2,743 research outputs found
Effect of welding sequence in angular distortion on butt joint GMAW process
Over time, the industrial use of the welding process has grown in significance and is now one of the primary methods for joining metallic parts. During the welding process, metallurgical and structural modifications occur close to the welded joint. The thermal stresses and geometric distortions are undesirable, and they are a challenge to accurately forecast. Laboratory tests were conducted utilizing the GMAW method on S235JR steel as the base material with the goal of examining the impact of the welding sequence on angular distortion in butt joints when comparing three different welding sequences. Equipment that can determine coordinates in the operational space with metrological accuracy was used to measure distortions. As a result of metrological and statistical analyses, it was found that the sequence factor is shown to substantially influence the final distortions and that the symmetrical method results in less distortions followed by a one-step method.Financial support was provided by Portugal’s national funding FCT/MCTES (PIDDAC)
to Centro de Investigação de Montanha (CIMO) (UIDB/00690/2020 and UIDP/00690/2020) and
SusTEC (LA/P/0007/2020).info:eu-repo/semantics/publishedVersio
The neutron time-of-flight facility n-TOF at CERN: Phase II
Neutron-induced reactions are studied at the neutron time-of-flight facility n-TOF at CERN. The facility uses 6∼ns wide pulses of 20 GeV/c protons impinging on a lead spallation target. The large neutron energy range and the high instantaneous neutron flux combined with high resolution are among the key characteristics of the facility. After a first phase of data taking during the period 2001-2004, the facility has been refurbished with an upgraded spallation target and cooling system for a second phase of data taking which started in 2009. Since 2010, the experimental area at 185 m where the neutron beam arrives, has been modified into a worksector of type A, allowing the extension of the physics program to include neutron-induced reactions on radioactive isotopes
Heats of Mixing Using an Isothermal Titration Calorimeter: Associated Thermal Effects
The correct determination of the energy generated or absorbed in the sample cell of an Isothermal Titration Calorimeter (ITC) requires a thorough analysis of the calorimetric signal. This means the identification and quantification of any thermal effect inherent to the working method. In this work, it is carried out a review on several thermal effects, studied by us in previous work, and which appear when an ITC is used for measuring the heats of mixing of liquids in a continuous mode. These effects are due to: (i) the difference between the temperature of the injected liquid and the temperature of the mixture during the mixing process, (ii) the increase of the liquid volume located in the mixing cell and (iii) the stirring velocity. Besides, methods for the identification and quantification of the mentioned effects are suggested
The Construction of Stations and Tunnels by Slurry Trecnch, Method in the Madrid Metro Extension
Recently a new Extension of the Madrid Subway (Spain) is carried out (1995-2003). In 8 years more of 105 Km of tunnels are builded by several procedures: Traditional non-mechanized excavation, precast linings by E.P.B machines, cut and cover system, etc. In this paper the basic criteria adopted for the design of tunnels and stations built with the cut and cover method (reinforced concrete continuous and discontinuous walls) are analysed. Initially, to this purpose the geotechnical properties of the Madrid ground are reached, in order to establish a group of unified desion geotechnical parameters. The hypotheses made for the numerical analysis of in situ walls are shown (calculation model, water pressures, etc), together with the installed instrumentation and the obtained results
Assessment of hormonal parameters in long-term karate Practitioners
Introduction: Karate is a Japanese martial art which is widely practiced in the Western world as a form of self-defense, as well as a discipline to achieve physical and mental balance.However, little is known with respect to its specific psychobiological effects, particularly in relation to the influence that karate may exert on the endocrine system. Thus, in the present study we analyzed the effects of regular karate practice on several hormonal parameters.
Methods: 27 healthy volunteer subjects participated in the study, of whom 15 were allocated to the experimental group, and 12 were assigned to the control group. Experimental
subjects were karate players with a minimum of 3 years of practice in this discipline. Blood samples for the quantification of hormonal parameters (TSH, T3, T4, PTH, ACTH, cortisol, and DHEA) were taken in both groups. To compare the means of the control and experimental group, a t-test for independent groups was performed in each dependent variable.
Results: Significant differences between the experimental and control group were found in T3, T4, and cortisol, with karate players showing lower blood levels of these hormones than
control.
Conclusions: These findings reveal that long-term karate practice is associated to a significant endocrine modulation, which suggests interesting psychobiological implications,
and lends itself to potential clinical considerations. Further research is needed to properly assess the scope of the peculiar hormonal profile displayed by advanced karate practitioners.Universidad de Málaga, Campus de Excelencia Internacional AndalucÃa Tec
Immune modulation after long-term karate practice
Introduction: Karate is a Japanese martial arts system which traces its roots back to China, and is nowadays widely popular both as a method of self-defense, as well as a discipline
with potential physical and psychological benefits. However, karate has been scarcely investigated from a psychobiological perspective, and its effects on the immune system remain virtually unknown. Therefore, we designed the present study with the aim of analyzing the effects of several years of regular karate practice on different immune parameters.
