Runout of dry granular avalanches

1999 ◽  
Vol 36 (2) ◽  
pp. 313-320 ◽  
Author(s):  
T R Davies ◽  
M J McSaveney
Keyword(s):  
Large Volume ◽  
Laboratory Tests ◽  
Laboratory Experiments ◽  
Laboratory Data ◽  
Rock Avalanche ◽  
Consistent Pattern ◽  
Runout Distance ◽  
Grain Flow ◽  
Flow Mechanisms ◽  
Fall Height

Laboratory experiments on granular avalanching of dry sands and gravels reveal a consistent pattern of runout distance varying with fall height, fall slope, and volume of material for volumes ranging from 0.1 to 1000 L. Data from the South Ashburton rock avalanche deposit show that its runout behaviour differs only slightly from that of the laboratory avalanches, extending the range of this behaviour to granular avalanches with volumes of about 100 000 m3. By contrast, data from much larger rock avalanches (> 107 m3) depart significantly from the trends of the laboratory data; some factor not present in the laboratory, such as rock fragmentation or the presence of an erodible substrate, must influence the behaviour of these larger events. Travel angles as low as 13° in the laboratory tests result from grain flow mechanisms with normal friction coefficients; they are not associated only with large-volume events and do not necessarily indicate unusual material mobility at any scale.

scholarly journals 3-D models and structural analysis of analogue rock avalanche deposits: a kinematic analysis of the propagation mechanism

2015 ◽  
Vol 3 (4) ◽  
pp. 1255-1288 ◽  
Author(s):  
C. Longchamp ◽  
A. Abellan ◽  
M. Jaboyedoff ◽  
I. Manzella
Keyword(s):  
Structural Analysis ◽  
Laboratory Experiments ◽  
Median Filter ◽  
Laboratory Data ◽  
Rock Avalanche ◽  
Structural Features ◽  
Laboratory Simulation ◽  
Propagation Mechanism ◽  
Accurate Analysis ◽  
Rock Avalanches

Abstract. Rock avalanches are extremely destructive and uncontrollable events that involve a great volume of material (> 106 m3), several complex processes and they are difficult to witness. For this reason the study of these phenomena using analogue modelling and the accurate analysis of deposit structures and features of laboratory data and historic events become of great importance in the understanding of their behavior. The main objective of this research is to analyze rock avalanche dynamics by means of a detailed structural analysis of the deposits coming from data of 3-D measurements of mass movements of different magnitudes, from decimeter level scale laboratory experiments to well-studied rock avalanches of several square kilometers magnitude. Laboratory experiments were performed on a tilting plane on which a certain amount of a well-defined granular material is released, propagates and finally stops on a horizontal surface. The 3-D geometrical model of the deposit is then obtained using either a scan made with a 3-D digitizer (Konica Minolta vivid 9i) either using a photogrammetric method called Structure-from-Motion (SfM) which requires taking several pictures from different point of view of the object to be modeled. In order to emphasize and better detect the fault structures present in the deposits, we applied a median filter with different moving windows sizes (from 3 × 3 to 9 × 9 nearest neighbors) to the 3-D datasets and a gradient operator along the direction of propagation. The application of these filters on the datasets results in: (1) a precise mapping of the longitudinal and transversal displacement features observed at the surface of the deposits; and (2) a more accurate interpretation of the relative movements along the deposit (i.e. normal, strike-slip, inverse faults) by using cross-sections. Results shows how the use of filtering techniques reveal disguised features in the original point cloud and that similar displacement patterns are observable both in the laboratory simulation and in the real scale avalanche, regardless the size of the avalanche. Furthermore, we observed how different structural features including transversal fractures and folding patterns tend to show a constant wavelength proportional to the size of the avalanche event.

scholarly journals Prediction of Hospital Mortality Rates by Admission Laboratory Tests

2006 ◽  
Vol 52 (2) ◽  
pp. 325-328 ◽  
Author(s):  
Paul Froom ◽  
Zvi Shimoni
Keyword(s):  
Internal Medicine ◽  
Logistic Regression ◽  
Confidence Interval ◽  
Regression Model ◽  
Odds Ratio ◽  
Laboratory Tests ◽  
Logistic Regression Model ◽  
Complete Blood Count ◽  
Laboratory Data ◽  
Regional Hospital

