scholarly journals Delineation of Cavity in Downstream Surge Chamber at Punatsangchhu-II Hydroelectric Project, Bhutan

2019 ◽  
Vol 1 (1) ◽  
Author(s):  
Siva Prasad BNV
Keyword(s):  
Cavity Formation ◽  
Seismic Surveys ◽  
Hydroelectric Project ◽  
Roof Fall ◽  
Treatment Measures ◽  
Exploratory Drilling

On 3rd March, 2016, there occurred a massive roof fall incidence in one of the major caverns of Punatsangchhu-II Hydroelectric Project (PHEP-II), Bhutan which halted the operations in the major caverns and required additional strengthening measures. Prior to concluding anything on the treatment measures for the muck flown into the cavern and the cavity formed over the crown of Downstream Surge Chamber, there was a strong need to determine the extents of cavity. Even to understand the influence of cavity formation on adjacent caverns, the cavity needs to be delineated. Therefore, the management of PHEP-II adopted several techniques to decipher the shape and dimensions of the cavity like, surveying, geophysical, cross-hole seismic surveys, borehole scanning, and exploratory drilling. The tentative shape of the cavity could finally be established. The findings from each method are explained in this paper.

scholarly journals Microgravity investigations of foundation conditions

Geophysics ◽  
1998 ◽  
Vol 63 (1) ◽  
pp. 95-103 ◽  
Author(s):  
Donald E. Yule ◽  
Michael K. Sharp ◽  
Dwain K. Butler
Keyword(s):  
Gravity Anomaly ◽  
Low Density ◽  
Positive Anomaly ◽  
Cavity Formation ◽  
Residual Gravity ◽  
Residual Gravity Anomaly ◽  
Exploratory Drilling ◽  
The Stability ◽  
Subsurface Cavities

A microgravity investigation was conducted in the upstream and downstream switchyards of the Wilson Dam powerplant, Florence, Alabama. The objective of the survey was the detection in the switchyard foundations of subsurface cavities or other anomalous conditions that could threaten the stability of the switchyard structures. The survey consisted of 288 gravity stations in the downstream switchyard and 347 stations in the upstream switchyard. Significant anomalous areas in the switchyards were selected on the basis of residual gravity anomaly maps. These results were prioritized and used to guide an exploratory drilling program to investigate the cause of the anomalies. Highest‐priority boring location recommendations were in negative gravity anomaly areas, since negative anomalies could be caused by actual cavities or low‐density zones that might represent incipient cavity formation. Remaining boring locations were in positive anomaly areas for verification purposes. The results of the borings confirm the presence of cavities and soft zones indicative of cavity formation.

A TEM study of the effect of oxygen on nanocavity formation and precipitation in rapid - solidified Fe-16Ni-9Cr stainless steels

1994 ◽  
Vol 52 ◽  
pp. 700-701
Author(s):  
S. Wisutmethangoon ◽  
T. F. Kelly ◽  
J.E. Flinn
Keyword(s):  
Stainless Steels ◽  
High Mobility ◽  
Hot Extrusion ◽  
Extrusion Ratio ◽  
Gas Atomization ◽  
Cavity Formation ◽  
Nucleation Sites ◽  
Heat Treated ◽  
Different Types ◽  
Effect Of Oxygen

Vacancies are introduced into the crystal phase during quenching of rapid solidified materials. Cavity formation occurs because of the coalescence of the vacancies into a cluster. However, because of the high mobility of vacancies at high temperature, most of them will diffuse back into the liquid phase, and some will be lost to defects such as dislocations. Oxygen is known to stabilize cavities by decreasing the surface energy through a chemisorption process. These stabilized cavities, furthermore, act as effective nucleation sites for precipitates to form during aging. Four different types of powders with different oxygen contents were prepared by gas atomization processing. The atomized powders were then consolidated by hot extrusion at 900 °C with an extrusion ratio 10,5:1. After consolidation, specimens were heat treated at 1000 °C for 1 hr followed by water quenching. Finally, the specimens were aged at 600 °C for about 800 hrs. TEM samples were prepared from the gripends of tensile specimens of both unaged and aged alloys.

“Cavity” formation in superplastically deformed aluminium alloys

1990 ◽  
Vol 48 (4) ◽  
pp. 958-959
Author(s):  
A. Cziráki ◽  
E. Ková-csetényi ◽  
T. Torma ◽  
T. Turmezey
Keyword(s):  
Grain Boundaries ◽  
Aluminium Alloys ◽  
Superplastic Deformation ◽  
Volume Fraction ◽  
Superplastic Forming ◽  
Polished Surface ◽  
Cavity Formation ◽  
Stress Concentrations ◽  
Electron Microscopic ◽  
Commercial Aluminium

It is known that the formation of cavities during superplastic deformation can be correlated with the development of stress concentrations at irregularities along grain boundaries such as particles, ledges and triple points. In commercial aluminium alloys Al-Fe-Si particles or other coarse constituents may play an important role in cavity formation.Cavity formation during superplastic deformation was studied by optical metallography and transmission scanning electron microscopic investigations on Al-Mg-Si and Al-Mg-Mn alloys. The structure of particles was characterized by selected area diffraction and X-ray micro analysis. The volume fraction of “voids” was determined on mechanically polished surface.It was found by electron microscopy that strongly deformed regions are formed during superplastic forming at grain boundaries and around coarse particles.According to electron diffraction measurements these areas consist of small micro crystallized regions. See Fig.l.Comparing the volume fraction and morphology of cavities found by optical microscopy a good correlation was established between that of micro crystalline regions.

