Optimal Coalition Structure Generation (CSG) is a significant research problem in multi-agent systems that remains difficult to solve. This problem has many important applications in transportation, ...eCommerce, distributed sensor networks and others. The CSG problem is NP-complete and finding the optimal result for
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possible partitions. The ODP–IP algorithm (Michalak et al. in Artif Intell 230:14–50, 2016) achieves the current lowest worst-case time complexity of
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Imperfect algorithm
means that there are some contrived inputs for which the algorithm fails to give the optimal result. We benchmarked ImDP against ODP–IP and proved its efficiency. Experimental results confirmed that ImDP algorithm performance is better for several data distributions, and for some it improves dramatically ODP–IP. For example, given 27 agents, with ImDP for agent-based uniform distribution time gain is 91% (i.e. 49 min).
The corn crop biomass (CB) is widely used as a feedstock for biochemicals such as lactic acid, succinic acid, citric acid, xanthan gum, and biofuels likely bioethanol, butanol, and biogas. Since CB ...provides a resistive structure for enzymatic and microbial attack, ultrasonic treatment can assist to break the recalcitrance structure. Several techniques such as imaging (atomic force microscopy—AFM; scanning electron microscopy—SEM), spectroscopy (energy-dispersive X-ray spectroscopy—EDX; Fourier transform infrared spectroscopy—FTIR; Raman spectroscopy; X-ray diffraction—XRD), and thermal (TGA) were studied to characterize the ultrasonicated CB. A detailed analysis of different techniques on their potential benefits will assist the researchers to select a suitable technique to optimize the ultrasonication for various applications. The basic mechanisms behind ultrasonication, benefits, downsides, practical considerations, and factors that should be deliberated in the future studies are discussed. Sonication enhanced the hemicellulose and cellulose yield, saccharification rate, and delignification of CB. AFM, EDX, FTIR, Raman spectroscopy, SEM, TGA, and XRD described the variations in topographical features, elemental composition, molecular structure, microstructure, thermal steadiness, and degree of crystallinity, respectively, of the ultrasonicated CB. The quantitative crystallinity of CB can be analyzed through XRD and Raman spectroscopy, whereas the qualitative crystallinity and molecular structural comparisons are studied using FTIR. Imaging techniques can provide important aspects such as lignin relocalization and cell wall delamination. Integrating EDX with SEM is beneficial to determine the elemental percentage composition altered in CB due to ultrasonication.
Graphical abstract
With increases in population and industrialization, global energy demand is increasing rapidly and resulting in various environmental challenges related to fossil fuel consumption. These challenges ...have made it imperative to look for alternative means of environmentally sustainable energy production, such as the thermal degradation of biomass. Biofuels obtained from pyrolysis have the potential to be substituted for fossil fuels, but one of the major barriers to utilization of pyrolysis oil is the presence of oxygenated compounds. An approach to overcome this is to co-pyrolyze the biomass with hydrogen-rich feedstocks such as plastic and tire wastes. Studies have shown that exists a synergistic relationship between plastics/tires and biomass as well as resulting products from co-pyrolysis have higher heating value along with improved bio-oil properties. This paper discusses the current progress on the co-pyrolysis of biomass with waste plastics/tires and their synergistic interactions for high grade fuel production. Co-pyrolysis studies done on pilot-scale have also been discussed in this review.
The bioprospects of condensed corn distillers solubles (CCDS) from novel selective milling technology was investigated using a modified lab-scale separation. The valued-added products such as mineral ...fraction (MF), protein fraction (PF), and solvent-extracted fraction (SEF) were obtained. Including characterization of fractions, the enzymatic hydrolysis of PF using trypsin was done to examine the potential of bioactives. The yields of PF, MF, and SEF were 25.43, 8.59, and 65.09%, respectively from CCDS. Glu, Leu, and Pro were the most abundant amino acids (AAs) of PF, thereby expecting greater possibility of bioactives. The significant presence of potassium, phosphorous in MF, and extractable 2,3-butanediol, glycerol in SEF shows promising future applications. Besides, the protein hydrolysate from PF had VFVDHPLFLER, NPESFLSSFSK, ILHTISVPGEFQFFFGPGGR, TGGLGDVLGGLPPAMAANGHR, and FAFSDYPELNLPER as the identified peptides with antioxidant characteristics and inhibition against ACE, DPP-III, and DPP-IV. The bioactivities forecasted by BIOPAP software were verified with larger contents of hydrophobic, aromatic, and other AAs in PF. The porous and amorphous nature of MF and PF as found by microstructural study revealed potentiality of these products for nutritional purposes for feed industries. The prospective of CCDS can be anticipated as per the outcomes and further optimization for value-chain can be established.
