Parameter determination in field and laboratory tests

2014 ◽  
pp. 165-246
Author(s):  
Edyta E. Malinowska ◽  
Marek Bajda

Abstract The preconsolidation stress is an important phenomenon that determines the value of stress history exerted in the past on the subsoil in the geotechnical engineering. Overconsolidation ratio (OCR) is one of the main criteria conditioning soil behaviour and its characteristics. Here thought, the yield stress ratio (YSR) is used to determine the value of preconsolidation stress resulting from mechanical overburden than can be changed by many post depositional processes like secondary and tertiary compressibility, cementation, aging, temperature change and others. The yield stress ratio (YSR) is defined as the relationship between vertical yield stress (σ’vy) to the effective vertical stress (σ’v0). The eemian gyttja was used as a foundation in the engineering construction. In practical geotechnical engineering, evaluation of stress history is usually based on the overconsolidation ratio (OCR). The yield stress ratio (YSR) was used in the laboratory as one of the basic parameters for the geotechnical design of the structure. To know the relation between geological background, history and mechanical behaviour in long-time process of the soil aims a knowledge that can help engineers who often have to predict soil behaviour based upon the soil geological history and a few geotechnical data. In order to evaluate the yield stress ratio of eemian gyttja it is necessary to restore this soft, organic soil as much as possible to the in situ conditions. The laboratory tests were used to determinate the vertical yield stress and then the yield stress ratio. The laboratory tests were made in the automatic oedometer and the in situ tests were carried out on the dilatometer test (DMT). The comparison between the determination the yield stress ratio of eemian gyttja from the laboratory and the overconsolidation ratio from in situ test has been done. The studies have shown that the values of the overconsolidation ratio determinate from the laboratory tests are a little higher than determinate from the in situ tests.


VASA ◽  
2001 ◽  
Vol 30 (Supplement 58) ◽  
pp. 21-27
Author(s):  
Luther

In diabetic foot disease, critical limb ischaemia (CLI) cannot be precisely described using established definitions. For clinical use, the Fontaine classification complemented with any objective verification of a reduced arterial circulation is sufficient for decision making. For scientific purposes, objective measurement criteria should be reported. Assessment of CLI should rely on the physical examination of the limb arteries, complemented by laboratory tests like the shape of the PVR curve at ankle or toe levels, and arteriography. The prognosis of CLI in diabetic foot disease depends on the success of arterial reconstruction. The best prognosis for the patients is with a preserved limb. Reconstructive surgery is the best choice for the majority of patients.


2012 ◽  
Vol 17 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Rosalind Potts ◽  
Robin Law ◽  
John F. Golding ◽  
David Groome

Retrieval-induced forgetting (RIF) refers to the finding that the retrieval of an item from memory impairs the retrieval of related items. The extent to which this impairment is found in laboratory tests varies between individuals, and recent studies have reported an association between individual differences in the strength of the RIF effect and other cognitive and clinical factors. The present study investigated the reliability of these individual differences in the RIF effect. A RIF task was administered to the same individuals on two occasions (sessions T1 and T2), one week apart. For Experiments 1 and 2 the final retrieval test at each session made use of a category-cue procedure, whereas Experiment 3 employed category-plus-letter cues, and Experiment 4 used a recognition test. In Experiment 2 the same test items that were studied, practiced, and tested at T1 were also studied, practiced, and tested at T2, but for the remaining three experiments two different item sets were used at T1 and T2. A significant RIF effect was found in all four experiments. A significant correlation was found between RIF scores at T1 and T2 in Experiment 2, but for the other three experiments the correlations between RIF scores at T1 and T2 failed to reach significance. This study therefore failed to find clear evidence for reliable individual differences in RIF performance, except where the same test materials were used for both test sessions. These findings have important implications for studies involving individual differences in RIF performance.


1974 ◽  
Vol 32 (02/03) ◽  
pp. 483-491
Author(s):  
E. A Loeliger ◽  
M. J Boekhout-Mussert ◽  
L. P van Halem-Visser ◽  
J. D. E Habbema ◽  
H de Jonge

SummaryThe present study concerned the reproducibility of the so-called prothrombin time as assessed with a series of more commonly used modifications of the Quick’s onestage assay procedure, i.e. the British comparative reagent, homemade human brain thromboplastin, Simplastin, Simplastin A, and Thrombotest. All five procedures were tested manually on pooled lyophilized normal and patients’ plasmas. In addition, Simplastin A and Thrombotest were investigated semiautomatically on individual freshly prepared patients’ plasmas. From the results obtained, the following conclusions may be drawn :The reproducibility of results obtained with manual reading on lyophilized plasmas is satisfactory for all five test procedures. For Simplastin, the reproducibility of values in the range of insufficient anticoagulation is relatively low due to the low discrimination power of the test procedure in the near-normal range (so-called low sensitivity of rabbit brain thromboplastins). The reproducibility of Thrombotest excels as a consequence of its particularly easily discerned coagulation endpoint.The reproducibility of Thrombotest, when tested on freshly prepared plasmas using Schnitger’s semiautomatic coagulometer (a fibrinometer-liJce apparatus), is no longer superior to that of Simplastin A.The constant of proportionality between the coagulation times formed with Simplastin A and Thrombotest was estimated at 0.64.Reconstituted Thrombotest is stable for 24 hours when stored at 4° C, whereas reconstituted Simplastin A is not.The Simplastin A method and Thrombotest seem to be equally sensitive to “activation” of blood coagulation upon storage.


1964 ◽  
Vol 11 (02) ◽  
pp. 506-512 ◽  
Author(s):  
V. A Lovric ◽  
J Margolis

SummaryAn adaptation of “kaolin clotting time” and prothrombin time for use on haemolysed capillary blood provided simple and sensitive screening tests suitable for use in infants and children. A survey of three year’s experience shows that these are reliable routine laboratory tests for detection of latent coagulation disorders.


1981 ◽  
Vol 46 (04) ◽  
pp. 752-756 ◽  
Author(s):  
L Zuckerman ◽  
E Cohen ◽  
J P Vagher ◽  
E Woodward ◽  
J A Caprini

SummaryThrombelastography, although proven as a useful research tool has not been evaluated for its clinical utility against common coagulation laboratory tests. In this study we compare the thrombelastographic measurements with six common tests (the hematocrit, platelet count, fibrinogen, prothrombin time, activated thromboplastin time and fibrin split products). For such comparisons, two samples of subjects were selected, 141 normal volunteers and 121 patients with cancer. The data was subjected to various statistical techniques such as correlation, ANOVA, canonical and discriminant analysis to measure the extent of the correlations between the two sets of variables and their relative strength to detect blood clotting abnormalities. The results indicate that, although there is a strong relationship between the thrombelastographic variables and these common laboratory tests, the thrombelastographic variables contain additional information on the hemostatic process.


Sign in / Sign up

Export Citation Format

Share Document