Soil Plasticity Research Articles

Comparison of Plastic Waste Processing Machine Models in The Producing of Plastic Grains and Oil Fuel and Its Cost Analysis

Alat pengolah sampah plastik melalui proses pemanasan dan destilasi dapat menghasilkan butir plastik dan bahan bakar minyak sebagai alternatif solusi lain untuk masalah sampah plastik. Pengujian kinerja dari 3 (tiga) buah model mesin pengolah sampah plastik (model I, II, and III) yang masing-masing dilengkapi dengan satu, dua, dan tiga tabung distilasi, dilakukan untuk membandingkan hasil produksi butir plastik dan bahan bakar minyak yang dapat dihasilkan. Selanjutnya, biaya ekonomiannya dianalisis menggunakan besaran nilai titik impas (break even point). Hasil pengujian menunjukkan bahwa Model I menghasilkan butir plastik tertinggi, yaitu sebesar 2,76 kg dan Model III menghasilkan bahan bakar minyak tertinggi, yaitu sebesar 51 mL. Hasil uji statistik diperoleh bahwa tidak ada perbedaan yang signifikan antara Model I, II, dan III terhadap kuantitas butir plastik dan bahan bakar minyak dengan hasil (p>α; (1,000 > 0,05). Hasil analisis keekonomian menunjukkan bahwa titik impas (break even point) dari masing-masing model (I, II dan III) akan tercapai dalam waktu 44,47 dan 35 hari dengan waktu operasi selama 8 jam per hari dan 10,5 kg/hari sampah plastik. Secara ekonomi, model III menunjukkan pengembalian investasi yang relatif lebih cepat dibandingkan model I dan II. Hasil penelitian ini bermanfaat bagi pengembangan perancangan mesin pengolah sampah plastik untuk skala yang lebih besar di industri. Selain itu, diharapkan juga dapat memberikan nilai tambah ekonomi masyarakat dan alternatif solusi bagi permasalahan sampah plastik di Indonesia. Abstract A plastic waste processing apparatus, employing heating and distillation processes can yield plastic grains and oil fuel, providing an alternative solution to the plastic waste problem. Performance tests were conducted on 3 (three) models of plastic waste processing machines (Models I, II, and III) equipped with one, two, and three distillation cylinders, respectively, to compare the quantity of plastic grains and oil fuel produced. Furthermore, an economic cost analysis was also conducted by using the break even point as a metric. The results showed that Model I yielded the highest quantity of plastic grains (2.76 kg), and Model III produced the highest amount of oil fuel (51 mL). Statistical tests indicated no significant differences (p>α; 1.000 > 0.05) among Models I, II, and III concerning the quantities of plastic pellets and oil fuel. Economic analysis demonstrated that the break-even points for each model (I, II, and III) would be attained in 44, 47, and 35 days, respectively, assuming an 8-hour daily operation and processing 10.5 kg/day of plastic waste. Model III economically showed a relatively more cost-effective compared to Models I and II. The findings of this research can be applied to the development of mass-production of plastic grains and oil fuel from plastic waste on an industrial scale. This research could be contributed to the increas in community economic value and offer an alternative solution to the plastic waste issue in Indonesia.

