Draft Genome Sequence of Leifsonia poae Strain BS71, Isolated from a Drought Microcosm

We report the draft genome sequence of Leifsonia poae strain BS71. This bacterium was isolated from a low soil moisture content model soil microcosm inoculated with forest soil that had been subject to chronic warming.

Regularities of Stress-Corrosion Cracking of Pipe Steel 09G2S at Cathodic Polarization in a Model Soil Environment

Peculiarities of corrosion-mechanical fracture of 09G2S pipe steel samples in the conditions of cathodic protection were investigated. It was established that depending on the level of protective potential, stress-corrosion cracking of pipe steel of a ferrite-pearlite class 09G2S can occur by different mechanisms. The range of protective potentials was determined, at which the anodic dissolution and hydrogen embrittlement occur simultaneously during the fracture of steel, namely from -0.85 V to -1.0 V. The existence of the above mechanisms is confirmed by the change in the strength and viscosity properties of the steel and the morphology of the fractures. For steels of other manufacturing technology and grades, these potential areas may differ.

ЗАКОНОМІРНОСТІ КОРОЗІЙНОГО РОЗТРІСКУВАННЯ ТРУБНОЇ СТАЛІ 10Г2ФБ У МОДЕЛЬНОМУ ГРУНТОВОМУ СЕРЕДОВИЩІ ЗА КАТОДНОЇ ПОЛЯРИЗАЦІЇ

Purpose. Investigate the regularities of corrosion cracking of 10G2FB steel under cathodic protection.Methodology. The following methods were used: slow strain rate, scanning electron microscopy, electrolytic hydrogenation, mass measurement.Results. The regularities of corrosion cracking of pipe steel 10G2FB in near neutral soil environment NS4 in the range of potentials from the corrosion potential to -1.2 V were investigated. According to the results of a complex of corrosion-mechanical, electrochemical and physical studies, it was found that with a shift in the cathodic polarization potential in the range of -0,75 V ® -0,95 V ® -1,05 V ® -1,2 V ® -0.95 V the coefficient of susceptibility of this steel to stress corrosion cracking KS increases correspondingly, 1,09 ® 1,11 ® 1,13 ® 1,26. The concentration of hydrogen which penetrating into steel at these potentials changes nonmonotonically: 0 ® 0 ® 0,057 ® 0,018 mol/dm3. The rate of residual corrosion with a potential shift in the series Еcor ® -0,75 V ® -0,95 V ® -1,05 V decreases first sharply, then slowly: 0.035 mm/year ® 0.005 mm/year ® 0.0009 mm/year ® 0.0004 mm/year, i.e. at high cathodic potentials, the applied polarization is spent on the decomposition of the aqueous electrolyte with the release of hydrogen, which penetrates into the steel and causes brittle cracking, which is confirmed by an increasing in the part of brittle fracture in the surface morphology of the specimens.Scientific originality. New results of fundamental research concerning the regularities of stress-corrosion cracking of ferrite-pearlite class steel of pipe assortment 10G2FB under conditions of cathodic protection in the range of potentials from the corrosion potential to -1.2 V have been obtained. It was revealed that a feature of the effect of cathodic polarization in the indicated range of potentials when assessing the tendency to stress corrosion cracking by the KS coefficient is an increasing in the relative narrowing and a decrease in the relative elongation, which generally indicates the embrittlement of the metal under the contact with corrosive medium and potential. Strength characteristics remain almost the same. The greatest tendency to stress-corrosion cracking is observed at a polarization potential of -1.0 V or more negative.Practical value. The developed methodology for a complex study of the regularities of stress- corrosion cracking was used for study of 10G2FB steel of the pipe assortment in a model soil environment NS4 under conditions simulating operating conditions. The new data obtained on the regularities of stress-corrosion cracking of steel will be useful for preventing the stress-corrosion cracking of main gas pipelines during operation.

Kalibrasi Model Soil Moisture Accounting dengan Software HEC-HMS di Stasiun Debit Pasir Pangaraian

This research aims to compare the results of the calibration of the Soil Moisture Accounting (SMA) model using Percent Error in Volume (PEV) and Peak Weighted Root Mean Square Error (RMSE). The SMA model calibration uses the HEC-HMS (Hydrologic Engineering Center – Hydrologic Modeling System). There are 12 calibrated parameters by automatic calibration. The input data are the area of ​​the watershed, daily rainfall, daily discharge data and climatological data. The data used is data from 2008 to 2017. The results show that PEV performance shows good results. While the RMSE showed poor results. PEV results are best at 7 years of calibration and 3 years of verification. The length of the calibration data has not affected the verification results.

