scholarly journals Smouldering Combustion Dynamics of a Soil from a Pinus halepensis Mill. Forest. A Case Study of the Rocallaura Fires in Northeastern Spain

2020 ◽  
Vol 10 (10) ◽  
pp. 3449
Author(s):  
Miquel Àngel Xifré-Salvadó ◽  
Núria Prat-Guitart ◽  
Marcos Francos ◽  
Xavier Úbeda ◽  
Marc Castellnou
Keyword(s):  
Pinus Halepensis ◽  
Mineral Soil ◽  
Chemical Properties ◽  
Fire Regimes ◽  
Organic Soils ◽  
Ignition Probability ◽  
Combustion Dynamics ◽  
Wildfire Hazard ◽  
The Impact ◽  
Smouldering Combustion

This study analyses the smouldering combustion on soils that took place during the wildfires that occurred in Rocallaura (Northeastern Spain). The smouldering combustion after the first event, 23 June, was the potential source of flaming fire re-ignition of the second event, 19 July 2016. Re-ignitions are an important challenge for the firefighting system. Budget and efforts are spent on controlling these re-ignitions that can ultimately cause the collapse of the response system if the re-ignitions happen during periods of simultaneous fire events. Our objective is to contribute to better understand the dynamics of the smouldering combustion of organic soils associated with these wildfires and the impact on the Pinus halepensis Mill. forest ecosystem. Transects were established in adjacent control and post-fire zones. Laboratory analyses were conducted to determine some physical and chemical properties of both the duff and mineral soil. Using these variables, we estimate thresholds of duff ignition probability, percentage of duff consumption and smouldering combustion spread rates. Overall, we provide a set of tools for evaluating re-ignitions in forest ecosystems. We conclude that the concept of fire persistence should be a new variable for consideration in present and future analysis of fire regimes and demonstrates the significance of introducing smouldering combustion and re-ignition within the strategic framework of the wildfire hazard and integrating these phenomena into forest planning and management.

scholarly journals A new method for performing smouldering combustion field experiments in peatlands and rich-organic soils

2017 ◽  
Vol 26 (12) ◽  
pp. 1040 ◽  
Author(s):  
E. Pastor ◽  
I. Oliveras ◽  
E. Urquiaga-Flores ◽  
J. A. Quintano-Loayza ◽  
M. I. Manta ◽  
...  
Keyword(s):  
Field Experiments ◽  
Organic Soil ◽  
Ecological Effects ◽  
Organic Soils ◽  
Rating Systems ◽  
Environmental Implications ◽  
Combustion Dynamics ◽  
Peruvian Andes ◽  
Undisturbed Soils ◽  
Smouldering Combustion

Smouldering ground fires have severe environmental implications. Their main effects are the release of large amounts of carbon to the atmosphere with loses of organic soil and its biota. Quantitative data on the behaviour of smouldering wildfires are very scarce and are needed to understand its ecological effects, to validate fuel consumption and smouldering propagation models and to develop danger-rating systems. We present, for the first time, a methodology for conducting smouldering experiments in field conditions. This method provides key data to investigate smouldering combustion dynamics, acquire fire behaviour metrics and obtain indicators for ecological effects of smouldering fires. It is to be applied in all types of undisturbed soils. The experimental protocol is based on a non-electric ignition source and the monitoring system relies on combining both point and surface specific temperature measurements. The methodology has been developed and applied by means of large series of replicate experiments in highly organic soils at the forest–grassland treeline of the Peruvian Andes. The soil tested exhibited weak ignition conditions. However, transition to oxidation phase was observed, with smouldering combustion during 9 h at 15-cm depth and residence times at temperatures above dehydration of ~22 h.

The yield of perennial grass stands on drained organic soils of Steppe

2016 ◽  
Vol 1 (90) ◽  
pp. 92-97
Author(s):  
I.T. Slusar ◽  
V.A. Serbenyuk ◽  
A.N. Gera ◽  
A.P. Solyanik ◽  
A.A. Tarasenko
Keyword(s):  
Zinc Sulphate ◽  
Foliar Application ◽  
Perennial Grass ◽  
Mineral Fertilizer ◽  
Dry Weight ◽  
Research Area ◽  
Organic Soils ◽  
Growth Promoters ◽  
Cobalt Sulfate ◽  
The Impact