Conversion of LDPE Plastic Oil to Gasoline by Supercritical Water Liquefaction

LDPE (Low Density Polyethylene) is one of the plastic waste that is often found in the surrounding environment. Based on data from the National Waste Management Information System (SIPSN) in 2022, waste in Indonesia reached 17.834.071 tons/year with 18.5% being plastic waste. Plastic waste management generally uses recycling. However, recycling plastic waste is not efficient enough in tackling plastic waste in Indonesia. Recently, a promising alternative recycling method for the future is pyrolysis, a process to convert plastic into fuel oil. However, the pyrolyzed oil still contains impurities that reduce the quality of the oil. As an effort to improve the quality of pyrolysis oil, the author proposes the addition of zeolite catalyst in the pyrolysis process followed by the Supercritical Water Liquefaction (SWL) method. The zeolite catalyst aids the degradation process thereby accelerating the reaction rate. The SWL method is able to convert plastic waste into low molecular weight chemicals. The results obtained will be analyzed by gas chromatography mass spectroscopy (GC-MS) to determine the length of the carbon chain in the sample. Based on the chromatography data, it is found that the number of peaks and retention times show carbon chains ranging from C8-C12, from these results it can be identified that the sample is included in kerosene or kerosene compounds. After the SWL process, the percentage of kerosene and diesel is reduced to 11% gasoline. So the Supercritical Water Liquefaction process is proven to break down long hydrocarbon chains into lighter ones.

Experimental assessment of copper oxide nanoparticles on the attributes of diesel engines fuelled with waste plastic biodiesel

The current research work concentrates on the potentiality of waste plastic oil (WPO) as a viable source. Waste plastic oil is obtained by using the pyrolysis technique. The different fuel properties are determined and contrasted with diesel. Initially, different blends of waste plastic biodiesel blends (WPO10, WPO20 and WPO30) were tested on diesel engines at ideal conditions. From test results, the optimised WPO20 blend is further investigated with the addition of copper oxide (CuO) nanoparticles at two levels, 30 and 60 ppm, by using an ultrasonication process. Test results inferred that BTE for the WPO20 CuO 30 ppm is enhanced by 3.23% over WPO20. Furthermore, the harmful emissions of CO, HC and smoke are reduced drastically by 27.95%,11.11% and 5.7%, respectively over diesel. Overall, the use of WPO20 CuO nanoparticles shows positive attributes of diesel engines.

Fertigation frequency is a useful tool for nitrate management in intensive open-field agriculture

The main source of nitrogen for most cultivated plants is nitrate. Agriculture has overused this nutrient, resulting in serious environmental problems in various parts of the world. The common practice in open intensive horticultural fields with clay-loam soils with a high water retention capacity (e.g., high percentage of clay) is to irrigate two to four times per week. Technically and logistically, this is much easier than one or more irrigation events per day. However, the loss of nutrients and water below the root zone may occur, with the consequent loss of efficiency. In this work, two cultivation cycles in an open-field endive crop were carried out under plastic soil mulching. We compared three fertigation strategies based on different frequencies of fertigation events; low fertigation frequency (LF, two to three fertigation events per week that simulates common farmer practice), medium fertigation frequency (MF, one fertigation event per day), and high fertigation frequency (HF, three fertigation events per day). The three fertigation strategies applied equal water and fertilizers doses per week. The high fertigation frequency increased volumetric water content in the upper soil profile, while the low fertigation frequency in the lower soil profile. The results demonstrated that HF fertigation increases shoot fresh weight (harvest yield) by increasing shoot water content, but did not improve shoot nutrient uptake or nitrogen nutritional status. The important finding, from the environment point of view, is that high and medium fertigation frequencies decreased nitrate concentration in the root influence zone, where it may be prone to leaching due to heavy rain events.

Mimicking real-field degradation of biodegradable plastics in soil and marine environments: From product utility to end-of-life analysis

Biodegradable plastics can mitigate plastic waste issues by undergoing hydrolysis and microbial digestion. However, biodegradable plastics face unjust accusations of not decomposing in natural environments, including barren soil or cold oceans, under unsuitable conditions. In this study, we simulated end-of-life of biodegradable plastic products under real-field soil and seawater conditions. Replenishing vermicompost in horticultural topsoil (3:7 wt ratio) activated microbial growth, resulting in significant degradation. In fertile soil, polycaprolactone (PCL) and poly(butylene succinate) (PBS) required fewer than 6-months, for complete degradation, while poly(butylene adipate-co-terephthalate) (PBAT) with more than 51 mol% terephthalate content was rarely degraded. In an artificial seawater aquarium, PCL degraded at the rate of 30 μm per month. The degradation of bioplastics enclosed in coarse nets was superior to that in fine nets, owing to higher aeration and water circulation. Sea waves and current significantly accelerated the rate of PCL-degradation to 89 μm per month in a coastal marine environment; the ranking of rate of decomposition was PCL > PBS > PBAT. After 12 months of biodegradation, the tensile strength and elongation of a 2 mm-thick sample of PCL decreased to 15 MPa and almost 0 %, respectively. 3D-printed jars, designed for octopus fishing, is widely used and its designed mechanical decay aids in preventing the ghost fishing of abandoned gear as demonstrated by artificial conches, illustrating the potential for biodegradable fishing gear.

