Size Of Fines Research Articles

Regulatory or market pressures: What promotes environmental grandstanding in Bangladesh?

Many factors affect the adoption of the mandatory technology of effluent treatment plants for pollution management in Bangladesh. Some of these factors could also affect the adoption of voluntary environmental standards. Therefore, it is important to identify and analyze the importance of these key factors, considering their role in enhancing environmental performance in crucial industries for the country's economy. In this study, a literature review preceded an analysis of factors through structural equation modelling to investigate how attributes of the regulatory agency combine with market aspects to influence environmental practices such as the adoption of mandatory ETP and voluntary certifications. Using official quarterly data, the results of this study show that access to green finance and the number of employees of the regulatory agency significantly affect the adoption of additional ETPs. On the other hand, the size of fines for pollution does not significantly affect the adoption of ETPs. It was also found that green finance and additional ETP adoption also increased the adoption of green factory buildings, which is a voluntary exercise. This study sheds light on the underlying relationships that can guide ongoing multilateral interventions to enhance capacity of regulatory agencies to implement environmental regulations. It also provides new evidence to formulate relevant strategies for enhancing environmental performance by scaling up green finance.

Investigation of an effective acid pre-treatment method for the valorisation of Canola fines

Canola fines are the straw-like material and other residues removed from incoming Canola crops before processing for seed oil. In South Africa, this lignocellulosic biomass is abundant and non-seasonal, making it an ideal substrate for recovery of sugars for valorization to higher value products. Pre-treatment for release of sugars from lignocellulose should be optimized for a given substrate. In this study, mechanical pre-treatment to reduce the size of Canola fines was followed by: (i) steam-assisted acid pre-treatment (0–2% H2SO4 % v/v) at different temperatures (20–55 °C), and biomass loading rates (2–8% w/v), and (ii) enzyme hydrolysis, using a central composite experimental design approach. The sugars in the hydrolysates obtained from stages (i) and (ii) were measured quantitatively and qualitatively as outputs that were used to assess process efficiency and to obtain predictive models. The raw and spent Canola fines from each phase were fully characterized in terms of chemical and structural changes at each stage of pre-treatment.The Canola fines contained 23.0% w/w lignin, 21.4% w/w cellulose, and 15.9% w/w hemicellulose. The maximum yield of total sugars after steam-assisted acid hydrolysis (18.6% w/w) was increased after enzyme hydrolysis (28.3 % w/w) and was higher than reported for other studies pre-treating rapeseed and Canola straws (10.2–11.8% w/w). The sugar profiles in the hydrolysates after steam-assisted acid hydrolysis (xylose>arabinose>glucose) differed from those obtained after acid-assisted enzyme hydrolysis (xylose>glucose>cellobiose>arabinose). The microscopic and chemical analyses of the Canola fines showed sequential breakdown of the lignin, cellulose, and hemicellulose, with some lignin still intact at the end of the pre-treatment. For application of this technology, no heating would be required for acid pre-treatment as temperature was not a significant variable. In addition, the optimal H2SO4 concentration was low (1.7% v/v), minimizing the use of hazardous chemicals as well as the risk of releasing microbial and/or enzyme inhibitors during the process. Enzyme hydrolysis should only be required if the downstream application requires higher sugar concentrations and/or different sugar profiles.

ДЕКРИМИНАЛИЗАЦИЯ УГОЛОВНОЙ ОТВЕТСТВЕННОСТИ ЗА ОСКОРБЛЕНИЕ ЛИЧНОСТИ: ТРЕБУЕТСЯ НЕ ЛИБЕРАЛИЗАЦИЯ, А МОДЕРНИЗАЦИЯ ЗАКОНОДАТЕЛЬСТВА

The article is devoted to the study of the problems of law enforcement practice on the application of administrative responsibility for insulting a person. The current legislation divides these offenses by special compositions into criminal offenses and general ones into administrative offenses. The article analyzes statistical data and examples of law enforcement activities, which indicate the priority right to protect victims with special statuses, in particular, representatives of state authorities. It has been substantiated that today it is necessary to take the following measures of a legal and organizational nature: to provide for criminal liability for insult in case of repeated commission of an offense by a person subjected to administrative punishment for a similar offense within a year; to legislate the definition of «indecent form» of insult; take into account another form that is humiliating and offending to public morality; to establish normatively the criteria for assessing the offensiveness of words, expressions and actions; consider the possibility of introducing the punishment of administrative arrest; significantly toughen sanctions by increasing the size of fines.

