Inelastic response and effective design of asymmetric buildings under strong earthquake loading

Asymmetric building structures arise frequently in civil engineering practice as a result of architectural or other requirements. Collapse and widespread severe damage of buildings associated with the torsional response created by structural asymmetry or other forms of irregularity have been observed repeatedly in past strong earthquakes. This highlights the inadequacies in current earthquake resistant design and construction of asymmetric buildings in seismic prone regions. This thesis investigates the inelastic behaviour of asymmetric buildings under strong earthquake motions and provides guidelines and recommendations for their effective design. These guidelines are widely applicable, offer conservative estimates of design loadings for individual resisting elements, and retain simplicity for ease of code implementation. A comprehensive review and critical assessment of previous studies are presented in which the different approaches and contradictory conclusions reached are identified. Prior to inelastic dynamic studies, an inelastic failure mode analysis of single-storey asymmetric buildings under static monotonic loading is carried out. The latter analysis helps to explain the model dependency of the inelastic torsional response and clarifies the influence of key system parameters. Based on single-storey building models, the model dependency of the inelastic torsional response is studied further by carrying out inelastic earthquake response analysis. A suitable analytical model is developed, which provides conservative estimates of the inelastic torsional effects, represents a wide range of actual buildings, is simply defined and facilitates the straightforward interpretation of results. A thorough inelastic dynamic parametric study is carried out employing this model, leading to improved understanding of the inelastic behaviour of asymmetric buildings to strong earthquake motions and the influence of key system parameters on the inelastic seismic response. The torsional provisions of current earthquake resistant design building codes from Europe, New Zealand, Canada, Mexico and the United States are rigorously evaluated based on the analysis of the single-storey building model. In particular, an assessment is made of the adequacy of the linear elastic modal analysis procedure, which is specified in most codes as an alternative approach to the equivalent static force procedure for the design of asymmetric buildings when certain regularity conditions are not satisfied. Inadequacies in the code torsional provisions and the linear elastic modal analysis procedure are identified. Improvements to these code provisions are sought and a new unified approach for torsional design is proposed. A multistorey regularly asymmetric frame building model is also developed, and the code torsional provisions and the linear elastic modal analysis method are re-evaluated based on this model. The results of this study reinforce the conclusions obtained from analysis of the single-storey model and provide insight into the effect of inelastic torsional coupling in the various storeys of the building. A new equivalent static force procedure is proposed for the design of multistorey regularly asymmetric frame buildings. As a result of its inadequacies, it is suggested that linear elastic modal analysis be deleted as an alternative method for design of these buildings

Riesz basis property of the generalized eigenvector system of a Timoshenko beam

The Riesz basis property of the generalized eigenvector system of a Timoshenko beam with boundary feedback controls applied to two ends is studied in this paper. The spectral property of the operator A determined by the closed loop system is investigated. It is shown that operator A has compact resolvent and generates a C 0 semigroup, and its spectrum consists of two branches and has two asymptotes under some conditions. Furthermore it is proved that the sequence of all generalized eigenvectors of the system principal operator forms a Riesz basis for the state Hilbert space.postprin

Optimizing culture medium for debittering constitutive enzyme naringinase production by Aspergillus oryzae JMU316

The objective of this study was to investigate nutrient requirements for extracellular constitutive naringinase production by Aspergillus oryzae JMU316. The one-factor-at-a-time method was used to determine the impact of different carbon and nitrogen sources on naringinase production. Naringin exhibited the highest naringinase activity compared to all other carbon sources and pomelo pericarp powder produced comparable naringinase activity. Pomelo pericarp powder was selected as carbon source because it is a waste of fruit process, which means that it is a cheap resource and has additional environmental benefits. Peptone proved to be the most suitable nitrogen source for naringinase production. Subsequently, the orthogonal matrix method was used to further optimize the concentration of pomelo pericarp powder, peptone, and minerals. The optimal concentration of the components were15 g pomelo pericarp powder, 12 g peptone, 0.2 g CaCl2, 0.4 g NaCl, 2 g MgSO4·7H2O and 1 g K2HPO4 in 1 L distilled water for producing 408.28 IU/mL naringinase activity. The effects of medium components on naringinase were in the order of pomelo pericarp powder, K2HPO4, NaCl, peptone, CaCl2, MgSO4·7H2O. This two-step optimization strategy used in this study can be widely applied to other microbial fermentation processes.Key words: Pomelo pericarp powder, orthogonal matrix method, naringinase, culture medium optimization, Aspergillus oryzae JMU316

Electrically controllable surface magnetism on the surface of topological insulator

We study theoretically the RKKY interaction between magnetic impurities on the surface of three-dimensional topological insulators, mediated by the helical Dirac electrons. Exact analytical expression shows that the RKKY interaction consists of the Heisenberg-like, Ising-like and DM-like terms. It provides us a new way to control surface magnetism electrically. The gap opened by doped magnetic ions can lead to a short-range Bloembergen-Rowland interaction. The competition among the Heisenberg, Ising and DM terms leads to rich spin configurations and anomalous Hall effect on different lattices.Comment: 5 pages, 3 figures, 1 tabl