Bio-inspired Predictive Models Development for Strength Characterization of Cement Deep-Mixed Plastic Soils

Bio-inspired Predictive Models Development for Strength Characterization of Cement Deep-Mixed Plastic Soils

Experimental investigation of fuel injection timing effects on a CRDI diesel engine running on hydrogen-enriched waste plastic oil

In response to fossil fuel concerns and the imperative of effective plastic waste management, this study investigates the impact of hydrogen-plastic oil (WPO) blends on a CRDI diesel engine. Six combinations (WPO10, WPO20, WPO30, WPO10 + H2, WPO20 + H2, WPO30 + H2) are examined across varying loads and fuel injection timings. Notably, WPO10 + H₂ (H2 energy share i.e., 8 lpm) exhibits a 15.1 % increase in brake thermal efficiency, an 11.2 % fuel consumption reduction, improved peak cylinder pressure (66 bar), and maximum heat release rate (40.16 J/°CA) compared to diesel. It also shows reduced emissions of CO, HC, CO2, and smoke opacity—34.8 %, 15.1 %, 10.7 %, and 28.5 %, respectively, relative to diesel. Elevated nitrogen oxide (NOx) emissions are observed across all blends. This study underscores the environmental benefits of blending waste plastic oil with diesel, promoting recycling, reducing reliance on traditional diesel, lowering greenhouse gas emissions, and supporting sustainability. Advanced fuel injection timing at higher loads slightly mitigates NOx emissions, while increasing the blend proportion leads to prolonged ignition delays, reduced thermal efficiency, and heightened emissions.

The influence of viscous behavior and static shear stress on the cyclic strengths of plastic soil: a numerical study

An accurate understanding of the cyclic behavior of clays and plastic silts is important for system performance predictions during earthquake loading. This paper presents the results of a numerical investigation into the individual and combined influences of static shear stress and viscous strength gain on the cyclic resistance of clays and plastic silts. Using the viscoplastic constitutive model PM4SiltR implemented in the finite difference program FLAC 8.1, the cyclic behaviors of the plastic soils were simulated using single-element cyclic direct simple shear simulations. A parametric analysis was performed with different combinations of viscous strength gains and static shear stresses. The effects of static shear stress and viscous strength gain varied under monotonic and cyclic loading conditions. Numerical findings suggest empirical correlations developed using scant laboratory data may not accurately predict the reduction of cyclic strengths with increasing static shear stress. Furthermore, sizable magnitudes of monotonic viscous strength gains only produced a marginal increase in cyclic strengths. The findings from this study highlight the need for future experimental laboratory testing to validate the numerical findings, to improve the accuracy of performance predictions of geosystems constructed with clays and plastic silts during and following earthquake loading.

Mechanistic understanding on the uptake of micro-nano plastics by plants and its phytoremediation.