MIĘDZY PREWENCYJNYM A BEZPRAWNYM POZBAWIENIEM WOLNOŚCI − UWAGI NA TLE INSTYTUCJI KWARANTANNY

This article attempts to provide a partial examination of the title issue in the Polish legal order from the point of view of criminal law. The basic thesis of the article boils down to the statement that the criminal law limits of admissibility of the application of quarantine in Poland, during the Covid-19 pandemic, contradicted, inter alia, article 5(1)(e) of the ECHR, but also violated the accepted order of hierarchy of Polish legal acts as referred to in the Constitution and the rules of correct legislation. In order to demonstrate such a statement, the manner and conditions and the possibility of applying this type of measure of medical coercion, as well as the sanctions for its violation, were taken into account. Attention was paid to selected consequences resulting from this classification. In addition, a survey of the case law of the common courts, administrative courts, the Supreme Court and the Supreme Administrative Court on the violation of quarantine was carried out. It has been assumed that the court’s imputation of a criminal act the elements of which are defined by a blanket provision of the criminal act and supplementary provisions of other normative acts, requires: 1) verifying the admissibility of regulating a specific matter with regulations of a sub-statutory rank; 2) examining the compliance with the Constitution of the content of such regulations are in line with the blanket regulation, and 3) observing the scope of the authorization to issue them, placed in the law. The aforementioned matters must be regulated directly in the law, which will ensure that the standards resulting from the Constitution are met, and their enforcement should be carried out by sanitary authorities or courts. The view was expressed that in criminal procedure, preventive measures should be aimed at the prevention of crimes and not at every unlawful act. It was stressed that the public authorities should take responsibility for every unlawful violation of constitutionally protected rights. It was argued that the size of any administrative fines imposed for noncompliance with the quarantine obligation should be proportionate to the financial capacity of the majority of citizens, in accordance with the directives that follow from administrative law. Finally, a critical assessment was made of the legality of imposing quarantine in the context of international treaty obligations for the protection of human rights.

Effect of Return Fines Embedding on the Sintering Behaviour of Vanadium Titanium Magnetite Concentrates

To improve the permeability of sinter packed bed for achieving the efficient utilization of low-grade iron bearing minerals, the effect of the returned fines embedding on productivity, yield, flame front speed (FFS) in the vanadium titanium magnetite (VTM) sintering process, tumble index (TI) of sinter, and permeability of the sinter packed bed was clarified. Results indicate that the productivity, yield, flame front speed, and tumble index of the vanadium titanium magnetite sintering process are all increased to a certain extent after embedding different sizes of returned fines, and the optimal sintering indices occur when the particle size of return fines for embedding is 3~5 mm. The optimal mass ratio of return fines for embedding was confirmed at 80%, and a continued increase in the mass ratio results in a decrease in flame front speed, yield, productivity, and tumble strength. Among the five different possible locations of embedded return fine layer, the middle-lower layer corresponds to the highest flame front speed. As the mass ratio of return fines for embedding is enhanced from 0% to 50%, the permeability of the sinter packed bed is improved at each stage of sintering.

