Modified Test Method Research Articles

Evaluation of Setting Time in Ultra High Performance Concrete

Ultra high performance concrete (UHPC), characterized by a high strength and high ductility, is also subjected to large shrinkage due to its low water-to-binder ratio and its large content in high fineness materials. The large amount of autogenous shrinkage of UHPC can induce crack on structural member when it was restrained with reinforcement and form. However, shrinkage of UHPC in plastic state is not generating confining stress, which is the main cause of initial crack. Normally, the setting time in concrete is an index to distinguish shrinkage which occur confining stress or not. An estimation of setting time is conducted in compliance with ASTM C 403 till now however, that test standard reveals error of results due to discordance of test condition as following with concrete type. This study therefore evaluated setting time of UHPC through the modified test method which was proposed by KICT. Test results and analyses proved a discrepancy of setting time between ASTM and proposed method. The proposed method put faith in evaluation of setting time in accordance with UHPC.

Long-term monitoring of environmental change in German towns through the use of lichens as biological indicators: comparison between the surveys of 1970, 1980, 1985, 1995, 2005 and 2010 in Wetzlar and Giessen

In the years 1970, 1980, 1985, 1995, 2005 and 2010, lichen mapping in the towns of Wetzlar and Giessen in Hesse was performed. The aim was to show the effects of immission load. Despite the application of modified test methods during the study period, the results can still be compared directly because they could be adapted to the requirements of the guidelines of the Association of German Engineers. Even the earlier study results could be interpreted partly within the scope of the guidelines. Parallel to the lichen mapping, comparative examinations of pH on tree bark were carried out. In both towns, the pH of the tree bark has been increasing continuously, presently almost reaching pre-industrial values. The increase was stronger in Wetzlar than in Giessen. In 1970, the lichen vegetation showed a complete depletion. Since then the number of species has risen significantly. This development happened faster and more intensely in Wetzlar. The comparison of the lichen vegetation between 1970 and 2010 also shows an increased existence of species that are favored by hypertrophic air contaminants. In the 2010 survey, some species considered as being promoted by global warming were found for the first time. The increase of the bark pH can be explained by the decreasing acid pollution, primarily SO2. This is also assumed to be the main cause for the increasing number of lichen species. An explanation for Wetzlar's advantage is that the acid pollutants had been neutralized by a local industrial emittent of lime dust. With the reduction of dust emissions in Wetzlar due to the installation of filters, the bark pH in both towns steadily converged in the reference period. An examination of pre-industrial lichen studies shows that in both towns the original state of lichen vegetation has not been restored yet.

An improved test method and numerical analysis for crack opening resistance of FRC round determinate panels

This paper presents a numerical analysis of a material test program investigating the crack opening properties of fibre reinforced concrete (FRC) round determinate panels (RDP). The objective of this research is to set up a modified RDP test method to improve the current ASTM C1550 test method for FRC and fibre reinforced shotcrete (FRS) composite. By this test method, a kind of light small-diameter panels are applied and more crack information can be obtained by a new rotation angle measuring technique. It is shown that this modified test method can be used to effectively evaluate the crack opening resistance of FRC. The finite element analysis was then performed to clarify the crack propagations and failure mode of FRC RDP panels. It helps establish a reasonable theoretical method to predict the structural response of RDP, combining with this modified testing technique.

Aerodynamics and Performance Verifications of Test Methods for Laboratory Fume Cupboards

