130 research outputs found
Study of the slowing down of high energy proton shots through metals via a Monte Carlo simulation of the Fokker-Planck equation
The aim of this work is to analyze the diffusion and the slowing down of high energy proton shots through a target. Analyzing the phenomenon rigorously with the full transport equations, means tack ling many difficulties, most of which arise from the long range nature of the Coulomb interactions involving more than one particle simultaneously. The commonly used approach of neglecting the multi-body collisions, though correct for rarefied neutral gases, of ten leads to very poor approximations when charged particles moving through dense matter are considered. Here we present a Monte Carlo simulation of the Fokker-Planck equation where the multi-body collisions are taken into account. The model al lows the calculation of a point-wise distribution of energy and momentum transferred to the tar get
Dispersion Relation of Longitudinal Waves in Liquid He-4 in the Framework of Quantum Macroscopic Equations derived from Bohm's Potential
He-4 is known to become superfluid at very low temperatures. This effect is
now generally accepted to be connected with BEC (Bose-Einstein Condensation).
The dispersion relation of pressure waves in superfluid He-4 has been
determined at 1.1 {\deg}K by Yarnell et al., and exhibits a non monotonic
behavior - with a maximum and a minimum - usually explained in terms of
excitations called rotons, introduced by Landau. In the present work an attempt
is made to describe the phenomenon within the bohmian interpretation of QM. To
this end, the effects of the intermolecular potential, taken to be essentially
of the Lennard-Jones type modified to account for molecule finiteness, are
included as a Vlasov-type self-consistent field. A dispersion relation is
found, that is in quite good agreement with Yarnell's curve.
Keywords: Bohm potential; Intermolecular potential; Dispersion relation;
Superfluid He-4; First sound.
PACS: 05.30.Jp; 05.20.Dd; 03.75.Kk; 67.25.dtComment: 17 pages 3 figures (embedded
Competing verbal constructions with functional TAKE in Bulgarian
This paper discusses the preliminary results of an online acceptability
judgments questionnaire on some Bulgarian verbal periphrases featuring the
functional verb vzemam ‘take’. The study was conceived to fill a gap in the
literature about functional TAKE in Bulgarian, which has been known in
previous work since Sandfeld (1900) but is still rather scarce and unsystematic. Three TAKE+V2 constructions are identified: i) a Multiple Agreement
Construction featuring the connector da (TAKE daMAC); ii) a MAC featuring
ˇce (TAKE ˇceMAC); iii) Pseudo-Coordination (of the type TAKE + i ‘and’ +
V2). The participants are 157 native speakers (112 F, 45 M) with an age range
of 18-80 (M = 43.63; SD = 13.92). The results of the questionnaire confirm
the presence and the productivity of these constructions with functional TAKE
in present-day Bulgarian. Moreover, they show that these constructions all
share a monoclausal structure, but with some structural differences: V1 in the
TAKE MACs is mainly restricted to the past tense, and V2 only occurs in the
present, while in the iPseCo V1 and V2 share TAM features and can appear
both in the present and in the past. From a semantic point of view, TAKE
daMAC specializes for inchoativity, while TAKE ˇceMAC for mirativity. The
iPseCo seems to be able to convey both meanings, but it is least preferred than
the TAKE MACs
Spark plasma sintering of alumina/yttria-doped silicon carbide
AbstractSilicon carbide possesses exceptional mechanical and thermal properties, but its densification by conventional sintering is often very difficult. In the present work, silicon carbide was consolidated by spark plasma sintering in the presence of alumina and yttria. The results pointed out that the use of a single oxide does not enhance the sintering kinetics significantly, while the contemporaneous addition of both oxides has a beneficial effect on densification, with a relative density increase of about 10%. Interestingly, the oxide doping allows to double the room‐temperature flexural strength
Transient analysis of SIRIO using RELAP5/MOD3.3 system code
The main outcome of the present paper is the feasibility analysis of SIRIO (Sistema di rimozione della Potenza di decadimento per Reattori InnOvativi) facility with conditions based on those of its reference facility. The aim of SIRIO project is to study an innovative Decay Heat Removal System (DHRS) for liquid metal reactor and advanced Light Water Reactor (LWR). Such system must ensure passive control of the power removed from the primary system in abnormal condition, and must ensure reactor cooling in both short and long term. This study present numerical simulations developed with RELAP5/MOD3.3, of two operational procedures: the first one is a steady-state and the second one is a transient phase with decay heat generation. The thermal-hydraulic model, developed with RELAP5/MOD3.3, simulates the whole facility including lines, valves, water and gas tanks, and the Molten Salts (MS) gap. Since there is not experimental data, the present paper is a pre-test study based on SIRO facility design
The speed of reinfusion affects the vascular system during ozone major autohemotherapy
