Conventional Static Tests Research Articles

Are Learning Tests the Better Version of Intelligence Tests?

Under the rubrics Learning Potential Assessment, Learning Test Concept, Testing the Limits, and Interactive or Dynamic Assessment, alternatives or supplements to the conventional static intelligence test are discussed and subjected to empirical scrutiny. Researchers hope that prompts built into the test will make it possible to determine the “zone of proximal development” (Vygotsky) and lead to a fairer and more valid assessment. The authors begin by reviewing conventional attempts at validation using external criteria such as school grades and teacher ratings. This is followed by a review of more recent research done in the construct validation tradition. In the latter, learning tests vs. conventional intelligence tests are compared with basic components of intelligence (measured by using elementary cognitive tasks) and knowledge acquisition processes (in complex problem solving scenarios). Although in these attempts at validation the learning tests turn out to be superior to the static versions, much more research needs to be done in order to answer the question that headlines this article.

Monoethylglycinexylidide as an early predictor of posttraumatic multiple organ failure.

The prognostic value of a dynamic liver-function test, based on the hepatic conversion of lidocaine to monoethylglycinexylidide (MEGX), in predicting multiple organ failure (MOF) was prospectively investigated in 28 critically ill patients after multiple trauma. The MEGX test and conventional static liver tests (bilirubin, aspartate aminotransferase, glutamate dehydrogenase, and factor V) were performed on days 1, 3, 5, and 7 after trauma. Patients were classified by a modified MOF score into a group without (n = 18) and a group with the MOF syndrome (n = 10). One patient who developed MOF on the basis of a bacterial septicemia was excluded from the general evaluation. No significant differences were observed in the MEGX values of the two groups on day 1. All patients who subsequently developed MOF, however, displayed a sharp decrease in their MEGX values between days 1 and 3. Analysis of the data using receiver operating characteristic (ROC) curves revealed that the results of the MEGX test on day 3 provided the greatest discriminating power between patients with and without subsequent MOF. A cut-off MEGX value of 30 micrograms/L on day 3 was associated with a prognostic sensitivity of 89% and a prognostic specificity of 94%.

Evaluation of Static Capacity of Deep Foundations from Statnamic Testing

Abstract A new method of load testing, called statnamic, is evaluated with respect to conventional methods of static load testing. Case histories are examined that provide a basis for comparison of static capacity as estimated from statnamic measurements with that of conventional load-deflection measurements. When evaluated using the simple procedure proposed by Middendorp, the statnamic method is shown to predict load-deflection response that is relatively close to that measured with conventional static load tests in most cases. Comparisons with conventional static load tests outlined in this paper suggest that excellent agreement can be obtained in sandy soils, but that the current evaluation procedure may tend to overpredict capacity by as much as 30% in stiff, overconsolidated clays.

Strategies Employed to Determine the Acute Aquatic Toxicity of Ethyl Benzene, a Highly Volatile, Poorly Water-Soluble Chemical

Studies are described in which ethyl benzene (EB) was tested to determine its acute toxicity to three marine organisms, Atlantic silversides (Menidia menidia), mysid shrimp (Mysidopsis bahia), and diatoms (Skeletonema costatum), and to one freshwater algae (Selenastrum capricornutum). The respective 96-hr median lethal concentration (LC50) values and 95% confidence intervals for EB in the flow-through studies with fish and mysid shrimp were 5.1 (4.4-5.7) mg/liter and 2.6 (2.0-3.3) mg/liter. While the 96-hr median effective concentrations (EC50′s) for growth inhibition and 95% confidence intervals for the static studies with diatoms and algae were 7.7 (5.9-10.0) mg/liter and 3.6 (1.7-7.6) mg/liter, respectively. Problems were encountered in all four studies as a result of the high volatility and poor water solubility of EB in water and an apparent "salting out" effect noted in seawater. This effect was found particularly true in the diatom and algae studies where the salinity was increased with the addition of culture medium. Measures are described which were used to overcome this stability problem with EB. These included sealing the test systems tight without any air spaces to prevent the collection of EB vapors. Also, increased mixing of EB in the test solutions was found to be essential in the flow-through studies to maintain stable levels. In the case of the diatom and algal studies, since current EPA test guidelines were judged to be inadequate to overcome EB volatility from the test medium, a new closed test system had to be developed and employed, after validation with a nonvolatile reference toxicant in the new and conventional static test systems. The results of these studies indicate that previous reports underestimated the potential acute aquatic toxicity of EB by at least one order of magnitude. The implications of these findings are discussed in relation to the potential environmental impact of EB and the resultant regulatory actions.

Viscoelastic Properties of Stiff Joints: A New Approach in Analyzing Joint Contracture

The purpose of this study was to analyze the joint stiffness after immobilization in a rat's lower extremity model. Rat knee joints were surgically immobilized in a full flexed position for periods of up to 7 weeks with or without intra-articular intervention. The biomechanical analysis was assessed by measuring the bone-joint-bone sample as a cantilever. Measurement was performed with (a) knee flexion angle with gravity, (b) fast Fourier transform analysis of time-dependent mechanical noise with random frequencies, and (c) dynamic stiffness and loss tangent with sinusoidal vibration at a certain frequency. The results showed that the conventional static mechanical test could not detect the intraarticular changes of the whole knee joint. The measurement of the viscoelastic properties covering wide frequencies revealed that an accurate change occurred.