The laser-light-sheet-assisted smoke flow visualization technique is performed on a full-size, transparent, commercial grade chemical fume cupboard to diagnose the flow characteristics and to verify the validity of several current containment test methods. The visualized flow patterns identify the recirculation areas that would inevitably exist in the conventional fume cupboards because of the fundamental configurations and structures. The large-scale vortex structures exist around the side walls, the doorsill of the cupboard and in the vicinity of the near-wake region of the manikin. The identified recirculation areas are taken as the 'dangerous' regions where the risk of turbulent dispersion of contaminants may be high. Several existing tracer gas containment test methods (BS 7258:1994, prEN 14175-3:2003 and ANSI/ASHRAE 110:1995) are conducted to verify the effectiveness of these methods in detecting the contaminant leakage. By comparing the results of the flow visualization and the tracer gas tests, it is found that the local recirculation regions are more prone to contaminant leakage because of the complex interaction between the shear layers and the smoke movement through the mechanism of turbulent dispersion. From the point of view of aerodynamics, the present study verifies that the methodology of the prEN 14175-3:2003 protocol can produce more reliable and consistent results because it is based on the region-by-region measurement and encompasses the most area of the entire recirculation zone of the cupboard. A modified test method combined with the region-by-region approach at the presence of the manikin shows substantially different results of the containment. A better performance test method which can describe an operator's exposure and the correlation between flow characteristics and the contaminant leakage properties is therefore suggested.

Colour-coded pellets increase the sensitivity of the staircase test to differentiate skilled forelimb performances of control and 6-hydroxydopamine lesioned rats

The Montoya staircase test has previously been used to study the skilled forelimb performance of mice and rats following lesions and cell implants in different parts of the central nervous system. Here we describe a modification of the original test design which introduces differently coloured food pellets for each step, and present the results of the new and modified method. In this study unilaterally 6-hydroxydopamine (6-OHDA) lesioned rats and healthy control rats were used. The new evaluation of reaching and grasping movements takes into consideration the various levels of reaching difficulty. The coloured food pellets code for different steps of the staircase. The comparison between the original versus the modified test methods revealed significant differences most prominently on the lower steps. It is important to notice that the pattern of grasping movements in the hemiparkinsonian rats changes from precise reaching (prior to lesion) to shuffling and unsuccessfully trying to reach pellets. The observation of this change in behaviour would not have been obtained through the evaluation of the original staircase test. In summary, the modified staircase test introduces a colour-coded pellet system which obviously increases the test sensitivity and discloses new insights into the skilled forelimb use in a rat model of Parkinson's disease. It may therefore become a valuable tool in future studies related to plasticity-induced changes in skilled forelimb reaching and grasping movements.

Colour parameters, whiteness indices and physical features of marking paints for horizontal signalization

The present paper describes the assessment of colour parameters of industrial paints for horizontal signalization (designed as POM S1 and POM S2 / ZEB 1 and ZEB 2) of white colour hue, coming from two different producers ("Pomoravlje" and "Zorka") with reference to an independent sample (IND 0) and some physical properties of each sample. Colorimetric characterization of samples was performed using a reflectance spectrophotometer "Update Colour Eye 3000". Standard and modified test methods (ASTM) were performed to establish physical properties of the paints. The industrial paints show better values for the investigated parameters and properties and satisfy standards prescribed by law. POM S2 sample with dry film thickness, similar to the same of other samples, provides the best physical features maximizing quality and minimizing protection cost.

Effect of solidification mode and morphology of microstructure on the hydrogen content of duplex stainless steel weld metal

The evolution rate of hydrogen from a duplex weld depends on sample geometry, temperature and microstructure. These factors have important consequences for the determination of hydrogen in duplex stainless steel welds. Because of the low hydrogen diffusibility and high hydrogen solubility in austenite, a standard method (BS 6693: 1988) which existed to determine the hydrogen content of ferritic steel welds as a means of assessing welding consumables, is not suitable for duplex welds. As a result of extensive research, a modified test method has been used involving encapsulation of the weld sample in Pyrex, evolution at 400 °C for 24 h, and followed by hydrogen analysis in an Oerlikon/Yanaco gas chromatograph. In this present work, the effect of solidification mode and microstructure on weld hydrogen content, and the evolution of hydrogen from such welds has been investigated by using experimental electrodes which are designed to give varying ferrite/austenite ratio in the welds. It was found that the measured weld hydrogen contents were almost constant since they arose from the flux/binder combinations which were the same for each type of experimental electrodes. Thus, the potential hydrogen from each type was the same and similar amounts became trapped during the rapid solidification of the weld pool, irrespective of final ferrite content.