Contaminated soil is one of today's most difficult environmental issues, posing serious hazards to human health and the environment. Contaminants, particularly micro-nano plastics, have become more prevalent around the world, eventually ending up in the soil. Numerous studies have been conducted to investigate the interactions of micro-nano plastics in plants and agroecosystems. However, viable remediation of micro-nano plastics in soil remains limited. In this review, a powerful in situ soil remediation technology known as phytoremediation is emphasized for addressing micro-nano-plastic contamination in soil and plants. It is based on the synergistic effects of plants and the microorganisms that live in their rhizosphere. As a result, the purpose of this review is to investigate the mechanism of micro-nano plastic (MNP) uptake by plants as well as the limitations of existing MNP removal methods. Different phytoremediation options for removing micro-nano plastics from soil are also described. Phytoremediation improvements (endophytic-bacteria, hyperaccumulator species, omics investigations, and CRISPR-Cas9) have been proposed to enhance MNP degradation in agroecosystems. Finally, the limitations and future prospects of phytoremediation strategies have been highlighted in order to provide a better understanding for effective MNP decontamination from soil.

Prediction of the Subgrade Soil California Bearing Ratio Using Machine Learning and Neuro-Fuzzy Inference System Techniques: A Sustainable Approach in Urban Infrastructure Development

In the realm of urban geotechnical infrastructure development, accurate estimation of the California Bearing Ratio (CBR), a key indicator of the strength of unbound granular material and subgrade soil, is paramount for pavement design. Traditional laboratory methods for obtaining CBR values are time-consuming and labor-intensive, prompting the exploration of novel computational strategies. This paper illustrates the development and application of machine learning techniques—multivariate linear regression (MLR), artificial neural networks (ANN), and the adaptive neuro-fuzzy inference system (ANFIS)—to indirectly predict the CBR based on the soil type, plasticity index (PI), and maximum dry density (MDD). Our study analyzed 2191 soil samples for parameters including PI, MDD, particle size distribution, and CBR, leveraging theoretical calculations and big data analysis. The ANFIS demonstrated superior performance in CBR prediction with an R2 value of 0.81, surpassing both MLR and ANN. Sensitivity analysis revealed the PI as the most significant parameter affecting the CBR, carrying a relative importance of 46%. The findings underscore the potent potential of machine learning and neuro-fuzzy inference systems in the sustainable management of non-renewable urban resources and provide crucial insights for urban planning, construction materials selection, and infrastructure development. This study bridges the gap between computational techniques and geotechnical engineering, heralding a new era of intelligent urban resource management.

The influence of plastic pyrolysis oil on fuel lubricity and diesel engine performance.

This study investigates the viability of using plastic oils derived from High-density polyethylene (HDPE), Polypropylene (PP), and Polystyrene (PS) as alternative fuels for diesel engines. The research focuses on comparing the physical and chemical properties, fuel lubricity, engine performance, combustion characteristics, and exhaust emissions of these plastic oils. Analysis revealed that PS exhibits different fuel properties compared to diesel, with a carbon range distribution similar to gasoline, while HDPE and PP properties closely resemble diesel fuel. To prevent potential engine damage, PS was excluded from engine tests. PP displayed the best fuel lubricity, attributed to its higher kinematic viscosity and sulphur content, reducing direct friction. Diesel followed, with PS and HDPE in decreasing order of lubricity. Diesel's lubricity was influenced by the 7% palmitic methyl ester content in the fuel. In engine tests, HDPE demonstrated BTE similar to diesel, while PP exhibited lower BTE due to combustion retardation, leading to increased energy losses and higher BSFC. The combustion characteristics, in-cylinder pressure, and heat release rate of HDPE closely resembled diesel, while PP showed significantly delayed combustion due to low oxygen content and higher kinematic viscosity. Notably, NOX emissions from PP were lower than diesel and HDPE at all engine loads due to heat losses, resulting in a low in-cylinder temperature unsuitable for NOX emission. HDPE produced higher NOX emissions than diesel at low and middle loads due to its higher H/C ratio, promoting high thermal NOX formation. HC emissions from both HDPE and PP were higher than diesel due to increased fuel supply, hindering chemical bond breakdown. Similarly, CO emissions increased for HDPE and PP due to insufficient time for complete combustion, with HDPE producing more CO due to its heavy composites and lower cetane index. Smoke emissions from both HDPE and PP surpassed diesel, attributed to lower oxygen and higher sulphur content, leading to increased sulphurate particulate matter formation, and lower fuel density referring to the high amount of fuel supplied to the engine.

