Infrared Effects

It is shown that the presence of zero mass particles makes the elements of the S-matrix divergent. We explain the physical origin of such divergences. We argue that they are due to the long range of the interactions which violate the assumptions we made when we derived the asymptotic conditions for scattering. We study these divergences in the particular case of QED at tree, as well as one-loop level and present the Bloch–Nordsieck solution. We show that the cancellation of infrared divergences among virtual exchanged and real emitted soft photons is true to all orders in the perturbation expansion and we obtain the Sudakov double logarithm formula for Coulomb scattering.

Dynamical Grooming meets LHC data

In this work, we analyse the all-orders resummation structure of the momentum sharing fraction, zg, opening angle, θg, and relative transverse momentum, kt,g, of the splitting tagged by the Dynamical Grooming procedure in hadronic collisions. We demonstrate that their resummation does non-exponentiate and it is free of clustering logarithms. Then, we analytically compute the probability distributions of (zg, θg, kt,g) up to next-to-next-to-double logarithm accuracy (N2DL) in the narrow jet limit, including a matching to leading order in αs. On the phenomenological side, we perform an analytic-to-parton level comparison with Pythia and Herwig. We find that differences between the analytic and the Monte-Carlo results are dominated by the infra-red regulator of the parton shower. Further, we present the first analytic comparison to preliminary ALICE data and highlight the role of non-perturbative corrections in such low-pt regime. Once the analytic result is corrected by a phenomenologically determined non-perturbative factor, we find very good agreement with the data.

Correlation Analysis of Sprint Performance and Reaction Time Based on Double Logarithm Model

In sprint track events, the starting reaction time is an important professional capacity of the athletes, and it is closely related to their performance. This study examines the reaction time and the results of the male and female sprinters participating in the World Athletics Championships from 2011 to 2019 in the 100 m, 200 m, 100 m, and 110 m hurdles. The researchers used least squares estimation, multivariate analysis of variance, and other methods and theories to construct a double logarithmic model and a multivariate analysis of a variance model. The researchers used Econometrics Views and SPSS software programs to analyze the correlation between the performance and the starting reaction time, as well as the patterns in the changes of the reaction time of athletes of both genders in different types of and rounds in the competitions. Research results show that there is a direct correlation between the reaction time and the performance, and the degrees of correlation vary depending on the gender of the athlete, year of competition, type of competition, and round of competition. There is a correlation between the foul types and the type of competition, but there is no correlation between foul types and the gender of the athlete. The research results are science-based and are of practical value and thus can be used as a reference by coaches in sprint running to offer more professional guidance to the athletes.

A Whole-Range S–N Curve for Fatigue Assessment of Steel Orthotropic Bridge Decks

The fatigue assessment of orthotropic bridge decks under routine traffic loading is a significant task to ensure the serviceability and safety of steel bridges. The sequential law computes fatigue damages using whole-range [Formula: see text]–[Formula: see text] curves and sequential stress histories and has been proven to provide more realistic results than Miner’s rule under variable amplitude loading. In this paper, a whole-range [Formula: see text]–[Formula: see text] curve covering the very low-cycle region, the low-cycle region, the finite life region, the high-cycle region, and the very high-cycle region is proposed for the sequential law to evaluate the fatigue performance of steel orthotropic bridge decks. The mathematical model of the whole-range [Formula: see text]–[Formula: see text] curve is first deduced based on the partially known [Formula: see text]–[Formula: see text] curve recommended in steel bridge design codes. The properties of the whole-range [Formula: see text]–[Formula: see text] curve are then explained from the geometrical point of view in the double logarithm coordinates system. Finally, rib-to-deck joints in steel orthotropic bridge decks are used as a case study. Fatigue test data are used to validate the proposed model. The whole-range [Formula: see text]–[Formula: see text] curve, with a 97.5% survival limit, is established for fatigue assessment of rib-to-deck joints in real bridges. The results show that the proposed whole-range [Formula: see text]–[Formula: see text] curve allows a good fit of experimental data and excellent agreement with code [Formula: see text]–[Formula: see text] curves in the finite life region and provides an effective extrapolation from the finite life region to the whole range of cycle numbers.

Evaluation of the interactions between human serum albumin (HSA) and warfarin or diflunisal by using molecular fluorescence using two approaches

<p class="PaperH1">Serum albumin is the main drug transporter of the bloodstream and contains two main binding sites: Sudlow I or acidic drug binding site, and Sudlow II or benzodiazepine binding site. Warfarin, a well-known anticoagulant drug commonly used in the prevention of thrombosis and thromboembolism, binds to Sudlow I site, whereas non-steroidal antiinflammatory drugs (NSAIDs) such as diflunisal bind preferentially to Sudlow II site. Albumin is a fluorophore that modifies its fluorescence (quenching or enhancement effect) when it is bound to a drug. The application of the double logarithm Stern-Volmer equation allows the calculation of the stoichiometry and the binding constant of the process. This procedure does not consider the possible interferences coming from the fluorescence of the drug though. Another strategy to evaluate the binding constants is to consider the whole spectrum, taking into account all the possible species in equilibrium; in this case we have used an extended version of the STAR program, which can deal with 300 spectra, each containing up to 300 data points. The aim of this work is to compare both approaches to evaluate the interaction between warfarin (Sudlow I) and diflunisal (Sudlow II) and HSA: the double logarithm Stern-Volmer equation and the STAR program.</p>

Joint Resummation for TMD Wave Function of Pion

QCD corrections to transverse-momentum-dependent pion wave function develop the mixed double logarithm [Formula: see text], when the gluon emission is collinear to the energetic pion. The fist scheme-independent kT factorization formula for γ*π → γ transition form factor is achieved by resumming all the enhanced logarithms for both pion wave function and short-distance coefficient function. High-order QCD corrections and transfer momentum [Formula: see text] dependence of pion form factor are found to be distinct from those predicted by the conventional resummation approach.

Numerical Simulation of Cell Growth Pattern and Determination of Fractal Dimension of Cell Cluster

Life system behaves self-similar properties from microcosms to macrostructure. Based on the cell growth roles, the cell cluster growth process is simulated. The sandbox method and box counting are used for determining the fractal dimension of cell associated with the geometrical structure of growing deterministic fractals. The fractal dimension of cell shape is estimated according to the slope of line between the numbers of boxes and box size in double logarithm coordinates.

Die Wall Lubricated Warm Compaction of Fe-Ni-Cu-Mo-C Powders

The combination of warm compaction and die wall lubrication, called die wall lubricated warm compaction was used to make Fe-Ni-Cu-Mo-C powder metallurgy material. Results showed that the green density could be 7.38 g•cm-3 under the pressure of 700MPa at the temperature of 120°C. The sintered density could be 7.34 g•cm-3 and dimension change was 0.19% when sintered at 1200°C for 50 minutes. Both green density and spring back effect gradually increased as the compacting pressure rose. The relation between compacting pressure and green density could be described by Huang Pei-yun double logarithm equation. Different forming conditions effecting green density in turn from big to small were compacting pressure, lubrication, compacting temperature, mixing method and compacting speed.