Foam Polymers in Multifunctional Insulating Coatings

The application of foamed polymers as one of the components of insulating coatings allows to solve the problems of energy saving and creation of optimal operating conditions for constructions. The systems of application of energy-efficient heat-insulating materials must consider both the particularities of the insulating materials and the functional orientation of the constructions. The implementation of the concept of seamless insulating coatings implies the achievement of thermal effect and reduction in air permeability both by means of the application of thermal insulation with low thermal conductivity and the minimization of junctions between separate elements of the insulating coating, which is achieved using elastic foamed polymers and, first of all, polyethylene foam. Construction of seamless insulating coatings creates practically impermeable heat, vapor, and water barriers along the outer perimeter of the insulated object. Multilayer products based on polyethylene foam represent a relatively new material—a fact that requires examination of their properties, as well as under various operating conditions, and development of a methodology for evaluation of the operational resistance of these materials in structures of different purposes, including cold conservation. The performed tests have shown that the compressive strength at 10% deformation is determined by the function of load application area and varies from 70 kPa during the test of cube samples of 10 × 10 × 10 in size to 260 kPa for areas exceeding 100 m2. The longitudinal tensile strength amounts to 80–92 kPa, and the strength of the weld seam is equal to 29–32 kPa. It has been established that the values of thermal conductivity of polyethylene foam with an average density of 18–20 kg/m3 amounts to 0.032–0.034 W/(m·K), diffusion moisture absorption is equal to 0.44 kg/m2 without a metallized coating and 0.37 kg/m2 with a metallized coating; water absorption after partial immersion in water for 24 h amounts to 0.013 kg/m2; water absorption by volume after complete water immersion for 28 days is equal to 0.96%. The material does not practically change its properties under conditions of long-term temperature alteration from −60 to +70 °C. The developed and implemented insulation systems for protective surfaces of framed construction objects, rubbhalls and frameless structures, floating floors, indoor ice rinks, and snow conservation systems are presented.

Histogenetic morphotypes of rats respiratory system at the stages of early and late fetogenesis

Aim. Morphological analysis of the deployment of histogenetic information of pulmonary parenchyma at the stages of late embryogenesis and fetogenesis in laboratory rats within the limits of the norm of reaction with verification according to morphometric criteria of individual morphotypes.Materials and methods. Comparative morphological study of histogenesis of endodermal derivatives of the lungs of rats at critical periods of intrauterine development – late embryogenesis (day 14 of gestation), and late fetogenesis (day 20 of gestation) was performed using morphometric identification of plane parameters and a complex of plane form factors of epithelial structures of the lung. Morphometric studies were carried out in the Morphometer program on semi-thin sections of the rat lung.Results. Two critical stages of histogenesis of entodermal beginnings of fetal lungs are described – pseudoglandular and canalicular. The options of discordance of individual development within the response norm are justified. The lungs of the fetus at the pseudoglandular stage and the canalicular stage show significant fluctuations in the plane values of the pulmonary parenchyma, the presence in different individuals of variants of the plane values of entodermal derivatives, which indicated individual morphotypes of the development of the rat lung. At the pseudoglandular stage, in fetus with type I, called “compact”, the total area of the tubular system and the total perimeter are significantly inferior (p<0.001) to the same indicators of the lung II morphotype, designated as “air”. The values of one tubule (the outer perimeter, its area, the dimensions of the X-projection and Y-projection, the length of the epithelial tubes) in type I, on the contrary, are significantly larger than in type II (p<0.01). Among form factors, reliable differences have elongation (FE), squareness (FQ) and equivalent radius (FR) (p<0.01), less significant compactness (FF) and roundness (FC) (p<0.05). The discordance of development is established by a number of reliable values at the stage of late fetogenesis: the area of the tubule (p<0.01), the area of the epithelium of the preacinar department (p<0.001), the value of the outer perimeter of the tubule, the length and, to a lesser extent, the width of the tubule (p<0.05) significantly exceed such type II indicators. In this regard, the dimensions of X- and Y-projections for type I are also increased (p<0.05).Conclusion. As a result of morphological studies, the development of entodermal derivatives of pulmonary parenchyma at the pseudoglandular stage (day 14 of gestation) and the canalicular stage (day 20 of gestation) in rat fetus was verified; morphometric criteria for assessing the histogenesis of entodermal parenchyma units at critical stages of development have been introduced; comparative analysis of morphometric indices of different individuals in gestation dynamics; individual variants of two morphotypes are objectified – “compact-I” and “air-II” in the process of histogenesis of the fetal lungs.

