Strongly coupled lattice gauge theory with dynamical fermion mass generation in three dimensions

We investigate the critical behaviour of a three-dimensional lattice \chiU\phi_3 model in the chiral limit. The model consists of a staggered fermion field, a U(1) gauge field (with coupling parameter $\beta$) and a complex scalar field (with hopping parameter $\kappa$). Two different methods are used: 1) fits of the chiral condensate and the mass of the neutral unconfined composite fermion to an equation of state and 2) finite size scaling investigations of the Lee-Yang zeros of the partition function in the complex fermion mass plane. For strong gauge coupling ($\beta < 1$) the critical exponents for the chiral phase transition are determined. We find strong indications that the chiral phase transition is in one universality class in this $\beta$ interval: that of the three-dimensional Gross-Neveu model with two fermions. Thus the continuum limit of the \chiU\phi_3 model defines here a nonperturbatively renormalizable gauge theory with dynamical mass generation. At weak gauge coupling and small $\kappa$, we explore a region in which the mass in the neutral fermion channel is large but the chiral condensate on finite lattices very small. If it does not vanish in the infinite volume limit, then a continuum limit with massive unconfined fermion might be possible in this region, too.Comment: 27 pages, 16 figure

Rocking isolation of a typical bridge pier on spread foundation

It has been observed that after some earthquakes a number of structures resting on spread footings responded to seismic excitation by rocking on their foundation and in some cases this enabled them to avoid failure. Through application to a standard bridge supported by direct foundations, this paper discusses the major differences in response when foundation uplift is taken into consideration. Special focus is given on the modifications of rocking response under biaxial and tri-axial excitation with respect to uniaxial excitation. It is found that inelastic rocking has a significant isolation effect. It is also shown that this effect increases under biaxial excitation while it is less sensitive to the vertical component of the earthquake. Finally, parametric analyses show that the isolation effect of foundation rocking increases as the size of the footing and the yield strength of the underlying soil decreases

Engineering reconnaissance following the August 24, 2016 M6.0 Central Italy earthquake

An earthquake with a moment magnitude reported as 6.0 from INGV (Istituto Nazionale di Geofisica e Vulcanologia); occurred at 03:36 AM (local time) on 24 August 2016 in the central part of Italy. The epicenter was located at the borders of the Lazio, Abruzzi, Marche and Umbria regions, about 2.5 km north-east of the village of Accumoli and about 100 km from Rome. The hypocentral depth was about 8 km (INGV). We summarize preliminary findings of the Italy-US GEER (Geotechnical Extreme Events Reconnaissance) team, on damage distribution, causative faults, earthquake-induced landslides and rockfalls, building and bridge performance, and ground motion characterization. Our reconnaissance team used multidisciplinary approaches, combining expertise in geology, seismology, geomatics, geotechnical engineering, and structural engineering. Our approach was to combine traditional reconnaissance activities of on-ground recording and mapping of field conditions, with advanced imaging and damage detection routines enabled by state-of-the-art geomatics technology. We anticipate that results from this study, will be useful for future post-earthquake reconnaissance efforts, and improved emergency respons

Structural effects of the chelating rings in trans-[NiPh2P(Se)NPPh2-Se,P2] and trans-[NiPh2P(Se)NPPh2-Se,PPh2P(Se)N (H)PPh2-Se,P]Cl·CH2Cl2·H 2O complexes

The reaction of the monooxidised imidodiphosphinate ligand Ph2P(Se)NHPPh2 with NiCl2·6H2O in the presence of tBuOK afforded [NiPh2P(Se)NPPh2-Se,P2] (1), which was characterized by UV-Vis, IR and NMR spectroscopies. X-ray crystallographic studies on a single crystal of 1 revealed the trans Ni(Se,P)2 arrangement in the solid state, showing a bis-chelating type of coordination. The diamagnetic 31P NMR peaks of 1 in CDCl3 were interpreted as &quot;deceptive&quot; triplets, due to the conservation of the square-planar trans-isomer of 1 in solution. The structure of 1 exhibits a center of symmetry, with the two five-membered Ni-Se-P-N-P rings being equivalent. The higher electronegativity of Se compared to P is considered as the likely cause of the P-N bond length differences observed in the chelating rings of 1. During the reaction between NiCl2·6H2O and the ligand Ph2P(Se)N(S)-CH(CH3)PhPPh2, single crystals were obtained, the analysis of which by X-ray crystallography showed the formation of trans-[NiPh2P(Se)NPPh2-Se,PPh2P(Se)N (H)PPh2-Se,P]Cl·CH2Cl2·H 2O (2). Complex 2 contains one Ni-Se-P-N(H)-P and one Ni-Se-P-N-P ring. Structural comparison between 1 and 2 makes possible to establish structural effects due to the protonation/deprotonation of the rings at their N atom. © 2009 Elsevier Ltd. All rights reserved

An Efficient Disinfectant, Composite Material {SLS@[Zn3(CitH)2]} as Ingredient for Development of Sterilized and Non Infectious Contact Lens

The [Zn3(CitH)2] (1) (CitH4= citric acid), was dispersed in sodium lauryl sulphate (SLS) to form the micelle of SLS@[Zn3(CitH)2] (2). This material 2 was incorporated in hydrogel made by hydroxyethyl-methacrylate (HEMA), an ingredient of contact lenses, toward the formation of pHEMA@(SLS@[Zn3(CitH)2]) (3). Samples of 1 and 2 were characterized by UV-Vis, 1H-NMR, FT-IR, FT-Raman, single crystal X-ray crystallography, X-ray fluorescence analysis, atomic absorption and TG/DTA/DSC. The antibacterial activity of 1–3 as well as of SLS against Gram-positive (Staphylococcus epidermidis (St. epidermidis) and Staphylococcus aureus (St. aureus)) and Gram-negative (Pseudomonas aeruginosa (PAO1), and Escherichia coli (E. coli)) bacteria was evaluated by the means of minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and inhibitory zone (IZ). 2 showed 10 to 20-fold higher activity than 1 against the bacteria tested. Moreover the 3 decreases the abundance of Gram-positive microbes up to 30% (St. aureus) and up to 20% (PAO1) the Gram-negative ones. The noteworthy antimicrobial activity of the obtained composite 3 suggests an effective antimicrobial additive for infection-free contact lense

On the stability of colonnade structural systems under static and dynamic loading conditions

The structural behavior of colonnade structural systems subjected to static and dynamic loading is investigated to identify the main factors affecting the stability and to improve our understanding of their behaviour. In particular, the discrete element method of analysis is utilised to study the static and dynamic behaviour of a typical section of the two storey colonnade of the Forum in Pompeii. Static analysis indicated that the failure of colonnade structures occur at higher friction angles as the weight above the structure decreases and so a sudden collapse can occur when parts of the monument are disassembled. For the dynamic analysis, the mechanical behavior of the colonnade was investigated for both harmonic and real seismic excitations. For excitations with relatively low dominant frequencies, the primary response is rocking; as the excitation frequency increases, the response becomes more complicated demonstrating both sliding and rocking movements. It was also shown that the construction methods used in ancient times, such as multi-block segmented trabeations and solid block beam, have quite significant impact on the mechanical response of the structures under static and dynamic loading