Research on the impact of the introduction of micro fertilizers and growth promoters on a background of mineral fertilizer and without N90R45К120 spent on old peat in shallow carbonate floodplain r.Supiy, Yahotyn Kyiv region. Power peat horizon about 60-70 cm, 7,4-7,6 pH of the aqueous extract, stupas schedule 56-60%, density 0,49-0,52 assembly soil, total nitrogen content (%) - 1.9; gross forms of phosphorus - 0,4, potassium 0.2, 20% lime. In experiments studying biological rehoplant, radustym, Biolan, emistim, Jets, humisol, plantafol, radyfarm and micronutrients: copper, boric acid, manganese sulphate, zinc sulphate, potassium humates. Treatment drugs conducted in the spring by spraying mixtures. Space research area of 60 m2, three-time repetition. It is established that the use of growth stimulants and micronutrients in the background N90R45К120 provided the highest yield mixtures of years, against making BIOLan - 9.9 t / ha Radyfarmu - 9.6 t / ha Radostymu 9.3 t / ha dry weight. In areas for making other preparations were intermediate yield growth rates - 0.5 - 2.0 t / ha dry weight. Also good gains herbage yields obtained by making all kinds of micronutrients and growth stimulants in the background without making makrodobryv which was within 5.3 - 6.9 t / ha to control without fertilization - 4.5 t / ha dry weight. In deep peat copper fertilizer (25 kg / ha of copper sulphate or 5 kg / ha pirytnoho cinders) in all zones should be making every 3-4 years, and zinc, cobalt and molybdenum advisable to make time for the growing season, spring, by foliar application in such numbers: ammonium molibdenovokyslyy - 0.3 kg / ha; cobalt sulfate - 3 kg / ha zinc sulphate 0.5 kg / ha or placers these salts should be mixed with major fertilizer.

scholarly journals The Impact of Filler Geometry on Polylactic Acid-Based Sustainable Polymer Composites

Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 149
Author(s):  
Karol Leluk ◽  
Stanisław Frąckowiak ◽  
Joanna Ludwiczak ◽  
Tomasz Rydzkowski ◽  
Vijay Kumar Thakur
Keyword(s):  
Polymer Composites ◽  
Polylactic Acid ◽  
Matrix Material ◽  
Chemical Properties ◽  
Precipitated Calcium Carbonate ◽  
Cellulose Fibres ◽  
Shape Factors ◽  
Pure Cellulose ◽  
Physico Chemical ◽  
The Impact

Recently, biocomposites have emerged as materials of great interest to the scientists and industry around the globe. Among various polymers, polylactic acid (PLA) is a popular matrix material with high potential for advanced applications. Various particulate materials and nanoparticles have been used as the filler in PLA based matrix. One of the extensively studied filler is cellulose. However, cellulose fibres, due to their hydrophilic nature, are difficult to blend with a hydrophobic polymer matrix. This leads to agglomeration and creates voids, reducing the mechanical strength of the resulting composite. Moreover, the role of the various forms of pure cellulose and its particle shape factors has not been analyzed in most of the current literature. Therefore, in this work, materials of various shapes and shape factors were selected as fillers for the production of polymer composites using Polylactic acid as a matrix to fill this knowledge gap. In particular, pure cellulose fibres (three types with different elongation coefficient) and two mineral nanocomponents: precipitated calcium carbonate and montmorillonite were used. The composites were prepared by a melt blending process using two different levels of fillers: 5% and 30%. Then, the analysis of their thermomechanical and physico-chemical properties was carried out. The obtained results were presented graphically and discussed in terms of their shape and degree of filling.

scholarly journals Understanding the Impact of Different Landscape-Level Fuel Management Strategies on Wildfire Hazard in Central Portugal

Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 522
Author(s):  
Akli Benali ◽  
Ana C. L. Sá ◽  
João Pinho ◽  
Paulo M. Fernandes ◽  
José M. C. Pereira
Keyword(s):  
Management Strategies ◽  
Treatment Strategies ◽  
Fire Season ◽  
Burned Area ◽  
Treatment Area ◽  
Fuel Treatment ◽  
The North ◽  
Wildfire Hazard ◽  
Central Portugal ◽  
The Impact

