Effect of overburden pressure on liquefaction resistance of sand

1994 ◽  
Vol 31 (1) ◽  
pp. 53-60 ◽  
Author(s):  
V.S. Pillai ◽  
P.M. Byrne
Keyword(s):  
Published Data ◽  
Confining Stress ◽  
Liquefaction Resistance ◽  
Overburden Pressure ◽  
Site Specific ◽  
Indirect Approach ◽  
Cyclic Resistance ◽  
Wide Range ◽  
Cyclic Resistance Ratio ◽  
A Site

The effect of overburden pressure on liquefaction resistance of sand is studied and results of a site-specific investigation are presented. When estimating liquefaction resistance of sand from the indirect approach using the chart suggested by Seed et al. (1984) a correction factor Kσ is applied to account for vertical effective overburden stresses larger than 1 tsf. Published data indicate a decrease in Kσ with increased confining stress but with a wide range of Kσ values for the same confining stresses, predicting significantly differing liquefaction resistance. The effect of confining stresses on liquefaction resistance was investigated as part of a comprehensive seismic assessment of Duncan Dam in British Columbia. The results indicate that Kσ is dependent on confining stresses and the relative density of the soil, and values are generally significantly higher than much of the previously published data. Key words : liquefaction, sand, confining stress, density, cyclic resistance ratio.

Confining stress and static shear effects in cyclic liquefaction

2001 ◽  
Vol 38 (3) ◽  
pp. 580-591 ◽  
Author(s):  
Y P Vaid ◽  
J D Stedman ◽  
S Sivathayalan
Keyword(s):  
Initial Density ◽  
Confining Pressure ◽  
Empirical Method ◽  
Shear Stresses ◽  
Confining Stress ◽  
Liquefaction Resistance ◽  
Sand Liquefaction ◽  
Cyclic Resistance ◽  
Cyclic Resistance Ratio ◽  
Static Shear

Liquefaction resistance of a sand under cyclic loading is assessed and the effects of the levels of confining pressure and static shear on resistance to liquefaction are investigated. Site-specific values of the resistance under specified levels of confining and static shear stresses are measured in the laboratory. The measured values are compared with those which would be predicted by the application of empirical multiplying factors Kσ and Kα to the reference resistance at 100 kPa effective confining stress with no static shear. It is shown that Kσ and Kα are not independent, as assumed in current practice. The combined factor Kσ × Kα resulting from the empirical method is shown to underestimate the cyclic resistance ratio regardless of the initial density and confining and static shear levels. The degree of conservatism is most dramatic at looser density states.Key words: sand, liquefaction, static, cyclic, static shear, confining stress.

scholarly journals Ferritin Conjugates With Multiple Clickable Amino Acids Encoded by C-Terminal Engineered Pyrrolysyl-tRNA Synthetase

2021 ◽  
Vol 9 ◽  
Author(s):  
Yi-Hui Wang ◽  
Mu-Lung Jian ◽  
Pei-Jung Chen ◽  
Jo-Chu Tsou ◽  
Le P. Truong ◽  
...  
Keyword(s):  
Click Reaction ◽  
Trna Synthetase ◽  
Delivery Systems ◽  
Her2 Receptor ◽  
Site Specific ◽  
Protein Cage ◽  
Specific Loading ◽  
Wide Range ◽  
Multiple Drugs ◽  
A Site

This study reports the application of expanding genetic codes in developing protein cage-based delivery systems. The evolved Methanosarcina mazei pyrrolysyl-tRNA synthetase (PylRS)•tRNAPyl pairs derived from directed evolution are examined to probe their recognition for para-substituted phenylalanine analogs. The evolved MmPylRS, AzFRS, harboring a wide range of substrates, is further engineered at the C-terminal region into another variant, AzFRS-MS. AzFRS-MS shows suppression of the elevated sfGFP protein amount up to 10 TAG stop codons when charging p-azido-l-phenylalanine (AzF, 4), which allows the occurrence of click chemistry. Since protein nanocages used as drug delivery systems that encompass multiple drugs through a site-specific loading approach remain largely unexplored, as a proof of concept, the application of AzFRS-MS for the site-specific incorporation of AzF on human heavy chain ferritin (Ftn) is developed. The Ftn-4 conjugate is shown to be able to load multiple fluorescence dyes or a therapeutic agent, doxorubicin (Dox), through the strain-promoted azide-alkyne cycloaddition (SPAAC) click reaction. Aiming to selectively target Her2+ breast cancer cells, Ftn-4-DOX conjugates fused with a HER2 receptor recognition peptide, anti-Her2/neu peptide (AHNP), is developed and demonstrated to be able to deliver Dox into the cell and to prolong the drug release. This work presents another application of evolved MmPylRS systems, whose potential in developing a variety of protein conjugates is noteworthy.