Pre- and post-transplant assessment of liver function in paediatric liver transplantation.

The pre-operative risk of paediatric liver transplantation candidates (n = 41) was assessed in a prospective study by means of clinical symptoms, conventional static and liver blood flow dependent dynamic liver function tests. Nine patients died during the 365-day waiting period. The data were subjected as covariates to a survival analysis in the Cox proportional hazards model. There was a significant relationship between the results of mono-ethylglycinexylidide (MEGX) formation and ICG test and the 365-day survival rate. In the stepwise analysis, none of the remaining parameters improved the predictive ability when added to the dynamic liver function test results. The assessment of post-transplantation liver function was studied in 27 patients during the first 28 postoperative-day period. In addition, liver function was studied in a cross-sectional study 1-7 years after successful liver transplantation in children with complete or partial rehabilitation. In the early postoperative period severe organ damage was indicated by both static and dynamic liver function tests. In the later course after transplantation no deterioration of liver function measured with MEGX formation was to be observed. These findings demonstrate the usefulness of dynamic liver function tests in the pre- and post-transplant assessment of liver function.

Dynamic analysis of piled foundations using the CAPWAPC method : Davis, R A; Mure, J N; Kightley, M L Ground EngngV20, N8, Nov 1987, P16–22

This is the first of two complementary papers dealing with the dynamic analysis of piled foundations. It shows how wave propagation affects pile driving and gives an explanation of the capwapc (case pile wave analysis program -continuous version) program. Typical pile test results are also given. The equations used herein to explain capwapc were taken from an unpublished report by rausche,f of pile dynamics inc. With this technique it is possible to test a large number of piles on a given site with relative ease, and the results give more information than can be obtained from a conventional static load test. In particular, knowing the distribution of soil resistance in a pile should augment initial calculations. The next paper will describe some case histories in a range of soils. (TRRL)

Impact behaviour of concrete beams

An instrumented impact machine was used to carry out impact tests on concrete beams, 100×125 mm in cross-section and 1400 mm long. The simply supported beams were struck at their midpoints by a 345 kg mass impact hammer, dropped from various heights. The instrumentation included strain gauges mounted on the striking end of the hammer, strain gauges mounted on one support anvil, and three accelerometers placed at various locations along the beam. The data were collected using a 5-channel data acquisition system. Normal strength, high strength, and fibre reinforced concrete beams were tested. In general, it was found that the properties of concrete under the high stress rates associated with impact loading could not be predicted from conventional static tests.

A Liquefaction Test without Membrane Penetration Effects

A test system is devised to minimize detrimental effects of membrane penetration on the undrained shear strength of granular soils. The system constituting an electropneumatic closed-loop can compensate for volume changes caused by membrane penetration in real time so that the constant volume of soil skeleton is maintained. It can readily be coupled to any conventional static or cyclic shear test apparatus. In order to evaluate effectiveness of the system, cyclic triaxial tests were performed on specimens 75 mm in diameter either with or without the system. Resulting pore pressure responses and liquefaction strength curves for specimens with and without membrane compliance are compared, and the effects of membrane penetration are discussed. The test results revealed that, while the liquefaction characteristics of a fine sand with a mean grain size of 0.17 mm were not affected significantly by membrane penetration, the cyclic shear stress ratios to cause liquefaction for a coarse sand with a mean grain size of 1 mm were overestimated by about 30% as a result of membrane penetration. These results are consistent with an analytical estimation by other investigators, indicating satisfactory performance of the system in liquefaction tests.

A realistic computer-based fatigue comparison of spheroidal graphite cast iron and cast steel

Loads measured in a wheeled loader during service are used to compare two casts of SG iron with a cast steel to BS 592 grade A. Fatigue lives are predicted using computer based analytical methods. The conclusions reached are contrasted to those inficated by the more conventional static and fatigue tests. The suitability of SG iron as a material for cast axle housings is demonstrated.

鋼の引張圧縮塑性疲労試験

Fatigue failure of materials in the plastic range is considered to have an increasingly important significance nowadays, since the results obtained from these investigations provide the fundamental data not only for the design of some pressure vessels, but also for the study of thermal fatigue failure of materials. Several experimental results have been reported concerning the fatigue strength of some materials in the plastic range at room and elevated temperatures.We also planned these tests, and in the first place constructed a new device that made possible to carry out the completely reversed axial fatigue test with a conventional static testing machine. This device is necessary in most cases of this type of experiments, because the conventional static testing machine can not provide the tensile and compressive load to a specimen cyclically.Secondly, we made two types of experiments with low carbon steel using this device at room temperature-constant strain range test and contstant stress range test.The stress and the strain characteristics in the respective tests were compared in detail, and discussions were made concerning some hypotheses in order to interpret the relationship between these tests.The main results are as follows:(1) In the constant strain test the maximum tensile and compressive stress increase with the number of cycles due to the strain hardening effect. But in the constant stress test the mean tensile strain increases gradually with the number of cycles regardless of the initial loading directions'-tension or compression.(2) The true stress based on the actual cross sectional area must be considered when a discussion is made about the shape of stress-strain curve especially in the case of high stress or high strain conditions.(3) The total strain given to the specimen during the period up to the failure is found to be the most important factor affecting the fatigue failure in the plastic range. With this total strain we can interpret the respective test results of constant strain and constant stress together.