Methods: 27 healthy volunteer subjects participated in the study, 15 being allocated to the experimental group, and 12 to the control group. Experimental subjects were all karate players who had practiced this martial art for a minimum of three years. Blood samples for the quantification of immune parameters (leukocytes, neutrophils, monocytes, eosinophils, basophils, lymphocytes, IgG, IgA, IgM, IgE) were taken in both groups. As statistical analysis, a t-test for independent groups was performed in each dependent variable.
Results: Compared to the control group, karate practitioners exhibited a significantly higher number of leukocytes, monocytes, and lymphocytes, as well as greater serum concentrations of IgG and IgM.
Conclusions: Our findings show that long-term karate practice is related to a broad modulation of immune parameters, including leukocytes counts as well as immunoglobulin
concentrations. This peculiar immunomodulatory profile, apart from its psychobiological relevance, may have noteworthy clinical implications. Further investigation would be necessary to fully elucidate the influence that long-term karate training can exert on the immune system.Universidad de Málaga, Campus de Excelencia Internacional AndalucÃa Tec
A new approach for the construction of historical databases—NoSQL Document-oriented databases: the example of AtlantoCracies
This article proposes, and justifies, the use of the Document-oriented databases as a flexible, easy to use, and powerful digital
tool in the field of historical research. First, the reasons that have made relational databases the predominant instrument among
historians are studied, while detailing the problems involved in their use. Next, the way in which historians have tried to face these
problems by using other digital tools is explained, as well as the limitations that such use entails. Through a case study—that of
European aristocratic networks in early modern times—it is shown, however, that Document-oriented databases, present notable
advantages and have greater explanatory power for the historian’s work. Thanks to their flexibility, they are better adapted to the
often-unpredictable nature of historical sources without diminishing their ease of use or their analytical potential.Junta de AndalucÃa UPO-1264973Junta de AndalucÃa HUM 100
Factores multiplicadores del rÃo Tunjuelo
(Eng) The most important sources of pollution in urban rivers are the sewage system discharges, disturbing
the quality and behavior patterns of water resources. The Tunjuelo River is one of the most polluted and
important stream from Bogota city, receiving numerous wastewater discharges. Therefore, its sanitation
has become one of the main objectives of the environmental authority. However, in order to take action
is necessary to understand the water quality behavior specifically loads patterns. This article shows the
results of the load multiplier factors for total suspended solids (TSS) and biochemical oxygen demand
(BOD), these factors were calculated to understand the behavior of wastewater discharges and at different
points on the river. Finally, each discharge has its own characteristics that affect differently the behavior
of the river downstream, resulting in a distortion in the flow pattern in most of the sampled points.(Spa) Las fuentes puntuales de contaminación más importantes en los rÃos urbanos son las descargas directas
del sistema de alcantarillado, además estas afectan la calidad y el patrón de comportamiento de las fuentes
hÃdricas. El rÃo Tunjuelo es una de las corrientes de agua más importante y contaminada de la ciudad de
Bogotá, pues recibe una gran cantidad de vertimientos. Por lo anterior su saneamiento se ha convertido
en uno de los principales objetivos de la autoridad ambiental, sin embargo, para poder tomar acciones es
necesario entender su comportamiento. En el presente artÃculo se muestran los resultados de los factores
multiplicadores de carga para sólidos suspendidos totales (SST) y demanda bioquÃmica de oxÃgeno
(DBO), puesto que estos son el instrumento económico para el cálculo de la tasa retributiva en Colombia,
los cuales fueron calculados para entender el comportamiento de las descargas de aguas residuales y el
de diferentes puntos sobre el rÃo. Finalmente, se puede observar que cada descarga tiene caracterÃsticas
propias que afectan de diferente manera el comportamiento del rÃo aguas abajo, generando como resultado
una distorsión en el patrón de flujo de los factores multiplicadores en la mayorÃa de puntos muestreados
'Stable' QPOs and Black Hole Properties from Diskoseismology
We compare our calculations of the frequencies of the fundamental g, c, and
p--modes of relativistic thin accretion disks with recent observations of high
frequency QPOs in X-ray binaries with black hole candidates. These classes of
modes encompass all adiabatic perturbations of such disks. The frequencies of
these modes depend mainly on only the mass and angular momentum of the black
hole; their weak dependence on disk luminosity is also explicitly indicated.
Identifying the recently discovered relatively stable QPO pairs with the
fundamental g and c modes provides a determination of the mass and angular
momentum of the black hole. For GRO J1655-40, M=5.9\pm 1.0 M_\sun,
, in agreement with spectroscopic mass
determinations. For GRS 1915+105, M=42.4\pm 7.0 M_\sun, or (less favored) M=18.2\pm 3.1 M_\sun, . We briefly address the issues of the amplitude, frequency width,
and energy dependence of these QPOs.Comment: 10 pages, 1 figure. Accepted for publication in Astrophysical Journal
Letter
Two-twistor particle models and free massive higher spin fields
FÃsica Teórica, Atómica y Óptic
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