A laboratory investigation of the dynamic properties of tailings

2011 ◽  
Vol 48 (11) ◽  
pp. 1587-1600 ◽  
Author(s):  
Michael James ◽  
Michel Aubertin ◽  
Dharma Wijewickreme ◽  
G. Ward Wilson
Keyword(s):  
Dynamic Properties ◽  
Cyclic Stress ◽  
Test Results ◽  
Liquefaction Resistance ◽  
Cyclic Stress Ratio ◽  
Cyclic Resistance ◽  
Direct Simple Shear ◽  
Cyclic Resistance Ratio ◽  
Modulus Reduction

The dynamic response of tailings from a gold mine located in western Quebec was evaluated using cyclic laboratory testing. These tailings are classified as nonplastic silt and sand. Specimens of the tailings were prepared as slurries, consolidated to vertical effective stresses of 100–400 kPa, and subjected to cyclic direct simple shear testing with cyclic stress ratio, CSR, values between 0.075 and 0.15. The shear modulus reduction of the tailings under cyclic loading was found to be fairly similar to that described for clean sands in the literature. The cyclic resistance ratio, CRR (which reflects the liquefaction resistance), of the samples was not significantly affected by the effective consolidation stress (in the range considered here). Analysis of test results with the simplified method of liquefaction evaluation indicates that this method may be applicable to these tailings. However, other factors, such as the possible effects of layering and ageing of the tailings in situ, should also be considered in such an assessment.

scholarly journals Liquefaction Characteristics of Sands Based on Cyclic Direct Simple Shear Test

2020 ◽  
Vol 20 (4) ◽  
pp. 239-249
Author(s):  
Byongyoun Hwang ◽  
Tae-Young Kwak ◽  
Jongkwan Kim ◽  
Jin-Tae Han
Keyword(s):  
Simple Shear ◽  
Evaluation Method ◽  
Resistance Ratio ◽  
Test Results ◽  
Liquefaction Resistance ◽  
Ottawa Sand ◽  
Cyclic Resistance ◽  
Direct Simple Shear ◽  
Cyclic Resistance Ratio ◽  
Particle Shapes

In this study, a series of cyclic direct simple shear tests were conducted on Pohang sand, Jumunjin sand, and Ottawa sand. The cyclic resistance ratio (CRR) was derived on the basis of the test results obtained. For verification of the effect of particle distribution on liquefaction resistance, the simplified method for evaluation of the possibility of liquefaction was used to assess these sands. The test results showed that the cyclic resistance ratio of Pohang sand was the lowest, which was consistent with the result of the simplified evaluation method for determining the possibility of liquefaction. In addition, the results showed that the liquefaction resistance increased for particle shapes being more angular than round. Normalization was subsequently applied to minimize the effects of the different factors, and the correlation between the CRR<sub>N=10</sub> normalization curve and the CRR<sub>N=15</sub> normalization curve was confirmed.

scholarly journals Site-specific analysis of N-glycans from different sheep prion strains

2021 ◽  
Vol 17 (2) ◽  
pp. e1009232
Author(s):  
Natali Nakić ◽  
Thanh Hoa Tran ◽  
Mislav Novokmet ◽  
Olivier Andreoletti ◽  
Gordan Lauc ◽  
...  
Keyword(s):  
Prion Protein ◽  
Prion Diseases ◽  
Mammalian Species ◽  
Site Specific ◽  
Prion Strains ◽  
Glycosylation Sites ◽  
Specific Analysis ◽  
Wide Range ◽  
The One ◽  
A Site

