► All-particle energy spectrum of cosmic rays between knee and ankle is not a single power law. ► Just above 1016eV the spectrum exhibits a hardening. ► Around 8×1016eV there is a knee-like feature ...in the spectrum.
The energy spectrum of cosmic rays between 1016eV and 1018eV, derived from measurements of the shower size (total number of charged particles) and the total muon number of extensive air showers by the KASCADE-Grande experiment, is described. The resulting all-particle energy spectrum exhibits strong hints for a hardening of the spectrum at approximately 2·1016eV and a significant steepening at ≈8·1016eV. These observations challenge the view that the spectrum is a single power law between knee and ankle. Possible scenarios generating such features are discussed in terms of astrophysical processes that may explain the transition region from galactic to extragalactic origin of cosmic rays.
The KASCADE-Grande experiment Apel, W.D.; Arteaga, J.C.; Badea, A.F. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2010, Volume:
620, Issue:
2
Journal Article
Peer reviewed
Open access
KASCADE-Grande is the enlargement of the KASCADE extensive air shower detector, realized to expand the cosmic ray studies from the previous 10
14–10
17
eV primary energy range to 10
18
eV. This is ...performed by extending the area covered by the KASCADE electromagnetic array from 200×200 to 700×700
m
2 by means of 37 scintillator detector stations of 10
m
2 area each. This new array is named Grande and provides measurements of the all-charged particle component of extensive air showers (
N
ch
), while the original KASCADE array particularly provides information on the muon content
(
N
μ
)
. Additional dense compact detector set-ups being sensitive to energetic hadrons and muons are used for data consistency checks and calibration purposes. The performance of the Grande array and its integration into the entire experimental complex is discussed. It is demonstrated that the overall observable resolutions are adequate to meet the physical requirements of the measurements, i.e. primary energy spectrum and elemental composition studies in the primary cosmic ray energy range of 10
16–10
18
eV.
The paper aims at studying the effects of the inherent fractional constitutive law of viscoelastic bearings used as devices for tuned mass dampers. First, the proper constitutive law of the ...viscoelastic supports is determined by the local constitutive law. Then, the characteristic force–displacement relationship at the top of the bearing is found. Taking advantage of the whole bearing constitutive laws, the tuning of the mass damper is proposed by defining the damped fractional frequency, which is analogous to the classical damped frequency. The effectiveness of the optimal tuning procedure is validated by a numerical application on a system subjected to a Gaussian white noise.
Schwertmannite is a poorly crystalline nanometric iron sulfate oxyhydroxide. This mineral shows a structural variability under different environments. Because of that, the determination of its ...structure and, consequently, of its physical–chemical properties is quite challenging. This article presents a detailed structural investigation of the structure of schwertmannite conducted under different approaches: X‐ray absorption spectroscopy, Rietveld refinement, and a combined reverse Monte Carlo and Debye function analysis of the whole nanoparticle structure. The schwertmannite model presented here is, to the auhors' knowledge, the most complete model so far reported.
A single‐particle structural model of schwertmannite is proposed from a combined multi‐technique approach, using a novel reverse Monte Carlo/Debye scattering equation parallel code.
•A simplified pre-design formulation for TLCD passive control systems subjected to random loads is introduced.•Numerical results obtained with the proposed formulation are validated through an ...experimental campaign.•Experimental tests have been carried out on three different configurations of TLCD device.•Experimental results are very close to both classical nonlinear formulation and proposed simplified formulation one.•Proposed approach reliability has been proved in time and frequency domain, as well as in terms of response statistics.
The passive control of vibrations has received in recent years a great deal of attention from researchers. Several types of devices have been proposed in order to reduce the dynamic responses of different kinds of structural systems. Among them, the Tuned Liquid Column Damper (TLCD) has proved to be very effective in reducing vibration of structures. However, since the equations governing the TLCD controlled systems response is nonlinear, the calibration of TLCD parameters is time consuming and not convenient to perform in a pre-design phase. In this context, it has recently been introduced by the authors a formula that allows to choose the optimal parameters of TLCD in a direct and fast way. This ready-to-use and straightforward proposed formulation has been verified by comparison with the numerical Monte Carlo simulation based on the nonlinear complete system. In this paper numerical results obtained with the proposed formulation are validated through an experimental campaign on a small scale SDOF shear-type model, built in the Experimental Dynamic Laboratory of University of Palermo, and equipped with a TLCD excited at the base with random noises through a shaking table.