Comparison of thermal expansion of wood and epoxy adhesives

and Iroko, Clorophora excelsa) and four different epoxy resins have been compared using a modified test method that allows for nearly iso-hygric conditions of the wood specimens. Minor differences in TEC have been observed between wood in the transversal-to-the-grain direction and an experimental epoxy adhesive, which is considered highly compatible with wood on the basis of mechanical and ageing tests. Other commercial epoxy adhesives show greater differences in terms of TEC and a proportionally decreasing mechanical compatibility. According to these results, the evaluation of thermal properties can be considered very useful for a modelling approach to predict the long term behaviour of wood-epoxy adhesive interface.

215 Estimation of Longitudinal Tensile Strength in Filament Wound Pipe using Notched Specimen

For the longitudinal tensile strength of filament wound pipes of glass fiber reinforced plastics (GFRP), Japan Industrial Standard K 7033 (JIS K 7033) was established in 1998,where three kinds of test methods (method A, B and C) were recommended for determining the tensile strengths. The objectives of this study were to compare the tensile strengths measured by each test method and to check whether each test results were acceptable or not for the modified test methods. The longitudinal tensile tests were conducted based on the JIS K 7033. For specimen geometry, a strip cut in the longitudinal direction of the pipe was used in method A, method B used a full section of the pipe and method C used a notched rectangular plate cut from a pipe wall section, so that two of the sides were parallel and the other two sides were at right angles to the longitudinal axis of the pipe. It was found that the three tensile strengths often did not agreed with each other within lower winding angles, and method C agreed with method B within higher winding angle. We discussed the accuracy of each test method, which was proposed as the simplified method to obtain the longitudinal tensile strength of the filament wound pipes.

Test methods for a reliable assessment of water-borne paints for exterior wood protection

Water-borne paint systems, which are applied in a relatively wet season, may cause an accumulation of water in the wooden substrate. This is exacerbated by an increase in moisture-barrier properties due to the leaching of water-soluble components, and is further promoted by the increasing barrier properties under relatively dry external conditions. Recent tests with four commercially available paint systems show an increase in μ-value with a factor 2.4 to 3.8, after a leaching period of only two weeks. Existing test methods and standards do not take sufficient consideration of the effects of leaching on the moisture barrier properties. The reliable assessment of the quality of water-borne paint systems for exterior wood protection needs new or modified test methods and standards. Mathematical models have to be developed to translate laboratory test results in to different practical conditions, climates and timber dimensions.

Test methods and data on the mechanical properties of protective oxide scales

The present paper describes the key mechanical properties of oxide scales with regard to model equations and investigation methods. Modified test methods are introduced for the determination of values describing scale failure, growth stresses in oxides and creep of the scales. Furthermore, a summary of scale fracture data from the literature is given. As a conclusion it is discussed that failure strains of oxide scales can be estimated from the model equations and using basic mechanical property data like fracture toughness and geometrical scale parameters as physical defect size, interface roughness, scale thickness etc. without complicated mechanical tests. In the end a universal mechanical properties diagram is introduced, which describes fracture and creep behavior of the oxide scales.

The biological safety of condom material can be determined using an in vitro cell culture system.

Latex products have long been recognized as a cause of latex protein allergy. The increased usage of latex gloves, with the consequent increased occurrence of latex allergies appears to have escalated with increasing awareness of the transmission of HIV–AIDS and other infections. The use of condoms as a means to prevent the transmission of STD's (sexually transmitted diseases) and HIV–AIDS has been widely promoted. Although extensive testing is done to evaluate the physical quality of condoms, no information is available regarding the biological safety of condoms. This study was undertaken to determine the effects of short‐term exposure to physiological levels of condom surface material on cell viability (MTT assay) and cell growth (crystal violet assay). A direct contact cell culture testing method (FDA test method F813‐83 used to evaluate the cytotoxic potential of medical materials and devices) was used. The modified test method was found to be a sensitive test system for the evaluation of the biological safety of condoms. This study reveals the importance of evaluating the biological safety of all condoms that are commercially available, because of the potential health risk that may be associated with prolonged use of certain types of condoms.