Graphical abstract
Interest in hydrothermal carbonization (HTC) is increasing worldwide due to its outstanding capabilities. This study introduces a novel semi-continuous feeding system to feed the biomass slurry ...against the high pressure of an HTC reactor. As expected in a semi-continuous operation, the biomass would be instantaneously exposed to the desired pressure and temperature, instead of a gradual increase to the desired temperature. Higher degrees of carbonization, lower cellulose crystallinity, improved hexagonal graphene sheets, surface hydrophobic characteristics, and higher thermal stability were observed at elevated temperatures in products from semi-continuous HTC when compared with products from batch operation. Reaction pathways were proposed for both batch and semi-continuous operations on the basis of physical and chemical characterization results. For HTC at 260 °C, the proposed semi-continuous system showed approximately 3% higher carbon content in the obtained hydrochar and a 25-min reduction in required time to reach 260 °C. The promising conclusion of these results is that by introducing continuous systems in HTC, not only will the time of the process cycle decrease, it will also achieve higher degrees of carbonization.
•A comparative characterization of HTC and torrefaction is proposed.•The reaction temperature is the most governing parameter in the HTC process.•The inorganic compositions of biomass were ...significantly reduced via HTC.•The hydrochar produced at 260°C shows fuel qualities comparable to that of coal.
The work presented in this study demonstrates the potential of using hydrothermal carbonization (HTC) on miscanthus feedstock for the production of a carbon-rich solid fuel, referred to as hydrochar, whose physicochemical properties are comparable to that of coal. The effects of the processing conditions on the mass yield, energy yield and higher heating values (HHVs) were examined by varying the reaction temperature (190, 225, and 260°C), the reaction time (5, 15, and 30min) and the feedstock-to-water ratio (1:6 and 1:12). The results show that the reaction temperature is the most significant parameter governing the physicochemical properties of biomass. Increasing reaction temperature reduces the mass yield; however, it also significantly enhances the energy density of solid products. The hydrochar samples produced at 260°C show a maximum energy density of 26–30MJ/kg, with 66–74% of energy retained in the solid product. In comparison, the energy density, grindability, and hydrophobicity of the solid samples produced via torrefaction (a conventional thermal pre-treatment) were considerably lower than the hydrochar samples, even if the reaction time was kept much higher than HTC. Furthermore, the inorganic metallic composition of miscanthus feedstock almost remained unaffected after torrefaction; however, it was significantly reduced (30–70%) via HTC.
Depleting petroleum reserves together with the associated environmental concerns have intensified the exploration of alternatives to petroleum. Wet food processing wastes present promising ...bioresources for liquid fuel production via hydrothermal liquefaction (HTL) followed by additional upgrading. In this study, tomato plant waste (TPW) was utilized as a feedstock for the production of bio-crude oils via HTL at medium-temperature (220–280 °C) in water or a water–ethanol (17/3, v/v) medium in a 600 mL autoclave reactor. Effects of various operating parameters, such as catalysts (H2SO4 or KOH), reaction time (15–60 min) and reaction temperature (220–280 °C) on product yields were investigated. This study showed that a high yield (45.1 wt%) of bio-crude oil was achieved from HTL of TPW in water–ethanol medium at 250 °C in the presence of acid catalyst H2SO4. The oil, gas and solid residue (SR) products were analyzed for their chemical and structural properties.
