We report an improved measurement of the valence u and d quark distributions from the forward-backward asymmetry in the Drell-Yan process using 8.6 fb(-1) of data collected with the D0 detector in p (p) over bar collisions at root s = 1.96. This analysis provides the values of new structure parameters that are directly related to the valence up and down quark distributions in the proton. In other experimental results measuring the quark content of the proton, d quark contributions are mixed with those from other quark flavors. In this measurement, the u and d quark contributions are separately extracted by applying a factorization of the QCD and electroweak portions of the forward-backward asymmetry.

The ploughing forces (PFs) are one of the important parameters for calculating the tool life. They directly affect the stress on the tool flank face and are responsible for wear and tear conditions of the cutting tool as well. In this study we attempted to find the impact of cutting speed on PFs, that is, the relation between cutting speed and PFs. In this paper, the ploughing forces were estimated by a new comparison method in which forces at different point of contact areas are added (sum of forces) to get the PFs accurately. The accuracy of PFs estimated with this method will be better than previously used methods. This paper presents the measurement results of the PFs when turning stainless steel, structural steel and aluminum alloy materials. The results of experimental studies showed that an increase in cutting speed ranging from 50 to 200 m/min resulted in increase in PFs by 1.4–3.2 times when turning with different flank wears.

Currently, two methods are most often used to determine the ploughing forces: the extrapolation on zero uncut chip thickness and the comparison of total forces at different flank wears. These methods assume that the processes occurring on the front surface of the tool cause no effect on the processes transpiring on the rear surface. This study attempted to prove the connection between these processes, and both methods cannot be used to find the ploughing forces. The results showed that the increase in the uncut chip thickness causes the increase in the ploughing forces. This finding proves the connection between the processes occurring on the front and rear surfaces. To reveal the ploughing forces, we suggest using the third method, the comparison method of the total forces for different contact areas, which is based on the dependence of the processes on the rear surface on the processes on the front surface.

I discuss several novel and unexpected aspects of quantum chromodynamics. These include: (a) the nonperturbative origin of intrinsic strange, charm and bottom quarks in the nucleon at large x; the breakdown of pQCD factorization theorems due to the lensing effects of initialand final-state interactions; (b) important corrections to pQCD scaling for inclusive reactions due to processes in which hadrons are created at high transverse momentum directly in the hard processes and their relation to the baryon anomaly in high-centrality heavy-ion collisions; and (c) the nonuniversality of quark distributions in nuclei. I also discuss some novel theoretical perspectives in QCD: (a) lightfront holography – a relativistic color-confining first approximation to QCD based on the AdS/CFT correspondence principle; (b) the principle of maximum conformality – a method which determines the renormalization scale at finite order in perturbation theory yielding scheme independent results; (c) the replacement of quark and gluon vacuum condensates by “in-hadron condensates” and how this helps to resolves the conflict between QCD vacuum and the cosmological constant.

A new way of solving the spectral problem to describe electronic excitations is demonstrated for a hydrogen atom. The applied methodology is based formally on the idea of electronic excitation description without introducing boundary conditions to the eigenvalue problem for the square of the angular momentum operator. The eigenvalues of such an operator are considered as complex in general. As a result, the spectral problem for the Schrödinger equation becomes non-Hermitian with complex energy values. The imaginary part of the total energy helps to estimate the excitation lifetime within a unified scheme. The existence of the Stark shift of atomic energy levels and the collapse of the atomic spectra are confirmed.

We present a study of the normalized transverse momentum distribution of W bosons produced in p ¯ p collisions, using data corresponding to an integrated luminosity of 4 . 35 fb − 1 collected with the D0 detector at the Fermilab Tevatron collider at ffiffiffi s p ¼ 1 . 96 TeV. The measurement focuses on the transverse momentum region below 15 GeV, which is of special interest for electroweak precision measurements; it relies on the same detector calibration methods which were used for the precision measurement of the W boson mass. The measured distribution is compared to different QCD predictions and a procedure is given to allow the comparison of any further theoretical models to the D0 data.

Today, the study of the city’s sewerage network is an important part of the life of the city and the environment. Ensuring optimal living conditions not only for oneself, but also for other participants in the environment should be a priority for a person. Today we can face various problems that complicate the operation of the city sewer network and can cause detrimental effects on the environment. To prevent this impact on the environment, you first need to understand the cause of this impact, and then look for a solution. Wastewater is a pollutant of rivers, lakes and the water system in general. Wastewater is formed in connection with human activity, the appearance of rainwater, as well as under the influence of industrial enterprises. The purpose of the article is to develop the management of wastewater flows within the city sewer network to ensure the highest quality water clarification and minimize environmental harm.

