Increasing the performances of low permeable cement composites

Introduction. The purpose of the article is to expand the range of compositions for special structures, which will allow them to be operated in extreme conditions. To achieve this goal, a number of tasks have been solved containing ways to improve the efficiency of composites, incl. low-permeability ones. Materials and methods. The research methodology includes a system of transdisciplinary approaches that evaluate the composite as a complex system, taking into account the provisions of geomimetics, such as the law of similarity, the law of affinity of structures, technogenic metasomatism, and micromechanics of composite media. Results. A wide range of cement concretes has been created for unique objects: low-permeability (for protective objects, reservoirs and hydraulic structures). The developed composites have the following performance characteristics (the results for the control sample are given in parentheses): water absorption by weight — 2.5 % (6.1 %), waterproof grade — W14 (W10), air permeability — 0.0253 cm3/s (0.0565 cm3/s), vapor permeability — 0.0021 mg/(m-h-Pa) (0.0030 mg/(m-h-Pa)), effective diffusion coefficient — 1.34 · 10–4 cm2/s (1.56 · 10–4 cm2/s). Conclusions. The similarity in the work of the components of different composite binders, incl. During the two-stage hydration of clinker minerals, in particular, in the first phase, the formation of low-density compounds of different phases occurs, and in the second phase, the binding of calcium hydroxide to low-basic crystalline hydrates occurs. The increase in the activity of the composite binder is due to the synergistic effect of a number of reasons: amorphous silica-containing components bind Ca(OH)2, released during the hydration of clinker minerals, in the second generation CSH(I); limestone particles clog the pores, compacting the structure; and fly ash microspheres are centers of crystallization of new growths.

Analysis of steady flow in a circular cylindrical pipe with hydraulically smooth walls

Анализируются формулы для скоростей и сопротивлений при установившемся течении несжимаемой вязкой жидкости в круглой цилиндрической трубе. Используется закон подобия скоростей при турбулентном режиме течения для получения представления коэффициента сопротивления в явном виде. Рассматривается связь между числами Рейнольдса, вычисляемых по средней и по динамической скоростями. Сформулирован принцип нахождении профилей скорости по закону сопротивления. Приведены аналитические выражения для всего универсального профиля скоростей. Приводится алгоритм построения кривой сопротивления по профилю скоростей в универсальных координатах. Предлагается единая формула для коэффициента сопротивления при любом режиме течения и формула для учёта отклонения от логарифмики на профиле скоростей в области вблизи оси трубы. The formulas for the velocities and resistances in the steady flow of an incompressible viscous fluid in a round cylindrical pipe are analyzed. The law of similarity of velocities in the turbulent regime is used to obtain an explicit representation of the drag coefficient. The relationship between the Reynolds numbers calculated by the average and dynamic speeds is considered. The principle of finding velocity profiles according to the law of resistance is formulated. Analytical expressions are given for the for any flow regime and a formula for taking into account deviations from the logarithm on the velocity profile in the region near the pipe axis.

Retransmission of Historical Lace Ornaments Using 3D-design Method

In this article, it is shown the solution of a range of important issues that are necessary for working out of the modern digital stages of a lace costume and lace–like structures. The most complete study of the historical–cultural heritage of lace is a prerequisite for the construction of a classification matrix that highlights the dominant types of lace in certain time intervals in different countries. Understanding the conditions of traditional design of a lace element with an ornamental pattern, historically natural to its time, allows recreating a certain prototype of a lace element, lace costume, lace style image. The classification matrix provides the possibility of authentic adaptation of historical lace ornaments using the 3D printing method and 3D modelling programs. On the basis of selected historical prototype sketching of the interested area of a costume is carried out from the historical art canvas according to the actual measurements of the elements and the mathematical law of similarity, with a subsequent 1:1 scaling. The copy of maximum possible similarity of the historical prototype with the use of special 3D-programs is transleted from the flat intangible artifact of the great artist into a real stylized 3D-object. Through such modular elements, it is possible to assemble a full-value historical costume or a futuristic style image. In this research is carried out retransmission of the rapport elements of women’s and men’s costume collars. The table shows the key steps in the development of historical prototypes of 3D modules in Adobe Photoshop and Autodesk 3ds Max programs. From the designed modules according to the author’s principle, models of women’s and men’s costume in the style of futurism have been developed. The final models in the costume design chain show a complete difference in costume style and purpose from direct historical prototypes, which proves the absolute adaptive ability of lace to the changing conditions of the existence of the costume.