The extreme 2017 fire season in Portugal led to widespread recognition of the need for a paradigm shift in forest and wildfire management. We focused our study on Alvares, a parish in central Portugal located in a fire-prone area, which had 60% of its area burned in 2017. We evaluated how different fuel treatment strategies may reduce wildfire hazard in Alvares through (i) a fuel break network with different extents corresponding to different levels of priority and (ii) random fuel treatments resulting from a potential increase in stand-level management intensity. To assess this, we developed a stochastic wildfire simulation system (FUNC-SIM) that integrates uncertainties in fuel distribution over the landscape. If the landscape remains unchanged, Alvares will have large burn probabilities in the north, northeast and center-east areas of the parish that are very often associated with high fireline intensities. The different fuel treatment scenarios decreased burned area between 12.1–31.2%, resulting from 1–4.6% increases in the annual treatment area and reduced the likelihood of wildfires larger than 5000 ha by 10–40%. On average, simulated burned area decreased 0.22% per each ha treated, and cost-effectiveness decreased with increasing area treated. Overall, both fuel treatment strategies effectively reduced wildfire hazard and should be part of a larger, holistic and integrated plan to reduce the vulnerability of the Alvares parish to wildfires.

scholarly journals Assessment of Pellets from Three Forest Species: From Raw Material to End Use

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 447
Author(s):  
Miguel Alfonso Quiñones-Reveles ◽  
Víctor Manuel Ruiz-García ◽  
Sarai Ramos-Vargas ◽  
Benedicto Vargas-Larreta ◽  
Omar Masera-Cerutti ◽  
...  
Keyword(s):  
Chemical Properties ◽  
Ash Content ◽  
Hot Water ◽  
Raw Material ◽  
Chemical Components ◽  
Energy Yield ◽  
Cellulose Content ◽  
Fixed Carbon ◽  
End Use ◽  
The Impact

This study aimed to evaluate and compare the relationship between chemical properties, energy efficiency, and emissions of wood and pellets from madroño Arbutus xalapensis Kunth, tázcate Juniperus deppeana Steud, and encino colorado Quercus sideroxyla Humb. & Bonpl. in two gasifiers (top-lit-up-draft (T-LUD) and electricity generation wood camp stove (EGWCS)) in order to determine the reduction of footprint carbon. In accordance with conventional methodologies, we determined the extracts and chemical components (lignin, cellulose, holocellulose), and the immediate analyses were carried out (volatile materials, fixed carbon, ash content and microanalysis of said ash), as well as the evaluation of emission factors (total suspended particulate matter (PM2.5), CO, CO2, CH4, black carbon (BC), elemental carbon (EC), and organic carbon (OC)). The results were statistically analyzed to compare each variable among species and gasifiers. The raw material analyzed showed how the pH ranged from 5.01 to 5.57, and the ash content ranged between 0.39 and 0.53%. The content values of Cu, Zn, Fe, Mg, and Ca ranged from 0.08 to 0.22, 0.18 to 0.19, 0.38 to 0.84, 1.75 to 1.90, and 3.62 to 3.74 mg kg−1, respectively. The extractive ranges from cyclohexane were 2.48–4.79%, acetone 2.42–4.08%, methanol 3.17–7.99%, and hot water 2.12–4.83%. The range of lignin was 18.08–28.60%. The cellulose content ranged from 43.30 to 53.90%, and holocellulose from 53.50 to 64.02%. The volatile material range was 81.2–87.42%, while fixed carbon was 11.30–17.48%; the higher heating value (HHV) of raw material and pellets presented the ranges 17.68–20.21 and 19.72–21.81 MJ kg−1, respectively. Thermal efficiency showed statistically significant differences (p < 0.05) between pellets and gasifiers, with an average of 31% Tier 3 in ISO (International Organization for Standardization) for the T-LUD and 14% (ISO Tier 1) for EGWCS, with Arbutus xalapensis being the species with the highest energy yield. The use of improved combustion devices, as well as that of selected raw material species, can reduce the impact of global warming by up to 33% on a cooking task compared to the three-stone burner.

scholarly journals Stiffness and Strength of Stabilized Organic Soils—Part I/II: Experimental Database and Statistical Description for Machine Learning Modelling

Geosciences ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 243
Author(s):  
Hernandez-Martinez Francisco G. ◽  
Al-Tabbaa Abir ◽  
Medina-Cetina Zenon ◽  
Yousefpour Negin
Keyword(s):  
Machine Learning ◽  
Statistical Analysis ◽  
Portland Cement ◽  
Soil Stabilization ◽  
Data Availability ◽  
Data Repository ◽  
Organic Soils ◽  
Experimental Database ◽  
Soil Mixing ◽  
The Impact

