scholarly journals On the formation of a waterproofing shell around the underground structure lining in watered ground

2021 ◽  
Vol 315 ◽  
pp. 02005
Author(s):  
Andrey Uglyanitsa
Keyword(s):  
Outer Surface ◽  
Cement Mortar ◽  
Underground Structure ◽  
Injection Pressure ◽  
Soil Mass ◽  
Separation Process ◽  
Optimal Parameters ◽  
Reduced Water ◽  
Underground Method ◽  
Incipient Crack

To prevent the filtration of groundwater into the used underground structure in operation through its lining, it is proposed to make two waterproofing shells by the underground method around the outer surface of the lining of an underground structure; the upper one is made of the soil mass compacted by cementation with reduced water permeability and the lower one is made of the silicate cement. To make the upper shell, boreholes are drilled from an underground structure through its lining and the cement mortar is alternately injected through them into the watered ground providing its hydraulic fracturing; and to make the lower shell, injection pipes with a diameter of 102-152 mm are installed between the boreholes in the lining flush with its outer surface, the silicate cement mortar is alternately injected into the injection pipes, an incipient crack is created between the outer surface of the lining and the ground under the action of the mortar injection pressure on the ground opposite the injection pipe, an incipient crack is hydraulically extended along the contact of the lining with the ground and filled with the silicate cement mortar until refusal to absorb it. To determine the optimal parameters of the hydraulic separation process, tests were carried out on the laboratory table simulator.

scholarly journals Effect of TiO2Nanoliquid on the Properties of Cement Mortar

2018 ◽  
Vol 7 (3.12) ◽  
pp. 223
Author(s):  
C Prabalini ◽  
Z Aysha Farsana ◽  
A Sumathi
Keyword(s):  
Outer Surface ◽  
Cement Mortar ◽  
Heat Of Hydration ◽  
New Methods ◽  
Curing Period ◽  
Lime Water ◽  
To Come ◽  
Strength And Durability

Mortar/Concrete is effectively used in the construction of buildings. In the view of developing the infrastructure, it is essential to come up with new methods. Generally, the mortar which is being used has numerous pores in it and thus the strength gets reduced and the absorption increases. To reduce the durability problems nano liquid is being added. Nano liquid has the advantages of anti microbial and anti UV action. This paper deals with the nano liquid on the properties of cement mortar with two curing medium (water and saturated lime water) for 3, 7 and 28 days and the results were compared with control mortar in terms of strength and durability. Nano liquid was added in terms of 2.5ml, 5ml, and 7.5ml per kg of cement. After the completion of curing period the nano liquid is uniformly sprayed on the outer surface of the mortar cube. Since the nano liquid emits heat, the curing is made with lime to reduce the heat of hydration.  

scholarly journals A new method for calculating the combined anchor-concrete support of underground structures

2018 ◽  
Vol 170 ◽  
pp. 03023 ◽  
Author(s):  
Mikhail Pleshko ◽  
Besarion Meskhi ◽  
Marianna Pleshko
Keyword(s):  
Negative Impact ◽  
Tensile Force ◽  
Underground Structure ◽  
Soil Mass ◽  
Regulatory Elements ◽  
New Method ◽  
Underground Structures ◽  
Emergency Situations ◽  
Tensile Forces ◽  
Surrounding Soil

The problematic aspect of the underground structures construction in the urban area is the negative impact of construction on neighboring buildings and structures. To exclude emergency situations, it is required to control the interaction of the support of the underground structure and the surrounding soil mass by including additional regulatory elements, such as anchors, in the system. The article presents a new method for calculating the anchor-concrete support of underground structures and the results of monitoring of tensile forces in the bolting. It has been established that the tensile force has the highest constant value at the well mouth - jointing of the anchor rod, and then decrease exponentially.

