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At least 1,063 records · Page 59

Sustainability assessment of alternative jet fuel for the U.S. Department of Defense

The United States Department of Defense (DoD) is considering replacing the 2.8 billion gallons of petroleum jet fuel consumed within the continental United States (CONUS) annually with alternative jet fuels to reduce vulnerability to price and supply fluctuations and improve sustainability. We evaluate the feasibility of replacing DoD CONUS jet fuel with alternative jet fuel from domestic feedstocks and assess the cost, greenhouse gas (GHG) emissions, energy balance, land, water, and fertilizer impacts of nine alternative jet fuel pathways. The feedstocks include terrestrial crops (soy, corn, wood, and grass), marine microalgae, and by-products (forestry residue, municipal solid waste, and waste oil) converted by extraction, fermentation, or thermo-chemical conversion, paired with upgrading steps. We found that domestic biomass feedstocks can meet the DoD CONUS jet fuel demand without significantly affecting food supply. Alternative pathways cost more than petroleum jet fuel ($0.78 l -1 and emitting 89 g CO 2 equivalent (CO 2e ) MJ -1 ), but many lowered GHG emissions. The forestry residue and waste oil pathways yielded the lowest costs ($\$0.92$ and $\$0.82$ l -1 , respectively), decreased emissions (23 and 35 g CO 2 e MJ -1 , respectively), and had negligible effects on land, water, and fertilizer resources. Finally, tradeoffs among sustainability metrics are further explored with a sensitivity analysis and by evaluating carbon-cost scenarios.

09 BIOMASS FUELS↗

Biomass supply chain equipment for renewable fuels production: A review

The production of renewable fuels is a critical component of global strategies to reduce greenhouse gas (GHG) emissions. Moreover, the collection of raw materials for its production can provide added benefits such as reduction of wildfire risk, additional income for farmers, and decreased disposal costs. Although there is substantial literature on design and modeling of supply chains, the authors were unable to find a single reference with the information needed for the selection and cost estimation of each type of equipment involved in the supply chain. Therefore, the goal of this research is to gather information necessary for the construction and utilization of models that might drive the identification of a feasible supply chain to produce renewable fuels at a commercial scale. The primary objectives are to 1) understand the supply chain of critical feedstocks for renewable fuels production; 2) identify the equipment commercially available for collection and adequation of feedstock; and 3) consolidate information regarding equipment cost, energy consumption, and efficiency, as well as feedstock storage and transportation systems. This paper provides a compilation for five feedstock types studied for sustainable aviation fuel production: 1) agricultural residues and grasses, 2) forest residues, 3) urban wood waste, 4) oilseeds, 5) fats, oils & greases. All the technologies involved from the field to the gate of the preprocessing or conversion unit were reviewed. The information on fats, oils & greases supply chains and equipment purposely designed for forest thinning and pruning was very limited.

: Feedstock, Collection and Adequation, Renewable ↗

Enhancing the flowability of woody biomass slurries in wet biorefineries

Feeding wet lignocellulosic biomass (e.g., softwood and hardwood) slurries into high-pressure, high-temperature reactors at an industrially relevant scale presents significant challenges, such as process equipment plugging. Here, in this study, we investigate the possibility of improving the flowability of biomass slurries in an industrial scale wet biorefinery by tuning the physical and chemical characteristics of the biomass particles. To understand the effects of the chemical characteristics of woody biomass on flowability, cellulose pulp particles are produced from pulp sheets via knife milling, pelletizing, and crumbling. These cellulose pulp particles are processed for acid hydrolysis dehydration (AHDH) at one –tonne-per day pilot scale. The levulinic acid yield (a product of cellulose AHDH) and the flowability of the biomass particles are compared using market pulp, 1 mm crumbled pine softwood, a blend of 2 mm hammer-milled pine softwood with 10 wt.% bark, and 2 mm hammer-milled hardwood material with 10 wt.% bark (to represent forest residues). The results indicate that the presence of hemicellulose and lignin influences the flowability of lignocellulosic feedstocks. Crumbled wood particles show poor flowability at the pilot scale, while the presence of fine materials (less than 0.7 mm) and bark improves the flowability of biomass slurries without affecting the organic acid yields (based on C6 carbohydrate content).