This paper presents the experimental database and corresponding statistical analysis (Part I), which serves as a basis to perform the corresponding parametric analysis and machine learning modelling (Part II) of a comprehensive study on organic soil strength and stiffness, stabilized via the wet soil mixing method. The experimental database includes unconfined compression tests performed under laboratory-controlled conditions to investigate the impact of soil type, the soil’s organic content, the soil’s initial natural water content, binder type, binder quantity, grout to soil ratio, water to binder ratio, curing time, temperature, curing relative humidity and carbon dioxide content on the stabilized organic specimens’ stiffness and strength. A descriptive statistical analysis complements the description of the experimental database, along with a qualitative study on the stabilization hydration process via scanning electron microscopy images. Results confirmed findings on the use of Portland cement alone and a mix of Portland cement with ground granulated blast furnace slag as suitable binders for soil stabilization. Findings on mixes including lime and magnesium oxide cements demonstrated minimal stabilization. Specimen size affected stiffness, but not the strength for mixes of peat and Portland cement. The experimental database, along with all produced data analyses, are available at the Texas Data Repository as indicated in the Data Availability Statement below, to allow for data reproducibility and promote the use of artificial intelligence and machine learning competing modelling techniques as the ones presented in Part II of this paper.

scholarly journals The impact of orally administered gadolinium orthovanadate GdVO4:Eu3+ nanoparticles on the state of phospholipid bilayer of erythrocytes

2020 ◽  
Vol 45 (4) ◽  
pp. 389-395
Author(s):  
Anton Tkachenko ◽  
Anatolii Onishchenko ◽  
Vladimir Klochkov ◽  
Nataliya Kavok ◽  
Oksana Nakonechna ◽  
...  
Keyword(s):  
Fluorescent Probes ◽  
Lipid Membranes ◽  
Chemical Properties ◽  
Proton Donor ◽  
The State ◽  
Phospholipid Bilayer ◽  
Erythrocyte Membranes ◽  
Control Group ◽  
Donor Ability ◽  
The Impact

AbstractObjectivesTo assess the state of phospholipid bilayer of red blood cells (RBCs) in rats orally exposed to gadolinium orthovanadate GdVO4:Eu3+ nanoparticles (VNPs) during two weeks using fluorescent probes − ortho-hydroxy derivatives of 2,5-diaryl-1,3-oxazole.MethodsSteady-state fluorescence spectroscopy: a study by the environment-sensitive fluorescent probes − 2-(2′-OH-phenyl)-5-phenyl-1,3-oxazole (probe O1O) and 2-(2′-OH-phenyl)-phenanthro[9,10]-1,3-oxazole (probe PH7).ResultsNo significant changes are detected in the spectra of the fluorescent probes bound to the RBCs from the rats orally exposed to nanoparticles in comparison with the corresponding spectra of the probes bound to the cells from the control group of animals. This indicates that, in case of the rats orally exposed to nanoparticles, no noticeable changes in physico-chemical properties (i.e., in the polarity and the proton-donor ability) are observed in the lipid membranes of RBCs in the region, where the probes locate.ConclusionsNo changes in the physical and chemical properties of the erythrocyte membranes are detected in the region from glycerol backbones of phospholipids to the center of the phospholipid bilayer in the rats orally exposed to VNPs during 2 weeks.

scholarly journals Response of simulated burned area to historical changes in environmental and anthropogenic factors: a comparison of seven fire models

2019 ◽  
Vol 16 (19) ◽  
pp. 3883-3910 ◽  
Author(s):  
Lina Teckentrup ◽  
Sandy P. Harrison ◽  
Stijn Hantson ◽  
Angelika Heil ◽  
Joe R. Melton ◽  
...  
Keyword(s):  
Land Use ◽  
Co2 Concentration ◽  
Fire Regimes ◽  
Atmospheric Co2 ◽  
Anthropogenic Factors ◽  
Burned Area ◽  
Earth System ◽  
Atmospheric Co2 Concentration ◽  
Fire Models ◽  
The Impact

