Strength Characterization of Soils’ Properties at High Strain Rates Using the Hopkinson Technique—A Review of Experimental Testing

The paper presents a review of crucial experiments and the latest publications, presenting the previous and current trends in experimental research in 2018–2021 in the area of soil dynamic interaction based on the Hopkinson bar technique. A review of investigated experimental test stands was made, in particular, cohesive and non-cohesive soil specimens prepared with different dimensions and densities. From this study, it can be concluded that the dynamic response of the soil depends on many factors, e.g., density, cohesion, moisture and grain structure of the soil specimen. There is still a noticeable interest in SHPB experiments performed in both 1D and 3D versions under modified conditions (frozen/heated soil specimen, different degree of water saturation content of the soil sample) in a wide range of strain rates 102–104 s−1, which is a large field for further research. The need to learn about the characteristics of various types of soil (both cohesive and non-cohesive) for the selection of structural design solutions for the protection elements of critical infrastructure was emphasized.

Application of Binding-Bonding technique for Plastic Solid Waste

Plastic solid waste management is amongst the most menacing issue covered across the globe. Plastic is the material with multiple usages, replacement of plastic is a solution to reduce plastic based pollution but this is not possible in order to gather the needs of humans. Natural resources are depleting worldwide at the same time the generated wastes are expanding substantially. The usage of plastic when looking to its degradation rate has calamitous difference, at present the conversion of plastic into cement can provide an upgrade to environment as well as economic benefits. In this present study the Plastic waste management was done at educational institution in order to manage the huge amount of plastic waste generated everyday by the affiliates.Utilization of plastic waste in preparation of paved blocks originated from the known mechanisms for production of bricks and fly ash blocks. Plastic serves as a bonding agent when heated. Soil serves as binding agent when mixed with melted plastic. Properties of sandy soil shows that after heating it changes the colour, becomes non-sticky, has no effect of weather, compressive strength increases and surface becomes hard. The method used in this study for preparation of blocks from plastic was hypothesized form the technique of production of bricks in which soil is mixed with bonding clay. Sandy soil and clay mixture serves good quality by providing less shrinkage. The aim of this study is to manage plastic waste from depleting the environment.

Relating sampling effort to the detection of spatial patterns of species richness in the soil seed bank of a mediterranean shrubland.

<p>Studying the soil seed bank is a time and space-consuming task, and therefore only a small fraction of the soil is sampled. It is then critical to optimize sampling effort to reliably estimate soil seed bank properties. Here, we test whether the spatial patterns of species richness in the soil seed bank differ under increasing sampling effort. For this, we used data of germination from soils in a mediterranean shrubland in Central Spain. Two data sets were used, one of the seedlings emerging after heating the soil to break dormancy, and one with the combined germinations of heated and non-heated soil subsamples. We simulated increased sampling effort with sample-based rarefaction curves, extrapolating the species richness corresponding to a 2x and 3x increase in the number of individuals (seedlings) per sample. We then analyzed the spatial pattern of the original and extrapolated species richness using linear regression and semivariograms. Species richness increased by 34% and 52% in the 2x and 3x estimations, however the spatial pattern of species richness remained largely unchanged. For the long-distance spatial pattern, the slope of the plot-scale trend (i.e., the regression coefficient) increased only slightly with increasing sampling effort, while the adjusted R-squared of the regression decreased with increasing sampling effort. For the short-distance spatial pattern we could only fit spherical model semivariograms to the data from soils exposed to a heat shock, and the intensity of the spatial pattern (spatial dependence) increased very slightly with increased sampling effort. These results suggest that even with a doubled or tripled sampling effort, as provided by the simulations, the spatial pattern of species richness would have remained unchanged. We argue that increased effort in detecting species in the seed bank needs not necessarily improve the detection of spatial pattern.</p>

Use of optical properties for evaluating the presence of pyrogenic organic matter in thermally altered soil leachates

Optical measurements reveal the presence of pyrogenic organic matter in laboratory heated soil leachates, indicating their potential for application in field measurements.

Thermoflavifilum aggregans gen. nov., sp. nov., a thermophilic and slightly halophilic filamentous bacterium from the phylum Bacteroidetes

A strictly aerobic, thermophilic, moderately acidophilic, non-spore-forming bacterium, strain P373T, was isolated from geothermally heated soil at Waikite, New Zealand. Cells were filamentous rods, 0.2–0.4 µm in diameter and grew in chains up to 80 µm in length. On the basis of 16S rRNA gene sequence similarity, strain P373T was shown to belong to the family Chitinophagaceae (class Sphingobacteriia ) of the phylum Bacteroidetes , with the most closely related cultivated strain, Chitinophaga pinensis UQM 2034T, having 87.6 % sequence similarity. Cells stained Gram-negative, and were catalase- and oxidase-positive. The major fatty acids were i-15 : 0 (10.8 %), i-17 : 0 (24.5 %) and i-17 : 0 3-OH (35.2 %). Primary lipids were phosphatidylethanolamine, two unidentified aminolipids and three other unidentified polar lipids. The presence of sulfonolipids (N-acyl-capnines) was observed in the total lipid extract by mass spectrometry. The G+C content of the genomic DNA was 47.3 mol% and the primary respiratory quinone was MK-7. Strain P373T grew at 35–63 °C with an optimum temperature of 60 °C, and at pH 5.5–8.7 with an optimum growth pH of 7.3–7.4. NaCl tolerance was up to 5 % (w/v) with an optimum of 0.1–0.25 % (w/v). Cell colonies were non-translucent and pigmented vivid yellow–orange. Cells displayed an oxidative chemoheterotrophic metabolism. The distinct phylogenetic position and the phenotypic characteristics separate strain P373T from all other members of the phylum Bacteroidetes and indicate that it represents a novel species in a new genus, for which the name Thermoflavifilum aggregans gen. nov., sp. nov. is proposed. The type strain of the type species is P373T ( = ICMP 20041T = DSM 27268T).

Meiothermus terrae sp. nov., isolated from a geothermally heated soil sample

A Gram-negative, aerobic bacterium, designated strain YIM 77755T, was isolated from a geothermally heated soil sample collected at Rehai National Park, Tengchong, Yunnan province, south-west China. Cells of the strain were rod-shaped and colonies were yellow and circular. Growth occurred in 0–1 % (w/v) NaCl, at pH 6.0–8.0 (optimum, pH 7.0) and at 35–55 °C (optimum, 50 °C). The predominant menaquinone was MK-8 and the DNA G+C content was 68.9 mol%. Major fatty acids (>10 %) were anteiso-C15 : 0 and iso-C15 : 0. The polar lipids consisted of an uncharacterized phospholipid and four glycolipids. Based on 16S rRNA gene sequence analysis, strain YIM 77755T formed a cluster with Meiothermus chliarophilus ALT-8T and showed the highest 16S rRNA gene sequence similarity to M. chliarophilus ALT-8T (98.23 %). DNA–DNA relatedness between YIM 77755T and M. chliarophilus DSM 9957T was 54.9±4.1 %. On the basis of the morphological and chemotaxonomic characteristics as well as genotypic data, it is proposed that strain YIM 77755T represents a novel species of the genus Meiothermus , named Meiothermus terrae sp. nov. The type strain is YIM 77755T ( = DSM 26712T = CCTCC AB 2012942T).