09 - BIOMASS FUELS↗

Membrane assisted continuous production of solvents with integrated solvent removal using liquid-liquid extraction

The aim was to demonstrate an industrially relevant pilot scale integrated process to produce butanol and other solvents from lignocellulosic sugars produced with AVAP® biomass fractionation technology from southern pine wood. The concentrated sugars were concurrently fermented using genetically engineered Clostridium acetobutylicum to n-butanol, acetone, isopropanol and ethanol in continuous membrane assisted cell recycle fermentation with steady-state solvent productivity exceeding 10 g/L/h. The solvents from the cell free permeate were recovered with extractant of butyl butyrate in a continuous liquid-liquid extraction column and aqueous product (raffinate) along with unused sugars, nutrients, and metabolic intermediates were recycled back to the fermentors. The total solvent yield approached 0.30 g/g sugars.

09 BIOMASS FUELS↗

Development of a universal method for high yield of furfural and hydrogen from raw lignocellulosic biomass

In order to develop a universal method for the co-production of furfural and hydrogen from raw lignocellulosic biomass, three types of substrates (maple wood, wheat straw, and tall fescue) were investigated, integrating chemical and electrochemical technologies. The results show both furfural and pure hydrogen were produced from all the biomass substrates, and the substrate type, composition, concentration, and size all affected furfural and hydrogen production. The highest furfural production of 154 mg g -1 substrate was achieved from wheat straw. The highest conversion rate of 67% for the waste furfural residue was realized, and 335 ml pure hydrogen per gram of furfural residue with a Faradaic efficiency of 99.3% was obtained with a new electrolytic cell. A reaction mechanism for hydrogen evolution from furfural residue and a rule for co-production of furfural and hydrogen from raw biomass were proposed. The facts show that a promising universal method for the co-production of furfural and hydrogen from lignocellulosic biomass has been developed.

08 HYDROGEN↗

Simulations of flaming combustion and flaming-to-smoldering transition in wildland fire spread at flame scale

Our objective in the present study is to provide basic insights into the coupling between external-gas and solid biomass vegetation processes that control the dynamics of flame spread in wildland fire problems. Here we focus on a modeling approach that resolves processes occurring at vegetation and flame scales, i.e., the formation of flammable vapors due to the thermal degradation of the solid biomass, the subsequent combustion in ambient air, the thermal feedback to the biomass through radiative and convective heat transfer, and the possible transition from flaming combustion (taking place outside of the solid biomass) to smoldering combustion (taking place inside the solid biomass). The capability uses a multiphase combustion framework and treats external-gas processes through a Large Eddy Simulation solver and solid biomass processes through a discrete particle model. The discrete particle model adopts a one-dimensional porous medium formulation, includes descriptions of drying, thermal pyrolysis, oxidative pyrolysis, and char oxidation, as well as a description of the external-gas-to-solid-biomass diffusion of oxygen mass; the discrete particle model thereby provides a treatment of in-depth oxidative processes and allows the simulation of smoldering combustion. The modeling capability is applied to the simulation of fire spread across a surrogate biomass vegetation bed corresponding to a discrete array of cylindrical-shaped, vertically-oriented, pine wood sticks, characterized by a monomodal size distribution, in horizontal flat terrain and under wind-aided conditions. The numerical results demonstrate that the model can simulate successful flaming-to-smoldering transition followed by complete biomass consumption.

01 COAL, LIGNITE, AND PEAT↗

ITreeForeCast: An integrated modeling software to simulate tree level growth and forest carbon storage

Healthy trees in forest act as a natural carbon sink, capturing carbon. As they grow, they store carbon in their trunks, leaves and roots. Not all trees store carbon at the same rate, or in the same quantities, as it depends on a variety of biophysical and climatic factors. Furthermore, although carbon estimation in trees can be complex, the precision of estimates is tightly linked to trees growth, both in diameter and height. However, the simulation of carbon uptake by forest and forest growth has each been modeled separately, and independently at differing levels of detail and spatial resolution. In this paper, we introduce ITreeForeCast, a simulation model combining the two types of modeling on a unified platform, enabling the investigation of impacts of management strategies on carbon sequestration and wood products. ITreeForeCast is a user-extendable framework that offers new opportunities to model, simulate, and visualize the dynamics of individual trees in a forest, simulate management strategies over time, and carbon uptake.