Enhancement of circular RC columns using steel mesh as internal or external confinement under the influence of axial compression loading

Reinforced concrete (RC) columns cannot get supreme confinement by using the customary steel stirrups reinforcement because of the requirements for the spacing distances between the stirrups in addition to concrete continuance trouble. For this, Steel Mesh (SM) externally wrapped around the outer perimeter of the column as contributory confinement are being widely used due to its features. Limited tests focused on using SM for the internal confinement around the reinforcing cage of RC columns. Moreover, no experimental comparison was presented between RC columns internally and externally confined using SM. This paper investigates experimentally the behavior of circular RC columns confined internally or externally by SM. Six short RC columns have been subjected to axial loading until failure. The main studied parameters were SM schemes, number of SM wraps, SM position (internally or externally), and the steel stirrups existence. Results demonstrated that SM could decrease the crack opening, diminish the concrete spalling, increase the maximum failure load, and enhance the ductility, energy absorption, and column stiffness. Furthermore, the partially internal confinement using two wraps of SM around the steel ties presented the maximum capacity with reasonable ductility. In general, internally confined columns showed better behavior than the externally confined one.

Study on the Bond Strength of Steel-Concrete Composite Rectangular Fluted Sections

Concrete-filled steel tube (CFST) sections are structural members that effectively use the best properties of steel and concrete. Steel tube at the outer perimeter effectively resists tension and bending moments and also increases the stiffness of the section as steel has a high modulus of elasticity. The infilled concrete delays the local buckling of the thin outer steel tube. The interface bond strength plays a major role in the composite action of CFST sections. Provision of rectangular flutes on steel tube on CFST sections will improve the bond failure load and thereby the performance of CFST sections significantly. In this paper, the bond strength and displacement characteristics of steel-concrete composite sections are determined by incorporating rectangular shaped flutes into the steel tube. A total of five sections were tested to assess the influence of flutes on the bond strength. These tested sections are analyzed and are used to develop a finite element model using the finite element software ABAQUS version 6.13. The parameters chosen for the FE study are (i) type of flutes (outward and inward), (ii) D/t ratio (40, 60, and 80), (iii) number of flutes (2, 3, 4, 5, and 6), and (iv) dimension of flutes ((20 mm × 10 mm), (40 mm × 10 mm), and (60 mm × 10 mm)). Bond failure load is found to be higher for outward fluted sections compared to inward fluted and plain CFST sections.

Lithostratigraphy of the Mesoproterozoic Yas-Schuitdrift Batholith, South Africa and Namibia

The granitic and leucogranitic Yas and Schuitdrift Gneisses occur together as a large ovoid pre-tectonic batholith that crosses the Orange River border between South Africa and Namibia. They occur in the central parts of the Kakamas Domain in the Namaqua Sector of the Namaqua-Natal Metamorphic Province where they intrude, and are deformed together with, slightly older (~1.21 Ga) orthogneisses and granulite-facies metapelitic gneisses. The Yas Gneiss occurs mainly on the outer perimeter and northern parts of the batholith and comprises equigranular leucogranite gneiss and biotite granite augen orthogneiss, whereas the Schuitdrift biotite-hornblende augen gneiss is located at the centre and southern parts of the batholith. The batholith is strongly deformed with penetrative Namaqua-aged gneissic fabrics defined by grain-flattening of quartz and feldspar in the equigranular leucogneisses and aligned K-feldspar megacrysts in the augen gneisses. The gneissic fabric is refolded during a large-scale folding event that results in the dome-shape of the batholith and controls the present outcrop pattern of its various components. Flexure along the margins of the batholith refoliated the gneisses into a zone of mylonitic rocks. The Yas and Schuitdrift Gneisses have similar geochemistry and classify as alkali granites and alkali leucogranites. They are felsic (mean SiO2: 74.5 wt%) and potassic (mean K2O: 5.8 wt%) but have low MgO, CaO and Na2O, reflecting their low mafic mineral and plagioclase contents. The Schuitdrift Gneiss yielded U-Pb zircon ages of 1 191 ± 7 and 1 187 ± 6 Ma.

AMS Dates and the Chronology of Great Zimbabwe

Salvage excavations in the 1970s uncovered a sizeable commoner occupation at Great Zimbabwe, as well as evidence for the early construction of an elite stonewalled enclosure. As a result of these excavations, we can revise somewhat the chronology of Great Zimbabwe. The most important changes are the extension of Period IVa, lasting from AD 1285±10 to 1395±10, and the appearance of P, P/Q and Q-coursed walling in Period IVa. The small Nemanwa palace was built in P/Q and first dates to Period IVa, as does the Outer Perimeter Wall, and both were linked to the growth of the Zimbabwe state. Period IVb represents the floruit of Great Zimbabwe, while Period IVc encompasses the occupation after the political elite moved north to become the well-known Mutapa dynasty. After the move north, the Mutapa established a masungiro ritual centre at Great Zimbabwe, perhaps to maintain territorial rights in the face of Torwa expansion.