Relationship of particle size, reaction and sticking behavior of iron ore fines toward efficient fluidized bed reduction

The relationship of particle size, reaction and sticking behavior of iron ore fines toward efficient fluidized bed hydrogen reduction were systematically investigated at 600–800 °C in a laboratory fluidized bed. First, the reduction kinetics were studied, and the results showed that hydrogen reduction of granulated iron ore was controlled by reduction reaction, and the activation energy was approximately 88.4 kJ/mol. The reduction rate of granulated iron ore with a diameter of 200 μm could be increased by 10 times as the reduction temperature rose from 600 to 800 °C. Then, a modified force balance model was established to distinguish the critical sticking point of granulated iron ore during high temperature fluidized bed hydrogen reduction, and it indicated that the defluidization temperature could be raised from 630 to 790 °C as the particle size was enlarged from 100 to 200 μm with a fluidization number of 10. Eventually, coupling the kinetic model and modified force balance model, the maximum gas utilization rate of fluidized bed hydrogen reduction was estimated, and it indicated that at reduction temperatures of 650–750 °C with particle sizes of 200–300 μm, the optimal gas utilization rate could be achieved, which was consistent with the experimental results. Contradictory to traditional understandings of chemical reaction engineering, due to the interaction of reduction performance and sticking behavior, too high of a reduction temperature or too small of a particle size might not be preferable for fluidized bed hydrogen reduction, and this study provided valuable references for industrial operation.

Administrative sanctions for anti-trust violations: interpretation issues

The legal definition of anti-competitive offenses and the size of fines imposed for their commission are fully consistent with the best international standards and foreign practices. However, in order to further increase the effec-tiveness of application of competition law through its proper interpretation, it should be assumed that the provisions of competition law on sanctions for its violation are inextricably linked with the objectives of competition law, which means that each sanction should be aimed at supporting and protection of economic competition, restriction of monopoly in economic activity to ensure the effective functioning of the economy of Ukraine on the basis of the development of unrestrained competition, which excludes taking into account when deciding on the guilt of the business entity for anticompetitive actions, protection of the national producer and interests of consumers if it is out of connection with fairness of competition. Also, to improve the interpretation of the rule of law in context of the 
 requirement of proportionality of sanctions for anti-trust violations, we note that in exceptional circumstances, the application of competition law, businesses should not lose the opportunity to conduct business and compete prop-erly on fair terms, which determines the need to interpret competition law in context of fines for anticompetitive offenses so that the impact of fines on the financial condition and solvency of economic entities does not irreversibly undermine their business activities with their actual withdrawal from the market. For instance, structural remedies, such as a forced separation of business entity holding a dominant position in the market, are subject to a stricter pro-portionality requirement as they can only be imposed either where there is no equally effective behavioural remedy or where any equally effective behavioural remedy would be more burdensome for the undertaking concerned than the structural remedy.

Pore-scale simulation of fine particles migration in porous media using coupled CFD-DEM

Transport of fine particles in porous media has attracted a considerable interest over the past several decades given its importance to many industrial and natural processes. In order to control fine particles transport in porous media, the behavior itself needs to be predicted and analyzed. Which could be quite costly to do in a laboratory experiment, hence the modelling of such a behavior would be an optimum way to study. In this work, we present a coupled computational fluid dynamics-discrete element method (CFD-DEM) based modelling framework that is capable of simulating the migration of a large number of fine particles, on the colloids size through physically realistic porous media. The model was parallelized using Message Passing Interface (MPI) protocol to resolve particle-particle and particle-grain interactions for a large number of fine particles. The model's geometry was generated from computed tomography images of sand packs, the CFD solver were set to solve the fluid flow while the DEM were to solve the particles physical interactions. Immersed Boundary Method (IBM) were used to couple the two solvers in a resolved manner. The model's setup was first validated to capture single phase fluid flow behavior and then the coupling of the fluid flow and particle interaction was compared to experimental results. In order to validate the coupled CFD-DEM model, velocity profiles of fine particles, their diffusion in the pore space and the percentage of fine particles retained in the pore space obtained from micromodel experiment were compared to values obtained from simulations using the same pore space geometry and initial experimental conditions. The presented framework was shown to capture the bulk dynamics of fine particulate transport and deposition within geologically realistic and complex flow domains while minimizing execution time.The model was used to study the impact of flow velocity and size of fines on permeability reduction of porous media due to migration of fine particles. Simulations indicate that permeability reduction due to fine migration in porous media is directly proportional to flow velocity. The time required to develop bridging and subsequent clogging of the pore space that lead to permeability reduction decreases as the flow velocity increases. The size of the fine particles has a significant impact on permeability reduction where the reduction in permeability increases as the size of particles increases. A faster and larger reduction in permeability was observed when a suspension of polydisperse particles was injected as opposed to a monodisperse suspension.

