scholarly journals Geotechnical Characterization of Biochar-Based Biocover

2020 ◽  
Vol 5 (4) ◽  
pp. 77-87
Author(s):  
Taiwo, Ridwan Ademola ◽  
Adegoke Adesola Habeeb ◽  
Mojeed Mutiu Ayobami
Keyword(s):  
Biochemical Properties ◽  
Unit Weight ◽  
Ch4 Emission ◽  
Microbial Oxidation ◽  
Landfill Cover Soil ◽  
Landfill Cover ◽  
Dry Unit Weight ◽  
Geotechnical Characterization ◽  
Two Samples

Landfills are one of the major sources of methane (CH4) emission which is a very potent greenhouse gas. The use of a natural process for microbial CH4 oxidation through biocovers provides a source reduction of CH4 emission. Previous studies have mostly focused on biochemical properties, and limited research has been conducted with regards to the geotechnical characterization of biochar based biocovers. This paper presents the results of a comprehensive laboratory investigation on laterite, Igbokoda sand and their mixtures with biochar at 2%, 4%, 8%, 10% and 20% to determine the compaction properties of biochar based biocovers. From the result, it was shown that the laterite has medium plasticity while the Igbokoda sand is non-plastic. Also, Addition of biochar to landfill cover soil increased the particle sizes, and consequently the porosity of the soil is increased which can promote the air flow through the landfill cover. Thus, greater O2 diffusion within the landfill cover will result, leading to higher microbial oxidation/degradation of CH4. Maximum dry unit weight decreased and the optimum water content partly increased as the biochar content increased with the two samples. Compaction test results show that when biochar content varied from 0 to 20% for the laterite, the maximum dry unit weight decreased from 1660kg/m3 to 1330kg/m3 and decreased from 1590kg/m3 to 1390kg/m3 for Igbokoda Sand. Thus, the results presented in this paper will contribute to a better understanding of the geotechnical behaviour of biochar based biocover.

scholarly journals Evaluations of the effects of soil properties and electrical conductivity on the water content reflectometer calibration for landfill cover soils

2017 ◽  
Vol 12 (No. 1) ◽  
pp. 10-17 ◽  
Author(s):  
K. Kim ◽  
J. Sim ◽  
T.-H. Kim
Keyword(s):  
Electrical Conductivity ◽  
Soil Properties ◽  
Water Content ◽  
Clay Content ◽  
Liquid Limit ◽  
Time Domain Reflectometry ◽  
Volumetric Water Content ◽  
Unit Weight ◽  
Landfill Cover ◽  
Dry Unit Weight

This study presents soil-moisture calibrations using low-frequency (15–40 MHz) time domain reflectometry (TDR) probe, referred to as water content reflectometer (WCR), for measuring the volumetric water content of landfill cover soils, developing calibrations for 28 different soils, and evaluating how WCR calibrations are affected by soil properties and electrical conductivity. A 150-mm-diameter PVC cell was used for the initial WCR calibration. Linear and polynomial calibrations were developed for each soil. Although the correlation coefficients (R<sup>2</sup>) for the polynomial calibration are slightly higher, the linear calibrations are accurate and pragmatic to use. The effects of soil electrical conductivity and index properties were investigated using the slopes of linear WCR calibrations. Soils with higher electrical conductivity had lower calibration slopes due to greater attenuation of the signal during transmission in the soil. Soils with higher electrical conductivity tended to have higher clay content, organic matter, liquid limit, and plasticity index. The effects of temperature and dry unit weight on WCR calibrations were assessed in clayey and silty soils. The sensor period was found to increase with the temperature and density increase, with greater sensitivity in fine-textured plastic soils. For typical variations in temperature, errors in volumetric water content on the order of 0.04 can be expected for wet soils and 0.01 for drier soils if temperature corrections are not applied. Errors on the order of 0.03 (clays) and 0.01 (silts) can be expected for typical variations in dry unit weight (± 2 kN/m<sup>3</sup>).

