The Standard Model from LHC to future colliders

This review summarizes the results of the activities which have taken place in 2014 within the Standard Model Working Group of the “What Next” Workshop organized by INFN, Italy. We present a framework, general questions, and some indications of possible answers on the main issue for Standard Model physics in the LHC era and in view of possible future accelerators.     

Ab initio quantum mechanics of a cluster of SiH4 and two H2 molecules, together with its dimer and trimer

Recent experimental work by Strobel et al. [T.A. Strobel, M. Somayazulu, R.J. Hemley, Phys. Rev. Lett. 103 (2009) 065701] on a molecular solid subjected to high pressures has motivated the present study. We first investigate a molecular cluster containing one silane molecule plus two H₂ molecules, by ab initio quantum mechanics. Geometrical and electronic structures for the ground state of such a cluster are thereby proposed. The di-cluster is next examined, and the coming together of two H₂ molecules is predicted. Finally, the tri-cluster is studied and important aspects of the di-cluster bonding are found to remain largely intact.     

Modelling and solving the perfect edge domination problem

Optimization Letters - A formulation is proposed for the perfect edge domination problem and some exact algorithms based on it are designed and tested. So far, perfect edge domination has been...     

Optimization of a dielectric barrier discharge actuator by stationary and non-stationary measurements of the induced flow velocity: application to airflow control

Several studies have shown that a surface dielectric barrier discharge (DBD) may be used as an electrohydrodynamic (EHD) actuator in order to control airflows. In this paper, a parametric study has been performed in order to increase the velocity of the ionic wind induced by such actuators. The results show that an optimization of geometrical and electrical parameters allows us to obtain a time-averaged ionic wind velocity up to 8 m/s at 0.5 mm from the wall. Moreover, non-stationary measurements of the induced wind have been performed with synchronized records of current and voltage signals. These experiments show that the DBD actuator seems to generate a pulsed velocity at the same frequency than the applied high voltage.     

Control of an axisymmetric subsonic air jet by plasma actuator

It is known that surface non-thermal plasma actuators have proved their efficiency for aerodynamics flow control. In this study, a dielectric barrier discharge (DBD) is mounted on the diffuser of an axisymmetric turbulent air jet in order to control the flow separation along a 12-degree diffuser bevel. The momentum created by the actuator is applied to separate an air flow naturally attached to the diffuser for air flow velocity up to 40 m s⁻¹. Laser sheet visualizations and LDV measurements are achieved to characterize the unforced and forced air jet. The flow separation, the induced velocity fluctuations, the jet mixing improvement and vectoring are investigated. The main results of this study demonstrate that DBD actuators are suitable to fully detach the air flow along the bevel for a velocity of 20 m s⁻¹ and that a jet vectoring between 13.5° and 5.5° could be achieved for velocity ranging between 20 and 40 m s⁻¹. Considerations about a potential improvement of the jet mixing are also introduced and the laser sheet visualization attests that induced flow perturbations are highly 3D.     

Orientational Order in Nematic and Smectic A Phases of Three Closely Related Compounds 4 4-di-n-Heptylazobenzene 4 4-di-n-Heptyl- and 4 4-di-n-Octylazoxybenzene

The orientational ordering in the three related compounds 4,4-di-n-heptyl-d₂-azobenzene-d, (HB-d₁₂), 4,4'-di-n-heptyl-d₂-azoxybenzene-d, (HAB-d₁₂) and 4,4-di-n-octyl-d₂-azoxybenzene-d₈ (OAB-d₁₂) has been monitored using deuteron N.M.R. spectroscopy. In these non-rigid molecules it is possible to obtain only the elements of local order matrices. For the aromatic rings these are found to be axially symmetric within the precision of our measurements. The temperature dependences of the local order parameters for the aromatic rings are compared with those predicted by McMillan's theory of smectic A phases.     

Nickel quantification in serum by a validated sector-field inductively coupled plasma mass spectrometry method: Assessment of tentative reference values for an Italian population

The daily exposure to Ni from food, industrial processes, jewellery and coins makes the determination of Ni in human serum an important way to monitor the health status in non-occupationally exposed subjects. To this end, a method based on sector-field inductively coupled plasma mass spectrometry was developed and validated. The limits of detection (LoD) and quantification (LoQ), sensitivity, linearity range, trueness, repeatability, within-laboratory reproducibility and robustness were the considered issues of the validation process. The uncertainty associated with the measurements was also calculated, according to the Eurachem/Citac Guide. The method LoD and LoQ were 0.03 and 0.09 ng mL(-1), linearity was over two order of magnitude, trueness was -3.57%, and the repeatability and reproducibility showed relative standard deviations equal to 4.56% and 6.52%, respectively. The relative expanded uncertainty was 21.8% at the Ni levels found in the general population. The tentative reference value for serum Ni was 0.466 +/- 0.160 ng mL(-1) with a related interval between 0.226 and 1.026 ng mL(-1).