Search results for "Axia"
showing 10 items of 638 documents
Ectopic hbox12 Expression Evoked by Histone Deacetylase Inhibition Disrupts Axial Specification of the Sea Urchin Embryo
2015
Dorsal/ventral patterning of the sea urchin embryo depends upon the establishment of a Nodal-expressing ventral organizer. Recently, we showed that spatial positioning of this organizer relies on the dorsal-specific transcription of the Hbox12 repressor. Building on these findings, we determined the influence of the epigenetic milieu on the expression of hbox12 and nodal genes. We find that Trichostatin-A, a potent and selective histone-deacetylases inhibitor, induces histone hyperacetylation in hbox12 chromatin, evoking broad ectopic expression of the gene. Transcription of nodal concomitantly drops, prejudicing dorsal/ventral polarity of the resulting larvae. Remarkably, impairing hbox12 …
KNOWN RESIDUAL STRESS SPECIMENS USING OPPOSED INDENTATION
2009
In order to test new theories for residual stress measurement or to test the effects of residual stress on fatigue, fracture, and stress corrosion cracking, a known stress test specimen was designed and then fabricated, modeled, and experimentally validated. To provide a unique biaxial stress state, a 60 mm diameter 10 mm thick disk of 316L stainless steel was plastically compressed through the thickness with an opposing 15 mm diameter hard steel indenters in the center of the disk. For validation, the stresses in the specimen were first mapped using time-of-flight neutron diffraction and Rietveld full pattern analysis. Next, the hoop stresses were mapped on a cross section of two disks usi…
Influence of correlations between stresses on calculated fatigue life of machine elements
1996
The correlation between components of the random stress tensor and its influence on the calculated fatigue life of machine elements were analysed. Three covariance matrices of components of biaxial stress state were considered. They were determined from measurements of strains in an element of a vibrating screen for aggregate, in the back wall of a bus, and in a welded element of excavator fittings. Calculations were made according to four criteria of multiaxial random fatigue. Cycles were counted with the rainflow method, and damage was cumulated with the Palmgren-Miner hypothesis. It was found that convariances of random stress state components strongly influence the calculated fatigue li…
Serviceability and Ultimate Safety Checks of SegmentalConcrete Bridges through N-M and M-V Interaction Domains
2015
In current engineering practice, safety checks on serviceability and determinations of ultimate limit states of segmental bridges built by cantilevering are generally performed, either considering separately the contributions of axial force N, bending moment M, and shear force V, or considering the interaction effects through approximate expressions supplied by building codes. During construction stages and service life, the interaction between internal forces can be of fundamental importance in establishing the actual degree of structural safety and, for this reason, a different philosophy for performing checks in segmental bridges is proposed in this paper, plotting N-M and M-V interactio…
A new bi-faced log periodic printed antenna
2005
In this paper, a new design of a broadband planar printed antenna based on the academic log periodic antenna is presented. The antenna consists of a series of printed dipoles, distributed on both faces of the substrate. Some configurations are explored, with a different number of printed dipoles. These are designed, simulated, fabricated, and measured. The calculated and measured return losses and radiation patterns are presented. The utility of the proposed antenna associated with its frequency bandwidth is better than 80%. The measured absolute gain is 6.5 dBi, and the front-to-back ratio is around 8 dB. The presented antenna should find wide applications in wireless communication systems…
Dual-band printed dipole antenna for Wi-Fi 802.11n applications
2010
A dual-band compact printed dipole antenna for Wi-Fi 802.11n applications in the 2.45 and 5.5 GHz bands is presented. The proposed antenna consists of two printed dipoles with the arms located onto both sides of the dielectric substrate and a bended stripline. This feed scheme makes easy the integration of the antenna with the electronic subsystem and avoids the radiation towards the device. For the design and optimisation, a specifically developed finite-difference time-domain based code is used. The antenna has then been fabricated, simulated and measured. The return losses highly match the Wi-Fi frequency specifications with a moderate gain (between 1 and 3 dBi) and efficiency better tha…
Load carrying capacity of RC compressed columns strengthened with steel angles and strips
2012
Abstract In this paper a comparison between the analytical expressions for the prediction of the load carrying capacity of strengthened reinforced concrete (RC) columns with steel angles and strips is made. Expressions examined consider: the strength contribution due to the confinement effects induced by transverse strips; the composite action due to steel angles and unconfined concrete core; the strength contribution due to the composite actions of angles and concrete core taking into account that steel angles are subjected to axial force and bending moment and concrete core is confined by transverse strips. Design rules given by recent codes for the design of the strengthened columns are …
Theoretical-Applicative Research on Design and Implementation of a Special Dynamometer
2013
The topic of he present paper is taken from the Automotive Systems Nurnberg, Sibiu. It refers to the product automatic gear box which equips a few FORD models, the specific part for which the research was developed being a auto screwing bolt for plastic which raises problems at the robotized screwing because of the poor knowledge of the accurate value of the axial force and the necessary torque.
Experimental Investigation of Stall and Surge in a Multistage Compressor
2016
Flow instability conditions, in particular during surge and stall phenomena, have always influenced the operational reliability of turbo-compressors and have attracted significant interest resulting in extensive literature. Nowadays, this subject is still one of the most investigated because of its high relevance on centrifugal and axial compressor operating flow range, performance and efficiency. Many researchers approach this important issue by developing numerical models, whereas others approach it through experimental studies specifically carried out in order to better comprehend this phenomenon. The aim of this paper is to experimentally analyze the stable and unstable operating condit…
Performance of two innovative stress sensors imbedded in mortar joints of new masonry elements
2021
Abstract Many historical cities enjoy the presence of masonry buildings with inestimable historical, artistic and cultural value. Old masonry buildings often suffer structural deficiencies, design faults and materials aging process. In recent years, many researchers focused their attention on the opportunities that structural health monitoring (SHM) can ensure for the health state of existing masonry structures, where damage can be difficult to be promptly predicted, pontentially causing abrupt collapses, with high risks for the community. This paper presents an experimental study on the effectiveness of two types of stress sensor for SHM of new masonry elements. Ceramic piezoelectric senso…