Abstract Background: The aim of this study was to explore whether electronically retrieved laboratory data can predict mortality in internal medicine departments in a regional hospital. Methods: All 10 308 patients hospitalized in internal medicine departments over a 1-year period were included in the cohort. Nearly all patients had a complete blood count and basic clinical chemistries on admission. We used logistic regression analysis to predict the 573 deaths (5.6%), including all variables that added significantly to the model. Results: Eight laboratory variables and age significantly and independently contributed to a logistic regression model (area under the ROC curve, 88.7%). The odds ratio for the final model per quartile of risk was 6.44 (95% confidence interval, 5.42–7.64), whereas for age alone, the odds ratio per quartile was 2.01 (95% confidence interval, 1.84–2.19). Conclusions: A logistic regression model including only age and electronically retrieved laboratory data highly predicted mortality in internal medicine departments in a regional hospital, suggesting that age and routine admission laboratory tests might be used to ensure a fair comparison when using mortality monitoring for hospital quality control.

scholarly journals Automated mapping of laboratory tests to LOINC codes using noisy labels in a national electronic health record system database

2018 ◽  
Vol 25 (10) ◽  
pp. 1292-1300 ◽  
Author(s):  
Sharidan K Parr ◽  
Matthew S Shotwell ◽  
Alvin D Jeffery ◽  
Thomas A Lasko ◽  
Michael E Matheny
Keyword(s):  
Machine Learning ◽  
Laboratory Tests ◽  
Laboratory Data ◽  
Unlabeled Data ◽  
Department Of Veterans Affairs ◽  
Test Frequency ◽  
Record System ◽  
Automated Mapping ◽  
Meaningful Context ◽  
Noisy Labels

Abstract Objective Standards such as the Logical Observation Identifiers Names and Codes (LOINC®) are critical for interoperability and integrating data into common data models, but are inconsistently used. Without consistent mapping to standards, clinical data cannot be harmonized, shared, or interpreted in a meaningful context. We sought to develop an automated machine learning pipeline that leverages noisy labels to map laboratory data to LOINC codes. Materials and Methods Across 130 sites in the Department of Veterans Affairs Corporate Data Warehouse, we selected the 150 most commonly used laboratory tests with numeric results per site from 2000 through 2016. Using source data text and numeric fields, we developed a machine learning model and manually validated random samples from both labeled and unlabeled datasets. Results The raw laboratory data consisted of >6.5 billion test results, with 2215 distinct LOINC codes. The model predicted the correct LOINC code in 85% of the unlabeled data and 96% of the labeled data by test frequency. In the subset of labeled data where the original and model-predicted LOINC codes disagreed, the model-predicted LOINC code was correct in 83% of the data by test frequency. Conclusion Using a completely automated process, we are able to assign LOINC codes to unlabeled data with high accuracy. When the model-predicted LOINC code differed from the original LOINC code, the model prediction was correct in the vast majority of cases. This scalable, automated algorithm may improve data quality and interoperability, while substantially reducing the manual effort currently needed to accurately map laboratory data.

scholarly journals Polyarthritis associated with COVID-19 (clinical case)

2021 ◽  
Vol 15 (5) ◽  
pp. 76-79
Author(s):  
E. S. Aronova ◽  
B. S. Belov
Keyword(s):  
Clinical Data ◽  
Laboratory Tests ◽  
Clinical Case ◽  
Clinical Observation ◽  
Laboratory Data ◽  
Careful Study ◽  
Instrumental Methods

The article describes the clinical observation of the onset of polyarthritis after COVID-19. Clinical data, laboratory tests' and instrumental methods results in dynamics, as well as approaches to therapy are presented. The discussion reflects modern views on the causes of the development of articular syndrome after SARS-CoV-2, with special attention to the need for a careful study of the history, clinical and laboratory data of patients with COVID-19.

Analysis of the World's First Polymer Injectivity Test in a Carbonate Reservoir Under Extreme Harsh Conditions in ADNOC's Reservoirs

2021 ◽  
Author(s):  
Juan Manuel Leon ◽  
Shehadeh K. Masalmeh ◽  
Siqing Xu ◽  
Ali M. AlSumaiti ◽  
Ahmed A. BinAmro ◽  
...  
Keyword(s):  
High Temperature ◽  
Laboratory Experiments ◽  
High Salinity ◽  
Laboratory Data ◽  
Injection Pressure ◽  
Carbonate Reservoir ◽  
Experimental Program ◽  
Full Field ◽  
Harsh Conditions

