Drying Of Specimens Research Articles

Drying properties of Sentang (Azadirachta excelsa) dried under different temperatures

In this study, we investigated the drying properties of Sentang (Azadirachta excelsa) dried at different temperatures. Sentang tree planted in Kelantan, Malaysia, was used in this study. Drying specimens with dimensions of 30 ×150 × 500 mm were dried under air-drying conditions, a constant temperature of 60, 80, 100, and 120 °C until the moisture content (MC) of the specimens reaches an equilibrium moisture content (EMC) at each drying condition. The drying properties of the specimens were then examined. The results confirmed that drying temperature had a significant effect on drying time. As expected, drying Sentang under air-drying conditions demanding considerable time than the other drying conditions.

The effects of drying temperatures on preservative retention and penetration of some Malaysian fast-growing species timbers

This study was conducted to investigate drying properties of some Malaysia fast-growing species timbers exposed to drying under different temperatures, and evaluated the effects of these drying temperatures on preservative retention and penetration of the dried timbers. Four Malaysian fast-growing species, namely acacia (Acacia mangium), rubberwood (Hevea brasiliensis), sentang (Azadirachta excelsa), and kelempayan (Neolamarckia cadamba) obtained from a local plantation in Kelantan, Malaysia were used in this study. Drying specimens with dimension of 30 × 150 × 500 mm were dried under air-drying condition, a constant temperature of 60, 80, 100, and 120 °C until the moisture content of the specimens reaches an equilibrium moisture content at each drying condition. The drying properties of the specimens were then examined. After drying, stick specimens with a dimension of 20 mm (radial) × 20 mm (tangential) × 110 mm (longitudinal) obtained from the heartwood of the drying specimen were immersed in cupper azole (CuAz) wood preservative solution for 10 minutes under normal atmospheric pressure for rubberwood and kelempayan, and 30 minutes for acacia and sentang. Retention and penetration of the specimens were evaluated. The results confirmed that drying temperature had a significant effect on drying time. Drying under air-drying condition demanding considerable time, particularly drying acacia and sentang under air-drying condition required longer drying time than the other timber species. Drying temperature also had significant effects on preservative retention of all timber species, except kelempayan. The results demonstrated that preservative retention of all timber species tends to increase as drying temperature increased. In addition, high-temperature drying gives a positive effect on preservative penetration. Drying acacia under temperature of 100 °C could maintain a higher percentage of preservative coverage area until a sufficient depth from the penetration surface. This finding suggests that high-temperature drying is more desirable for better preservative retention and penetration of the specimens used in this study.

A viscoelastic poromechanical model for shrinkage and creep of concrete

Long-term delayed strain of concrete impacts the lifetime of civil engineering structures such as dams, nuclear power plants, nuclear waste storage tunnels or large bridges. In design practice, the long-term delayed strain of concrete is decomposed into four components: autogenous shrinkage, basic creep, drying shrinkage and drying creep. The four components are first computed separately and then summed up to obtain the total delayed strain of concrete, without wondering about any potential correlation between them. In this work, we aim at modeling the total delayed strain in a unified manner, without assuming this decomposition a priori. Such model is derived in the framework of viscoelastic poromechanics. The influence of relative humidity on the creep properties is taken into account. We assume that drying creep is due to the fact that the mechanical consequences of capillary effects are larger in loaded drying specimens than in non-loaded drying specimens. The model is validated by comparing the prediction with experimental results of delayed strain from the literature and discussed with respect to existing models.

Testing Study on the Effects of Water Content on Permeability for Coal

To obtain the effects of water content on the permeability of coal, briquette specimen were obtained from Wulong Mine, Liaoning Province. The permeability of the air drying, bounding water and saturating specimens were tested with self-made equipment respectively, and the effects of water content on permeability for coal were studied. The results showed that: (1)The permeability of specimens decreases with confining pressure increasing, and the air drying and bounding water specimens take on obvious slippage effect. However the saturated specimens never take on slippage effects. It is because the channels of saturated coal sample are occupied by water. When the gas goes through specimens, gas never is absorbed. Collision between gas and the channel wall decreases, and the slippage effect disappears. (2) With water content increasing, the permeability of specimens decreases. (3)The permeability of specimens increases when pore pressure increases.