Geotechnical synthesis of 2D_Electrical resistivity tomography of geomaterial_laboratory model study

2011 ◽  
Vol 8 (1) ◽  
pp. 1
Author(s):  
Zainab Mohamed ◽  
Nurbaiyah Mohamad Noh
Keyword(s):  
Electrical Resistivity ◽  
Cement Mortar ◽  
Clay Fraction ◽  
Soil Mass ◽  
Mass Scale ◽  
Scale Model ◽  
Hard Material ◽  
Residual Soil ◽  
Hard Layer ◽  
Model Study

In this paper, a laboratory scale model study was conducted on interbeded geomaterial using electrical resistivity instrument. The electrical resistivity value of individual material was determined and modeled as mass scale. The tank was filled with composite geomaterial constituted of interbedding of cement mortar as hard layer and residual sedimentary soil. Forty-one copper electrodes of 15 cm long were used and installed at 4 cm spacing in the tank. The composite geomaterials were labeled as Model 1, Model 2 and Model 3, where they were referred respectively to interbedding of hard layer and layers of residual soil at natural dry state and wet state. The electrical resistivity terrameter was used to obtain the georesistivity pseudo-section by adopting Werner protocol. The georesistivity pseudo-sections were derived from 3 models simulated the subsurface of rock mass in humid tropic environment. The objective was to synthesize the composite georesistivity pseudo-section based on geo-engineering principle. It was observed that the pseudo-section of the composite geomaterial was represented by range of colors with range of georesistivity values. The horizontal bands of color differentiated the georesistivity of models vertically but constant in horizontal direction. The georesistivity value at material scale was comparable to the range of georesistivity values derived from the 2D electrical resistivity pseudo-sections. The contrasts in the conductivity of clay fraction, silica and electrolytes have differentiated the electrical resistivity pseudo-section of sandy soil mass and cement mortar hard material.

scholarly journals Konkurencyjność polskich odmian orzechów laskowych w zależności od ich jakości określonej właściwościami fizykochemicznymi

2017 ◽  
pp. 127-138
Author(s):  
Magdalena Gantner ◽  
Eugenia Czernyszewicz ◽  
Klaudia Kopczyńska ◽  
Katarzyna Król
Keyword(s):  
Water Activity ◽  
Plant Material ◽  
Main Parameter ◽  
Optimal Parameters ◽  
Browning Index ◽  
Roasting Process ◽  
Processing Properties ◽  
Reduced Water ◽  
Selection Of

The aim of the study is to compare the quality of hazelnuts grown in Poland in opposition to imported ones, based on their changes in physicochemical properties depending on the roasting parameters. The plant material was two hazelnuts cultivars grown in Poland: ‘Olbrzym z Halle’ and ‘Cosford’. The samples were roasted at nine specific temperatures and time conditions: at 110°C, 130°C and 160°C, each at 15, 30 and 60 min. Parameters such as water activity, color of the inner (brown) skin of the husk and color of the pure kernel’s surface and hardness were investigated. The roasting process reduced water activity, decreased luminosity (L*) of kernel hazelnuts irrespective of cultivar and increased browning index (BI) value. The main parameter determining these changes was temperature. In addition, as the process temperature increased the hardness of the nuts and their structure became more fragile and delicate. Nuts of ‘Cosford’ cultivar were characterized by higher hardness compared to the nuts of ‘Olbrzym z Halle’ cultivar. The temperature of 130° for 30 min provided the best quality of the roasted nuts, regardless of the cultivar. Nuts of both cultivars, roasted in these parameters were characterized by comparable, high ease of removal of the brown inner skin. The selection of optimal parameters of technological process can improve the processing properties of Polish hazelnuts and, consequently, ensure their competitive advantage against nuts grown in other countries. This fact could increase both the chance of their export as well as the use in Polish confectionery production.

scholarly journals Influence of acid treatment and carbonation on the properties of recycled concrete aggregate

2018 ◽  
Vol 24 (1) ◽  
pp. 23-30 ◽  
Author(s):  
Aleksandar Radevic ◽  
Iva Despotovic ◽  
Dimitrije Zakic ◽  
Marko Oreskovic ◽  
Dragica Jevtic
Keyword(s):  
Quality Improvement ◽  
Water Absorption ◽  
Acid Treatment ◽  
Cement Mortar ◽  
Recycled Concrete ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Accelerated Carbonation ◽  
Natural Aggregate ◽  
Reduced Water