Abstract Assessing polymer injectivity for EOR field applications is highly important and challenging. An excessive injectivity reduction during and after polymer injection may potentially affect the well integrity and recovery efficiency and consequently, injection strategy and the economics of the polymer projects. Moreover, well conditions such as skin, completion configuration, and injection water quality can significantly impact polymer injectivity. Additionally, the presence of fractures or micro-fractures may govern injection pressure. In contrast, historic field applications have shown that polymer injectivity is in general better than expected from simulations or laboratory data. In the laboratory experiments, the polymer injectivity has been evaluated by injection of significant amounts of pore volumes of polymer at relevant well-injection rates. In addition, several experiments were performed to measure the complex in-situ rheology expected to dominate the flow near the wellbore This paper presents the analysis of the the world's first polymer injectivity test (PIT) conducted in a high temperature and high salinity (HTHS) carbonate reservoir in Abu Dhabi as part of a comprehensive de-risking program for a new polymer-based EOR scheme proposed by ADNOC for these challenging carbonate reservoirs (see Masalmeh et. al., 2014). The de-risking program includes an extensive laboratory experimental program and field injectivity test to ensure that the identified polymer can be injected and propagated in the target formation before multi-well pilot and full-field implementation stages. Experimental laboratory data and the field injectivity test results are presented in earlier publications (Masalmeh et. al., 2019; Rachapudi et. al., 2020) and references therein. This PIT is the world's first polymer injectivity test in a carbonate reservoir under such harsh conditions of high salinity, high content of divalent ions and high temperature. In addition, the polymer used during the test has never been field-tested before. Therefore, the results of the PIT interpretation will help to de-risk the suitable polymer for the future inter-well pilot for the new proposed EOR Polymer-based scheme and it is a game-changer to unlock several opportunities for different Chemical EOR applications on full-field scale in other reservoirs with similar characteristics. A single well radial simulation model was built to integrate the surveillance data during PIT and the extensive laboratory experiments. Morever, multiple Pressure Fall Off Tests (PFOs) during the same periods were analyzed and intergaretd in the model.The study assessed the effect of polymer viscosity on mobility reduction, evaluated the polymer bank propagation, investigated the effect of the skin build-up, residual resistance factor (RRF) and shear effects on the well injectivity. Additionally, a comprehensive assisted history match method and robust simulation sensitivity analysis was implemented, thousands of sensitivity simulation runs were performed to capture several possible injection scenarios and validate laboratory parameters. The simulation study confirmed that the PIT could be interpreted using the laboratory-measured polymer parameters such as polymer bulk viscosity, in-situ rheology, RRF and adsorption.

scholarly journals Effects of ACEI and ARB on COVID-19 patients: A meta-analysis

2020 ◽  
Vol 21 (4) ◽  
pp. 147032032098132
Author(s):  
Yang Xue ◽  
Shaoqing Sun ◽  
Jianing Cai ◽  
Linwen Zeng ◽  
Shihui Wang ◽  
...  
Keyword(s):  
Laboratory Tests ◽  
Enzyme Inhibitors ◽  
Angiotensin Receptor Blockers ◽  
Meta Analysis ◽  
Laboratory Data ◽  
Angiotensin Converting Enzyme Inhibitors ◽  
Converting Enzyme Inhibitors ◽  
Receptor Blockers ◽  
Group D ◽  
D Dimer

Background: The clinical use of angiotensin-converting enzyme inhibitors (ACEI) and angiotensin-receptor blockers (ARB) in patients with COVID-19 infection remains controversial. Therefore, we performed a meta-analysis on the effects of ACEI/ARB on disease symptoms and laboratory tests in hypertensive patients infected with COVID-19 virus and those who did not use ACEI/ARB. Methods: We systematically searched the relevant literatures from Pubmed, Embase, EuropePMC, CNKI, and other databases during the study period of 31 December 2019 (solstice, 15 March 2020), and analyzed the differences in symptoms and laboratory tests between patients with COVID-19 and hypertension who used ACEI/ARB drugs and those who did not. All statistical analyses were performed with REVMAN5.3. Results: We included a total of 1808 patients with hypertension diagnosed with COVID-19 in six studies. Analysis results show that ACEI/ARB drugs group D-dimer is lower (SMD = −0.22, 95%CI: −0.36 to −0.06), and the chances of getting fever is lower (OR = 0.74, 95%CI: 0.55 to 0.98). Meanwhile, laboratory data and symptoms were not statistical difference, but creatinine tends to rise (SMD = 0.22, 95% CI: 0.04 to 0.41). Conclusion: We found that the administration of ACEI/ARB drugs had positive effect on reducing D-dimer and the number of people with fever. Meanwhile it had no significant effect on other laboratory tests (creatinine excepted) or symptoms in patients with COVID-19, while special attention was still needed in patients with renal insufficiency.