scholarly journals Characterization of weathering profiles of the crystal rocks of eastern Bucaramanga and definition of hydrogeological properties

2017 ◽  
pp. 16-30
Author(s):  
Juan Diego Colegial-Gutiérrez ◽  
María Camila Forero-Quintero ◽  
María Alejandra Fuentes-Rueda ◽  
Sully Gomez Isidro
Keyword(s):  
Chemical Weathering ◽  
Unit Weight ◽  
X Ray ◽  
Weathered Rock ◽  
Weathering Processes ◽  
Dry Unit Weight ◽  
Physico Chemical ◽  
Hydrogeological Properties ◽  
Definition Of

In the process of improving the knowledge of the hydrogeological potential of weathered zones in crystalline rocks and compounds that can behave as aquifers, this article is performed whose area of study is located east of the metropolitan area of Bucaramanga, Santander Massif consists of two main lithological units; the Neis of Bucaramanga and Santander Group plutonic (diorite, granodiorite-tonalite gray quartz monzonite and monzogranite). These rocks have undergone brittle deformation, physico-chemical weathering mainly influenced by the tropical atmosphere of the area also are jointed and fractured creating conditions that facilitate the flow of water and in turn be optimized weathering processes in the region. He appealed to the identification and location of field weathering profiles made a detailed study of outcrops, presenting a thickness of 90.4 m for the profile of the Gneisic rock weathering and 68.5 m for the profile of granodiorite rock, made up 6 steps weathering of which samples each were taken and carry out macroscopic analysis, petrographic and geochemical using thin films, determining the percentage of porosity, humidity, dry unit weight, X-ray fluorescence, electron microscopy Sweeping and Grading; base characterizing weathering profiles and properties, highlighting the potential hydrogeological found in the Range II: Slightly weathered rock and interval V: Completely weathered rock profile of granodiorite rock and Rock Gneisic profile, the interval III : Moderately weathered rock and the range V: Completely weathered rock, since these stages of weathering, moisture peaks present, regular micro fractures and high porosities.

scholarly journals Microbial oxidation of CH4 at high partial pressures in an organic landfill cover soil under different moisture regimes

1998 ◽  
Vol 26 (3) ◽  
pp. 207-217 ◽  
Author(s):  
Gunnar Börjesson ◽  
Ingvar Sundh ◽  
Anders Tunlid ◽  
Ã…Sa FrostegÃ¥rd ◽  
Bo H Svensson
Keyword(s):  
Microbial Oxidation ◽  
Landfill Cover Soil ◽  
Landfill Cover ◽  
Cover Soil ◽  
Partial Pressures ◽  
Moisture Regimes

Application of commercial test-systems to identify gram-negative facultatively anaerobic bacteria

2016 ◽  
Vol 3 (1) ◽  
pp. 43-48 ◽  
Author(s):  
V. Patyka ◽  
L. Butsenko ◽  
L. Pasichnyk
Keyword(s):  
Erwinia Amylovora ◽  
Anaerobic Bacteria ◽  
Biochemical Properties ◽  
Test System ◽  
Phytopathogenic Bacteria ◽  
Gram Negative ◽  
Test Systems ◽  
Facultatively Anaerobic ◽  
Microbiological Methods

Aim. To validate the suitability of commercial API 20E test-system (bioMerieux) for the identifi cation and characterization of facultative gram-negative phytopathogenic bacterial isolates. Methods. Conventional mi- crobiological methods, API 20E test-system (bioMerieux) according to the manufacturer’s instructions. Re- sults. The identifi cation results for Erwinia amylovora, Pectobacterium carotovorum and Pantoea agglome- rans isolates were derived from the conventional and API 20E test systems, which, were in line with the literature data for these species. The API 20E test-system showed high suitability for P. agglomerans isolates identifi cation. Although not all the species of facultatively anaerobic phytopathogenic bacteria may be identi- fi ed using API 20E test-system, its application will surely allow obtaining reliable data about their physiologi- cal and biochemical properties, valuable for identifi cation of bacteria, in the course of 24 h. Conclusions. The results of tests, obtained for investigated species while using API 20E test-system, and those of conventional microbiological methods coincided. The application of API 20E test-system (bioMerieux) ensures fast obtain- ing of important data, which may be used to identify phytopathogenic bacteria of Erwinia, Pectobacterium, Pantoea genera.

