Section Of Wall Research Articles

ГРАФІЧНА РЕКОНСТРУКЦІЯ ОБОРОННОГО ВАЛУ СЛОВ’ЯНСЬКОГО ГОРОДИЩА ІІІ У МІСТІ КОРОСТЕНЬ (ЗА АРХЕОЛОГІЧНИМИ ДАНИМИ)

ГРАФІЧНА РЕКОНСТРУКЦІЯ ОБОРОННОГО ВАЛУ СЛОВ’ЯНСЬКОГО ГОРОДИЩА ІІІ У МІСТІ КОРОСТЕНЬ (ЗА АРХЕОЛОГІЧНИМИ ДАНИМИ)

Development of a method for determining the stability reserve of iron ore pit board section

The purpose of this article is to develop a new methodology for assessing the stability margin of iron ore opencast sides sections. The sequence of work. To achieve this goal, at the first stage, high-resolution photography was carried out for characteristic sections of the pit wall, followed by computer processing of photographs to assess the fracturing of rocks. The next step was the calculation of the fractal dimension of the array section from the obtained images using the ImageJ and FracLac programs, including the MicroMod2015 plug-in package (add-ons). The next step was assess the disturbance of the massif due to fracturing, a study of the relationship between the fractal dimension and the coefficient of structural weakening was carried out (this coefficient is determined by the classical method through the ratio of the strength of rocks in the massif and in the sample). At the last stage of the work, after establishing the specified connection and calculating the coefficient of structural weakening of rocks that based on the results of determining the fractal dimension, an assessment of the stability margin iron ore opencast sides sections that carried out. The known dependence of the stability safety factor on the coefficient of structural weakening of the array was used. As a result of comparing the fractal dimension of the exposed massif areas based on photographs with the calculation by classical methods, the discrepancy in the structural attenuation coefficient was 5-10%. This indicates a satisfactory convergence and allows the use of this express technique for assessing the fracturing of a section of a pit flank on the basis of fractal dimension. The scientific novelty of the results obtained - for the first time, the analytical dependence of the structural weakening coefficient of rocks on the fractal dimension of the massif cracks was established, which made it possible to simplify the procedure for its calculation. The practical significanceof the work lies in the creation of a new methodology for assessing the stability margin of an iron ore opencast side sections that the basis of rock fractures fractal analysis.

Comparative structural analysis of polyurethane and silicone catheters of totally implantable venous access devices by micro-computed tomography

Objectives:To investigate microstructural alterations of explanted long-term central venous catheters of totally implantable venous access devices, using micro-computed tomography.Methods:A total of 16 catheters (9 made of silicone and 7 made of polyurethane), all non-fractured, have been analyzed in this study. Eight catheters were implanted for an average duration of 994 days (min–max: 98–2731 days), while the remaining eight catheters (four for each material, forming the SIref and PUref control groups) were analyzed before implant and used as a reference. X-ray micro-computed tomography was used to reconstruct the three-dimensional geometry of selected segments of each catheter (ca. 10 cm per sample).Results:Morphometric analysis of the catheters revealed increases wall thickness and section area in the polyurethane group as compared with the reference central venous catheters of the same materials (wall thickness: 403 ± 12 μm in the polyurethane (PU) group vs 382 ± 4 μm in PUref, p = 0.014; wall cross-section area: 2.04 ± 0.09 mm2 in PU vs 1.91 ± 0.03 mm2 in PUref, p = 0.04), whereas implanted silicone catheters showed a larger luminal cross section as compared with their controls (lumen cross-section area = 0.851 ± 0.020 mm2 in silicone (SI) group vs 0.811 ± 0.007 mm2 in SIref, p = 0.007). All analyzed samples in this study presented some type of alteration in the catheter walls, namely, hyperdense spots (below 0.1 mm size), air gaps/bubbles and displacements of inner and outer axes causing heterogeneous wall thickness. The incidence of air gaps showed no difference with respect to both material type and duration of implant, whereas the SI group revealed more hyperdense spots as compared to all other groups.Conclusion:Morphological change and local structural alteration can occur in both silicone and polyurethane catheters. This evidence suggests the need for further studies connecting those morphological changes with modification of mechanical robustness, which ultimately can play a role for patient safety.