To substantiate the standard range of planning and technological solutions of farms for milk production

Annotation Purpose. Improving the efficiency of milk production by determining the rational standard size range of design technological solutions for the premises of farms for the content of dairy livestock. Methods. Theoretical provisions for the calculation of design and technological solutions for the construction of livestock buildings, we use graphical and graphoanalytical methods. Results. The design and technological schemes were considered of cowsheds with different placement of the number technological rows and grouping of stalls, for: a two-row scheme with a central aft passage; six-row layout of stalls (with a feed table along the outer perimeter and with a feed table in the center of the barn); 8-row layout of stalls in the barn with two feed tables.The cost of building a room of sandwich panels for a size range of 128 cows per cow is 20601 UAH against 25294 UAHconstructions of brick, which is 22% less than the cost while we have an increase in air volume per cow, respectively, 77 m3 vs. 55 m3 Conclusions 1. The rational standard size range of the milk production farm was determined: premises for 128 cows have 4 rows of 2 stall groups of 16 cows each; premises for 256 cows has 4 rows with 4 stall groups of 16 cows or 8 rows with 2 stall groups of 16 cows; premises for 384 cows has 8 rows with 3 stall groups of 16 cows each or 8 rows with 4 stall groups of 12 cows each; keeping 512 cows the premises has 8 rows of 4 stall groups of 16 cows. In accordance with technical and economic indicators, the most effective content is 386 (400) cows. 2. The economic effect is ensured by rational distribution of the size range of the stalls, their number, and the aisle size in accordance with the zoo-technical requirements for maintaining a highly productive livestock of cows for milk production farms and is 8–16% of the cost of construction and its subsequent maintenance, as a result, the area of the premises decreases for keeping cows and, accordingly, the amount of building materials. Keywords: stall, feed table, barn, stall section, feeding front, type-size range.

Microtubule Nucleation by Single Human γTuRC in a Partly Open Asymmetric Conformation

SUMMARYThe γ-tubulin ring complex (γTuRC) is the major microtubule nucleator in cells. However, the mechanism of its regulation is not understood. Here, we purified human γTuRC and quantitatively characterized its nucleation properties in a TIRF microscopy-based real-time nucleation assay. We find that microtubule nucleation by γTuRC is kinetically inhibited compared to microtubule elongation. Determining the cryo-EM structure of γTuRC at 4 Å resolution reveals an asymmetric conformation with only part of the complex in a ‘closed’ conformation matching the microtubule geometry. Several factors stabilise the closed conformation. One is actin in the core of the complex and others, likely MZT1 or MZT2, line the outer perimeter of the closed part of γTuRC. The opposed side of γTuRC is in an ‘open’, nucleation-incompetent conformation, leading to a structural asymmetry, explaining the kinetic inhibition of nucleation by human γTuRC. Our data suggest possible regulatory mechanisms for microtubule nucleation by γTuRC closure.

EXPERIMANTAL RESEARCHES OF THE CURRENT BURDENING COURSE PLATES ACHIEVEMENTS

The article presents the experimental study results of flat intercolumn plates loading work peculiarities of the beamless overlapping developed system. The attention is paid to the design of the experimental designs of the bearing structure with thebevelled platforms of suspension on the outer perimeter of the span plates. The technique of performing experimental studiesis presented. The conducted researches enabled to establish the nature of deformation and destruction of intercolumn plates asa separate element in the developed system of beamless overlapping. In this case, the magnitude of the compression deformations decreases to the point where the test specimens rest on the supporting blocks. It confirms the assumption of the transferof load from the spacers to the intercolumnar on the principle of "linear hinge". Attention is paid to the fact that the achievement of the bearing capacity is not accompanied by the process of destruction, but is characterized by significant movementsof the flying part of the plate in the vertical plane.

Performance of Outrigger System by Non-Linear Static Method

High rise building structures are highly affected by lateral loads and wind forces. To enhance lateral force outrigger systems are developed, which are one of the most popular and efficient, because they are easier to build and they provides good lateral stiffness. With the rise of building height, deep beam become concrete walls at least of one story height. Axial shortening effect between core and perimeter structure has to be considered.In the present work 20 story reinforced concrete structure has taken with outrigger walls attached from core to the outer perimeter column. By changing the different position of outrigger level are kept for analysis.The building without and with outrigger are compared with bareframe. These are different building models analysed (a) Bare frame of twenty story building (b) Bare frame with core shear wall building (c) Outrigger system at top of building (d) Outrigger system at top & 0.75 Height of building (e) Outrigger system at top & 0.50 Height of building (f) Outrigger system at top & 0.25 Height of building. Non-linear static analysis results were compared. The analytical methods used in the work are pushover method. In this work, various parameters like pushover curve, displacement vs base force, story displacement, hinges formation are obtained for all the models.Outrigger at optimum level at 0.5 Height gives better results in both displacements and base force. To sustain peak lateral loads these systems are provided half of the height. These study gives has inelastic behaviour of structure.