Novel considerations are presented on the physics, apparatus and accelerator designs for a future, luminous, energy frontier electron-hadron (
eh
) scattering experiment at the LHC in the thirties ...for which key physics topics and their relation to the hadron-hadron HL-LHC physics programme are discussed. Demands are derived set by these physics topics on the design of the LHeC detector, a corresponding update of which is described. Optimisations on the accelerator design, especially the interaction region (IR), are presented. Initial accelerator considerations indicate that a common IR is possible to be built which alternately could serve
eh
and
hh
collisions while other experiments would stay on
hh
in either condition. A forward-backward symmetrised option of the LHeC detector is sketched which would permit extending the LHeC physics programme to also include aspects of hadron-hadron physics. The vision of a joint
eh
and
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physics experiment is shown to open new prospects for solving fundamental problems of high energy heavy-ion physics including the partonic structure of nuclei and the emergence of hydrodynamics in quantum field theory while the genuine TeV scale DIS physics is of unprecedented rank.
A conceptual design is presented of a novel energy-recovering linac (ERL) facility for the development and application of the energy recovery technique to linear electron accelerators in the ...multi-turn, large current and large energy regime. The main characteristics of the powerful energy recovery linac experiment facility (PERLE) are derived from the design of the Large Hadron electron Collider, an electron beam upgrade under study for the LHC, for which it would be the key demonstrator. PERLE is thus projected as a facility to investigate efficient, high current (HC) (>10 mA) ERL operation with three re-circulation passages through newly designed SCRF cavities, at 801.58 MHz frequency, and following deceleration over another three re-circulations. In its fully equipped configuration, PERLE provides an electron beam of approximately 1 GeV energy. A physics programme possibly associated with PERLE is sketched, consisting of high precision elastic electron-proton scattering experiments, as well as photo-nuclear reactions of unprecedented intensities with up to 30 MeV photon beam energy as may be obtained using Fabry-Perot cavities. The facility has further applications as a general technology test bed that can investigate and validate novel superconducting magnets (beam induced quench tests) and superconducting RF structures (structure tests with HC beams, beam loading and transients). Besides a chapter on operation aspects, the report contains detailed considerations on the choices for the SCRF structure, optics and lattice design, solutions for arc magnets, source and injector and on further essential components. A suitable configuration derived from the here presented design concept may next be moved forward to a technical design and possibly be built by an international collaboration which is being established.
Antimonite glasses Sb2O3−PbO−ZnO/ZnS doped with ErCl3 within the range of 0.25–1.0 mol% were prepared and investigated by means of transmission, photoluminescence excitation and photoluminescence ...(PL) spectroscopy. In the studied glasses, the wavelength of 522 nm was found to be the most suitable for PL excitation of doped-in Er3+ ions in both the NIR and VIS spectral ranges. The PL spectra excited by wavelengths at 522 and/or 514.5 nm were measured at room and low temperatures (4 K) in the wavelength range of 400–1700 nm. Low-temperature PL spectroscopy allowed us to observe both the broad luminescence of the host glass centred at around 1050 nm and the narrow emissions caused by Er3+ ions. Special attention was given to the wavelengths where the broad-band luminescence of the host overlaps with 4f–4f transitions within Er3+ ions. A broad PL band of the host glass was observed together with a superimposed narrow emission band at 985 nm (4I11/2 → 4I15/2) and a narrow absorption dip at about 970 nm (4I15/2 → 4I11/2). This absorption dip is a direct experimental evidence of energy transfer from the electronic structure of the host glass to 4f states of doped-in Er3+ ions. The strongest PL band at 1530 nm, representing transition from the lowest excited manifold 4I13/2 to the ground state manifold 4I15/2 was measured at 300 K and 4 K. The broadening at elevated temperature occurs primarily in the high energy part of the spectrum due to thermal excitation of electrons within the 4I13/2 manifold.
•The 522 nm is suitable for excitation of both – the host glass and Er3+ ions.•Broad-band luminescence of the host glass was observed at low temperature.•Narrow emission bands correspond to 4f–4f transitions of Er3+ ions.•Observed narrow absorption dip correlates with the up-transition of Er3+.•Observed dip is a direct evidence of energy transfer from host glass to Er3+ ions.
The aim of this work was to investigate the effects of Impedance Therapy (IT) in the treatment of degenerative disc disease (DDD) by confirming the presence of the "disc grow-up" (DGU) phenomenon.
...The set consisted of 55 patients with DDD with the average age of 51.3 years divided into two groups - the experimental group and the control group. The experimental group consisted of 29 patients with the average age of 56.7 years. The control group consisted of 26 patients with the average age of 45.8 years.
In the experimental group of patients with DDD, who received IT, the DGU phenomenon with a success rate of 76 % was observed, with the average increase in the volume of the intervertebral disc of 31 % (p < 0.000). In the control group of patients receiving the standard electrotherapy, the DGU phenomenon was not proven - the DDD progressed normally with the mean volume reduction of 15 % (p < 0.000).
