This paper presents the complete set of polarization angular coefficients
A
0−7
describing lepton angular distributions in
Z
boson decay, which were measured at the ATLAS experiment in proton–proton ...collisions with the energy √
s
= 8 TeV. Theoretical values for the difference
A
0
−
A
2
calculated in the fixed-order QCD perturbation theory O(α
s
2
), demonstrate significant deviation from the measured data, which indicates the necessity of taking into account higher order corrections. The evidence of nonzero coefficients
A
5,6,7
was obtained for the first time, in accordance with theoretical calculations in O(α
s
2
) approximation. Measurement of the polarization angular coefficients
A
i
is important for subsequent precision measurement of parameters of the electroweak model at the LHC, such as the sine of Weinberg electroweak mixing angle sin
2
θ
W
and the W boson mass.
Excellent electron and photon reconstruction and identification capability will be needed over a broad energy range for most physics studies with the ATLAS detector at the Large Hadron Collider ...(LHC). Events with electrons and photons in the final state are important signatures to rediscover many of the Standard Model (SM) processes (electroweak vector bosons, top quarks, etc.), to search for new physics beyond the SM (new resonances at TeV scale, SUSY, etc.), to discover of Higgs boson (H→4e, H→γγ) and to understand of detector performance and its calibration. This paper describes the overall ATLAS detector performance for the reconstruction and identification of photons and electrons over a wide range of transverse energies, spanning from a few GeV to 5TeV.
Samples of monoalkyl and mixed-alkyl phosphine oxides of the hexyl–octyl series were synthesized previously by the Grignard method. Here, the group extraction of rare-earth metals contained ...simultaneously in their nitrate solutions has been studied using then-synthesized alkyl phosphine oxides. Extraction isotherms for the recovery of the total of lanthanides, scandium, and thorium from nitrate solutions have been obtained. Trihexyl phosphine oxide (THPO) exhibits the highest efficiency under these conditions. Trioctyl phosphine oxide (TOPO) exhibits the best selectivity to heavy-group lanthanides, which makes it useful for the recovery of the heavy-group lanthanide fraction. In addition, scandium and thorium were extracted completely, which in turn indicates the usefulness of phosphine oxides for their extraction. The separation factors have been determined for the entire lanthanides series.
Despite a persistent interest in verb processing, data on the neural underpinnings of verb retrieval are fragmentary. The present study is the first to analyze the contributions of both grey and ...white matter damage affecting verb retrieval through action naming in stroke. We used voxel-based lesion-symptom mapping (VLSM) with an action naming task in 40 left-hemisphere stroke patients. Within the grey matter, we revealed the critical involvement of the left precentral and inferior frontal gyri, insula, and parts of basal ganglia. An overlay of white matter tract probability masks on the VLSM lesion map revealed involvement of left-hemisphere long and short association tracts with terminations in the frontal areas; and several projection tracts. The involvement of these structures is interpreted in the light of existing picture naming models, semantic control processes, and the embodiment cognition framework. Our results stress the importance of both cortico-cortical and cortico-subcortical networks of language processing.
•Damage to left frontal areas; insula, and basal ganglia affects action naming.•Action naming relies upon frontal regions involved in word retrieval.•Action naming recruits regions involved in semantic control and motor processing.•Cortico-subcortical networks are critically involved in action naming.