Study on optimization design of roadway cross-section form in Xinyu mine

The stability of roadway is of great significance to mine safety production. In this paper, according to the geological conditions of Xinyu coal mine, the cross-section form of track roadway is optimized. Under the condition of the same ratio of height to width, rectangular section, circular arch section and straight wall semicircular arch section are designed respectively. FLAC3D is used to establish numerical model to simulate three kinds of section forms. The optimal section form is obtained by analyzing displacement field, plastic zone distribution and stress field. The results show that: (1) The cross-section form of coal mine roadway is an important factor affecting the stability of roadway. (2) Under the same ratio of height to width, the stability of roadway from high to low is straight wall semicircular arch, circular arch and rectangle. (3) The field test data show that the straight wall semicircular arch roadway has good engineering effect. (4) Comprehensive comparison shows that the straight wall semicircle arch is the best roadway section form. The research results can provide reference for the design of roadway section form in the future.

Discussion on the optimum configuration of section steel for the middle seismic tensile stress of the shear wall of an over-limit high-rise civil building

A super high-rise civil building was originally designed with a relatively large area of shear wall section steel configuration, coupled with the configuration of steel bars, resulting in the construction of the project more difficult. To solve this problem, PKPM was used to build the model to extract and calculate the tensile stress of inflexible wall limbs under moderate earthquakes, and the configuration of the section steel in the original design was analyzed. An in-depth interpretation of the “Technical Points for Special Examination of Seismic Fortification of High-rise Buildings Exceeding Limits” (Jianzhi [2015] No. 67), Chapter 4, Article 12, Paragraph 4, on the provision of shear wall section steel configuration was conducted. Finally, based on the original design, an optimization criterion for the configuration of the section steel in the wall was proposed.

Application of the Darcy and Richards equations for modelling of water capillary rise in building materials

This paper presents the application of the Darcy and Richards equations, describing water flow and dynamic changes of the water content in porous medium, for numerical modeling of water capillary rise in the selected building materials. The numerical simulations of unsaturated and variably saturated water flow in the studied materials were performed in FEFLOW commercial computational software, by DHI-Wasy, Germany. The developed model represented a wall section constructed of aerated concrete blocks, covered by mortar prepared using blended cement with biomass ash addition. The physical and water retention characteristics of the modeled materials were based on the previously performed laboratory measurements and literature research. The assumed initial conditions reflected air dry wall with limited moisture, while the boundary conditions allowed modeling of capillary rise due to direct contact of the studied materials with water with variable pressure head. The results of numerical calculations allowed observation of the time-dependent changes in the moisture content of building materials in relation to their physical properties and variable boundary conditions.

Methods of the wall interference reduction at low supersonic velocities in wind tunnels

The paper describes the research aimed at reducing wall interference in wind tunnels at low supersonic velocities. The results of such wind tunnel tests are often affected by wave perturbations generated by the model and reflected from the test section walls. This research describes the methods that can effectively reduce the wave reflection from the wall. A numerical investigation is presented that includes a novel boundary condition that eliminates disadvantages of previously considered methods. The numerical study was conducted in the frame of electronic wind tunnel concept and ANSYS CFX software. The numerical investigation showed that the effect of shock wave reflection could be reduced using a new type of boundary condition that is a combination of perforated walls and a controlled boundary layer.

