Search results for "structures"
showing 10 items of 4815 documents
Structural Vibration Control for a Class of Connected Multistructure Mechanical Systems
2012
Published version of an article from the journal: Mathematical Problems in Engineering. Also available from the publisher:http://dx.doi.org/10.1155/2012/942910 A mathematical model to compute the overall vibrational response of connected multistructure mechanical systems is presented. Using the proposed model, structural vibration control strategies for seismic protection of multibuilding systems can be efficiently designed. Particular attention is paid to the design of control configurations that combine passive interbuilding dampers with local feedback control systems implemented in the buildings. These hybrid active-passive control strategies possess the good properties of passive contro…
Discrete-time multioverlapping controller design for structural vibration control of tall buildings under seismic excitation
2012
Published version of an article from the journal: Mathematical Problems in Engineering. Also available from the publisher:http://dx.doi.org/10.1155/2012/636878 In this paper, a computationally effective strategy to obtain multioverlapping controllers via the Inclusion Principle is applied to design discrete-time state-feedback multioverlapping LQR con- trollers for seismic protection of tall buildings. To compute the corresponding control actions, the proposed semidecentralized controllers only require state information from neighboring stories. This particular configuration of information exchange allows introducing a dramatic reduction in the transmission range required for a wireless imp…
Active-passive control strategy for adjacent buildings
2011
Author's version of a chapter in the book: 2011 Proceedings of the American Control Conference. Also available from the publisher at: http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=05991059 In this paper, a control strategy to mitigate the vibrational response of adjacent buildings under seismic excitation is presented. The proposed strategy combines inter-building passive actuators with active actuators placed in the building stories. The main ideas are presented by means of a simplified two-building model; however, a semi-decentralized overlapping approach via the inclusion principle has been used to impose a proper information exchange structure suitable for wireless control of larg…
Semi-decentralized strategies in structural vibration control
2011
Published version of an article published in the journal: Modeling, Identification and Control. Also available from the publisher at: http://dx.doi.org/10.4173/mic.2011.2.2 In this work, the main ideas involved in the design of overlapping and multi-overlapping controllers via the Inclusion Principle are discussed and illustrated in the context of the Structural Vibration Control of tall buildings under seismic excitation. A detailed theoretical background on the Inclusion Principle and the design of overlapping controllers is provided. Overlapping and multi-overlapping LQR controllers are designed for a simplied five-story building model. Numerical simulations are conducted to asses the pe…
Does it take two to tango? Factors related to the ease of societal uptake of scientific knowledge
2016
Science policy increasingly focuses on maximising societal benefits from science and technology investments, but often reduces those benefits to activities involving codifying and selling knowledge, thereby idealising best practice academic behaviours around entrepreneurial superstars. This paper argues that societal value depends on knowledge being used, making knowledge's eventual exploitation partly dependent upon on whether other users-societal or scientific-can use that knowledge (i.e. on how far new knowledge is cognate with users' existing knowledge). When scientists incorporate user knowledge into their research processes, what we call 'open research behaviours', their knowledge may…
Natural optical anisotropy of h-BN: Highest giant birefringence in a bulk crystal through the mid-infrared to ultraviolet range
2018
The giant birefringence of layered h-BN was demonstrated by analyzing the interference patterns in reflectance and transmittance measurements in the mid-infrared to the deep ultraviolet energy range. The refractive index for polarization perpendicular to the c axis is much higher than the refractive index for polarization parallel to the c axis, and it displays a strong increase in the ultraviolet range that is attributed to the huge excitonic effects arising from the unique electronic structure of h-BN. Thus, h-BN is shown to exhibit a giant negative birefringence that ranges from -0.7 in the visible to -2 in the deep ultraviolet close to the band gap. The electronic dielectric constants f…
Tbx1 regulates Vegfr3 and is required for lymphatic vessel development
2010
Defects in lymphangiogenesis are added to the broad clinical manifestations of DiGeorge syndrome, caused by deletion of the T box transcription factor Tbx1.
Microphthalmia, persistent hyperplastic hyaloid vasculature and lens anomalies following overexpression of VEGF-A188 from the αA-crystallin promoter
2007
Purpose During growth of the embryonic eye, dose- and site-specific expression of heparin-binding growth factors is critical for the formation of an appropriate vascular supply. Overexpression of vascular endothelial growth factor-A188 (VEGF-A188), a strongly heparin-binding, endothelial-specific mitogen, leads to severe disturbance of vascular and overall ocular morphology. This study aimed to evaluate the effects of VEGF-A188 overexpression on growth of ocular tissue components. Methods Stereological and immunohistochemical methods were employed to identify the vascular profiles, ocular tissue proportions, and cell types in VEGF-A188 transgenic mice and compare them with wild-type mice. R…
Comparative study assessing effects of sonic hedgehog and VEGF in a human co-culture model for bone vascularisation strategies.
2011
The morphogen sonic hedgehog (Shh) seems to mediate adult repair processes in bone regeneration and vascularisation. In this study we investigated the effects of Shh on co-cultures consisting of human primary osteoblasts and outgrowth endothelial cells in terms of angiogenic activation and vessel maturation in comparison to the treatment with the commonly used proangiogenic factor, VEGF. Both, stimulation with VEGF or Shh, leads to an increase in the formation of microvessel-like structures compared to untreated controls. In contrast to VEGF, proangiogenic effects by Shh could already be observed after 24 h of treatment. Nevertheless, after 14 days the angiogenic activity of OEC was compara…
Intravitreal dexamethasone implant versus anti-vascular endothelial growth factor therapy combined with cataract surgery in patients with diabetic ma…
2021
Objective: to compare outcomes of cataract surgery combined with either anti-Vascular Endothelial Growth Factor (anti-VEGF) therapy or dexamethasone implant (DEX) in patients with diabetic macular oedema (DMO). Methods: Pubmed and Embase databases were searched for studies reporting outcomes of diabetic cataract surgery combined with either anti-VEGF or DEX, with a follow-up ≥3 months. The primary outcome was the mean change in central macular thickness (CMT). Mean change in best corrected visual acuity (BCVA) was considered as a secondary outcome. The mean difference between baseline and post-treatment values (MD) with 95%-Confidence Interval (95%CI) was calculated and meta-analyses were p…