09 - BIOMASS FUELS↗

Bio-treatment of poplar via amino acid for interface control in biocomposites

Advanced biocomposites reinforced by abundant biomass-derived fillers can add a revenue stream to enhance the economic viability of biofuel production chains and the energy efficiency of the composite industry. However, the low stiffness of biopolymers limits their use in structural applications. Poplar fibers (mesh size: <180 μm, Populus spp.), an abundant waste from the wood industry, were used as bio-filler to fabricate high-performance biocomposites based on polylactic acid (PLA), in which the poplar fibers were modified by an amino acid (l-lysine). As a benefit of the amino acid treatment, the tensile Young's moduli of the lysine/poplar/PLA composites increased by up to 68% with the addition of a small amount of lysine, compared with neat PLA. At the same time, the tensile strength, failure strain, and Young's modulus of the poplar/PLA composites all increased after adding only 0.1 wt % of lysine. It has been observed that the lysine content has a significant effect on the decomposition temperature, complex viscosity, storage modulus, crystallization temperature, and crystallinity of composites. The fracture surfaces of the composites with an optimum lysine content had fewer voids and were more compact compared with composites without any lysine. The pores on the surfaces of poplar fibers became more available for the penetration of PLA molecules as a result of lysine addition. Finally, this study presents a facile method for reinforcing biocomposites with extremely low-cost and environmentally friendly biofillers.

59 BASIC BIOLOGICAL SCIENCES↗

In-plane crashworthiness of bio-inspired hierarchical honeycombs

Biological tissues like bone, wood, and sponge possess hierarchical cellular topologies, which are lightweight and feature an excellent energy absorption capability. Here we present a system of bio-inspired hierarchical honeycomb structures based on hexagonal, Kagome, and triangular tessellations. The hierarchical designs and a reference regular honeycomb configuration are subjected to simulated in-plane impact using the nonlinear finite element code LS-DYNA. The numerical simulation results show that the triangular hierarchical honeycomb provides the best performance compared to the other two hierarchical honeycombs, and features more than twice the energy absorbed by the regular honeycomb under similar loading conditions. We also propose a parametric study correlating the microstructure parameters (hierarchical length ratio r and the number of sub cells N) to the energy absorption capacity of these hierarchical honeycombs. The triangular hierarchical honeycomb with N = 2 and r = 1/8 shows the highest energy absorption capacity among all the investigated cases, and this configuration could be employed as a benchmark for the design of future safety protective systems.

36 MATERIALS SCIENCE↗

Towards smarter green infrastructure: Fusing bark ecology and stemflow hydrodynamics on tree stems

A wide array of bark surfaces sheath wooded plants in rural and urban areas alike. Much work has examined the function and role of bark in different contexts and different environs, including urban areas, finding that it is rich in life and can play a role in the transfer of water and matter to the ground surface. Accordingly, this paper presents a first step to weld and fuse bark ecology and stemflow hydrodynamics. It is an effort to develop a physically-based understanding of the transport of water and matter (e.g., solutes, particulates, microorganisms) along tree stems using relevant equations to allow a more informed consideration of bark in green infrastructure initiatives. In particular, the hydrodynamical equations are based on the conservation of water mass, conservation of momentum, and conservation of scalar mass. These equations, coupled with contemplation of corticular life, underpin and substantiate bark’s unifying role as a modulator and cultivator. By elucidating the ‘black box’ of the tree stem and utilizing the formulations set forth in this paper, urban foresters and planners can develop green infrastructure to help advance ecosystem services and sustainability development goals (SDG), especially SDG 11 and SDG 15.