Test methods and data on the mechanical properties of protective oxide scales

The present paper describes the key mechanical properties of oxide scales with regard to model equations and investigation methods. Modified test methods are introduced for the determination of values describing scale failure, growth stresses in oxides and creep of the scales. Furthermore, a summary of scale fracture data from the literature is given. As a conclusion it is discussed that failure strains of oxide scales can be estimated from the model equations and using basic mechanical property data like fracture toughness and geometrical scale parameters as physical defect size, interface roughness, scale thickness etc. without complicated mechanical tests. In the end a universal mechanical properties diagram is introduced, which describes fracture and creep behavior of the oxide scales.

Factors Influencing Flow and Strength of Standard Mortars and Reappraisal of ASTM Test Methods for Fly Ash

Abstract Modified Test Methods for Sampling and Testing Fly Ash or Natural Pozzolans for Use as a Mineral Admixture in Portland-Cement Concrete (ASTM C 311) Pozzolanic (Strength) Activity Index tests with five fly ashes and two portland cements were done to compare results with those of standard tests. When sand contents (at constant water and cement contents) were varied, strengths of 38°C cured mortars decreased (−30 to −50 kPa/g of sand added in mixes containing 1370 to 1570 grams of sand) for different cement/fly ash blends. When water contents (at constant sand contents) were varied, strengths varied (−125 to +190 kPa/mL), strengths tending to increase because of paste volume increases with water content. Flow of mortars in both kinds of tests increase nearly linearly with paste volume fractions; the slopes are related by a factor of 0.60 ± 0.04. Accelerated curing at 38°C for tests at 28 days usually yields higher relative strengths than after curing at 23°C for 91 days. Multiple linear regression equations using both kinds of test data are solved at specified flow and strength values to determine proportions and mortar volume yields. This more general performance test ranks fly ashes (or cementitious mixtures) by mortar volume yield at equal flow and strength, and is suggested as a candidate to replace the present Strength Activity Index test.

Probabilistic method to assess insulating link performance for protection of crane workers

Contact between cranes and transmission lines is the most frequent cause of accidents, which may lead to electrocution of an operator or rigger. This accident can be prevented by inserting an insulating link in the crane's cable. This paper analyzes currents during accidents and proposes a modified test method for contaminated insulating links. A new and better insulating link is also introduced. Flashover probability of contaminated insulator links is measured. The test results are evaluated with a new probabilistic method which leads to better assessment of link efficiency. The paper concludes that the risk of link failure cannot be determined without the new flashover probability measurement.

Further Development for Testing the Effects of Pesticides on Wolf Spiders

Based on preliminary guidelines of the "Biologische Bundesanstalt für Land- und Forstwirtschaft" (BBA, Germany) for testing the effects of pesticides on wolf spiders (genus Pardosa, Lycosidae, Araneae), two test series were carried out with the pesticides Karate (a.i. λ-cyhalothrin) and a noname product. At start of the test the pesticides were applied onto spiders and a sand substrate with an application apparatus. Thereafter, the mortality, the behavior, and the feeding rate were observed up to 14 days. Ninety-eight percent of the tested individuals belonged to the species Pardosa amentata. The results of the Karate experiments indicated a considerably higher reaction for males than for females. The aggression of the spiders proved to be a stress factor when the vessel was inhabited by more than one spider and caused higher mortality in individuals treated with pesticides. Spiders raised from cocoons in the laboratory were in general less sensitive than animals collected in the field and accustomed to laboratory conditions. Experiments performed with the noname pesticide in different seasons revealed that the sensitivity of the animals was influenced by their age. The parameters of mortality, behavior, and feeding rate proved to provide data adequate for evaluating the lethal and sublethal effects of the substances examined, The results suggest that the test method may be improved by (i) using spiders raised from cocoons in laboratory, (ii) using fine gauze to prevent the escape of food flies, (iii) testing in the same season when application of the pesticide is planned in the field, (iv) using one animal per test vessel to avoid cannibalism and intraspecific stress, (v) providing additional feedings to avoid cannibalism, and (vi) assessing effects of chemicals on both sexes separately. Summarized, the modified test method is suggested as an adequate method for testing the effects of pesticides on wolf spiders ( Pardosa sp.). Use of the test during the registration proceeding is proposed as part of the testing program for effects of pesticides on beneficial arthropods.

