Comparison of experimental and analytically predicted out-of-plane behavior of framed-masonry walls containing openings

During an earthquake, structures are loaded in both in-plane and out-of-plane direction. This paper investigates the behaviour of load-bearing frames with infill walls that contain openings. As when they are subjected to out-of-plane, inertial loads. In the experimental campaigns of like structures, it was found that even with openings, the beneficial arching-action was able to develop. However, its effectiveness was limited. Namely, the deformation capabilities in all cases were significantly lowered. Same can not be stated for the load-bearing capacities, as some researches found no reduction while others did. Additionally, this paper analyses the existing equations that can calculate the load-bearing capacity of such structures. Low correlations were found between the experimental and analytical capacities. Hence, further research endeavours should be addressed in order to gain a reliable analytical model

A review of experimental and analytical studies on the out-of-plane behaviour of masonry infilled frames

This paper presents a literature review of research undertaken on the out-of-plane behaviour of masonry infilled frames. This paper also discusses the effects of bidirectional loads, openings, slenderness, boundary conditions etc. As numerous researchers have reported, these effects play a crucial role in achieving arching action cause, as they can bypass or limit its effectiveness. Namely, arching action leads to additional compressive forces which resist traversal ones. This is confirmed by inertial force methods of testing, while the same cannot be claimed for inter-storey drift or dynamical methods. It is to be acknowledged that most experimental tests were carried out using inertial force methods, mostly with the use of airbags. In contrast, only a few were undertaken with dynamical methods and just two with inter-storey drift methods. It was found that inertial force and inter-storey drift methods differ widely. In particular, inertial force methods damage the infill, leaving the frame more or less intact. Conversely, drift heavily damages the frame, while infill only slightly. Openings were investigated, albeit with contrasting results. Namely, in all cases, it was found that openings do lower the deformational but not all load-bearing capacities. Furthermore, analytical models have shown contrasting results between themselves and with experimental data. Models’ stabilities were checked with single- and multi-variable parametric analysis from which governing factors, influences of frame and other parameters were identified

Development and Calibration of a 3D Micromodel for Evaluation of Masonry Infilled RC Frame Structural Vulnerability to Earthquakes

Within the scope of literature, the influence of openings within the infill walls that are bounded by a reinforced concrete frame and excited by seismic drift forces in both in- and out-of-plane direction is still uncharted. Therefore, a 3D micromodel was developed and calibrated thereafter, to gain more insight in the topic. The micromodels were calibrated against their equivalent physical test specimens of in-plane, out-of-plane drift driven tests on frames with and without infill walls and openings, as well as out-of-plane bend test of masonry walls. Micromodels were rectified based on their behavior and damage states. As a result of the calibration process, it was found that micromodels were sensitive and insensitive to various parameters, regarding the model’s behavior and computational stability. It was found that, even within the same material model, some parameters had more effects when attributed to concrete rather than on masonry. Generally, the in-plane behavior of infilled frames was found to be largely governed by the interface material model. The out-of-plane masonry wall simulations were governed by the tensile strength of both the interface and masonry material model. Yet, the out-of-plane drift driven test was governed by the concrete material properties

Kinetic modelling of testosterone-related differences in the hypothalamic–pituitary–adrenal axis response to stress

The sex hormone testosterone (TTS) and the hypothalamic–pituitary–adrenal (HPA) axis mutually control one another’s activity, wherein TTS suppresses corticotrophin releasing hormone (CRH) stimulated HPA axis activity, whereas the activation of HPA axis has an inhibitory effect on TTS secretion. With an intention to explain these phenomena, a network reaction model is developed from the previously postulated stoichiometric models for HPA activity where main dynamic behaviors are controlled by two catalytic steps (one autocatalytic and one autoinhibitory) with respect to cortisol, both found experimentally. The capacity of the model to emulate TTS effects on HPA axis dynamics and its response to acute CRH-induced stress is examined using numerical simulations. Model predictions are compared with empirically obtained results reported in the literature. Thus, the reaction kinetic examinations of nonlinear biochemical transformations that constitute the HPA axis, including the negative feedback effect of TTS on HPA axis activity, recapitulates the well-established fact that TTS dampens HPA axis basal activity, decreasing both cortisol level and the amplitude of ultradian cortisol oscillations. The model also replicates TTS inhibitory action on the HPA axis response to acute environmental challenges, particularly CRH-induced stress. In addition, kinetic modelling revealed that TTS induced reduction in ultradian cortisol amplitude arises because the system moves towards a supercritical Hopf bifurcation as TTS is being increased. © 2017, The Author(s)

Genetic Differentiation of the Western Capercaillie Highlights the Importance of South-Eastern Europe for Understanding the Species Phylogeography

