scholarly journals Measurement of multiplicities of charged hadrons, pions and kaons in DIS at COMPASS

2018 ◽  
Vol 177 ◽  
pp. 04007
Author(s):  
Nikolai Mitrofanov

Precise measurements of multiplicities of charged hadrons, pions and kaons in deep inelastic scattering were performed. The data were obtained by the COMPASS Collaboration by scattering 160 GeV muons off an isoscalar 6LiD target. The results were obtained in three-dimensional bins of the Bjorken scaling variable x, the relative virtual-photon energy y, and the fraction z of the virtual-photon energy carried by the produced hadron. A leading-order pQCD analysis was performed using the pion multiplicity results to extract quark fragmentation functions into pions. The results for the sum of the z-integrated multiplicities for pions and for kaons, differ from earlier results from the HERMES experiment. The results from the sum of the z-integrated K+ and K- multiplicities at high x point to a value of the non-strange quark fragmentation function larger than obtained by the earlier DSS fit.

1937 ◽  
Vol 4 (1) ◽  
pp. A1-A7 ◽  
Author(s):  
M. A. Biot

Abstract The elementary theory of the bending of a beam on an elastic foundation is based on the assumption that the beam is resting on a continuously distributed set of springs the stiffness of which is defined by a “modulus of the foundation” k. Very seldom, however, does it happen that the foundation is actually constituted this way. Generally, the foundation is an elastic continuum characterized by two elastic constants, a modulus of elasticity E, and a Poisson ratio ν. The problem of the bending of a beam resting on such a foundation has been approached already by various authors. The author attempts to give in this paper a more exact solution of one aspect of this problem, i.e., the case of an infinite beam under a concentrated load. A notable difference exists between the results obtained from the assumptions of a two-dimensional foundation and of a three-dimensional foundation. Bending-moment and deflection curves for the two-dimensional case are shown in Figs. 4 and 5. A value of the modulus k is given for both cases by which the elementary theory can be used and leads to results which are fairly acceptable. These values depend on the stiffness of the beam and on the elasticity of the foundation.


2018 ◽  
Vol 211 ◽  
pp. 04007
Author(s):  
Alexander Petrov ◽  
Semyon Shkundin

The establishment of dispatching and automatic control systems for mine ventilation is impossible without the availability of perfect air flow rate sensors. Existing anemometers (tachometer, heat) do not meet these requirements. The error of average in cross section velocity measurements with such sensors reaches 15-20, sometimes 30%. The reason - the speed measured at one point is interpreted as the average over the cross section. The reliability of the sensors is small, because they are exposed to the damaging effect of a dusty atmosphere. Stationary installed anemometers clutter cross section, which is not always allowed. Fermat’s variational principle is used for derivation of the formula for the time of propagation of a sonic signal between two set points A and B in a steady three-dimensional flow of a fluid or gas. It is shown that the fluid flow changes the time of signal reception by a value proportional to the flow rate independently of the velocity profile. The time difference in the reception of the signals from point B to point A and vice versa is proportional with a high accuracy to the flow rate. It is shown that the relative error of the formula does not exceed the square of the largest Mach number. This makes it possible to measure the flow rate of a fluid or gas with an arbitrary steady subsonic velocity field


Researchers know a little about time. If they could not find where time was, they could not study it. The objective of this study was to find where time was. Any numbers in three principal axes were used to be data. Galileo’s concept of the relationship among distance, speed, and time was used to find a position of a value of time in any number lines in a three-dimensional body. Mathematical derivative was used to prove the positions of the values of time. The investigation found that time is in all number lines including three principal axes. Also, the time equation can be used to calculate the exact position of any values of time in the line. The equation can be used to explain equations in science such as equations of Newton, Einstein, and Plank, and social science such as equations of consumption and saving in macroeconomics. If researchers use the time equation to explain N equations, then a time value can get at least N variables of N equations. The speed of calculation will increase. The equation will be used to open new characteristics about time and others because mathematicians use numbers to represent everything in nature


Quantum ◽  
2018 ◽  
Vol 2 ◽  
pp. 97 ◽  
Author(s):  
A. González-Tudela ◽  
J. I. Cirac

Quantum emitters coupled to structured photonic reservoirs experience unconventional individual and collective dynamics emerging from the interplay between dimensionality and non-trivial photon energy dispersions. In this work, we systematically study several paradigmatic three dimensional structured baths with qualitative differences in their bath spectral density. We discover non-Markovian individual and collective effects absent in simplified descriptions, such as perfect subradiant states or long-range anisotropic interactions. Furthermore, we show how to implement these models using only cold atoms in state-dependent optical lattices and show how this unconventional dynamics can be observed with these systems.


Author(s):  
Ben Gorte ◽  
Sisi Zlatanova

The paper presents a very straightforward and effective algorithm to convert a space partitioning, made up of polyhedral objects, into a 3D block of voxels, which is fully occupied, i.e. in which every voxel has a value. In addition to walls, floors, etc. there are 'air' voxels, which in turn may be distinguished as indoor and outdoor air. The method is a 3D extension of a 2D polygon-to-raster conversion algorithm. The input of the algorithm is a set of non-overlapping, closed polyhedra, which can be nested or touching. The air volume is not necessarily represented explicitly as a polyhedron (it can be treated as 'background', leading to the 'default' voxel value). The approach consists of two stages, the first being object (boundary) based, the second scan-line based. In addition to planar faces, other primitives, such as ellipsoids, can be accommodated in the first stage without affecting the second.