Does the monetary cost of abstaining increase turnout? Causal evidence from Peru

We study the elasticity of turnout on the size of the monetary fines that governments impose on those who fail to vote. We leverage a discontinuity in the size of monetary fines in Peru, where voters in districts above an arbitrary cutoff in poverty rates face higher fines for not voting relative to voters who reside in districts below the cutoff. Using individual-level data on millions of voters for every regional and national election between 2010 and 2016, we find that turnout increases slightly in districts with higher fines—an effect of roughly one percent. This modest effect is similar across socioeconomic groups and elections. Our results highlight a challenge that governments face in designing the sanctions in compulsory voting systems: how to increase turnout without disproportionally hurting the poor or raising turnout inequality.

Nanoparticle de-agglomeration in viscous fluids using different high shear mixer geometries

In the present work, the effect of batch high shear mixer (HSM) geometries is studied on nanoparticles deagglomeration and power draw in water and aqueous glycerol solutions. The kinetics and mechanism of cluster break-up are investigated for disintegrated (less number of larger stator holes), and mesh (higher number of smaller stator holes) heads at different rotor speeds. Mesh head geometry is found to be more efficient for fines generation than disintegrated head. A bi-modal particle size distribution and erosion as dominant break-up mechanism is found. The size of the smallest fines is found to be ≈30 nm for mesh head and ≈50 nm for the disintegrated head. Z-average ranges from 180 to 310 nm for given operating and process conditions. The power draw is more in mesh head and increased with an increase in viscosity. Further, power draw increased with an increase in viscosity of continuous media and rotor speed.

Environmental and economic model for sustainable development of a region (the case of Samara Oblast)

Biodiversity in natural ecosystems, with the increasing anthropogenic transformation of the environment, is becoming an increasingly important direction of research every decade. We propose to consider the number of game animals as one of the indicators of biodiversity. Since they are the most steadily observed objects in specially protected and anthropogenically transformed territories. Biodiversity conservation ensures sustainable development. In this regard, using the example of Samara Oblast, we considered the principles of biodiversity conservation in environmental and economic systems, including anthropogenically modified and specially protected natural areas, in order to ensure sustainable development at the regional level. We selected some ecological and economic spatially distributed characteristics of the environmental-economic system and compiled equations of multiple linear regression of the dependence of the number of game animals on the factors that have the greatest influence. These are the following factors: the volume of industrial production, investments in fixed assets, the value of fixed assets of industry, payments for natural resources, fines for violation of legislation in the use of natural resources, species diversity of animals, generalized assessment of atmospheric air pollution, percentage of forest cover. We offer some management actions of influencing ecological and economic systems that ensure sustainable development. The authors determined that at the regional level it is necessary to revise and increase the normative fees for natural resources, as well as to increase the size of fines for violation of environmental legislation. We have carried out clustering of municipal districts by economic indicators affecting the number of biological resources, and we propose the necessary priority management actions based on the obtained models.