Degenerative disc disease, as a disease of modern civilization, is treatable. It can be concluded that the theory that degenerative disc changes are irreversible was disproven by the impact of impedance therapy (Tab. 5, Ref. 14).
Abstract
Structural health monitoring based on detecting strain enables further exploitation of the lightweight potential of aircraft structures. Since carbon fibres (CF) can be easily integrated ...into aircraft structures made of fibre-reinforced plastics (FRP), their use in sensor applications has become subject of research. One of many novel approaches is the use of cracked CF for strain detection. During loading and unloading, the fibre cracks are opening and closing respectively, resulting in substantial changes in the electric resistance of the CF. The high dependence of the electric resistance on the mechanical strain enables spatially resolved strain sensing along the CF based on the electric time domain reflectometry (ETDR) principle. However, due to high inhomogeneity of the used pitch-based CF and the resulting electric properties, the ETDR-signal is degraded largely by impedance mismatch along the transmission line, which limits the measuring length of a spatially resolved sensor. In this contribution, a concept for a spatially resolved CF-based strain sensor is described, outlining the challenges that need to be addressed. One approach for the extension of the measuring length is lowering the base resistivity of the used CF, which is discussed in detail. In order to achieve a low base resistivity while maintaining the characteristic of opening and closing fibre cracks, copper-coated CF are investigated. The copper-coated pitch-based CF are integrated into test specimens consisting of a composite material and are subjected to tensile loading. Simultaneously to the deflection, the electrical resistance is measured. Consequently, the sensitivity to strain of the CF is determined and discussed.
•The results of the benchmarking activity on wall condensation are reported.•The work was performed in the frame of SARNET.•General modelling techniques for condensation are discussed.•Results of ...University of Pisa and of other benchmark participants are discussed.•The lesson learned is drawn.
The prediction of condensation in the presence of noncondensable gases has received continuing attention in the frame of the Severe Accident Research Network of Excellence, both in the first (2004–2008) and in the second (2009–2013) EC integrated projects. Among the different reasons for considering so relevant this basic phenomenon, coped with by classical treatments dated in the first decades of the last century, there is the interest for developing updated CFD models for reactor containment analysis, requiring validating at a different level the available modelling techniques. In the frame of SARNET, benchmarking activities were undertaken taking advantage of the work performed at different institutions in setting up and developing models for steam condensation in conditions of interest for nuclear reactor containment.
Four steps were performed in the activity, involving: (1) an idealized problem freely inspired at the actual conditions occurring in an experimental facility, CONAN, installed at the University of Pisa; (2) a first comparison with experimental data purposely collected by the CONAN facility; (3) a second comparison with data available from experimental campaigns performed in the same apparatus before the inclusion of the activities in SARNET; (4) a third exercise involving data obtained at lower mixture velocity than in previous campaigns, aimed at providing conditions closer to those addressed in reactor containment analyses. The last step of the benchmarking activity required to change the configuration of the experimental apparatus to achieve the lower flow rates involved in the new test specifications.
The four benchmarking steps received the interest of a number of participants (more or less in the order of ten in each phase), who applied their models to the proposed blind exercises, receiving by the University of Pisa, as the hosting organization, comparisons with the reference data. Since the same geometry and relatively similar conditions were addressed in the four steps, though considering different operating conditions, a gradual improvement of the quality of results was observed with respect to the first applications. The activity revealed to be fruitful in providing the needed awareness about the capabilities of condensation models, at least in the simple configuration involved by the benchmark exercises.
The paper presents a unique extension and application of the dynamic mechanical analysis (DMA) technique for the determination of heterogeneous mechanical material properties. Their values as well as ...their spatial distribution are major interest when analysing properties of post-damage materials. The proposed procedure incorporates longer than typical beam-shaped test samples enclosing the zone with locally varied material properties. The mechanical properties are estimated for the extended sample at defined positions while the sample is iteratively shifted along its axis. The procedure was successfully validated in various tests incorporating standardised and extended samples.
The preliminary investigations regarding the application of the proposed procedure were conducted on composite specimens with heterogeneous distribution of material properties introduced by impact load. The results show, on the one hand, a monotonic relation between the storage modulus and the damage extent. On the other hand, a non-monotonic relation between the loss modulus and damage severity has been observed.
•Optical gap found at around 3.1 eV and its compositional tendency was deduced.•Emission spectra are overwhelmed by narrow 4f–4f emission bands of Er3+.•Fine structure of emission bands at 980 and ...1530nm measured at 300 and 4K.•Schematic energy diagram of Stark levels for 3 lowest manifolds of Er3+ is proposed.•A nature of temperature broadening of 4f–4f PL bands was discussed.