When monitoring cutter wear during microcutting, it is necessary to consider the ploughing force of the tool flank face (PFs). The method of measurement differs based on the wear of the cutting tools and cannot be applied to determine PFs. When we cut brittle materials using a tool with wear there are significant fluctuations in the cutting forces due to the unstable chip formation, so the cutting forces cannot be measured. A new method for defining PFs when cutting brittle materials with the formation of discontinuous chips has been proposed in this study. The reliability of the new method has been confirmed by comparing PFs obtained with the help of different methods of cutting materials with the formation of continuous chips.

Recent results of the studies of exotic multiquark hadrons in the Fermilab D0 experiment are reported. These refer to the search and investigation of the $${{Z}_{c}}(3900)$$ state produced in semi-inclusive beauty-hadron decays and to the search for prompt $${{Z}_{c}}(3900)$$ production in $$p\bar {p}$$ collisions. Results of D0 searches for inclusive production of $${{P}_{c}}(4440)$$ and $${{P}_{c}}(4457)$$ pentaquark states are also presented.

This work is devoted to the investigation of virus quasi-species evolution and diversification due to mutations, competition for host cells, and cross-reactive immune responses. The model consists of a nonlocal reaction–diffusion equation for the virus density depending on the genotype considered to be a continuous variable and on time. This equation contains two integral terms corresponding to the nonlocal effects of virus interaction with host cells and with immune cells. In the model, a virus strain is represented by a localized solution concentrated around some given genotype. Emergence of new strains corresponds to a periodic wave propagating in the space of genotypes. The conditions of appearance of such waves and their dynamics are described.

Beginning with the classical works of Azbel, Hofstadter, and Wannier (see [1]–3]), unusual spectral properties of two-dimensional periodic systems in a uniform magnetic field attract ever increasing attention. The main results here are concerned with theoretical explanations of the quantum Hall effect discovered by K. von Klitzing [4] (Nobel Prize, 1985). From the mathematical point of view this subject is of considerable interest because of its relations to a number of modern areas of mathematics: theory of characteristic classes, non-commutative geometry, operator extension theory, fractal geometry, etc. (see, for example, the review articles [5]–[7]). The most interesting properties of periodic systems with a magnetic field are conditioned by the presence of two natural geometric scales, namely, the magnetic length and the size of an elementary cell of the period lattice. The commensurability (or incommensurability) of the scales leads to such a pecularity of the systems as the transition from a band structure of the spectrum to a fractal one. This transition is described by the flux–energy diagram known as the "Hofstadter butterfly" (see [2] and [3]). Nevertheless, because the number of flux quanta through a unit cell of a crystal lattice is very small for experimentally accessible values of the magnetic field strength, no energy spectrum of the Hofstadter type is observable in usual Hall systems. However, artificial two-dimensional periodic-modulated systems (so-called periodic arrays of quantum dots) have recently been produced in which the above geometric scales are comparable and, consequently, an experimental observation of the Hofstadter butterfly has become possible [8].

Plastic deformation of the surface layer leads to strengthening, i.e., to a change in the mechanical properties of the machined surface material. The strengthening of the surface parts directly affects the life cycle of the finished product. This study focuses on the quality management of the machined surface after machining of structural and stainless steels. The purpose of this study was to identify the strengthening degree of the machined surface due to processes occurring in the chip formation zone and on the rear surface of the cutting tool. This study has, produced a quantitative assessment of the causes for the increase in microhardness as a result of the force during the passing of the future surface layer through the plastic deformation area that develops in the chip formation zone and the plastic deformation produced by the impact of the rear surface of the cutting tool on the machined surface.