X-Ray Imaging Calibration for Fuel-Coolant Interaction Experimental Facilities

During a severe accident in either sodium-cooled or water-cooled nuclear reactors, jets of molten nuclear fuel may impinge on the coolant resulting in fuel-coolant interactions (FCI). Experimental programs are being conducted to study this phenomenology and to support the development of severe accident models. Due to the optical opacity of the test section walls, sodium coolant, and the apparent optical opacity of water in the presence of intense ebullition, high-speed X-ray imaging is the preferred technique for FCI visualization. The configuration of these X-ray imaging systems, whereby the test section is installed between a fan-beam X-ray source and a scintillator-image intensifier projecting an image in the visual spectrum onto a high-speed camera, entails certain imaging artefacts and uncertainties. The X-ray imaging configuration requires precise calibration to enable detailed quantitative characterization of the FCI. To this end, ‘phantom’ models have been fabricated using polyethylene, either steel or hafnia powder, and empty cavities to represent sodium, molten fuel and sodium vapor phases respectively. A checkerboard configuration of the phantom enables calibration and correction for lens distortion artefacts which magnify features towards the edge of the field of view. Polydisperse steel ball configurations enable precise determination of the lower limit of detection and the estimation of parallax errors which introduce uncertainty in an object’s silhouette dimensions. Calibration experiments at the MELT facility determined lower limits of detection in the order of 4 mm for steel spheres, and 1.7-3.75 mm for vapor films around a molten jet.

The results of a new approach to the method of modeling experimental postoperative peritonitis

Purpose: to develop a new, as close as possible to clinical conditions method of experimental modeling of postoperative peritonitis.Materials and methods. In the experiment we use 60 rats Vistar line, weighing 160-240 g, kept in a vivarium in compliance with all standards. General clinical and biochemical studies were conducted in the laboratory of the Department of Biological and Medical Chemistry of Ivano-Frankivsk National Medical University.Research results and their discussion. The method of experimental modeling of postoperative peritonitis developed by us is performed in sterile operating conditions. General anesthesia was performed by intramuscular injection of 0.15 ml per100 g of sodium oxybutyrate. After processing of the operating field, we performe an upper median laparotomy, a loop of the small intestine is removed into the wound, a purse string suture is applied to its wall, a cross section of the intestinal wall is made in the middle of the purse, and purse sutures are removed to the anterior abdominal wall. The node was then tied to the skin1.0 cm to the left of the median wound, sutured to the postoperative wound, and treated with betadine solution. The next day, the purse string suture dissolves and the contents of the intestine enter the abdominal cavity, causing postoperative peritonitis, which is as close as possible to clinical conditions and allow to avoid relaparotomy. With the help of a purse string suture, we avoided relaparotomy.

Model of Complex Heat Transfer in the Package of Rectangular Steel Sections

During heat treatment of rectangular steel sections, a heated charge in the form of regularly arranged packages is placed in a furnace. The article presents a model of a complex heat transfer in such a package using the thermo-electric analogy. The model considers the following types of heat transfer: conduction in section walls, conduction and natural convection within gas, heat radiation between the walls of a section, as well as contact conduction between the adjacent sections. The results of our own experimental research were used for calculations of heat resistance applying to natural convection and contact conduction. We assumed that the material of sections was low-carbon steel and the gas was air. The result of the calculations of the presented model is total thermal resistance Rto. The calculations were performed for the temperature range 20–700 °C for four geometrical cases. Due to the variability of conditions for contact heat conduction, we assumed that total thermal resistance for a given charge is contained within a value range between Rto-min and Rto-max. We established that the value of Rto depends significantly on the section’s geometry. The larger the section sizes, the greater the changes of Rto. The minimal and maximal values of Rto for all packages were 0.0051 (m2·K)/W and 0.0238 (m2·K)/W, respectively. The correctness of model calculations was verified with the use of experimental data.