Purpose. Development of a mathematical model of gear mesh which takes into account flexibility of a pinion support for studying the influence of lateral vibrations on gear dynamics as a whole. ...Methodology. The calculation model is designed using lumped-parameters method. The research on dynamics of the system is performed by methods of the theory of oscillations of two degree of freedom systems. Using the approximate method of theory of oscillations and algebra, vibrational amplitude of the system is defined. The results of numerical integration of dynamic equations are compared to the experimental data. Findings. State- of-the-art review on gear mesh models taking into account coupling effect of pinion torsional and lateral vibrations is performed. Based on the lumped-parameters method, an analytical model for calculating dynamics of gear mesh with flexible support is developed. The amplitude-frequency response of open gearing of a tumbling mill MSHRGU 4500 × 6000 is studies taking into account flexibility of a pinion shaft and bearing parts. It is shown that torsional vibrations of a pinion and lateral vibrations of a power unit have a coupling effect. The models of highly loade gearing give values of natural frequencies with a significant error. A range of possible force resonance in a power unit of tumbling mill open gearing is defined. Causes of excessive vibroactivity of mechanical systems of drives of certain mills and increasing vibroactivity when in operation are established. It is shown that amplification of vibroactivity of a tumbling mill power unit due to intermittent action of forces with gearing frequency is improbable. Rational techniques of reducing vibroactivity of existing mills due to lubrication and increasing hardness of working face of gear teeth are defined. Originality. Methods for defining resonance range of gear mesh which consider a coupling effect of pinion torsional vibrations and pinion shaft lateral vibrations are developed. Practical value. The range of possible force resonance in a power unit of tumbling mill MSHRGU 4500 x 6000 open gearing is defined.
Development of a design procedure of tooth bending durability upon incomplete tooth contact by a finite element method and its application for research of a stress state of tumbling mill open ...gearing. Calculation of the stress state is carried out with the finite element method. At the first stage the design model is formed. Further the construction and discretization of gearing geometrical model is done taking into account an axis misalignment angle. Displacements and stress in a tooth gearing upon incomplete tooth contact are calculated. Received distribution diagrams of displacements and stress are used for calculation of tooth bending stress. The article is devoted to the development of a design procedure of tooth bending durability taking into account gearing errors. The current state of the issue of tooth bending durability calculation upon incomplete tooth contact is investigated. The factors having a significant impact on a gearing error are defined. It is shown that the greatest impact on tooth gearing durability has an inclination angle of teeth in the plane of teeth contact. The estimation of the value of total inclination angle of teeth of tumbling mill MHIPTY 4500 × 6000 is given. The design model for calculating the tooth bending durability upon incomplete tooth contact with the finite element method is proved. Comparison of the results of calculation by the developed technique and by the engineering of ISO 6336-1:2006, 6336-3:2006 is made. It is shown that the existing engineering technique does not consider the features of large-sized tooth gearings stress state technique enough. The correction factors which allowing adapting an engineering technique for calculating tooth bending durability upon incomplete tooth contact are calculated. Significant influence of the central plate on tooth bending durability is established. It is established that upon incomplete tooth contact the load is distributed linearly along the theoretical line of the contact. The algorithm of a design procedure of tooth bending durability upon incomplete tooth contact with the finite element method is developed. The quantitative estimation of tooth bending durability of tumbling mill MHIPTY 4500x6000 open gearing is received.
This paper aims the development of the calculation technique of gear wheels tooth pair stiffness in one-pair gearing by the finite elements method and its application for an estimation of tumbling ...mills open tooth gearings stiffness. The calculation of stress state was carried out by the finite elements method. At the first stage the analytical model of a gearing was formed. Based on the key geometrical parameters and drawings the three-dimensional geometrical model of the tooth gearing was designed. The physical properties of the constructional materials were set. The geometrical model split into finite elements. The current situation in the field of the tooth gearings stiffness calculation was investigated. The special attention was paid to shortcomings of the existing standards with reference to the large-sized tooth gearings. The authors sowed the advantages of the finite elements method use for calculation of the tooth gearing elements strain state. The algorithm and a calculation technique of the tooth gearings stiffness by means of the finite elements method was presented.
