Digitalization of BSR (buyer supplier relationship) is generally one of the effective tools to strengthen the supply chain. This study aims to establish the correlations between the perceived importance of BSR, investment in BSR digitalization and ER (economic result) change. Data collecting was realized in the form of a questionnaire survey. This survey was carried out in Czech enterprises of different focuses and sizes. Hypotheses are tested using Pearson's Chi-squared test. The study confirmed that correlation between the perceived importance of BSR and investment to BSR digitalization is stronger for producers than for service providers. The investment in BSR digitalization brings about ER development in the short term only for services providers. Enterprises do not associate the development of ER and the importance of BSR. BSR is considered an important area as part of the SCM whole, but ER development is not associated with this area, nor does investment in this area have a clear economic effect in a recession. Thus, the logical triad of "importance of the process- investment in process development – process effect" is unprovable in the case of BSR digitalization in a recession.

Nitrones are an interesting group of organic compounds due to their spin-trapping properties. These chemical compounds are also useful building blocks via cycloaddition reactions. In this work, a comprehensive study about correlation of selected parameters come from quantum chemical and experimental studies, namely 1H chemical shifts, IR absorption bands and UV-Vis maximum absorptions as well as reactivity descriptors such as global electrophilicity and nucleophilicity with substituent constants of Hammett, Taft, Brown and Okamoto's as well as Exner for para substituent analogues of (Z)-C-phenyl-N-methylnitrones have been study. Based on presented results it should be noted that tested models of substituent constants correlate in a satisfactory way with computational data. The opposite conclusion is observed for spectral data derived from analysis performed for synthesized nitrones. The obtained results constitute a useful element for future research on reaction mechanisms involving the tested nitrones.

The Quadratic Assignment Problem (QAP) is one of the classical combinatorial optimization problems and is known for its diverse applications. The QAP is an NP-hard optimization problem which attracts the use of heuristic or metaheuristic algorithms that can find quality solutions in an acceptable computation time. On the other hand, there is quite a broad spectrum of mathematical programming techniques that were developed for finding the lower bounds for the QAP. This paper presents a fusion of the two approaches whereby the solutions from the computations of the lower bounds are used as the starting points for a metaheuristic, called HC12, which is implemented on a GPU CUDA platform. We perform extensive computational experiments that demonstrate that the use of these lower bounding techniques for the construction of the starting points has a significant impact on the quality of the resulting solutions.

The presented article deals with the mathematical modeling of aircraft ground handling on the service apron to utilize ground personnel more efficiently in the case of existing substitutability of workers. This article proposes a supporting decision-making tool for effective planning of the aircraft ground handling. This tool will be used for a selected type of aircraft and using the minimum number of personnel participating in the aircraft ground handling procedure. The optimization is based on the original mathematical programming model and its solution. Computational experiments verifying the functionality of the proposed model were performed on current data from the Ostrava International Regional Airport in the Czech Republic. The originality of the proposed approach (apart from the original model) comes with introducing the substitutability of workers of individual qualifications and the decomposition of workgroups composed of workers of the same qualification down to the level of individual workers. Above-mentioned decomposition of workgroups enables the flexible and separate transfer of individual workers included in the same groups between activities in the event of downtime of the given group and the existence of an activity that is not covered by the required number of workers. The substitutability of workers and the decomposition of individual groups down to the level of individual workers will make it possible to lower the number of workers or verify that the number of workers is optimal and eliminate potential staff downtime.

This work is devoted to development of optimum recipes of high-strength concretes based on filled binders with fine-milled anthropogenic mineral filler intended for earthquake resistant high-rise monolithic construction. The optimum recipes of concretes in this work have been developed on the basis of computations and experimental designing of cast concrete mixes with chemical additives and anthropogenic mineral fillers, as well as destructive inspection methods as the most precise for analysis of physicomechanical and deformation properties of concrete. The following raw materials have been used for production of high-strength concretes: natural quartz sands with the fineness modulus F.M. = 1.7-1.8; crushed limestone with the particles sizes of 5-20 mm; water reducing chemical additives and hardening retarder to control specifications of concrete mixes; plain Portland cement, grade PTs 500 D0; anthropogenic mineral additives (fillers) in the form of crushed concrete and ceramic bricks. Optimum recipes of monolithic concretes have been designed using anthropogenic raw materials including normal concrete grades with compressive strength of M30-M40 and high-strength concrete grades of M50-M80, characterized by high homogeneity of cement stone with significantly finer pores and lower shrinkage. Herewith, it has been established that fine-milled anthropogenic mineral filler in the form of crushed concrete and ceramic bricks at the ratio of 70:30, respectively, efficiently influences specifications of concrete mixes on their basis significantly increasing resistance of the mix against sedimentation and water gain. It has been established that the developed high-strength concretes based on filled binders with fine-milled anthropogenic mineral filler are characterized by high freeze–thaw resistance (from F400 to F600) and water tightness (W14 and higher), which is a solid base providing high lifecycle of such concretes.

This paper focuses on the application of foamed bitumen technology in the production of asphalt mixtures. This technology replaces the common asphalt binder with foamed bitumen for production of asphalt mixtures. Given the foaming, it is possible to produce asphalt mixture at a lower working temperature. This “eco-friendly” technology has been increasingly used by the asphalt mixture producers in Europe because of reducing the energy demands of the asphalt mixture productions. In this paper, first the technology of the foamed bitumen production is explained and then the results of laboratory research are presented, in which selected empirical and functional parameters of two types of asphalt mixtures of the asphalt concrete type (AC) are compared. These mixtures were produced in two versions, one of them containing the common asphalt binder and the other one the foamed bitumen. While comparing the samples, attention was paid especially to the comparison of the stiffness modulus of the laboratory-produced asphalt mixtures according to EN 12697-26 and to their low-temperature characteristics according to EN 12697-46.

Mastic mortar, i.e. a mixture of bitumen and very fine filler particles (i.e. aggregate fine particles smaller than 0.063 mm), can significantly co-influence not only rheological properties of the processed asphalt mixture, but also the visco-elastic properties of compacted asphalt layers including resistance against crack formation. Nevertheless, the number of scientific studies dedicated to this topic in detail, is very limited. The aim of this work is to determine the basic rheological properties of these mastic materials using a dynamic shear rheometer, in particular concentrating on the petrographic origin of the filler particles. Fourteen filler types were selected and mixed with paving bitumen 70/100 in various ratios. Petrographic composition of the individual fillers was determined using powder X-ray diffraction analysis. Attention was given especially to the effect of the presence of mica on the filler and mastic properties. Filler properties were analyzed using the voids of dry compacted filler test so-called "Rigden voids" and the delta ring and ball test. Mastic mortars prepared in a laboratory were subjected to multiple stress creep and recovery test and oscillation measured at 60 °C in a dynamic shear rheometer. Results show that using dynamic shear rheometer to determine the properties of these materials is advantageous. Petrographic origin of the filler to a great extent affects the behavior and properties of the mastic mortar, especially its stiffening effect. Limestone filler stiffened the bituminous binder the least and reference materials, containing high ratio of mica, stiffened the binder the most.