Frequency vs. Size of Bank Fines in Local Credit Markets

We examine how banking supervisors affect credit at the local level by charging fines to individual banks. Using a macro approach to capture the direct effect on the fined bank and the indirect effect on the other banks operating in the local credit market, we estimate reputational, reallocation and balance sheet effects on Italian provinces over the period 2005–2016 by a fixed effects model and instrumental variables. Provincial gross bank loans expand after a fine independently of its size. The impact of fine frequency depends on the size of the provincial banking sector, but neither on bank governance/ownership nor crises. No statistically significant evidence supports reputational or balance sheet effects. Instead, our results suggest that it would behoove bank supervisors to favor frequency over size of bank fines. Bank fines seem to work more like a good housekeeping seal of approval, enhancing transparency and effective banking practices.

Characteristics of the Coal Fines Produced from Low-Rank Coal Reservoirs and Their Wettability and Settleability in the Binchang Area, South Ordos Basin, China

By using proximate analysis, X-ray diffraction mineral analysis, scanning electron microscope, contact angle measurement, and settlement simulation experiment, the coal fines produced from the coalbed methane wells of Binchang area were used to study the characteristics including particle size distribution, composition, morphology, wettability, and settleability. The results show that the particle size of coal fines produced from coalbed methane wells are mainly >20 mesh, ranging of 1-400 μm, and the particle size distribution curve is mainly dominated by the main-secondary bimodal type, with the main peak of 30-300 μm. The particle size from large to small is drill cutting coal fines, flowback coal fines, bailing coal fines, and pipeline filter coal fines. In terms of ash content, coal fines are higher than coal seam, and drilling cuttings are higher than bailing coal fines, while the fixed carbon content of the former is lower than that of the latter. The minerals of coal fines are mainly kaolinite, illite, quartz, and other 6 minerals, and the mineral types of drilling coal fines are the most abundant, while the bailing coal fines only contain illite and quartz. The roundness of coal fine particles ranges from excellent to poor in the order of bailing coal fines, pipeline filter coal fines, flowback coal fines, and drilling cuttings. However, the sorting of drilling cuttings is excellent, and the particle edges are straight, neat, and smooth, while the sorting of bailing coal fines is poor, and the particle edges are curved, uneven, and rough. The contact angles of coal fines are 40.25°-69.5°, indicating hydrophilous. The wettability of bailing coal fines is better than that of drilling cuttings. The particle size has a negative correlation with the wettability effect. The more obvious the modification effect of positive wetting agent is, the worse the modification effect of negative wetting agent is. The modification of surfactant has nothing to do with the particle size of the coal fines, but is closely related to organic components and minerals. The larger the coal particle size, the higher the settling rate, and the higher the ash content and the lower the fixed carbon content, the faster the settling rate. With the dividing point 150 mesh, the settling rate of large particles is mainly affected by particle size, while that of small particles is affected by the composition.

Undrained cyclic response of a dense saturated sand with various grain sizes and contents of nonplastic fines: Experimental analysis and constitutive modeling

The densification can increase the liquefaction resistance of sands. However, in most engineering practice, sands are not pure and contain a significant amount of fines with particle diameter smaller than 0.075 mm. Thus, it is necessary to quantitatively evaluate the influence of fines on the undrained cyclic behavior of dense sandy soils. In this study, a series of undrained cyclic triaxial tests were conducted on the dense saturated sand with various mean grain sizes and contents of nonplastic fines. A unified constitutive framework is modified to improve the capability of simulating the cyclic mobility behavior of sandy soils. The results indicate that the effect of the mean grain size on the cyclic stress ratio required to cause 5% double-amplitude axial strain for sandy soils depends on the amount of nonplastic fines added. Moreover, a good correlation between the cyclic resistance ratio and the initial value of the equivalent granular state parameter is obtained for various fines contents and mean grain sizes of nonplastic fines. The influence of the fines content and mean grain size of nonplastic fines on the liquefaction resistance of sandy soils can be reasonably characterized by the constitutive framework using a set of unique parameters. Additionally, the capability of the constitutive framework for describing the influence of the fines content on the cyclic instability behavior of sandy soils is also evaluated against the experimental data in the literature.