Author(s):  
Andrea Biscarini ◽  
Andrea Calandra ◽  
Samuele Contemori

A three-dimensional biomechanical model has been developed to understand and quantify the effect of the triceps brachii force during bench press exercises executed with different external loads, grip widths, and positions of the barbell relative to the shoulders at the beginning of the lift. The upper limbs, chest, and barbell were modeled as a closed three-dimensional articulated system. The elbow extension torque [Formula: see text] developed by the triceps brachii is transferred through the links of the closed chain, yielding a shoulder transverse-flexion torque [Formula: see text], shoulder adduction torque [Formula: see text], and shoulder internal-rotation torque [Formula: see text] proportional to [Formula: see text]. The proportionality factors [Formula: see text], [Formula: see text], and [Formula: see text] are independent of the load and displayed a considerable change during the lift: [Formula: see text] increased from 0.5 to 2, while [Formula: see text] and [Formula: see text] decreased progressively to zero, with a value at the beginning of the lift between 0.5 and 1 depending on the starting barbell position and grip width. Overall, [Formula: see text] considerably decreased the demand for shoulder transverse-flexion and adduction muscle-torque, slightly increased the demand for shoulder abduction muscle-torque in the final phase of the lift, and induced a shoulder internal-rotation torque that should be equilibrated by an opposite torque developed by the shoulder external rotators. With the results of this study, sport practitioners can manage the variants and kinematics of the bench press exercise to modulate the effect of the triceps brachii force on the mechanical output during different phases of the lift and planes of movement.


1992 ◽  
Vol 114 (2) ◽  
pp. 434-441 ◽  
Author(s):  
L. W. Swanson ◽  
G. C. Herdt

A mathematical model describing the evaporating meniscus in a capillary tube has been formulated incorporating the full three-dimensional Young–Laplace equation, Marangoni convection, London–van der Waals dispersion forces, and nonequilibrium interface conditions. The results showed that varying the dimensionless superheat had no apparent effect on the meniscus profile. However, varying the dispersion number produced a noticeable change in the meniscus profile, but only at the microscopic level near the tube wall. No change in the apparent contact angle was observed with changes in the dimensionless superheat or dispersion number. In all cases, the dimensionless mean curvature was asymptotic to a value equal to that for a hemispherical meniscus. The local interfacial mass flux and total mass transfer rate increased dramatically as the dispersion number was increased, suggesting that surface coatings can play an important role in improving or degrading capillary pumping. The model also predicted that the local capillary pressure remains constant and equal to 2σ/rc regardless of changes in the dimensionless superheat and dispersion number. It should be noted that the results in this study are theoretical in nature and require experimental verification.


2003 ◽  
Vol 797 ◽  
Author(s):  
Koichi Awazu ◽  
Makoto Fujimaki ◽  
Yoshimichi Ohki ◽  
Tetsuro Komatsubara

ABSTRACTWe have developed a nano-micro structure fabrication method in rutile TiO2 single crystal by use of swift heavy-ion irradiation. The area where ions heavier than Cl ion accelerated with MeV-order high energy were irradiated was well etched by hydrofluoric acid, by comparison etching was not observed in the pristine TiO2 single crystal. Noticed that the irradiated area could be etched to a depth at which the electronic stopping power of the ion decayed to a value of 6.2keV/nm. We also found that the value of the electronic stopping power was increased, eventually decreased against depth in TiO2 single crystal with, e.g. 84.5MeV Ca ion. Using such a beam, inside of TiO2 single crystal was selectively etched with 20% hydrofluoric acid, while the top surface of TiO2 single crystal subjected to irradiation was not etched. Roughness of the new surface created in the single crystal was within 7nm with the atomic forth microscopy measurement.


Author(s):  
A. Abd El-Sabor Mohamed ◽  
Saleh Abo-Elfadl ◽  
Abd El-Moneim M. Nassib

The in-cylinder airflow motion is an important factor that severely affects combustion efficiency and emissions in diesel engines. It is greatly affected by the inlet port and valve geometries. A diesel engine cylinder with a helical–spiral inlet port is used in this study. An ordinary inlet valve and shrouded inlet valve having different shroud and orientation angles are used to study the shroud effect on the swirl and tumble motion inside the engine cylinder. Four shroud angles of 90 deg, 120 deg, 150 deg, and 180 deg are used. With each shroud angle, four orientation angles of 0 deg, 30 deg, 60 deg, and 90 deg are also used. Three-dimensional simulation model using the shear stress transport (SST) k–ω model is used for simulating air flow through the inlet port, inlet valve, and engine cylinder during both the intake and compression strokes. The results showed that increasing the valve shroud angle increases the swirl, and the maximum increase occurs at a valve shroud angle of 180 deg and orientation angle of 0 deg with a value of 80% with respect to the ordinary valve. But it decreases the volumetric efficiency, and the maximum decrement occurs at valve shroud of 180 deg and orientation angle of 90 deg with a value of 5.98%. Variations of the shroud and orientation angles have very small effect on the tumble inside the engine cylinder.


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