Effect of Spatial Variation of a Wave Field on the Resulting Ripple Characteristics and Comparison to Present Ripple Predictors

2009 ◽  
Author(s):  
Blake J. Landry ◽  
Yovanni A. Catan˜o-Lopera ◽  
Matthew J. Hancock ◽  
Chiang C. Mei ◽  
Marcelo H. Garci´a
Keyword(s):  
Spatial Variation ◽  
Wave Field ◽  
Test Section ◽  
Laboratory Experiments ◽  
Laboratory Data ◽  
Standing Waves ◽  
Sand Ripple ◽  
Wave Measurements ◽  
Progressive Waves ◽  
Sediment Test

Laboratory experiments analyzed herein focus on the validity of ripple predictors under spatially variable wave envelopes. Present-day ripple predictors commonly derived from laboratory data (for smaller wave periods of about 1 to 4 s) within which only small regions of the facilities were used to observe and measure the sand ripple geometric characteristics of the nearly progressive waves measured overhead. When extended to large sediment test sections, our results show that the predictors are still valid along the tank under wave conditions which have significant wave envelope spatial variation (e.g., standing waves), provided that ripple predictors use the wave measurements directly above the respective locations within the computations. Results indicate that even under the case of mild reflection, noticeable variation in ripple characteristics can be seen along the sediment test section; thus, compels the necessity of measuring the wave field along the entire sediment section to achieve accurate results.

scholarly journals Seismic surveying and imaging at the laboratory scale: A framework to cross-validate experiments and simulations for a salt-body environment

Geophysics ◽  
2020 ◽  
Vol 85 (3) ◽  
pp. T123-T139
Author(s):  
Bence Solymosi ◽  
Nathalie Favretto-Cristini ◽  
Vadim Monteiller ◽  
Paul Cristini ◽  
Bjørn Ursin ◽  
...  
Keyword(s):  
Experimental Data ◽  
Laboratory Experiments ◽  
Field Experiments ◽  
Imaging Techniques ◽  
Laboratory Data ◽  
Seismic Exploration ◽  
Scale Model ◽  
Water Tank ◽  
Time Migration ◽  
Reduced Scale

Laboratory experiments have been recently reintroduced into the ideas-to-applications pipeline for geophysical applications. Benefiting from recent technological advances, we believe that in the coming years, laboratory experiments can play a major role in supporting field experiments and numerical modeling, to explore some of the current challenges of seismic imaging in terms of, for instance, acquisition design or benchmarking of new imaging techniques at a low cost and in an agile way. But having confidence in the quality and accuracy of the experimental data obtained in a complex configuration, which mimics at a reduced scale a real geologic environment, is an essential prerequisite. This requires a robust framework regardless of the configuration studied. Our goal is to provide a global overview of this framework in the context of offshore seismics. To illustrate it, a reduced-scale model is used to represent a 3D complex-shaped salt body buried in sedimentary layers with curved surfaces. Zero-offset and offset reflection data are collected in a water tank, using a conventional pulse-echo technique. Then, a cross-validation approach is applied, which allows us, through comparison between experimental data and the numerical simulation, to point out some necessary future improvements of the laboratory setup to increase the accuracy of the experimental data, and the limitations of the numerical implementation that must also be tackled. Due to this approach, a hierarchical list of points can be collected, to which particular attention should be paid to make laboratory experiments an efficient tool in seismic exploration. Finally, the quality of the complex reduced-scale model and the global framework is successfully validated by applying reverse time migration to the laboratory data.

Kaolin Particle Film Prevents Galling by Gynaikothrips uzeli

2009 ◽  
Vol 10 (1) ◽  
pp. 21 ◽  
Author(s):  
David W. Held ◽  
Corey Wheeler ◽  
David W. Boyd
Keyword(s):  
Laboratory Tests ◽  
Laboratory Experiments ◽  
Ornamental Plant ◽  
Effective Alternative ◽  
Ficus Benjamina ◽  
Choice Tests

Feeding by Gynaikothrips uzeli Zimmerman (Thysanoptera: Phlaeothripidae), a pest thrips, induces galls on the ornamental plant Ficus benjamina, which disfigures plants and can facilitate incidental transport of pests. This study evaluated foliar applications of azadirachtin (Azatin XL), bifenthrin (Talstar), or kaolin (Surround WP) to prevent galling in field and laboratory experiments. Azadirachtin did not significantly prevent galling, but kaolin-treated cuttings had 80% reduction in number of galls in laboratory tests, and in the field, kaolintreated plants had ≥ 74% reduction in number of galls versus unprotected plants. Weekly applications of kaolin provided comparable protection to bifenthrin. Laboratory choice and no-choice tests indicate kaolin is not lethal and adult G. uzeli do not avoid kaolin-treated surfaces. Particle film products are an effective alternative to insecticides for preventing leaf galls on weeping fig. Accepted for publication 18 February 2009. Published 7 April 2009.

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