Prediction of Soil Properties from the Concepts of Energy Transfer in Dynamic Penetration Tests

Results from dynamic penetration tests are traditionally interpreted on the basis of empirical correlations, this being a frequent criticism to these tests. An alternative rational method of interpretation is proposed in this paper from which the energy delivered to the composition of rods is used to calculate a dynamic force that represents the reaction of the soil to the penetration of the sampler (Fd). Interpretation of soil properties both in sand and clay is based on this calculated dynamic force from which the internal friction angle and the undrained shear strength can be estimated. This is achieved from a simple combination of limit equilibrium analysis and cavity expansion theory. Case studies gathered from the Brazilian experience are reported in this paper to illustrate the applicability of the proposed approach.     

Determination of key diffusion and partition parameters and their use in migration modelling of benzophenone from low-density polyethylene (LDPE) into different foodstuffs

The mass transport process (migration) of a model substance, benzophenone (BZP), from LDPE into selected foodstuffs at three temperatures was studied. A mathematical model based on Fick’s Second Law of Diffusion was used to simulate the migration process and a good correlation between experimental and predicted values was found. The acquired results contribute to a better understanding of this phenomenon and the parameters so-derived were incorporated into the migration module of the recently launched FACET tool (Flavourings, Additives and Food Contact Materials Exposure Tool). The migration tests were carried out at different time–temperature conditions, and BZP was extracted from LDPE and analysed by HPLC-DAD. With all data, the parameters for migration modelling (diffusion and partition coefficients) were calculated. Results showed that the diffusion coefficients (within both the polymer and the foodstuff) are greatly affected by the temperature and food’s physical state, whereas the partition coefficient was affected significantly only by food characteristics, particularly fat content.     

UPLC-QTOF-MSE-based chemometric approach driving the choice of the best extraction process for Phyllanthus niruri

P. niruri extracts obtained by ultrasound-assisted extraction (UAE), pressurized liquid extraction (PLE), and conventional extraction (CE) were compared. The extracts produced by PLE had the highest phenolic content. In the principal component analysis, CE and PLE 120°C extracts formed a single group, separated from PLE 192°C and UAE extracts. The orthogonal partial least square discriminant analysis revealed geraniin, phyllanthusiin C, repandusinic acid A, and phyllanthusiin U as chemical markers in CE and PLE 120°C. PLE 192°C extract presented a high content of gallic acid and ellagic acid hexose, and UAE extract presented virganin and furosin as characteristic compounds.     

Apple Aminoacid Profile and Yeast Strains in the Formation of Fusel Alcohols and Esters in Cider Production

The amino acid profile in dessert apple must and its effect on the synthesis of fusel alcohols and esters in cider were established by instrumental analysis. The amino acid profile was performed in nine apple musts. Two apple musts with high (>150 mg/L) and low (<75 mg/L) nitrogen content, and four enological yeast strains, were used in cider fermentation. The aspartic acid, asparagine and glutamic acid amino acids were the majority in all the apple juices, representing 57.10% to 81.95%. These three amino acids provided a high consumption (>90%) during fermentation in all the ciders. Principal component analysis (PCA) explained 81.42% of data variability and the separation of three groups for the analyzed samples was verified. The ciders manufactured with low nitrogen content showed sluggish fermentation and around 50% less content of volatile compounds (independent of the yeast strain used), which were mainly 3‐methyl‐1‐butanol (isoamyl alcohol) and esters. However, in the presence of amino acids (asparagine, aspartic acid, glutamic acid and alanine) there was a greater differentiation between the yeasts in the production of fusel alcohols and ethyl esters. High contents of these aminoacids in dessert apple musts are essential for the production of fusel alcohols and most of esters by aromatic yeasts during cider fermentation.     

Composition,toxic and antinutritional factors of newly developed cultivars of Brazilian soybean (Glycine max)

Five different recently released Brazilian soybean cultivars (Bays, BR-10, Rio Balsas, Serido and Tropical) were compared for their proximate analyses and presence of antinutritional or toxic factors. As expected, the seeds are rich in proteins, varying from 360·7 to 485·4 g kg⁻¹ flour, and they also have a high amount of fat (from 183·0 to 215·3 g kg⁻¹ flour). Crude extracts from seeds of Bays, BR-10, Serido and Tropical were highly toxic to mice within 1–12 h, depending on the administration route (intraperitoneal, intramuscular or subcutaneous) and dose used while Rio Balsas was not. These acute effects were very similar to those produced by the soytoxin, a neurotoxin that has been recently purified from the commercial soybean sold in Brazil. The amount of trypsin inhibited in the presence of crude extracts ranged from 28·5 to 62·5 g kg⁻¹ flour. Urease was also present and the seed lectin agglutinated preferentially rabbit erythrocytes. A heat treatment at 92°C for 1 min destroyed completely the toxic activity while the haemagglutinating and trypsin inhibitor activities were abolished within 5 min. At these conditions urease was still active. Due to its high protein content, lack of soytoxin, and low levels of trypsin inhibitor, lectin, and urease it is suggested that Rio Balsas could be an alternative for breeding programmes aimed to improve the nutritional quality of soybeans. ©1997 SCI     