APPLICABILITY VERIFICATION OF AUTOFORM SOFTWARE FOR FEM SIMULATION OF MECHANICAL FIXATION OF HEMMED JOINTS

This paper deals with the problematics of fixation of hemmed joints, especially with one specific mechanical method how to ensure a dimensional stability of a hemmed joint of car-body parts, such as doors, bonnet and trunk lid, during the production process in the automotive industry. It also evaluates simulations and verify the possibility of the use of the Autoform software for this problematics. In the paper, the possibility of using the law of similarity in the analysis of the compressibility of small parts by Autoform is described.

Realization of the Similarity Law in the Building Material Science

The need for high quality of building products and structures determines the urgency of creating new ways to control the processes of forming the internal structure of modern composite building materials. This article discusses some aspects and problems on designing high-powder composites based on the law of similarity. The results showed that the determination of the compositions of these materisls and high adhesion property to each other and a low deformation characteristic. The results demonstrated that this less deformation characteristics is due to the similarity of the thermai expansion coefficients of the concrete components.

The Effect of Similarity Between a Product’s Shape Properties and the Benefit Offered on Judgments and Preferences

Studies show a product's shape affects consumer judgments. Yet, the basic principle that governs shape effects is unclear. In this study, we fill this gap by demonstrating that causal-reasoning considerations govern shape effects. Specifically, people expect cause (e.g., an energy drink) and its effect (e.g., fat burning) to exhibit some degree of resemblance or congruency (“like causes like”). This expectation leads them to use the “law of similarity” heuristic when judging artifacts. In two studies, we focused on a product's shape. For half of the products, the shape was an intrinsic property of the product (i.e., had the causal power to produce the effect), and for the other half, the shape was an extrinsic property of the product. For both kinds of properties (extrinsic and intrinsic), we demonstrate that the same ad (e.g., an energy drink that "claims" to produce fat burning) is more persuasive (willingness to purchase the product, and choice between products) when the product's shape is congruent rather than incongruent (e.g., a “tall” can vs. a “short” can) with the effect promised.We strengthen the notion that leaning on a cause-effect-similarity heuristic is very basic, by showing that choice situations accelerate the effect of congruency more for products for which the focal property is extrinsic than for products for which it is intrinsic.In line with other studies that show causal reasoning considerations govern judgment and choice on artifacts (products), the present study demonstrates causal-reasoning considerations govern judgment and choice concerning the cause-effect-similarity heuristic as well.

The Effect of Similarity Between A Product's Packaging Color and the Benefit Offered on Judgments and Preferences

Studies show a product's color affects consumer behavior. Yet the basic principle that governs color effects is unclear. In this study, we fill this gap. We demonstrate that causal-reasoning considerations govern color effects. Specifically, people expect that a cause and its effect should exhibit some degree of resemblance or congruency (“like causes like”), which leads them to use the “law of similarity” heuristic. In two studies, using various products, we focused on an irrelevant aspect of the product’s color—the color of its packaging. We demonstrate that the same ad (e.g., a patch that prevents mosquito bites) was more persuasive (willingness to purchase the product – henceforth WTP, and preference) when the product’s packaging color was congruent (pinkish) with the effect promised (calm skin) than when it was not (red).We strengthen the notion that leaning on a cause-effect-similarity heuristic is very basic, by showing that individual differences in thinking style have a very small effect on moderating this tendency.In line with other studies, which shows that causal-reasoning considerations (as previous knowledge and metal causal structure) govern judgment and choice on artifacts (products), the present study demonstrates that causal-reasoning considerations govern judgment and choice concerning cause-effect similarity heuristic as well.