Мікроструктура підслизового нервового сплетення кишечника качок

There are presented the results of the experimental research of the histological structure of the submucosal nerve plexuses in the intestines of domestic ducks (Anas platyrhynchos domesticus) of 9 age groups from diurnal to 1-year-old of the black White-Breasted breed. The definitions of topography, number, ganglia area, as well as density of neurons in them were determined on cross sections of the duodenum, jejunum, ileum, cecum and rectum. It is defined the nerve nodes and submucosal strands belonging to the enteric nervous system are located between the lamina muscularis mucosae and the inner layer of muscular tunic. In the cross section of the intestinal wall, the submucosal ganglia have the shape of narrow strips. In order to generalize the morphofunctional state of the nerve plexuses, there were determined two parameters: the average age indicator (AAI) of the intestine and intestine. AAI of a certain structure of each intestine was determined as the arithmetic mean of the values of its 9 age indicators. The AAI of a particular intestinal structure was determined as the arithmetic mean of the AAI quantities of the structure of all five intestines. The average number of submucosal ganglia did not increase with the age of the ducks, but changed with varying degrees of reliability in comparison with the previous age. In the intestines of diurnal to 1-day – 1-year-old ducks, the smallest number of submucosal ganglia was found in the cecum, and the largest was found in the rectum. The general pattern of the size dynamics of the submucosal ganglia in the intestines of ducks is an increase with age in their average area. There was found the smallest area of submucosal ganglia in the ileum in the group of ducks of different ages, and the largest was found in the duodenum and cecum. The lowest density of neurons in the submucosal ganglia is found in the cecum, the highest was found in the rectum. Changes in the morphometric parameters of the nerve plexuses ganglia in the intestines of ducks indicate the dynamic nature of changes in the morphofunctional state of the enteric nervous system.

QUALITY ASSURANCE OF DIAPHRAGM AND PILE WALLS BY GEOPHYSICS

Underground structures like diaphragm and pile walls are constructed to organize waterproof curtains, protect pit sides, and transfer loads from the structures. Violations of the construction technological process can lead to the formation of defects. To prevent adverse consequences, before excavation, it is necessary to control the integrity of the slurry walls using non-destructive geophysical methods. A review of geophysical slurry wall quality control methods based on the excitation and registration of physical fields through access tubes installed in the reinforcement cage, in wells drilled near the structure or on the surface of the structure, is presented. The main capabilities and limitations of the methods are given. Cross-hole ultrasonic logging was used to study the section of the slurry wall during the construction of the Moscow Metro station. The results of parallel soundings made it possible to identify anomalous zones, interpreted as defects. The geometric dimensions of one of the major defects were refined by ultrasonic tomography. For the first time in Russian testing practice, thermal integrity profiling was applied to study the diaphragm wall at the base of a residential building. The results of temperature monitoring during the concrete hardening are presented. According to the method, a major flaw, excess of the design mark of the wall bottom and bulging of the structure were revealed. The results of thermal integrity profiling were verified by ultrasonic logging. The combined use of thermal and ultrasonic methods can be recommended as a reliable tool for integrity testing of diaphragm and pile walls. To carry out the measurements, the access tubes shall be included in the reinforcement cage of the structure at the design stage.

Dual row retaining walls in dry sand: influence of wall stiffness on seismic response

Dual row retaining walls can form efficient port and embankment structures, or even be used as coastal defence against tsunamis. The system of parallel sheet pile walls can have a large lateral capacity within serviceability limit states due to the combined strength and stiffness of the walls and confined soil. Optimising the design by reducing the wall section and ensuring greater utilisation of the soil capacity has economic and environmental benefits but requires a deeper understanding of the dynamic soil–structure interaction. Centrifuge modelling and numerical modelling are used to elucidate the mechanics of two systems with relatively flexible and stiff walls. Considering the fraction of the wall’s plastic moment capacity mobilised alongside the peak deflections illustrates the advantages of using relatively flexible retaining walls in these systems. More fundamentally, the importance of vertical variations of both the stress and strain during the horizontal dynamic loading is shown. The limiting horizontal stresses and phasing of the stress components around the walls are better understood by considering the mobilisation of earth pressure coefficients, reinforcing previous work that recommends a move away from conventionally defined limiting dynamic earth pressure coefficients.