Prion diseases are a group of neurodegenerative diseases affecting a wide range of mammalian species, including humans. During the course of the disease, the abnormally folded scrapie prion protein (PrPSc) accumulates in the central nervous system where it causes neurodegeneration. In prion disorders, the diverse spectrum of illnesses exists because of the presence of different isoforms of PrPSc where they occupy distinct conformational states called strains. Strains are biochemically distinguished by a characteristic three-band immunoblot pattern, defined by differences in the occupancy of two glycosylation sites on the prion protein (PrP). Characterization of the exact N-glycan structures attached on either PrPC or PrPSc is lacking. Here we report the characterization and comparison of N-glycans from two different sheep prion strains. PrPSc from both strains was isolated from brain tissue and enzymatically digested with trypsin. By using liquid chromatography coupled to electrospray mass spectrometry, a site-specific analysis was performed. A total of 100 structures were detected on both glycosylation sites. The N-glycan profile was shown to be similar to the one on mouse PrP, however, with additional 40 structures reported. The results presented here show no major differences in glycan composition, suggesting that glycans may not be responsible for the differences in the two analyzed prion strains.

scholarly journals Polyspecific monoclonal lupus autoantibodies reactive with both polynucleotides and phospholipids.

1981 ◽  
Vol 153 (4) ◽  
pp. 897-909 ◽  
Author(s):  
E M Lafer ◽  
J Rauch ◽  
C Andrzejewski ◽  
D Mudd ◽  
B Furie ◽  
...  
Keyword(s):  
Test System ◽  
Activated Partial Thromboplastin Time ◽  
Biological Molecules ◽  
Spleen Cells ◽  
Phosphatidyl Glycerol ◽  
Site Specific ◽  
Wide Range ◽  
A Site ◽  
Idiotypic Antibody ◽  
Phosphate Groups

Hybridomas the produce anti-DNA autoantibodies were prepared from spleen cells of unimmunized MRL/1 mice, a strain that spontaneously develops severe systemic lupus erythematous (SLE). Reactivities of these monoclonal antibodies with a wide range of polynucleotides prompted tests of their reactions with phospholipids which, like polynucleotides, contain diester-linked phosphate groups in their backbones. In competitive radioimmunoassays, cardiolipin, phosphatidic acid, and phosphatidyl glycerol blocked the binding of these hybridoma antibodies to denatured DNA. These phospholipids also specifically inhibited the reaction between a hybridoma antibody and a site-specific anti-idiotypic antibody. The antinuclear reaction of one of these antibodies was specifically inhibited by cardiolipin. This same antibody prolonged the activated partial thromboplastin time in a manner characteristic of a lupus anticoagulant, presumably by binding to phospholipid in the test system. The polyspecific reactivity of a single molecular species of lupus autoantibody suggests that some of the diverse serological abnormalities of SLE may be a result of the binding of certain autoantibodies to a phosphodiester-containing epitope that is present in diverse biological molecules.

It is better an approximate answer to the right question than the exact answer to the wrong question : the case of the psychometric analysis of the ASQ:SE

2020 ◽  
Author(s):  
Luis Anunciacao ◽  
janet squires ◽  
J. Landeira-Fernandez
Keyword(s):  
Internal Structure ◽  
Statistical Methods ◽  
Principal Component ◽  
Psychological Theory ◽  
Published Data ◽  
Multivariate Statistical ◽  
Exact Answer ◽  
Wide Range ◽  
Ages And Stages Questionnaire ◽  
The Right

One of the main activities in psychometrics is to analyze the internal structure of a test. Multivariate statistical methods, including Exploratory Factor analysis (EFA) and Principal Component Analysis (PCA) are frequently used to do this, but the growth of Network Analysis (NA) places this method as a promising candidate. The results obtained by these methods are of valuable interest, as they not only produce evidence to explore if the test is measuring its intended construct, but also to deal with the substantive theory that motivated the test development. However, these different statistical methods come up with different answers, providing the basis for different analytical and theoretical strategies when one needs to choose a solution. In this study, we took advantage of a large volume of published data (n = 22,331) obtained by the Ages and Stages Questionnaire Social-Emotional (ASQ:SE), and formed a subset of 500 children to present and discuss alternative psychometric solutions to its internal structure, and also to its subjacent theory. The analyses were based on a polychoric matrix, the number of factors to retain followed several well-known rules of thumb, and a wide range of exploratory methods was fitted to the data, including EFA, PCA, and NA. The statistical outcomes were divergent, varying from 1 to 6 domains, allowing a flexible interpretation of the results. We argue that the use of statistical methods in the absence of a well-grounded psychological theory has limited applications, despite its appeal. All data and codes are available at https://osf.io/z6gwv/.

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