Мета. Створення математично'1 модел1 важконавантажено'1 зубчасто'1 передач! İ3 самовстановлювальною приводною шестернею, а також визначення динамшного навантаження на зубчасту передачу внаслщок ...процесу встановлення шестерш. Методика. Розрахункова схема й ршняння выносного руху самовстановлювально'1 приводно! шестерш складен! за допомогою методы динамши твердого тша. Аналгтичш вирази для визначення часу самовстановлення шестерш, швидкосл при згткненш й коефшденту динамшного навантаження отримаш шляхом штегрування звичайного диференщального ршняння. Для визначен- ня коефщшнта динамiки використанi методи лшшно! теорй' коливань. Результати. Дослоджено сучасний стан питання щодо конструкци', а також математичного моделювання самовстановлювально! шестернi. 1з використанням методiв динамоки твердого тола складено рiвняння водносного руху рухомо! частини шестернi. Показано, що за допомогою висунутих гiпотез рух шестернi можна звести до обертання навколо миттево! осi. Дослоджено вплив геометричних i динамочних параметрiв приводу барабанного млина на динамшш завантаження у водкрито!' зубчасто! передачi. Отриманi залежносто швидкостi встановлення шестернi вод кута перекосу зубчасто! передачi та шерцшних параметрiв шестернi. За допомогою отриманих залежностей обчисленi час i швидкость установления шестернi водкрито!' зубчасто! передачi барабанного млина МШЦ 5,5 х 6,5. Показано, що в реальному дщпазот значень кута перекосу й параметра шестерш час !! встановлення на колька порядков менше часу перезачеплення зубiв. За наявностi змiнно!' складово! кута перекосу шестерня буде постшно здiйснювати в!дносний рух з ударами, i, у залежносто вод поточного значення кута перекосу, динамочне навантаження на зубчасту передачу може бути значним. Показано, що при встановленш ефективносто застосування самовстановлювально! шестерно необходно враховувати можливе збольшення динамочних навантажень. Обчислено коефшдент динамоки та коефшдент навантаження для номшального значення кута перекосу водкрито!' зубчасто! передачо барабанного млина МШЦ 5,5 х 6,5. Наукова новизна. Розроблена математична модель динамоки самовстановлювально! зубчасто! передачо приводу високо навантажених машин. Проведена колькосна оцонка коефшдента внутрошнього динамочного навантаження водкрито! зубчасто! передачо барабанного млина МШЦ 5,5 х 6,5. Практична значимать. Створена методика визначення динамочно! складово! навантаження на зубчасту передачу зо самовстановлювальною приводною шестернею.
Purpose. Development of a mathematical model of a heavy loaded gear transmission with a self-aligning drive gear; evaluation of the dynamic load on the gear transmission in the gear alignment ...process. Methodology. The calculation schematic and equations of the relative motion of the self-aligning drive gear are formed using the methods of rigid body dynamics. Analytical expressions for the gear self-alignment time, collision velocity during the alignment and dynamic load factor are obtained by integrating an ordinary differential equation. Methods of the linear theory for oscillations are used to determine the dynamic factor. Findings. The article investigates the state-of-art design and mathematical models of the self-aligning gear. An equation for the relative motion of the moving part of the gear has been formed using the methods of rigid body dynamics. It is shown that by using the proposed hypotheses, the movement of the gear can be reduced to rotation about the instantaneous axis. The influence of geometric and dynamic parameters of the ball mill drive on dynamic loads in the open gear transmission is investigated. The gear alignment speed dependences on the tooth mesh misalignment angle in the gear transmission and the inertial parameters of the gear have been obtained. The obtained dependencies were used to calculate the time and speed of the gear alignment in the open gear transmission of the ball mill 5.5 6.5 (central discharge ball mill). It is shown that in the real range of mesh misalignment angles and gear parameters, the time of the gear alignment is several orders of magnitude less than the time of teeth re-engagement. In the presence of the variable component of the mesh misalignment angle, the gear will constantly make a relative motion with strikes; depending on the current value of the mesh misalignment angle, the dynamic load on the gear transmission can be significant. It is shown that when assessing the efficacy of self-aligning gears, it is necessary to take into account a possible increase in dynamic loads. The dynamic factor and the load factor are calculated for the nominal value of the mesh misalignment angle in the open gear transmission of 5.5 6.5 ball mills. Originality. A mathematical model of the dynamics of a self-aligning gear transmission in heavy duty machine drives has been developed. A quantitative assessment of internal dynamic load factor in an open gear transmission of 5.5 6.5 ball mills has been carried out. Practical value. A method for determining the dynamic component of the load on a gear transmission containing a self-aligning drive gear has been developed.
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