This study provides fundamental insight and offers a promising catalytic hydrothermal method to harness cranberry pomace as a potential bioenergy and/or hydrochar source. The physical and chemical ...properties of Canadian cranberry pomace, supplied by Fruit d’Or Inc., were examined and the optimum operational conditions, in terms of biocrude yield, were obtained by the I-optimal matrix of Design Expert 11. Afterward, cranberry pomace hydrochar (CPH) and zeolite were separately introduced to the hydrothermal liquefaction (HTL) process to investigate the benefits and disadvantages associated with their catalytic activity. CPH was found to be a better host than zeolite to accommodate cellulosic sugars and showed great catalytic performance in producing hydrocarbons. However, high amounts of corrosive amino and aliphatic acids hinder the practical application of CPH as a catalyst. Alternatively, zeolite, as a commercial high surface area catalyst, had a higher activity for deoxygenation of compounds containing carbonyl, carboxyl, and hydroxyl groups than CPH and resulted in higher selectivity of phenols. Due to the low hydrothermal structural stability, coke formation, and narrow pore size distribution, further activations and modifications are needed to improve the catalytic behavior of zeolite. Our results suggest that a composite composed of CPH and zeolite can resolve the abovementioned limitations and help with the development and commercialization of advanced biofuels from cranberry pomace.
In this research fall time harvested corn residue (CR) was first mechanically pretreated to produce 5 mm chopped and <500 µm ground particles, which underwent an anaerobic digestion (AD) process to ...produce biomethane and biofertilizer. Another sample of CR was pretreated by an alkaline hydrothermal (HT) process using 1%, 2% and 3% NaOH to produce solid biocarbon and the resulting alkaline hydrothermal process water (AHTPW), a co-product of biocarbon, underwent fast digestion under AD conditions to produce biomethane and biofertilizer. A predetermined HT process of 240 °C for 30 min was considered and the effect of alkali content on the HT process for biocarbon and biomethane product a rate of 8.21 MJ kg−1 and 9.23 MJ kg−1 of raw CR, respectively. Among the three selected alkaline HT processes, the 1% NaOH HT process produced the highest hybrid bioenergy of 11.39 MJ kg−1 of raw CR with an overall energy recovery of 62.82% of raw CR. The AHTPW of 2% and 3% NaOH HT-treated CR did not produce considerable amount of biomethane and their biocarbons contained 3.44 MJ kg−1 and 3.27 MJ kg−1 of raw CR of bioenergy, respectively. The biomethane produced from 5 mm chopped CR, <500 µm ground CR and 1% alkaline AHTPW for 30 days retention time were of 275.38 L kg−1 volatile solid (VS), 309.59 L kg−1 VS and 278.70 L kg−1 VS, respectively, compared to non-treated CR of 144–187 L kg−1 VS. Nutrient enriched AD digestate is useable as liquid fertilizer. Biocarbon, biomethane and biofertilizer produced from the 1% alkaline HT process at 240 °C for 30 min can reduce the greenhouse gas (GHG) emissions of Ontario.
Corn stover (CS) contains high moisture in the fall and farmers keep it unharvested until next spring for its natural drying. CS contains 70% more carbon than other grain crop residues. Farmers ...traditionally use a portion of CS for livestock bedding and cattle feed but the rest is kept unharvested. Potential soil erosion, carbon sequestration, and nutrient removal concerns might be considered before CS harvesting. Hydrothermal carbonization (HTC) of wet biomass can produce energy dense solid bio-carbon. Hydrothermal process water (HTPW) can produce energy and recover nutrient in anaerobic digestion (AD). This study reported the results of various experiments performed on non-rooted fall harvested CS of an Ontario farm. Ontario CS was finally assessed for techno-economic and environmental aspects. This research showed 78% energy and a portion on nutrients as liquid bio-fertilizer of fall harvested CS are recoverable. Corn roots with 6–10 cm stalks, cobs and husks can be kept in the soil to recover soil organic matter (SOM) and protection of soil erosion. The process indicates the sustainable CS harvesting in the fall with possibility to reduce 75% of existing harvesting cost and reduction of greenhouse gas (GHG) emission.
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