The influence of resistant force equations and coupling system on long train dynamics simulations

In the simulation of the longitudinal dynamics of long trains, the modeling of the resistant forces and of the coupling system are two essential aspects. The modeling of the resistant forces directly affects the speed reached by each vehicle as well as the in-train forces. A literature review witnesses different laws for the calculation of both ordinary and accidental resistances. One of the objectives of this paper is to evaluate from the numerical point of view the influence of the resistant forces modeling strategy on the simulation outputs, i.e., on the speeds and in-train forces, by comparing different laws for propulsion and curving resistances. For what concerns the connection between the vehicles of the train, it is well known that the connection system is of utmost importance for the safety and running stability of the train. In this paper, the two existing coupling systems, i.e., the European buffer-hook system and the coupler used outside the European continent are first described, both in terms of operation and modelling techniques, and then they are compared on the same simulation scenario. All the simulations are performed on the first scenario of the International benchmark of the longitudinal train dynamic simulators, using the LTDPoliTO code developed by the railway research team from Politecnico di Torino

A 2000 Year-Old Cold Case: the Violent Death of a Roman Mariner Between Archaeology and Forensic Anthropology.

During archaeological excavation of the Roman port of Pisa in 1999, two skeletons came to light, laden down by a Roman ship, sunk and partly preserved, probably caused by a disastrous flood in the River Auser. Skeletons belonging to an adult male and a small dog, resembling the present Dachshund breed, were recovered. The canine rested on he man's left upper limb at the forearm level. This 2000 year-old cold case has been investigated using physical and forensic anthropological techniques which allowed us to define the biological profile of this subject: including the sex, age, height and skeletal pathology. The taphonomic analysis of bones and the context as a possible crime scene let us understand the decomposition and death dynamics revealing the causes of the partial dismemberment. The case presented is an example the physical anthropology as a discipline useful for the analysis of skeleton human remains, and as a useful tool in the reconstruction of ancient events and bio-archaeological data in synergy with forensic sciences

Rho-kinase inhibition blunts renal vasoconstriction induced by distinct signaling pathways in vivo

In addition to intracellular calcium, which activates myosin light chain (MLC) kinase, MLC phosphorylation and hence contraction is importantly regulated by MLC phosphatase (MLCP). Recent evidence suggests that distinct signaling cascades of vasoactive hormones interact with the Rho/Rho kinase (ROK) pathway, affecting the activity of MLCP. The present study measured the impact of ROK inhibition on vascular F-actin distribution and on vasoconstriction induced by activation/inhibition of distinct signaling pathways in vivo in the microcirculation of the split hydronephrotic rat kidney. Local application of the ROK inhibitors Y-27632 or HA-1077 induced marked dilation of pre- and postglomerular vessels. Activation of phospholipase C with the endothelin ET B agonist IRL 1620, inhibition of soluble guanylyl cyclase with 1H-[1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one (ODQ), or inhibition of adenylyl cyclase with the adenosine A1 agonist N6-cyclopentyladenosine (CPA) reduced glomerular blood flow (GBF) by about 50% through vasoconstriction at different vascular levels. ROK inhibition with Y-27632 or HA-1077, but not protein kinase C inhibition with Ro 31-8220, blunted ET B-induced vasoconstriction. Furthermore, the reduction of GBF and of vascular diameters in response to ODQ or CPA were abolished by pretreatment with Y-27632. ROK inhibitors prevented constriction of preglomerular vessels and of efferent arterioles with equal effectiveness. Confocal microscopy demonstrated that Y-27632 did not change F-actin content and distribution in renal vessels. The results suggest that ROK inhibition might be considered as a potent treatment of renal vasoconstriction, because it interferes with constriction induced by distinct signaling pathways in renal vessels without affecting F-actin structure

Spatial multiplexing in near field MIMO channels with reconfigurable intelligent surfaces