EFFECTS OF PARTICLE SIZE AND TYPE OF AGGREGATE ON MECHANICAL PROPERTIES AND ENVIRONMENTAL SAFETY OF UNBOUND ROAD BASE AND SUBBASE MATERIALS: A LITERATURE REVIEW

Unbound graded aggregates are used to construct the base and subbase of road pavement. The mechanical properties of unbound graded aggregates depend significantly on aggregate size and grading, especially on the maximum particle size (Dmax) and fines content (Fc; typically, the particle size of fines < 0.075 mm). Nowadays, not only natural aggregates (NA) but also recycled aggregates (RA) from construction and demolition waste are used in road construction. Many studies have been done to characterize the mechanical properties of RA, but a comprehensive understanding of the effects of aggregate size and grading on the mechanical properties has not been fully achieved due to the wide variety of material types and properties of RA. Therefore, this paper searched previous studies and reviewed the effects of particle size, type of aggregate, and mixing proportions of RA on mechanical properties such as compaction, bearing capacity, resilient modulus, and shear strength. In addition, some information on the environmental safety of RA, such as leachate pH and leaching of elements, are summarized. The results collected from the literature indicate that the mechanical properties of RA and their mixtures are mostly comparable to those of NA and can be used to construct road base and subbase. As well as the type of aggregate, Dmax of RA was also found to affect highly the relationships between the mechanical indices (e.g., the maximum dry density and California bearing ratio) and Fc and/or mixing proportion.

Some reflections on improving the provisions of the code of Ukraine on administrative offenses in terms of increasing liability for violation of legislation in the field of protecting natural ecosystems from fires

The article presents an analysis of the current state of the current administrative legislation of Ukraine, which regulates relations in the field of environmental protection and rational nature management in the state. The author has analyzed the provisions of the draft Law of Ukraine “On Amendments to the Code of Ukraine on Administrative Offenses in relation to increasing liability for violation of legislation in the field of protecting natural ecosystems from fires” and a number of other bills. Their development and adoption is an important step towards bringing the current national legislation in line with European standards and norms, as well as further development of social and economic transformations in Ukraine in the environmental sphere.&#x0D; Also in this article the author indicates the feasibility of amending the Code of Administrative Offenses of Ukraine and other legislative acts in terms of strengthening administrative responsibility for violating fire safety rules, protecting the environment, preventing fires in natural ecosystems in the country. With regard to improving the efficiency of management of the sphere of protecting natural ecosystems from fires, the author points out the need to provide additional powers to the bodies of the State Emergency Service of Ukraine for the implementation of state control and supervision over the state of fire safety at forestry facilities. In this aspect, it is timely to develop and adopt a separate legislative act to secure the rights and obligations of the relevant officials to exercise such state control and determine the procedure for its organization. In addressing the issue of protecting natural ecosystems from fires, it is proposed to pay attention to the need to ensure strict adherence to the principle of inevitability of administrative responsibility for violation of legislation on environmental protection, eliminating the imbalance between the actual amount of damage caused to the environment and the amount of sanctions; an increase in the size of fines for setting fires in natural ecosystems, including for unauthorized burning of stubble on agricultural land (fields) by their owners.

The role of fine excipient particles in adhesive mixtures for inhalation

AbstractDespite the fact that adding fines improve the drug dispersion performance during inhalation, the scarcity of mechanistic insight into the formulation process, independent of the aerosolization, has kept the dispute on the underlying improvement mechanism open. We therefore simulate ternary formulations (carrier, drug, fines) in a vibrational cell to explore the mixing mechanism and the effect of particle size and loading ratio of fines on formulation performance. Results suggest that the buffer theory is a critical contributory mechanism since it curtails the carrier's collision rate and, therefore, decreases agglomerate breakage. Consequently, relatively larger drug aggregates are formed over the carrier, which eventually experiences greater detachment forces. A simple dispersion test is performed to evaluate drug detachment rate at wall‐collision. An excess of cohesive fines, or using larger fines, diminishes the rotational kinetic energy of coarse particles by lumping them together. This reduces drug agglomerate breakage and leads to poor mixing.