Abstract. Understanding how fire regimes change over time is of major importance for understanding their future impact on the Earth system, including society. Large differences in simulated burned area between fire models show that there is substantial uncertainty associated with modelling global change impacts on fire regimes. We draw here on sensitivity simulations made by seven global dynamic vegetation models participating in the Fire Model Intercomparison Project (FireMIP) to understand how differences in models translate into differences in fire regime projections. The sensitivity experiments isolate the impact of the individual drivers on simulated burned area, which are prescribed in the simulations. Specifically these drivers are atmospheric CO2 concentration, population density, land-use change, lightning and climate. The seven models capture spatial patterns in burned area. However, they show considerable differences in the burned area trends since 1921. We analyse the trajectories of differences between the sensitivity and reference simulation to improve our understanding of what drives the global trends in burned area. Where it is possible, we link the inter-model differences to model assumptions. Overall, these analyses reveal that the largest uncertainties in simulating global historical burned area are related to the representation of anthropogenic ignitions and suppression and effects of land use on vegetation and fire. In line with previous studies this highlights the need to improve our understanding and model representation of the relationship between human activities and fire to improve our abilities to model fire within Earth system model applications. Only two models show a strong response to atmospheric CO2 concentration. The effects of changes in atmospheric CO2 concentration on fire are complex and quantitative information of how fuel loads and how flammability changes due to this factor is missing. The response to lightning on global scale is low. The response of burned area to climate is spatially heterogeneous and has a strong inter-annual variation. Climate is therefore likely more important than the other factors for short-term variations and extremes in burned area. This study provides a basis to understand the uncertainties in global fire modelling. Both improvements in process understanding and observational constraints reduce uncertainties in modelling burned area trends.

scholarly journals Impact of Carcinogenic Chromium on the Cellular Response to Proteotoxic Stress

2019 ◽  
Vol 20 (19) ◽  
pp. 4901 ◽  
Author(s):  
Leonardo M. R. Ferreira ◽  
Teresa Cunha-Oliveira ◽  
Margarida C. Sobral ◽  
Patrícia L. Abreu ◽  
Maria Carmen Alpoim ◽  
...  
Keyword(s):  
Stress Response ◽  
Health Effects ◽  
Cellular Response ◽  
Molecular Mechanisms ◽  
Critical Role ◽  
Chemical Properties ◽  
Adverse Health Effects ◽  
Proteotoxic Stress ◽  
Adverse Health ◽  
The Impact

Worldwide, several million workers are employed in the various chromium (Cr) industries. These workers may suffer from a variety of adverse health effects produced by dusts, mists and fumes containing Cr in the hexavalent oxidation state, Cr(VI). Of major importance, occupational exposure to Cr(VI) compounds has been firmly associated with the development of lung cancer. Counterintuitively, Cr(VI) is mostly unreactive towards most biomolecules, including nucleic acids. However, its intracellular reduction produces several species that react extensively with biomolecules. The diversity and chemical versatility of these species add great complexity to the study of the molecular mechanisms underlying Cr(VI) toxicity and carcinogenicity. As a consequence, these mechanisms are still poorly understood, in spite of intensive research efforts. Here, we discuss the impact of Cr(VI) on the stress response—an intricate cellular system against proteotoxic stress which is increasingly viewed as playing a critical role in carcinogenesis. This discussion is preceded by information regarding applications, chemical properties and adverse health effects of Cr(VI). A summary of our current understanding of cancer initiation, promotion and progression is also provided, followed by a brief description of the stress response and its links to cancer and by an overview of potential molecular mechanisms of Cr(VI) carcinogenicity.

scholarly journals Treated wastewater irrigation effects on soil hydraulic conductivity and aggregate stability of loamy soils in Israel

2015 ◽  
Vol 63 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Karsten Schacht ◽  
Bernd Marschner
Keyword(s):  
Hydraulic Conductivity ◽  
Chemical Properties ◽  
Aggregate Stability ◽  
Treated Wastewater ◽  
Soil Aggregate Stability ◽  
Irrigation Effects ◽  
Physical And Chemical ◽  
The Impact

Abstract The use of treated wastewater (TWW) for agricultural irrigation becomes increasingly important in water stressed regions like the Middle East for substituting fresh water (FW) resources. Due to elevated salt concentrations and organic compounds in TWW this practice has potential adverse effects on soil quality, such as the reduction of hydraulic conductivity (HC) and soil aggregate stability (SAS). To assess the impact of TWW irrigation in comparison to FW irrigation on HC, in-situ infiltration measurements using mini disk infiltrometer were deployed in four different long-term experimental orchard test sites in Israel. Topsoil samples (0-10 cm) were collected for analyzing SAS and determination of selected soil chemical and physical characteristics. The mean HC values decreased at all TWW sites by 42.9% up to 50.8% compared to FW sites. The SAS was 11.3% to 32.4% lower at all TWW sites. Soil electrical conductivity (EC) and exchangeable sodium percentage (ESP) were generally higher at TWW sites. These results indicate the use of TWW for irrigation is a viable, but potentially deleterious option, as it influences soil physical and chemical properties.

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