The Western Capercaillie (Tetrao urogallus L.) is a grouse species of open boreal or high altitude forests of Eurasia. It is endangered throughout most mountain range habitat areas in Europe. Two major genetically identifiable lineages of Western Capercaillie have been described to date: the southern lineage at the species' southernmost range of distribution in Europe, and the boreal lineage. We address the question of genetic differentiation of capercaillie populations from the Rhodope and Rila Mountains in Bulgaria, across the Dinaric Mountains to the Slovenian Alps. The two lineages' contact zone and resulting conservation strategies in this so-far understudied area of distribution have not been previously determined. The results of analysis of mitochondrial DNA control region sequences of 319 samples from the studied populations show that Alpine populations were composed exclusively of boreal lineage; Dinaric populations of both, but predominantly (96%) of boreal lineage; and Rhodope-Rila populations predominantly (>90%) of southern lineage individuals. The Bulgarian mountains were identified as the core area of the southern lineage, and the Dinaric Mountains as the western contact zone between both lineages in the Balkans. Bulgarian populations appeared genetically distinct from Alpine and Dinaric populations and exhibited characteristics of a long-term stationary population, suggesting that they should be considered as a glacial relict and probably a distinct subspecies. Although all of the studied populations suffered a decline in the past, the significantly lower level of genetic diversity when compared with the neighbouring Alpine and Bulgarian populations suggests that the isolated Dinaric capercaillie is particularly vulnerable to continuing population decline. The results are discussed in the context of conservation of the species in the Balkans, its principal threats and legal protection status. Potential conservation strategies should consider the existence of the two lineages and their vulnerable Dinaric contact zone and support the specificities of the populations

The oscillatory Bray-Liebhafsky reaction as a matrix for analyzing enzyme and polymeric catalysts for hydrogen peroxide

The Bray-Liebhafsky (BL) oscillatory reaction, as a reaction where hydrogen peroxide decomposes into the water and oxygen in the presence of iodate and hydrogen ions through a complex mechanism involving a number of intermediates, such as I-, I2, HIO and HIO2, was used as the matrix for analysis of kinetic properties of the catalysts for hydrogen peroxide decomposition. The examined catalysts were enzyme peroxidase (isolated from the horseradish root) and polymeric catalyst (acid form of poly-4-vynil-pyridine functionalized by fericsulfate). The change of kinetic state of the system caused by the presence of added catalyst is reflected in the form of oscillograms, in the time elapsed from the beginning of the reaction to the first oscillation, in the time elapsed from the beginning of the reaction to the end of oscillatory evolution, the number of oscillations, the average period between oscillations and its frequency. Since all these kinetic properties depend on the added amounts of both mentioned catalysts in a complex but analogous manner, a similar reaction mechanism could be expected in both cases.Braj-Liebhafski (BL) oscilatorna reakcija, kao reakcija u kojoj se vodonik-peroksid, u prisustvu jodata i vodoničnih jona, razlaže na vodu i kiseonik, po kompleksnom mehanizmu koji uključuje nastanak brojnih intermedijera kao što su I-, I2, HIO i HIO2 je korišćena kao matrica za analizu kinetičkih osobina katalizatora za razlaganje vodonik-peroksida. Ispitivani katalizatori su peroksidaza izolovana iz korena rena i sintetički polimer (kiseli oblik poli-4-vinil-piridina funkcionalizovanog sa ferisulfatom). Promene kinetičkog stanja sistema izazvane prisustvom dodatih količina katalizatora se reflektuju na formu oscilograma, na vreme proteklo od početka reakcije do pojave prve oscilacije, na vreme proteklo od početka reakcije do kraja oscilatorne evolucije, broj oscilacija, srednjeg perioda oscilovanja i njihovu frekvenciju. Kako sva ova kinetička svojstva zavise od dodatih količina katalizatora na kompleksan ali analogan način, sličan reakcioni mehanizam se može očekivati u oba slučaja

Structures of chaos in open reaction systems

By numerically simulating the Bray-Liebhafsky (BL) reaction (the hydrogen peroxide decomposition in the presence of hydrogen and iodate ions) in a continuously fed well stirred tank reactor (CSTR), we find "structured" types of chaos emerging in regular order with respect to flow rate as the control parameter. These chaotic "structures" appear between each two successive periodic states, and have forms and evolution resembling to the neighboring periodic dynamics. More precisely, in the transition from period-doubling route to chaos to the arising periodic mixture of different mixed-mode oscillations, we are able to recognize and qualitatively and quantitatively distinguish the sequence of "period-doubling" chaos and chaos consisted of mixed-mode oscillations (the "mixed-mode structured" chaos), both appearing in regular order between succeeding periodic states. Additionally, between these types of chaos, the chaos without such recognizable "structures" ("unstructured" chaos) is also distinguished. Furthermore, all transitions between two successive periodic states are realized through bifurcation of chaotic states. This scenario is a universal feature throughout the whole mixed-mode region, as well as throughout other mixed-mode regions obtained under different initial conditions