60 APPLIED LIFE SCIENCES↗

The Strategic Environment Assessment bibliographic network: A quantitative literature review analysis

Academic literature has been continuously growing at such a pace that it can be difficult to follow the progression of scientific achievements; hence, the need to dispose of quantitative knowledge support systems to analyze the literature of a subject. In this article we utilize network analysis tools to build a literature review of scientific documents published in the multidisciplinary field of Strategic Environment Assessment (SEA). The proposed approach helps researchers to build unbiased and comprehensive literature reviews. We collect information on 7662 SEA publications and build the SEA Bibliographic Network (SEABN) employing the basic idea that two publications are interconnected if one cites the other. We apply network analysis at macroscopic (network architecture), mesoscopic (sub graph) and microscopic levels (node) in order to i) verify what network structure characterizes the SEA literature, ii) identify the authors, disciplines and journals that are contributing to the international discussion on SEA, and iii) scrutinize the most cited and important publications in the field. Results show that the SEA is a multidisciplinary subject; the SEABN belongs to the class of real small world networks with a dominance of publications in Environmental studies over a total of 12 scientific sectors. Christopher Wood, Olivia Bina, Matthew Cashmore, and Andrew Jordan are found to be the leading authors while Environmental Impact Assessment Review is by far the scientific journal with the highest number of publications in SEA studies. - Highlights: • We utilize network analysis to analyze scientific documents in the SEA field. • We build the SEA Bibliographic Network (SEABN) of 7662 publications. • We apply network analysis at macroscopic, mesoscopic and microscopic network levels. • We identify SEABN architecture, relevant publications, authors, subjects and journals.

54 ENVIRONMENTAL SCIENCES↗

Assessing land take by urban development and its impact on carbon storage: Findings from two case studies in Italy

Highlights: • We tested a new methodology for monitoring land take and its effects on C storage. • The ecological impact of urban growth derives from the previous land use. • C loss increases with the naturalness of the territory. • Different urban assets may imply different forms of land take containment. Land take due to urbanization triggers a series of negative environmental impacts with direct effects on quality of life for people living in cities. Changes in ecosystem services are associated with land take, among which is the immediate C loss due to land use conversion. Land use change monitoring represents the first step in quantifying land take and its drivers and impacts. To this end, we propose an innovative methodology for monitoring land take and its effects on ecosystem services (in particular, C loss) under multi-scale contexts. The devised approach was tested in two areas with similar sizes, but different land take levels during the time-span 1990–2008 in Central Italy (the Province of Rome and the Molise Region). The estimates of total coverage of built up areas were calculated using point sampling. The area of the urban patches including each sampling point classified as built up areas in the year 1990 and/or in the year 2008 is used to estimate total abundance and average area of built up areas. Biophysical and economic values for carbon loss associated with land take were calculated using InVEST. Although land take was 7–8 times higher in the Province of Rome (from 15.1% in 1990 to 20.4% in 2008) than in Molise region, our findings show that its relative impact on C storage is higher in the latter, where the urban growth consistently affects not only croplands but also semi-natural land uses such as grasslands and other wooded lands. The total C loss due to land take has been estimated in 1.6 million Mg C, corresponding to almost 355 million €. Finally, the paper discusses the main characteristics of urban growth and their ecological impact leading to risks and challenges for future urban planning and land use policies.

54 ENVIRONMENTAL SCIENCES↗

Life cycle assessment and cost analysis of hybrid fiber-reinforced engine beauty cover in comparison with glass fiber-reinforced counterpart

Life cycle assessment is a useful tool that helps to quantify the ecological impact of a product. It also enables us to compare two products. Regardless of its weaknesses, this tool is by far one of the best methods introduced and is one of the most complicated techniques available for environmental assessment. While the benefit of using bio-based materials instead of synthetic materials is well known, to date very few studies are available comparing the two products. The aim of this paper is to compare a currently available car engine beauty cover with a hybrid bio-based cover. This study's results show that the new hybrid materials not only perform better in terms of emissions during car operation (because of the fuel savings resulting from lightweighting), but that their production and end of life is also environmentally benign. A cost analysis of the two types of engine covers shows that the new hybrid materials are a good substitute for current materials because their manufacture costs half that of current materials. - Highlights: •Hybrid composite surpasses glass fiber composite although it has 10% carbon fiber. •The cost of producing the part out of hybrid material is lower than glass fiber. •The natural fibers contained composite had a better performance on eutrophication. •Hybrid composite outperforms in all the impact categories but the water and wood.