We made precision measurements of fluorescence kinetics of crystalline Gd3BWO9: Nd3+ doped powders at room temperature by the method of gated single photon counting technique in a wide range of Nd3+ concentrations. The powders were synthesized with a high temperature solid-state reaction. We managed to describe the concentration dependence of the impurity fluorescence self-quenching kinetics curves with the constant microparameters of energy migration C-DD = 2.97 nm(6)/ms and quenching energy transfer C-DA = 0.43 nm(6)/ms. The microparameters were found with the direct fitting of the curves to the analytical formula of microscopic theory derived specifically for concentration fluorescence self-quenching accounting energy migration over donors. The obtained ratio of the values of the microparameters z = C-DA/C-DD = 0.145 indicates a hopping mechanism of fluorescence self-quenching of the F-4(3/2) level of the Nd3+ ion. We developed a kinetic method to determine with high accuracy the concentrations of impurity rare-earth ions in crystals at low doping level, which is significantly higher than that for energy-dispersive X-ray spectroscopy (EDS) analysis. For arbitrary systems with fluorescence self-quenching, we obtained an analytical formula that allows us to calculate the value of the activator concentration at which the fluorescence brightness is maximum. For the studied Nd3+: Gd3BWO9 powder samples, the maximum brightness is realized at x(max)approximate to 2.98 at.%, which is in good agreement with the experimental value. (C) 2020 Elsevier B.V. All rights reserved.

A high statistics data sample of the decays of $$K^+$$ mesons to three charged particles was accumulated by the OKA experiment in 2012 and 2013. This allowed to select a clean sample of about 450 events with $$K^{+}\rightarrow \pi ^{+}\pi ^{-}\pi ^{+}\gamma $$ decays with the energy of the photon in the kaon rest frame greater than 30 MeV. The measured branching fraction of the $$K^{+}\rightarrow \pi ^{+}\pi ^{-}\pi ^{+}\gamma $$ , with $$E_{\gamma }^{*} > 30\ \hbox {MeV}$$ is equal to $$(0.71 \pm 0.05) \times 10^{-5}$$ . The measured differential branching fraction over photon energy is compared with the prediction of the chiral perturbation theory to $${\mathcal {O}}(p^{4})$$ . A search for an up-down asymmetry of the photon with respect to the hadronic system decay plane is also performed.

Ions injected into a multipole RF trap (where they are neutralized in charge-exchange reactions) are proposed to be used to determine the energy of electrons from the decay of the 229Th isomer. A conversion electron is emitted within a few microseconds after neutralization. A deceleration spectrometer with magnetic collimation coupled with the ion trap is planned to be used to determine the electron energy. The spectrometer’s design and the results from modeling are discussed.

An automatic landing of an unmanned aerial vehicle (UAV) is a non-trivial task requiringa solution of a variety of technical and computational problems. The most important is the precisedetermination of altitude, especially at the final stage of approaching to the earth. With currentaltimeters, the magnitude of measurement errors at the final phase of the descent may be unacceptablyhigh for constructing an algorithm for controlling the landing manoeuvre. Therefore, it is desirableto have an additional sensor, which makes possible to estimate the height above the surface of therunway. It is possible to estimate all linear and angular UAV velocities simultaneously with thehelp of so-called optical flow (OF), determined by the sequence of images recorded by an onboardcamera, however in pixel scale. To transform them into the real metrical values it is necessary toknow the current flight altitude and the camera angular position values. The critical feature of theOF is its susceptibility to the camera resolution and the shift rate of the observed scene. During thedescent phase of flight, these parameters change at least one hundred times together with the altitude.Therefore, for reliable application of the OF one needs to coordinate the shooting parameters withthe current altitude. However, in case of the altimeter fault presence, the altitude is also still to beestimated with the aid of the OF, so one needs to have another tool for the camera control. One of thepossible and straightforward ways is the camera resolution change by pixels averaging in computerpart which performed in coordination with theoretically estimated and measured OF velocity. Thearticle presents results of such algorithms testing from real video sequences obtained in flights withdifferent approaches to the runway with simultaneous recording of telemetry and video data.

The use of nanotechnology and the fields of application of nanomaterials are growing vastly, but the negative health effects on the exposed employees are not well studied. The standardized methods of monitoring of occupational exposure are still absent. The task of occupational physicians is to find the ways of evaluation of potential risks of exposure to engineered nanoparticles and to determine the biomarkers for early diagnostics and prevention of occupational diseases. The aim of our study was to detect and identify engineered nanoparticles in biological samples received from occupationally exposed subjects and to evaluate the association of findings with the results of external aerosol measurements on the workplace. The study cohort consisted of two groups of subjects. The first group was exposed to engineered nanoparticles containing mainly iron, manganese, and carbon compounds; the second group was exposed to the nanoparticles containing copper oxide. The post-shift biological samples (urine, blood serum, and exhaled breath condensate) were collected. The analysis was performed by transmission electron microscopy and energy-dispersive spectroscopy. The nanoparticles were detected in all the biological samples. The most common identified chemical elements were the biogenic ones (carbon, potassium, chlorine, oxygen), but the nanoparticles containing metals were identified in EBC, blood, and urine as well (gold, silver, copper, lanthanum, cerium, and tantalum). Our results demonstrate the possibility of detection of occupational exposure to the engineered nanoparticles in human biological fluids. Further studies are necessary to compare the pre-shift and post-shift burden of samples with engineered nanoparticles and to determine the magnitude of occupational exposure during the shift.

