The creep of ice measured with the pressuremeter

1988 ◽  
Vol 25 (2) ◽  
pp. 250-261 ◽  
Author(s):  
B. H. Kjartanson ◽  
D. H. Shields ◽  
L. Domaschuk ◽  
C.-S. Man

The pressuremeter has the potential to measure the creep parameters of ice in situ, that is to say, in the field, in ice at its natural temperature and natural stress environment, and in ice that has not been disturbed by sampling and handling. To prove that the pressuremeter can in fact be used to measure creep properties, a series of pressuremeter tests were run in the laboratory in poly crystalline ice at −2°C. It was found that (1) the particular pressuremeter used maintained an ability to measure creep deformation accurately over a period of 7 weeks, (2) the test results agree for the most part with the findings of other investigators who have used uniaxial compression tests, and (3) the pressuremeter brings into question at least one of the more common assumptions regarding primary creep. Key words: ice, freshwater, creep, pressuremeter.

1988 ◽  
Vol 133 ◽  
Author(s):  
K. J. Hemker ◽  
W. D. Nix

ABSTRACTThis study was undertaken to characterize the intermediate temperature creep properties of Ni3Al. Itfocuses on the mechanisms controlling creep deformation and their relationship to the anomalous yielding behavior of this alloy. Constant stress creep tests were conducted for temperatures between 713–973 K, and the following observations were made. The creep curves exhibited two distinct regions. Primary creep was followed by inverse creep. Specimens cooled under constant stress strained an additional 20% during cooling. Temperature drop experiments indicate that Ni3Al is weakened by the addition of creep deformation.Glide on the primary octahedral plane appears to be exhausted during primary creep. Slip trace and TEM studies indicate that inverse creep is controlled by slip on the cube cross slip plane and a secondary octahedral plane. Primary octahedral slip is observed in the specimens that are cooled and deformed under constant stress.


2020 ◽  
pp. 71-74
Author(s):  
M.M. Melnyk ◽  
◽  
S.V. Nespradko ◽  
I.V. Goncharuk ◽  
M.V. Marchenko ◽  
...  

The objective: analyse the effectiveness of diagnosis and treatment for early cervical cancer. Materials and methods. Analysed 107 cases of women’s disease on CIN ІІІ, cancer in situ, they were on treatment in National cancer institute and Kyiv dictrict cancer dispensary from 2010 till 2015 years. Results. Diagnosed percent relapse CIN ІІІ, cancer in situ contain 4.57% uninvasive and invasive form – 0.94%. Conclusion. According diagnostic CIN ІІ and CIN ІІІ is recommended to do treatment conization and dynamic dispensary observation. Are making complex program of infection HPV16, 18. In appering of margins resection some elements of tumor after wider conization by forms of cancer in situ. Many of expansive burns in cervical glands, in making of reproductive function, going disease (nodel leiomyoma of corpus uteri etc). In perspective is accept the notion of looking after and screening research of considering infection HPV16, 18 on CIN І, CIN ІІ. Key words: cervical cancer, сancer in situ, CIN І–ІІІ, diagnostic, treatment, conization.


Metals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 880 ◽  
Author(s):  
Rongchuang Chen ◽  
Haifeng Xiao ◽  
Min Wang ◽  
Jianjun Li

In this work, hot compression experiments of 300M steel were performed at 900–1150 °C and 0.01–10 s−1. The relation of flow stress and microstructure evolution was analyzed. The intriguing finding was that at a lower strain rate (0.01 s−1), the flow stress curves were single-peaked, while at a higher strain rate (10 s−1), no peak occurred. Metallographic observation results revealed the phenomenon was because dynamic recrystallization was more complete at a lower strain rate. In situ compression tests were carried out to compare with the results by ex situ compression tests. Hot working maps representing the influences of strains, strain rates, and temperatures were established. It was found that the power dissipation coefficient was not only related to the recrystallized grain size but was also related to the volume fraction of recrystallized grains. The optimal hot working parameters were suggested. This work provides comprehensive understanding of the hot workability of 300M steel in thermal compression.


2021 ◽  
Vol 21 (2) ◽  
Author(s):  
A. Mujdeci ◽  
D. V. Bompa ◽  
A. Y. Elghazouli

AbstractThis paper describes an experimental investigation into confinement effects provided by circular tubular sections to rubberised concrete materials under combined loading. The tests include specimens with 0%, 30% and 60% rubber replacement of mineral aggregates by volume. After describing the experimental arrangements and specimen details, the results of bending and eccentric compression tests are presented, together with complementary axial compression tests on stub-column samples. Tests on hollow steel specimens are also included for comparison purposes. Particular focus is given to assessing the confinement effects in the infill concrete as well as their influence on the axial–bending cross-section strength interaction. The results show that whilst the capacity is reduced with the increase in the rubber replacement ratio, an enhanced confinement action is obtained for high rubber content concrete compared with conventional materials. Test measurements by means of digital image correlation techniques show that the confinement in axial compression and the neutral axis position under combined loading depend on the rubber content. Analytical procedures for determining the capacity of rubberised concrete infilled cross-sections are also considered based on the test results as well as those from a collated database and then compared with available recommendations. Rubber content-dependent modification factors are proposed to provide more realistic representations of the axial and flexural cross-section capacities. The test results and observations are used, in conjunction with a number of analytical assessments, to highlight the main parameters influencing the behaviour and to propose simplified expressions for determining the cross-section strength under combined compression and bending.