scholarly journals Biochemical characterization of specific Alanine Decarboxylase (AlaDC) and its ancestral enzyme Serine Decarboxylase (SDC) in tea plants (Camellia sinensis)

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Peixian Bai ◽  
Liyuan Wang ◽  
Kang Wei ◽  
Li Ruan ◽  
Liyun Wu ◽  
...  
Keyword(s):  
Gene Duplication ◽  
Camellia Sinensis ◽  
Biochemical Characterization ◽  
Specific Activity ◽  
Protein Sequences ◽  
Biochemical Properties ◽  
High Similarity ◽  
New Gene ◽  
Tea Plants

Abstract Background Alanine decarboxylase (AlaDC), specifically present in tea plants, is crucial for theanine biosynthesis. Serine decarboxylase (SDC), found in many plants, is a protein most closely related to AlaDC. To investigate whether the new gene AlaDC originate from gene SDC and to determine the biochemical properties of the two proteins from Camellia sinensis, the sequences of CsAlaDC and CsSDC were analyzed and the two proteins were over-expressed, purified, and characterized. Results The results showed that exon-intron structures of AlaDC and SDC were quite similar and the protein sequences, encoded by the two genes, shared a high similarity of 85.1%, revealing that new gene AlaDC originated from SDC by gene duplication. CsAlaDC and CsSDC catalyzed the decarboxylation of alanine and serine, respectively. CsAlaDC and CsSDC exhibited the optimal activities at 45 °C (pH 8.0) and 40 °C (pH 7.0), respectively. CsAlaDC was stable under 30 °C (pH 7.0) and CsSDC was stable under 40 °C (pH 6.0–8.0). The activities of the two enzymes were greatly enhanced by the presence of pyridoxal-5′-phosphate. The specific activity of CsSDC (30,488 IU/mg) was 8.8-fold higher than that of CsAlaDC (3467 IU/mg). Conclusions Comparing to CsAlaDC, its ancestral enzyme CsSDC exhibited a higher specific activity and a better thermal and pH stability, indicating that CsSDC acquired the optimized function after a longer evolutionary period. The biochemical properties of CsAlaDC might offer reference for theanine industrial production.

scholarly journals Plasticity in Neuroblastoma Cell Identity Defines a Noradrenergic-to-Mesenchymal Transition (NMT)

Cancers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2904
Author(s):  
Margot Gautier ◽  
Cécile Thirant ◽  
Olivier Delattre ◽  
Isabelle Janoueix-Lerosey
Keyword(s):  
Epithelial To Mesenchymal Transition ◽  
Neuroblastoma Cell ◽  
Neuroblastoma Cells ◽  
Biochemical Properties ◽  
Poor Overall Survival ◽  
Cell Identity ◽  
Mesenchymal Transition ◽  
Neuroblastoma Cell Lines

Neuroblastoma, a pediatric cancer of the peripheral sympathetic nervous system, is characterized by an important clinical heterogeneity, and high-risk tumors are associated with a poor overall survival. Neuroblastoma cells may present with diverse morphological and biochemical properties in vitro, and seminal observations suggested that interconversion between two phenotypes called N-type and S-type may occur. In 2017, two main studies provided novel insights into these subtypes through the characterization of the transcriptomic and epigenetic landscapes of a panel of neuroblastoma cell lines. In this review, we focus on the available data that define neuroblastoma cell identity and propose to use the term noradrenergic (NOR) and mesenchymal (MES) to refer to these identities. We also address the question of transdifferentiation between both states and suggest that the plasticity between the NOR identity and the MES identity defines a noradrenergic-to-mesenchymal transition, reminiscent of but different from the well-established epithelial-to-mesenchymal transition.

Sign in / Sign up

Export Citation Format

Share Document