UNKNOWN SEAL OF EMPEROR JUSTIN I (518-527) FROM SERDICA

The paper examines a seal of Emperor Justin I (518-527). It has the following description: Obverse: Beardless bust with a nimbus of Emperor Justin I, opposite, with a helmet and chlamys. Around the image an inscription in clockwise direction: N IVSТI NVSPPAVG = D(ominus) n(oster Justinus p(er)petus Aug(ustus) Reverse: Victoria standing across with a wreath in each hand, in the bottom left field a small So far there is not known bulla of this ruler from Bulgaria and because of that some questions arise when identifying the specimen from Serdica. The inscription on the newly discovered seal showed that the bulla belonged to Justin, but it is not clear if it is Justin I (518-527) or Justin II (565-578). The image on the obverse differs from the known images of Justin I and Justin II. It is smaller and occupies part of the nucleus, while in the published so far the size of the bullotirium is larger than the nucleus itself. The inscription of the copy from Serdica is clearly legible, but the letters and the image are small, which distinguishes this seal from the known so far. The difference is obvious also in the reverse, in which Victoria does not follow the model of the image from the molybdenums of Justinian I and Justin II, but her image is close to that of the seals of Anastasius I, and even could be said that it completely copies it. The characteristics of the seal, its inscription and images are different from the ones of the copies of Justin II, which is a serious reason to attribute it to the time of Emperor Justin I, which makes it currently unique of this type. Other evidence of life in Serdica from the time of Emperor Justin I (518 - 527) are the coins discovered. In Serdica the most numerous are the coins of 40 nummi, followed by those of 20 nummi, which are almost two times less than the large denomination. The number of the specimens of 10 and 5 nummi is equal, but is less than the number of the large denominations. As mints, the coins from Constantinople predominated, followed by coins from Nicomedia, Antioch and Cyzicus. Among the regular coins were found two imitations of folles of Justin I, which imitate the production of the mint of Constantinople from this period. These coins, found together with the official ones used in the Byzantine state, show that they were accepted by the financial authorities as a regular payment tool. Two gold coins of Justin I are discovered in Serdica I - a solidus found at the eastern fortress wall and a tremis from the excavations at the northeastern tower. The new seal of Emperor Justin I presented in the article and the coins discovered by this ruler in Serdica show the significant role of the city during this period.

Attention allocation on mobile app interfaces when human interacts with them

With the popularity of smartphones and the pervasion of mobile apps, people spend more and more time to interact with a diversity of apps on their smartphones, especially for young population. This raises a question: how people allocate attention to interfaces of apps during using them. To address this question, we, in this study, designed an experiment with two sessions (i.e., Session1: browsing original interfaces; Session 2: browsing interfaces after removal of colors and background) integrating with an eyetracking system. Attention fixation durations were recorded by an eye-tracker while participants browsed app interfaces. The whole screen of smartphone was divided into four even regions to explore fixation durations. The results revealed that participants gave significantly longer total fixation duration on the bottom left region compared to other regions in the session (1) Longer total fixation duration on the bottom was preserved, but there is no significant difference between left side and right side in the session2. Similar to the finding of total fixation duration, first fixation duration is also predominantly paid on the bottom area of the interface. Moreover, the skill in the use of mobile phone was quantified by assessing familiarity and accuracy of phone operation and was investigated in the association with the fixation durations. We found that first fixation duration of the bottom left region is significantly negatively correlated with the smartphone operation level in the session 1, but there is no significant correlation between them in the session (2) According to the results of ratio exploration, the ratio of the first fixation duration to the total fixation duration is not significantly different between areas of interest for both sessions. The findings of this study provide insights into the attention allocation during browsing app interfaces and are of implications on the design of app interfaces and advertisements as layout can be optimized according to the attention allocation to maximally deliver information.

Construction of multichannelmagnetolevitation systems

Background: It is proposed to set a traveling magnetic field in a special control channel (beam, pipe), coupled with several controlled channels - small-sized maglev systems in which levitation of transport modules is carried out. Aim: to interface the control channel with several controlled channels (up to four) small-sized maglev systems. In this case, the control channel will be located in the center, and the controlled channels at the top, right, bottom, left. Methods: 3D-modeling, layout, spatial composition, patent search. Results: The traveling magnetic field in the control channel is created by a moving sequence of interacting magnetic field sources the movers, which interact too with magnetic field sources of transport modules the fellow travelers, levitating in the controlled channels through sources of a constant magnetic field. The structure is installed on arched supports that uniformly distribute the load over the support surface. A model of a two-channel system with a lower location of a controlled channel has been developed. Conclusion: The small-sized maglev systems can form a multi-channel transport system.