Sustainable Restoration of Degraded Farm Land by the Sheet-Pipe System

For the sustainable restoration of wet farm land degraded by the climate change-induced rise of ground water level (GWL) and soil salinity etc., the sheet pipe system is one of the most useful technologies which reduces cultivation obstacles due to the poor drainage by controlling the rapid drainage function and enabling farmers to produce profitable crops. This system is characterized mainly as a perforated polyethylene rolled-band sheet 180 mm in width and 1 mm thick which is drawn into the subsurface layer while transforming a drainage pipe with φ = 50 mm. The major advantage of this system is that since the sheet pipe is installed without trenching, the disturbance of land is minimized and the construction period can be shortened to about 1/4 (which reduces the cost approximately by 50%). In this study, by using the sheet pipe installed miniature-type model soil box, the drainage capacity of the sheet pipe was confirmed as being the same as the pipe-shaped standard drainage pipes. Based on the observations of the saturated–unsaturated flow and the maximum lowering rate of GWL was predicted. Finally, at the farm land wherein the free board of the adjoining canal was limited, the effectiveness of the sheet-pipe system was confirmed.

Centrifuge study of seismic response of soil-nailed walls supporting a footing on the ground surface

Seismic design of soil-nailed walls requires demonstrations of tolerable ranges of wall movements, especially when a surcharge load exists near the wall. In this study, the effect of surcharge location on seismically induced wall movements was investigated using four centrifuge tests. The axial tensile forces, developed along the soil nails during the seismic loadings, were also measured during the tests. At 50g centrifugal acceleration, model tests represented a 12-m-high prototype wall reinforced with five rows of soil nails. To apply a surcharge stress of 30 kPa at the specified location relative to the wall for each model test, a rigid footing was placed on the soil surface. The model soil-nailed walls were subjected to three successive earthquake motions. Surprisingly, it was found that the model wall with the footing located behind the soil-nailed region experienced the largest seismic movements, even more than when the footing was directly behind the wall. Further, the tests showed that the lower soil nails played a key role in the wall stability during earthquake shaking, acting as a pivot for the pre-collapse cases tested, whereas the upper soil nails needed to be sufficiently extended to properly contribute to the seismic stability of the wall.

Spatial Distribution of Lead (Pb) in Soil: A Case Study in a Contaminated Area of the Czech Republic

For decades, the Příbram district in the Czech Republic has been affected by industrial and mining activities. These activities are important sources of heavy metal pollutants that are detrimental to soil quality. A recent study examined visible–near-infrared (VNIR), shortwave-infrared (SWIR) and X-ray fluorescence (XRF) spectroscopy to model soil lead (Pb) content in a selected area located in the Příbram district. Following that study, and using the same chemical and geographical data, we examined the spatial distribution of Pb content in the soil, with a combination of different traditional spatial analyses (Moran’s I, hotspot analysis, and Kriging) that were significantly validated. One of the novel points of this work is the use of the Getis–Ord hotspot analysis before the execution of a Kriging interpolation model to better emphasize clustering patterns. The results indicated that Pb was a spatially dependent soil property and through extensive in situ sampling, it was possible to generate a very accurate Kriging interpolation model. The high-Pb hotspots coincided with topographic obstacles that were modeled using topographic profiles extracted from the open-source Google Earth platform, indicating that Pb content does not always exhibit a direct relationship with topographic height as a result of runoff, due to the contribution of topographic steps. This observation provides a new perspective on the relationship between Pb content and topographic patterns.

A Study of the Frequency Domain Induced Polarisation Effects Displayed by Clay and by Cation Exchange Resin, Model Soil Systems

<p>Work is reported of the development of clay and resin model soil systems for the observation of induced polarisation phenomena. A measuring technique is developed to determine impedance spectra of such models over the frequency range of 10-3 to 10 4 Hz, and a variety of model cells tested varying such parameters as temperature, electrolyte type and concentration, and bead size of resin. An increase in impedance with decrease in frequency is observed, consistent with field observation of the induced polarisation phenomenon associated with moist, non-mineralised soils, and a number of empirical observations of the form of this are made.</p>

A Study of the Frequency Domain Induced Polarisation Effects Displayed by Clay and by Cation Exchange Resin, Model Soil Systems

<p>Work is reported of the development of clay and resin model soil systems for the observation of induced polarisation phenomena. A measuring technique is developed to determine impedance spectra of such models over the frequency range of 10-3 to 10 4 Hz, and a variety of model cells tested varying such parameters as temperature, electrolyte type and concentration, and bead size of resin. An increase in impedance with decrease in frequency is observed, consistent with field observation of the induced polarisation phenomenon associated with moist, non-mineralised soils, and a number of empirical observations of the form of this are made.</p>