Previous flight facilitates partner finding in female crickets

In the cricket Gryllus bimaculatus, flying occurs soon after the last imaginal molt and precedes the mating behavior in natural conditions. Here, we tested the hypothesis that flying may improve subsequent behavioral performance in a novel environment in female crickets. We developed a behavioral set-up to test female cricket responsiveness to male calling song as well as their ability to locate and find the source of the song. The male song was produced by a loudspeaker hidden behind the fabric wall of a spacious square arena. Forced flight prior to the test promoted female sexual searching behavior in the novel environment. After the flight, more females reached the hidden source zone, spent more time near the source and finally more of them climbed over the wall section immediately in front of the hidden loudspeaker. At the same time, their behavior in the arena did not differ from the control group when the calling song was not delivered, suggesting that flight exerts its behavioral effects by influencing sexual motivation. Our results support the suggestion that preceding intense locomotion facilitates sexual searching behavior of females in a novel environment.

166 Altering the ruminal microbiota in dairy calves using rumen contents dosing

Abstract A major goal in dairy research is to improve milk production efficiency (MPE). With the advent of next-generation sequencing, efforts are underway to improve MPE by manipulating the rumen microbiota. MPE correlates to ruminal bacterial community composition (BCC), but the adult rumen microbiota is highly stable and returns to a baseline BCC after heavy perturbation. We seek to influence rumen BCC by early intervention in pre-weaning calves. Two cannulated Holstein donors of disparate MPE were selected. Three cohorts of 6 bull calves were established and dosed by gavage with a rumen inoculum sourced from the high-efficiency donor (HE), the low-efficiency donor (LE), or an autoclaved 50:50 mix as a microbe-free control (C). Dosing occurred at birth, then biweekly through 6 weeks. Feces were collected at each dosing. Daily preweaning intake of calf starter, which correlates to downstream feed efficiency, was greatest in HE calves and lowest in C calves (P < 0.05), though preweaning average daily gain did not differ between cohorts (P = 0.210). Calves were sacrificed at 8 weeks to access rumen contents and rumen wall sections were collected to assess papillation. Fecal and rumen samples were subjected to 16S rRNA amplicon sequencing. BCC differed by cohort in fecal and rumen samples (P < 0.05), with HE calf samples most similar to adult rumen samples and C calves least similar. Additionally, HE calves tended to have elongated papillae (P =0.062), the development of which is dependent on byproducts of microbial metabolism in the rumen and which points to differences in potential absorptive capacity of the epithelium. These data demonstrate that the rumen BCC can be influenced by early intervention. Future work includes expansion of this dosing protocol to a cohort of 60 female calves, following rumen BCC development and the impact on MPE in through the first lactation.

Experimental study of post-CHF heat transfer in a vertical tubular test section

In this paper, post-CHF (critical heat flux) experiments are performed in a vertical tubular test section with water as the working fluid to study the heat transfer characteristics during the process of formation, growth, and propagation of dry patches. The formation, growth, and propagation of the dry patches are indicated from the measured wall temperatures of the test section. The so-called dry temperature and quench temperature, corresponding to the formation and departure of dry patches, are obtained by analyzing the first-order derivative of the measured wall temperatures. The temperature gradient along the axial direction of the test section wall is also calculated, up to 15 °C/mm. Large temperature gradients result in axial heat conduction as well as thermal stresses in the test section. The convective heat transfer coefficient for the dry patches is calculated based on the saturation temperature of the fluid and compared with three heat transfer correlations in the literature. The computed convective heat transfer coefficient for the dry patches in our experiments is larger than the calculated results of the correlations, especially for conditions of relatively low wall superheats.

In Situ Monitoring of Drying Process of Masonry Walls

The in situ hygro-thermal behavior of a wet masonry wall during its drying process is presented in this paper. The considered wall is a part of a basement of a historic building that was subjected to renovation works. The building is located in the City of Łowicz (Poland). The drying process was implemented by applying the thermo-injection method and a novel prototype of the drying device used for this method. The dedicated acquisition system was developed to in situ monitor parameters of the drying process. The air temperature and relative humidity in various locations in the basement, temperatures and moisture contents at several points of the wet wall as well as the electrical parameters of the drying device were registered. Based on variations of the monitored parameters, the hygro-thermal behavior of the wall during drying was studied. After 6 days of drying, the wall temperature in the drying zone was increased to approximately 40–55 °C, while the moisture content was reduced to the mean level of 3.76% vol. (2.35% wt.). These wall parameters allowed for effective impregnation of the wall with the hydrophobic silicone micro-emulsion, which created horizontal and vertical waterproofing. Moreover, the specific energy consumption during the drying process defined as energy consumption divided by the mean volumetric moisture content drop (MC) between the initial and final state in the wall and by the length of the dried wall section was estimated to be 11.08 kWh/MC%/m.