Spectrophotometry as a tool for characterizing durability of woven geotextiles

Geotextiles are used in numerous applications ranging from coastal hydraulic projects to geotechnical landfill projects. Durability studies are necessary for the sizing of these structures since these projects are subject to aggressive weathering. Therefore, it is important to be able to rapidly evaluate the rate of degradation of the geotextile, without detriment to the project. For traditional tests of geosynthetics, large areas must be exhumed, therefore a test which makes use of small specimens is proposed: spectrophotometry. The procedure proposed here makes use of electromagnetic radiation to evaluate the degradation of woven geotextiles by means of analysis of ultraviolet and infrared absorption. The aim of this study is to demonstrate the analysis of geotextile materials by spectrophotometry, making comparisons between laboratory and field degradation. The analyses and correlations were demonstrated to be satisfactory for characterization of degraded geotextiles. The results, with respect to both the absorbance of ultraviolet and transmittance of infrared, yielded both qualitative and quantitative characterizations of the behavior of the studied material. Therefore, spectrophotometry may be considered viable alternative for evaluating the characterization of durability in exhumed samples.     

Studies of edible Amazonian plants. Part 5: Chemical characterisation of Amazonian Endopleura uchi fruits

The chemical composition of the fruit pulp of Endopleura uchi growing in the Brazilian Amazon was investigated for characterisation and evaluation of its nutritional value. According to the analyses performed, it possesses a considerably high content of fat, characterised by a high oleic acid content. The fruit also contains remarkably high amounts of dietary fibres and phytosterols, as well as notable contents of vitamin C, vitamin E and minerals. In total, 42 volatile compounds could be identified by GC-MS in the fruit pulp aroma, which consisted mainly of the alcoholic compounds 3,3-dimethyl-2-butanol (18.8%) and eugenol (14.0%), as well as methyl and ethyl esters of fatty acids (18.5%).     

Microstructure and Heat Transfer Phenomena in Ceramic Thermal Barrier Coatings

Comparably thick Y₂O₃-partially-stabilized ZrO₂ thermal barrier coatings were deposited by two different techniques, air plasma spray (APS) and electron beam physical vapor deposition (EB-PVD), on the same type of substrate. Microstructure and grain texture, as studied by SEM and XRD, were markedly different. The complex microstructure of the APS coatings, made of curled lamellar grains, was replaced in EB-PVD coatings by long columnar grains, aligned along the growth axis, with strong grain texture. Average porosity and other average or intrinsic properties, such as density and specific heat, were nearly the same for all studied coatings; phase composition ranged between 0 and 6 wt% of the m phase in a prevalent t '-phase matrix. The main difference was in the shape and orientation of porosity with respect to the thermal flux direction, which was responsible for the different thermal diffusivity that was three times higher in EB-PVD than in APS coatings. An appropriate modeling of the heat diffusion process, including open and closed porosity with orientation and shape factors, could explain the observed diffusivity values.     

Novel experimental techniques to assess the time-dependent deformations of geosynthetics under soil confinement

A new experimental approach to assess the impact of soil confinement on the long-term behavior of geosynthetics is presented in this paper.The experimental technique described herein includes a novel laboratory apparatus and the use of different types of tests that allow generation of experimental data suitable for evaluation of the time-dependent behavior of geosynthetics under soil confinement.The soil-geosynthetic interaction equipment involves a rigid box capable of accommodating a cubic soil mass under plane strain conditions.A geosynthetic specimen placed horizontally at the mid-height of the soil mass is subjected to sustained vertical pressures that,in turn,induce reinforcement axial loads applied from the soil to the geosynthetic.Unlike previously reported studies on geosynthetic behavior under soil confinement,the equipment was found to be particularly versatile.With minor setup modifications,not only interaction tests but also in-isolation geosynthetic stress relaxation tests and soil-only tests under a constant strain rate can be conducted using the same device.Also,the time histories of the reinforcement loads and corresponding strains are generated throughout the test.Results from typical tests conducted using sand and a polypropylene woven geotextile are presented to illustrate the proposed experimental approach.The testing procedure was found to provide adequate measurements during tests,including good repeatability of test results.The soilegeosynthetic interaction tests were found to lead to increasing geotextile strains with time and decreasing reinforcement tension with time.The test results highlighted the importance of measuring not only the time history of displacements but also that of reinforcement loads during testing.The approach of using different types of tests to analyze the soilegeosynthetic interaction behavior is an innovation that provides relevant insight into the impact of soil confinement on the time-dependent deformations of geosynthetics.