V.M. Abazov, B. Abbott, B.S. Acharya, M. Adams, T. Adams, J.P. Agnew, G.D. Alexeev, G. Alkhazov, A. Alton, A. Askew, S. Atkins, K. Augsten, V. Aushev, Y. Aushev, C. Avila, F. Badaud, L. Bagby, B. Baldin, D.V. Bandurin, S. Banerjee, E. Barberis, P. Baringer, J.F. Bartlett, U. Bassler, V. Bazterra, A. Bean, M. Begalli, L. Bellantoni, S.B. Beri, G. Bernardi, R. Bernhard, I. Bertram, M. Besançon, R. Beuselinck, P.C. Bhat, S. Bhatia, V. Bhatnagar, G. Blazey, S. Blessing, K. Bloom, A. Boehnlein, D. Boline, E.E. Boos, G. Borissov, M. Borysova, A. Brandt, O. Brandt, M. Brochmann, R. Brock, A. Bross, D. Brown, X.B. Bu, M. Buehler, V. Buescher, V. Bunichev, S. Burdin, C.P. Buszello, E. Camacho-Pérez, B.C.K. Casey, H. Castilla-Valdez, S. Caughron, S. Chakrabarti, K.M. Chan, A. Chandra, E. Chapon, G. Chen, S.W. Cho, S. Choi, B. Choudhary, S. Cihangir, D. Claes, J. Clutter, M. Cooke, W.E. Cooper, M. Corcoran, F. Couderc, M.-C. Cousinou, J. Cuth, D. Cutts, A. Das, G. Davies, S.J. de Jong, 30 E. De La Cruz-Burelo, F. Déliot, R. Demina, D. Denisov, S.P. Denisov, S. Desai, C. Deterre, K. DeVaughan, H.T. Diehl, M. Diesburg, P.F. Ding, A. Dominguez, A. Drutskoy, A. Dubey, L.V. Dudko, A. Duperrin, S. Dutt, M. Eads, D. Edmunds, J. Ellison, V.D. Elvira, Y. Enari, H. Evans, A. Evdokimov, V.N. Evdokimov, A. Fauré, L. Feng, T. Ferbel, F. Fiedler, F. Filthaut, 30 W. Fisher, H.E. Fisk, M. Fortner, H. Fox, J. Franc, S. Fuess, P.H. Garbincius, A. Garcia-Bellido, J.A. Garćıa-González, V. Gavrilov, W. Geng, 57 C.E. Gerber, Y. Gershtein, G. Ginther, O. Gogota, G. Golovanov, P.D. Grannis, S. Greder, H. Greenlee, G. Grenier, Ph. Gris, J.-F. Grivaz, A. Grohsjean, S. Grünendahl, M.W. Grünewald, T. Guillemin, G. Gutierrez, P. Gutierrez, J. Haley, L. Han, K. Harder, A. Harel, J.M. Hauptman, J. Hays, T. Head, T. Hebbeker, D. Hedin, H. Hegab, A.P. Heinson, U. Heintz, C. Hensel, I. Heredia-De La Cruz, K. Herner, G. Hesketh , M.D. Hildreth, R. Hirosky, T. Hoang, J.D. Hobbs, B. Hoeneisen, J. Hogan, M. Hohlfeld, J.L. Holzbauer, I. Howley, Z. Hubacek, 15 V. Hynek, I. Iashvili, Y. Ilchenko, R. Illingworth, A.S. Ito, S. Jabeen, M. Jaffré, A. Jayasinghe, M.S. Jeong, R. Jesik, P. Jiang, K. Johns, E. Johnson, M. Johnson, A. Jonckheere, P. Jonsson, J. Joshi, A.W. Jung, A. Juste, E. Kajfasz, D. Karmanov, I. Katsanos, M. Kaur, R. Kehoe, S. Kermiche, N. Khalatyan, A. Khanov, A. Kharchilava, Y.N. Kharzheev, I. Kiselevich, J.M. Kohli, A.V. Kozelov, J. Kraus, A. Kumar, A. Kupco, T. Kurča, V.A. Kuzmin, S. Lammers, P. Lebrun, H.S. Lee, S.W. Lee, W.M. Lee, X. Lei, J. Lellouch, D. Li, H. Li, L. Li, Q.Z. Li, J.K. Lim, D. Lincoln, J. Linnemann, V.V. Lipaev, R. Lipton, H. Liu, Y. Liu, A. Lobodenko, M. Lokajicek, R. Lopes de