54 ENVIRONMENTAL SCIENCES↗

Evaluation of the environmental impact assessment system and implementation in Myanmar: Its significance in oil and gas industry

Myanmar's political and economic transformation and drastic expansion of foreign direct investment in natural resource sector necessitate systematic safeguards to mitigate impacts from its development activities. Myanmar promulgated the first national EIA law and procedure only recently, in 2016, and the country's institutional and financial capacity is extremely limited to implement effective EIA. This article evaluates Myanmar's EIA system against a set of evaluative criteria developed by Wood (1995) and modified by Annandle (2001). The evaluation was based on the review of the literature, investigation of EIA legislative and administrative framework, and several other sources of data and information. Opinions of professionals from international and government agencies, and researchers are also solicited. The paper then evaluates the rate of EIA disclosure in O&G sector and whether EIA in Myanmar is significance in mitigating the impact of O&G operations on the environment. The review of EIA system indicates that Myanmar generally has sound legal and administrative framework for EIA, however, its practical implementation reveals several major challenges and weaknesses. The presence of more than one standard EIA procedure and lack of inter-departmental coordination and consultation are also major concerns. Overall, the quality of EIA reports and the level of disclosure in O&G sector is higher than that of other sectors in Myanmar. Through the analysis, the paper summarizes the fundamental challenges faced by companies and government, opportunities and good practices in implementing EIA systems and propose recommendations to strengthen EIA performance. The findings of this study expect to contribute to strengthening EIA system and performance in Myanmar and other developing countries, especially in Southeast Asia.

02 PETROLEUM↗

Effect of Carbon and Binder on High Sulfur Loading Electrode for Li-S Battery Technology

For the Lithium-Sulfur (Li-S) battery to be competitive in commercialization, it is requested that the sulfur electrode must have deliverable areal capacity > 8 mAh cm -2 , which corresponds to a sulfur loading > 6 mg cm -2 . At this relatively high sulfur loading, we evaluated the impact of binder and carbon type on the mechanical integrity and the electrochemical properties of sulfur electrodes. We identified hydroxypropyl cellulose (HPC) as a new binder for the sulfur electrode because it offers better adhesion between the electrode and the aluminum current collector than the commonly used polyvinylidene fluoride (PVDF) binder. In combination with the binder study, multiple types of carbon with high specific surface area were evaluated as sulfur hosts for high loading sulfur electrodes. A commercial microporous carbon derived from wood with high pore volume showed the best performance. An electrode with sulfur loading up to 10 mg cm -2 was achieved with the optimized recipe. Based on systematic electrochemical studies, the soluble polysulfide to insoluble Li 2 S 2 /Li 2 S conversion was identified to be the major barrier for high loading sulfur electrodes to achieve high sulfur utilization.

25 ENERGY STORAGE↗

Biomass char gasification kinetic rates compared to data, including ash effects

This investigation provides both experimental and theoretical analyses of biomass char gasification kinetics over 1150–1350 °C in the environment of CO 2 , H 2 O and combinations of these reactants. The experimental data include continuous measurements of particle mass, external and internal temperatures, shape, and size with periodic but not continuous measurements of char porosity, pore size distribution, and pore surface area. The model describes heterogeneous char gasification for poplar wood, corn stover and switchgrass in different shapes and industrially relevant sizes (12.5 mm and smaller). Nonlinear least-squares regression produces optimized power-law model parameters for global kinetics that describe biomass char gasification with respect to both CO 2 and H 2 O separately and in combination. A single set of kinetic parameters describes reaction rates for all three fuels. Model simulations agree with measured data at all stages of char conversion even though the observed mass loss rates change significantly with conversion. In conclusion, the change in rate with conversion depends strongly on ash content, and this investigation provides a simple and theoretically based reaction rate expression that includes the effect of inert ash occupying an increasing portion of the reactive surface with increased conversion.

09 BIOMASS FUELS↗