La piedra en seco en la Sierra de Tramuntana, Mallorca: Un ejemplo de obra pública moderna

El conjunto de construcciones de piedra en seco en Mallorca es extenso y variado. En el año 2011 fue reconocido por la UNESCO como Patrimonio de la Humanidad en calidad de Paisaje Cultural. La piedra en seco es un oficio altamente especializado, un saber acumulado que ha sido transmitido a través de generaciones y que afortunadamente ha continuado vivo hasta nuestros días. Durante el mes de febrero del año 2019, tras unas intensas lluvias, un tramo del muro que sostiene la red viaria colapsó, y con él la carretera que sostenía. El Gremi de Margers de Mallorca, la asociación de constructores profesionales de piedra en seco de la isla, urgió a la Administración a llevar a cabo una restauración de la obra que fuera respetuosa con las técnicas originalmente utilizadas, proponiendo la reconstrucción del muro en seco tal y como era.

Histomorphological changes in baker’s cyst tissues associated with the duration of one-directional thermal exposure

AIM: To identify and describe micro- and ultrastructural thermally induced changes in Bakers cyst wall associated with the duration of unidirectional uniform heating at 70C.
 MATERIALS AND METHODS: We took one full-thickness fragment from each of the 15 Bakers cysts excised during the operation and divided each fragment into four parts: one was used as a control sample, and the remaining three fragments were placed with the synovial membrane on a thermostat heated to 70C, with exposure times of 60, 120, and 180 seconds. We used light-optical and electron microscopes for the histomorphological examination of the samples.
 RESULTS: Two layers of Bakers cyst wall were identified: inner (synovial) and outer (fibrous). In samples exposed to heat for 60 seconds, the synovial layer was undamaged. In samples exposed to heat for 120 seconds, thermal damage to the cells of the synovial layer and underlying collagen fibers of the fibrous layer was evident. With a heating duration of up to 180 seconds, histomorphological examination revealed signs of damage reaching the middle of the fibrous layer, and signs of deep disorganization of the collagen fibers of the cyst wall were determined at the electron-microscopic level.
 DISCUSSION: Using light microscopy of intact sections of the cyst wall, we, like other researchers, identified two layers (synovial and fibrous) of different densities, with blood vessels passing through them. The performed experiment suggests that a clinically significant result using Bakers cyst thermotherapy is achieved when spreading the zone of irreversible coagulation beyond the middle of the fibrous layer of the cyst wall. This, in turn, guarantees damage to the capillary network that provides trophism and proliferation of synoviocytes. The proposed hypothesis corresponds to the paradigm of similar studies on the coagulation of cysts of other localizations.
 CONCLUSION: The obtained results of the light-optical and electron-microscopic examination of Bakers cyst wall fragments indicate direct dependence of the depth of thermal coagulation on the duration of heating.

Atomic Force Microscopy to Study Cell Wall Mechanics in Plants.

Atomic force microscopy (AFM) is an indentation technique used to reconstruct the topography of various materials and organisms. AFM can also measure the mechanical properties of the sample. In plants, AFM is applied to image cell wall structural details and measure the elastic properties in the outer cell walls. Here, I describe the use of high-resolution AFM to measure the elasticity of resin-embedded ultrathin sections of leaf epidermal cell walls. This approach allows to access the fine details within the wall matrix and eliminate the influence of the topography or the turgor on mechanical measurements. In this chapter, the sample preparation, AFM image acquisition, and processing of force curves are described. Altogether, these methods allow to measure the wall stiffness and compare different cell wall regions.