Isolation of dimorphic chloroplasts from the single-cell C4 species Bienertia sinuspersici

Three terrestrial plants are known to perform C4 photosynthesis without the dual-cell system by partitioning two distinct types of chloroplasts in separate cytoplasmic compartments. We report herein a protocol for isolating the dimorphic chloroplasts from Bienertia sinuspersici. Hypo-osmotically lysed protoplasts under our defined conditions released intact compartments containing the central chloroplasts and intact vacuoles with adhering peripheral chloroplasts. Following Percoll step gradient purification both chloroplast preparations demonstrated high homogeneities as evaluated from the relative abundance of respective protein markers. This protocol will open novel research directions toward understanding the mechanism of single-cell C4 photosynthesis

On the role of magnetic reconnection in jet/accretion disk systems

The most accepted model for jet production is based on the magneto-centrifugal acceleration out off an accretion disk that surrounds the central source (Blandford & Payne, 1982). This scenario, however, does not explain, e.g., the quasi-periodic ejection phenomena often observed in different astrophysical jet classes. de Gouveia Dal Pino & Lazarian (2005) (hereafter GDPL) have proposed that the large scale superluminal ejections observed in microquasars during radio flare events could be produced by violent magnetic reconnection (MR) episodes. Here, we extend this model to other accretion disk systems, namely: active galactic nuclei (AGNs) and young stellar objects (YSOs), and also discuss its role on jet heating and particle acceleration.Comment: To be published in the IAU Highlights of Astronomy, Volume 15, XXVII IAU General Assembly, August 2009, Ian F. Corbett et al., eds., 201

Development of mHealth system for supporting self-management and remote consultation of skincare eHealth/ telehealth/ mobile health systems

Background: Individuals with spina bifida (SB) are vulnerable to chronic skin complications such as wounds on the buttocks and lower extremities. Most of these complications can be prevented with adherence to self-care routines. We have developed a mobile health (mHealth) system for supporting self-care and management of skin problems called SkinCare as part of an mHealth suite called iMHere (interactive Mobile Health and Rehabilitation). The objective of this research is to develop an innovative mHealth system to support self-skincare tasks, skin condition monitoring, adherence to self-care regimens, skincare consultation, and secure two-way communications between patients and clinicians. Methods: In order to support self-skincare tasks, the SkinCare app requires three main functions: (1) self-care task schedule and reminders, (2) skin condition monitoring and communications that include imaging, information about the skin problem, and consultation with clinician, and (3) secure two-way messaging between the patient and clinician (wellness coordinator). The SkinCare system we have developed consists of the SkinCare app, a clinician portal, and a two-way communication protocol connecting the two. The SkinCare system is one component of a more comprehensive system to support a wellness program for individuals with SB. Results: The SkinCare app has several features that include reminders to perform daily skin checks as well as the ability to report skin breakdown and injury, which uses a combination of skin images and descriptions. The SkinCare app provides reminders to visually inspect one's skin as a preventative measure, often termed a "skin check." The data is sent to the portal where clinicians can monitor patients' conditions. Using the two-way communication, clinicians can receive pictures of the skin conditions, track progress in healing over time, and provide instructions for how to best care for the wound. Conclusions: The system was capable of supporting self-care and adherence to regimen, monitoring adherence, and supporting clinician engagement with patients, as well as testing its feasibility in a long-term implementation. The study shows the feasibility of a long-term implementation of skincare mHealth systems to support self-care and two-way interactions between patients and clinicians

Development of human single-chain antibodies against SARS-associated coronavirus.

The outbreak of severe acute respiratory syndrome (SARS), caused by a distinct coronavirus, in 2003 greatly threatened public health in China, Southeast Asia as well as North America. Over 1,000 patients died of the SARS virus, representing 10% of infected people. Like other coronaviruses, the SARS virus also utilizes a surface glycoprotein, namely the spike protein, to infect host cells. The spike protein of SARS virus consists of 1,255 amino acid residues and can be divided into two sub-domains, S1 and S2. The S1 domain mediates the binding of the virus to its receptor angiotensin-converting enzyme 2, which is abundantly distributed on the surface of human lung cells. The S2 domain mediates membrane fusion between the virus and the host cell. Hence two strategies can be used to block the infection of the SARS virus, either by interfering with the binding of the S1 domain to the receptor or by blocking the fusion of the virus with the cell membrane mediated by the S2 domain. Several antibodies against the S1 domain have been generated and all of them are able to neutralize the virus in vitro and in vivo using animal models. Unfortunately, point mutations have been identified in the S1 domain, so that the virus isolated in the future may not be recognized by these antibodies. As no mutation has been found in the S2 domain indicating that this region is more conserved than the S1 domain, it may be a better target for antibody binding. After predicting the immunogenicity of the epitopes of the S2 domain, we chemically synthesized two peptides and also expressed one of them using a recombinant DNA method. We screened a phage displaying library of human single-chain antibodies (ScFv) against the predicted epitopes and obtained a human ScFv which can recognize the SARS virus in vitro