We consider a multiple-input multiple-output (MIMO) channel in the presence of a reconfigurable intelligent surface (RIS). Specifically, our focus is on analysing the spatial multiplexing gains in line-of-sight and low-scattering MIMO channels in the near field. We prove that the channel capacity is achieved by diagonalising the end-to-end transmitter-RIS-receiver channel, and applying the water-filling power allocation to the ordered product of the singular values of the transmitter-RIS and RIS-receiver channels. The obtained capacity-achieving solution requires an RIS with a non-diagonal matrix of reflection coefficients. Under the assumption of nearly-passive RIS, that is, no power amplification is needed at the RIS, the water-filling power allocation is necessary only at the transmitter. We refer to this design of RIS as a linear, nearly-passive, reconfigurable electromagnetic object (EMO). In addition, we introduce a closed-form and low-complexity design for RIS, whose matrix of reflection coefficients is diagonal with unit-modulus entries. The reflection coefficients are given by the product of two focusing functions: one steering the RIS-aided signal towards the mid-point of the MIMO transmitter and one steering the RIS-aided signal towards the mid-point of the MIMO receiver. We prove that this solution is exact in line-of-sight channels under the paraxial setup. With the aid of extensive numerical simulations in line-of-sight (free-space) channels, we show that the proposed approach offers performance (rate and degrees of freedom) close to that obtained by numerically solving non-convex optimization problems at a high computational complexity. Also, we show that it provides performance close to that achieved by the EMO (non-diagonal RIS) in most of the considered case studies

A proposal of classification for machine-learning vibration-based damage identification methods

Recent advances in computing power and sensing technology led to a significant evolution of Structural Health Monitoring (SHM) techniques, transforming SHM into a “Big Data” problem. The use of data-driven approaches for damage identification purposes, specifically Machine Learning (ML) methods, has gained popularity. ML can help at various levels of the SHM process: to pre-and post-process input data, extract damage sensitive features, and operate pattern recognition in measured data and output valuable information for damage identification. In this paper, the role of ML in SHM applications is discussed together with a new scheme for classifying ML applications in SHM, especially focusing on vibration-based monitoring, given its consolidated theoretical base. Finally, the implications of the application of these methods to historic structures are discussed, with a brief account of existing case studies. The proposed classification is exemplified using the most recent studies available in the literature on cultural heritage structures.- (undefined

Particle and light fragment emission in peripheral heavy ion collisions at Fermi energies

A systematic investigation of the average multiplicities of light charged particles and intermediate mass fragments emitted in peripheral and semiperipheral collisions is presented as a function of the beam energy, violence of the collision and mass of the system. The data have been collected with the "Fiasco" setup in the reactions 93Nb+93Nb at 17, 23, 30, 38AMeV and 116Sn+116Sn at 30, 38AMeV. The midvelocity emission has been separated from the emission of the projectile-like fragment. This last component appears to be compatible with an evaporation from an equilibrated source at normal density, as described by the statistical code Gemini at the appropriate excitation energy. On the contrary, the midvelocity emission presents remarkable differences for what concerns both the dependence of the multiplicities on the energy deposited in the midvelocity region and the isotopic composition of the emitted light charged particles.Comment: 18 pages, 17 figures, Revtex

Mortality and Morbidity Following Endovascular Repair of Abdominal Aortic Aneurysms: Analysis of Two Single Centre Experiences

AbstractObjective to show how differences in anatomical and physiological risk factors can affect the outcome of endovascular repair of AAA by describing the experience of two centres with different selection policies. Methods one hundred and thirty-five patients (group I) were treated at Queen's Medical Centre (Nottingham, U.K.) using 101 in-house made and 34 manufactured stent-grafts. Median diameter, length and angulation of the proximal aneurysm neck were 26 mm, 27 mm, 40°, respectively. Seventy-six patients had ischaemic heart disease, 47 had left ventricular failure, median forced expiratory volume in one second (FEV1) was 83%, median creatinine was 100 μmol/l and median age was 72 years. Fifty patients (group II) were treated at Timone Hospital (Marseilles, France) using seven in-house made and 43 manufactured stent-grafts. Median diameter, length and angulation of the proximal aneurysm neck were 25 mm, 34 mm, 33°, respectively. Thirteen patients had ischaemic heart disease, two had left ventricular failure, median forced expiratory volume in one second was 101%, median creatinine was 108 μmol/l and mean age was 72 years. Results anatomical characteristics of the proximal neck were significantly worse in group I (p=0.02 for the three variables). Cardiac comorbidities were more frequent and mean FEV1 was lower in group I (p<0.0001 and p=0.001, respectively. Median aneurysm diameter was significantly greater in group I (65 mm) than in group II (53 mm) (p<0.001). Postoperative mortality was 9% and 0% in groups I and II respectively (p=0.03). The incidence of technical complications (groin wound complications and side branches endoleaks being excluded) was 20% and 0% in groups I and II, respectively (p=0.0006). Conclusion postoperative mortality and technical complication rates were significantly greater in group I than in group II, readily explained by poorer general condition and worse anatomical characteristics of the proximal neck in group I