Recycled concrete aggregate (RCA), obtained by crushing of original (old) concrete, consists of natural aggregate grains and a cement mortar matrix. The presence of old adhered cement mortar, which has higher porosity than natural aggregate, causes unfavourable properties of RCA. The research conducted in order to improve the quality of RCA and to enable its greater application in the construction industry is presented in this paper. Therefore, RCA was subjected to quality improvement treatments with hydrochloric acid and carbon dioxide (accelerated carbonation). The first procedure was aimed at partially removing the adhered cement mortar and the second at reinforcing the cement matrix. The physical, mechanical and chemical properties of all three types of RCA were tested. After the pre-soaking acid treatment (0.1 mol/dm3 HCl), RCA showed reduced water absorption (up to 3%); the process of accelerated carbonation also led to reduced water absorption (13?20%) as well as to improved mechanical properties (?10%). A scanning electron microscopy investigation revealed that the carbonation process, as expected, significantly reduces porosity of RCA. The overall results show that if RCA is obtained by crushing of compact, high- -quality concrete, the procedures of aggregate quality improvement are not necessary.

scholarly journals MODELING OF BLAST EFFECTS ON UNDERGROUND STRUCTURE

2019 ◽  
Vol 15 (4) ◽  
pp. 111-122
Author(s):  
Oleg Mkrtychev ◽  
Anton Savenkov
Keyword(s):  
Shock Wave ◽  
Nonlinear Dynamic ◽  
Underground Structure ◽  
Ground Surface ◽  
Soil Mass ◽  
Point Explosion ◽  
Coupled Numerical Model ◽  
Blast Effects ◽  
Dynamic Formulation ◽  
The Impact

Modeling of the impact of a point explosion shock wave on a soil mass and an underground structure at different locations of the explosion epicenter from the ground surface was performed. The study of the stress- strain state of soils was carried out usi ng a nonlinear dynamic method and a fully coupled numerical model, in­cluding various models of materials. The result of numerical modeling showed the adequacy of the adopted nu­merical calculation methods. The findings showed that solving the problem in a nonlinear dynamic formulation allows obtaining the parameters of the shock wave at different depths from the explosion center, as well as ob­taining a complete picture of the interaction of the shock wave with the underground structure in surface and un­derground explosions.

A scanning electron microscopic study on dissolving process of cholesterol gallstones by chenodeoxycholic acid (CDCA)

1978 ◽  
Vol 36 (2) ◽  
pp. 522-523
Author(s):  
T. Kanetaka ◽  
M. Cho ◽  
S. Kawamura ◽  
T. Sado ◽  
K. Hara
Keyword(s):  
Electron Microscope ◽  
Chenodeoxycholic Acid ◽  
Outer Surface ◽  
Electron Microscopic ◽  
Cholesterol Gallstones ◽  
The Core ◽  
Scanning Electron Microscopic Study ◽  
Scanning Electron Microscopic ◽  
Acceleration Voltage ◽  
Scanning Electron

The authors have investigated the dissolution process of human cholesterol gallstones using a scanning electron microscope(SEM). This study was carried out by comparing control gallstones incubated in beagle bile with gallstones obtained from patients who were treated with chenodeoxycholic acid(CDCA).The cholesterol gallstones for this study were obtained from 14 patients. Three control patients were treated without CDCA and eleven patients were treated with CDCA 300-600 mg/day for periods ranging from four to twenty five months. It was confirmed through chemical analysis that these gallstones contained more than 80% cholesterol in both the outer surface and the core.The specimen were obtained from the outer surface and the core of the gallstones. Each specimen was attached to alminum sheet and coated with carbon to 100Å thickness. The SEM observation was made by Hitachi S-550 with 20 kV acceleration voltage and with 60-20, 000X magnification.

A SEM and Light Microscope Study of the Epidermal Leaf Structures of the Carnivorous Plant, Sarracenia purpurea, L.

