study aimed to determine the molecular characterization of saffron and its close relative species using inter-primer binding site (iPBS)-retrotransposon markers. Eighty-three iPBSretrotransposon primers were used in 28 C. sativus genotypes and 17 close relative species of saffron to identify their genetic diversity. Sixteen polymorphic iPBS-retrotransposon primers generated a total of 401 polymorphic scorable bands. The mean PIC value, Nei’s genetic diversity and Shannon’s information index (I) were calculated as 0.85, 0.16 and 0.29, respectively. The results of the Unweighted Pair Group Method with Arithmetic mean UPGMA dendrogram and Principal Coordinates Analysis PCoA analysis indicated a spatial representation of the relative genetic distances among 28 saffron samples and the 17 close relative species were categorized under two distinct groups. Saffron genotypes showed very limited genetic variation and according to the iPBS-retrotransposon data, its close relatives were C. cartwrightianus and C. pallasii subsp. pallasi

GENETIC DIVERSITY OF CROCUS SATIVUS AND ITS CLOSE RELATIVE SPECIES ANALYZED BY iPBS-RETROTRANSPOSONS

WOS: 000418419700011Saffron (Crocus L.) is a member of Crocoideae, the biggest of four subfamilies in the Iridaceae family. It has 2n = 3x = 24 chromosomes and is triploid; thus, it is sterile. In previous research, different molecular DNA markers were used but molecular characterization and genetic diversity of this complex genus have not yet been clarified. Therefore, current study aimed to determine the molecular characterization of saffron and its close relative species using inter-primer binding site (iPBS)-retrotransposon markers. Eighty-three iPBS-retrotransposon primers were used in 28 C. sativus genotypes and 17 close relative species of saffron to identify their genetic diversity. Sixteen polymorphic iPBS-retrotransposon primers generated a total of 401 polymorphic scorable bands. The mean PIC value, Nei's genetic diversity and Shannon's information index (I) were calculated as 0.85, 0.16 and 0.29, respectively. The results of the Unweighted Pair Group Method with Arithmetic mean UPGMA dendrogram and Principal Coordinates Analysis PCoA analysis indicated a spatial representation of the relative genetic distances among 28 saffron samples and the 17 close relative species were categorized under two distinct groups. Saffron genotypes showed very limited genetic variation and according to the iPBS-retrotransposon data, its close relatives were C. cartwrightianus and C. pallasii subsp. pallasii.University of Cukurova, Scientific Research Projects UnitCukurova University [FBA-2014-2704]The authors express their gratitude to University of Cukurova, Scientific Research Projects Unit for their financial support (FBA-2014-2704)

In-plane structural performance of dry-joint stone masonry Walls: A spatial and non-spatial stochastic discontinuum analysis

In this study, the in-plane structural behavior, capacity, and performance of dry-joint stone masonry walls (DJ- SMWs) and the effects of the vertical stress level on these factors are investigated via a stochastic discontinuum analysis that considers the material uncertainty. A discontinuum type of analysis is performed based on the discrete element method (DEM), where each stone masonry unit is explicitly represented in the computational model. To better simulate the cracking and shear failure modes within the stone units, a coupled fracture energy- based contact constitutive model is implemented into a commercial discrete element code, 3DEC. First, the proposed modeling approach is validated by comparing to experimental findings in literature. Then, the approach is used to explore the failure mechanism and the force–displacement behavior of DJ-SMWs, considering different vertical stress levels and material properties. The results of the novel modeling strategy provide a better understanding of the progressive collapse mechanism of DJ-SMWs and the influence of the vertical stress level. Furthermore, the outcomes of this research indicate the major role of the frictional resistance at the joints in the safety and performance assessment of the dry-joint load-bearing masonry walls. Finally, important inferences are made regarding the non-spatial and spatial stochastic discontinuum analysis

Association mapping of loci linked to copper, phosphorus, and potassium concentrations in the seeds of C. arietinum and C. reticulatum

Otles, Semih/0000-0003-4571-8764; Ozkuru, Esin/0000-0003-0282-783XWOS: 000495876600077PubMed: 30594584Due to its high nutritional value, chickpea is one of the most important and cost-effective legumes for human diet. Nutrient elements, such as Cu, P, K have numerous essential functions for the human metabolism. in this study, association mapping of loci linked to the seed Cu, P and K concentrations were performed on a population consisting of 107 Cicer reticulatum and 73 Cicer arietinum individuals in four environments (two locations x two years). A total of 121,840 SNPs were genotyped across 180 individuals by GBS analysis. the association mapping between the SNP markers and the seed Cu, P, K concentrations were identified and eight SNPs were found to be significantly associated with variations in three nutrient elements in more than two environments This research suggests that association mapping is a useful methodology for the identification of loci controlling the Cu, P and K uptake in chickpea seeds for further association mapping, molecular breeding, and marker-assisted selection and plant breeding studies and provides a broader understanding of the relationship between the investigated Cicer species and the effects of environmental conditions.Scientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [214O278]This work was supported by the Scientific and Technological Research Council of Turkey (TUBITAK) with the project number of 214O278

In-plane structural performance of dry-joint stone masonry Walls: a spatial and non-spatial stochastic discontinuum analysis

In this study, the in-plane structural behavior, capacity, and performance of dry-joint stone masonry walls (DJSMWs) and the effects of the vertical stress level on these factors are investigated via a stochastic discontinuum analysis that considers the material uncertainty. A discontinuum type of analysis is performed based on the discrete element method (DEM), where each stone masonry unit is explicitly represented in the computational model. To better simulate the cracking and shear failure modes within the stone units, a coupled fracture energybased contact constitutive model is implemented into a commercial discrete element code, 3DEC. First, the proposed modeling approach is validated by comparing to experimental findings in literature. Then, the approach is used to explore the failure mechanism and the force-displacement behavior of DJ-SMWs, considering different vertical stress levels and material properties. The results of the novel modeling strategy provide a better understanding of the progressive collapse mechanism of DJ-SMWs and the influence of the vertical stress level. Furthermore, the outcomes of this research indicate the major role of the frictional resistance at the joints in the safety and performance assessment of the dry-joint load-bearing masonry walls. Finally, important inferences are made regarding the non-spatial and spatial stochastic discontinuum analysis.- (undefined