Dynamics of a neutrally buoyant circular particle moving in a parallel double-lid-driven square cavity

The motion of a neutrally buoyant circular particle in a parallel double-lid-driven square cavity is studied with the lattice Boltzmann method. To understand, predict and control the motion of the circular particle, the effects of the initial position and particle size are studied. If the circular particle is placed at the centerline of the square cavity, at the steady state, it is confined at the bottom left corner, otherwise, the circular particle is stabilized at the 8-like trajectory, which is created by both the inertia of the circular particle and the confinement of the boundaries of the square cavity. The effect of the particle size on the motion of the circular particle is obvious, with the increase of the particle size, the confinement of the boundaries of the square cavity becomes stronger, and the 8-like trajectory shrinks toward the center. Furthermore, if the particle size is large enough, the centrifugal motion of the circular particle becomes weaker, and the circular particle cannot cross the centerline of the square cavity.

Descending Packing Algorithm for Irregular Graphics Based on Geometric Feature Points

The packing for two-dimensional irregular graphics is one of the NP-complete problems and widely used in industrial applications. In this paper, a descending nesting algorithm for a two-dimensional irregular graph based on geometric feature points is proposed. Before the packing, the parts to be packed are sorted, matched, and spliced, and the matching of the rectangular pieces and the rectangular-like pieces is carried out according to the plate size. On this basis, the geometric feature points of the parts are used to construct the packing baseline, and the packing is accurately carried out according to the principles of the bottom left, the principle of the lowest center of gravity, and combination with virtual moving, rotating collision calculation. The computation of the moving collision distance between the graphics is replaced by the projecting computation of the geometric feature points of the graphic parts, so the computation amount can be reduced. Also, this method is used to test a number of benchmarks examples which are provided by ESICUP (EURO Special Interest Group on Cutting and Packing), which show that the proposed algorithm not only can improve packing but also has better stability and reliability.

Erratum: N.P. Neugodova et al., Current approaches to the abnormal toxicity test

Neugodova N.P., Stepanyuk E.O., Sapozhnikova G.A., Sakanyan E.I., Ryabtseva M.S. Current approaches to the abnormal toxicity test. Vedomosti Nauchnogo tsentra ekspertizy sredstv meditsinskogo primeneniya = The Bulletin of the Scientific Centre for Expert Evaluation of Medicinal Products. 2020;10(2):82–88. https://doi.org/10.30895/1991-2919-2020-10-2-82-88Dear readers, on page 84 (second paragraph from the bottom, left column) in issue 2 of The Bulletin of the Scientific Centre for Expert Evaluation of Medicinal Products, 2020 (2020;10(2):82–88) the following statement: “The discussions centered around suppression of the abnormal toxicity test and target animal batch safety test for vaccines for human use, and the possibility of suppression of the laboratory animal batch safety test for veterinary vaccines” should read: “The discussions centered around suppression of the abnormal toxicity test for vaccines for human use, and the possibility of suppression of the laboratory animal batch safety test and target animal batch safety test for veterinary vaccines”.

Localization and steric effect of the lone electron pair of the tellurium Te4+ cation and other cations of the p-block elements. A systematic study

A simple method has been developed based on pure geometrical concepts to localize lone pairs (LPs) of cations of the p-block elements and model their steric effect. The method was applied to 1185 structures containing LP cations in 2439 non-equivalent positions. For oxide crystal structures, it is observed that, going from bottom left to top right in the periodic table, LPs move away from the cation core and decrease in size. For a given kind of cation M*, the LP radius increases linearly with the M*–LP distance, the smallest rate being observed for Tl+ and the largest for Cl5+. The influence of the anion type was also studied in the case of the Te4+ cation. Overall, the same trends were observed. The smallest Te–LP distances and LP radii are found for anions of large size and small charge.

Analysis of Stress, Strain, and Fatigue Strength of the Rotary Table of Boom-type Roadheaders

The rotary table is the key component in the optimal design of roadheaders. In this study, a simulation model of the cutting part and a rotary table is established in SolidWorks, and stress analysis and strength evaluation of the structure of the rotary table are performed. To this end, finite element analysis is performed on the basis of the dynamic theory of a coupled multibody system comprising rigid and flexible bodies. Considering actual working conditions, the load file of the cutting head is calculated based on the development of the “Roadheader Machine load Calculation Program”, and the stress and strain cloud map of the cutting head running to the bottom left, middle end, and right end of the rotary table is obtained through Adams simulation. Then, the 6-order modal analysis is carried out, and the S-N curve of the turntable is finally established. In addition, the fatigue life reliability of the turntable is analyzed using the AWE fatigue module. The results show that, provided reliable working conditions, the EBZ160 type roadheader machine during the normal service life shows no risk of fatigue failure under normal working load.