Complete stress — strain behaviour of high-strength concrete under compression

A series of compression tests were conducted on 3 × 6 in (76·2 × 152·4 mm) cylindrical specimens using a modified testing method that gave the complete stress–strain behaviour for high-strength concrete with or without tie confinements. Empirical equations are proposed to represent the complete stress–strain relationships of unconfined and confined high-strength concretes with compressive strength exceeding 10 kip/in2 (69 MPa). Various parameters were studied and their relationships were experimentally determined. me proposed empirical stress–strain equations are compared with actual cylinder tests under axial compression, and are found to agree well.

Review of imipenem.

Imipenem, a new carbapenem beta-lactam broad-spectrum antibiotic, is highly active in vitro against most aerobic and anaerobic gram-positive and gram-negative bacteria isolated from infectious diseases of human beings. Except for enterococci and methicillin-resistant staphylococci most gram-positive cocci are inhibited by less than 2 micrograms/ml. Although the MIC-90 of methicillin-resistant staphylococci may be less than 4 micrograms/ml, these bacteria are usually resistant to imipenem by modified testing methods. The enterococcus, S. faecalis, has an MIC-90 of less than 8 micrograms/ml but bactericidal concentration may be much higher. Most Enterobacteriaceae are highly susceptible to imipenem with MIC-90 of 0.5 to 2.0 micrograms/ml. Proteus species are less susceptible with MICs of 4 to 8 micrograms/ml. Isolates of P. aeruginosa have variable susceptibility with MICs ranging from 0.25 to 16 micrograms/ml. Pseudomonas maltophilia and P. cepacia are usually resistant to imipenem. Except for Clostridium species, most strict anaerobes are susceptible to less than 1.0 micrograms/ml of imipenem. When combined with cilastatin (1:1 ratio), the renal elimination of the active form is increased. The serum halflife in normal renal function is about 1 hour and increases to 3.4 hours in anuria. Major adverse effects are similar to those of cephalosporins except for seizures in some patients. Colonization with fungi and drug-resistant bacteria occurs in about 5% of imipenem-treated patients. Clinical studies have demonstrated efficacy in 79% to 96% of patients treated.

An improved torsional method for determining the fracture toughness of stiff materials and of adhesive joints

A simple modification is described of the Outwater torsion test method for determining the fracture energy of stiff materials and of adhesive joints. It permits large torsions to be applied and the corresponding torque to be simultaneously monitored. The modified test method can be used with specimens of simple rectangular shape and having a wide range of stiffness. As an example, the fracture energy is determined for molded rectangular bars of polystyrene having a wide range of thickness and of width.

Improvement of Patch Test Allergen Exposure by Short-Term Local Pressure

Since false-negative results in patch testing may be due to insufficient skin contact with the allergen during exposure, we tried a modified test method by initially applying standardized pressure (10-kg sand bag for 15 min) on the test patches. Tests were simultaneously performed in 50 patients with and without local pressure. Comparing the results of both methods and (in some cases) to those after stripping the horny layers, positive contact sensitivity reactions could more often be detected after initial application of pressure.