Sa, R. Luna-Garcia, A.L. Lyon, A.K.A. Maciel, R. Madar, R. Magaña-Villalba, S. Malik, V.L. Malyshev, J. Mansour, J. Mart́ınez-Ortega, R. McCarthy, C.L. McGivern, M.M. Meijer, 30 A. Melnitchouk, D. Menezes, P.G. Mercadante, M. Merkin, A. Meyer, J. Meyer, F. Miconi, N.K. Mondal, M. Mulhearn, E. Nagy, M. Narain, R. Nayyar, H.A. Neal, J.P. Negret, P. Neustroev, H.T. Nguyen, T. Nunnemann, J. Orduna, N. Osman, A. Pal, N. Parashar, V. Parihar, S.K. Park, R. Partridge, N. Parua, A. Patwa, B. Penning, M. Perfilov, Y. Peters, K. Petridis, G. Petrillo, P. Pétroff, M.-A. Pleier, V.M. Podstavkov, A.V. Popov, M. Prewitt, D. Price, N. Prokopenko, J. Qian, A. Quadt, B. Quinn, P.N. Ratoff, I. Razumov, I. Ripp-Baudot, F. Rizatdinova, M. Rominsky, A. Ross, C. Royon, P. Rubinov, R. Ruchti, G. Sajot, A. Sánchez-Hernández, M.P. Sanders, A.S. Santos, G. Savage, M. Savitskyi, L. Sawyer, T. Scanlon, R.D. Schamberger, Y. Scheglov, H. Schellman, 48 M. Schott, C. Schwanenberger, R. Schwienhorst, J. Sekaric, H. Severini, E. Shabalina, V. Shary, S. Shaw, A.A. Shchukin, O. Shkola, V. Simak, P. Skubic, P. Slattery, G.R. Snow, J. Snow, S. Snyder, S. Söldner-Rembold, L. Sonnenschein, K. Soustruznik, J. Stark, N. Stefaniuk, D.A. Stoyanova, M. Strauss, L. Suter, P. Svoisky, M. Titov, V.V. Tokmenin, Y.-T. Tsai, D. Tsybychev, B. Tuchming, C. Tully, L. Uvarov, S. Uvarov, S. Uzunyan, R. Van Kooten, W.M. van Leeuwen, N. Varelas, E.W. Varnes, I.A. Vasilyev, A.Y. Verkheev, L.S. Vertogradov, M. Verzocchi, M. Vesterinen, D. Vilanova, P. Vokac, H.D. Wahl, C. Wang, M.H.L.S. Wang, J. Warchol, G. Watts, M. Wayne, J. Weichert, L. Welty-Rieger, M.R.J. Williams, G.W. Wilson, M. Wobisch, D.R. Wood, T.R. Wyatt, Y. Xie, R. Yamada, S. Yang, T. Yasuda, Y.A. Yatsunenko, W. Ye, Z. Ye, H. Yin, K. Yip, S.W. Youn, J.M. Yu,

This chapter considers the methods to increase the performance and reliability of the reprofile machining of the wheel tread profile. Proceeding from the fact that both in milling and turning, the cutting tool is a key element to ensure performance and reliability of the manufacturing process, the study considers the methods to increase the performance properties of cutting tools. In particular, the study includes the investigation of the following ways to improve cutting tools (carbide inserts) to machine wheel tread profile: replacement of traditional grades of WC-TiC-Co carbides with more efficient ones based on WC-TiC-TaC-Co; application of special thermally conductive pads, gaskets, and pastes to improve the distribution of heat flows in the cutting zone; and application of modern nanoscale composite multilayer coatings (NMCC). It is noted that even higher performance can be obtained by combining the above three methods, in particular, by combining application of special thermal pads and NMCC.