Salt drying: a low‐cost, simple and efficient method for storing plants in the field and preserving biological repositories for DNA diversity research

Although a variety of methods have been optimized for the collection and storage of plant specimens, most of these are not suited for field expeditions for a variety of logistic reasons. Drying specimens with silica gel in polyethylene bags is currently the standard for field-sampling methods that are suitable for subsequent DNA extraction. However, silica-gel repositories are not readily available in remote areas, and its use is not very cost-effective for the long-term storage of collections or in developing countries with limited research budgets. Salting is an ancient and traditional drying process that preserves food samples by dehydrating tissues and inhibiting water-dependent cellular metabolism. We compared salt and silica-gel drying methods with respect to dehydration rates overtime, DNA quality and polymerase chain reaction(PCR) success to assess whether dry salting can be used as an effective plant preservation method for DNA analysis. Specimens from eleven plant species covering a variety of leaf structures, leaf thicknesses and water contents were analysed. Experimental work indicated that (i) levels of dehydration in sodium chloride were usually comparable to those obtained when silica gel was used, (ii) no spoilage, fungal or bacterial growth was observed for any of the species with all drying treatments and (iii) good yields of quality genomic DNA suitable for PCR applications were obtained in the salt-drying treatments. The preservation of plant tissues in commercial table salt appears to be a satisfactory, and versatile method that may be suitable in remote areas where cryogenic resources and silica repositories are not available.

Restrained concrete shrinkage in composite trusses

An analytical approach to compute restrained shrinkage effects on composite concrete deck – steel truss members is presented and validated using strains and deflections obtained by Brattland and Kennedy, who in 1986 tested two full-scale (11.8 m × 2.35 m in plan) composite trusses and companion drying specimens for approximately 90 d. The test-to-predicted ratios for these quantities are excellent, with a mean value of 0.89 and a coefficient of variation of 0.11. It is also demonstrated that (1) single test specimens with a single drying face exhibit a large gradient of free shrinkage strain across the depth of the specimen that must be properly considered in the analysis; (2) shrinkage parameters estimated using generic rules based on the concrete mixture composition are not realistic for the particular mix used by Brattland and Kennedy; and (3) history-independent analysis methods, as described in Annex H of CSA S16-09, do not accurately predict the slab strains and truss deflections observed by Brattland and Kennedy unless the variation of the free shrinkage strain with slab depth, tensile creep, and concrete modulus of elasticity are properly accounted for.

Hepatitis B assays in serum, plasma and whole blood on filter paper

BackgroundScreening and determining the immune status of individuals for hepatitis B is usually done by detecting hepatitis B surface antigen (HBsAg) and hepatitis B surface antigen-specific antibodies (HBsAb). In some countries with the highest viral burden, performing these assays is currently impractical. This paper explores the use of filter paper as a blood specimen transport medium.MethodsSamples, chosen from routine clinical laboratory pool, were applied and dried onto filter paper. Eluates, from the paper samples, were analyzed as routine clinical specimens on ADVIA Centaur 5634® immunoassay analyzers using the standard HBsAg and HBsAb kits. Dried blood samples were subjected to a range of environmental conditions in order to assess stability.ResultsAfter drying and elution the assays showed linearity and precision comparable to clinical assays performed on fresh serum. Elutions at various times during a 149 day incubation period showed very little variability in the Index numbers. All analytes were temperature stable except for a decrease in the HBsAg signal at 42°C.ConclusionsFilter paper is an acceptable storage and transport medium for serum to be used in the detection of hepatitis B markers if atmospheric variability can be controlled. HBsAg, HBsAb and HBcAb are all stable for at least five months under storage conditions below room temperature. Drying specimens, particularly serum, on filter paper at remote locations, offers a reasonable solution to the problem of hepatitis surveillance in underdeveloped regions, although some attempt at temperature control might be desirable.

