A space-time mixed Galerkin marching-on-in-time scheme for the time-domain combined field integral equation

The time domain combined field integral equation (TD-CFIE), which is constructed from a weighted sum of the time domain electric and magnetic field integral equations (TD-EFIE and TD-MFIE) for analyzing transient scattering from closed perfect electrically conducting bodies, is free from spurious resonances. The standard marching-on-in-time technique for discretizing the TD-CFIE uses Galerkin and collocation schemes in space and time, respectively. Unfortunately, the standard scheme is theoretically not well understood: stability and convergence have been proven for only one class of space-time Galerkin discretizations. Moreover, existing discretization schemes are nonconforming, i.e., the TD-MFIE contribution is tested with divergence conforming functions instead of curl conforming functions. We therefore introduce a novel space-time mixed Galerkin discretization for the TD-CFIE. A family of temporal basis and testing functions with arbitrary order is introduced. It is explained how the corresponding interactions can be computed efficiently by existing collocation-in-time codes. The spatial mixed discretization is made fully conforming and consistent by leveraging both Rao-Wilton-Glisson and Buffa-Christiansen basis functions and by applying the appropriate bi-orthogonalization procedures. The combination of both techniques is essential when high accuracy over a broad frequency band is required

DNA Demethylation in Pluripotency and Reprogramming: The Role of Tet Proteins and Cell Division

Cytosine methylation is found in the genomes of many plants and animals and has been associated with transcriptional silencing in mammals. At critical stages in embryo development, when cellular potential is reset, DNA methylation is lost in a series of “sequential waves.” The mechanism underlying this is controversial and complex. Several new reports now suggest that TET enzymes and cell division are important for these in vivo transitions as well as for experimentally induced reprogramming

Earthquake Performance Investigation of a Masonry Building

This study investigated earthquake safety of a school building with a total construction area of 377 m2 based on Turkish Earthquake Code-2007 (TEC-2007). The architectural projects of the building were not present. Data regarding the details and sizes of the elements to be used in determining the capacities of the elements of the supporting systems of the existing buildings and information regarding the geometry and material characteristics of the supporting systems were achieved from observations and measurements to be carried out on the building. Then the measured system drawings were prepared for the building. Photographs revealing the current state of the building were taken and are presented in this study. How the performance of the building was evaluated was given in detail as step by step. By evaluating the performance of the building, the needed strengthening method was suggested to have an earthquake resistant building

Earthquake Safety Analysis of an Historical Masonry Building

In this study, how to study the earthquake safety of an Historical Masonry Residence that has wall damages because of soil sitting is shown. Restitution and restoration projects of the building are used in the analysis in addition to the site observation and research. The building has a basement, a ground floor, a normal floor and a half roof floor. The all walls of the basement and the outer walls of the other floors are made of stones. Inner walls are wood members. Stresses at the structural members are calculated by SAP2000 v.15 program. Planar stress analysis is made by SAP2000 v.15 program for ultimate loads. Structural members of building are modeled as shell member after the material properties are determined. Sittings of the building are considered as support settlement in the analysis. It is seen that most of the calculated stresses are lower than the limit stresses given in Turkish Seismic Code and only the basement walls have high stresses. These walls is strengthened by using FRP. Seismic behavior of residence is enhanced to demanded level by TSC-2007 with proposed strengthening metho

Investigating the Behaviour of Plaster Mortared Rural Masonry Walls

Turkey is located on the Alpine-Himalayan earthquake zone. %92 of its land is faced with earthquake hazard. Even in low intensity earthquakes, major damages have been observed in masonry structures. Masonry structures which are built without any technical support constitute the %40-45 of the structures in Turkey. Therefore, these structures cause losses of lives and remarkable economic in earthquakes. Studies on earthquake resistant structural designs focus on reinforced concrete and steel structures. Researches on masonry structures which are especially preferred in rural areas in Turkey. However, earthquakes negatively affect the masonry structures more than reinforced concrete and steel ones. In the scope of this study, behavior of plaster mixed walls which increase the strength of masonry structures is studied. For this purpose, strength values of normal plaster mixed regular walls with blend bricks and polypropylene and steel fiber mixed masonry walls are analyzed. Double-row and 45x45 mm sized normal mortared wall which is specially produced by 1:2 scaled blend bricks having 100x50x30 mm size values and walls that are formed by polypropylene and steel fiber additives are exposed to biaxial load in several angles. Stress-envelope equations are obtained due to strength of masonry walls bonded by plaster mixed blend bricks. Obtained curves make an important contribution to determine the realistic behavior of polypropylene and steel fiber plastered masonry walls