Schwannoma is a peripheral nerve tumor that arises from the neural sheath, generally solitary and benign. Retroperitoneal location is rare, less than 6%, and often asymptomatic until the tumor ...reaches a large size and causes compressive symptoms. Schwannoma is difficult to diagnose by conventional imaging features alone, and so diagnosis is commonly confirmed with surgical resection. Endoscopic ultrasound (EUS) fine-needle aspiration (FNA) is useful for the preoperative diagnosis and the following treatment plan, although the diagnostic accuracy rate is rather low. EUS fine needle biopsy (FNB), with improved needle designs, has shown increasingly better diagnostic accuracy even in extrapancreatic solid lesions. We report a case of a retroperitoneal schwannoma successfully diagnosed before surgery by EUS-guided FNB.
In a previous study of the L1157 B1 shocked cavity, a comparison between NH3(10–00) and H2O(110–101) transitions showed a striking difference in the profiles, with H2O emitting at definitely higher ...velocities. This behaviour was explained as a result of the high-temperature gas-phase chemistry occurring in the post-shock gas in the B1 cavity of this outflow. If the differences in behaviour between ammonia and water are indeed a consequence of the high gas temperatures reached during the passage of a shock, then one should find such differences to be ubiquitous among chemically rich outflows. In order to determine whether the difference in profiles observed between NH3 and H2O is unique to L1157 or a common characteristic of chemically rich outflows, we have performed Herschel-HIFI observations of the NH3(10–00) line at 572.5 GHz in a sample of eight bright low-mass outflow spots already observed in the H2O(110–101) line within the Water In Star-forming regions with Herschel Key Programme. We detected the ammonia emission at high velocities at most of the outflows positions. In all cases, the water emission reaches higher velocities than NH3, proving that this behaviour is not exclusive of the L1157-B1 position. Comparisons with a gas–grain chemical and shock model confirms, for this larger sample, that the behaviour of ammonia is determined principally by the temperature of the gas.
Fluid damper devices inserted in buildings or bridges are commonly used as energy sinks for seismic protection. In the response analysis of structures with filled damper devices the main problem ...exists in the strong nonlinear behavior of such equipment, as a consequence the differential equation of motion remains nonlinear and the response spectrum analysis still cannot be applied. In this note, by using the concept of power spectral density function coherent with the elastic response spectrum and by using the statistical linearization technique, expressions for finding the equivalent linear damping have been found. Comparisons with results obtained by Monte Carlo simulations confirm that for the kind of nonlinearity induced by fluid dampers the statistical linearization technique gives satisfactory results in terms of second order moments, as well as in terms of absolute maximum peak response. The latter is evaluated by the semiempirical formulation of Vanmarcke.
Ferrihydrite is a generic term for various poorly ordered Fe(III) oxyhydroxides which are naturally occurring as nanocrystals and are believed to constitute the ferric core of ferritine, the main ...iron storage protein in biological systems. Unlike other iron oxides, the exact structure and composition of ferrihydrite is still a matter of debate. In this work, we have prepared and characterized the two main forms of ferrihydrite referred to as 2-lines and 6-lines, on the basis of the number of reflections observed in the (X-ray) diffraction pattern. Thermal and textural properties have been studied; structural characterization has been performed by X-ray diffraction, transmission electron microscopy and X-ray absorption spectroscopy (EXAFS and XANES). The structure of the two forms results to be quite similar. The study of the magnetic properties indicates that the small differences between the 2-lines and 6-lines ferrihydrite samples are mainly caused by the different weight of the magnetic spins located on the particle surface, related to the different nanoparticles mean size.
Liver surgery is considered a curative treatment for hepatocellular carcinoma (HCC) but the importance of resection margin width remains controversial. The aim of this study is to clarify the role of ...5-10 mm surgical margin width on post-operative recurrence and overall survival after resection.
We analyzed recurrence rate and overall survival rate of 72 patients who underwent curative hepatic resection for HCC smaller than 5 cm with 5-10 mm surgical margin width between January 2005 and December 2014.
The mean follow-up period was 36 months. Among the seventy-two patients, thirty-one (31/72; 43%) developed recurrence but only eleven (11/31; 15.3%) along the resection margin. The disease-free survival was 77.2%, 50%, 41.4% at 1, 3 and 5 years respectively, and the overall survival was 89.9%, 78.8%, 60% at 1, 3 and 5 years respectively.
5-10 mm surgical resection margin for HCC smaller than 5 cm seems to be safe as a wider surgical margin because does not increase the risk of marginal recurrence and does not decrease overall survival rate. Further prospective and randomized studies are required to definitively clarify the importance of surgical margin width in hepatic resection for HCC.
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