An Evaluation of Several Techniques for Measuring Air-void Content in Asphalt Concrete Specimens

Abstract Precise and accurate measurement of air-void content is critical to the evaluation of asphalt-aggregate mix specimens taken in the field or compacted in the laboratory. It is an integral part of the performance-based testing and analysis methods developed by the Strategic Highway Research Program Contract A-003A (SHRP A-003A). Standard methods for drying specimens after coring and/or cutting from a larger compacted mass, and for measuring bulk specific gravity present problems for testing of the same specimen using equipment developed by SHRP A-003A, or whenever the specimen must be fixed to the testing equipment by means of an adhesive. This paper presents a comparison of the standard methods of air-void content measurement, measurement of bulk specific gravity using unsealed specimens and using specimen sealed with paraffin wax (ASTM D 1188, Test Method for Bulk Specific Gravity and Density of Compacted Bituminous Mixtures Using Paraffin-Coated Specimens), with three alternative methods for sealing the specimen: dusting with zinc stearate powder, wrapping with a waxy elastic paper called Parafilm™ (American National Can), and covering with a rubber membrane. The results indicate that each of the methods produces different measured air-void contents. The waxy elastic paper results were closest to those obtained from specimens sealed with paraffin, and it is suggested that this is a suitable alternative to paraffin wax when the specimens have smooth (cut/cored) surfaces and are to be tested for performance afterward. The use of an air gun to dry specimens after coring and/or cutting was compared with the standard oven-drying method (ASTM D 2728, Practice for Paving Uses and Application Temperatures for Road Tars). It was found that the use of a 210 kPa (30 psi) air gun produced similar results to those found with the standard method and was nondestructive, thus allowing further testing of the specimen.

Notes on Suaeda Forssk. ex Scop. Studies in the Chenopodiaceae of Arabia: 2

sDecies names. The genus Suaeda comprises about 75 species which are usually found on sandy and saline sea coasts, inland salt marshes and various desert soils and salt steppes mainly in the northern hemisphere; some are subcosmopolitan. The taxonomy of Suaeda is not easy since herbarium specimens lose some characters upon drying and sterile specimens are usually difficult to identify. Therefore, field experience and field notes are most helpful in solving some taxonomic problems. Another difficulty is that few studies, or probably none at all, are made on the entire range of the widespread species which, particularly in arid regions, exhibit diverse seasonal life forms due to erratic rainfall and overgrazing. As a result, some of these life forms are described as new taxa and we are left with more names than species. The following notes, on some Suaeda species known from Arabia, are made to elucidate some of the taxonomic and nomenclatural problems, based on the study of ample material from BM, C (Herbarium Forsskal), E, K and KTUH, as well as on field experience in Arabia and other parts of the Middle

Creep and creep recovery of plain concrete as influenced by moisture conditions and associated variables

Synopsis Experiments designed to investigate the effects of moisture content, condition of the cement gel, time of loading and time of unloading upon the creep and creep recovery of sealed and unsealed concrete specimens are described. Comparisons are made between the creep and creep recovery responses of specimens sealed immediately after curing and of unsealed specimens. The results of the experiments carried out on the drying (unsealed) specimens were easily predictable by existing theory. However, the experiments performed on the sealed specimens produced data not so easily explained. For example, under certain conditions, the creep of unsealed specimens was less than that of sealed specimens, and a period of time during which the creep potential of sealed specimens increased with age at time of loading was observed. These results are discussed in terms of the major variables affecting the creep of concrete: the degree of hydration at the time of loading, the amount of water present and not chemically combined at the start of loading and while the specimen is under load, and the amount of m icro cracking developed in the system before and during the time under load.

Some Rambling Notes on Collecting and Preserving Herbarium Specimens. V. Drying Specimens (Continued)

Some Rambling Notes on Collecting and Preserving Herbarium Specimens. V. Drying Specimens (Continued)