Ozone major autohemotherapy (O-MAHT) is a way of ozonetherapy administration consisting of drawing patient’s venous blood, mixing with oxygen/ozone, and reinfusing it into the vein. Some ozone therapists reported side effects during the O-MAHT, but the origin has not been described yet. We investigated the effect of blood drawing velocity during O-MAHT to see its effects on the vascular system and symptomatology. We administered O-MAHT to 11 subjects, and we interleaved fast and slow reinfusions. We monitored cerebral macrocirculation with transcranial Doppler (TCD) and tissue microcirculation with near-infrared spectroscopy (NIRS). Annoying symptoms appeared just during the fast reinfusion periods. NIRS and TCD parameters revealed vasoconstriction during fast reinfusion and improved metabolism during slow reinfusion. Overall, our investigation well discriminated fast from slow reinfusion velocity
Early prediction of the highest workload in incremental cardiopulmonary tests
Incremental tests are widely used in cardiopulmonary exercise testing, both in the clinical domain and in sport sciences. The highest workload (denoted Wpeak) reached in the test is key information for assessing the individual body response to the test and for analyzing possible cardiac failures and planning rehabilitation, and training sessions. Being physically very demanding, incremental tests can significantly increase the body stress on monitored individuals and may cause cardiopulmonary overload. This article presents a new approach to cardiopulmonary testing that addresses these drawbacks. During the test, our approach analyzes the individual body response to the exercise and predicts the Wpeak value that will be reached in the test and an evaluation of its accuracy. When the accuracy of the prediction becomes satisfactory, the test can be prematurely stopped, thus avoiding its entire execution. To predict Wpeak, we introduce a new index, the CardioPulmonary Efficiency Index (CPE), summarizing the cardiopulmonary response of the individual to the test. Our approach analyzes the CPE trend during the test, together with the characteristics of the individual, and predicts Wpeak. A K-nearest-neighbor-based classifier and an ANN-based classier are exploited for the prediction. The experimental evaluation showed that the Wpeak value can be predicted with a limited error from the first steps of the tes
Production of radioisotopes within a plasma focus device
In recent years, research conducted in the US and in Italy has demonstrated production of radioisotopes in plasma focus devices, and particularly, on what could be termed "endogenous" production, to wit, production within the plasma it self, as opposed to irradiation of tar gets. This technique relies on the formation of localized small plasma zones characterized by very high densities and fairly high temperatures. The conditions prevailing in these zones lead to high nuclear reaction rates, as pointed out in previous work by several authors. Further investigation of the cross sections involved has proven necessary to model the phenomena involved. In this paper, the present status of research in this field is re viewed, both with regards to cross section models and to experimental production of radio isotopes. Possible out comes and further development are discussed
Effects of oxygen ozone therapy on cardiac function in a patient with a prior myocardial infarction
Oxygen-ozone therapy has been piloted in Italy patients with ischemic heart disease or suffering from myocardial infarction since 1991. Over time, it has been observed that ozone exerts a significant anti-inflammatory and rheological activity: ozone activates the redox system, lowers the pro-inflammatory cytokines16β, TNFα, modulates the NF-KB system, reduces platelet aggregation, and stimulates the release of growth factors. It is because of these characteristics that oxygen-ozone therapy is used in the prevention and treatment of ischemic heart disease and for post-infarction rehabilitation. The case study – a critically ill patient aged 76 with acute myocardial infarction (AMI), suffering from ischemic heart disease and heart attacks, high blood pressure, renal failure, ischemic vascular pluri-infarct CNS disease, Parkinsonism, stroke, neurological bladder disease and debilitating inguinal hernia – after a year and a half of AMI with infusions of autologous blood treated with ozone (GAE), recovered the left ventricular ejection fraction from 33 to 50% and underwent a successful inguinal hernia operation. It appears evident that oxygen ozone therapy using GAE protect the hearts of patients suffering from ischemic heart disease, and is useful during the acute phase of infarctions, as well as for rehabilitating patients who have had an AMI with stenting
the rem observing software
The Rapid Eye Mount (REM) is a 60 cm robotic telescope located at La Silla, Chile. Its Observing Software (REMOS) is constituted by a set of distributed intercommunicating processes organized around a central manager. Together they grant the system safety, automatically schedule and perform observations with two simultaneous cameras of user-defined targets, and drive fast reaction to satellite alerts. Subsequent data reduction is left to pipelines managed by each camera
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