1971 ◽  
Vol 29 ◽  
pp. 358-359
Author(s):  
B. J. Panessa ◽  
J. F. Gennaro
Keyword(s):  
Methylene Blue ◽  
Toluidine Blue ◽  
Outer Surface ◽  
Microscope Study ◽  
Light Microscope ◽  
Carnivorous Plant ◽  
Sarracenia Purpurea ◽  
Inner Surface

Tissue from the hood and sarcophagus regions were fixed in 6% glutaraldehyde in 1 M.cacodylate buffer and washed in buffer. Tissue for SEM was partially dried, attached to aluminium targets with silver conducting paint, carbon-gold coated(100-500Å), and examined in a Kent Cambridge Stereoscan S4. Tissue for the light microscope was post fixed in 1% aqueous OsO4, dehydrated in acetone (4°C), embedded in Epon 812 and sectioned at ½u on a Sorvall MT 2 ultramicrotome. Cross and longitudinal sections were cut and stained with PAS, 0.5% toluidine blue and 1% azure II-methylene blue. Measurements were made from both SEM and Light micrographs.The tissue had two structurally distinct surfaces, an outer surface with small (225-500 µ) pubescent hairs (12/mm2), numerous stoma (77/mm2), and nectar glands(8/mm2); and an inner surface with large (784-1000 µ)stiff hairs(4/mm2), fewer stoma (46/mm2) and larger, more complex glands(16/mm2), presumably of a digestive nature.

Cristal-growth dynamics of n-doped gaAs

1992 ◽  
Vol 50 (2) ◽  
pp. 1544-1545
Author(s):  
Pham V. Huong ◽  
Stéphanie Bouchet ◽  
Jean-Claude Launay
Keyword(s):  
Crystal Growth ◽  
Spatial Resolution ◽  
Epitaxial Layer ◽  
Outer Surface ◽  
Gaas Substrate ◽  
Structural Modification ◽  
Growth Dynamics ◽  
Argon Laser ◽  
High Anisotropy ◽  
Crystal Gaas

Microstructure of epitaxial layers of doped GaAs and its crystal growth dynamics on single crystal GaAs substrate were studied by Raman microspectroscopy with a Dilor OMARS instrument equipped with a 1024 photodiode multichannel detector and a ion-argon laser Spectra-Physics emitting at 514.5 nm.The spatial resolution of this technique, less than 1 μm2, allows the recording of Raman spectra at several spots in function of thickness, from the substrate to the outer deposit, including areas around the interface (Fig.l).The high anisotropy of the LO and TO Raman bands is indicative of the orientation of the epitaxial layer as well as of the structural modification in the deposit and in the substrate at the interface.With Sn doped, the epitaxial layer also presents plasmon in Raman scattering. This fact is already very well known, but we additionally observed that its frequency increases with the thickness of the deposit. For a sample with electron density 1020 cm-3, the plasmon L+ appears at 930 and 790 cm-1 near the outer surface.

High spatial resolution AEM observations of yttrium segregation in chromia scales grown on Co-45%Cr

1986 ◽  
Vol 44 ◽  
pp. 518-519
Author(s):  
K. Przybylski ◽  
A. J. Garratt-Reed ◽  
G. J. Yurek
Keyword(s):  
Spatial Resolution ◽  
Outer Surface ◽  
Maximum Concentration ◽  
High Spatial Resolution ◽  
Reactive Elements ◽  
Chromia Scales

The addition of so-called “reactive” elements such as yttrium to alloys is known to enhance the protective nature of Cr2O3 or Al2O3 scales. However, the mechanism by which this enhancement is achieved remains unclear. An A.E.M. study has been performed of scales grown at 1000°C for 25 hr. in pure O2 on Co-45%Cr implanted at 70 keV with 2x1016 atoms/cm2 of yttrium. In the unoxidized alloys it was calculated that the maximum concentration of Y was 13.9 wt% at a depth of about 17 nm. SIMS results showed that in the scale the yttrium remained near the outer surface.

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