2001 ◽  
Vol 9 (10-11) ◽  
pp. 915-922 ◽  
Author(s):  
J. Beddoes ◽  
D.Y. Seo ◽  
W.R. Chen ◽  
L. Zhao

1990 ◽  
Vol 27 (1) ◽  
pp. 58-67 ◽  
Author(s):  
Mohammed G. Kabir ◽  
Alan J. Lutenegger

An investigation was conducted to demonstrate the applicability of cylindrical piezocone and flat piezoblade tests for providing reliable estimates of the coefficient of consolidation in clays. Coefficients of consolidation were calculated from piezocone dissipation tests for different degrees of consolidation using theoretical time factors to provide a comparison with laboratory oedometer tests. Three techniques were developed to calculate the coefficient of consolidation from piezoblade dissipation tests. Results from in situ pore pressure dissipation tests were compared with laboratory oedometer tests performed on undisturbed samples oriented in both the vertical and horizontal directions, to provide reference values of cv and ch. The results of investigations conducted at several clay sites are presented. Key words: in situ tests, piezocone, piezoblade, coefficient of consolidation, oedometer test, clays.


Author(s):  
Miss Payal W. Paratpure

Tracking of public bus location requires a GPS device to be installed, and lots of bus operators in developing countries don't have such an answer in situ to supply an accurate estimation of bus time of arrival (ETA). Without ETA information, it's very difficult for the overall public to plan their journey effectively. In this paper, implementation of an innovative IOT solution to trace the real time location of buses without requiring the deployment of a GPS device is discussed. It uses Bluetooth Low Energy (BLE) proximity beacon to trace the journey of a bus by deploying an Estimate location beacon on the bus. BLE detection devices (Raspberry Pi 4) are installed at selected bus stops along the path to detect the arrival of buses. Once detected, the situation of the bus is submitted to a cloud server to compute the bus ETAs. A field trial is currently being conducted in Johor, Malaysia together with an area bus operator on one single path. Our test results showed that the detection of BLE beacons is extremely accurate and it's feasible to trace the situation of buses without employing a GPS device during a cost-effective way.


2010 ◽  
Vol 134 (5) ◽  
pp. 744-750
Author(s):  
R. Marshall Austin ◽  
Agnieszka Onisko ◽  
Marek J. Druzdzel

Abstract Context.—Evaluation of cervical cancer screening has grown increasingly complex with the introduction of human papillomavirus (HPV) vaccination and newer screening technologies approved by the US Food and Drug Administration. Objective.—To create a unique Pittsburgh Cervical Cancer Screening Model (PCCSM) that quantifies risk for histopathologic cervical precancer (cervical intraepithelial neoplasia [CIN] 2, CIN3, and adenocarcinoma in situ) and cervical cancer in an environment predominantly using newer screening technologies. Design.—The PCCSM is a dynamic Bayesian network consisting of 19 variables available in the laboratory information system, including patient history data (most recent HPV vaccination data), Papanicolaou test results, high-risk HPV results, procedure data, and histopathologic results. The model's graphic structure was based on the published literature. Results from 375 441 patient records from 2005 through 2008 were used to build and train the model. Additional data from 45 930 patients were used to test the model. Results.—The PCCSM compares risk quantitatively over time for histopathologically verifiable CIN2, CIN3, adenocarcinoma in situ, and cervical cancer in screened patients for each current cytology result category and for each HPV result. For each current cytology result, HPV test results affect risk; however, the degree of cytologic abnormality remains the largest positive predictor of risk. Prior history also alters the CIN2, CIN3, adenocarcinoma in situ, and cervical cancer risk for patients with common current cytology and HPV test results. The PCCSM can also generate negative risk projections, estimating the likelihood of the absence of histopathologic CIN2, CIN3, adenocarcinoma in situ, and cervical cancer in screened patients. Conclusions.—The PCCSM is a dynamic Bayesian network that computes quantitative cervical disease risk estimates for patients undergoing cervical screening. Continuously updatable with current system data, the PCCSM provides a new tool to monitor cervical disease risk in the evolving postvaccination era.


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