Optimization of RHA and Cement proportion for soil stabilization

The process of changing a soil’s physical characteristics to provide it long-term, permanent improvements in strength is known as soil stabilisation. Increasing a soil’s overall bearing capacity and shear strength is how stabilisation is achieved. After stabilisation, a solid monolith forms, reducing permeability and hence the possibility for shrinkage and swelling as well as the damaging impacts of freeze-thaw cycles. The goal of this study is to improve the physical characteristics of soils for better building results by investigating the potential of cement and rice husk ash (RHA) as soil stabilizing materials. Using RHA, a byproduct of milling rice, this study investigates alternate, environmentally friendly stabilization techniques with respect to the limits of traditional cement-based stabilization. The study assesses the impacts of different RHA and cement mixtures on soil’s Liquid Limit, Plastic Limit, and Plasticity Index using a thorough experimental approach. The factorial experiment provides important insights into changes in soil plasticity over a 3x3 matrix under nine distinct settings. The results show that while larger RHA percentages considerably lower the Plasticity Index, indicating improved soil stability, increasing cement concentration generally rises the Liquid and Plastic Limits. The satisfactory combination, determined to be 15% RHA and 8% cement, presents a possible path closer to producing soil that is less plastic and more durable. This obseravtion helps to broaden sustainable, low-cost techniques of stabilizing soil at the same time as also shedding light on the synergistic impacts of cement and RHA on soil parameters.

Addressing Marine Pollution in the Context of the UN Ocean Decade

The United Nations Decade of Ocean Science for Sustainable Development (2021-2030), known as the “Ocean Decade”, represents a significant global initiative aimed at mobilising ocean science to foster sustainable development. One of the key challenges highlighted by this initiative is marine pollution, which poses severe threats to ocean ecosystems, biodiversity, and human livelihoods. Marine pollution has escalated over the past decades, primarily driven by anthropogenic activities, including plastic waste, chemical runoff, oil spills, and untreated wastewater discharges. Addressing these challenges requires not only robust scientific research but also coordinated international efforts to implement practical and long-term solutions.

Quantification of the composition of pyrolysis oils of complex plastic waste by gas chromatography coupled with mass spectrometer detector.

Waste valorisation through pyrolysis generates solid, liquid and gaseous fractions that need to be deeply characterised in order to try to recover secondary raw materials or chemicals. Depending on the waste and the process conditions, the liquid fraction obtained (so-called pyrolysis oil) can be very complex. This work proposes a method to quantitatively measure the composition of pyrolysis oils coming from three types of polymeric waste: (1) plastic packaging from sorting plants of municipal solid waste, (2) plastic rich fractions rejected from sorting plants of waste of electrical and electronic equipment and (3) end-of-life carbon/glass fibre reinforced thermoset polymers. The proposed methodology uses a gas chromatography (GC) coupled with mass spectrometer detector (MS) analytical technique, a certified saturated alkanes' mix, an internal standard and fourteen model compounds. Validation of the methodology concluded that the average relative error was between -59 wt% and +62 wt% (with standard deviations between 0 wt% and 13 wt%). Considering that the state-of-the-art scenario to quantify complex plastic pyrolysis oils as a whole is almost none and that they are usually evaluated only qualitatively based on the area percentage of the GC-MS chromatograms, the presented quantification methodology implies a clear step forward towards complex pyrolysis oil compositional quantification in a cost-effective way. Besides, this quantification methodology enables determining what proportion is being detected by GC-MS with respect to the total oil. Finally, the presented work includes all the Kováts RI for complex temperature-program gas chromatography of all the signals identified in the analysed pyrolysis oils, to be readily available to other researchers towards the identification of chemical compounds in their studies.