Bulk samples of Er-doped zinc–sodium–antimonite glasses have been investigated by transmission and photoluminescence (PL) spectroscopy. Two series of compositions, (Sb2O3)90−x(Na2O)10(ZnO)x and (Sb2O3)80−x(Na2O)20(ZnO)x, doped with 0.25mol% Er2O3, have been chosen for this study. Transmission spectra exhibit sharp absorption bands centred at 450, 489, 521, 545, 652, 795, 975 and 1530nm, which correspond to absorption of Er3+ ions and they are attributed to the optical transitions from the ground state 4I15/2 to the excited states 4F5/2, 4F7/2, 2H11/2, 4S3/2, 4F9/2, 4I9/2, 4I11/2 and 4I13/2, respectively. The optical gap has been found to vary from 3.09 to 3.15eV with a tendency to decrease at higher Na2O and/or ZnO contents. Four extrinsic bands due to OH−, Si–O, CO2, and (CO3)2− carbonate group vibrations have been identified in the infrared region. Emission spectra are overwhelmed by narrow 4f–4f emission bands. Fine structure of emission bands at 980 and 1530nm, corresponding to radiative transitions from two lowest excited states of Er3+ ions to the ground state manifold have been investigated at room temperature and at 4K. A schematic energy diagram of Stark levels splitting for the three lowest manifolds 4I11/2, 4I13/2 and 4I15/2 has been deduced and the nature of temperature broadening of 4f–4f PL bands has been discussed.
Temperature and frequency dependencies of DC and AC conductivities, dielectric response, static permittivity, optical absorption edge, infrared absorption spectrum, density, and temperatures of glass ...transition and crystallization for lithium molybdenum–antimonite glasses, (80−x)Sb2O3–20Li2O–xMoO3, where x=0–40, are measured and discussed. The DC conductivity increases with increasing concentration of MoO3. At 150°C, it ranges from 5×10−11S/m up to 3×10−8S/m. Polaron hopping between Mo5+ and Mo6+ ions contributes, probably, to the DC conductivity. Ionic conductivity by Li+ ions is also present. The conduction activation energy monotonously decreases from 1.15eV, at x=5, down to 0.91eV, at x=40. In all glasses with x>0, the conduction activation energy is close to a half of the indirect allowed optical gap. The pre-exponential factor, σ0, goes through a sharp maximum close to the composition (x=20) with both the highest glass transition temperature and the largest thermal stability range. The frequency dependence of the AC conductivity is composed of three components — the DC conductivity and two AC components. For x=35 and 40, the activation energy of electrical relaxation is equal to 0.954±0.008eV and the pre-exponential factor of relaxation times is equal to (4±1)10−14s. The static relative permittivity ranges from 17.4 to 23.0. Strong extrinsic absorption bands in infrared region originate from hydroxyl ions, CO2 impurities, and silicon–oxygen vibrations. The UV–visible indirect allowed absorption edge shifts from 2.6eV to 2.1eV with increasing MoO3 content. With increasing MoO3 content the glasses darken, from a light yellow color, at x=0, to a deep brown color, at x=40.
•The DC conductivity increases with increasing concentration of MoO3.•The conduction activation energy monotonously decreases from 1.15eV to 0.91eV.•The static relative permittivity ranges from 17.4 to 23.0.•The UV–visible indirect allowed absorption edge shifts from 2.6eV to 2.1eV with increasing MoO3 content.
Electrical and dielectric properties of ternary glasses in the Sb
2
O
3
–PbCl
2
–AgCl system were investigated across a broad temperature and frequency range. The studied glass system is interesting ...since it possesses a high ionic conductivity. The (Sb
2
O
3
)
x
–(PbCl
2
)
100 –
y
–
x
–(AgCl)
y
glasses were prepared by melt-quenching method from high purity components. Different batches of these glasses were investigated with varying molar content of both Sb
2
O
3
(45 ≤
x
≤ 70 mol %) and AgCl (5 ≤
y
≤ 25 mol %). The colour of the prepared chloro-antimonite glasses varies between yellow and brown. The glass transition temperature (
T
g
) decreases with increasing AgCl concentrations. DC and AC electrical conductivities and complex electrical modulus were measured across a temperature range from room temperature up to 200°C and across a frequency range between 0.2 and 10
5
Hz. The dependence of DC conductivity on temperature follows the so-called Arrhenius-like equation. The DC conductivity at constant temperature significantly increases with increasing AgCl or PbCl
2
content. It was found that the activation energy of conduction process decreases with the substitution of PbCl
2
by AgCl from 1 eV down to 0.56 eV for (Sb
2
O
3
)
50
-(PbCl
2
)
45
–(AgCl)
5
and (Sb
2
O
3
)
50
–(PbCl
2
)
25
–(AgCl)
25
, respectively. The influence of the composition on the AC conductivity of the investigated glasses is also discussed.
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