The change of fracture conductivity caused by coal fines with different particle sizes displaced by single-phase water

Ascertaining the change of fracture conductivity caused by coal fines with different particle sizes displaced by single-phase water can provide a theoretical basis for studying the migration characteristics of coal fines in coal fractures. A single-phase water displacement device was used to measure the effects of changes in parameters such as the displacement time, the mass concentration of coal fines in the output fluid and the cumulative water yield when the coal fines were driven by single-phase water with six different particle sizes. The changes of permeability and fracture conductivity of resin–coal core samples caused by mixtures of water and coal fines with different particle sizes were calculated and analyzed. The results demonstrated that, with the decrease of the particle size of coal fines, the required time for the fracture to be completely sealed in the resin–coal core sample and the mass concentration of coal fines in the output fluid are increasing; the grinding effect of coal fines with particle size 200 mesh can pass through the cracks, and the cumulative water yield is higher when these two kinds of coal fines are displaced. The fracture conductivity of resin–coal core sample caused by coal fines with different particle sizes displaced by single-phase water shows the same characteristics of “slowly rising–rapidly rising–reaching a peak and starting to decrease–reducing to zero”. In the displacement process of fines at 200 mesh, the fracture conductivity increases rapidly in the early stage and decreases slowly in the later stage. In the displacement process of 80–100 mesh coal fines, the fracture conductivity increases slowly in the early stage and decreases rapidly in the later stage.

On the use of an agro waste, Miscanthus x. Giganteus, as filtrate reducer for water-based drilling fluids

During drilling operations, the influx of liquids to the producing zones can cause wellbore instability problems and decrease the well’s productivity. Different additives are used as filtrate reducers in water-based drilling fluids (WBFs). The growing need of more sustainable drilling operations motivates the incorporation of residues and waste in WBFs formulations. This study reports the evaluation of Miscanthus x. Giganteous (MxG) fines as filtrate reducers in WBFs, promoting the valorization of this agro waste. MxG was characterized by FTIR, and the spectra exhibited characteristic bands of its major constituents. The MxG size reduction was performed by grinding and sieving it through #100, 200 and 325 mesh screens, and the particle size distribution was obtained by optical microscopy. TGA results showed that the sieved MxG grass fines exhibited thermal stability in the range for use in deep and ultra-deep wells, and the degradation profiles were dependent on the average particle size. The filtration properties of all WBFs studied were well described by Darcy’s law, allowing the determination of the spurt loss volume. The filtration performance of the WBFs was significantly improved when the average particle size of the MxG fines decreased, exhibiting comparable or superior results than other materials obtained by more complex, solvent-dependent, expensive and time-consuming processes described in literature.

Evaluation of grain size and content of nonplastic fines on undrained behavior of sandy soils

Marine sandy soils may liquefy under wave loading and/or seismic loading. Current research shows that the presence of fines can significantly affect the liquefaction potential of sandy soils. Thus, a quantitative evaluation of the effect of fines on the undrained behavior of sandy soils can provide useful information on soil liquefaction that can advance the design of foundations of coastal structures. However, little is known about how the grain size of nonplastic fines affects the mechanical behavior of sandy soils. In this study, a series of strain-controlled monotonic undrained triaxial compression tests and critical-state constitutive modeling are carried out on a medium dense saturated sandy soil for various fines contents (FCs), mean grain sizes ( s) of nonplastic fines, and initial effective confining pressures. The results show that the peak deviatoric stress decreases significantly with decreasing especially for high FCs. The equivalent granular state parameter (ψ*) at the phase transformation can be used to characterize the effect of fines on the dilatancy of sandy soils in constitutive modeling. Additionally, the initial value of ψ*() serves as physical index for characterizing the influence of fines on the undrained instability state of sandy soils.