The Assessment of Fear of Flying: Elaboration and Validation of a Videotape as an Analogous Situation of a Flight1

1997 ◽  
Vol 13 (2) ◽  
pp. 118-130 ◽  
Author(s):  
Juan I. Capafóns ◽  
Carmen D. Sosa ◽  
Manuel Herrero ◽  
Conrado Viña
Keyword(s):  
Heart Rate ◽  
Discriminant Analysis ◽  
Post Treatment ◽  
Subjective Measure ◽  
Physiological Measures ◽  
Personal Safety ◽  
Metal Detector ◽  
Fear Of Flying ◽  
Situational Anxiety ◽  
Treatment Measures

The results are presented for the validation of a videotape as an analogous situation for a flight. The video includes the most significant elements of a flight by air: confirmation of the flight, packing, going to the airport, checking-in, going through the metal-detector, departure lounge, boarding the plane, demonstration of the personal safety drills, interiors and exteriors during the flight and landing. Two physiological measures are used for validation (heart rate and temperature) and a subjective measure (situational anxiety, SA). The results (both t-tests and the discriminant analysis) indicate that the videotape is able to discriminate between phobics and non-phobics of flying in the three variables considered. With respect to sensitivity in detecting change produced by various treatments in clients with phobia of flying, the results are also satisfactory. A greater differentiation is produced between the pre-post treatment measures, both in subjective and in the physiological measures.

West China Hospital Back Pain Treatment Measures

2010 ◽  
Author(s):  
Ernest Volinn ◽  
Bangxiang Yang ◽  
Jing He ◽  
Xiaoming Sheng ◽  
Jian Ying ◽  
...  
Keyword(s):  
Back Pain ◽  
Pain Treatment ◽  
West China Hospital ◽  
West China ◽  
Treatment Measures

Using 4D Seismic Surveys and History Matching to Estimate Critical and Maximum Gas Saturation

2014 ◽  
Author(s):  
Dennis Chinedu Obidegwu ◽  
Romain Louis Chassagne ◽  
Colin Macbeth
Keyword(s):  
History Matching ◽  
Seismic Surveys ◽  
Gas Saturation ◽  
4D Seismic

Analysis of the monitoring study of the antibiotic-resistance of the agents of purulent-inflammatory processes of soft tissue

2018 ◽  
Vol 22 (2) ◽  
pp. 285-288
Author(s):  
A.P. Prevar ◽  
A.V. Kryzshanovskaya ◽  
V.A. Radionov ◽  
V.M. Mrug
Keyword(s):  
Soft Tissues ◽  
High Sensitivity ◽  
Biochemical Properties ◽  
Antimicrobial Drugs ◽  
Strict Adherence ◽  
E Coli ◽  
Monitoring Study ◽  
Treatment Measures ◽  
Inflammatory Processes ◽  
Main Factor

The main factor in the treatment of suppurative and inflammatory processes is the timely optimization of treatment measures taking into account the nature of the microflora and its susceptibility to antimicrobial drugs. The purpose of the study is to monitor the spectrum of microorganisms – pathogens of purulent-inflammatory processes of soft tissues in surgical patients; study of the sensitivity of isolated strains to antibiotics. The material was collected in accordance with aseptic rules. The identification of a pure culture of bacteria was carried out according to morphological, culture, biochemical properties, and the presence of virulence enzymes. Sensitivity of bacteria to antibiotics was determined by the standard disks method (by Kirby-Bauer’s). 255 patients with purulent-inflammatory processes of soft tissues were examined for the period from 2014 to 2017. 229 strains of isolated bacteria were included to Escherichia coli, Citrobacer freundii, Enterobacter cloacae, E.aerogenes, Proteus vulgaris, Staphylococcus aureus, S.epidermidis, Streptococcus pyogenes, S.viridians, S.agalactiae, Pseudomonas aeruginosa. The main cause of purulent-inflammatory processes of soft tissues is Staphylococci (67,2%). Compared to previous studies, the number of P.aeruginosa isolated cultures increased (7.9%). In monoculture and in association with other microorganisms, E. coli (9.6% of cases), E.cloacae et aerogenes (3.9% of cases), P.vulgaris (3.9% of cases), C.freundi (2.5% of cases), S.agalactiae, S.pyogenes, S.viridans (3.5%). The number of associated sows reaches 12%. Clinical strains of microorganisms remain most sensitive to fluoroquinolones, cephalosporins, and also retains high sensitivity to gentamicin, lincomycin, rifampicin, which is important for empirical antibiotic therapy. To increase the effectiveness of antibacterial therapy, strict adherence to the mode of appointment of antibiotics, justification of indications, a combination of antibiotics of different spectrum of action, mandatory correction after determining the sensitivity of the pathogen.

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