Effect of Waste Plastic Decomposition Oil fuel Property on Exhaust Characteristics for small 2-stroke Engine

Effect of Waste Plastic Decomposition Oil fuel Property on Exhaust Characteristics for small 2-stroke Engine

Improving plastic pyrolysis oil quality via an electrochemical process for polymer recycling: a review

In this review we discuss the application of electrochemical hydrogenation for pyrolysis oil upgrading, thus facilitating a circular polymer economy and low-carbon fuel production.

Tire modeling for an autonomous tractor suitable for soft soils

Off-road autonomous vehicles such as tractors and agricultural machinery require an important power traction to cope with mobility issues on soft soils and rough terrains. This paper presents a simplified version of tyre modeling as an adapted Burckhardt tire model based on an analytical Bekker-Wong wheel-soil interaction model. The Bekker-Wong model is a fractional model in space and takes into account the plasticity theory and soil mechanics, however such a model is too complex to be usable in real-time. An adapted version of the Burckhardt model helps having a more compact model that can be usable in real-time. In this paper, an adapted Burckhardt tire model has been optimized for the E-Tract simulator and experiments have been carried out to validate the tractor simulator.

Guar Gum, Gellan Gum Biopolymer Soil Stabilization

In civil engineering and construction, soil stabilization is an important aspect. There are diverse conventional techniques to improve soilproperties and for soil stabilization. This study explores the viability of twotypes of biopolymers, Guar gum and Gellan gum, as sustainable and ecofriendly additives for clayey soil stabilization. Compaction, unconfined compression test, permeability, consistency limit, consolidation tests were performed in the study. The sample for the test has been prepared that biopolymer has been mixed with soil in different proportions. These biopolymers forms hydrogels when they get activated, and it enhances the bonding between soil particles thereby increasing the strength. Treating soilwith biopolymer increases dry unit weight and decreases optimum moisturecontent (OMC).Addition of gum solution reduces friction between soil particles, leading to marginal increase in dry unit weight. Higher the biopolymer content lower is the OMC content and soil become more stiff. The compressive strength and load bearing capacity isfound increasing soilbiopolymerspecimen upon different days of curing. For every tested percentage of treatment the percentage reduction factor rises withbiopolymer concentration due to drop in void ratio that results in a drop in the soil's permeability. Guar Gum and Gellan Gum are used as stabilizers in soil treatment, increasing liquid and plastic limits, shrinkage limit, and viscosity. They activate hydrogels, strengthen bonding activity, and increaseshrinkage limit. The addition of Guar Gum and Gellan Gum improves soil biopolymer mix viscosity and adhesion. The findings of this study positivelyimply that adding this material to weak soil would improve the soil’s characteristics.

Advancements in Soil Stabilization: The Efficacy of Fly Ash and GGBS

Engineered soil qualities can be modified mechanically, chemically, or biologically to achieve soil stabilisation. Soil stabilisation is a method used in civil engineering to enhance and enhance a soil’s structural qualities. Mechanical strength, permeation, compressibility, resilience, and plasticity are some of these attributes. The systematic investigation of soil stabilization with fly ash and ground granulated blast furnace slag (GGBS) as binders is presented in this work. The goal of using geopolymer technology is to enhance the mechanical qualities of clay soils for the building of road pavement by substituting conventional cementitious materials. The ideal ratio of Fly Ash to GGBS is found using a Taguchi experimental design technique, more precisely a L9 Orthogonal Array, with the goal of improving soil liquid limit, plastic limit, and plasticity index. The effectiveness of various Fly Ash and GGBS ratios is assessed, as well as their influence on soil behavior. In order to develop models for predicting soil parameters, regression analysis is used. Diagnostic plots show a reasonable fit but also highlight small amounts of unexplained variability. These discoveries have important ramifications for sustainable construction methods and are essential for improving soil stabilizing procedures, especially when it comes to road pavement engineering.

A comprehensive study on the impact of waste plastic oil on engine wear

A comprehensive study on the impact of waste plastic oil on engine wear